中英文文献翻译—关于汽车喷油泵端面凸轮轨道冷锻的研究
毕业设计翻译
山东理工大学毕业设计（论文）外文翻译资料英文题目：Experimental verification and finite element modeling of radial truck tireunder static loading翻译题目：车辆轮胎径向固有频率和阻尼系数的研究学院：交通与车辆工程学院专业：车辆工程学生姓名：王臣指导教师：刘瑞军车辆轮胎径向固有频率和阻尼系数的研究摘要--车辆轮胎径向固有频率和阻尼比的测量方法已经有所研究。
从小客车轮胎到货车巴士轮胎的径向固有频率和阻尼比都已经被报道。
轮胎的径向模态参数承受不同水平的充气压力，已通过使用频率响应函数的方法来确定。
为了获得理论上的固有频率和振型，轮胎的平面振动已被建模为貌似一个圆形光束的模型。
使用Tielking方法是基于Hamilton原理，理论结果证实旋转速度，切向和径向刚度，径向速度和拉力是由于轮胎的充气压力造成的。
结果表明，实验条件下可以认为是参数改变了固有频率和阻尼比。
关键词-阻尼比、频率响应函数法、充气压力、模态振型、径向固有频率、子午线轮胎1. 引言在当今世界，通过减少汽车的震动，提高驾驶的质量具有重要意义。
通常情况下，很多汽车的振动来源于刚发动的时候，振动速率的影响逐渐增加。
特别是，轮胎不仅作为初始旋转接触路面，从路面影响传送到汽车的主体进入汽车的内部，而且，在于轮胎已经对增强乘坐的质量有很大的影响。
回顾在轮胎振动上已建立的研究，Tielking研究飞机充气轮胎的振动特性，假定轮胎的运动是圆形壳的运动。
有Tielking理论的基本原则，Bohm通过研究轮胎运动和静止的特征同时假设轮胎是弹性环，提出了轮胎的运动方程。
Bohm用实验的方法来验证了他的方程。
Barons也研究了振动对旋转轮胎的影响。
Potts等人建模的轮胎为薄环，并考虑到质量和几何形状研究了轮胎的固有频率。
Soedel 和Prasad等人用分析方法研究了轮胎在路表面载荷下的振动特性，例如，解释在自由状态下的振动特性。
毕业设计论文外文文献翻译机械设计制造及其自动化轴承的摩擦与润滑中英文对照
Friction , Lubrication of BearingIn many of the problem thus far , the student has been asked to disregard or neglect friction . A ctually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement.Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary.The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. A lso , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt.There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding,and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. T o produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement .Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. A s shown in figure ,starting friction is always greater than sliding friction .Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction.The friction caused by the wedging action of surface irregularities can be overcome partly by the precision machining of the surfaces. However, even these smooth surfaces may require the use of a substance between them to reduce the friction still more. This substance is usually a lubricant which provides a fine, thin oil film. The film keeps the surfaces apart and prevents the cohesive forces of the surfaces from coming in close contact and producing heat .Another way to reduce friction is to use different materials for the bearing surfaces and rotating parts. This explains why bronze bearings, soft alloy s, and copper and tin iolite bearings are used with both soft andhardened steel shaft. The iolite bearing is porous. Thus, when the bearing is dipped in oil, capillary action carries the oil through the spaces of the bearing. This type of bearing carries its own lubricant to the points where the pressures are the greatest.Moving parts are lubricated to reduce friction, wear, and heat. The most commonly used lubricants are oils, greases, and graphite compounds. Each lubricant serves a different purpose. The conditions under which two moving surfaces are to work determine the type of lubricant to be used and the system selected for distributing the lubricant.On slow moving parts with a minimum of pressure, an oil groove is usually sufficient to distribute the required quantity of lubricant to the surfaces moving on each other .A second common method of lubrication is the splash system in which parts moving in a reservoir of lubricant pick up sufficient oil which is then distributed to all moving parts during each cycle. This system is used in the crankcase of lawn-mower engines to lubricate the crankshaft, connecting rod ,and parts of the piston.A lubrication system commonly used in industrial plants is the pressure system. In this system, a pump on a machine carries the lubricant to all of the bearing surfaces at a constant rate and quantity.There are numerous other sy stems of lubrication and a considerable number of lubricants available for any given set of operating conditions. Modern industry pays greater attention to the use of the proper lubricants than at previous time because of the increased speeds, pressures, and operating demands placed on equipment and devices.Although one of the main purposes of lubrication is reduce friction, any substance-liquid , solid , or gaseous-capable of controlling friction and wear between sliding surfaces can be classed as a lubricant.V arieties of lubricationUnlubricated sliding. Metals that have been carefully treated to remove all foreign materials seize and weld to one another when slid together. In the absence of such a high degree of cleanliness, adsorbed gases, water vapor ,oxides, and contaminants reduce frictio9n and the tendency to seize but usually result in severe wear。
毕业设计外文翻译英文加中文
A Comparison of Soft Start Mechanisms for Mining BeltConveyors1800 Washington Road Pittsburgh, PA 15241 Belt Conveyors are an important method for transportation of bulk materials in the mining industry. The control of the application of the starting torque from the belt drive system to the belt fabric affects the performance, life cost, and reliability of the conveyor. This paper examines applications of each starting method within the coal mining industry.INTRODUCTIONThe force required to move a belt conveyor must be transmitted by the drive pulley via friction between the drive pulley and the belt fabric. In order to transmit power there must be a difference in the belt tension as it approaches and leaves the drive pulley. These conditions are true for steady state running, starting, and stopping. Traditionally, belt designs are based on static calculations of running forces. Since starting and stopping are not examined in detail, safety factors are applied to static loadings (Harrison, 1987). This paper will primarily address the starting or acceleration duty of the conveyor. The belt designer must control starting acceleration to prevent excessive tension in the belt fabric and forces in the belt drive system (Suttees, 1986). High acceleration forces can adversely affect the belt fabric, belt splices, drive pulleys, idler pulleys, shafts, bearings, speed reducers, and couplings. Uncontrolled acceleration forces can cause belt conveyor system performance problems with vertical curves, excessive belt take-up movement, loss of drive pulley friction, spillage of materials, and festooning of the belt fabric. The belt designer is confronted with two problems, The belt drive system must produce a minimum torque powerful enough to start the conveyor, and controlled such that the acceleration forces are within safe limits. Smooth starting of the conveyor can be accomplished by the use of drive torque control equipment, either mechanical or electrical, or a combination of the two (CEM, 1979).SOFT START MECHANISM EVALUATION CRITERIONWhat is the best belt conveyor drive system? The answer depends on many variables. The best system is one that provides acceptable control for starting, running, and stopping at a reasonable cost and with high reliability (Lewdly and Sugarcane, 1978). Belt Drive System For the purposes of this paper we will assume that belt conveyors are almost always driven byelectrical prime movers (Goodyear Tire and Rubber, 1982). The belt "drive system" shall consist of multiple components including the electrical prime mover, the electrical motor starter with control system, the motor coupling, the speed reducer, the low speed coupling, the belt drive pulley, and the pulley brake or hold back (Cur, 1986). It is important that the belt designer examine the applicability of each system component to the particular application. For the purpose of this paper, we will assume that all drive system components are located in the fresh air, non-permissible, areas of the mine, or in non-hazardous, National Electrical Code, Article 500 explosion-proof, areas of the surface of the mine.Belt Drive Component Attributes SizeCertain drive components are available and practical in different size ranges. For this discussion, we will assume that belt drive systems range from fractional horsepower to multiples of thousands of horsepower. Small drive systems are often below 50 horsepower. Medium systems range from 50 to 1000 horsepower. Large systems can be considered above 1000 horsepower. Division of sizes into these groups is entirely arbitrary. Care must be taken to resist the temptation to over motor or under motor a belt flight to enhance standardization. An over motored drive results in poor efficiency and the potential for high torques, while an under motored drive could result in destructive overspending on regeneration, or overheating with shortened motor life (Lords, et al., 1978).Torque ControlBelt designers try to limit the starting torque to no more than 150% of the running torque (CEMA, 1979; Goodyear, 1982). The limit on the applied starting torque is often the limit of rating of the belt carcass, belt splice, pulley lagging, or shaft deflections. On larger belts and belts with optimized sized components, torque limits of 110% through 125% are common (Elberton, 1986). In addition to a torque limit, the belt starter may be required to limit torque increments that would stretch belting and cause traveling waves. An ideal starting control system would apply a pretension torque to the belt at rest up to the point of breakaway, or movement of the entire belt, then a torque equal to the movement requirements of the belt with load plus a constant torque to accelerate the inertia of the system components from rest to final running speed. This would minimize system transient forces and belt stretch (Shultz, 1992). Different drive systems exhibit varying ability to control the application of torques to the belt at rest and at different speeds. Also, the conveyor itself exhibits two extremes of loading. An empty belt normally presents the smallest required torque for breakaway and acceleration, while a fully loaded belt presents the highest required torque. A mining drive system must be capable of scaling the applied torque from a 2/1 ratio for a horizontal simple belt arrangement, to a 10/1 ranges for an inclined or complex belt profile.Thermal RatingDuring starting and running, each drive system may dissipate waste heat. The waste heat may be liberated in the electrical motor, the electrical controls,, the couplings, the speed reducer, or the belt braking system. The thermal load of each start Is dependent on the amount of belt load and the duration of the start. The designer must fulfill the application requirements for repeated starts after running the conveyor at full load. Typical mining belt starting duties vary from 3 to 10 starts per hour equally spaced, or 2 to 4 starts in succession. Repeated starting may require the dreading or over sizing of system components. There is a direct relationship between thermal rating for repeated starts and costs. Variable Speed. Some belt drive systems are suitable for controlling the starting torque and speed, but only run at constant speed. Some belt applications would require a drive system capable of running for extended periods at less than full speed. This is useful when the drive load must be shared with other drives, the belt is used as a process feeder for rate control of the conveyed material, the belt speed is optimized for the haulage rate, the belt is used at slower speeds to transport men or materials, or the belt is run a slow inspection or inching speed for maintenance purposes (Hager, 1991). The variable speed belt drive will require a control system based on some algorithm to regulate operating speed. Regeneration or Overhauling Load. Some belt profiles present the potential for overhauling loads where the belt system supplies energy to the drive system. Not all drive systems have the ability to accept regenerated energy from the load. Some drives can accept energy from the load and return it to the power line for use by other loads. Other drives accept energy from the load and dissipate it into designated dynamic or mechanical braking elements. Some belt profiles switch from motoring to regeneration during operation. Can the drive system accept regenerated energy of a certain magnitude for the application? Does the drive system have to control or modulate the amount of retarding force during overhauling? Does the overhauling occur when running and starting? Maintenance and Supporting Systems. Each drive system will require periodic preventative maintenance. Replaceable items would include motor brushes, bearings, brake pads, dissipation resistors, oils, and cooling water. If the drive system is conservatively engineered and operated, the lower stress on consumables will result in lower maintenance costs. Some drives require supporting systems such as circulating oil for lubrication, cooling air or water, environmental dust filtering, or computer instrumentation. The maintenance of the supporting systems can affect the reliability of the drive system.CostThe drive designer will examine the cost of each drive system. The total cost is the sum of the first capital cost to acquire the drive, the cost to install and commission the drive, thecost to operate the drive, and the cost to maintain the drive. The cost for power to operate the drive may vary widely with different locations. The designer strives to meet all system performance requirements at lowest total cost. Often more than one drive system may satisfy all system performance criterions at competitive costs.ComplexityThe preferred drive arrangement is the simplest, such as a single motor driving through a single head pulley.However,mechanical, economic,and functional requirements often necessitate the use of complex drives.The belt designer must balance the need for sophistication against the problems that accompany complex systems. Complex systems require additional design engineering for successful deployment. An often-overlooked cost in a complex system is the cost of training onsite personnel, or the cost of downtime as a result of insufficient training.SOFT START DRIVE CONTROL LOGICEach drive system will require a control system to regulate the starting mechanism. The most common type of control used on smaller to medium sized drives with simple profiles is termed "Open Loop Acceleration Control". In open loop, the control system is previously configured to sequence the starting mechanism in a prescribed manner, usually based on time. In open loop control, drive-operating parameters such as current, torque, or speed do not influence sequence operation. This method presumes that the control designer has adequately modeled drive system performance on the conveyor. For larger or more complex belts, "Closed Loop" or "Feedback" control may he utilized. In closed loop control, during starting, the control system monitors via sensors drive operating parameters such as current level of the motor, speed of the belt, or force on the belt, and modifies the starting sequence to control, limit, or optimize one or wore parameters. Closed loop control systems modify the starting applied force between an empty and fully loaded conveyor. The constants in the mathematical model related to the measured variable versus the system drive response are termed the tuning constants. These constants must be properly adjusted for successful application to each conveyor. The most common schemes for closed loop control of conveyor starts are tachometer feedback for speed control and load cell force or drive force feedback for torque control. On some complex systems, It is desirable to have the closed loop control system adjust itself for various encountered conveyor conditions. This is termed "Adaptive Control". These extremes can involve vast variations in loadings, temperature of the belting, location of the loading on the profile, or multiple drive options on the conveyor. There are three commonadaptive methods. The first involves decisions made before the start, or 'Restart Conditioning'. If the control system could know that the belt is empty, it would reduce initial force and lengthen the application of acceleration force to full speed. If the belt is loaded, the control system would apply pretension forces under stall for less time and supply sufficient torque to adequately accelerate the belt in a timely manner. Since the belt only became loaded during previous running by loading the drive, the average drive current can be sampled when running and retained in a first-in-first-out buffer memory that reflects the belt conveyance time. Then at shutdown the FIFO average may be use4 to precondition some open loop and closed loop set points for the next start. The second method involves decisions that are based on drive observations that occur during initial starting or "Motion Proving'. This usually involves a comparison In time of the drive current or force versus the belt speed. if the drive current or force required early in the sequence is low and motion is initiated, the belt must be unloaded. If the drive current or force required is high and motion is slow in starting, the conveyor must be loaded. This decision can be divided in zones and used to modify the middle and finish of the start sequence control. The third method involves a comparison of the belt speed versus time for this start against historical limits of belt acceleration, or 'Acceleration Envelope Monitoring'. At start, the belt speed is measured versus time. This is compared with two limiting belt speed curves that are retained in control system memory. The first curve profiles the empty belt when accelerated, and the second one the fully loaded belt. Thus, if the current speed versus time is lower than the loaded profile, it may indicate that the belt is overloaded, impeded, or drive malfunction. If the current speed versus time is higher than the empty profile, it may indicate a broken belt, coupling, or drive malfunction. In either case, the current start is aborted and an alarm issued.CONCLUSIONThe best belt starting system is one that provides acceptable performance under all belt load Conditions at a reasonable cost with high reliability. No one starting system meets all needs. The belt designer must define the starting system attributes that are required for each belt. In general, the AC induction motor with full voltage starting is confined to small belts with simple profiles. The AC induction motor with reduced voltage SCR starting is the base case mining starter for underground belts from small to medium sizes. With recent improvements, the AC motor with fixed fill fluid couplings is the base case for medium to large conveyors with simple profiles. The Wound Rotor Induction Motor drive is the traditional choice for medium to large belts with repeated starting duty or complex profilesthat require precise torque control. The DC motor drive, Variable Fill Hydrokinetic drive, and the Variable Mechanical Transmission drive compete for application on belts with extreme profiles or variable speed at running requirements. The choice is dependent on location environment, competitive price, operating energy losses, speed response, and user familiarity. AC Variable Frequency drive and Brush less DC applications are limited to small to medium sized belts that require precise speed control due to higher present costs and complexity. However, with continuing competitive and technical improvements, the use of synthesized waveform electronic drives will expand.REFERENCES[1]Michael L. Nave, P.E.1989.CONSOL Inc.煤矿业带式输送机几种软起动方式的比较1800 年华盛顿路匹兹堡, PA 15241带式运送机是采矿工业运输大批原料的重要方法。
有关冷却器外文翻译
本科生毕业设计外文翻译题目：机油冷却器内部压力分布研究学生姓名：赵欣学号：1264134136专业：过程装备与控制工程班级：装备12-1班指导教师：孟智慧Study on Pressure Distribution in Oil Cooler Abstract:The CFD method was applied and strip-fins were simplified as porous media as well．A new way to determine friction coefficient in porous media was presented，and a mathematical model concerning input pressure，number of heat exchanger layers and input velocity was derived，which can be utilized to predict the pressure in oil cooler．Keywords: Oil cooler; Porous media; PressurePlate fin oil cooler (oil cooler) is a typical compact heat exchanger, has high heat transfer efficiency, small volume, light weight, the advantages of shape design and installation position of the free, widely used in automobile,engineering machinery and other oil cooling of the engine. The needle to plate fin heat exchanger the heat transfer performance and resistance characteristics of a long time, scholars at home and abroad in a wide range of research, W M Kays and a l London of experiments based on the proposed heat exchanger core flow pressure drop calculation formula of the heat transfer and flow resistance of 90 kinds of fin design according to the number of 1; PAJ M manglik and Arthur e bergles put forward the expression of heat resistance factor J and factor f rectangular serrated fin, further study of the Reynolds number and fin size effects on the resistance characteristics of 2; e carluccio, G starace and other application number Numerical simulation technique is used to simplify the fin to the porous medium, and the thermal fluid dynamic characteristics of the oil side and the air side of the vehicle oil cooler are analyzed and studied.Lihua us, Jiangping Chen et al through physical experiments of 36 species of different sizes of serrated fin, using regression analysis method to obtain the relation between the oil side high pressure direction (HPD) heat transfer and pressure drop characteristics [4]; Zhang Yi using CFD /nht method conducts the research to the oil cooler oil flow and heat transfer problems, including import and export oil position on the oil cooler oil side of the pressure effect [5]; Guo Lihua, with the help of software of AN-SYS /fluent. Analysis of oil cooler, a core layer flow field and temperature field distribution [6].Oil cooler internal pressure distribution of oil in the core of each layer of the cooling flow state and distribution of decision, thus affecting the oil cooler of the overall heat transfer performance. In addition, the partial pressure of too high to cause the working life of the oil cooler reduced. Therefore, oil cooler internal oil side of the pressure distribution were studied, and to guide the oil cooler for thermal properties and local structure strength design and oil cooling device test parameters adjustment and virtual test rig a construction has important significance.At present, the heat exchanger fluid flow in the core of some scholars mostly along the width direction of the core dynamic unfolding. As for plate fin oil cooler, oil usually arranged at both ends of the oil cooler, oil inlet pipe first by diffusion flow to each layer of the heat exchanger, along the width to fully open after the contraction flow in the pipe. In addition, oil cooler is a closed entity with complex structure, including multilayer cooling core and a large number offins, and the flow law of oil complex. If the physical test method, high investment cost, long cycle, and it is difficult to explore the internal pressure distribution. In order to effectively characterize the flow state of oil in the oil cooler, with computational fluid dynamics (CFD) technology, the author will fin area is simplified as porous media model, and proposes a method for determining the resistance coefficient of porous medium model. Through the analysis of oil flow distribution are not uniform in every layer, core into, exit and internal pressure, the establishment of the internal pressure of the oil cooler on the inlet pressure, mathematical model of core layers, inlet velocity and other factors. In the inlet pressure and the velocity is known, oil cooler internal pressure on the size of the forecast.1.Serrated fin structureThe oil cooling device internal fin area simplified as porous media model, the use of computational fluid dynamics (CFD) technology, on the oil cooler internal oil flow state simulation analysis, can effectively learn the oil cooler internal pressure condition. Simulation results show that: in oil pressure distribution showed a "V" type, into the circuit at the end of the end under themaximum pressure value; core cooling in the pressure drop and oil inlet velocity, core layers I showed a quadratic variation; back to the oil pressure distribution can be determined by the outlet pressure of the cooling core. According to the simulation results of push derived oil cooler internal pressure formula can be used to predict in the inlet pressure and velocity is known and test conditions that determine the conditions, the oil cooling device internal into the circuit, each layer of core and oil pressure size, to change the thermal performance and reliability design basis for the improvement of oil coolers for.2.The pressure distribution inside the oil coreAccording to the application process of the collaborative manufacturing of collaborative manufacturing platform design scheme of manufacturing grid, resource service layer from the traditional grid architecture extracted as the resource node collaborative environment of service interface, and the design ofthe terminal resource collaborative environment, so as to achieve the resources to support hot deployment, do not need to restart is the implementation of the service, you can add new resources, and providing services. And the application prototype of the whole collaborative platform is built, and the modeling, the modulation degree, the management of manufacturing process and the resource management of the manufacturing grid are realized. The next step work is of platform and make further improvement and verification, will eventually platforms deployed in the region oriented application service system support to area of SMT product manufacturing collaboration, improve the competitive ability of the enterprise in the manufacturing, to achieve rapid response to the market.机油冷却器内部压力分布研究摘要: 运用计算流体力学 ( CFD) 技术，将机油冷却器翅片区域简化为多孔介质模型，研究在机油流动分配不均匀的条件下机油冷却器内部压力分布情况，提出一种确定多孔介质模型中阻力系数的方法以及表征油冷器内部压力关于进口压力、芯子层数、进口流速等因素的数学模型，实现了油冷器内部压力大小的预测。
机械加工毕业论文中英文资料外文翻译文献
