机械类外文文献
机械设计专业外文文献翻译
机械设计专业外文文献翻译general。
however。
materials that are easy to machine have high machinability。
while those that are difficult to machine have low XXX。
microstructure。
and mechanical properties。
as well as the XXX。
material。
and wear resistance.XXX factors。
cutting speed。
feed rate。
and depth of cut also play XXX the amount of heat generated in the cutting zone and decreasing the time that the cutting tool is in contact with the XXX。
at high cutting speeds。
tool wear and cutting forces can increase。
which can ce tool life and surface finish quality.Feed rate and depth of cut also XXX the amount of material that is removed and the forces that are generated during cutting。
Higher feed rates and deeper cuts can improve material removal rates。
but they can also increase cutting forces and heat n。
which can ce tool life and surface finish quality.Overall。
机械类外文文献及翻译
机械类外文文献及翻译(文档含中英文对照即英文原文和中文翻译)原文：GEAR AND SHAFT INTRODUCTIONAbstract:The important position of the wheel gear and shaft can't falter in traditional machine and modern machines.The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box. The passing to process to make them can is divided into many model numbers, using for many situations respectively. So we must be the multilayers to the understanding of the wheel gear and shaft in many ways .Key words: Wheel gear; ShaftIn the force analysis of spur gears, the forces are assumed to act in a single plane. We shall study gears in which the forces have three dimensions. The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. And in the case ofbevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn.Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid.The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement. In spur gears the line of contact is parallel to the axis of the rotation; in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side by side on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft, the hand of the gears should be selected so as to produce the minimum thrust load.Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power. There is on difference between a crossed heli : cal gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand; that is ,a right-hand driver goes with a right-hand driven. In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle areequal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand.Worm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm gear are used to provide a high angular-velocity reduction between nonintersecting shafts which are usually at right angle. The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact. However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed helical gears.Worm gearing are either single or double enveloping. A single-enveloping gearing is onein which the gear wraps around or partially encloses the worm.. A gearing in which each element partially encloses the other is, of course, a double-enveloping worm gearing. The important difference between the two is that area contact exists between the teeth of double-enveloping gears while only line contact between those of single-enveloping gears. The worm and worm gear of a set have the same hand of helix as for crossed helical gears, but the helix angles are usually quite different. The helix angle on the worm is generally quite large, and that on the gear very small. Because of this, it is usual to specify the lead angle on the worm, which is the complement of the worm helix angle, and the helix angle on the gear; the two angles are equal for a 0-deg. Shaft angle.When gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required. Although bevel gear are usually made for a shaft angle of 0 deg. They may be produced for almost any shaft angle. The teeth may be cast, milled, or generated. Only the generated teeth may be classed as accurate. In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing. This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth. Another difficulty, which occurs in predicting the stress in bevel-gear teeth, is the fact the teeth are tapered.Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively. As in the case of squr gears, however, they become noisy at higher values of the pitch-line velocity. In these cases it is often go : od design practice to go to the spiral bevel gear, which is the bevel counterpart of thehelical gear. As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered.It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset. Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution. The tooth action between such gears is a combination of rolling and sliding along a straight line and has much in common with that of worm gears.A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other power-transmission elements. Shaft may be subjected to bending, tension, compression, or torsional loads, acting singly or in combination with one another. When they are combined, one may expect to find both static and fatigue strength to be important design considerations, since a single shaft may be subjected to static stresses, completely reversed, and repeated stresses, all acting at the same time.The word “shaft” covers numerous v ariations, such as axles and spindles. Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load. A shirt rotating shaft is often called a spindle.When either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of deflection before analyzing the stresses. The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe. But by no means should the designer assume that they are safe; it is almost always necessary to calculate them so that he knows they are within acceptable limits. Whenever possible, the power-transmission elements, such as gears or pullets, should be located close to the supporting bearings, This reduces the bending moment, and hence the deflection and bending stress.Although the von Mises-Hencky-Goodman method is difficult to use in design of shaft, it probably comes closest to predicting actual failure. Thus it is a good way of checking a shaft that has already been designed or of discovering why a particular shaft has failed in service. Furthermore, there are a considerable number of shaft-design problems in which the dimension are pretty well limited by other considerations, such as rigidity, and it is only necessary for the designer to discover something about the fillet sizes, heat-treatment,and surface finish and whether or not shot peening is necessary in order to achieve the required life and reliability.Because of the similarity of their functions, clutches and brakes are treated together. In a simplified dynamic representation of a friction clutch, or brake, two in : ertias I and I traveling at the respective angular velocities W and W, one of which may be zero in the case of brake, are to be brought to the same speed by engaging the clutch or brake. Slippage occurs because the two elements are running at different speeds and energy is dissipated during actuation, resulting in a temperature rise. In analyzing the performance of these devices we shall be interested in the actuating force, the torque transmitted, the energy loss and the temperature rise. The torque transmitted is related to the actuating force, the coefficient of friction, and the geometry of the clutch or brake. This is problem in static, which will have to be studied separately for eath geometric configuration. However, temperature rise is related to energy loss and can be studied without regard to the type of brake or clutch because the geometry of interest is the heat-dissipating surfaces. The various types of clutches and brakes may be classified as fllows:. Rim type with internally expanding shoes. Rim type with externally contracting shoes. Band type. Disk or axial type. Cone type. Miscellaneous typeThe analysis of all type of friction clutches and brakes use the same general procedure. The following step are necessary:. Assume or determine the distribution of pressure on the frictional surfaces.. Find a relation between the maximum pressure and the pressure at any point. Apply the condition of statical equilibrium to find (a) the actuating force, (b) the torque, and (c) the support reactions.Miscellaneous clutches include several types, such as the positive-contact clutches, overload-release clutches, overrunning clutches, magnetic fluid clutches, and others.A positive-contact clutch consists of a shift lever and two jaws. The greatest differences between the various types of positive clutches are concerned with the design of the jaws. To provide a longer period of time for shift action during engagement, the jaws may be ratchet-shaped, or gear-tooth-shaped. Sometimes a great many teeth or jaws are used, and they may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of the mating elements.Although positive clutches are not used to the extent of the frictional-contact type, they do have important applications where synchronous operation is required.Devices such as linear drives or motor-operated screw drivers must run to definite limit and then come to a stop. An overload-release type of clutch is required for these applications. These clutches are usually spring-loaded so as to release at a predetermined toque. The clicking sound which is heard when the overload point is reached is considered to be a desirable signal.An overrunning clutch or coupling permits the driven member of a machine to “freewheel” or “overrun” bec ause the driver is stopped or because another source of power increase the speed of the driven. This : type of clutch usually uses rollers or balls mounted between an outer sleeve and an inner member having flats machined around the periphery. Driving action is obtained by wedging the rollers between the sleeve and the flats. The clutch is therefore equivalent to a pawl and ratchet with an infinite number of teeth.Magnetic fluid clutch or brake is a relatively new development which has two parallel magnetic plates. Between these plates is a lubricated magnetic powder mixture. An electromagnetic coil is inserted somewhere in the magnetic circuit. By varying the excitation to this coil, the shearing strength of the magnetic fluid mixture may be accurately controlled. Thus any condition from a full slip to a frozen lockup may be obtained.齿轮和轴的介绍摘要:在传统机械和现代机械中齿轮和轴的重要地位是不可动摇的。
机械工程专业外文文献及翻译
机械工程专业外文文献及翻译文献一（外文标题）
摘要：
该文献研究了机械工程领域中的某个具体问题。
通过实验方法和数学模型的分析，作者得出了一些有意义的结论。
本文介绍了作者的研究方法和结果，并讨论了其在机械工程领域的应用前景。
翻译：
（将文献的主要内容用简洁准确的语言翻译成中文）
文献二（外文标题）
摘要：
该文献探讨了机械工程领域中的另一个重要问题。
通过实证分析和理论推导，作者提出了解决方案，并对其进行了验证。
本文阐述了作者的方法和实验结果，并探讨了其在实践中的应用潜力。
翻译：
（将文献的主要内容用简洁准确的语言翻译成中文）
文献三（外文标题）
摘要：
该文献研究了机械工程领域中的另一个新颖课题。
作者通过数
值模拟和实验验证，得出了一些有趣的发现。
本文介绍了作者的研
究过程和结果，并讨论了其对机械工程领域的影响。
翻译：
（将文献的主要内容用简洁准确的语言翻译成中文）
总结
本文档介绍了三篇机械工程专业的外文文献，包括摘要和翻译。
这些文献都对机械工程领域中的不同问题进行了研究，并提出了相
关的解决方案和发现。
希望这些文献能为机械工程专业的学生和研
究人员提供有价值的参考和启发。
机械外文文献及翻译
与机械相关的外文及翻译Multidisciplinary Design Optimization of Modular Industrial Robots by Utilizing High Level CAD Templates1、IntroductionIn the design of complex and tightly integrated engineering products, it is essential to be able to handle interactions between different subsystems of multidisciplinary nature [1]. To achieve an optimal design, a product must be treated as a complete system instead of developing subsystems independently [2]. MDO has been established as a convincing concurrent design optimization technique in development of such complex products [3,4].Furthermore, it has been pointed out that, regardless of discipline, basically all analyses require information that has to be extracted from a geometry model [5]. Hence, according to Bow-cutt [1], in order to enable integrated design analysis and optimization it is of vital importance to be able to integrate an automated parametric geometry generation system into the design framework. The automated geometry generation is a key enabler for so-called geometry-in-the-loop[6] multidisciplinary design frameworks, where the CAD geometries can serve as framework integrators for other engineering tools.To eliminate noncreative work, methods for creation and automatic generation of HLCt have been suggested by Tarkian [7].The principle of high HLCts is similar to high level primitives(HLP) suggested by La Rocca and van Tooren [8], with the exception that HLCts are created and utilized in a CAD environment.Otherwise, the basics of both HLP and HLCt can, as suggested byLa Rocca, be compared to parametric LEGOV Rblocks containing a set of design and analysis parameters. These are produced and stored in libraries, giving engineers or a computer agent the possibility to first topologically select the templates and then modify the morphology, meaning theshape,of each template parametrically.2、Multidisciplinary Design FrameworkMDO is a “systematic approach to design space exploration”[17], the implementation of which allows the designer to map the interdisciplinary relations that exist in a system. In this work, the MDO framework consists of a geometry model, a finite element(FE) model, a dynamic model and a basic cost model. The geometry model provides the analysis tools with geometric input. The dynamic model requires mass properties such as mass, center of gravity, and inertia. The FE model needs the meshed geometry of the robot as well as the force and torque interactions based on results of dynamic simulations.High fidelity models require an extensive evaluation time which has be taken into account. This shortcoming is addressed by applying surrogate models for the FE and the CAD models. The models are briefly presented below. 2.1 High Level CAD Template—Geometry ModelTraditionally, parametric CAD is mainly focused on morphological modifications of the geometry. However, there is a limit to morphological parameterization as follows:•The geometries cannot be radically modified.