滚齿机传动设计与滚刀调整毕业论文 外文翻译
毕业设计论文外文文献翻译机械设计制造及其自动化轴承的摩擦与润滑中英文对照
Friction , Lubrication of BearingIn many of the problem thus far , the student has been asked to disregard or neglect friction . A ctually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement.Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary.The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. A lso , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt.There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding,and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. T o produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement .Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. A s shown in figure ,starting friction is always greater than sliding friction .Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction.The friction caused by the wedging action of surface irregularities can be overcome partly by the precision machining of the surfaces. However, even these smooth surfaces may require the use of a substance between them to reduce the friction still more. This substance is usually a lubricant which provides a fine, thin oil film. The film keeps the surfaces apart and prevents the cohesive forces of the surfaces from coming in close contact and producing heat .Another way to reduce friction is to use different materials for the bearing surfaces and rotating parts. This explains why bronze bearings, soft alloy s, and copper and tin iolite bearings are used with both soft andhardened steel shaft. The iolite bearing is porous. Thus, when the bearing is dipped in oil, capillary action carries the oil through the spaces of the bearing. This type of bearing carries its own lubricant to the points where the pressures are the greatest.Moving parts are lubricated to reduce friction, wear, and heat. The most commonly used lubricants are oils, greases, and graphite compounds. Each lubricant serves a different purpose. The conditions under which two moving surfaces are to work determine the type of lubricant to be used and the system selected for distributing the lubricant.On slow moving parts with a minimum of pressure, an oil groove is usually sufficient to distribute the required quantity of lubricant to the surfaces moving on each other .A second common method of lubrication is the splash system in which parts moving in a reservoir of lubricant pick up sufficient oil which is then distributed to all moving parts during each cycle. This system is used in the crankcase of lawn-mower engines to lubricate the crankshaft, connecting rod ,and parts of the piston.A lubrication system commonly used in industrial plants is the pressure system. In this system, a pump on a machine carries the lubricant to all of the bearing surfaces at a constant rate and quantity.There are numerous other sy stems of lubrication and a considerable number of lubricants available for any given set of operating conditions. Modern industry pays greater attention to the use of the proper lubricants than at previous time because of the increased speeds, pressures, and operating demands placed on equipment and devices.Although one of the main purposes of lubrication is reduce friction, any substance-liquid , solid , or gaseous-capable of controlling friction and wear between sliding surfaces can be classed as a lubricant.V arieties of lubricationUnlubricated sliding. Metals that have been carefully treated to remove all foreign materials seize and weld to one another when slid together. In the absence of such a high degree of cleanliness, adsorbed gases, water vapor ,oxides, and contaminants reduce frictio9n and the tendency to seize but usually result in severe wear。
外文文献翻译(零传动滚齿机滚刀架进给部件设计)
*********学院******学院毕业设计（论文）外文翻译题目零传动滚齿机滚刀架进给部件设计学生姓名 ******专业机械制造工艺及设备学号 0710211110班级 071021B1指导老师 ******职称教授2011年10月8日GNC滚齿机切削的通用数学模型滚齿机的切削原理是一种具有多自由度的切削过程。
在本论文中，我们在数控滚齿机和蜗杆型滚刀切削机原理基础上提出了一个数学模型来模拟一般的6轴滚齿机CMC的生成过程，该齿轮数学模型可用于模拟不同类型的齿轮加工，其中列举了一些例子包括验证数学模型。
此外，新类型的齿轮名为“Helipoid”，可在交叉轴传动使用，使通用齿轮的数学模型可以更方便的生成，并能更透彻的理解和对该类型装置的发展。
1．介绍滚齿，成形，及其他特殊用途的机器被广泛用于生产不同类型的齿轮。
由于容易对刀，效率高，质量可靠，传统滚齿机被用于制造齿轮，斜齿轮和蜗轮。
数控滚齿机的发展使得切削齿轮变得高效率和高精度。
一个齿轮坯装卸时间也大大减少。
通过使用不同制造过程的数控滚齿机，以新颖的形状可以制造出齿轮传动平行，交叉和交叉轴。
然而，数控滚齿机过程是复杂的，由于其刀具复杂的几何形状，以及复杂的刀具设定和多自由度切削运动。
到现在为止，这个主题只收到非常有限的关注。
大多数调查都是包括在涉及齿轮几何形状的基础上有一个自由度刀架（利特文和蔡，1985;利特文，1989）。
多自由度已经很少被人研究。
利特温等人（1975年，1994年）提出了多自由度应用到齿轮的理论概念。
Chakraborty 和Dhande（1977）调查了两个自由度，即Camoid和圆锥形度的空间凸轮的几何形状。
此外，蔡和黄（1994）采用了包络理论来研究Camoid几何。
此外，Mitome（1981）所使用的理论，研究了圆锥齿轮滚齿。
吴（1982）研究了一个具有多自由度滚齿机滚齿的过程。
然而，上述模型不能应用到六轴数控滚齿机，因此，不能充分模拟和开发新型齿轮。
数控机床刀具设计论文中英文资料外文翻译文献综述
数控机床刀具设计中英文资料英语原文：Design Of Tool Machine PropResearch significanceThe original knife machine control procedures are designed individually, not used tool management system, features a single comparison, the knife only has to find the tool knife, knife positioning the shortest path, axis tool change, but does not support large-scale tool.Automatic knife in the knife election, in the computer memory knife-election on the basis of using the Siemens 840 D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its other machine. Automatic tool change systems will be faster growth, reduced tool change time, increase the positioning accuracy tool is an important means to help NC technology development.Tool and inventory components of modern production is an important link in the management, especially for large workshop D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its oth management. The traditional way of account management, and low efficiency, high error rate, and not sharing information and data, tools and the use of state can not track the life cycle, are unable to meet the current information management needs. With actual production, we have to establish a workshop tool for the three-dimensional tool storage system to meet the knife workshop with auxiliary storage and management needs.The system uses optimization technology, a large number of computer storage inventory