毕业论文中英文资料外文翻译文献附录附录1：英文原文Selection of optimum tool geometry and cutting conditionsusing a surface roughness prediction model for end milling Abstract Influence of tool geometry on the quality of surface produced is well known and hence any attempt to assess the performance of end milling should include the tool geometry. In the present work, experimental studies have been conducted to see the effect of tool geometry (radial rake angle and nose radius) and cutting conditions (cutting speed and feed rate) on the machining performance during end milling of medium carbon steel. The first and second order mathematical models, in terms of machining parameters, were developed for surface roughness prediction using response surface methodology (RSM) on the basis of experimental results. The model selected for optimization has been validated with the Chi square test. The significance of these parameters on surface roughness has been established with analysis of variance. An attempt has also been made to optimize the surface roughness prediction model using genetic algorithms (GA). The GA program gives minimum values of surface roughness and their respective optimal conditions.1 IntroductionEnd milling is one of the most commonly used metal removal operations in industry because of its ability to remove material faster giving reasonably good surface quality. It is used in a variety of manufacturing industries including aerospace and automotive sectors, where quality is an important factor in the production of slots, pockets, precision moulds and dies. Greater attention is given to dimensional accuracy and surface roughness of products by the industry these days. Moreover, surface finish influences mechanical properties such as fatigue behaviour, wear, corrosion, lubrication and electrical conductivity. Thus, measuring and characterizing surface finish can be considered for predicting machining performance.Surface finish resulting from turning operations has traditionally received considerable research attention, where as that of machining processes using multipoint cutters, requires attention by researchers. As these processes involve large number of parameters, it would bedifficult to correlate surface finish with other parameters just by conducting experiments. Modelling helps to understand this kind of process better. Though some amount of work has been carried out to develop surface finish prediction models in the past, the effect of tool geometry has received little attention. However, the radial rake angle has a major affect on the power consumption apart from tangential and radial forces. It also influences chip curling and modifies chip flow direction. In addition to this, researchers [1] have also observed that the nose radius plays a significant role in affecting the surface finish. Therefore the development of a good model should involve the radial rake angle and nose radius along with other relevant factors.Establishment of efficient machining parameters has been a problem that has confronted manufacturing industries for nearly a century, and is still the subject of many studies. Obtaining optimum machining parameters is of great concern in manufacturing industries, where the economy of machining operation plays a key role in the competitive market. In material removal processes, an improper selection of cutting conditions cause surfaces with high roughness and dimensional errors, and it is even possible that dynamic phenomena due to auto excited vibrations may set in [2]. In view of the significant role that the milling operation plays in today’s manufacturing world, there is a need to optimize the machining parameters for this operation. So, an effort has been made in this paper to see the influence of tool geometry(radial rake angle and nose radius) and cutting conditions(cutting speed and feed rate) on the surface finish produced during end milling of medium carbon steel. The experimental results of this work will be used to relate cutting speed, feed rate, radial rake angle and nose radius with the machining response i.e. surface roughness by modelling. The mathematical models thus developed are further utilized to find the optimum process parameters using genetic algorithms.2 ReviewProcess modelling and optimization are two important issues in manufacturing. The manufacturing processes are characterized by a multiplicity of dynamically interacting process variables. Surface finish has been an important factor of machining in predicting performance of any machining operation. In order to develop and optimize a surface roughness model, it is essential to understand the current status of work in this area.Davis et al. [3] have investigated the cutting performance of five end mills having various helix angles. Cutting tests were performed on aluminium alloy L 65 for three milling processes (face, slot and side), in which cutting force, surface roughness and concavity of a machined plane surface were measured. The central composite design was used to decide on the number of experiments to be conducted. The cutting performance of the end mills was assessed usingvariance analysis. The affects of spindle speed, depth of cut and feed rate on the cutting force and surface roughness were studied. The investigation showed that end mills with left hand helix angles are generally less cost effective than those with right hand helix angles. There is no significant difference between up milling and down milling with regard tothe cutting force, although the difference between them regarding the surface roughness was large. Bayoumi et al.[4] have studied the affect of the tool rotation angle, feed rate and cutting speed on the mechanistic process parameters (pressure, friction parameter) for end milling operation with three commercially available workpiece materials, 11 L 17 free machining steel, 62- 35-3 free machining brass and 2024 aluminium using a single fluted HSS milling cutter. It has been found that pressure and friction act on the chip – tool interface decrease with the increase of feed rate and with the decrease of the flow angle, while the cutting speed has a negligible effect on some of the material dependent parameters. Process parameters are summarized into empirical equations as functions of feed rate and tool rotation angle for each work material. However, researchers have not taken into account the effects of cutting conditions and tool geometry simultaneously; besides these studies have not considered the optimization of the cutting process.As end milling is a process which involves a large number f parameters, combined influence of the significant parameters an only be obtained by modelling. Mansour and Abdallaet al. [5] have developed a surface roughness model for the end milling of EN32M (a semi-free cutting carbon case hardening steel with improved merchantability). The mathematical model has been developed in terms of cutting speed, feed rate and axial depth of cut. The affect of these parameters on the surface roughness has been carried out using response surface methodology (RSM). A first order equation covering the speed range of 30–35 m/min and a second order equation covering the speed range of 24–38 m/min were developed under dry machining conditions. Alauddin et al. [6] developed a surface roughness model using RSM for the end milling of 190 BHN steel. First and second order models were constructed along with contour graphs for the selection of the proper combination of cutting speed and feed to increase the metal removal rate without sacrificing surface quality. Hasmi et al. [7] also used the RSM model for assessing the influence of the workpiece material on the surface roughness of the machined surfaces. The model was developed for milling operation by conducting experiments on steel specimens. The expression shows, the relationship between the surface roughness and the various parameters; namely, the cutting speed, feed and depth of cut. The above models have not considered the affect of tool geometry on surface roughness.Since the turn of the century quite a large number of attempts have been made to find optimum values of machining parameters. Uses of many methods have been reported in the literature to solve optimization problems for machining parameters. Jain and Jain [8] have usedneural networks for modeling and optimizing the machining conditions. The results have been validated by comparing the optimized machining conditions obtained using genetic algorithms. Suresh et al. [9] have developed a surface roughness prediction model for turning mild steel using a response surface methodology to produce the factor affects of the individual process parameters. They have also optimized the turning process using the surface roughness prediction model as the objective function. Considering the above, an attempt has been made in this work to develop a surface roughness model with tool geometry and cutting conditions on the basis of experimental results and then optimize it for the selection of these parameters within the given constraints in the end milling operation.3 MethodologyIn this work, mathematical models have been developed using experimental results with the help of response surface methodolog y. The purpose of developing mathematical models relating the machining responses and their factors is to facilitate the optimization of the machining process. This mathematical model has been used as an objective function and the optimization was carried out with the help of genetic algorithms.3.1 Mathematical formulationResponse surface methodology(RSM) is a combination of mathematical and statistical techniques useful for modelling and analyzing the problems in which several independent variables influence a dependent variable or response. The mathematical models commonly used are represented by:where Y is the machining response, ϕ is the response function and S, f , α, r are milling variables and ∈is the error which is normally distributed about the observed response Y with zero mean.The relationship between surface roughness and other independent variables can be represented as follows，where C is a constant and a, b, c and d are exponents.To facilitate the determination of constants and exponents, this mathematical model will have to be linearized by performing a logarithmic transformation as follows:The constants and exponents C, a, b, c and d can be determined by the method of least squares. The first order linear model, developed from the above functional relationship using least squares method, can be represented as follows:where Y1 is the estimated response based on the first-order equation, Y is the measured surface roughness on a logarithmic scale, x0 = 1 (dummy variable), x1, x2, x3 and x4 are logarithmic transformations of cutting speed, feed rate, radial rake angle and nose radiusrespectively, ∈is the experimental error and b values are the estimates of corresponding parameters.The general second order polynomial response is as given below:where Y2 is the estimated response based on the second order equation. The parameters, i.e. b0, b1, b2, b3, b4, b12, b23, b14, etc. are to be estimated by the method of least squares. Validity of the selected model used for optimizing the process parameters has been tested with the help of statistical tests, such as F-test, chi square test, etc. [10].3.2 Optimization using genetic algorithmsMost of the researchers have used traditional optimization techniques for solving machining problems. The traditional methods of optimization and search do not fare well over a broad spectrum of problem domains. Traditional techniques are not efficient when the practical search space is too large. These algorithms are not robust. They are inclined to obtain a local optimal solution. Numerous constraints and number of passes make the machining optimization problem more complicated. So, it was decided to employ genetic algorithms as an optimization technique. GA come under the class of non-traditional search and optimization techniques. GA are different from traditional optimization techniques in the following ways:1.GA work with a coding of the parameter set, not the parameter themselves.2.GA search from a population of points and not a single point.3.GA use information of fitness function, not derivatives or other auxiliary knowledge.4.GA use probabilistic transition rules not deterministic rules.5.It is very likely that the expected GA solution will be the global solution.Genetic algorithms (GA) form a class of adaptive heuristics based on principles derived from the dynamics of natural population genetics. The searching process simulates the natural evaluation of biological creatures and turns out to be an intelligent exploitation of a random search. The mechanics of a GA is simple, involving copying of binary strings. Simplicity of operation and computational efficiency are the two main attractions of the genetic algorithmic approach. The computations are carried out in three stages to get a result in one generation or iteration. The three stages are reproduction, crossover and mutation.In order to use GA to solve any problem, the variable is typically encoded into a string (binary coding) or chromosome structure which represents a possible solution to the given problem. GA begin with a population of strings (individuals) created at random. The fitness of each individual string is evaluated with respect to the given objective function. Then this initial population is operated on by three main operators – reproduction cross over and mutation– to create, hopefully, a better population. Highly fit individuals or solutions are given theopportunity to reproduce by exchanging pieces of their genetic information, in the crossover procedure, with other highly fit individuals. This produces new “offspring” solutions, which share some characteristics taken from both the parents. Mutation is often applied after crossover by altering some genes (i.e. bits) in the offspring. The offspring can either replace the whole population (generational approach) or replace less fit individuals (steady state approach). This new population is further evaluated and tested for some termination criteria. The reproduction-cross over mutation- evaluation cycle is repeated until the termination criteria are met.4 Experimental detailsFor developing models on the basis of experimental data, careful planning of experimentation is essential. The factors considered for experimentation and analysis were cutting speed, feed rate, radial rake angle and nose radius.4.1 Experimental designThe design of experimentation has a major affect on the number of experiments needed. Therefore it is essential to have a well designed set of experiments. The range of values of each factor was set at three different levels, namely low, medium and high as shown in Table 1. Based on this, a total number of 81 experiments (full factorial design), each having a combination of different levels of factors, as shown in Table 2, were carried out.The variables were coded by taking into account the capacity and limiting cutting conditions of the milling machine. The coded values of variables, to be used in Eqs. 3 and 4, were obtained from the following transforming equations:where x1 is the coded value of cutting speed (S), x2 is the coded value of the feed rate ( f ), x3 is the coded value of radial rake angle(α) and x4 is the coded value of nose radius (r).4.2 ExperimentationA high precision ‘Rambaudi Rammatic 500’ CNC milling machine, with a vertical milling head, was used for experimentation. The control system is a CNC FIDIA-12 compact. The cutting tools, used for the experimentation, were solid coated carbide end mill cutters of different radial rake angles and nose radii (WIDIA: DIA20 X FL38 X OAL 102 MM). The tools are coated with TiAlN coating. The hardness, density and transverse rupture strength are 1570 HV 30, 14.5 gm/cm3 and 3800 N/mm2 respectively.AISI 1045 steel specimens of 100×75 mm and 20 mm thickness were used in the present study. All the specimens were annealed, by holding them at 850 ◦C for one hour and then cooling them in a furnace. The chemical analysis of specimens is presented in Table 3. Thehardness of the workpiece material is 170 BHN. All the experiments were carried out at a constant axial depth of cut of 20 mm and a radial depth of cut of 1 mm. The surface roughness (response) was measured with Talysurf-6 at a 0.8 mm cut-off value. An average of four measurements was used as a response value.5 Results and discussionThe influences of cutting speed, feed rate, radial rake angle and nose radius have been assessed by conducting experiments. The variation of machining response with respect to the variables was shown graphically in Fig. 1. It is seen from these figures that of the four dependent parameters, radial rake angle has definite influence on the roughness of the surface machined using an end mill cutter. It is felt that the prominent influence of radial rake angle on the surface generation could be due to the fact that any change in the radial rake angle changes the sharpness of the cutting edge on the periphery, i.e changes the contact length between the chip and workpiece surface. Also it is evident from the plots that as the radial rake angle changes from 4◦to 16◦, the surface roughness decreases and then increases. Therefore, it may be concluded here that the radial rake angle in the range of 4◦to 10◦would give a better surface finish. Figure 1 also shows that the surface roughness decreases first and then increases with the increase in the nose radius. This shows that there is a scope for finding the optimum value of the radial rake angle and nose radius for obtaining the best possible quality of the surface. It was also found that the surface roughness decreases with an increase in cutting speed and increases as feed rate increases. It could also be observed that the surface roughness was a minimum at the 250 m/min speed, 200 mm/min feed rate, 10◦radial rake angle and 0.8 mm nose radius. In order to understand the process better, the experimental results can be used to develop mathematical models using RSM. In this work, a commercially available mathematical software package (MATLAB) was used for the computation of the regression of constants and exponents.5.1 The roughness modelUsing experimental results, empirical equations have been obtained to estimate surface roughness with the significant parameters considered for the experimentation i.e. cutting speed, feed rate, radial rake angle and nose radius. The first order model obtained from the above functional relationship using the RSM method is as follows:The transformed equation of surface roughness prediction is as follows:Equation 10 is derived from Eq. 9 by substituting the coded values of x1, x2, x3 and x4 in termsof ln s, ln f , lnαand ln r. The analysis of the variance (ANOV A) and the F-ratio test have been performed to justify the accuracy of the fit for the mathematical model. Since the calculated values of the F-ratio are less than the standard values of the F-ratio for surface roughness as shown in Table 4, the model is adequate at 99% confidence level to represent the relationship between the machining response and the considered machining parameters of the end milling process.The multiple regression coefficient of the first order model was found to be 0.5839. This shows that the first order model can explain the variation in surface roughness to the extent of 58.39%. As the first order model has low predictability, the second order model has been developed to see whether it can represent better or not.The second order surface roughness model thus developed is as given below:where Y2 is the estimated response of the surface roughness on a logarithmic scale, x1, x2, x3 and x4 are the logarithmic transformation of speed, feed, radial rake angle and nose radius. The data of analysis of variance for the second order surface roughness model is shown in Table 5.Since F cal is greater than F0.01, there is a definite relationship between the response variable and independent variable at 99% confidence level. The multiple regression coefficient of the second order model was found to be 0.9596. On the basis of the multiple regression coefficient (R2), it can be concluded that the second order model was adequate to represent this process. Hence the second order model was considered as an objective function for optimization using genetic algorithms. This second order model was also validated using the chi square test. The calculated chi square value of the model was 0.1493 and them tabulated value at χ2 0.005 is 52.34, as shown in Table 6, which indicates that 99.5% of the variability in surface roughness was explained by this model.Using the second order model, the surface roughness of the components produced by end milling can be estimated with reasonable accuracy. This model would be optimized using genetic algorithms (GA).5.2 The optimization of end millingOptimization of machining parameters not only increases the utility for machining economics, but also the product quality toa great extent. In this context an effort has been made to estimate the optimum tool geometry and machining conditions to produce the best possible surface quality within the constraints.The constrained optimization problem is stated as follows: Minimize Ra using the model given here:where xil and xiu are the upper and lower bounds of process variables xi and x1, x2, x3, x4 are logarithmic transformation of cutting speed, feed, radial rake angle and nose radius.The GA code was developed using MATLAB. This approach makes a binary coding system to represent the variables cutting speed (S), feed rate ( f ), radial rake angle (α) and nose radius (r), i.e. each of these variables is represented by a ten bit binary equivalent, limiting the total string length to 40. It is known as a chromosome. The variables are represented as genes (substrings) in the chromosome. The randomly generated 20 such chromosomes (population size is 20), fulfilling the constraints on the variables, are taken in each generation. The first generation is called the initial population. Once the coding of the variables has been done, then the actual decoded values for the variables are estimated using the following formula: where xi is the actual decoded value of the cutting speed, feed rate, radial rake angle and nose radius, x(L) i is the lower limit and x(U) i is the upper limit and li is the substring length, which is equal to ten in this case.Using the present generation of 20 chromosomes, fitness values are calculated by the following transformation:where f(x) is the fitness function and Ra is the objective function.Out of these 20 fitness values, four are chosen using the roulette-wheel selection scheme. The chromosomes corresponding to these four fitness values are taken as parents. Then the crossover and mutation reproduction methods are applied to generate 20 new chromosomes for the next generation. This processof generating the new population from the old population is called one generation. Many such generations are run till the maximum number of generations is met or the average of four selected fitness values in each generation becomes steady. This ensures that the optimization of all the variables (cutting speed, feed rate, radial rake angle and nose radius) is carried out simultaneously. The final statistics are displayed at the end of all iterations. In order to optimize the present problem using GA, the following parameters have been selected to obtain the best possible solution with the least computational effort: Table 7 shows some of the minimum values of the surface roughness predicted by the GA program with respect to input machining ranges, and Table 8 shows the optimum machining conditions for the corresponding minimum values of the surface roughness shown in Table 7. The MRR given in Table 8 was calculated bywhere f is the table feed (mm/min), aa is the axial depth of cut (20 mm) and ar is the radial depth of cut (1 mm).It can be concluded from the optimization results of the GA program that it is possible toselect a combination of cutting speed, feed rate, radial rake angle and nose radius for achieving the best possible surface finish giving a reasonably good material removal rate. This GA program provides optimum machining conditions for the corresponding given minimum values of the surface roughness. The application of the genetic algorithmic approach to obtain optimal machining conditions will be quite useful at the computer aided process planning (CAPP) stage in the production of high quality goods with tight tolerances by a variety of machining operations, and in the adaptive control of automated machine tools. With the known boundaries of surface roughness and machining conditions, machining could be performed with a relatively high rate of success with the selected machining conditions.6 ConclusionsThe investigations of this study indicate that the parameters cutting speed, feed, radial rake angle and nose radius are the primary actors influencing the surface roughness of medium carbon steel uring end milling. The approach presented in this paper provides n impetus to develop analytical models, based on experimental results for obtaining a surface roughness model using the response surface methodology. By incorporating the cutter geometry in the model, the validity of the model has been enhanced. The optimization of this model using genetic algorithms has resulted in a fairly useful method of obtaining machining parameters in order to obtain the best possible surface quality.中文翻译选择最佳工具，几何形状和切削条件利用表面粗糙度预测模型端铣摘要：刀具几何形状对工件表面质量产生的影响是人所共知的，因此，任何成型面端铣设计应包括刀具的几何形状。
中英文中英文文献翻译-汽车发动机凸轮轴