•Increased geometric complexity greatly increases parameterization complexity.The geometry model of the robot is generated with presaved HLCts, created in CATIA V5. These are topologically instantiated with unique internal design variables. Topological parameterization allows deletion, modification, and addition of geometricelements which leads to a much greater design space captured.Three types of HLCts are used to define the industrial robot topologically; Datum HLCt which includes wireframe references required for placement for the Actuator HLCTs and Structure HLCts, as seen Fig.2.Fig. 2 An industrial robot (left) and a modular industrial robot(right) The names of the references that must be provided for each HLCt instantiation are stored in the knowledge base (see Appen-dix A.4), which is searched through by the inference engine. In Appendix A, pseudocode examples describes how the references are retrieved and how they are stored in the knowledge base.The process starts by the user defining the number of degrees of freedom (DOF) of the robot (see Fig. 3) and is repeated until the number of axis (i) is equal to the user defined DOF.In order to instantiate the first Structure HLCt, two Datum and two actuator instances are needed. References from the two Datum instances help orienting the structure in space, while the geometries of the actuator instances, at both ends of the link, are used to construct the actuator attachments, as seen in Figs. 2 and 3. For the remaining links, only one new instance of both datum and actuator HLCts are required, since the datum and actuator instances from adjacent links are already available.Appendix A.2 shows a pseudocode example of an instantiation function. The first instantiated datum HLCt is defined with reference to the absolute coordinate system. The remaining datum HLCt instances are placed in a sequential order, where the coordinate system of previous instances is used as reference for defining the position in space according to user inputs (see also AppendixA.3). Furthermore, the type of each actuator and structure instance is user defined.Fig. 3 The high level CAD template instantiation process Since it is possible to create new HLCts in the utilized CAD tool, the users are not forced to merely choose from the templates available. New HLCts can be created, placed in the database and parametrically inserted into the models.2.2 Dynamic ModelThe objective of performing dynamic simulation of a robot is to evaluate system performance, such as predicting acceleration and time performance, but it also yields loads on each actuated axis, needed for actuator lifetime calculations and subsequent stress analysis based on FE calculations. Thedynamic model in the outlined framework is developed in Modelica using Dymola, and it constitutes a seven-axis robot arm based on the Modelica Standard library [18].The dynamic model receives input from the geometry model,as well as providing output to the FE model, which is further described in Sec. 2.3. However, to better understand the couplings between the models, the Newton –Euler formulation will be briefly discussed. In this formulation, the link velocities and acceleration are iteratively computed, forward recursivelyWhen the kinematic properties are computed, the force and torque interactions between the links are computed backward recursively from the last to the first link2.3 FE Surrogate ModelTo compute the structural strength of the robot, FE models for each robot link is created utilizing CATIA V5, see Fig. 4. For each HLCt, mesh and boundary conditions are manually preprocessed in order to allow for subsequent automation for FE-model creation. The time spent on preprocessing each FE-model is thus extensive. Nonetheless, the obtained parametric FE-model paves way for automated evaluation of a wide span of concepts. Each robot link is evaluated separately with the load conditions extracted from the dynamicmodel. The force (fi-11and fi) and torque (ţi-1and ti) are applied on the surfaceswhere the actuators are attached.2.4 Geometric Surrogate Models.Surrogate models are numerically efficient models to determine the relation between inputs and o utputs of a model [19]. The input variables for the proposed application are the morphological variables thickness and link height as well as a topological variable actuator type. The outputs of the surrogate models are mass m, Inertia I, and center of gravity ri,ci.To identify the most suitable type of surrogate model for the outlined problem, a range of surrogate models types are created and evaluated using 50 samples. The precision of each surrogate model is compared with the values of the original model with 20 new samples. The comparison is made using the relative average absolute error (RAAE) and relative maximum absolute error (RMAE) as specified by Shan et al. [20], as well as the normalized root mean square error (NRMSE), calculated as seen in Eq. (3). All precision metrics are desired to be as low as possible, since low values mean that the surrogate model is accurateThe resulting precision metrics can be seen in Appendix B and the general conclusion is that anisotropic kriging [21], neural networks [22], and radialbasis functions [23] are the most promising surrogate models. To investigate the impact of increasing number of samples, additional surrogate models of those three are fitted using 100 samples, and the results compiled in Appendix B. The resulting NRMSEs for 50 and 100 samples for anistotropic kriging, neural networks, and radial basis functions can be seen in Fig.5. The figures inside the parentheses indicate the number of samples used to fit the surrogate models.Fig. 5 Graph of the NRMSEs for different surrogate models,fitted using 50 and 100 samplesAccording to Fig. 5, anisotropic kriging outperforms the other surrogate models and the doubling of the number of samples usedfor fitting the surrogate model increases the precision dramatically.2.5 FE Surrogate ModelsFor generating FE surrogate models, the anisotropic kriging was also proven to be the most accurate compared to the methods evaluated in Sec. 2.4. Here, one surrogate model is created for each link. Inputs are thickness,actuators, force (fi-11and fi) and torque (ţi-1and ti). The output for eachsurrogate model is maximum stress (MS).A mean error of approximately 9% is reached when running 1400 samples for each link. The reason for the vast number of samples, compared to geometry surrogate models, has to do with a much larger design space.利用高水平CAD模板进行模块化工业机器人的多学科设计优化1 介绍指出,除了规则,基本上所有的分析都需要信息,而这些信息需要从一个几何模型中提取。
机械设计方面的外文参考文献
Set of NN weights w!p) li=1, ... ,NW;p=l, ... ,L
Stage III Computation of membership functions for NN weights
FuzyNN with weights membership functions Pi = p(w~p»
inequalities (l-2KIL)::;; IX < (l-2(K-I)/L , where: K = kLa . Ita - numbers of
weight values on the left or right hand sides of w, respectively. In case of a E
There are three possibilities to formulating fuzzy networks. The first one corresponds to the neural network with crisp parameters (called for short NN weights) and performing computations on interval variables [8]. Much advanced are NNs with crisp inputs and outputs but their processing is performed on fuzzyfied variables with fuzzy reasoning rules, cf. fuzzy inference systems [4]. The third class is associated with full fuzzification of transmitted signals, NN weights and neurons of a fuzzy NN [2]. A more numerically efficient approach depends on joining simple membership functions of signals and NN parameters with interval arithmetics [7].
机械工程-外文文献
The content of mechanical engineeringMechanical engineering services and multi-faceted, who use machinery, tools, and energy and material production department of mechanical engineering, need the service. The summary mentions, modern machinery engineering has five services: development and provide energy conversion, and provide for mechanical manufacturing all kinds of products and machinery, provide various services in the machinery, the development and provide family and personal life, the development and the application of the machines provide various mechanical weapons.Regardless of what a field service to the working content of mechanical engineering, basic and same, mainly include:The establishment and development of mechanical engineering construction and theoretical basis. For example, research force and motion and fluid mechanics, engineering mechanics, Metallic and non-metallic materials to study the performance, and its application in engineering materials, The heat conduction, research and conversion of thermodynamics, All kinds of mechanical components are independent of the function of the working principle, structure, design and calculation of mechanical principle and mechanical parts; Study of metallic and nonmetallic machining and forming technology of metal and technology, etc.Research, design and development of new products and continuously improving existing machine mechanical products and new generation of mechanical products, in order to adapt to the current and future needs.Mechanical products production, including: the planning and production facilities, Production plan and production scheduling, Prepare and implement manufacturing process, Design and manufacturing tools, moulds, Determine the quota and material quota, Organization processing, assembling and commissioning and package delivery, For product quality effectively control. Mechanical manufacturing enterprise operation and management. Mechanical general is composed of many each have unique shape, processing precision parts assembled into a complex products. Production batch have single piece and small batch, also have a large batch, until production. Throughout the entire industry and sales target individual, family. And sales in the social and economic situations, may appear under the influence of the big wave. Therefore, mechanical manufacturing enterprise management and operation of enterprises, especially complex production management, planning and management of research are also began in machinery industry.The application of mechanical products. This includes selection, order, acceptance, installation, adjustment and operation, maintenance, repair and transformation of the industry by use of machinery and complete sets of equipment, to ensure the long-term use of mechanical products in the reliability and efficiency.The application of mechanical products. This includes selection, order, acceptance, installation, adjustment and operation, maintenance, repair and transformation of the industry by use of machinery and complete sets of equipment, to ensure the long-term use of mechanical products in the reliability and efficiency.Research in the manufacturing process of mechanical products, especially in the use of the natural resources and environmental pollution, excessive consumption issues, andtreatment measures. This is a modern mechanical engineering is particularly important task, and its importance.Mechanical engineering classificationMechanical variety, can according to several different ways into various categories, such as: the function can be divided into mechanical power, material handling machinery, machine etc, According to the service industry could be divided into agricultural machinery, mining machinery, textile machinery, etc. According to the principle of work can be divided into the thermal fluid machinery, mechanical, bionic machine, etc. In addition, machinery in the research, development, design, manufacture, application process to work through several stages of nature. According to the different stage, mechanical engineering and can be divided into each other, with several branches system, such as mechanical research, mechanical design, mechanical manufacturing, mechanical using and maintenance, etc.According to the different aspects of the various branches of system is divided into each other, thus overlap, mechanical engineering may be differentiated into hundreds of branches. For example, according to the function of dynamic mechanical, it points with the working principle of mechanical, thermal fluid machinery, turbine machinery, reciprocating machinery, steam power machinery, nuclear power plant, internal combustion engines, gas turbine, according to industry and the center of power equipment, industrial power plant, locomotives, ship, automobile engineering Marine engineering are complex and overlapping relation. Marine steam turbine power machinery, also is the thermal fluid machinery, mechanical and turbine machinery, it belongs to the Marine power plant, steam power plant, may also belongs to the nuclear power plant etc.The development of mechanical engineeringHumans become "modern" sign is manufacturing tools. The Stone Age, all sorts of this stone hammers and wood, leather simple tools is rough pioneer of the machinery. From a simple tool to make manufacturing by multiple parts, components of modern machinery, experienced a long process.Thousands of years ago, humanity has created a shell and crushed grain used to carry mortar and grinding, the JieGao engineer-in-chief with wheels, with the car, the ship sailing in rivers, buildings, and the rudder. The power from the physical, one's own development, using animal, hydraulic and wind. Materials from the natural stone, wood, clay, leather, synthetic materials development. The earliest artificial material is made of pottery and porcelain, is already has the pottery, transmission and three parts of the complete machine work.Humans from the Stone Age to the Bronze Age, and then to the iron age, to flourish of drum wind blows of the development plays an important role. Have strong enough, the drum wind to get a high enough metallurgical furnace temperature, can have refined metal from ore in. In China, the former 900 years to use the drum for metallurgy, and gradually from the human drum wind to work and hydraulic drum wind.15-16 centuries ago, mechanical engineering development is slow. But in practice, the millennium project in machinery development and has accumulated much experience and technical knowledge, became the mechanical engineering development potential. Since the 17th century, capitalism in the English, French and European countries, commodity production began to become the center of social problems.In the 18th century, the application of steam from mining to textiles, flour, metallurgy, etc. The main material of production machines from wood to use more tough, but with manual processing of metal. Mechanical manufacturing industry, and began to form in the decades to become an important industry.Mechanical engineering through expanding from the practice, the dispersion, mainly depends on the needs of individual talents and craft a skill, gradually develop a theoretical guidance, system and independent engineering technology. Mechanical engineering is 18-19 century and the industrial revolution, the capitalist mechanical production main technological factors.Power is an important factor of the development of production. In the 17th century, along with the development and improvement of machinery, metal ore with coal and the requirements of increased year by year, people feel rely on human and animal will not produce to a new stage.In Britain, textile, grinding industries are increasingly using workshop in the river, will work to drive hydraulic machinery. But when the coal mine, the copper ore, etc, with lots of groundwater is only to ascend and excluded. Animal In this production needs, 18 century appeared newcomen atmospheric type steam, mine drainage pumps to drive. But the steam engine fuel consumption, high, basically applies only to mine.In 1765, watt invented the steam engine have separate condenser, reduce the fuel consumption. 