Automotive engine camshaftBrief introductionThe camshaft is a part of the piston engine. Its role is to control the opening and closing operation of the valve. Although the camshaft rotational speed in a four-stroke engine is a half of the crankshaft (the same as the camshaft rotational speed in a two-stroke engine with the crankshaft), but usually it is still very high speed, but also need to withstand the large torque, so the design right demanding camshaft in terms of strength and support material is generally a special cast iron, occasionally using forgings. Valve motion law related to engine power and operation characteristics, the design in the design process of the engine camshaft occupies a very important position.StructureThe main body of the camshaft is the same as the one with the cylinder length of the cylindrical rod. The above sets have several cam for driving the valve. One end of the camshaft camshaft bearing support and the other end is connected to the drive wheels.Cam side was egg-shaped. The design aims to ensure the the cylinder sufficient air intake and exhaust, specifically, within the shortest possible time to complete the valve opening and closing movements. In addition, taking into account the durability of the engine and the smoothness of operation, the valve can not be generated due to the deceleration process of opening and closing movements too much too large the impact of serious wear and tear of the valve, otherwise it will cause an increase in noise or other serious consequences. Therefore, the cam and the power of the engine torque output as well as the operation of the ride there is a direct relationship.Generally inline engine, a cam corresponding to a valve V-type engine or horizontal opposed type engine, every two valves share a cam. The rotary engine the valveless with gas engine because of its special structure, does not need to camPositionIn the long period of time, the bottom-mounted camshaft in an internal combustion engine is most common. Typically such engines, the valve is located in the top of the engine camshaft machine, i.e., so-called the OHV (Over Head V alve, OHV) engines. Usually camshaft located on the side of the crankcase, through the gas distribution agencies (such as tappet, push rod, rocker, etc.) valve control. Bottom-mounted camshaft general also called side-mounted camshaft. Far distance valve, and each cylinder is usually only two valves in such an engine camshaft, so the speed is usually slower, ride comfort is poor, the output power is also relatively low. However, the engine output torque and low-speed performance of this structure is relatively good, relatively simple structure and easy maintenance.Now most of the production car's engine is equipped with overhead camshaft. The overhead camshafts structure closer to the camshaft valve, to reduce the kinetic energy of the waste causedby the bottom-mounted camshaft due to the larger distance between the camshaft and the valve shuttle. Overhead camshaft of the engine valve opening and closing action is relatively rapid, and hence higher speed, and the smooth running is also better. The engine of the the overhead camshafts structure appeared earlier the SOHC (Single Over Head Cam, overhead single camshaft) engine. This engine is only installed at the top of a camshaft, and therefore generally only two to three valves of each cylinder (the intake air a to two exhaust), the high-speed performance has been limited. Technology updates DOHC (Double Over Head Cam, double overhead camshaft) engine, this engine with a two camshafts per cylinder can be installed four to five valves (intake two to three, Pai gas two), high-speed performance significantly improved, but at the same time the low-speed performance will be affected to some degree, the structure will be complicated and difficult to repair.ClassificationAccording to the the camshaft number of how many, can be divided into single overhead camshaft (SOHC) and double overhead camshaft (DOHC), two kinds. The single overhead camshaft camshaft is only one camshaft, double overhead camshaft is two, this is too straightforward explanation.The single overhead camshaft with a camshaft in the cylinder head, direct drive into the exhaust valve, it has a simple structure, suitable for high-speed engine. Generally used in the past side camshaft, the camshaft in the cylinder side, is driven directly by a timing gear. The valve lifter to the rotation of the camshaft is converted into reciprocating motion of the valve must be used to transfer power. Thus, more parts of the reciprocating motion, the inertial mass, is not conducive to high-speed movement of the engine. Moreover, the slender tappet has a certain degree of flexibility, prone to vibration, accelerated component wear, even the valve control is lost.DOHC cylinder head equipped with two camshafts, one is used to drive the intake valve, the other for driving the exhaust valve. Double overhead camshaft camshaft and valve spring design less demanding, especially for the hemispherical combustion chamber of the valve V-shaped configuration, but also facilitate and used in conjunction with four-valve gas distribution agencies.FaultCamshaft common faults including abnormal wear and tear, abnormal wear of the symptoms often first appear before the occurrence of abnormal sound as well as fracture, abnormal sound and fracture.(1) Camshaft almost at the end of the engine lubrication system, lubrication situation is not optimistic. If the oil pump is too long and so insufficient oil pressure or the lubricants Road blockage caused by lubricating oil can not reach the camshaft bearing cap fastening bolts tightening torque caused by excessive oil can not enter the the camshaft gap will causing abnormal wear of the camshaft.(2) the abnormal wear of the camshaft causes the gap increases between the camshaft bearing, the camshaft movement occurs when the axial displacement, resulting in abnormal noise. Abnormal wear will lead to increased gap between the drive cam with hydraulic tappets, camcombined with hydraulic tappets will collide, resulting in abnormal noise.(3) camshaft sometimes fracture and other serious fault, common causes of hydraulic tappet cracked or severely worn, serious poor lubrication the camshaft poor quality and camshaft timing gear rupture.(4) In some cases, the failure of the camshaft is man-made causes, in particular the maintenance of the engine camshaft not correct disassembly. Such as demolition of the camshaft bearing caps with a hammer strength knocking or prying with a screwdriver, or install the bearing cap installed the wrong position does not match the result in the bearing cap and bearing, or bearing cover the fastening bolt tightening torque is too large. Install bearing cap should pay attention to the direction of the arrow and the position number marked on the surface of the bearing cap, and in strict accordance with the provisions of torque using the torque wrench tighten the bearing cap fastening bolts.RefitIn order to enhance the power of the engine, some converted stores a modified camshaft engine face lift high angle camshaft (Hi-camshaft CAM) is a common form of modified method. This modification operation is not complicated, but because of the lack of understanding of some modification cam on the camshaft angle and works so that the modified effect is not obvious even lead to the deterioration of the performance of the engine.High angle camshaft relative to ordinary camshaft cam angle of about 240°, high angle camshaft cam angle can often reach over 280°. The large angle of the camshaft can extend the valve open time, increase the valve lift, the intake valve and the exhaust valve open as early and late off, so that more air into the cylinder, in order to improve the engine, the power of the high speed output. Should choose for civilian vehicles, modified cam camshaft angle 278, will be a significant increase in working an angle greater than 278°camshaft valve overlap angle, so that the power of the engine high speed improve a lot, but engine cylinder seal is not good at low speed and cause the idling serious jitter or even turn off, so that the vehicle can not adapt to everyday use, and can only be used for competition purposes.Production technologyThe camshaft is one of the key parts of the engine, the hardness of the camshaft peach apical and white layer depth is to determine the key technical indicators camshaft life and engine efficiency. , Should be considered to ensure that the cam has a sufficiently high hardness and a fairly deep white layer premise journal does not appear high carbide, so that it has a better cutting performance.Currently, the main method of domestic and foreign production camshaft: steel forging blank by cutting the cam peach tip martensitic layer formed some of the high-frequency quenching process. The end of the 1970s, Germany and France have developed a new camshaft argon arc remelting process; hardened cast iron camshaft otherwise dominated by the United States; chilled cast iron camshaft mainly to Japan and France; well cam parts of the Cr-Mn-Mo alloy coatings casting surface alloying production.汽车发动机凸轮轴简介凸轮轴是活塞发动机里的一个部件。
毕业设计论文外文文献翻译汽车专业汽修点火系统中英文对照
Ignition SystemThe purpose of the ignition system is to create a spark that will ignite the fuel-air mixture in the cylinder of an engine. It must do this at exactly the right instant and do it at the rate of up to several thousand times per minute for each cylinder in the engine. If the timing of that spark is off by a small fraction of a second, the engine will run poorly or not run at all.The ignition system sends an extremely high voltage to the spark plug in each cylinder when the piston is at the top of its compression stroke. The tip of each spark plug contains a gap that the voltage must jump across in order to reach ground. That is where the spark occurs.The voltage that is available to the spark plug is somewhere between 20,000 volts and 50,000 volts or better. The job of the ignition system is to produce that high voltage from a 12 volt source and get it to each cylinder in a specific order, at exactly the right time.The ignition system has two tasks to perform. First, it must create a voltage high enough (20,000+) to across the gap of a spark plug, thus creating a spark strong enough to ignite the air/fuel mixture for combustion. Second, it must control the timing of that the spark so it occurs at the exact right time and send it to the correct cylinder.The ignition system is divided into two sections, the primary circuit and the secondary circuit. The low voltage primary circuit operates at battery voltage (12 to 14.5 volts) and is responsible for generating the signal to fire the spark plug at the exact right time and sending that signal to the ignition coil. The ignition coil is the component that converts the 12 volt signal into the high 20,000+ volt charge. Once the voltage is stepped up, it goes to the secondary circuit which then directs the charge to the correct spark plug at the right time.The BasicsBefore we begin this discussion, let’’s talk a bit about electricity in general. I know that this is Before we begin this discussion, letbasic stuff, but there was a time that you didn’’t know about this and there are people who need basic stuff, but there was a time that you didnto know the basics so that they could make sense of what follows.All automobiles work on DC (Direct Current). This means that current move in one direction, form the positive battery terminal to the negative battery terminal. In the case of the automobile, the negative battery terminal is connected by a heavy cable directly to the body and the engine block of the vehicle. The body and any metal component in contact with it is called the ground. This means that a circuit that needs to send current back to the negative side of the battery can be connected to any part of the vehicle’’s metal body or the metal engine block.be connected to any part of the vehicleA good example to see how this works is the headlight circuit. The headlight circuit consists of a wire that goes from the positive battery terminal to the headlight switch. Another wire goes from the headlight switch to one of two terminals on the headlight bulb. Finally, a third wire goes from a second terminal on the bulb to the metal body of car. When you switch the headlight on, you are connecting the wire from the battery with the wire to the headlamps allowing battery current to go directly to the headlamp bulbs. Electricity passes through the filaments inside the bulb, then out the other wire to the metal body. From there, the current goes back to the negative terminal of the battery completing the circuit. Once the current is flowing through this circuit, the filament inside the headlamp gets hot and glows brightly. Let there be light.Now, back to the ignition system, the basic principle of the electrical spark ignition system has not changed for over 75 years. What has changed is the method by which the spark is created and how it is distribute.Currently, there are three distinct types of ignition system. The mechanical ignition systemwas used prior to 1975. It was mechanical and electrical and used no electronics. By understanding these early system, it will be easier to understand the new electronic andcomputer controlled ignition system, so don’’t skip over it. The electronic ignition system started computer controlled ignition system, so donfinding its way to production vehicles during the early 70s and became popular when better control and improved reliability became important with the advent of emission controls. Finally, the distributor less ignition system became available in the mid 80s. This system was always computer controlled and contained no moving parts, so reliability was greatly improved. Most of these systems required no maintenance except replacing the spark plugs at intervals from 60,000 to over 100,000 miles.Let’’s take a detailed look at each system and see how they work.LetThe Mechanical Ignition SystemThe distributor is the nerve center of the mechanical ignition system and has two tasks to perform. First, it is responsible for triggering coil to generate a spark at the precise instant that it is required (which varies depending how fast the engine is turning and how much load it is under). Second, the distributor is responsible for directing that spark to the proper cylinder (which is why it is called a distributor).The circuit that powers the ignition system is simple and straight forward. When you insert the key in the ignition switch and turn the key to the Run position, you are sending current from the battery through a wire directly to the positive (+) side of the ignition coil. Inside the coil is a series of copper windings that loop around the coil over a hundred times before exiting out the negative (-) side of the coil. From there, a wire takes this current over to the distributor and is connected to a special on/off switch, called the points. When the points are closed, this current goes directly to ground. When current flows from the ignition switch, through the windings in the coil, then to ground, it builds a strong magnetic field inside the coil.The points are made up of a fixed contact point that is fastened to a plate inside the distributor, and a movable contact point mounted on the end of a spring loaded arm. The movable point rides on a 4, 6, or 8 lobe cam (depending on the number of cylinder in the engine) that is mounted on a rotating shaft inside the distributor. This distributor cam rotates in time with the engine, making one complete revolution for every two revolutions of the engine. As it rotates, the cam pushes the points open and closed. Every time the points open, the flow of current is interrupted through the coil, thereby collapsing the magnetic field and releasing a high voltage surge through the secondary coil windings. This voltage surge goes out the top of the coil and through the high-tension coil wire.Now, we have the voltage necessary to fire the spark plug, but we still have to get it to the correct cylinder. The coil wire goes from the coil directly to the distributor cap. Under the cap is a rotor that is mounted on top of the rotating shaft. The rotor has a metal strip on the top that is in constant contact with the center terminal of the distributor cap. It receives the high voltage surge from the coil wire and sends it to the other end of the rotor which rotates past each spark plug terminal inside the cap. As the rotor turns on the shaft, it sends the voltage to the correct spark plug wire, which in turn sends it to the spark plug. The voltage enters the spark plug at the terminal at the top and travels down the core until it reaches the tip. It then jumps across the tip of the spark plug, creating a spark suitable to ignite the fuel-air mixture inside that cylinder. The description I just provided is the simplified version, but should be helpful to visualize the process, but we left out a few things that make up this type of ignition system. For instance, we didn’’t talk about the condenser that is connected to the point, nor did we talk about the system didnto advance the timing. Let’’s take a look at each section and explore it in more detail.to advance the timing. LetThe Ignition SwitchThere are two separate circuits that go from the ignition switch to the coil. One circuit runs through a resistor in order to step down the voltage about 15% in order to protect the points from premature wear. The other circuit sends full battery voltage to the coil. The only time this circuit is used is during cranking. Since the starter draws a considerable amount of current to crank the engine, additional voltage is needed to power the coil. So when the key is turned to the spring-loaded start position, full battery voltage is used. As soon as the engine is running, the driver releases the key to the run position which directs current through the primary resistor to the coil.On some vehicles, the primary resistor is mounted on the firewall and is easy to replace if it fails. On other vehicles, most notably vehicles manufactured by GM, the primary resister is a special resister wire and is bundled in the wiring harness with other wires, making it more difficult to replace, but also more durable.The DistributorWhen you remove the distributor cap from the top of the distributor, you will see the points and condenser. The condenser is a simple capacitor that can store a small amount of current. When the points begin to open the current, flowing through the points looks for an alternative path to ground. If the condenser were not there, it would try to jump across the gap of the point as they begin to open. If this were allowed to happen, the points would quickly burn up and you would hear heavy static on the car radio. To prevent this, the condenser acts like a path to ground. It really is not, but by the time the condenser is saturated, the points are too far apart for the small amount of voltage to jump across the wide point gap. Since the arcing across the opening points is eliminated, the points last longer and there is no static on the radio from point arcing.The points require periodic adjustments in order to keep the engine running at peek efficiency. This is because there is a rubbing block on the points that is in contact with the cam and this rubbing block wears out over time changing he point gap. There are two ways that the points can be measured to see if they need an adjustment. One way is by measuring the gap between the open points when the rubbing block is on the high point of the cam. The other way is by measuring the dwell electrically. The dwell is the amount, in degrees of cam rotation that the points stay closed.On some vehicles, points are adjusted with the engine off and the distributor cap removed. A mechanic will loosen the fixed point and move it slightly, then retighten it in the correct position using a feeler gauge to measure the gap. On other vehicles, most notably GM cars, there is a window in the distributor where a mechanic can insert a tool and adjust the points using a dwell meter while the engine is running. Measuring dwell is much more accurate than setting the points with a feeler gauge.Points have a life expectancy of about 10,000 miles at which time have to be replaced. This is done during a routine major tune up, points, condenser, and the spark plugs are replaced, the timing is set and the carburetor is adjusted. In some cases, to keep the engine running efficiently, a minor tune up would be performed at 5,000 mile increments to adjust the point and reset the timing.Ignition CoilThe ignition coil is nothing more that an electrical transformer. It contains both primary and secondary winding circuit. The coil primary winding contains 100 to 150 turns of heavy copper wire. This wire must be insulated so that the voltage does not jump from loop to loop, shortingit out. If this happened, it could not create the primary magnetic field that is required. The primary circuit wire goes into the coil through the positive terminal, loops around the primary windings, then exits through the negative terminal.The coil secondary winding circuit contains 15,000 to 30,000 turns of fine copper wire, which also must be insulated from each other. The secondary windings sit inside the loops of the primary windings. To further increase the coils magnetic field the windings are wrapped around a soft iron core. To withstand the heat of the current flow, the coil is filled with oil which helps keep it cool.The ignition coil is the heart of the ignition system. As current flows through the coil a strong magnetic field is build up. When the current is shut off, the collapse of this magnetic field to the secondary windings induces a high voltage which is released through the large center terminal. This voltage is then directed to the spark plugs through the distributor.Ignition Timing The timing is set by loosening a hold-down screw and rotating the body of the distributor. Since the spark is triggered at the exact instant that the points begin to open, rotating the distributor body (which the point are mounted on) will change the relationship between the position and the position of the distributor cam, which is on the shaft that is geared to the engine rotation.While setting the initial or base timing is important, for an engine to run properly, the timing needs to change depending on the speed of the engine and the load that it is under. If we can move the plate that the points are mounted on, or we could change the position of the distributor cam in relation to the gear that drives it, we can alter the timing dynamically to suit the needs of the engine.Ignition Wires These cables are designed to handle 20,000 to more than 50,000 volts, enough voltage to toss you across the room if you were to be exposed to it. The job of the spark plug wires is to get that enormous power to the spark plug without leaking out. Spark plug wires have to endure the heat of a running engine as well as the extreme changes in the weather. In order to do their job, spark plug wires are fairly thick, with most of that thickness devoted to insulation with a very thin conductor running down the center. Eventually, the insulation will succumb to the elements and the heat of the engine and begins to harden, crack, dry out, or otherwise break down. When that happens, they will not be able to deliver the necessary voltage to the spark plug and a misfire will occur. That is what is meant by “Not running on all cylinders cylinders””. To correct this problem, the spark plug wires would have to be replaced.Spark plug wires are routed around the engine very carefully. Plastic clips are often used to keep the wires separated so that they do not touch together. This is not always necessary, especially when the wires are new, but as they age, they can begin to leak and crossfire on damp days causing hard starting or a rough running engine.Spark plug wires go from the distributor cap to the spark plugs in a very specific order. This is called the is called the ““firing order firing order”” and is part of the engine design. Each spark plug must only fire at the end of the compression stroke. Each cylinder has a compression stroke at a different time, so it is important for the individual spark plug wire to be routed to the correct cylinder.For instance, a popular V8 engine firing order is 1, 8, 4, 3, 6, 5, 7, 2. The cylinders are numbered from the front to the rear with cylinder #1 on the front-left of the engine. So the cylinders on the left side of the engine are numbered 1, 3, 5, 7while the right side are numbered 2, 4, 6, 8. On some engine, the right bank is 1, 2, 3, 4 while the left bank is 5, 6, 7, 8. A repairmanual will tell you the correct firing order and cylinder layout for a particular engine.The next thing we need to know is what direction the distributor is rotating in, clockwise or counter-clockwise, and which terminal on the distributor caps that #1 cylinder is located. Once we have this information, we can begin routing the spark plug wires.If the wires are installed incorrectly, the engine may backfire, or at the very least, not run on all cylinders. It is very important that the wires are installed correctly.Spark PlugsThe ignition system system’’s sole reason for being is to service the spark plug. It must provide sufficient voltage to jump the gap at the tip of the spark plug and do it at the exact right time, reliably on the order of thousands of times per minute for each spark plug in the engine.The modern spark plug is designed to last many thousands of miles before it requires replacement. These electrical wonders come in many configurations and heat ranges to work properly in a given engine. The heat range of a spark plug dictates whether it will be hot enough to burn off any residue that collects on the tip, but not so hot that it will cause pre-ignition in the engine. Pre-ignition is caused when a spark plug is so hot, that it begins to glow and ignite the fuel-air mixture prematurely, before the spark. Most spark plugs contain a resistor to suppress radio interference. The gap on a spark plug is also important and must be set before the spark plug is installed in the engine. If the gap is too wide, there may not be enough voltage to jump the gap, causing a misfire. If the gap is too small, the spark may be inadequate to ignite a lean fuel-air mixture also causing a misfire.The Electronic Ignition SystemThis section will describe the main differences between the early point & condenser systems and the newer electronic systems. If you are not familiar with the way an ignition system works in general, I strongly recommend that you first read the previous section The Mechanical Ignition System.In the electronic ignition system, the points and condenser were replaced by electronics. On these systems, there were several methods used to replace the points and condenser in order to trigger the coil to fire. One method used a metal wheel with teeth, usually one for each cylinder. This is called an armature. A magnetic pickup coil senses when a tooth passes and sends a signal to the control module to fire the coil.Other systems used an electric eye with a shutter wheel to send a signal to the electronics that it was time to trigger the coil to fire. These systems still need to have the initial timing adjusted by rotating the distributor housing.The advantage of this system, aside from the fact that it is maintenance free, is that the control module can handle much higher primary voltage than the mechanical point. V control module can handle much higher primary voltage than the mechanical point. Voltage can oltage can even be stepped up before sending it to the coil, so the coil can create a much hotter spark, on the order of 50,000 volts that is common with the mechanical systems. These systems only have a single wire from the ignition switch to the coil since a primary resistor is not longer needed. On some vehicles, this control module was mounted inside the distributor where the points used to be mounted. On other designs, the control module was mounted outside the distributor with external wiring to connect it to the pickup coil. On many General Motors engines, the control module was inside the distributor and the coil was mounted on top of the distributor for a one piece unitized ignition system. GM called it high energy ignition or HEI for short.The higher voltages that these systems provided allow the use of a much wider gap on the spark plugs for a longer, fatter spark. This larger sparks also allowed a leaner mixture for betterfuel economy and still insure a smooth running engine.The early electronic systems had limited or no computing power, so timing still a centrifugal and vacuum advance built into the distributor.On some of the later systems, the inside of the distributor is empty and all triggering is performed by a sensor that watches a notched wheel connected to either the crankshaft or the camshaft. These devices are called crankshaft position sensor or camshaft position sensor. In these systems, the job of the distributor is solely to distribute the spark to the correct cylinder through the distributor cap and rotor. The computer handles the timing and any timing advance necessary for the smooth running of the engine.The Distributor Ignition SystemNewer automobiles have evolved from a mechanical system (distributor) to a completely solid state electronic system with no moving parts. These systems are completely controlled by the on-board computer. In place of the distributor, there are multiple coils that each serves one or two spark plugs. A typical 6 cylinder engine has 3 coils that are mounted together in a coil pack””. A spark plug wire comes out of each side of the individual coil and goes to the “packappropriate spark plug. The coil fires both spark plugs at the same time. One spark plug fires on the compression stroke igniting the fuel-air mixture to produce power while the other spark plug fires on the exhaust stroke and does nothing. On some vehicles, there is an individual coil for each cylinder mounted directly on top of the spark plug. This design completely eliminates the high tension spark plug wires for even better reliability. Most of these systems use spark plugs that are designed to last over 100,000 miles, which cuts down on maintenance costs.参考文献：[1] 王欲进,张红伟汽车专业英语[M]. 北京：北京大学出版社，中国林业出版社，2007.8，55—67点火系统点火系统的作用是产生点燃发动机气缸里可燃混合物的火花。
外文文献翻译、中英文翻译--冷锻技术的发展现状与趋势
附录1:翻译（汉）冷锻技术的发展现状与趋势摘要：冷锻技术是一种精密塑性成形工艺，具有切削加工不可比拟的优点，广泛应用于各种机械产品关键零部件的制造。
本文从冷锻零件的形状、材料、工艺革新、生产率、数值模拟技术和数字化/智能化设计技术应用、以及优化技术几个方面综合论述了冷锻技术的发展现状与趋势。
关键词：冷锻，工艺/模具设计，数值模拟，基于知识的工艺设计，设计优化。
冷锻工艺是一种精密塑性成形技术，具有切削加工无可比拟的优点，如制品的机械性能好，生产率高和材料利用率高，特别适合于大批量生产，而且可以作为最终产品的制造方法（net-shape forming），在交通运输工具、航空航天和机床工业等行业具有广泛的应用。
当前汽车工业、摩托车工业和机床工业的飞速发展，为冷锻这一传统的技术的发展提供了原动力，例如，我国1999年摩托车的全国总产量就有1126万多辆，而根据2000年的初步估计，我国汽车的总需求量到2005年将达到330万辆，其中轿车130-140万辆，仅汽车行业的锻件需求在50-60万吨以上。
冷锻技术在我国的起步虽然不算太晚，但发展速度与发达国家有很大的差距。
到目前为止，我国生产的轿车上的冷锻件重量不足20Kg，相当于发达国家的一半，开发潜力很大。
加强冷锻技术开发与推广应用是我国目前的一项紧迫任务。
1、冷锻件的形状越来越复杂冷锻零件的形状越来越趋于复杂，由最初的阶梯轴、螺钉/螺母和导管等，发展到形状复杂的零件，如图1所示为不同尺寸的摩托车花键轴与花键套，花键轴的典型工艺为：正挤压杆部-镦粗中间头部分-挤压花键；花键套的主要工艺为：反挤压杯形件-冲底制成环型件-正挤压轴套。
如图2所示为汽车输出轴与输入轴，以及其他冷锻制品。
如图3所示为我国采用摆动碾压技术制成的各种汽车/摩托车用锥齿轮、螺旋锥齿轮和其他圆盘类零件，如图4所示为日本某公司生产的冷锻零件，图4所示的涡旋增压器，我国已经列入国家“十五”攻关项目。
汽车发动机外文翻译文献
汽车发动机外文翻译文献(文档含中英文对照即英文原文和中文翻译)AUTOMOTIVE ENGINE1 Engine Classification and Overall MechanicsThe automobile engines can be classified according to: (1) cycles, (2) cooling system, (3) fuel system, (4) ignition method, (5) valve arrangement, (6) cylinder arrangement, (7) engine speed.Engines used in automobiles are the internal combustion heat engines. The burning of gasoline inside the engine produces high pressure in the engine combustionchamber. This high pressure force piston to move, the movement is carried by connecting rods to the engine crankshaft. The crankshaft is thus made to rotate: the rotary motion is carried through the power train to the car wheels so that they rotate and the car moves.The engine requires four basic systems to run (Fig. 2-1). Diesel engines require three of these systems. They are fuel system, ignition system (except diesel), lubricating system and cooling system. However, three other related systems are also necessary. These are the exhaust system, the emission-control system, and the starting system. Each performs a basic job in making the engine run.Fig. 2-1 The engine construction2 Engine Operating PrinciplesFig. 2-2 Engine termsThe term “stroke” is used to describe the movement of the piston within the cylinder. The movement of the piston from its uppermost position (TDC, top dead center) to its lowest position (BDC, bottom dead center) is called a stroke. The operating cycle may require either two or four strokes to complete. Most automobile engines operate on the four stroke cycle (Fig. 2-2).In four-stroke engine, four strokes of the piston in the cylinder are required tocomplete one full operating cycle. Each stroke is named after the action. It performs intake, compression, power, and exhaust in that order (Fig. 2-3).Intake stroke Compression stroke Power stroke Exhaust strokeFig. 2-3 Four-stroke-cycle gasoline engine1. The intake strokeThe intake stroke begins with the piston near the top of its travel. As the piston begins its descent, the exhaust valve closes fully, the intake valve opens and the volume of the combustion chamber begins to increase, creating a vacuum. As the piston descends, an air/fuel mixture is drawn from the carburetor into the cylinder through the intake manifold. The intake stroke ends with the intake valve close just after the piston has begun its upstroke.2. Compression strokeAs the piston is moved up by the crankshaft from BDC, the intake valve closes. The air/fuel mixture is trapped in the cylinder above the piston. Future piston travel compresses the air/fuel mixture to approximately one-eighth of its original volume (approximately 8:1 compression ratio) when the piston has reached TDC. This completes the compression stroke.3. Power strokeAs the piston reaches TDC on the compression stroke, an electric spark is produced at the spark plug. The ignition system delivers a high-voltage surge of electricity to the spark plug to produce the spark. The spark ignites, or sets fire to, the air/fuel mixture. It now begins to burn very rapidly, and the cylinder pressure increases to as much as 3-5MPa or even more. This terrific push against the piston forces it downward, and a powerful impulse is transmitted through the connecting rod to the crankpin on the crankshaft. The crankshaft is rotated as the piston is pushed down by the pressure above it.4. Exhaust strokeAt the end of the power stroke the camshaft opens the exhaust valve, and the exhaust stroke begins. Remaining pressure in the cylinder, and upward movement of the piston, force the exhaust gases out of the cylinder. At the end of the exhaust stroke, the exhaust valve closes and the intake valve opens, repeating the entire cycle of events over and over again.3 Engine Block and Cylinder Head3.1 Engine BlockThe engine block is the basic frame of the engine. All other engine parts either fit inside it or fasten to it. It holds the cylinders, water jackets and oil galleries (Fig. 2-4). The engine block also holds the crankshaft, which fastens to the bottom of the block. The camshaft also fits in the block, except on overhead-cam engines. In most cars, this block is made of gray iron, or an alloy (mixture) of gray iron and other metals, such as nickel or chromium. Engine blocks are castings.Fig. 2-4 V6 engine blockSome engine blocks, especially those in smaller cars, are made of cast aluminum. This metal is much lighter than iron. However, iron wears better than aluminum. Therefore, the cylinders in most aluminum engines are lined with iron or steel sleeves. These sleeves are called cylinder sleeves. Some engine blocks are made entirely of aluminum.3.2 Cylinder SleevesCylinder sleeves are used in engine blocks to provide a hard wearing material for pistons and piston rings. The block can be made of one kind of iron that is light and easy to cast while the sleeves uses another that is better able to stand up wear and tear. There are two main types of sleeves: dry and wet (Fig. 2-5).Dry sleeve Wet sleeveFig. 2-5 Cylinder sleeve3.3 Cylinder HeadThe cylinder head fastens to the top of the block, just as a roof fits over a house. The underside forms the combustion chamber with the top of the piston. In-line engine of light vehicles have just one cylinder head for all cylinders; larger in-line engines can have two or more. Just as with engine blocks, cylinder heads can be made of cast iron or aluminum alloy. The cylinder head carries the valves, valve springs and the rockers on the rocker shaft, this part of valve gear being worked by the pushrods. Sometimes the camshaft is fitted directly into the cylinder head and operates on the valves without rockers. This is called an overhead camshaft arrangement.3.4 GasketThe cylinder head is attached to the block with high-tensile steel studs. The joint between the block and the head must be gas-tight so that none of the burning mixture can escape. This is achieved by using cylinder head gasket. Gaskets are also used to seal joins between the other parts, such as between the oil pan, manifolds, or water pump and the blocks.3.5 Oil PanThe oil pan is usually formed of pressed steel. The oil pan and the lower part of cylinder block together are called the crankcase; they enclose, or encase, thecrankshaft. The oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine. The oil drains off and run down into the pan. Thus, there is a constant circulation of oil between the pan and the working parts of the engine.4 Piston Assembly, piston rings , The piston pin ,Connecting Rods, Crankshafts And Flywheel4.1 PistonPiston rings and the piston pin are together called the piston assembly (Fig. 2-6).Fig. 2-6 Piston, piston rings and connecting rodThe piston is an important part of a four-stroke cycle engine. Most pistons are made fr om cast aluminum. The piston, through the connecting rod, transfers to the crankshaft the force created by the burning fuel mixture. This force turns the crankshaft.To withstand the heat of the combustion chamber, the piston must be strong. It also must be light, since it travels at high speeds as it moves up and down inside the cylind er. The piston is hollow. It is thick at the top where it takes the brunt of the heat and th e expansion force. It is thin at the bottom, where there is less heat. The top part of the piston is the head, or crown. The thin part is the skirt. Most pistons have three ring gro oves at the top. The sections between the ring grooves are called ring lands.4.2 piston ringspiston rings fit into ring grooves near the top of the piston. In simplest terms, pisto n rings are thin, circular pieces of metal that fit into grooves in the tops of the pistons. In modern engines, each piston has three rings. (Piston in older engines sometimeshad four rings, or even five.) The inside surface of the ring fits in the groove on the pi ston. The ring's outside surface presses against the cylinder walls. Rings provide the n eeded seal between the piston and the cylinder walls. That is, only the rings contact th e cylinder walls. The top two rings are to keep the gases in the cylinder and are called compression rings. The lower one prevents the oil splashed onto the cylinder bore fro m entering the combustion chamber, and is called an oil ring.4.3 The piston pinThe piston pin holds together the piston and the connecting rod. This pin fits into th e piston pin holes and into a hole in the top end of the connecting rod. The top end of t he rod is much smaller than the end that fits on the crankshaft. This small end fits insi de the bottom of the piston. The piston pin fits through one side of the piston, through the small end of the rod, and then through the other side of the piston. It holds the rod firmly in place in the center of the piston. Pins are made of high-strength steel and hav e a hollow center. Many pins are chrome-plated to help them wear better.A piston pin fits into a round hole in the piston. The piston pin joins the piston to the connecting ro d. The thick part of the piston that holds the piston pin is the pin boss.4.4 Connecting RodsThe connecting rod little end is connected to the piston pin. A bush made from a soft metal, such as bronze, is used for this joint. The lower end of the connecting rod f its the crankshaft journal. This is called the big end. For this big-end bearing, steel-ba cked lead or tin shell bearings are used. These are the same as those used for the main bearings. The split of the big end is sometimes at an angle, so that it is small enough t o be withdrawn through the cylinder bore. The connecting rod is made from forged all oy steel.4.5 CrankshaftsThe crankshaft is regarded as the “backbone” of the engine (Fig. 2-7). The crankshaft, in conjunction with the connecting rod, converts the reciprocating mo tion of the piston to the rotary motion needed to drive the vehicle. It is usually made fr om car-bon steel which is alloyed with a small proportion of nickel. The main bearing journals fit into the cylinder block and the big end journals align with the connecting rods. At the rear end of the crankshaft is attached the flywheel, and at the front end ar e the driving wheels for the timing gears, fan, cooling water and alternator. The throw of the crankshaft, i.e. the distance between the main journal and the big end centers, controls the length of the stroke. The stroke is double the throw, and the strokelength is the distance that the piston travels from TDC to BDC and vice versa.Fig. 2-7 The crankshaft4.6 FlywheelThe flywheel is made from carbon steel. It fits onto the rear of the crankshaft. As well as keeping the engine rotating between power strokes it also carries the clutch, w hich transmits the drive to the gearbox, and has the starter ring gear around its circumf erence. There is only one working stroke in four so a flywheel is needed to drive the c rankshaft during the time that the engine is performing the non-power strokes.5 Valve SystemFig. 2-8 Parts of the valve trainThe valve operating assembly includes the lifters or cam followers, pushrods, rocker arms and shafts or pivot, valve and springs etc. The purpose of this to open and close the intake and exhaust ports that lead to the combustion chambers as required (Fig. 2-8). Valve mechanisms vary depending on the camshaft location. When the camshaft is positioned in the engine block, valve lifters are mounted in the openings above the camshaft. Pushrods are connected from each valve lifter to a pivoted rocker arm mounted above each valve. A lobe on the camshaft is positioned directly below each valve lifter. A typical camshaft drive has a sprocket bolted to the end of the camshaft, and a matching sprocket is attached to the end of the crankshaft. Those two sprockets may be meshed together or surrounded a steel chain to have the camshaft drive. When the lower part of the camshaft lobe is rotating under the valve lifter, the valve spring holds the valve closed.汽车发动机1发动机的分类和整体力学汽车发动机可根据如下因素进行分类：（1）循环系统，（2）冷却系统，（3）燃油系统，（4）点火方式，（5）气门布置，（6）气缸排列，（7）发动机转速。
汽车车辆专业前桥外文文献翻译中英文翻译外文翻译
外文文献（一）外文原文Front axle general is in the front of the bus, also known as steering axle or drive bridge. Automobile front axle is the last important assemblies, including the steering knuckle kingpin, steering, front beam and other components. Front axle through the suspension and frame, used to support the ground and the frame between the vertical load, but also bear the braking force and lateral force and the force of torque, and ensure that the steering rotation right movement. The axle is connected with the frame through the suspension, support most of the weight of vehicle, and wheel traction or braking force, as well as the lateral force after suspension to frame. In the car used in the steering bridge, the stress condition is more complex, so it should have enough strength. In order to ensure the wheel turns to the correct positioning of angle, make manipulation of light and reduce tire wear, steering bridge should have enough stiffness. In addition, should also try to reduce the weight of the bridge. In short, because of the automobile in the running process of the front axle, the abominable working environment, complicated working condition, the load is alternating load, thus the parts easy to fatigue cracking and even rupture phenomenon. This requires that the structural design must have enough strength, stiffness and resistance to fatigue failure of the ability.The front axle is the main load-bearing parts: the front axle, my company has a tubular and forging type two structural forms, but mainly to forging type mainly. The front ends of each with a fist shape bold part as the kingpin of the site installation. In both sides of the spring support for partial surface, used for the installation of steel plate spring and accessories. Need note here is: U type bolt passes through the front mounting holes need matter beneath the back nut in, often can appear with the front axle sleeve back band interference problem. Why can appear such problem? Design is a problem, because the front dorsal ribs affects front axle load, therefore must have a certain size requirements, and if both before and after the U bolt distance design is too small, not enough gap assembly will appear above problem. Two technical problems, technical problems in two cases. The first is the front dorsal rib symmetry is not good or mounting hole symmetrical degree andeasy to cause the problem; the second is that some host plant in order to avoid the vulnerable, without taking into account the reality of the product and blind to the sleeve outer diameter. Kingpin: is the impact of vehicle performance of main parts. Kingpin has stop groove, pin lock bolt through the stop groove masterPin fixed on the front axle kingpin bore, so that it can't move can not move axially. Knuckle pin machining accuracy is very high, my company is one of the parts of key control. Steering knuckle: steering knuckle is the main steering part of front axle. It uses the main pin and the front axle is hinged by a pair of axle bearing supporting hub combination, to achieve the function of turning. Brake assembly: is the realization of the wheel brake main component, a brake oil and gas brake two forms. Implemented in the vehicle brake command, brake friction plate through the expansion and brake drum machining surface contact friction realization of vehicle brake. Front axle brake option is very critical, if the choice is undeserved, can appear before and after the brake force is not a match, the braking force is not up to the requirements of many problems. Hub combination : by two rolling bearings mounted on the steering knuckle, drive the rotation of the wheels. At the same time with the friction plate to form a friction pair, to realize the brake wheel. Arm: straight rod arm, tie rod arm, respectively, and a straight rod assembly and the tie rod assembly. Formed a steering mechanism and a steering trapezoidal mechanism. The steering mechanism to complete the vehicle steering, steering trapezoid determines the vehicle inside and outside corner is reasonable. The tie rod assembly: is to adjust the beam before the main parts. The rod body is made of seamless steel tube manufacturing, both ends of the spherical hinge joint structure is the joint assembly, by a thread after the installation of the tie rod arm, the rod body is adjustable, so as to adjust the toe. Front axle under the front of the car weight, the car forward thrust from the frame to the wheel, and with the steering device arranged on parts make joint type connection, the implementation of the automobile steering. The front axle is the use of both ends of it through the main pin and the steering knuckle is connected to the steering knuckle, swing to realize vehicle direction.In order to make the running vehicle has good linear driving ability, front axle should meet the following requirements: in order to make the running vehicle has good linear driving ability, front axle should meet the following requirements:1sufficient strength,in order to ensure the reliable bearing wheel and frame ( or monocoque ) between the work force. 2 correct positioning of the wheels, so that the steering wheel movement stability, convenient operation and reduce tire wear. Front wheel positioning includes kingpin inclination, caster, camber and toe-in. 3sufficient rigidity, the force deformation small, ensure the main pin and a steering wheel positioned right angle remains constant. 4knuckle and master pin, steering and front axle between the friction should be as small as possible, to ensure that the steering operation for portability, and has sufficient abrasion resistance. 5 steering wheel shimmy should be as small as possible, in order to ensure the vehicle normal, stable exercise. 6 front axle quality should be as small as possible, in order to reduce unsprung mass, improve vehicle ride comfort.1mini car front axle 1mini car front mini car front suspension generally adopt the independent suspension structure. Front axle load is relatively small, the structure is simple. Mini car front axle usually disconnected movable joint structure, which is composed of a front axle body, strengthen the transverse swing arm, arm etc.. 2 car front axle2 car front axle front axle suspension with Mcpherson car. It bears the driving and steering functions, the suspension is connected with the vehicle body, and the lower end of the wheel bearing housing connected, wheel camber is through the suspension and the bearing shell of the connecting bolt to adjust, auxiliary frame through the elastic part by controlling the arm, ball hinge connected with suspension, improve the driving stability and ride comfort. 