1781 watt and create the steam engine, turning provide motivation of steam expanding the scope of application. The steam engine invented and development, mining and industrial production, railways and shipping to mechanical power. The steam engine was almost in the 19th century, but the only power and steam boiler, condenser, cooling water system huge volume, bulky, application is not easy.19 century, the power supply system, and the development and popularization of motor start. At the beginning of the 20th century, the motor in industrial production has replaced the steam, become the basic mechanical drive all kinds of work. Production mechanization, already from electrification of electrified by mechanization production function.Power for the initial application of the steam engine. In the early 20th century, high efficiency, high speed, high steam turbine, also appeared to water resources of the turbine power supply system, promote the vigorous development.The invention of the late 19th century, has improved combustion through light and small, high efficiency, easy manipulation, and can always start the engine. It is used to drive to work without power supply of land, and mechanical for automobile, mobile machinery and ships, until the middle of 20th century began for locomotives. Steam turbine engine in the crowd, and are no longer important power machinery. After the invention of internal combustion engine and gas turbine, jet engines, is the development of aircraft, such successful development foundation spacecraft technical factor.Before the industrial revolution, mostly of wood, mechanical hand made by the carpenter. Metal (mainly copper, iron) only to manufacture equipment, lock, clocks, pump and mechanical parts of the small wood. Metal processing of the machine mainly by seiko spy, achieves the need of precision. Steam power plant, and the promotion of the mining, metallurgical appears, ships, large machinery development of locomotive, forming and cutting processing of metal parts, growing more and more and more is also high accuracyrequirements. The application of metal materials from copper and iron development to steel.Mechanical processing including forging, forging, sheet metal work, welding, and heat treatment technology and equipment, and machining technology and machine tools, measuring tools, etc, is rapidly developing, ensuring each industry development for production equipment supply.The development of social economy, the demand of mechanical products explosion. Production batch of increase and precision machining technology development, promote the formation of large production methods, such as division of professional production and interchangeability parts and collaboration, water processing line and assembly line etc.Simple interchangeable parts and division of professional production, in ancient collaboration has appeared. In mechanical engineering, the interchangeability embodied in mo for 1797 Bates USES its created by threading lathe of bolts and nuts production. At the same time, the American engineers with interchangeable manufacturing production methods, Whitney, shows the feasibility and superiority of interchangeable. The production methods, in the United States has formed the so-called "American production methods".In the early 20th century, ford car manufacturing and created the assembly line. Mass production technology in the 19th century and Taylor was that the scientific management method, automobile and other mass production machinery production efficiency quickly reached the height of past cannot imagine.In the late 20th century, the main characteristics, mechanical processing, continuously improve the machine is processing speed and accuracy, reducing the dependence of craftsmanship, Improve machining and forming, cutting and assembly of mechanization and automation, Using CNC processing center, the group technology, etc, to develop flexible manufacturing systems, small volume and multiple varieties of production efficiency is to improve the level of production, Study hard and improve the processing of metallic and non-metallic materials, new forming and machining technology.18 centuries ago, mechanical artisan, intuition and experience in mechanical manufacture craft, and almost no scientific association. To 18-19 century, in the emerging of capitalist economy, promote the scientific knowledge of master production, and people start paying attention to direct production needs to start to learn scientific and cultural knowledge, communication between them and made great achievements in mutual inspiration. In this process, and gradually formed a set of basic theory on mechanical engineering.Mechanical power with the advanced scientific combination. The steam engine invented Avery, pizza, applied physicist watt pat Penn and black theory, Based on the practice in the steam engine, physicists cano, LanJinHe kelvin established a new science - thermodynamics. Engine is based on the theory of France in 1862 LuoSha founded, In 1876, the application of theory LuoSha otto thoroughly improve he had created the rough heavy, noise, low efficiency of internal combustion and laid the position. Other such as steam turbine, gas turbine, etc. In theory, and under the guidance of the theory in practice and improvement.In early BC, China has applied the car in guide in complex system of gear was applied to the burner and level of the place turn, etc. Ancient Greece had cylindrical gears, bevel gears and worm transmission. However, the instantaneous speed on gear tooth shape and the relationship of tooth profile curve and the 17th century, until after a theory.The agency's hand and pedal pioneers of crank rod system in the ancient civilization has a long history, but in the form of crank rod system, movement and dynamic analysis and synthesis, exactly is modern organization learning achievements. As a specialized agencies, until the early 19th century in higher engineering college for the technology institute (Paris). Through the theoretical study, people can accurately analysis of various institutions, including the complex space of movement, and then according to need a new comprehensive.Mechanical engineering work object is dynamic mechanical, it will happen. This change is sometimes randomly and unforeseeable, Actual application materials are incomplete, there may be various defects, Machining accuracy has certain deviation, etc.With the static structure for the civil engineering work, mechanical engineering in more difficult problems in theory to solve accurate. Therefore, the early application of mechanical engineering only simple theoretical concept, combined with practical experience. Experience in design and calculation formula for more on, To ensure safety, rather conservative, results of large and heavy machinery, high cost and low productivity, energy consumption.In the 18th century, a new theory of birth, and the development of mathematics method, design calculation precision of continuous improvement. In the 20th century, appear all sorts of experimental stress analysis method, the experimental method to detect with people already on the physical model and the stress. 20 century, and the finite element method and the wide application of electronic computers, which makes the complex machinery and zero. Component force, moment, stress analysis and calculation of such as possible. To master have sufficient practice or experimental dataMechanical or its components, can use statistical techniques, according to the requirements of reliability, mechanical design scientifically.The development of mechanical engineeringTo increase the production of mechanical engineering and improve labor productivity, improve the production efficiency of research and development for the goal to new mechanical products. In the future development of the new products, to reduce the consumption of resources to develop clean and renewable energy, management, reduce and eliminate environmental pollution as super economic goals and tasks.The persons involved with both hands and mechanical can eyes and ears, feet and cannot be directly directly, and finish the job finished faster and better. Modern mechanical engineering to create more and more exquisite and increasingly complex machinery and mechanical device, the past many fantasy to become a reality.Humans can now upstream sky and the universe, diving deep ocean, and nearly 100 million light-years out till the cellular and molecular. The emerging electronic computer hardware and software to strengthen human has begun to replace the brain, and part of the scientific and technological means, this is the artificial intelligence. This is a new development has shown great influence in the future, it will constantly create people cannot imagine the miracle.The growth of human wisdom does not reduce the hands, but instead as more and more delicate hands, more complex, so more promote the function of hand. The practice of hand, in turn, promote the wisdom of the human brain. In the process of evolution of humanity, and the growth of each individual in the process, the brain and the hand is mutual promoting peace line of evolution.Artificial intelligence and the relationship between mechanical engineering in the brain and the hand approximation, the relationship between the difference is only in artificial intelligence will need to use the hardware machinery manufacturing. In the past, all kinds of machinery without man's operating and controlling the reaction speed, accuracy and operating by the brain evolved slowly and nervous system restriction, artificial intelligence will eliminate this restriction. Computer science and mechanical engineering, the mutual promotion between parallel, will make the mechanical engineering at the higher level is the beginning of a new round of development,In the 19th century, mechanical engineering knowledge is limited in European universities and colleges, it is generally for a comprehensive and civil engineering disciplines, civil engineering, called the 19th century has become an independent discipline. In the 20th century, with the mechanical engineering technology development and growth of knowledge, mechanical engineering and began to decompose the specialization of branch appeared. The decomposition of the trend in the middle of the twentieth century, and that in the end of the second world war during peak reached before.Due to mechanical engineering knowledge has been expanded to be far from certain professional master, all is indispensable. But the excessive specialized knowledge, caused by excessive vision narrow orthodoxy and as a whole, not the whole of the project scale slightly, and shrink and technical exchanges, hampering the new techniques and technology progress on the whole, the ability to adapt to the change of external conditions is very poor. Closure of professional experts have acquired knowledge, consider problems in work, had only with difficulty, also coordinate when to self-study. Unfavorable Therefore, since the 20th century, and the comprehensive trend appears. People pay more attention the basic theory, widen the field of merger, division meticulous professional.Comprehensive - professional differentiation - again, is the comprehensive knowledge of the development process of the reasonable and necessary. Different professional experts have different exquisite specialized knowledge, and have enough knowledge to the comprehensive understanding, understanding other subject and overall appearance, can form each other powerful collective work.Comprehensive and professional is mutiple level. In mechanical engineering expertise and internal contradictions are integrated, In the comprehensive engineering technology also has a comprehensive and professional problem. In all human knowledge, including social sciences and natural sciences and the engineering technology, also have a higher layer, in more comprehensive and professional macro problem.。
机械类外文文献
附：外文翻译外文原文：Fundamentals of Mechanical Design Mechanical design means the design of things and systems of a mechanical nature —machines, products, structures, devices, and instruments. For the most part mechanical design utilizes mathematics, the materials sciences, and the engineering-mechanics sciences.The total design process is of interest to us. How does it begin? Does the engineer simply sit down at his desk with a blank sheet of paper? And, as he jots down some ideas, what happens next? What factors influence or control the decisions which have to be made? Finally, then, how does this design process end?Sometimes, but not always, design begins when an engineer recognizes a need and decides to do something about it. Recognition of the need and phrasing it in so many words often constitute a highly creative act because the need may be only a vague discontent, a feeling of uneasiness, of a sensing that something is not right.The need is usually not evident at all. For example, the need to do something about a food-packaging machine may be indicated by the noise level, by the variations in package weight, and by slight but perceptible variations in the quality of the packaging or wrap.There is a distinct difference between the statement of the need and the identification of the problem.Which follows this statement? The problem is more specific. If the need is for cleaner air, the problem might be that of reducing the dust discharge from power-plant stacks, or reducing the quantity of irritants from automotive exhausts.Definition of the problem must include all the specifications for the thing that is to be designed. The specifications are the input and output quantities, the characteristics of the space the thing must occupy and all the limitations on these quantities. We can regard the thing to be designed as something in a black box. In this case we must specify the inputs and outputs of the box together with their characteristics and limitations. The specifications define the cost, the number to be manufactured, the expected life, the range, the operating temperature, and the reliability.There are many implied specifications which result either from the designer ' s particular environment orfrom the nature of the problem itself. The manufacturing processes which are available, together with the facilities of a certain plant, constitute restrictions on a designer ' s freedom, and hence are a part ofthe implied specifications. A small plant, for instance, may not own cold-working machinery. Knowing this, the designer selects other metal-processing methods which can be performed in the plant. The labor skills available and the competitive situation also constitute implied specifications.After the problem has been defined and a set of written and implied specifications has been obtained, the next step in design is the synthesis of an optimum solution. Now synthesis cannot take place without both analysis and optimization because the system under design must be analyzed to determine whether theperformance complies with the specifications.The design is an iterative process in which we proceed through several steps, evaluate the results, and then return to an earlier phase of the procedure. Thus we may synthesize several components of a system, analyze and optimize them, and return to synthesis to see what effect this has on the remaining parts of the system. Both analysis and optimization require that we constructor devise abstract models of the system which will admit some form of mathematical analysis. We call these models mathematical models. In creating them it is our hope that we can find one which will simulate the real physical system very well.Evaluation is a significant phase of the total design process. Evaluation is the final proof of a successful design, which usually involves the testing of a prototype in the laboratory. Here we wish to discover if the design really satisfies the need or needs. Is it reliable? Will it compete successfully with similar products? Is it economical to manufacture and to use? Is it easily maintained and adjusted? Can a profit be made from its sale or use?Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to administrative, management, or supervisory persons, is attempting to sell or to prove to them that this solution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted.Basically, there are only three means of communication available to us. There are the written, the oral, and the graphical forms. Therefore the successful engineer will be technically competent and versatile in all three forms of communication. A technically competent person who lacks ability in any one of these formsis severely handicapped. If ability in all three forms is lacking, no one will ever know how competent that person is!The competent engineer should not be afraid of the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea. There is a great to be learned from a failure, and the greatest gains are obtained by those willing to risk defeat. In the find analysis, the real failure would lie in deciding not to make the presentation at all.Introduction to Machine DesignMachine design is the application of science and technology to devise new or improved products for the purpose of satisfying human needs. It is a vast field of engineering technology which not only concerns itself with the original conception of the product in terms of its size, shape and construction details, but also considers the various factors involved in the manufacture, marketing and use of the product.People who perform the various functions of machine design are typically called designers, or design engineers. Machine design is basically a creative activity. However, in addition to being innovative, a design engineer must also have a solid background in the areas of mechanical drawing, kinematics, dynamics, materials engineering, strength of materials and manufacturing processes.As stated previously, the purpose of machine design is to produce a product which will serve a need for man. Inventions, discoveries and scientific knowledge by themselves do not necessarily benefit people; onlyif they are incorporated into a designed product will a benefit be derived. It should be recognized, therefore, that a human need must be identified before a particular product is designed.Machine design should be considered to be an opportunity to use innovative talents to envision a design of a product is to be manufactured. It is important to understand the fundamentals of engineering rather than memorize mere facts and equations. There are no facts or equations which alone can be used to provide all the correct decisions to produce a good design. On the other hand, any calculations made must be done with the utmost care and precision. For example, if a decimal point is misplaced, an otherwiseacceptable design may not function.Good designs require trying new ideas and being willing to take a certain amount of risk, knowing that is the new idea does not work the existing method can be reinstated. Thus a designer must have patience, since there is no assurance of success for the time and effort expended. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated.New designs generally have “bugs ”or unforeseen problems which must be worked out before the superior characteristics of the new designs can be enjoyed. Thus there is a chance for a superior product, but only at higher risk. It should be emphasized that if a design does not warrant radical new methods, such methods should not be applied merely for the sake of change.During the beginning stages of design, creativity should be allowed to flourish without a great number of constraints. Even though many impractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise.Psychologists frequently talk about trying to fit people to the machines they operate. It is essentially the responsibility of the design engineer to strive to fit machines to people. This is not an easy task, since there is really no average person for which certain operating dimensions and procedures are optimum.Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Initially the designer must communicate a preliminary design to get management approval. This is usually done by verbal discussions in conjunction with drawinglayouts and written material. To communicate effectively, the following questions must be answered:(1) Does the design really serve a human need?(2) Will it be competitive with existing products of rival companies?(3) Is it economical to produce?(4) Can it be readily maintained?(5) Will it sell and make a profit?Only time will provide the true answers to the preceding questions, but the product should be designed, manufactured and marketed only with initial affirmative answers. The design engineer also must communicate the finalized design to manufacturing through the use of detail and assembly drawings.Quite often, a problem well occur during the manufacturing cycle. It may be that a change is required in the dimensioning or telegramming of a part so that it can be more readily produced. This falls in the category of engineering changes which must be approved by the design engineer so that the product function will not be adversely affected. In other cases, a deficiency in the design may appear during assembly or testing just prior to shipping. These realities simply bear out the fact that design is a living process. There is always a better way to do it and the designer should constantly strive towards finding that better way.MachiningTurning The 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 and accuracy, are now at the designer's fingertips with production speeds 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, in terms of ability to repeat accurately and rapidly. Applying 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 turret 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 to set up on the turret lathe than on the automatic screw machine. Quantities less than 1000 parts may be more economical to set up on the turret lathe 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 upon material turned, tooling, andfees and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.Is some case, 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 onboth diameter and length of turn.Milling With the exceptions of turning and drilling, milling is undoubtedly the most widely used method of removing metal. Well suited and readily adapted to the economical production of any quantity of parts, the almost unlimited versatility of the milling process merits the attention and consideration of designers seriously concerned with the manufacture of their product.As in any other process, parts that have to be milled should be designed with economical tolerances that can be achieved in production milling. If the part is designed with tolerances finer than necessary, additional operations will have to be added to achieve these tolerances ——and this will increase the cost of the part.Grinding is one of the most widely used methods of finishing parts to extremely close tolerances and low surface roughness. Currently, there are grinders for almost for almost every type of grinding operation. Particular design features of a part dictate to a large degree the type of grinding machine required. Where processing costs are excessive, parts redesigned to utilize a less expensive, higher output grinding method may be well worthwhile. For example, wherever possible the production economy of center less grinding should be taken advantage of by proper design consideration.Although grinding is usually considered a finishing operation, it is often employed as a complete machining process on work which can be ground down from rough condition without being turned or otherwise machined. Thus many types of forgings and other parts are finished completely with the grinding wheel at appreciable savings of time and expense.Classes of grinding machines include the following: cylindrical grinders, center less grinders, internal grinders, surface grinders, and tool and cutter grinders.The cylindrical and center less grinders are for straight cylindrical or taper work; thus splices, shafts, and similar parts are ground on cylindrical machines either of the common-center type or the center less machine.Thread grinders are used for grinding precision threads for thread gages, and threads on precision where theparts concentricity between the diameter of the shaft and the pitch diameter of the thread must be held to close tolerances.The internal grinders are used for grinding of precision holes, cylinder bores, and similar operations where bores of all kinds are to be finished.The surface grinders are for finishing all kinds of flat work, or work with plain surfaces which may be operated upon either by the edge of a wheel or by the face of a grinding wheel. These machines may have reciprocating or rotating tables.译文：机械设计基础机械设计基础是指机械装置和机械系统——机器、产品、结构、设备和仪器的设计。
农业用机械设备外文文献翻译、中英文翻译、外文翻译
农业用机械设备外文文献翻译、中英文翻译、外文翻译在公元前1世纪，中国已经开始推广使用耧，这是世界上最早的条播机具，在北方旱作区仍然得到应用。
1636年，希腊制造了世界上第一台播种机。
1830年，俄国人在畜力多铧犁上加装播种装置制成了犁播机。
1860年后，英美等国开始大量生产畜力谷物条播机。
20世纪后，牵引和悬挂式谷物条播机以及运用气力排种的播种机相继出现。
50年代，精密播种机开始得到发展。
中国从20世纪50年代开始引进谷物条播机、棉花播种机等。
60年代，中国先后研制成了悬挂式谷物播种机、离心式播种机、通用机架播种机和气吸式播种机等多种类型，并研制成了磨纹式排种器。
到70年代，中国已经形成了播种中耕通用机和谷物联合播种机两个系列，并成功研制出了精密播种机。
播种机具有播种均匀、深浅一致、行距稳定、覆土良好、节省种子、工作效率高等特点。
正确使用播种机应注意以下10个要点：1）在进田作业前，要清理播种箱内的杂物和开沟器上的缠草、泥土，确保状态良好。
对拖拉机及播种机的各传动、转动部位，按照说明书的要求加注润滑油，尤其是每次作业前要注意传动链条润滑和张紧情况以及播种机上螺栓的紧固情况。
2）机架不能倾斜，播种机与拖拉机挂接后，不得倾斜，工作时应使机架前后呈水平状态。
3）搞好各种调整，按照使用说明书的规定和农艺要求，将播种量、开沟器的行距、开沟覆土镇压轮的深浅调整适当。
Seeder Tips1.Pay n to adding good quality seeds to the seed box to XXX。
Make sure there are no small。
broken。
or impure seeds。
Also。
XXX.2.Before large-scale seeding。
conduct a 20-XXX.3.Choose a suitable route for the seeding machine to move ina straight line at a constant speed。
机械专业文献带翻译
机械专业文献带翻译Title: Research and Development of a Novel Mechanical Device for Automated Assembly of Small Parts。
Abstract:The assembly of small parts is a time-consuming and labor-intensive process, often requiring skilled workers to perform the task. In order to improve efficiency and reduce costs, a novel mechanical device for automated assembly of small parts has been developed. This device is capable of handling a variety of small parts with high precision and speed, and can significantly reduce the time and cost required for assembly.Introduction:The assembly of small parts is a critical process in many industries, including electronics, automotive, and medical device manufacturing. This process often requiresskilled workers to perform the task, which can be time-consuming and costly. In addition, human error can lead to defects and quality issues, further increasing costs and reducing efficiency.To address these challenges, a novel mechanical device for automated assembly of small parts has been developed. This device is capable of handling a variety of small parts with high precision and speed, and can significantly reduce the time and cost required for assembly.Design and Development:The mechanical device for automated assembly of small parts consists of several key components, including a feeder, a manipulator, and a control system. The feeder is responsible for delivering small parts to the manipulator, which then assembles the parts according to a predetermined pattern. The control system coordinates the movements of the feeder and manipulator, ensuring that the assembly process is carried out with high precision and speed.The design of the manipulator is particularly important, as it must be capable of handling a wide range of smallparts with varying shapes and sizes. The manipulatorconsists of a series of grippers and suction cups, whichcan be adjusted to accommodate different types of parts.The grippers and suction cups are controlled by a series of motors and sensors, which ensure that the parts are picked up and assembled accurately.Testing and Evaluation:The mechanical device for automated assembly of small parts has been tested extensively in a laboratory setting, and has demonstrated high levels of precision and speed.The device is capable of handling a wide range of small parts, including electronic components, screws, and bolts.In addition, the device has been shown to significantly reduce the time and cost required for assembly, compared to manual assembly methods.Future Directions:The mechanical device for automated assembly of small parts has significant potential for use in a variety of industries, including electronics, automotive, and medical device manufacturing. Further research and development is needed to optimize the design and performance of the device, and to explore its potential for use in new applications.Conclusion:The development of a novel mechanical device for automated assembly of small parts has the potential to revolutionize the assembly process in many industries. This device is capable of handling a wide range of small parts with high precision and speed, and can significantly reduce the time and cost required for assembly. Further research and development is needed to optimize the design and performance of the device, and to explore its potential for use in new applications.。
(完整版)机械类外文文献翻译
文献翻译英文原文：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 are 02h 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 .2cos )2cos(22cos 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]322142322min 2)(cos l l l l l l --+=γ (4) 322142322max 2)(cos l l l l l l +-+=γ (5) max min180γγ-︒=' (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。
机械类英文文献+翻译
机械类英文文献+翻译20.9 MACHINABILITYThe machinability of a material usually defined in terms of four factors:1、Surface finish and integrity of the machined part;2、Tool life obtained;3、Force and power requirements;4、Chip control.Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone.Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below.20.9.1 Machinability Of SteelsBecause steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels.Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in resulfurized steels.Phosphorus in steels has two major effects. It strengthens the ferrite, causingincreased hardness. Harder steels result in better chip formation and surface finish. Note that soft steels can be difficult to machine, with built-up edge formation and poor surface finish. The second effect is that increased hardness causes the formation of short chips instead of continuous stringy ones, thereby improving machinability.Leaded Steels. A high percentage of lead in steels solidifies at the tip of manganese sulfide inclusions. In non-resulfurized grades of steel, lead takes the form of dispersed fine particles. Lead is insoluble in iron, copper, and alumin um and their alloys. Because of its low shear strength, therefore, lead acts as a solid lubricant (Section 32.11) and is smeared over the tool-chip interface du ring cutting. This behavior has been verified by the presence of high concentra tions of lead on the tool-side face of chips when machining leaded steels.When the temperature is sufficiently high-for instance, at high cutting spee ds and feeds (Section 20.6)—the lead melts directly in front of the tool, acting as a liquid lubricant. In addition to this effect, lead lowers the shear stress in the primary shear zone, reducing cutting forces and power consumption. Lead can be used in every grade of steel, such as 10xx, 11xx, 12xx, 41xx, etc. Le aded steels are identified by the letter L between the second and third numeral s (for example, 10L45). (Note that in stainless steels, similar use of the letter L means “low carbon,”a condition that improves their corrosion resistance.)However, because lead is a well-known toxin and a pollutant, there are se rious environmental concerns about its use in steels (estimated at 4500 tons of lead consumption every year in the production of steels). Consequently, there is a continuing trend toward eliminating the use of lead in steels (lead-free ste els). Bismuth and tin are now being investigated as possible substitutes for lea d in steels.Calcium-Deoxidized Steels. An important development is calcium-deoxidize d steels, in which oxide flakes of calcium silicates (CaSo) are formed. These f lakes, in turn, reduce the strength of the secondary shear zone, decreasing tool-chip interface and wear. Temperature is correspondingly reduced. Consequently, these steels produce less crater wear, especially at high cutting speeds.Stainless Steels. Austenitic (300 series) steels are generally difficult to mac hine. Chatter can be s problem, necessitating machine tools with high stiffness. However, ferritic stainless steels (also 300 series) have good machinability. Martensitic (400 series) steels are abrasive, tend to form a built-up edge, and req uire tool materials with high hot hardness and crater-wear resistance. Precipitati on-hardening stainless steels are strong and abrasive, requiring hard and abrasio n-resistant tool materials.The Effects of Other Elements in Steels on Machinability. The presence of aluminum and silicon in steels is always harmful because these elements com bine with oxygen to form aluminum oxide and silicates, which are hard and a brasive. These compounds increase tool wear and reduce machinability. It is es sential to produce and use clean steels.Carbon and manganese have various effects on the machinability of steels, depending on their composition. Plain low-carbon steels (less than 0.15% C) c an produce poor surface finish by forming a built-up edge. Cast steels are mor e abrasive, although their machinability is similar to that of wrought steels. To ol and die steels are very difficult to machine and usually require annealing pr ior to machining. Machinability of most steels is improved by cold working, w hich hardens the material and reduces the tendency for built-up edge formation.Other alloying elements, such as nickel, chromium, molybdenum, and vana dium, which improve the properties of steels, generally reduce machinability. T he effect of boron is negligible. Gaseous elements such as hydrogen and nitrog en can have particularly detrimental effects on the properties of steel. Oxygen has been shown to have a strong effect on the aspect ratio of the manganese sulfide inclusions; the higher the oxygen content, the lower the aspect ratio an d the higher the machinability.In selecting various elements to improve machinability, we should consider the possible detrimental effects of these elements on the properties and strengt h of the machined part in service. At elevated temperatures, for example, lead causes embrittlement of steels (liquid-metal embrittlement, hot shortness; see Se ction 1.4.3), although at room temperature it has no effect on mechanical prop erties.Sulfur can severely reduce the hot workability of steels, because of the fo rmation of iron sulfide, unless sufficient manganese is present to prevent such formation. At room temperature, the mechanical properties of resulfurized steelsdepend on the orientation of the deformed manganese sulfide inclusions (aniso tropy). Rephosphorized steels are significantly less ductile, and are produced so lely to improve machinability.20.9.2 Machinability of Various Other MetalsAluminum is generally very easy to machine, although the softer grades te nd to form a built-up edge, resulting in poor surface finish. High cutting speed s, high rake angles, and high relief angles are recommended. Wrought aluminu m alloys with high silicon content and cast aluminum alloys may be abrasive; they require harder tool materials. Dimensional tolerance control may be a pro blem in machining aluminum, since it has a high thermal coefficient of expans ion and a relatively low elastic modulus.Beryllium is similar to cast irons. Because it is more abrasive and toxic, t hough, it requires machining in a controlled environment.Cast gray irons are generally machinable but are. Free carbides in castings reduce their machinability and cause tool chipping or fracture, necessitating to ols with high toughness. Nodular and malleable irons are machinable with hard tool materials.Cobalt-based alloys are abrasive and highly work-hardening. They require sharp, abrasion-resistant tool materials and low feeds and speeds.Wrought copper can be difficult to machine because of built-up edge form ation, although cast copper alloys are easy to machine. Brasses are easy to ma chine, especially with the addition pf lead (leaded free-machining brass). Bronz es are more difficult to machine than brass.Magnesium is very easy to machine, with good surface finish and prolong ed tool life. However care should be exercised because of its high rate of oxi dation and the danger of fire (the element is pyrophoric).Molybdenum is ductile and work-hardening, so it can produce poor surfac e finish. Sharp tools are necessary.Nickel-based alloys are work-hardening, abrasive, and strong at high tempe ratures. Their machinability is similar to that of stainless steels.Tantalum is very work-hardening, ductile, and soft. It produces a poor surf ace finish; tool wear is high.Titanium and its alloys have poor thermal conductivity (indeed, the lowest of all metals), causing significant temperature rise and built-up edge; they can be difficult to machine.Tungsten is brittle, strong, and very abrasive, so its machinability is low, although it greatly improves at elevated temperatures.Zirconium has good machinability. It requires a coolant-type cutting fluid, however, because of the explosion and fire.20.9.3 Machinability of Various MaterialsGraphite is abrasive; it requires hard, abrasion-resistant, sharp tools.Thermoplastics generally have low thermal conductivity, low elastic modul us, and low softening temperature. Consequently, machining them requires tools with positive rake angles (to reduce cutting forces), large relief angles, small depths of cut and feed, relatively high speeds, and proper support of the work piece. Tools should be sharp.External cooling of the cutting zone may be necessary to keep the chips f rom becoming “gummy”and sticking to the tools. Cooling can usually be achi eved with a jet of air, vapor mist, or water-soluble oils. Residual stresses may develop during machining. To relieve these stresses, machined parts can be an nealed for a period of time at temperatures ranging from to ( to ), and then cooled slowly and uniformly to room temperature.Thermosetting plastics are brittle and sensitive to thermal gradients during cutting. Their machinability is generally similar to that of thermoplastics.Because of the fibers present, reinforced plastics are very abrasive and are difficult to machine. Fiber tearing, pulling, and edge delamination are significa nt problems; they can lead to severe reduction in the load-carrying capacity of the component. Furthermore, machining of these materials requires careful rem oval of machining debris to avoid contact with and inhaling of the fibers.The machinability of ceramics has improved steadily with the development of nanoceramics (Section 8.2.5) and with the selection of appropriate processi ng parameters, such as ductile-regime cutting (Section 22.4.2).Metal-matrix and ceramic-matrix composites can be difficult to machine, d epending on the properties of the individual components, i.e., reinforcing or wh iskers, as well as the matrix material.20.9.4 Thermally Assisted MachiningMetals and alloys that are difficult to machine at room temperature can be machined more easily at elevated temperatures. In thermally assisted machinin g (hot machining), the source of heat—a torch, induction coil, high-energy bea m (such as laser or electron beam), or plasma arc—is forces, (b) increased too l life, (c) use of inexpensive cutting-tool materials, (d) higher material-removal rates, and (e) reduced tendency for vibration and chatter.It may be difficult to heat and maintain a uniform temperature distribution within the workpiece. Also, the original microstructure of the workpiece may be adversely affected by elevated temperatures. Most applications of hot machi ning are in the turning of high-strength metals and alloys, although experiment s are in progress to machine ceramics such as silicon nitride.SUMMARYMachinability is usually defined in terms of surface finish, tool life, force and power requirements, and chip control. Machinability of materials depends n ot only on their intrinsic properties and microstructure, but also on proper sele ction and control of process variables.20.9 可机加工性一种材料的可机加工性通常以四种因素的方式定义：1、分的表面光洁性与表面完整性。
机械类外文文献及翻译
机械类外文文献及翻译(文档含中英文对照即英文原文和中文翻译)原文：GEAR AND SHAFT INTRODUCTIONAbstract:The important position of the wheel gear and shaft can't falter in traditional machine and modern machines.The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box. The passing to process to make them can is divided into many model numbers, using for many situations respectively. So we must be the multilayers to the understanding of the wheel gear and shaft in many ways .Key words: Wheel gear; ShaftIn the force analysis of spur gears, the forces are assumed to act in a single plane. We shall study gears in which the forces have three dimensions. The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. And in the case ofbevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn.Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid.The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement. In spur gears the line of contact is parallel to the axis of the rotation; in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side by side on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft, the hand of the gears should be selected so as to produce the minimum thrust load.Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power. There is on difference between a crossed heli : cal gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand; that is ,a right-hand driver goes with a right-hand driven. In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle areequal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand.Worm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm gear are used to provide a high angular-velocity reduction between nonintersecting shafts which are usually at right angle. The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact. However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed helical gears.Worm gearing are either single or double enveloping. A single-enveloping gearing is onein which the gear wraps around or partially encloses the worm.. A gearing in which each element partially encloses the other is, of course, a double-enveloping worm gearing. The important difference between the two is that area contact exists between the teeth of double-enveloping gears while only line contact between those of single-enveloping gears. The worm and worm gear of a set have the same hand of helix as for crossed helical gears, but the helix angles are usually quite different. The helix angle on the worm is generally quite large, and that on the gear very small. Because of this, it is usual to specify the lead angle on the worm, which is the complement of the worm helix angle, and the helix angle on the gear; the two angles are equal for a 0-deg. Shaft angle.When gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required. Although bevel gear are usually made for a shaft angle of 0 deg. They may be produced for almost any shaft angle. The teeth may be cast, milled, or generated. Only the generated teeth may be classed as accurate. In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing. This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth. Another difficulty, which occurs in predicting the stress in bevel-gear teeth, is the fact the teeth are tapered.Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively. As in the case of squr gears, however, they become noisy at higher values of the pitch-line velocity. In these cases it is often go : od design practice to go to the spiral bevel gear, which is the bevel counterpart of thehelical gear. As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered.It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset. Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution. The tooth action between such gears is a combination of rolling and sliding along a straight line and has much in common with that of worm gears.A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other power-transmission elements. Shaft may be subjected to bending, tension, compression, or torsional loads, acting singly or in combination with one another. When they are combined, one may expect to find both static and fatigue strength to be important design considerations, since a single shaft may be subjected to static stresses, completely reversed, and repeated stresses, all acting at the same time.The word “shaft” covers numerous v ariations, such as axles and spindles. Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load. A shirt rotating shaft is often called a spindle.When either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of deflection before analyzing the stresses. The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe. But by no means should the designer assume that they are safe; it is almost always necessary to calculate them so that he knows they are within acceptable limits. Whenever possible, the power-transmission elements, such as gears or pullets, should be located close to the supporting bearings, This reduces the bending moment, and hence the deflection and bending stress.Although the von Mises-Hencky-Goodman method is difficult to use in design of shaft, it probably comes closest to predicting actual failure. Thus it is a good way of checking a shaft that has already been designed or of discovering why a particular shaft has failed in service. Furthermore, there are a considerable number of shaft-design problems in which the dimension are pretty well limited by other considerations, such as rigidity, and it is only necessary for the designer to discover something about the fillet sizes, heat-treatment,and surface finish and whether or not shot peening is necessary in order to achieve the required life and reliability.Because of the similarity of their functions, clutches and brakes are treated together. In a simplified dynamic representation of a friction clutch, or brake, two in : ertias I and I traveling at the respective angular velocities W and W, one of which may be zero in the case of brake, are to be brought to the same speed by engaging the clutch or brake. Slippage occurs because the two elements are running at different speeds and energy is dissipated during actuation, resulting in a temperature rise. In analyzing the performance of these devices we shall be interested in the actuating force, the torque transmitted, the energy loss and the temperature rise. The torque transmitted is related to the actuating force, the coefficient of friction, and the geometry of the clutch or brake. This is problem in static, which will have to be studied separately for eath geometric configuration. However, temperature rise is related to energy loss and can be studied without regard to the type of brake or clutch because the geometry of interest is the heat-dissipating surfaces. The various types of clutches and brakes may be classified as fllows:. Rim type with internally expanding shoes. Rim type with externally contracting shoes. Band type. Disk or axial type. Cone type. Miscellaneous typeThe analysis of all type of friction clutches and brakes use the same general procedure. The following step are necessary:. Assume or determine the distribution of pressure on the frictional surfaces.. Find a relation between the maximum pressure and the pressure at any point. Apply the condition of statical equilibrium to find (a) the actuating force, (b) the torque, and (c) the support reactions.Miscellaneous clutches include several types, such as the positive-contact clutches, overload-release clutches, overrunning clutches, magnetic fluid clutches, and others.A positive-contact clutch consists of a shift lever and two jaws. The greatest differences between the various types of positive clutches are concerned with the design of the jaws. To provide a longer period of time for shift action during engagement, the jaws may be ratchet-shaped, or gear-tooth-shaped. Sometimes a great many teeth or jaws are used, and they may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of the mating elements.Although positive clutches are not used to the extent of the frictional-contact type, they do have important applications where synchronous operation is required.Devices such as linear drives or motor-operated screw drivers must run to definite limit and then come to a stop. An overload-release type of clutch is required for these applications. These clutches are usually spring-loaded so as to release at a predetermined toque. The clicking sound which is heard when the overload point is reached is considered to be a desirable signal.An overrunning clutch or coupling permits the driven member of a machine to “freewheel” or “overrun” bec ause the driver is stopped or because another source of power increase the speed of the driven. This : type of clutch usually uses rollers or balls mounted between an outer sleeve and an inner member having flats machined around the periphery. Driving action is obtained by wedging the rollers between the sleeve and the flats. The clutch is therefore equivalent to a pawl and ratchet with an infinite number of teeth.Magnetic fluid clutch or brake is a relatively new development which has two parallel magnetic plates. Between these plates is a lubricated magnetic powder mixture. An electromagnetic coil is inserted somewhere in the magnetic circuit. By varying the excitation to this coil, the shearing strength of the magnetic fluid mixture may be accurately controlled. Thus any condition from a full slip to a frozen lockup may be obtained.齿轮和轴的介绍摘要:在传统机械和现代机械中齿轮和轴的重要地位是不可动摇的。