3off-road vehicle front axle3off-road vehicle front axle Off-road vehicle steering and driving front axle has two tasks, it is known as the steering driving axle. And it generally drive the movable bridge, with a main driver, differential and the axle shaft. The difference is, due to the need, half shaft is divided into two segments, and by a universal joint, while the main pin are made under paragraph two. The 4truck front axle 4truck front axle truck front axle with I-shaped cross section is mainly used to improve the front bending strength. The upper two plus wide plane, to support the steel plate spring. The front ends each having a fist shape portion, which has a through hole, as a kingpin only. Main pin and left steering knuckle hinge, with a threaded wedge pin crossed with the main pin hole of vertical through holes on the lock pin wedge surface, the main pin is fixed in the axle hole, so that it cannot rotate.In general, common material needed to define the material properties including: elastic modulus, Poisson's ratio, density, specific heat, thermal expansion coefficient. The front axle is mainly composed of two parts, material composition, i.e., front axle and steering knuckle such as zero Department of materials. The front axle is adopted as the material of45 steel, steering knuckle materials using 40Cr.Torsion bar of automobile front independent suspension is the key component, is a slender rod, the induction quenching process is the manufacturing process difficult point, this paper introduces the torsion bar quenching inductor and its process test results, determined using half ring type inductor continuous quenching technology, this method can meet the technical requirements and the quantities of torsion bar production.The forging forging molding, not only greater deformation, but also requires a certain deformation force,Therefore the selection of J53series double disc friction press comparative economics, this series press combined slipping flywheel, combined slipping flywheel can provide highly deformed large forgings with enough to form, and can provide for forgings will required deformation capacity, and not to overload, the series press equipment investment, the cost of the mold and forging cost than die forging hammer and the forging crank press cheap cheap host. At present, the domestic automobile front axle machining process are the following: (1) of two plane milling plate spring seat; the drill two spring seat plane ten holes; the rough milling of two main pin hole of upper and lower end surfaces; the fine mill main pin hole of upper and lower end surfaces; the drilling and reaming main pin hole; the broaching the main pin hole; the main pin hole on the lower end of the countersink reaming pin holes;. In this scheme, the following questionQuestions:1 adopting main pin hole positioning countersink on the lower end, and the end surface of the main pin hole verticality can not be guaranteed, the main pin hole size height can not be guaranteed to the main pin hole; the positioning of the drill pin hole, drill through the cross intersection holes, easy cutting phenomenon, students offset, causing the main pin hole and the locking pin hole center distance can not be guaranteed. (2) of two plane milling plate spring seat; the drill two spring seat plane ten holes; the drilling and reaming pin holes on the rough milling of a main pin hole on upper end; the fine mill main pin hole of upperand lower end surfaces; the drilling and reaming main pin hole. In this scheme, there are the following problems: the process is used to drill the locking pin hole after the drill main pin hole, and the pin - fL: fL size and position size is the key size, kingpin is difficult to ensure the accuracy of the first; fine mill main pin hole of the upper and lower ends after processing the main pin hole, end relative to the main pin hole verticality is difficult to guarantee. (3) of two plane milling plate spring seat; the drill two spring seat plane ten holes; the drilling and reaming pin holes; the rough milling kingpin on upper end; the drilling and reaming main pin hole; the fine mill main pin hole on the lower end surface. In this scheme, there are the following problems : the main pin hole and the pin hole cross intersecting hole size tolerance of0.1mm is not easy to maintain; to adopt the reaming main pin hole, the dimensional tolerances are not easy to be ensured; the final finish milling main pin hole on the lower end surface. The main pin hole and upper and lower end verticality is not easy to guarantee; the main pin hole size can not be guaranteed.Along with our country transportation enterprise rapid development, auto transport carrying capacity and running speed are continually increasing with. So people to the safe operation of the automobile is more and more attention, so the automobile axle design also raised taller requirement. As a result of foreign automobile development starts early, technical inputs, thus technically far ahead of China market, but also there are many insufficient places, still need to improve, technology also needs a breakthrough. Steam car industry as our focus on the development of pillar industries, its prospect is very wide. At present, auto parts production has certain potential, but most enterprises in product research, development and other aspects of the defect, especially lack of less product independent development capacity, can not adapt to the system support, delivery of modules, to participate in international division of labor. Because of this, in the future development, Chinese enterprises should actively absorb the international advanced automotive technology, and constantly improve the self body lines, such as braking systems, steering systems, expand the industry of product variety, improve the integral technology level, increase the strong technological development capability, urges the enterprise faster development, adapt to the trend of globalization of automobile industry.100 years ago, the car was just beginning, the steering is modelled on the carriageand bicycle steering mode, using a joystick or a handle to make the front wheel deflection, thus realizes the steering. Due to the manipulation of effort and unreliable, so often fatal accident. The first horseless pull four wheel vehicle comes out, have a front axle and a front wheel assembly, the assembly being mounted on the crankshaft, front axle center around a point of rotation, using a rod connecting the front axle, focus, through the floor and extends upward, the wheel is fastened on the rod end, in order to manipulate the car. This device in a vehicle speed not exceeding the speed, or very good, but when the vehicle speed is increased, the driver asks to improve steering accuracy, in order to reduce tire wear, prolong the service life of tyre. In 1817, the Germans Lincoln Spang Jay presented similar to the modern automobile, the front wheel with knuckle and beam connection, he developed a kind of automobile front wheel on the main shaft to allow independent rotary structure, which is connected with the steering wheel, steering knuckle and a rotatable pin and front axle, thereby the invention of modern steering trapezoidal mechanism.Since China's reform and opening up, execute in the country the household contract responsibility system reform, make the rural economy is all-time and active. Rural freight traffic and population flow increased dramatically, speeding up the transportation mechanization into rural classicsEconomic development urgent need, it is also the needs of the market that has Chinese distinguishing feature of transport machinery -- emerge as the times require small truck. It has solved the countryside transportation need, fill the villages, townships, towns and urban transportation network is blank, active rural economics, for the surplus rural labor force to find a way out, so that tens of thousands of farmers to be on comparatively well-off road.Small truck manufacturing process is simple, cheap, purchase a car farmers generally in a year or so we can recover the cost. In addition, the highway construction has promoted the rapid development of small truck, the98% villages are on the road, so that the small truck with play.We want to develop a small truck to optimize the design, to make new products, diversification of varieties to meet a variety of needs. In a small truck design, how the complex road conditions to ensure the smooth running of the car quickly, is a serious problem. Then there is the subject of research and design.Automobile front axle driving system important constituent, it is connected with the frame through the suspension, steering wheel mounted at both ends, used to support frame and transmission wheel and frame between a variety of force, and drives the steering knuckle swing to realize vehicle steering. Using the hinge device causes the wheel to deflect a certain angle, so as to realize the steering of a vehicle axle called steering bridge, general vehicle used for steering bridge bridge, the front for steering bridge. Steering bridge not only can make the left and right wheels arranged at the front end to deflect a certain angle to realize the steering, should also be able to bear vertical load and by the road, the brake force is exerted on the longitudinal force and lateral force and the force formed by the moment. Therefore, the steering bridge must have sufficient strength and rigidity. Wheel steering process of internal friction between the pieces should be as small as possible, and to keep the vehicle steering light and the direction stability.Steering axle is generally composed of front axle, steering knuckle, steering knuckle arm, steering knuckle pin and the hub.Front axle general is in the front of the bus, also known as steering axle or drive bridge. The suspension is connected with the frame, used to support the ground and the frame between the vertical load, but also bear the braking force and lateral force and the force moment, and ensure that the steering rotation right movement. In the car used in the steering bridge, stress is more complex, so it should have enough strength. In order to ensure the correct positioning of the steering wheel angle, make the manipulation of light and reduce tire wear, steering bridge should have enough stiffness. In addition, should also try to reduce the weight of the bridge.Front axle under the front of the car weight, the car forward thrust from the frame to the wheel, and the steering device on parts make joint type connection, the implementation of the automobile steering. The cross-country vehicle front axle but also bear and rear axle the same driving task. General cargo vehicle with front engine rear drive arrangement, the front for steering bridge.Automobile front axle design should ensure adequate design strength, to ensure reliable bear acting force between wheel and frame; ensure the adequate rigidity, so that the wheel positioning parameters constant; ensure that the steering wheel have thecorrect localization angle, so that the steering wheel movement stability, convenient operation and reduce the tire friction; steering bridge quality as small as possible, in order to reduce non spring quality, improve the ride comfort of vehicles.译文前桥一般位于汽车的前部，也称转向桥或从动桥。
机械类数控车床外文翻译外文文献英文文献车床.doc
LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances upto 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.2 Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:Electrical discharge machining,Laser cutting,Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tolls and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punchedpaper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.3 TurningThe engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered.The engine lathe has been replaced in today’s production shops by a wide variety of automatic lathes such as automatic of single-point tooling for maximum metal removal, and the use of form tools for finish on a par with the fastest processing equipment on the scene today.Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilled operator. In redesigning an experimental part for production, economical tolerances should be used.Turret Lathes Production machining equipment must be evaluated now, more than ever before, this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating.In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turrets lathe, the designer should strive for a minimum of operations.Automatic Screw Machines Generally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle automatics and automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts, the automatic screw machine has long since exceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic screw machine. Quantities less than on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities.Automatic Tracer Lathes Since surface roughness depends greatly on material turned, tooling , and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, tolerances of 0.05mm are held in continuous production using but one cut . groove width can be held to 0.125mm on some parts. Bores and single-point finishes can be held to 0.0125mm. On high-production runs where maximum output is desirable, a minimum tolerance of 0.125mm is economical on both diameter and length of turn.车床车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。
凸轮设计的基本内容外文文献翻译、中英文翻译、外文翻译
ELEMENTS OF CAM DESIGNHow to plan and produce simple but efficient cams for petrol engines and other mechanismsCams are among the most versatile mechanisms available．A cam is a simple two-member device．The input member is the cam itself，while the output member is called the follower．Through the use of cams，a simple input motion can be modified into almost any conceivable output motion that is desired．Some of the common applications of cams are ——Camshaft and distributor shaft of automotive engine——Production machine tools——Automatic record players——Printing machines——Automatic washing machines——Automatic dishwashersThe contour of high-speed cams (cam speed in excess of 1000 rpm) must be determined mathematically．However，the vast majority of cams operate at low speeds(less than 500 rpm) or medium-speed cams can be determined graphically using a large-scale layout．In general，the greater the cam speed and output load，the greater must be the precision with which the cam contour is machined．Cams in some form or other are essential to the operation of many kinds of mechanical devices. Their best-known application is in the valve-operating gear of internal combustion engines, but they play an equally important part in industrial machinery, from printing presses to reaping machines.In general, a cam can be defined as a projection on the face of a disc or the surface of a cylinder for the purpose of producing intermittent reciprocating motion of a contacting member or follower. Most cams operate by rotary motion, but this is not an essential condition and in special cases the motion may be semi-rotary，oscillatory or swinging. Even straight-line motion of the operating member is possible, though the term cam may not be considered properly applicable in such circumstances.Most text books on mechanics give some information on the design of cams and show examples of cam forms plotted to produce various orders of motion. Where neither the operating speed nor the mechanical duty is very high, there is a good deal of latitude in the nermissible design of the cam and it is only necessary to avoid excessively steep contours or abrupt changes which would result in noise, impact shock, and side pressure on the follower. But, with increase of either speed or load, much more exacting demands are made on the cam, calling for the most careful design and, at very high speed, the effect of inertia on the moving parts is most pronounced, so that the further factors of acceleration and rate of lift have to be taken into account and these are rarely dealt with in any detail in the standard text books.The design of the cam follower is also of great importance and bears a definite relation to the shape of the cam itself. This is because the cam cannot make contact with the follower at a single fixed point. Surface contact is necessary to distribute load and avoid excess wear, thus the cam transmits its motion through various points of location on the follower, depending on the shape ofthe two complementary members. The cams for operating i.c. engine valves present specially difficult problems in design. In the case of racing engines, both the load and speed may be regarded as extreme, because in many engines the rate at which the valves can be effectively controlled is the limiting factor in engine performance. In some respects, cam design of miniature engines is simplified by reason of their lighter working parts (and consequent less inertia) but on the other hand, working friction is usually greater and rotational speeds are generally considerably higher than in full-size practice.In the many designs for small four-stroke engines which I have published, I have sought to simplify valve operation and to provide designs for cams which can be simply and accurately produced with the facilities of the amateur workshop. Numerous engine designs which have been submitted to me by readers have contained errors in the valve gear and particularly in the cams and in view of prevalent misconceptions in the fundamental principles of these items, I am giving some advice on the matter which I trust will help individual designers to obtain the best results from their engines. There have been many engines built with cams of thoroughly bad design but which, in spite of this, have produced results more or less satisfactory to their constructors. It may be said that within certain limits of speed one can get away with murder but in no case can an engine perform efficiently with badly designed cams, or indeed errors in any of its working details. This article is concerned mainly with the design of cams for operating the valves of i.c. engines and, in order to avoid any confusion of terms, Fig. 1 shows the various parts of a cam of this type and explains their functions. The circular, concentric portion of the cam, which has no operative effect, is known as the base circle: the humy of the cam (shown shaded) is known as the lobe, and the flanks on either side rise from the base circle to the nose, which is usually rounded.Lift may be defined as the difference between the radius of the base circle and that of the nose. the anele enclosed between the points where the flanks join the base circle is termed the angular …period, representing the proportion of the full cycle during which the cam operates the valve gear. In Fig. 2, typical examples of cams used in i.c. engines are illustrated. The tangent cam, A, has dead straight flanks-which as the name implies form tangents to the base circle. This type of cam is easy to design and produce, the simplest method of machining being by a circular milling process forming a concentric surface on the base circle and running straight out tangentially where the flanks start and finish. It can also be produced by filing and I have in the past described how to make it with the aid of a roller filing rest in the lathe, in conjunction with indexing gear to locate the flank angles.Tangent cams can only work efficiently in conjunction with a convex curved follower, as this is the only way in which the flank can be brought progressively and smoothly into action. Some time ago an engine was described having tangent cams in conjunction with flat followers. This was not intended for extremely high speed and very likely produced all the power required of it, but it is quite clear that the flat face of the tangent cam. On engaging the flat tappet-over the full length of the flank all at once, must produce an abrupt slapping action which is noisy, inefficient and destructive in the long run. Rollers are often used as followers with tangent cams and are satisfactory in respect of their shape, but the idea of introducing rolling motion at this point is not as good as it seems at first sight, because it merely transfers the sliding friction to a much smaller area--that of the pivot pin. It is possible in some cases, however, to use a ball or roller race for the follower and this, at any rate, has the merit of distributing and equalizing the wearing surface.Tangent cams have been used with a certain degree of success for high-performance-enginesand were at one time popular on racing motorcycle engines, though usually with some slight modification of shape-often “ designed ” by the tuner with the aid of .a Carborundum slip! Their more common application, however, has been on gas and oil engines running at relatively slow speeds, where they work well in contact with rollers attached to the ends of the valve rockers. Cams with convex flanks are extensively used in motor cars and other mass-produced engines. One important advantage in this respect is that they are suited to manufacture in quantity by a copying process from accurately formed master cams. The fact that hat-based tappets can be used also favours quantity production and they can be designed to work fairly silently. The contour of the flank can be plotted so that violent changes in the acceleration of the cam are avoided and, more important still, the tappet will follow the cam on the return motion without any tendency to bounce or float at quite high speeds. In such cases, it may be necessary to introduce compound curves which are extremely difficult to copy on a small scale, but cams made with flanks formmg true circular arcs will give reasonably efficient results, and are very easily produced in any scale: Concave-flanked cams.Comparatively few examples of concave-flanked cams (Fig. 2c) are to be seen nowadays, though they have been used extensively in the past with the idea of obtaining the most rapid opening and closing of the valves. Theoretically, they can be designed to produce consant-acceleration, but in practice they render valve control very difficult at high speed and their fierce angle of attack produces heavy side pressure on the tappet. The concave flank must always have a substantially greater radius than the follower, or a slapping action like that of a tangent cam on a flat follower is produced.The shape of the nose in most types of cams is dictated mainly by the need to decelerate the follower as smoothly as possible. It is one thing to design it in such a way that ideal conditions are obtained, and quite another to ensure in practice that the follower retains close contact with the cam. If the radius of the nose is too small, the follower will bounce and come down heavily on the return flank of the cam and,. if too great, valve opening efficiency will be reduced.Of the three types of cams, A, B and C, which all have identically equal lift and angular period, the lobe of B encloses the smallest area, and on first sight it might appear that it is the least efficient in producing adequate valve opening, or mean lift area, but owing to the use of a flat based tappet, its lift characteristics are not very different from those of a tangent cam with round-based tappet, and not necessarily inferior to those of a concave-flank cam.Unsymmetrical camsIt is not common to make the two flanks of a cam of different contours to produce some particular result which the designer may consider desirable. In some cases, the object is to produce rapid opening and gradual closing, but sometimes the opposite effect is preferred. When all things are considered, however, most attempts to monkey about with cam forms lead to complications which may actually defeat their own object, at least at really high speeds.In many engines, particularly those of motorcycles, the cams operate the valves through levers or rockers which move in an arc instead of in a straight line, as in the orthodox motor car tappet. This may be mechanically efficient, but it modifies the lift characteristic of the cam, as the point at which the latter transmits motion to the follower varies in relation to the radius of the lever arm, (Fig. 3).With the cam rotating in a clockwise direction, the effective length of the lever will be greater in the position.A during valve opening than in positionB during closing, as indicated by dimensions X and Y. This amounts to the same as using an unsymmetrical cam, and in the example shown, would result in slow opening and rapid closing of the valve, or vice versa if either the direction of rotation of the cam, or the relative “hand ” of the lever, is reversed. The shorter the lever, the greater the discrepancy in the rate of movement, Neither the unsymmetrical cam form nor the pivoted lever is condemned as bad design, but I have sought to avoid them in most of the engines I have designed because they are a complicating factor in what is already a very involved problem, and by keeping to fairly simple cams and straight-line tappets, one can be assured that there are not too many snags.The employment of cams with flanks of true circular arc has enabled me to devise means of producing them on the lathe without elaborate attachments and, what is more important still, to produce an entire set of cams for a multi-cylinder engine in correct angular relation to each other by equally simple means. There is no doubt whatever that these methods have enabled many engine constructors (some without previous experience) to tackle successfully a problem which would otherwise have been formidable, to say the least.Many designers have attempted to improve valve efficiency by designing cams which hold the valve at maximum opening for as long a period as possible. This is done by providing dwell or, in other words, making the top of the lobe concentric with the cam axis over a certain angular distance in the centre of its lift. To do this, however, it is necessary to make the flanks excessively steep, thus producing heavy side thrust on the tappet, and making control at high speed more difficult, (Fig. 4A).A little consideration, however, will show that the same result can be achieved, with much less mechanical difficulty, by lifting the valve somewhat higher at an easier rate, as shown at B. This avoids the need for sudden acceleration and deceleration of the tappet and promotes flow efficiency of the valve. The shaded portions of the two cams show the differences in the area of the lobe, showing that nothing is really gained by the dwell. Factors in efficiency High valve lift is a desirable feature, but only if it can be obtained without making extra dificulties in controlling the valve. The maximum port area of a valve is obtained when the lift is equal to one-fourth of the seat diameter, but owing to the baffling effect on the valve head, a higher lift is better for flow efficiency-if it is practicable.Large diameter valves will obviously release and admit gas efficiently but they are more difficult to control and keep cool at high speed than smaller valves. Another point is that the exhaust valve is required to open against a high cylinder pressure, and the larger it is the more the load imposed on the cam, quite apart from the spring load.凸轮设计的基本内容如何为汽油发动机和其他机械设计和生产简单而有效的凸轮凸轮是被应用的最广泛的机械结构之一。
外文文献翻译(中英文)