机械类外文文献翻译(中英文翻译)
机械类外文文献翻译(中英文翻译)英文原文Mechanical Design and Manufacturing ProcessesMechanical design is the application of science and technology to devise new or improved products for the purpose of satisfying human needs. It is a vast field of engineering technology which not only concerns itself with the original conception of the product in terms of its size, shape and construction details, but also considers the various factors involved in the manufacture, marketing and use of the product.People who perform the various functions of mechanical design are typically called designers, or design engineers. Mechanical design is basically a creative activity. However, in addition to being innovative, a design engineer must also have a solid background in the areas of mechanical drawing, kinematics, dynamics, materials engineering, strength of materials and manufacturing processes.As stated previously, the purpose of mechanical design is to produce a product which will serve a need for man. Inventions, discoveries and scientific knowledge by themselves do not necessarily benefit people; only if they are incorporated into a designed product will a benefit be derived. It should be recognized, therefore, that a human need must be identified before a particular product is designed.Mechanical design should be considered to be an opportunity to use innovative talents to envision a design of a product, to analyze the systemand then make sound judgments on how the product is to be manufactured. It is important to understand the fundamentals of engineering rather than memorize mere facts and equations. There are no facts or equations which alone can be used to provide all the correct decisions required to produce a good design.On the other hand, any calculations made must be done with the utmost care and precision. For example, if a decimal point is misplaced, an otherwise acceptable design may not function.Good designs require trying new ideas and being willing to take a certain amount of risk, knowing that if the new idea does not work the existing method can be reinstated. Thus a designer must have patience, since there is no assurance of success for the time and effort expended. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated.New designs generally have "bugs" or unforeseen problems which must be worked out before the superior characteristics of the new designs can be enjoyed. Thus there is a chance for a superior product, but only at higher risk. It should be emphasized that, if a design does not warrant radical new methods, such methods should not be applied merely for the sake of change.During the beginning stages of design, creativity should be allowedto flourish without a great number of constraints. Even though many impractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which is ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise.Psychologists frequently talk about trying to fit people to the machines they operate. It is essentially the responsibility of the design engineer to strive to fit machines to people. This is not an easy task, since there is really no average person for which certain operating dimensions and procedures are optimum.Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to administrative, management, or supervisory persons, is attempting to sell or to prove to them that this solution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted.Basically, there are only three means of communication available tous. These are the written, the oral, and the graphical forms. Therefore the successful engineer will be technically competent and versatile in all three forms of communication. A technically competent person who lacks ability in any one of these forms is severely handicapped. If ability in all three forms is lacking, no one will ever know how competent that person is!The competent engineer should not be afraid of the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea. There is a great deal to be learned from a failure, and the greatest gains are obtained by those willing to risk defeat. In the final analysis, the real failure would lie in deciding not to make the presentation at all. To communicate effectively, the following questions must be answered:(1) Does the design really serve a human need?(2) Will it be competitive with existing products of rival companies?(3) Is it economical to produce?(4) Can it be readily maintained?(5) Will it sell and make a profit?Only time will provide the true answers to the preceding questions, but the product should be designed, manufactured and marketed only with initial affirmative answers. The design engineer also must communicate the finalized design to manufacturing through the use of detail and assembly drawings.Quite often, a problem will occur during the manufacturing cycle [3].It may be that a change is required in the dimensioning or tolerancing of a part so that it can be more readily produced. This fails in the category of engineering changes which must be approved by the design engineer so that the product function will not be adversely affected. In other cases, a deficiency in the design may appear during assembly or testing just prior to shipping. These realities simply bear out the fact that design is a living process. There is always a better way to do it and the designer should constantly strive towards finding that better way.Designing starts with a need, real or imagined. Existing apparatus may need improvements in durability, efficiently, weight, speed, or cost. New apparatus may be needed to perform a function previously done by men, such as computation, assembly, or servicing. With the objective wholly or partly defined, the next step in design is the conception of mechanisms and their arrangements that will perform the needed functions.For this, freehand sketching is of great value, not only as a record of one's thoughts and as an aid in discussion with others, but particularly for communication with one's own mind, as a stimulant for creative ideas.When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive east. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strength of the several components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles ofmechanics, such as those of statics for reaction forces and for the optimumutilization of friction; of dynamics for inertia, acceleration, and energy; of elasticity and strength of materials for stress。
机床——机械类外文文献翻译、中英文翻译
毕业设计(论文)外文资料翻译系部：专业：姓名：学号：外文出处：English For Electromechanical(用外文写)Engineering附件：1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文机床机床是用于切削金属的机器。
工业上使用的机床要数车床、钻床和铣床最为重要。
其它类型的金属切削机床在金属切削加工方面不及这三种机床应用广泛。
车床通常被称为所有类型机床的始祖。
为了进行车削，当工件旋转经过刀具时，车床用一把单刃刀具切除金属。
用车削可以加工各种圆柱型的工件，如：轴、齿轮坯、皮带轮和丝杠轴。
镗削加工可以用来扩大和精加工定位精度很高的孔。
钻削是由旋转的钻头完成的。
大多数金属的钻削由麻花钻来完成。
用来进行钻削加工的机床称为钻床。
铰孔和攻螺纹也归类为钻削过程。
铰孔是从已经钻好的孔上再切除少量的金属。
攻螺纹是在内孔上加工出螺纹，以使螺钉或螺栓旋进孔内。
铣削由旋转的、多切削刃的铣刀来完成。
铣刀有多种类型和尺寸。
有些铣刀只有两个切削刃，而有些则有多达三十或更多的切削刃。
铣刀根据使用的刀具不同能加工平面、斜面、沟槽、齿轮轮齿和其它外形轮廓。
牛头刨床和龙门刨床用单刃刀具来加工平面。
用牛头刨床进行加工时，刀具在机床上往复运动，而工件朝向刀具自动进给。
在用龙门刨床进行加工时，工件安装在工作台上，工作台往复经过刀具而切除金属。
工作台每完成一个行程刀具自动向工件进给一个小的进给量。
磨削利用磨粒来完成切削工作。
根据加工要求，磨削可分为精密磨削和非精密磨削。
精密磨削用于公差小和非常光洁的表面，非精密磨削用于在精度要求不高的地方切除多余的金属。
车床车床是用来从圆形工件表面切除金属的机床，工件安装在车床的两个顶尖之间，并绕顶尖轴线旋转。
车削工件时，车刀沿着工件的旋转轴线平行移动或与工件的旋转轴线成一斜角移动，将工件表面的金属切除。
车刀的这种位移称为进给。
车刀装夹在刀架上，刀架则固定在溜板上。
溜板是使刀具沿所需方向进行进给的机构。
机械原理外文文献
机械原理外文文献IntroductionMechanical principles are fundamental concepts in engineering and physics that are essential for understanding the behavior and operation of machines and mechanical systems. These principles are the building blocks of mechanical engineering and are used to design, analyze, and optimize mechanical devices and systems. In this paper, we will discuss some of the key mechanical principles, including force, motion, energy, and momentum, and their applications in various mechanical systems.Force and MotionForce and motion are two of the most fundamental concepts in mechanical engineering. Force is defined as any interaction that causes an object to undergo a change in speed, direction, or shape. In mechanical systems, forces are applied to machines and mechanical components to produce motion or to resist motion. The study of forces and their effects on motion is known as dynamics, and it is essential for understanding the behavior of mechanical systems.One of the key laws of motion is Newton's first law, which states that an object at rest will remain at rest, and an object in motion will remain in motion, unless acted upon by an external force. This law is used to analyze the behavior of mechanical systems and to design machines that can produce or resist motion.Energy and WorkEnergy is another critical concept in mechanical engineering and is defined as the ability to do work. Work, in the context of mechanical systems, is the transfer of energy from one object to another through the application of a force over a distance. The study of energy and work is essential for designing and analyzing mechanical systems that involve the conversion and transfer of energy, such as engines, turbines, and pumps.One of the fundamental principles of energy is the conservation of energy, which states that the total energy in a closed system remains constant over time. This principle is used to analyze the behavior of mechanical systems and to design machines that can efficiently convert and transfer energy.Momentum and ImpulseMomentum is a measure of an object's motion and is defined as the product of its mass and velocity. In mechanical systems, momentum is essential for understanding the behavior of moving objects and for designing machines that can produce or resist motion. Impulse is the change in momentum of an object due to the application of a force over a period of time, and it is used to analyze the behavior of mechanical systems during collisions and other dynamic events.One of the key principles of momentum and impulse is the conservation of momentum, which states that the total momentum in a closed system remains constant over time. This principle is used to analyze the behavior of mechanical systems during collisions and to design machines that can efficiently transfer momentum.ApplicationsThe principles of force, motion, energy, and momentum are used in a wide range of mechanical systems and devices. For example, in the design of engines and turbines, the principles of energy and work are used to optimize the conversion of energy from one form to another. In the design of vehicles and transportation systems, the principles of force and motion are used to analyze the behavior of moving objects and to optimize the performance of mechanical components. In the design of robotics and automation systems, the principles of force, motion, energy, and momentum are used to optimize the operation of mechanical devices and to ensure the safety and reliability of the systems.ConclusionMechanical principles are essential for understanding the behavior and operation of machines and mechanical systems. The concepts of force, motion, energy, and momentum are fundamental to the design, analysis, and optimization of mechanical devices and systems. These principles are used in a wide range of applications, from engines and turbines to vehicles and transportation systems, to robotics and automation systems. By understanding and applying these principles, engineers can design machines that are efficient, reliable, and safe, and that can meet the demands of modern industry and technology.Overall, the principles of force, motion, energy, and momentum are the foundation of mechanical engineering and are essential for the development of new technologies and innovations in the field.。
机械外文参考文献
机械外文参考文献深度学习在机械领域的应用越来越广泛。
本文综述了机械外文参考文献中关于深度学习在机械中的应用研究。
1. Zhang, K., & Kang, L. (2018). Deep learning for inspection and intelligent manufacturing: An overview. Advanced Engineering Informatics, 38, 598-610.这篇综述文章系统地介绍了深度学习在机械检测和智能制造中的应用。
作者回顾了深度学习的发展历程，并探讨了其在工业制造中的潜力和挑战。
2. Chen, D., & Hu, B. (2019). Deep learning for fault diagnosis of rotating machinery: A review. Mechanical Systems and Signal Processing, 107, 49-67.作者对深度学习在旋转机械故障诊断方面的研究进行了综述。
文章介绍了目前广泛应用的深度学习算法，并提供了用于故障诊断的数据集和评估方法。
3. Li, K., et al. (2020). Deep learning-based approachfor intelligent monitoring and prognostics in machining processes. Journal of Manufacturing Systems, 56, 333-345.这篇文章介绍了基于深度学习的智能监测和预测在机械加工过程中的应用。
作者提出了一种新的深度学习框架，用于实时监测和预测机械加工过程中的关键指标。
4. Wang, S., et al. (2017). Machine vision based on deep learning for surface quality inspection in manufacturing processes. Robotics and Computer-Integrated Manufacturing, 46, 151-160.该文介绍了基于深度学习的机器视觉在制造过程中表面质量检测方面的应用。
机械类研究报告外文
机械类研究报告外文A Study on Mechanical ScienceAbstract:Mechanical science is a branch of science and engineering that deals with the design, construction, and use of machines. This study aims to analyze the current state of mechanical science and its future prospects. The study mainly investigates the history, principles, and applications of mechanical science. It also examines the advancements made in this field, as well as the challenges faced by researchers. The findings suggest that mechanical science has made significant contributions to various industries and has the potential for further developments in the future.1. Introduction:Mechanical science is a multidisciplinary field that combines knowledge from physics, mathematics, and engineering. It encompasses the study of mechanics, kinematics, thermodynamics, and materials science. The development of mechanical science has been driven by the need to improve the efficiency, safety, and performance of machines.2. History of Mechanical Science:The origins of mechanical science can be traced back to ancient civilizations such as the Greeks and Romans, who developed early mechanical devices. However, it was during the Industrial Revolution in the 18th century that mechanical science gained significant attention. The development of steam engines and other machines marked a turning point in the history of mechanicalscience.3. Principles of Mechanical Science:Mechanical science is based on several fundamental principles, including Newton's laws of motion, conservation of energy, and the properties of materials. These principles form the basis for the analysis and design of mechanical systems. Understanding these principles is crucial for developing innovative and efficient machines.4. Applications of Mechanical Science:Mechanical science has a wide range of applications in various sectors, including transportation, manufacturing, and energy production. For example, the automotive industry relies on mechanical science to design and manufacture vehicles. The aerospace industry uses mechanical science to develop aircraft and spacecraft. Mechanical science is also used in the energy sector to design and maintain power plants.5. Advancements in Mechanical Science:In recent years, there have been significant advancements in mechanical science. The development of computer-aided design (CAD) and computer-aided manufacturing (CAM) systems has revolutionized the design and production processes. Additive manufacturing techniques, such as 3D printing, have also opened up new possibilities in the field. Furthermore, there have been advancements in materials science that have led to the development of stronger and lighter materials.6. Challenges in Mechanical Science:Despite the advancements made, there are challenges that researchers face in the field of mechanical science. One of the challenges is the demand for sustainable and environmentally-friendly technologies. There is also a need for continuous innovation to meet the changing market demands. Additionally, the field faces challenges in terms of optimizing the performance and efficiency of machines.7. Conclusion:In conclusion, mechanical science plays a crucial role in the design, construction, and use of machines. It has a wide range of applications and has made significant contributions to various industries. With the advancements in technology and the constant demand for more efficient machines, mechanical science has the potential for further developments in the future. However, researchers need to address the challenges faced in order to harness the full potential of this field.。
机械类毕业设计英文文献
Introduciton of MachiningHave a shape as a processing method, all machining process for the production of the most commonly used and most important method. Machining process is a process generated shape, in this process, Drivers device on the workpiece material to be in the form of chip removal. Although in some occasions, the workpiece under no circumstances, the use of mobile equipment to the processing, However, the majority of the machining is not only supporting the workpiece also supporting tools and equipment to complete. Machining know the process has two aspects. Small group of low-cost production. For casting, forging and machining pressure, every production of a specific shape of the workpiece, even a spare parts, almost have to spend the high cost of processing. Welding to rely on the shape of the structure, to a large extent, depend on effective in the form of raw materials. In general, through the use of expensive equipment and without special processing conditions, can be almost any type of raw materials, mechanical processing to convert the raw materials processed into the arbitrary shape of the structure, as long as the external dimensions large enough, it is possible. Because of a production of spare parts, even when the parts and prefer machining.Strict precision and good surface finish, Machining the second purpose is the establishment of the high precision and surface finish possible on the basis of. Many parts, if any other means of production belonging to the large-scale production, Well Machining is a low-tolerance and can meet the requirements of small batch production. Besides, many parts on the production and processing of coarse process to improve its general shape of the surface. It is only necessary precision and choose only the surface machining. For instance, thread, in addition to mechanical processing, almost no other processing method for processing. Another example is the blacksmith pieces keyhole processing, as well as training to be conducted immediately after the mechanical completion of the processing.Primary Cutting Parameters：Cutting the work piece and tool based on the basic relationship between the following four elements to fully describe : the tool geometry, cutting speed, feed rate, depth and penetration of a cutting tool.Cutting Tools must be of a suitable material to manufacture, it must be strong, tough, hard and wear-resistant. Tool geometry -- to the tip plane and cutter angle characteristics -- for each cutting process must be correct.Cutting speed is the cutting edge of work piece surface rate, it is inches per minute to show. In order to effectively processing, and cutting speed must adapt to the level of specific parts -- with knives. Generally, the more hard work piece material, the lower the rate.Progressive Tool to speed is cut into the work piece speed. If the work piece or tool for rotating movement, feed rate per round over the number of inches to the measurement. When the work piece or tool for reciprocating movement and feed rate on each trip through the measurement of inches. Generally, in other conditions, feed rate and cutting speed is inversely proportional to.Depth of penetration of a cutting tool -- to inches dollars -- is the tool to the work piece distance. Rotary cutting it to the chip or equal to the width of the linear cutting chipthickness. Rough than finishing, deeper penetration of a cutting tool depth.Wears of Cutting ToolWe already have been processed and the rattle of the countless cracks edge tool, we learn that tool wear are basically three forms : flank wear, the former flank wear and V-Notch wear. Flank wear occurred in both the main blade occurred vice blade. On the main blade, shoulder removed because most metal chip mandate, which resulted in an increase cutting force and cutting no longer exist. Vice-bladed on, it is determined work piece dimensions and surface finish. Flank wear size of the possible failure of the product and surface finish are also inferior. In most actual cutting conditions, as the principal in the former first deputy flank before flank wear, wear arrival enough, Tool will be effective, the results are made unqualified parts.As Tool stress on the surface uneven, chip and flank before sliding contact zone between stress, in sliding contact the start of the largest, and in contact with the tail of zero, so abrasive wear in the region occurred. This is because the card cutting edge than the nearby settlements near the more serious wear, and bladed chip due to the vicinity of the former flank and lost contact wear lighter. This results from a certain distance from the cutting edge of the surface formed before the knife point Ma pit, which is usually considered before wear. Under normal circumstances, this is wear cross-sectional shape of an arc. In many instances and for the actual cutting conditions, the former flank wear compared to flank wear light, Therefore flank wear more generally as a tool failure of scale signs. But because many authors have said in the cutting speed of the increase, Maeto surface temperature than the knife surface temperatures have risen faster. but because any form of wear rate is essentially temperature changes by the significant impact. Therefore, the former usually wear in high-speed cutting happen.The main tool flank wear the tail is not processed with the work piece surface in contact, Therefore flank wear than wear along with the ends more visible, which is the most common. This is because the local effect, which is as rough on the surface has hardened layer, This effect is by cutting in front of the hardening of the work piece. Not just cutting, and as oxidation skin, the blade local high temperature will also cause this effect. This partial wear normally referred to as pit sexual wear, but occasionally it is very serious. Despite the emergence of the pits on the Cutting Tool nature is not meaningful impact, but often pits gradually become darker If cutting continued the case, then there cutter fracture crisis.If any form of sexual allowed to wear, eventually wear rate increase obviously will be a tool to destroy failure destruction, that will no longer tool for cutting, cause the work piece scrapped, it is good, can cause serious damage machine. For various carbide cutting tools and for the various types of wear, in the event of a serious lapse, on the tool that has reached the end of the life cycle. But for various high-speed steel cutting tools and wear belonging to the non-uniformity of wear, has been found : When the wear and even to allow for a serious lapse, the most meaningful is that the tool can remill use, of course, In practice, cutting the time to use than the short time lapse. Several phenomena are one tool serious lapse began features : the most common is the sudden increase cutting force, appeared on the work piece burning ring patterns and an increase in noise.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary deformation zones and this results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and cutting temperatures will reduce. When considering increase in undeformed chip thickness and cutting speed the situation is more comples. changes in cutting temperature tend to be small. Increase in cutting speed, however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip in primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate, it is appropriate to indicate how cutting temperatures can be assessed from cutting data.The most direct and accurate method for measuring temperatures in high-speed-steel cutting tools is that of Wright&Trent which also yields detailed information on temperature distributions in high-speed-steel tools which relates microstructural changes to thermal history.Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructural changes srising from over tempering of the tempered martensitic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed-steel single point turning tools and twist drills.Automatic Fixture Design：Assembly equipment used in the traditional synchronous fixture put parts of the fixture mobile center, to ensure that components from transmission from the plane or equipment plate placed after removal has been scheduled for position. However, in certain applications, mobile mandatory parts of the center line, it may cause parts or equipment damage. When parts vulnerability and may lead to a small vibration abandoned, or when their location is by machine spindle or specific to die, Tolerance again or when the request is a sophisticated, it would rather let the fixture to adapt to the location of parts, and not the contrary. Fixture because of the interaction and synchro nization devices is independent,The synchronous device can use sophisticated equipment to replace the slip without affecting the fixture force. Fixture specification range from 0.2 inches itinerary, 5 pounds clamping force of the six-inch trip, 400-inch clamping force.The characteristics of modern production is becoming smaller and smaller quantities and product specifications biggest changes. Therefore, in the final stages of production, assembly of production, quantity and product design changes appear to be particularly vulnerable. This situation is forcing many companies to make greater efforts to rationalize the extensive reform and the previously mentioned case of assembly automation. Despite flexible fixture behind the rapid development of flexible transport and handling devices, such as backward in the development of industrial robots, it is still expected to increase the flexibility fixture. In fact the important fixture devices -- the production of the devices to strengthen investment on the fixture so that more flexibility in economic support holders. According to their flexibility and fixture can be divided into : special fixture, the fixture combinations, the standard fixture, high flexible fixture. Flexible fixture on different parts of their high adaptability and the few low-cost replacement for the characteristic.Forms can transform the structure of the flexible fixture can be installed with the change of structure components (such as needle cheek plate, Multi-chip components and flake cheek plate), a non-standard work piece gripper or clamping elements (for example : commencement standard with a clamping fixture and mobile components fixture supporting documents), and working characteristics to determine the work piece fixture in the required position, then need to select some stability flat combination, These constitute a stable plane was fixed in the work piece fixture set position on the clamp-profile structure, all balanced and torque, it has also ensured that the work features close to the work piece. Finally, it must be calculated and adjusted, assembly or disassembly be standard fixture components required for the position, so that the work piece firmly by clamping fixture in China. In accordance with this procedure, the outline fixture structure and equipped with the planning and recording process can be automated control. Structural modeling task is to produce some stable flat combination, Thus, these plane of the work pieces clamping force and will fixture stability. According to usual practice, this task can be human-machine dialogue that is almost completely automated way to completion. A man-machine dialogue that is automated fixture structure modeling to determine the merits can be conducted in an organized and planning fixture design, reduce the amount of the design, shortening the study period and better distribution of work conditions. In short, can be successfully achieved significantly improve fixture efficiency and effectiveness Fully prepared to structure programs and the number of material circumstances, the completion of the first successful assembly can save up to 60% of the time.Therefore fixture process modeling agencies is the purpose of the program have appropriate documents.Fixture design as a complex fixture is not required, only requires a simple positioning, clamping mechanism on it. The design principle is also the same with the universal milling machine fixture, combined with the characteristics of CNC milling, here only offer a fewbasic requirements: 1) to maintain part orientation and installation of the machine coordinate system and the way the consistency of the code coordinate system, the fixture should be able to guarantee installed on the machine to achieve directional(1) the basic requirements of the fixtureIn fact when the CNC milling - as the fixture does not require very complicated and only requires simple positioning, clamping mechanism on it. The design principle is also the same with the universal milling machine fixture, combined with the characteristics of CNC milling, here only offer a few basic requirements:1) to maintain part orientation and the installation process the machine coordinate system and the consistency of the code coordinate system, fixtures should be directed to ensure realization of the machine installation, also asked to coordinate the positioning surface and the machine parts to maintain a certain coordinate between the size of contact.2) To maintain all parts in this process needs to be done face to be processed fully exposed, clamps open to do as much as possible, so clamping components and machined surface should be maintained between a safe distance, and to ask clamping mechanical components can be low is low, to prevent the fixture with the milling machine spindle sleeve or pocket, cutting in the process of collision.3) The fixture is better rigidity and stability. Try not to use change in the process design of the clamping point, when the change in the process have to clamping point can not, be especially careful not to damage the replacement of the clamping point of the fixture or the workpiece location accuracy.