专业外语与文献阅读英文原文：NOVEL METHOD OF REALIZING THE OPTIMAL TRANSMISSION OF THE CRANK-AND-ROCKER MECHANISM DESIGN Abstract: A novel method of realizing the optimal transmission of the crank-and-rocker mechanism is presented. The optimal combination design is made by finding the related optimal transmission parameters. The diagram of the optimal transmission is drawn. In the diagram, the relation among minimum transmission angle, the coefficient of travel speed variation, the oscillating angle of the rocker and the length of the bars is shown, concisely, conveniently and directly. The method possesses the main characteristic. That it is to achieve the optimal transmission parameters under the transmission angle by directly choosing in the diagram, according to the given requirements. The characteristics of the mechanical transmission can be improved to gain the optimal transmission effect by the method. Especially, the method is simple and convenient in practical use.Keywords：Crank-and-rocker mechanism, Optimal transmission angle, Coefficient of travel speed variationINTRODUCTIONBy conventional method of the crank-and-rocker design, it is very difficult to realize the optimal combination between the various parameters for optimal transmission. The figure-table design method introduced in this paper can help achieve this goal. With given conditions, we can, by only consulting the designing figures and tables, get the relations between every parameter and another of the designed crank-and-rocker mechanism. Thus the optimal transmission can be realized.The concerned designing theory and method, as well as the real cases of its application will be introduced later respectively.1ESTABLISHMENT OF DIAGRAM FOR OPTIMAL TRANSMISSION DESIGNIt is always one of the most important indexes that designers pursue to improve the efficiency and property of the transmission. The crank-and-rocker mechanism is widely used in the mechanical transmission. How to improve work ability and reduce unnecessary power losses is directly related to the coefficient of travel speed variation, the oscillating angle of the rocker and the ratio of the crank and rocker. The reasonable combination of these parameters takes an important effect on the efficiency and property of the mechanism, which mainly indicates in the evaluation of the minimum transmission angle.The aim realizing the optimal transmission of the mechanism is how to find themaximum of the minimum transmission angle. The design parameters are reasonably combined by the method of lessening constraints gradually and optimizing separately. Consequently, the complete constraint field realizing the optimal transmission is established.The following steps are taken in the usual design method. Firstly, the initial values of the length of rocker 3l and the oscillating angle of rocker ϕ are given. Then the value of the coefficient of travel speed variation K is chosen in the permitted range. Meanwhile, the coordinate of the fixed hinge of crank A possibly realized is calculated corresponding to value K .1.1 Length of bars of crank and rocker mechanismAs shown in Fig.1, left arc G C 2 is the permitted field of point A . Thecoordinates of point A are chosen by small step from point 2C to point G .The coordinates of point A are02h y y c A -= (1)22A A y R x -= (2) where 0h , the step, is increased by small increment within range(0,H ). If the smaller the chosen step is, the higher the computational precision will be. R is the radius of the design circle. d is the distance from 2C to G .2c o s )2c o s (22c o s 33ϕθϕϕ⎥⎦⎤⎢⎣⎡--+=l R l d (3) Calculating the length of arc 1AC and 2AC , the length of the bars of themechanism corresponding to point A is obtained [1,2].1.2 Minimum transmission angle min γMinimum transmission angle min γ(see Fig.2) is determined by the equations [3]322142322m i n 2)(c o s l l l l l l --+=γ (4) 322142322m a x 2)(c o s l l l l l l +-+=γ (5) m a x mi n 180γγ-︒=' (6) where 1l ——Length of crank(mm)2l ——Length of connecting bar(mm)3l ——Length of rocker(mm)4l ——Length of machine frame(mm)Firstly, we choose minimum comparing min γ with minγ'. And then we record all values of min γ greater than or equal to ︒40 and choose the maximum of them.Secondly, we find the maximum of min γ corresponding to any oscillating angle ϕ which is chosen by small step in the permitted range (maximum of min γ is different oscillating angle ϕ and the coefficient of travel speed variation K ).Finally, we change the length of rockerl by small step similarly. Thus we3γcorresponding to the different length of bars, may obtain the maximum ofmindifferent oscillating angle ϕand the coefficient of travel speed variation K.Fig.3 is accomplished from Table for the purpose of diagram design.It is worth pointing out that whatever the length of rocker 3l is evaluated, the location that the maximum of min γ arises is only related to the ratio of the length of rocker and the length of machine frame 3l /4l , while independent of 3l .2 DESIGN METHOD2.1 Realizing the optimal transmission design given the coefficient of travelspeed variation and the maximum oscillating angle of the rockerThe design procedure is as follows.(1) According to given K and ϕ, taken account to the formula the extreme included angle θ is found. The corresponding ratio of the length of bars 3l /4l is obtained consulting Fig.3.︒⨯+-=18011K K θ (7) (2) Choose the length of rocker 3l according to the work requirement, the length of the machine frame is obtained from the ratio 3l /4l .(3) Choose the centre of fixed hinge D as the vertex arbitrarily, and plot an isosceles triangle, the side of which is equal to the length of rocker 3l (see Fig.4), andϕ=∠21DC C . Then plot 212C C M C ⊥, draw N C 1, and make angleθ-︒=∠9012N C C . Thus the point of intersection of M C 2 and N C 1 is gained. Finally, draw the circumcircle of triangle 21C PC ∆.(4) Plot an arc with point D as the centre of the circle, 4l as the radius. The arc intersections arc G C 2 at point A . Point A is just the centre of the fixed hinge of the crank.Therefore, from the length of the crank2/)(211AC AC l -= (8)and the length of the connecting bar112l AC l -= (9)we will obtain the crank and rocker mechanism consisted of 1l , 2l , 3l , and 4l .Thus the optimal transmission property is realized under given conditions.2.2 Realizing the optimal transmission design given the length of the rocker (or the length of the machine frame) and the coefficient of travel speed variationWe take the following steps.(1) The appropriate ratio of the bars 3l /4l can be chosen according to given K . Furthermore, we find the length of machine frame 4l (the length of rocker 3l ).(2) The corresponding oscillating angle of the rocker can be obtained consulting Fig.3. And we calculate the extreme included angle θ.Then repeat (3) and (4) in section 2.13 DESIGN EXAMPLEThe known conditions are that the coefficient of travel speed variation1818.1=K and maximum oscillating angle ︒=40ϕ. The crankandrockermechanism realizing the optimal transmission is designed by the diagram solution method presented above.First, with Eq.(7), we can calculate the extreme included angle ︒=15θ. Then, we find 93.0/43=l l consulting Fig.3 according to the values of θ and ϕ.If evaluate 503=l mm, then we will obtain 76.5393.0/504==l mm. Next, draw sketch(omitted).As result, the length of bars is 161=l mm,462=l mm,503=l mm,76.534=l mm.The minimum transmission angle is︒=--+=3698.462)(arccos 322142322min l l l l l l γ The results obtained by computer are 2227.161=l mm, 5093.442=l mm, 0000.503=l mm, 8986.534=l mm.Provided that the figure design is carried under the condition of the Auto CAD circumstances, very precise design results can be achieved.4 CONCLUSIONSA novel approach of diagram solution can realize the optimal transmission of the crank-and-rocker mechanism. The method is simple and convenient in the practical use. In conventional design of mechanism, taking 0.1 mm as the value of effective the precision of the component sizes will be enough.译文：认识曲柄摇臂机构设计的最优传动方法摘要：一种曲柄摇臂机构设计的最优传动的方法被提出。
机械外文翻译文献翻译汽车电动助力转向系统的研究
英文原文The auto electric power steering system researchAlong with automobile electronic technology swift and violent development, the people also day by day enhance to the motor turning handling quality request. The motor turning system hanged, the hydraulic pressure boost from the traditional machinery changes (Hydraulic Power Steering, is called HPS), the electrically controlled hydraulic pressure boost changes (Electronic Hydraulic Power Steering, is called EHPS), develops the electrically operated boost steering system (Electronic Power Steering, is called EPS), finally also will transit to the line controls the steering system (Steer By Wire, will be called SBW).The machinery steering system is refers by pilot's physical strength achievement changes the energy, in which all power transmission all is mechanical, the automobile changes the movement is operates the steering wheel by the pilot, transmits through the diverter and a series of members changes the wheel to realize. The mechanical steering system by changes the control mechanism, the diverter and major part changes the gearing 3 to be composed.Usually may divide into according to the mechanical diverter form: The gear rack type, follows round the world -like, the worm bearing adjuster hoop type, the worm bearing adjuster refers sells the type. Is the gear rack type and follows using the broadest two kinds round the world -like (uses in needing time big steering force).In follows round the world -like in the diverter, the input changes the circle and the output steering arm pivot angle is proportional; In the gear rack type diverter, the input changes the turn and the output rack displacement is proportional. Follows round the world -like the diverter because is the rolling friction form, thus the transmission efficiency is very high, the ease of operation also the service life are long, moreover bearing capacity, therefore widely applies on the truck. The gear rack type diverter with follows round the world -like compares, the most major characteristic is the rigidity is big, the structure compact weight is light, also the cost is low. Because this way passes on easily by the wheel the reacting force to the steering wheel, therefore has to the pavement behavior response keen merit, but simultaneously also easy to have phenomena and so on goon and oscillation, also its load bearing efficiency relative weak, therefore mainly applies on the compact car and。
机械类关于凸轮的中英文翻译
英文原文CamsV arious motions can be produced by the action of a cam against a follower.Mamy timing devices are operated by can action.The purpose of andy cam is to produce a displacement of its follower;a secondary follower is often .used to produce additional displacement in another location.The most popular type is the plate cam.The cylindrical type is used to transmit linear motion to a follower as the cam rotates.Three-dimensional cam are sometimes used;these provide some unusual follower motions,but also make follower design difficult.The camshaft in the automotive engine illustrates a simple but important application of a late cam.The cam assemblies in automatic record players illustrate a somewhat more complex application.Cam profiles are accurately constructed by either praphical or mathematical methods.The transitiom from development drawings to working (shop) drawing can be made in several ways:1.Make a full-scale template.This is desirable from the manufacturing standpoint,but it will not guarantee accurate cam profiles.e radial dimensions.This is fairly accurate,but sometimes produces layout problems in the shop.e coordinate dimensioning.This procedure will ensure accuracy.In selecring one of these methods,one should consider the function of the cam in terms of desired preciseness.Because the cam work outline already determined, therefore the cam structural design mainly was determines the curve outline axial thickness and the cam and the drive shaft connection way. When the work load compares the hour, curve outline axial thickness generally takes for the outline curve biggest radius of vector 1,/10 ～/5; Regarding a stress bigger important situation, must with carry on the design according to the cam contour surface from the contact intensity.When determination cam and drive shaft joint way, should synthesize theconsideration cam the assembling and dismantling, the adjustment and firmly grades the question. Regarding implementing agency more equipment, between its each execution component movement coordination usually determined by the cycle of motion chart, therefore in assembly cam gear time, the cam contour curve initial station (pushes regulation starts) the relative position to have according to the cycle of motion chart to carry on the adjustment, guarantees each execution component to be able according to the pre-set sequence synchronized action. Therefore, requests the cam in the structural design to be able to be opposite to the drive shaft carries on the rotation along the circumference direction, and reliably performs fixedly. The simplest method uses the clamping screw nail fixed cam, or with clamping screw nail pre- fixed, after treats adjusts uses the pin to be fixed again.From structural design: from structure: When design must consider from the guidance and prevented revolves. From movement rule design: Involves many aspects from the movement rule design the questions, besides consideration rigidity impact and flexible impact, but also should maximum speed vmax which has to each kind of movement rule, maximum acceleration amax and its the influence performs the comparison. 1) vmax bigger, then momentum mv is bigger. If from is suddenly prevented, the oversized momentum can cause the enormous impulse, endangers the equipment and the personal safety. Therefore, when is bigger from the quality, in order to reduce the momentum, should choose the vmax value smaller movement rule.2) amax bigger, is bigger. Function in high vice- contact place stress bigger, the organization intensity and the wear resistant request is also higher. Regarding high speed cam, in order to reduce the harm, should choose the amax value smaller movement rule. First states several kind of movements rules vmax, amax, the impact characteristic and the suitable situation following table regarding swings from the cam gear, its movement graph x-coordinate expression cam corner, y-coordinate then separately expresses from, angular speed and angle acceleration. This kind of movement graph has the state of motion and above is same.From structural design: from structure: When design must consider from the guidance and prevented revolves. From movement rule design: The cam gear design basic question 1. cam gears type choice, the definite cam shape, with from maintainsthe high vice- contact from the shape and the movement form and the cam the way 2. from the movement rule design, according to the application situation to from the travelling schedule and the state of motion request, determines from the movement rule. 3. cam gears basic parameter design, determines from the travelling schedule, various movements angle, the cam radius, , the roller radius, the center distance, from the length and so on. 4. cam contours curve design. 5. cam gears bearing capacity computation. 6. cam gears structural design, plan organization assembly drawing and various components shop drawingFromstructural design: from structure: When design must consider from the guidance and prevented revolves. From movement rule design: The cam gear design basic question 1. cam gears type choice, the definite cam shape, with from maintains the high vice- contact from the shape and the movement form and the cam the way 2. from the movement rule design, according to the application situation to fromthe travelling schedule and the movement 1, the cam gear application cam gear is includes the cam the high vice- organization, the cam gear has the structure to be simple, may accurately realize request merit and so on movement rule, thus obtains the widespread application in the industrial production, specially automatic device and in the automatic control device, obtains the widespread application. 2nd, the cam gear classification according to two moves the relative motion characteristic classification between the component (1) the plane cam gear 1) the disk cam; 2) translation cam. (2) space cam gear according to from movement vice- element shape classification (1) apex from; (2) roller from (3) flat base from. Note: Classifies this part of content when the introduction cam gear, should point out each kind of cam gear the good and bad points and its the adaption situation, showed each kind of cam gear the inner link, will build the foundation for the later translation cam and the column cam contour design.3rd, the throwout lever movement rule (1) the cam gear cycle of motion and the basic term terminology push the regulation movement angle: With from pushes the cam corner which the regulation corresponds; Far stops the angle: With from far rests the cam corner which the regulation corresponds; Return trip movement angle: With cam corner which corresponds from the return trip; Nearly stops the angle: With fromnearly rests the cam corner which the regulation corresponds; Cam: Take the cam axle center as the center of a circle, take its outline slightly to diameter r0 as the radius circle; From ravelling schedule: In pushes in the regulation or the return trip from the biggest displacement, indicated with h;: The cam center of rotation with from guides way the bias distance, indicated with e.Types of CamsPlate cams are simple to fabricate.The follower can be moved in various patterns with various rise /fall ratios.Motion should be controlled to avoid abrupt changes in force transmitted from the cam to the follower.One should carefully determine horizontal force components,since these present problems designing the follower assembly guide.Critical reactions occur at points A and B.These reaction values must be computed.The relative vertical position of point A with respect to B needs to be raised if the reaction value at Bis excessive.The position of B should be as close to cam as possible to minimize flexure in the roller-follower support.This type produces reciprocating motion in the follower.Again,dorces need to be determined and dimensions chosen so as to avoid excessive component sizes.A tapered roller follower is frequently employed ;the groove in the periphery of the cam should be shaped to accommodate the follower.This type of cam is expensive to produce.The cylindrical cam has two outstanding features.One is the fact that the cam is positive actiong.N outside forces (such as gravity or spring action ) are needed to hold the follower against the working surface of the cam.The second feature is the fact that the follower can move through a complete cycle in the course of several revolutions of the cam.For example,it is possible to design the cam so the follower could move from a starting position at the left end to the extreme right position in three revolutions( or more),then the starting position in two revolutions.Other variations are possible.A translation cam is illustrated.In the figure shown the cam reciprocates horizontally and the follower moves up and down.A pivoted follower can be used with this type .The translation cam can be made positive by providing a guided plate with an inclined slot for the cam;the slot cam then engage a pin or roller on a guided vertical reciprocated follower.With the latter type ,however,a complete force analysisis a critical phase of the design.In this type,the cam rotates and the follower (ususlly a roller or pin) is guided by a groove cut into the end face of a cylindrical section .Rotation of the cam provides translation of the follower.This type is also positive acting.Production costs for this type of cam are much higher than for a simple plate cam.A constant –diameter cam is illustrated .This is merely a circular plate with the camshaft hole eccentrically located.The amount of eccentricity determines the amount of follower displacement.As the cam rotates,the follower reciprocates.This arrangement is sometimes known as a Scotch yoke mechanism.Follower action is positive ;harmonic motion is produced by this type of arrangement.Types of FollowersIn neneral,the follower is considered to be the part that comes in contact with the cam profile .However,when a seconday follower is used, the motion of the secondary follower is dictated by that of the primary follower.For example ,a roller follower can be reciprocated by acting against the edge of a pivoted follower.The simplest type of follower is the reciprocationg type that merely moves up and down (or in and out ) with the rotation of the cam;the centerline can be either collinear with the cam centerline or offset from it .Contact with the cam can be via a point,a knife edge,a suface ,or a roller.A flat-afced reciprocating follower is shown If a point or surface is employed for contact the high normal force can result in abrasion and excessive wear.If the load being transmitted from the cam to the follower is small,the problem is not serious.For example ,the operation of a small snap-action switch does not produce cam surface wear.Miniature snap-action electrical switches have actuators with various configurations;some of these are in the form of rounded points or thin meta sections.Miniature three-way valves in air circuits have similar actuators.If cams are used to operate mechanical components directly,a roller is much more effective.Cam rollers are commercially available in roller sizes ranging from1/2 in .to 6 in Basic dynamic capacities range from 620 to 60000 ,based on 33.33 rpm and 500hr of minimum life .Correction factors must be used for any other speed or life values.It should be noted that the cam can be lubricated through and oil hole in the end of theshank.Rolling contact with the cam surface minimizes wear problems.Several mounting arrangements are possible with this type of followr .shows the roller follower mounted on a pivoted arm .A pivoted flat-faced follower is shown .As with any flat-faced follower,friction between the follower face and the cam profile must be controlled.Proper lubrication can reduce the effects of friction.汉语翻译:凸轮通过凸轮和从动件的作用，可得到不同的运动。
凸轮设计外文翻译参考文献
外文文献翻译(含：英文原文及中文译文)英文原文Failure Analysis, Dimensional Determination And Analysis , ApplicationsOf CamsINTRODUCTIONIt is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed. Sometimes a failure can be serious, such as when a tire blows out on an automobile traveling at high speed. On the other hand, a failure may be no more than a nuisance. An example is the loosening of the radiator hose in an automobile cooling system. The consequence of this latter failure is usually the loss of some radiator coolant, a condition that is readily detected and corrected. The type of load a part absorbs is just as significant as the magnitude . Generally speaking , dynamic loads with direction reversals cause greater difficulty than static loads, and therefore, fatigue strength must be considered. Another concern is whether the material is ductile or brittle. For example, brittle materials are considered to be unacceptable where fatigue is involved.Many people mistakingly interpret the word failure to mean the actual breakage of a part . However , a design engineer must consider abroader understanding of what appreciable deformation occurs. A ductile material, however will deform a large amount prior to rupture. Excessive deformation, without fracture, may cause a machine to fail because the deformed part interferes with a moving second part . Therefore , a part fails(even if it has not physically broken)whenever it no longer fulfills its required function . Sometimes failure may be due to abnormal friction or vibration between two mating parts. Failure also may be due to a phenomenon called creep, which is the plastic flow of a material under load at elevated temperatures. In addition, the actual shape of a part may be responsible for failure . For example , stress concentrations due to sudden changes in contour must be taken into account . Evaluation of stress considerations is especially important when there are dynamic loads with direction reversals and the material is not very ductile.In general, the design engineer must consider all possible modes of failure, which include the following.—— Stress—— Deformation—— Wear—— Corrosion—— Vibration—— Environmental damage—— Loosening of fastening devicesThe part sizes and shapes selected also must take into account many dimensional factors that produce external load effects , such as geometric discontinuities , residual stresses due to forming of desired contours, and the application of interference fit joints.Cams are among the most versatile mechanisms available . A cam is a simple two-member device. The input member is the cam itself, while the output member is called the follower. Through the use of cams, a simple input motion can be modified into almost any conceivable output motion that is desired. Some of the common applications of cams are : —— Camshaft and distributor shaft of automotive engine—— Production machine tools—— Automatic record players—— Printing machines—— Automatic washing machines—— Automatic dishwashersThe contour of high-speed cams (cam speed in excess of 1000 rpm) must be determined mathematically. However , the vast majority of cams operate at low speeds(less than 500 rpm) or medium-speed cams can be determined graphically using a large-scale layout . In general, the greater the cam speed and output load, the greater must be the precision with which the cam contour is machined.DESIGN PROPERTIES OF MATERIALSThe following design properties of materials are defined as they relate to the tensile test .Static Strength. The strength of a part is the maximum stress that the part can sustain without losing its ability to perform its required function. Thus the static strength may be considered to be approximately equal to the proportional limit , since no plastic deformation takes place and no damage theoretically is done to the material.Stiffness . Stiffness is the deformation-resisting property of a material. The slope of the modulus line and , hence , the modulus of elasticity are measures of the stiffness of a material .Resilience . R esilience is the property of a material that permits it to absorb energy without permanent deformation. The amount of energy absorbed is represented by the area underneath the stress-strain diagram within the elastic region.Toughness . Resilience and toughness are similar properties. However , toughness is the ability to absorb energy without rupture. Thus toughness is represented by the total area underneath the stress-strain diagram , as depicted in Figure 2. 