(2) Common fixture typesCNC milling fixture less commonly used are the following:1) Universal modular fixture for small batch production or development time, the small parts on the CNC milling machine milling.2) special milling fixture is designed specifically for a particular piece or a similar number of fixture design and manufacture, production or development in general can not be used when you have to.3) multi-station fixture clamping multiple workpieces simultaneously can reduce the number of tool changes, but also easy side processing, side loading and unloading the workpiece, is conducive to shorten the preparation time, increase productivity, more suitable for the production.4) pneumatic or hydraulic fixtures for the production of large quantities, the use of other fixtures and particularly of work, labor-intensive parts. Can reduce labor intensity and increase work productivity, but such fixture structure is more complex and often higher cost, and manufacturing cycle longer.5) The vacuum fixture for positioning a large surface can be sealed or have a larger area of the workpiece. Some CNC milling machine (milling machine, such as siding) with a common vacuum platform itself, the installation part, the rules on the shape of a rectangular blank, directly with a special rubber strip (a certain size requirements of hollow or solid circular cross-section) embedded in fixture sealed tank, and then put a blank, start the pump, you can rough clamping. Of irregularly shaped rough, with the rubber is not used to be putty in their surrounding cast (used rubber cement) seals, this is not onlycumbersome and seizing a long time and low efficiency. To overcome this difficulty, you can use a special vacuum platform transition, superimposed on the general vacuum of its platform.In addition to the several fixtures, the CNC milling process is also often used vise, dividing head and jaw chuck, and other common fixture.(3) the principles of CNC milling fixture selectionIn the selection of fixtures, it is usually necessary to consider the production volume, production efficiency, quality assurance and economy, etc., when used with reference to the following principles:1) In the production of small or developing, should be widely used universal modular fixture, can not be solved only in the combination of workpiece clamping fixture could only give up;2) small batch or batch production of special fixtures can be considered, but should be as simple as possible;3) in the production of large quantities may consider the multi-station fixture and air; hydraulic fixture.。
机械类外文文献及翻译大全
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附：外文翻译外文原文：Fundamentals of Mechanical Design Mechanical design means the design of things and systems of a mechanical nature—machines, products, structures, devices, and instruments. For the most part mechanical design utilizes mathematics, the materials sciences, and the engineering-mechanics sciences.The total design process is of interest to us. How does it begin? Does the engineer simply sit down at his desk with a blank sheet of paper? And, as he jots down some ideas, what happens next? What factors influence or control the decisions which have to be made? Finally, then, how does this design process end?Sometimes, but not always, design begins when an engineer recognizes a need and decides to do something about it. Recognition of the need and phrasing it in so many words often constitute a highly creative act because the need may be only a vague discontent, a feeling of uneasiness, of a sensing that something is not right.The need is usually not evident at all. For example, the need to do something about a food-packaging machine may be indicated by the noise level, by the variations in package weight, and by slight but perceptible variations in the quality of the packaging or wrap.There is a distinct difference between the statement of the need and the identification of the problem. Which follows this statement? The problem is more specific. If the need is for cleaner air, the problem might be that of reducing the dust discharge from power-plant stacks, or reducing the quantity of irritants from automotive exhausts.Definition of the problem must include all the specifications for the thing that is to be designed. The specifications are the input and output quantities, the characteristics of the space the thing must occupy and all the limitations on these quantities. We can regard the thing to be designed as something in a black box. In this case we must specify the inputs and outputs of the box together with their characteristics and limitations. The specifications define the cost, the number to be manufactured, the expected life, the range, the operating temperature, and the reliability.There are many implied specifications which result either from the designer's particular environment or from the nature of the problem itself. The manufacturing processes which are available, together with the facilities of a certain plant, constitute restrictions on a designer's freedom, and hence are a part of the implied specifications. A small plant, for instance, may not own cold-working machinery. Knowing this, the designer selects other metal-processing methods which can be performed in the plant. The labor skills available and the competitive situation also constitute implied specifications.After the problem has been defined and a set of written and implied specifications has been obtained, the next step in design is the synthesis of an optimum solution. Now synthesis cannot take place without both analysis and optimization because the system under design must be analyzed to determine whether the performance complies with the specifications.The design is an iterative process in which we proceed through several steps, evaluate the results, and then return to an earlier phase of the procedure. Thus we may synthesize several components of a system, analyze and optimize them, and return to synthesis to see what effect this has on the remaining parts of the system. Both analysis and optimization require that we construct or devise abstract models of the system which will admit some form of mathematical analysis. We call these modelsmathematical models. In creating them it is our hope that we can find one which will simulate the real physical system very well.Evaluation is a significant phase of the total design process. Evaluation is the final proof of a successful design, which usually involves the testing of a prototype in the laboratory. Here we wish to discover if the design really satisfies the need or needs. Is it reliable? Will it compete successfully with similar products? Is it economical to manufacture and to use? Is it easily maintained and adjusted? Can a profit be made from its sale or use?Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to administrative, management, or supervisory persons, is attempting to sell or to prove to them that this solution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted.Basically, there are only three means of communication available to us. There are the written, the oral, and the graphical forms. Therefore the successful engineer will be technically competent and versatile in all three forms of communication. A technically competent person who lacks ability in any one of these forms is severely handicapped. If ability in all three forms is lacking, no one will ever know how competent that person is!The competent engineer should not be afraid of the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea. There is a great to be learned from a failure, and the greatest gains are obtained by those willing to risk defeat. In the find analysis, the real failure would lie in deciding not to make the presentation at all.Introduction to Machine DesignMachine design is the application of science and technology to devise new or improved products for the purpose of satisfying human needs. It is a vast field of engineering technology which not only concerns itself with the original conception of the product in terms of its size, shape and construction details, but also considers the various factors involved in the manufacture, marketing and use of the product.People who perform the various functions of machine design are typically called designers, or design engineers. Machine design is basically a creative activity. However, in addition to being innovative, a design engineer must also have a solid background in the areas of mechanical drawing, kinematics, dynamics, materials engineering, strength of materials and manufacturing processes.As stated previously, the purpose of machine design is to produce a product which will serve a need for man. Inventions, discoveries and scientific knowledge by themselves do not necessarily benefit people; only if they are incorporated into a designed product will a benefit be derived. It should be recognized, therefore, that a human need must be identified before a particular product is designed.Machine design should be considered to be an opportunity to use innovative talents to envision a design of a product is to be manufactured. It is important to understand the fundamentals of engineering rather than memorize mere facts and equations. There are no facts or equations which alone can be used to provide all the correct decisions to produce a good design. On the other hand, any calculations made must be done with the utmost care and precision. For example, if a decimal point is misplaced,an otherwise acceptable design may not function.Good designs require trying new ideas and being willing to take a certain amount of risk, knowing that is the new idea does not work the existing method can be reinstated. Thus a designer must have patience, since there is no assurance of success for the time and effort expended. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated.New designs generally have “bugs” or unforeseen problems which must be worked out before the superior characteristics of the new designs can be enjoyed. Thus there is a chance for a superior product, but only at higher risk. It should be emphasized that if a design does not warrant radical new methods, such methods should not be applied merely for the sake of change.During the beginning stages of design, creativity should be allowed to flourish without a great number of constraints. Even though many impractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise.Psychologists frequently talk about trying to fit people to the machines they operate. It is essentially the responsibility of the design engineer to strive to fit machines to people. This is not an easy task, since there is really no average person for which certain operating dimensions and procedures are optimum.Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Initially the designer must communicate a preliminary design to get management approval. This is usually done by verbal discussions in conjunction with drawing layouts and written material. To communicate effectively, the following questions must be answered:(1)Does the design really serve a human need?(2)Will it be competitive with existing products of rival companies?(3)Is it economical to produce?(4)Can it be readily maintained?(5)Will it sell and make a profit?Only time will provide the true answers to the preceding questions, but the product should be designed, manufactured and marketed only with initial affirmative answers. The design engineer also must communicate the finalized design to manufacturing through the use of detail and assembly drawings.Quite often, a problem well occur during the manufacturing cycle. It may be that a change is required in the dimensioning or telegramming of a part so that it can be more readily produced. This falls in the category of engineering changes which must be approved by the design engineer so that the product function will not be adversely affected. In other cases, a deficiency in the design may appear during assembly or testing just prior to shipping. These realities simply bear out the fact that design is a living process. There is always a better way to do it and the designer should constantly strive towards finding that better way.MachiningTurning The 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 and accuracy, are now at the designer's fingertips with production speeds 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, in terms of ability to repeat accurately and rapidly. Applying 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 turret 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 to set up on the turret lathe than on the automatic screw machine. Quantities less than 1000 parts may be more economical to set up on the turret lathe 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 upon material turned, tooling, and fees and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.Is some case, 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.Milling With the exceptions of turning and drilling, milling is undoubtedly the most widely used method of removing metal. Well suited and readily adapted to the economical production of any quantity of parts, the almost unlimited versatility of the milling process merits the attention and consideration of designers seriously concerned with the manufacture of their product.As in any other process, parts that have to be milled should be designed with economical tolerances that can be achieved in production milling. If the part is designed with tolerances finer than necessary, additional operations will have to be added to achieve these tolerances——and this will increase the cost of the part.Grinding is one of the most widely used methods of finishing parts to extremely close tolerances and low surfaceroughness. Currently, there are grinders for almost for almost every type of grinding operation. Particular design features of a part dictate to a large degree the type of grinding machine required. Where processing costs are excessive, parts redesigned to utilize a less expensive, higher output grinding method may be well worthwhile. For example, wherever possible the production economy of center less grinding should be taken advantage of by proper design consideration.Although grinding is usually considered a finishing operation, it is often employed as a complete machining process on work which can be ground down from rough condition without being turned or otherwise machined. Thus many types of forgings and other parts are finished completely with the grinding wheel at appreciable savings of time and expense.Classes of grinding machines include the following: cylindrical grinders, center less grinders, internal grinders, surface grinders, and tool and cutter grinders.The cylindrical and center less grinders are for straight cylindrical or taper work; thus splices, shafts, and similar parts are ground on cylindrical machines either of the common-center type or the center less machine.Thread grinders are used for grinding precision threads for thread gages, and threads on precision parts where the concentricity between the diameter of the shaft and the pitch diameter of the thread must be held to close tolerances.The internal grinders are used for grinding of precision holes, cylinder bores, and similar operations where bores of all kinds are to be finished.The surface grinders are for finishing all kinds of flat work, or work with plain surfaces which may be operated upon either by the edge of a wheel or by the face of a grinding wheel. These machines may have reciprocating or rotating tables.译文：机械设计基础机械设计基础是指机械装置和机械系统——机器、产品、结构、设备和仪器的设计。