8b . Obviously , the toughness and resilience of brittle materials are very low and are approximately equal. Brittleness . A brittle material is one that ruptures before any appreciable plastic deformation takes place. Brittle materials are generally considered undesirable for machine components because they are unable to yieldlocally at locations of high stress because of geometric stress raisers such as shoulders, holes , notches , or keyways.Ductility . A ductility material exhibits a large amount of plastic deformation prior to rupture. Ductility is measured by the percent of area and percent elongation of a part loaded to rupture. A 5%elongation at rupture is considered to be the dividing line between ductile and brittle materials.Malleability . Malleability is essentially a measure of the compressive ductility of a material and, as such, is an important characteristic of metals that are to be rolled into sheets .Hardness . The hardness of a material is its ability to resist indentation or scratching . Generally speaking, the harder a material, the more brittle it is and, hence , the less resilient. Also , the ultimate strength of a material is roughly proportional to its hardness .Machinability . M achinability is a measure of the relative ease with which a material can be machined. In general, the harder the material, the more difficult it is to machine.Figure 2.8COMPRESSION AND SHEAR STATIC STRENGTHIn addition to the tensile tests, there are other types of static load testing that provide valuable information.Compression Testing. Most ductile materials have approximately thesame properties in compression as in tension. The ultimate strength, however , can not be evaluated for compression . As a ductile specimen flows plastically in compression, the material bulges out , but there is no physical rupture as is the case in tension. Therefore , a ductile material fails in compression as a result of deformation, not stress.Shear Testing. Shafts, bolts , rivets , and welds are located in such a way that shear stresses are produced. A plot of the tensile test. The ultimate shearing strength is defined as the stress at which failure occurs. The ultimate strength in shear, however , does not equal the ultimate strength in tension . For example , in the case of steel , the ultimate shear strength is approximately 75% of the ultimate strength in tension. This difference must be taken into account when shear stresses are encountered in machine components.DYNAMIC LOADSAn applied force that does not vary in any manner is called a static or steady load. It is also common practice to consider applied forces that seldom vary to be static loads. The force that is gradually applied during a tensile test is therefore a static load.On the other hand, forces that vary frequently in magnitude and direction are called dynamic loads. Dynamic loads can be subdivided to the following three categories. Varying Load. With varying loads , the magnitude changes , but the direction does not . For example, the loadmay produce high and low tensile stresses but no compressive stresses .Reversing Load. In this case, both the magnitude and direction change. These load reversals produce alternately varying tensile and compressive stresses that are commonly referred to as stress reversals.Shock Load. This type of load is due to impact. One example is an elevator dropping on a nest of springs at the bottom of a chute. The resulting maximum spring force can be many times greater than the weight of the elevator, The same type of shock load occurs in automobile springs when a tire hits a bump or hole in the road.FATIGUE FAILURE-THE ENDURANCE LIMIT DIAGRAMThe test specimen in Figure 2.10a . , after a given number of stress reversals will experience a crack at the outer surface where the stress is greatest. The initial crack starts where the stress exceeds the strength of the grain on which it acts. This is usually where there is a small surface defect, such as a material flaw or a tiny scratch. As the number of cycles increases, the initial crack begins to propagate into a continuous series of cracks all around the periphery of the shaft . The conception of the initial crack is itself a stress concentration that accelerates the crack propagation phenomenon . Once the entire periphery becomes cracked , the cracks start to move toward the center of the shaft . Finally , when the remaining solid inner area becomes small enough , the stress exceeds the ultimate strength and the shaft suddenly breaks. Inspection of the break reveals avery interesting pattern, as shown in Figure 2.13. The outer annular area is relatively smooth because mating cracked surfaces had rubbed against each other . However , the center portion is rough, indicating a sudden rupture similar to that experienced with the fracture of brittle materials.This brings out an interesting fact. When actual machine parts fail as a result of static loads , they normally deform appreciably because of the ductility of the material.Thus many static failures can be avoided by making frequent visual observations and replacing all deformed parts. However , fatigue failures give to warning. Fatigue fail mated that over 90% of broken automobile parts have failed through fatigue.The fatigue strength of a material is its ability to resist the propagation of cracks under stress reversals. Endurance limit is a parameter used to measure the fatigue strength of a material . By definition, the endurance limit is the stress value below which an infinite number of cycles will not cause failure.Let us return our attention to the fatigue testing machine in Figure 2.9. The test is run as follows:A small weight is inserted and the motor is turned on. At failure of the test specimen , the counter registers the number of cycles N, and the corresponding maximum bending stress is calculated from Equation 2.5. The broken specimen is then replaced by an identical one, and an additional weight is inserted to increase the load. Anew value of stress is calculated, and the procedure is repeated until failure requires only one complete cycle . A plot is then made of stress versus number of cycles to failure. Figure 2.14a shows the plot, which is called the endurance limit or S-N curve. Since it would take forever to achieve an infinite number of cycles, 1 million cycles is used as a reference. Hence the endurance limit can be found from Figure 2.14a by noting that it is the stress level below which the material can sustain 1 million cycles without failure.The relationship depicted in Figure 2.14 is typical for steel, because the curve becomes horizontal as N approaches a very large number. Thus the endurance limit equals the stress level where the curve approaches a horizontal tangent. Owing to the large number of cycles involved , N is usually plotted on a logarithmic scale, as shown in Figure 2.14b. When this is done , the endurance limit value can be readily detected by the horizontal straight line . For steel , the endurance limit equals approximately 50% of the ultimate strength . However , if the surface finish is not of polished equality , the value of the endurance limit will be lower. For example, for steel parts with a machined surface finish of 63 microinches ( μin. ) , the percentage drops to about 40%. For rough surfaces (300μin. or greater), the percentage may be as low as 25%.The most common type of fatigue is that due to bending. The next most frequent is torsion failure, whereas fatigue due to axial loads occursvery seldom. Spring materials are usually tested by applying variable shear stresses that alternate from zero to a maximum value , simulating the actual stress patterns.In the case of some nonferrous metals , the fatigue curve does not level off as the number of cycles becomes very large . This continuing toward zero stress means that a large number of stress reversals will cause failure regardless of how small the value of stress is. Such a material is said to have no endurance limit. For most nonferrous metals having an endurance limit, the value is about 25% of the ultimate strength.EFFECTS OF TEMPERATURE ON YIELD STRENGTH AND MODULUS OF ELASTICITYGenerally speaking , when stating that a material possesses specified values of properties such as modulus of elasticity and yield strength, it is implied that these values exist at room temperature. At low or elevated temperatures, the properties of materials may be drastically different. For example, many metals are more brittle at low temperatures. In addition , the modulus of elasticity and yield strength deteriorate as the temperature increases . Figure 2.23 shows that the yield strength for mild steel is reduced by about 70% in going from room temperature to 1000o F .Figure 2.24 shows the reduction in the modulus of elasticity E for mild steel as the temperature increases. As can be seen from the graph, a 30% reduction in modulus of elasticity occurs in going from roomtemperature to 1000o F . In this figure, we also can see that a part loaded below the proportional limit at room temperature can be permanently deformed under the same load at elevated temperatures.CREEP: A PLASTIC PHENOMENONTemperature effects bring us to a phenomenon called creep, which is the increasing plastic deformation of a part under constant load as a function of time. Creep also occurs at room temperature, but the process is so slow that it rarely becomes significant during the expected life of the temperature is raised to 300o C or more , the increasing plastic deformation can become significant within a relatively short period of time . The creep strength of a material is its ability to resist creep, and creep strength data can be obtained by conducting long-time creep tests simulating actual part operating conditions. During the test , the plastic strain is monitored for given material at specified temperatures.Since creep is a plastic deformation phenomenon , the dimensions of a part experiencing creep are permanently altered. Thus , if a part operates with tight clearances, the design engineer must accurately predict the amount of creep that will occur during the life of the machine. Otherwise , problems such binding or interference can occur. Creep also can be a problem in the case where bolts are used to clamp tow parts together at elevated temperatures. The bolts, under tension, will creep as a function of time . Since the deformation is plastic, loss of clamping forcewill result in an undesirable loosening of the bolted joint. The extent of this particular phenomenon, called relaxation, can be determined by running appropriate creep strength tests.SUMMARYThe machine designer must understand the purpose of the static tensile strength test . This test determines a number of mechanical properties of metals that are used in design equations. Such terms as modulus of elasticity, proportional limit, yield strength, ultimate strength, resilience , and ductility define properties that can be determined from the tensile test.Dynamic loads are those which vary in magnitude and direction and may require an investigation of the machine part’s resistance to failure. Stress reversals may require that the allowable design stress be based on the endurance limit of the material rather than on the yield strength or ultimate strength.Stress concentration occurs at locations where a machine part changes size, such as a hole in a flat plate or a sudden change in width of a flat plate or a groove or fillet on a circular shaft. Note that for the case of a hole in a flat or bar, the value of the maximum stress becomes much larger in relation to the average stress as the size of the hole decreases . Methods of reducing the effect of stress concentration usually involve making the shape change more gradual.Machine parts are designed to operate at some allowable stress below the yield strength or ultimate strength. This approach is used to take care of such unknown factors as material property variations and residual stresses produced during manufacture and the fact that the equations used may be approximate rather that exact . The factor of safety is applied to the yield strength or the ultimate strength to determine the allowable stress. Temperature can affect the mechanical properties of metals. Increases in temperature may cause a metal to expand and creep and may reduce its yield strength and its modulus of elasticity . If most metals are not allowed to expand or contract with a change in temperature , then stresses are set up that may be added to the stresses from the load. This phenomenon is useful in assembling parts by means of interference fits. A hub or ring has an inside diameter slightly smaller than the mating shaft or post. The hub is then heated so that it expands enough to slip over the shaft. When it cools, it exerts a pressure on the shaft resulting in a strong frictional force that prevents loosening.中文译文失效分析，尺寸确定与分析，凸轮的应用引言设计工程师知道如何以及为什么部件出现故障是绝对必要的，这样可以设计出需要最少维护的可靠机器。
汽车润滑油英文文献
汽车润滑油英文文献Lubrication system introduction1 the role of lubrication system, and lubricationIn the lubrication system is the main function of the engine lubrication friction surface of relative motion of the parts.Many engine working, the relative movement of the parts, such as: crankshaft, CAM sleeve and bearing, the piston and cylinder wall, valve and pipe, pretty or rocker arm and CAM, etc. Whatever parts surface machining accuracy high, must be in two parts is maintained between the friction surface layer of the lubricating oil film, in order to reduce the wear and tear of parts and power consumption.Two parts of the friction surface direct contact friction, called dry friction. In the friction resistance is very big, not only cause the increase of engine power consumption, also can make the parts wear faster. Shorten the service life. More seriously, when due to the friction heat is very big, can make the parts temperature rise rapidly in a short time, destroy the fit clearance. The moving parts of movement is blocked, a further rise in temperature will cause the parts surface melt and adhesion, causes serious engine mechanical accident even scrapped.Oil lubrication system of the basic tasks is to continuously supply various parts of the friction surface, reduce the friction and wear of the parts. At the same time, the lubricating oil flowing through the parts surface, take away parts of friction heat on the surface of the z to remove scrap metal layer on the surface of the parts. And the air into the impurities such as dust and burning charcoal to pull in the parts surface oil film. Also can protect the parts from water. Direct effect of air and gas. Protectthe parts from chemical and oxygen corrosion; The viscosity of the lubricating oil has certain. Can also fill the lack of the clearance between the piston ring 2 q and wall, reduce the gas leakage and sealing effectTherefore lubrication system in addition to the lubrication, also has a cooling, cleaning, protection and sealing, and so on.All parts of the engine lubrication depends on the strength in parts of the environment, the relative speed and bear the size of the mechanical load and thermal load. According to different intensity of lubrication, the lubrication ways under the engine lubrication system used; L, 2, splash lubrication 3 pressure lubrication, lubrication 4, pressure lubrication on a regular basis Pressure lubrication is the use of oil pump, will have certain pressure of lubricating oil asked continuously sent to parts of the friction surface, formation has certain thickness and can withstand the mechanical load of oil film, as far as possible to separate two friction parts completely, realize reliable lubrication. Engine on a relatively high speed, high load mechanical parts, use this way of lubrication, such as the crankshaft between journal and bearing, CAM wheel between journal and bearing with rocker arm, rocker arm shaft etc. Use pressure lubrication; Must be on the cylinder block or cylinder head is equipped with special oil pump lubricant to theseparts.Splash lubrication is to use some movement when engine working parts (mainly the crankshaft and camshaft) or from the connecting rod rotates splash up big head set oil hole spewing oil droplets and oil mist lubrication was carried out on the friction surface of a way. Splash lubrication is suitable for: the exposed surface of the parts, such as cylinder wall, CAM, etc.; Relativespeed lower parts, such as piston pin, etc.; Mechanical load lighter parts, such as a column. Cylinder wall USES the splash lubrication, can also prevent due to the large amount of lube oil pressure is too high, oil into the combustion chamber, lead to the deterioration of engine working conditions.Lubrication on a regular basis for some of the less important, scattered parts, by filling the manner of the grease lubrication on a regular basis, such as engine water pump bearings, alternators, starters and column ECU (or distributor such as assembly of lubrication, namely, in this way.2 about the composition of the lubrication system(l) the oil pan. Storage of lubricating oil. On most engines, the oil finished bottom also have the effect of lubricating oil cooling.(2) the oil pump. T ake out a certain amount of lubricating oil from the oil sump pressure after continuously sent to the parts surface lubrication, maintenance cycle of lubricating oil in the lubrication system. Most oil pump installed in the crankcase, others will be installed in oil pump crankcase outside, oil pump adopts gear drive way, through the camshaft, crankshaft, or timing gear to drive.(3) the oil filter. Used to filter out the impurities, abrasive dust and sludge in oil and water and sundry, make to the lubrication parts are clean of oil. Due to the filtering ability is proportional to the flow resistance, lubrication system of filter press filter ability into the oil filter, oil filter and oil filter three, located in different parts of the lubrication system.Oil filter to filter type, filter out the oil in the particle size for a large amount of impurities, the flow resistance is small, series installed on the oil pump inlet before. Oil strainer is used to filterout the oil in the grain size larger impurities and its flow resistance is small, series installed between export oil pump and main oil way. Oil filter can filter out small impurities in the oil, but the flow resistance is bigger, so the more and the main oil passage in parallel, only a small amount of oil through a fine filter to filter.(4) the main oil passage. Lubrication system is an important part of the directly on the cylinder block and cylinder head casting, used to sending oil to the lubrication parts. (5) valve class. Pressure limiting valve is used to limit the lubricating oil pressure of lubricating oil pump output. Bypass valve in the strainer clogging when open, the output oil pump of the lubricating oil can be directly into the main oil passage. Oil filter oil inlet pressure limiting valve is used to restrict access to the fine filter of oil,to prevent too much due to the volume of oil into the fine filter, resulted in the main oil way to reduce pressure lubrication.Lubrication system is also equipped with engine oil pressure gauge, oil temperature table, etc. Some heat load larger engine, such as off-road vehicle engine and diesel engine, no oil radiator, radiator cooling oil.3 oil lubrication systemLiberation of CA6102 engine lubricating oilOil pump is located in the crankcase oil pump in the first line of the main bearing seat bottom, inlet through the tubing is connected to a fixed set filter Oil outlet via a tubing of the bifurcation and fixed respectively in the coarse filter and fine filter on either side of the cylinder body is same. Main oil passage along the longitudinal arrangement, is in the left side of the cylinder block. Seven lateral vittae main oil way communicatewith seven main bearing hole. There are four horizontal oil way is communicate with camshaft bearing hole. At the side of the cylinder body close to the CAM shaft, vertical oil also has the tao with the rocker arm bearing vertical oil communication.Mounted on the oil pump drive shaft of oil pump drive gear driven directly by the crankshaft timing gear. Engine working, the oil pump to pass through the set the lubrication oil in the oil sump filter before, after the oil pump pressure, the oil pump oil outlet. Most of lubricating oil from the oil pump oil outlet after the output, the flowline sent to the primary filter, filter out the larger particles of impurities, into the main oil passage. Output from the oil pump oil outlet of the lubricating oil, there is a small part (accounts for about 10% of the total output of oil - 15%) via a tubing into the fine filter. Fine filter adopts centrifugal filtration method, filtering ability is strong, can filter out small impurities in lubricating oil. The filtered oil flow directly back to the oil sump.Lubricating oil into the main oil passage, the horizontal oil way respectively in each main bearing of crankshaft and camshaft bearing, crankshaft spindle shaft neck collar and camshaft for pressure lubrication, the lubrication oil in the crankshaft main bearing of crankshaft main bearing and connecting rod bearing internal oil duct into the connecting rod bearing, lubrication connecting rod journal. Vertical shaft neck of the camshaft oil, lubricating oil to the rocker arm bearing in the horizontal oil way way hand in person within the rocker arm shaft vertical oil, lubrication radial and axial.The connecting rod big head spray hole and main bearing and connecting rod bearing oil road alignment, oil from the oil hole, on CAM, lifter, piston and cylinder wall to splash lubrication, etc. Splash into the piston lubricating oil through the connectingrod small oils hole on, lubrication of piston pin. From among the rocker shaft hole upper spray lubricating oil from the oil hole is carried out on the rocker arm and valve rod, push rod and valve lubrication. Flow in the push rod to a column within the lubricating oil lubrication under the push rod end, and then out the lifter lower oil hole, and directly to the lubricating oil splash lubrication CAM surface.After fine filter to filter the oil is not lubrication, oil flow directly back to the bottom end. Into the fine filter to prevent too much oil and influence of the main oil passage for the oil and oil pressure, and the fine filter set limited pressure valve inlet, when the oil pump output pressure and the oil amount is lower than a certain value, the pressure limiting valve does not open, to ensure that in this case all lubricating oil into the oil rate.Oil pump output pressure is too high, can also be harmful. Not only easy to cause oil leakage. Also can increase the power loss of engine. Therefore, in the oil pump oil outlet valve limited. When oil pump output pressure is too high, the valve is opened, the pressure oil discharged into the oil pan, the lower the output pressure.At the end of the main oil passage, there is main oil pressure regulating valve, used to adjust and limits the main oil passage for MTP. Oil strainer lid with by-pass valve, once the strainer silt impurities, uneven oil occurs, the valve is open, and lubricating oil without oil strainer directly into a rate that guarantees to various parts of the lubrication. The main oil path, engine oil pressure gauge also has sensors and oil pressure alarm switch, respectively through the conductor and the driving indoor engine oil pressure gauge and oil pressure warning lamp is connected, can timely show the main oil passage for oil pressure,or when the engine oil pressure is too low, the alarm to the driver.Timing gear is located in the crankcase, adopt the way of spray lubrication lubrication润滑系简介1润滑系的作用和润滑方式润滑系的主要作用就是对发动机中相对运动的零件的摩擦表面进行润滑。
毕业设计论文外文文献翻译汽车专业发动机概述中英文对照[管理资料]
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General comments of automobile engineEngine is the source of far, automotive engines are all powered by heat except for a few of automotives drived by automotive engines are called internal combustion engines because fuel burns inside the engine .The engine converts the burning fuel’s thermal energy to mechanical energy.By Cooling Systems Liquid-cooled engines and air-cooled engines are being used .Liquid-cooled engines are the most common in the diesel industry .By Fuel System Gasoline diesel and propane fuel systems are currently used in a wide variety of engines .By Ignition Method Gas engines use the spark (electrical)ignition diesel engines use the heat fro BDC to TDC ;it varies with cylinder bore size ,length of piston stroke ,and numb system injection .The calory of diesel engine come from the fuel emblazed by the compressed diesel engine’compression ration is much bigger than the gas sufficient calory is from the fuel burned by the pressed air.By valve Arrangement Four types of valve arrangements have been used in gasoline and diesel engines .Of the four types (L, T ,F ,and I heads ),the I head is commonly used on diesel engines .By Cylinder Arrangement Engine block configuration or cylinder arrangement depends on cylinder block design .Cylinders may be arranged in a straight line one behind the other .The most common in-line designs are the four-and six-cylinder engines .The V type of cylinder arrangement uses two banks of cylinders arranged in a 60°to 90°V design .The most common examples are those with two banks of three to eight cylinders each .The opposed engine uses two banks of cylinders opposite each other with the crankshaft in between .Engine’classificationAccording to the differences of the piston’movement, the piston intenal combusition engine will be classified reciprocating intenal combusition engine and rotary piston intenal combusition we will introduce working principle diagram of reciprocating internal combustion engine.Except for the wankel rotary ,engine ,all production automotive engines are the reciprocating ,or piston ,design . Reciprocating means “up and down “ or “back and forth“ .It is this up-and-down action of a piston in a cylinder that gives the reciprocating engine its name .Almost all engines of this type are built upon a cylinder block ,or engine block .The block is an iron or aluminum casting that contains the engine cylinders .The top of the block is covered with the cylinder head ,which forms the combustion chambers .The bottom of the block is covered with an oil pan ,or oil sump .A major exception to this type of engine on struction is the air-cooled V olkwagen engine .It is representative of the horizontally opposed air-cooled engines used by Porsche ,Chevrolet (Corvair ) ,and some other automobile manufacturers in years past .Power is produced by the inline motion of a piston in a cylinder .However ,this linear motion must be changed to rotating motion to turn the wheels of a car or truck .The piston is attached to the top of a connecting rod by a pin ,,called a piston pin or connecting rod transmits the up-and –down motion of the piston to the crankshaft ,which changes it to rotating motion .The connecting rod is mounted on the crankshaft with large bearings called rod bearings .Similar bearings , called main bearings ,are used to mount the crankshaft in the block.The crankshaft changes the reciprocating motion of the pistons to rotating motion .The combustible mixture of gasoline and air enters the cylinders through valves .Automotive engines use poppet valves .The valves can be in the cylinder head or in the block .The opening and closing of the valves is controlled by a camshaft .Lobes on the camshaft push the valves open as the camshaft rotates .A spring closes each valve when the lobe is not holding it open .The most common arrangements of engine cylinders and valves are discussed later .The basic single-cylinder engine consists of a cylinder (engine block ),a movable piston inside this cylinder ,a connecting rod attached at the top end to the piston and at the bottom to the offset portion of a crankshaft ,a camshaft to operate the two valves (intake and exhaust ), and a cylinder head .A flywheel is attached to one end of the crankshaft .The other end of the crankshaft has a gear to drive the camshaft gear .The camshaft gear is twice as large as the crankshaft gear .This drives the camshaft at half the speed of the crankshaft on four-stroke-cycle engines ,the crankshaft and camshaft run at the same speed .Energy ConversionThe internal combustion diesel engine is a device used to convert the chemical energy of the fuel into heat energy and then convert this heat energy into usable mechanical energy .This is achieved by combining the appropriate amounts of air andfuel and burning them in an enclosed cylinder at a controlled rate .A movable piston in the cylinder is forced down by the expanding gases of combustion .The movable piston in cylinder is connected to the top of a connecting rod .The bottom of the connected rod is attached to the offset portion is transferred to the crankshaft ,As the piston is forced down ,this offset portion of a crankshaft ,to rotate .The reciprocating (back and forth or up and down )movement of the piston is converted to rotary (turning )motion of the crankshaft ,which supplies the power to drive the vehicle .In general an average air-fuel ratio for good combustion is about 15parts of air to 1 part of fuel by weight .However ,the diesel engine always takes in a full charge of air (since there is no throttle plate in most systems ) ,but only a small part of this air is used at low or idle engine speeds .Air consists of about 20 percent oxygen while the remaining 80 percent is mostly nitrogen .This means that ,for every gallon of fuel burned ,the oxygen in 9,000 to 10,000gallons of air is required .Four-Stroke CycleGasoline by itself will not burn ,it must be mixed with oxygen (air ) .This burning is called combustion and is a way of releasing the energy stored in the air-fuel mixture .To do any useful work in an engine ,the air-fuel mixture must be compressed and burned in a sealed chamber .Here the combustion energy can work on the movable piston to produce mechanical energy .The combustion chamber must be sealed as tightly as possible for efficient engine operation .Any leakage from the combustion chamber allows part of the combustion energy to dissipate without adding to the mechanical energy developed by the piston movement .The 4-stroke engine is also called the Otto cycle engine ,in honor of the German engineer ,Dr. Nikolaus Otto ,who first applied the principle in 1876 .In the 4-stroke engine ,four strokes of the piston in the cylinder are required to complete one full operating cycle :two strokes up and two strokes down .Each stroke is named after the action it performs-intake ,compression ,power ,and exhaust :1、Intake Stroke As the piston moves down ,the vaporized ,mixture of fuel ;and air enters the cylinder past the open intake valve .2、Compression Stroke The piston returns up ,the intake valve closes ,the mixture is compressed within the combustion chamber ,and ignited by a spark .3、Power Stroke The expanding gases of combustion force the piston down in the cylinder .The exhaust valve opens near the bottom of the stroke .4、Exhaust Stroke The piston moves back up with the exhaust valve open ,and the burned gases are pushed out to prepare for the next intake stroke .The intake valve usually opens just before the top of the exhaust stroke .This 4-stroke cycle is continuously repeated in every cylinder as long as the engine remains running .Two-Stroke-CycleThe two-stroke-cycle diesel engine completes all four events:intake,compression, power ,and exhaust. in one revolution of the crankshaft or two strokes of the piston .A series of ports or openings is arranged around the cylinder in such a position that the ports are open when the piston is at the bottom of its stroke .A blower forces air into the cylinder through the open ports .expelling all remaining exhaust gases past the open exhaust valves and filling the cylinder with air .This is called scavenging .As the piston moves up ,the exhaust valves close and the piston covers the ports .The air trapped above the piston is compressed ton covers the ports .The air trapped above the piston is compressed since the exhaust valve is closed .Just before the piston reaches top dead center ,the required amount of fuel is injected into the cylinder .The heat generated by compressing the air ignites the fuel almost immediately .Combustion continues until the fuel injected has been burned .The pressure resulting from combustion forces the piston downward on the power stroke .When the piston is approximately falfway down ,the exhaust valves are opened ,allowing the exhaust gases to escape .Further downward movement uncovers the inlet ports ,causing fresh air to enter the cylinder and expel the exhaust gases .The entire procedure is then repeated ,as the engine continues to run .The differences of the two intenal combustion engineIt could be assumed that a two-cycle engine with the same number of cylinders ,the same displacement ,compression ratio ,and speed as a four-cycle engine would have twice the power since it has twice as many power .However ,this is not the case ,since both the power and compression strokes are shortened to allow scavenging to take place .Thetwo-cycle engine also requires a blower ,which takes engine power to drive .About 160 degrees out of each 360 degrees of crankshaft rotation are required for exhaust gas expulsion and fresh air intake (scavenging )in a two-cycle engine .About 415 degrees of each 720 degrees of crankshaft rotation in a four-cycle engine are required forintake and exhaust .These figures indicate that about % of crank rotation is used for the power producing events in the two-cycle engine ,while about 59% of crank rotation is used for these purposes in the four-cycle engine .Friction losses are consequently greater in the four-cycle engine .Heat losses ,however ,are greater in the two-cycle engine though both the exhaust and the cooling systems .In spite of these differences ,both engine types enjoy prominent use worldwide .Engine constructionCylinder Block:The cylinder block is cast in one piece. Usually, this is the largest and the most complicated single piece of metal in the automobile.The cylinder block is a complicated casting made of gray iron (cast iron ) or aluminum. It contains the cylinders and the water jackets that surround them. To make the cylinder block, a sand form called a mold is made. Then molten metal is poured into the mold. When the metal has cooled the sand mold is broken up and removed. This leaves the tough cylinder-block casting. The casting. The casting is then cleaned and machined to make the finished block.Cylinder blocks for diesel engines are very similar to those for spark-ignition engines. The basic difference is that the diesel-engine cylinder block is heavier and stronger. This is because of the higher pressures developed in the diesel-engine cylinders.Several engines have aluminum cylinder blocks. Aluminum is relatively light metal, weighing much less than cast iron. also ,aluminum conducts heat more rapidly than cast soft to use as cylinder wall material. It wears too rapidly. Therefore, aluminum cylinder blocks must have cast-iron cylinder liners or be cast from an aluminum alloy that has silicon particles in it.Some manufactures make an aluminum cylinder block that does not have cylinder liners, or sleeves. Instead ,the aluminum is loaded with silicon particles. Silicon is a very hard material. After the cylinder block is cast, the cylinders are honed. Then they are treated with a chemical that etches eats away, the surface aluminum. This leaves only the silicon particles exposed. the piston and rings slide on the silicon with minimum wear. Piston:The piston converts the potential energy of the fuel into the kinetic energy that turns the crankshaft. The piston is a cylindrical shaped hollow part that moves up and down inside the engine’s cylinder. It has grooves around its perimeter near the top where thering are placed. The piston fits snugly in the cylinder. It has grooves around its perimeter near the top where the rings are placed. The piston fits snugly in the cylinder. The pistons ate used to ensure a snug “air tight” fit.The piston in your engine’s cylinder are similar to your legs when you ride a bicycle. Think of your legs as pistons; they go up and down on the pedals, providing power. Pedals are like the connecting rods; they are “attached”to your legs. The pedals are attached to the bicycle crank which is like the crank shaft, because it turns the wheels.To reverse this, the pistons (legs) are attached to the connecting rods ( pedals ) which are attached to the crankshaft (the bicycle rank). The power from the combustion in the cylinders powers the from the combustion rods to turn the crankshaft. Connecting rod：The connecting rod shown in is made of forged high strength steel. It transmits force and motion from the piston to the crank pin on the crankshaft. A steel piston pin, or “wrist pin”, connects the small end of the connecting rod. Some rods have a lock bolt in the small end. As the piston moves up and down in the cylinder, the pin rocks back and forth in the hole, or bore, in the piston. The big end of the connecting rod is attached to a crank pin by a rod bearing cap.Connecting rod and rod-bearing caps are assembled during manufacture. Then the hold for the bearing is bored with the cap in place. This is called line-bring. It make each rod and its cap a matched set. Usually, the same number is stamped on the rod and cap. This prevents the caps setting mixed during engine service. If the caps are mixed, the bearing bore will not be round. An engine assembled with the rod bearing caps switched will probably lock the crankshaft. If the crankshaft turns, the bearing will probably have improper clearance and early bearing failure will result.Another reason for keeping the cap and rod matched is to prevent engine unbalance and unwanted vibration. All connecting rods in an engine must be as light as possible. But they must all weigh the same. If one rod is heavier than the other, the engine will vibrate. This could damage the engine.Crankshaft：The crankshaft then main rotating member, or shaft, in the engine. It has crank-pins, to which the connecting rod from the pistons are attached. During the power strokes, the connecting rods force the crank-pins and therefore the crankshaft to rotate. The reciprocating motion of the pistons is changed to rotary motion as the crankshaft spins. This rotary motion is transmitted through the power train to the car wheels.The crankshaft is a strong, one-piece casting, or forging, or heat-treated alloy steel. It must be strong to take the downward force of power strokes without excessive bending. It must be balanced so the engine will run without excessive vibration.Engine DisplacementThe frequently used engine specifications are engine displacement and compression ratio .Displacement and compression ration are related to each other ,as we will learn in the following paragraphs .By Displacement Engine displacement is the amount of air displaced by the piston when it moves fro .The electrical ignition system causes a spark across the spark plug electrodes in the cylinder at the end of the compression stroke ,which ignites the vaporized fuel and air mixture .m compressing the air to ignite the fuel when it is injected into the cylinder at the end of the compression ratios are much higher than gasoline engine compression ratios ,sufficient heat is generated by compressing the air to ignite the fuer of cylinders .engines are classified as low ,medium ,high ,and super high speed .Commonly used to indicate engine size ,this specification is really a measurement of cylinder volume ..The number of cylinders is a factor in determining displacement ,but the arrangement of the cylinders or valves is not .Engine displacement is calculated by multiplying the number of cylinders in the engine by the total engine displacement is the volume displaced by all the pistons .The displacement of one cylinder is the space through which the piston’s top surfa ce moves as it travels from the bottom of its stroke (bottom dead center )to the top of its stroke (top dead center ).It is the volume displaced by the cylinder by one piston stroke .Piston displacement can be calculated as follows :the bore (cylinder Diameter )by gives you the radius of the bore .the radius (multiply it by itself ).the square of the radius by (pi orπ)to find the area of the cylinder cross section .the area of the cylinder cross section by the length of the stroke .You now know the piston displacement for one cylinder .Multiply this by the number of cylinders to determine the total engine displaceme`nt .The formula for the complete procedure reads :R2*π*stroke* cylinders =displacementCompression RatioThis specification compares the total cylinder volume to the volume of only the combustion cylinder volume may seem to be the same as piston displacement ,but it is not .Total cylinder volume .The combustion chamber volume with the piston at top dead center is often called the clearance volume .Compression ratio is the total volume of a cylinder divided by its clearance volume .If the clearance volume is one-eighth of the total cylinder volume ,the compression ratio is 8 (8to1).The formula is as follows :olumeClearancev e Totalvolum =Compression ratio. In theory ,the higher the compression ratio ,the greater the efficiency of the engine ,and the more power an engine will develop from a given quantity of fuel .The reason for this is that combustion takes place faster because the fuel molecules are more tightly packed and the flame of combustion travels more rapidly .But there are practical limits to how high a compression ratio can be .Because of the unavailability of high octane fuel ,most gasolineburning engines are restricted to a compression ratio no greater than to this high ,however ,create high combustion chamber temperatures .This in turn creates oxides of nitrogen (NOx) ,a primary air pollutant .In the early 1970s ,compression ratios were lowered to around 8 to permit the use of lower octane low-lead or unleaded fuel ,and to reduce NOx formation .Advances in electronic engine control in the 1980s have allowed engineers to raise compression ratios to the 9and 10 to 1 range for optimum performance and economy发动机概述发动机是汽车的动力源。
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附录附录A：Research on orbital cold forging for the edge cam of automobile fuel injection pumpABSTRACT: The experimental investigation and theoretical analysis of an orbital cold forging of an edge cam was explored. The effects of blank shape and the process parameters on the edge cam forming are discussed. Photoplastic technology was successfully applied to the simulation of an orbital cold forging process applied to an edge cam. The China-made polycarbonate (PCBA) was used as a simulation material, and a 3-D strain distribution was obtained inside the model materials, which provided theoretical guidance for optimizing process parameters on the orbital cold forging of the edge cam. The factors that caused a crack were identified and the deformation laws in orbital cold forging of an edge cam were clarified. The metal flow line, hardness, microstructures and accuracy of the orbital cold forged edge cam were found to meet the required service properties of the product.Keywords: Orbital cold forging, edge cam, photoplasticity, simulation1. INTRODUCTIONThe edge cam of the automobile fuel injection pump is a key part with complicated shape and high precision, encountered high contact stress and a high shearing stress. It is hard to be made by the conventional forming processes or machining processes, and it doesn’t meet service properties of the product. The structural character and the forming property of materials of the edge cam were analyzed. Orbital cold forging is a forging process where a fixed bottom die and a moveable/orbiting top punch come together to form complex geometric workpieces with finished dimensional accuracy in a single forging operation. The orbiting upper die rolls over a metal blank while the bottom die is raised hydraulically. The billet is kneaded into the bottom die with relatively little force to produce a Near Net Shape or finished workpiece. This process features the orbiting upper die. Due to this orbiting motion over the workpiece, the resultant localized forces can achieve a high degree of deformation at a relatively low force level. As per the adjacent diagram, the forming force required, compared to conventional forming, is much lower due to a smaller contact area.2. EXPERIMENT2.1 Experimental equipmentThe orbital forging press—Type PXWP-100C with capacity of 1600KN was employedfor forming experiment. The orbital head completes 200 revolutions per minute. The inclined angle of the orbital head is adjustable 0° to 2° and there are four orbits selectable: circle, straight, spiral and daisy.2.2 Selecting the blank shapeThe geometric shape of the blank influences greatly the filling performance and the die life of orbital cold forged parts. If the selection is incorrect, it would either damage the die or make the work piece formation unsuccessful. According to the characteristic of the geometric shape of the edge cam, three kinds of blank shape were adopted to test.Blank a) with the step and flange:The size of the protruding step of blank with the function of fixing position in the lower die is basically same as the size of the edge cam. The shape of the edge cam can be formed by the orbital forging with small deformation.Cylindrical blank b) with small step:The size of the protruding step of blank with the function of fixing position in the lower die is basically same as the size of the edge cam. The shape of the edge cam can be formed by the orbital forging with large deformation.Cylindrical blank c):By the outside diameter of the cylindrical blank to fix position in the lower die, the shape of whole edge cam can be formed by the orbital forging with large deformation.All three types of blanks can be successfully formed to the edge cam. Although the deformation of blank a) and blank b) are easier to form than the blank c), the blank a) and the blank b) require being preformed in mass production, thus it will incur high costs. In contrast, although the deformation of the blank c) is higher, its geometric shape is much simpler. Preforming is not a necessary process for blank c). It is suitable for mass production.The work hardening of material plays a very important part in orbital cold forging. So to avoid the surface cracking of the blank in orbital cold forging, the softening annealing and good lubricating for blank are very much required. The orbital cold forging process for the edge cam is as below:Blank——Spheroidizing annealing ——Baiting——Phosphating and soap treatment——Orbital cold forging.2.3 Selecting orbital cold forging ParametersIf the orbit is a circle, the angle of oscillation can range from 0° to 2°. Once the angle is decided, the movement of the rocker will be not changed. If the angle is larger, the area between the rocker and work piece surface is also decreased, so the required deformation force is rather less, the forming time shorter. While a larger angle can bring higher efficiency, the accuracy of the parts will also be affected. This type of orbit is suited forproducing axisymmetrical parts. If the spiral orbit is selected, orbital forging will be helpful for the radial and axial flow of the metal, and also has a better centre deformation; this rocker will apply action cyclically to the central area of the blank. So it is easy to form a part with a much complicated end face. Selecting a linear orbit, it will be easier to form a longer part such as hammer and chisel. If a daisy orbit is selected, the part with tooth profile such as bevel gear and jaw clutch will be formed more easily.The angle of oscillation directly influences the deformation resistance and metal flow, the deformation resistance of theorbital cold forging is calculated as formula below:Where: S—— feed per revolution, mm/r；R—— maximum radius of the orbital cold forged part;γ—— angle of oscillation;σs—— yield strength of materials;K ——influence coefficient of the friction, the inhomogeneous distribution of stress and the shape of forged part etc.For the edge cam, S=1.2 mm/r; γ= 2°, σs=700 N/mm2 (the average yield strength of material 20CrMo), K=1.8, R=32.5mm，So, P=1444KN.Thus, if the angle of oscillation is increased, the loading force is decreased, this is helpful for the radial flow of the metal. The maximum angle of oscillation 2° was applied for orbital cold forging of the edge cam. According to the characteristics of the edge cam’s geometric shape and the type of orbit, the circular motion of the orbital head is selected.The process trial proves the filling property of metal is better, and the clear top & bottom faces of the edge cam was obtained.The lower die of orbital cold forging is generally very highly stressed. The lower die of orbital cold forging is similar to extrusion die. The lower die of orbital cold forging for the edge cam is reinforced by two stress rings. The lower die of orbital cold forging with axially-split inset was employed so as to minimize dangerous stress concentrations.In order to prevent the curve surface and the protruding step of the edge cam from being worn down and a fracture failure, a mobile core is employed in the process, and then an ejector is used to push the forged part out after it is being formed.3. PHOTOPLASTIC SIMULATIONOrbital cold forging deformation for the edge cam was studied with a photoplastic method. The model blank of photoplastic simulation need not to be split before forming. So the defects which the approximate portion of other experimental simulation methods is toolarge in studying the large deformation are avoided for photoplastic method. The photoplastic method can directly give us a set of the difference lines of equal principal strain, and a set of the direction tracks of principal strain in the model. It has many advantages such as: the strain diagram was directly perceived through the senses, and it’s reality, high measuring precision and high sensitivity. It is convenient for data collection, and provides a good way to study the plastic deformation which reflects the real situation.The China made polycarbonate (PCBA) was used as a simulation material. The blank size of the model material (PCBA) was same as the blank size of the edge cam. The blank of the model material was directly orbital cold forged. The full-field strain distribution for orbital cold forging deformation was indirectly obtained by the similarity relationship.The full-field strain distribution which is on the section with height of 17mm along the Z axial direction of the edge cam for orbital cold forging.From the strain distribution diagram, it was observed in the deformation of the edge cam, that the εZ of intermediate zone is compression strain, the radial strain εr and the tangential strain εθ of intermediate zone are tension strain where r≈10mm. This is identical with ordinary cylinder upsetting, and the fluctuation of strain value is low. But the fluctuation of strain value is higher where the intermediate zone r>10mm. It indicates that the deforming zone is inhomogeneous deformation. The max.radial strain εr was attained and the lar ger tangential strain εθ was also attained where r=25mm. As a result, the cracks occur easily in this zone. This is consistent with the cracks occurrence of orbital cold forging of the edge cam. The strain distribution of each Z axis section and deformation rules can be seen from the strain distribution diagram in orbital cold forging of the edge cam, such as the cracks occur easily in the maximal tension strain zone. The deformation homogeneity and detailed deforming of each deformation zone can be explored by the fluctuation of each strain value. It provides experimental basis for keeping defects of deformation cracks from happening, and fixing quantify datum for process experimental analysis. Thereby correct metal deformation laws were obtained in orbital cold forging of the edge cam.4. RESULT AND ANALYSISUpon the completion of optimizing the process parameters, orbital forging of the edge cam analysis and experimental trials, the qualified orbital forged edge cam was obtained.The microstructure of blank (Spheroidizing annealed condition) is composed of ferrite and pearlite.After blank forging, the grain is elongated and distorted. It takes on the obvious fiber structure, and the crystal boundary and the slip line can’t be identified. Thus the grains we re fragmentized in orbital forging of the edge cam, the amount of recrystallizing nucleus wereincreased in the subsequent heat treatment.The interior zone of the edge cam is free from any defects. But the metal flow line of the machining made edge cam is cut off. The brinell hardness of blank (annealed condition) is 130-135HB on average, after deformation, as result of work hardening, the highest hardness of the edge cam reaches to 287HV, a 110% increase. The hardness distribution of the edge cam isn’t u niform. The hardness of the edge cam is higher where the strain is higher. This is consistent with experimental simulation and physical measurement. It indicates that the mechanical property of the edge cam by orbital cold forging is better than the machining made edge cam. The work hardening of the material caused by orbital cold forming increases tensile strength and hardness of the edge cam. The wear resistant property of the edge cam was greatly improved.5. CONCLUSIONSUpon the completion of the research on the orbital cold forging of the edge cam, the following conclusions are drawn:(1) The complicated 3D curved parts with finished dimensional accuracy such as the edge cam of automobile can be formed in a single forging operation.(2) The photoplastic technology can be applied to simulation of orbital cold forging process of the edge cam.(3) The photoplastic technology gives us a theoretical basis for further exploration on orbital cold forging process, as well as the selection of the optimization process parameters.(4) The metal flow line, hardness and metallographic structure of the orbital forged edge cam meet the service performance, which is better than machining made part.(5) In comparison with hot precision forging, the orbital cold forging of the edge cam can save 1/3 of the material consumption, and the productivity increases by over five times. In comparison with machining, the orbital cold forging of the edge cam can save 2/3 of the material consumption, and the productivity increases by over ten times.附录B：关于汽车喷油泵端面凸轮轨道冷锻的研究摘要:对试验研究和理论分析的端面凸轮机构轨道冷锻进行了探讨。