information, timely, accurate, and comprehensive tool to reflect the inventory situation. The entire system uses a graphical interface, man-machine dialogue tips from the Chinese menu, select various functions can be realized and the importation of all kinds of information. Management system using online help function. Through the workshop management, network management and sharing of information. Have automated inventory management, warehousing management tool, a tool for the management and statistical functions.1.System components and control structureThe entire system, including the structure and electrical machinery control systems.1.1.1Mechanical structure and working principleTool from the stent, drive, drive system, Turret, shielding, control system, and electrical components. Support from the column, beam, the upper and lower guide Central track, and track support component.1) Drive for the system chosen VVVF method. Cone used brake motors, with VVVF by Cycloid reducer through sprocket drive.2) Drag a variable frequency drive system and control technology. VVVF adopted, will speed drive shaft in the normal range adjustment to control the speed rotary turret to 5 ~ 30mm in, the drive shaft into two, two under through sprocket, the two profiled rollers Chain driven rotating shelves. Expansion chain adopted by the thread tight regulation swelling, swelling the regular way. - Conditi D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its at six other Des V oeux a knife, can be categorized with some of knife auxiliary equipment, such as bits, such as turning tools.1.1.2.Electrical Control SystemThis tool storage systems is the main electrical control their shelves for operational control and position control. Operational control equipment, including operation of the start of braking control. Position Control is the main location and address of the shelves for testing.1) Electric Transmission horizontal rotary tool storage systems are the mechanical movements are repeated short-term work system. And the run-time system needs some speed, speed transmission needs, the system will use VVVF method can be used simple structure, reliable operation of the motor and frequency inverter.2) Control of the system is divided into two kinds of manual control and automatic control, manual control as a general reserve and debugging methods of work; ways to the system control computer (IPC) and the control unit (inverter contactor , etc.) consisting of a control system.3) location and positioning accuracy of the system automatically identify the site and location using a detection device tion, timely, accurate, and comprehensive tool to reflect the inventory situation. The entire system uses a graphical interface, man-machine dialogue tips from the Chinese menu, select various functions can be realized and the importation of all kinds of information. Management system using online help function. Through the workshop management, network management and sharing of information. Have automated inventory management, warehousing management tool, a tool for the management and statistical fu as proximity switches, relays through the plate-point isolation and the number plate recorded close to the switching signal acquisition and operation of Hutchison with a Optimal Path addressable identify the current location and shelves of the purpose of the shelf location. In order to enable a more accurate positioning system, adopted two photoelectric switches, to detect the two shelves of the two films.1.2.The functions of the knifeknife The is the role of reserves a certain number of tools, machine tool spindle in hand to achieve the fungibility a disc sc knife in the library with discoid knife, cutting tool along See how vertical arrangement (including radial and axial from knife from knife), along See how radial array into acute or arranged in the form of the knife. Simple, compact, more applications, but are ring-cutter, low utilization of space. Figure 2.7 a) to c). D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its. If the knife cutter knife is the type of library, the chain knives, and other means, in the form of the knifeand capacity according to the Machine Tool to determine the scope of the process.s, but are ring-cutter, low utilization of space. Figure 2.7 a) to c). D features, and the election procedures knife more concise, and com mon typesThe knife is a tool storage devices, the common knife mainly in the following forms:(1) the turret knifeIncluding the first level turret vertical turret and the first two, see Figure 2.6 a) and b):(2) the disc cutterDisc knife in the library with discoid knife, cutting tool along See how vertical arrangement (includingradial and axial from knife from knife), along See how radial array into acute or arranged in the form of theknife. Simple, compact, more applications, but are ring-cutter, low utilization of space. Figure 2.7 a) to c).D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use theknife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of theknife, PLC controlled modular design method, which future production of similar machines will be verybeneficial, it is easy to use its. If the knife storage capacity must be increased to increase the diameter of theknife, then the moment of inertia also increased correspondingly, the election campaign long knife. Toolnumber not more than 32 general. Cutter was multi-loop order of the space utilization knife, but inevitablygiven the knife from complex institutions, applicable to the restricted space Machine Tool storage capacity andmore occasions. Two-disc structure is two smaller capacity knife on both sides of the sub-spindle place, morecompact layout, the number ofapply to small and medium-sizedprocessing center.(3) the chain knife Includingsingle-and multi-ring chain ringchain, chain link can take many forms change, see Figure 2.8 a) to c), the basic structure shown in Figure 2. 8 doFeatures: knife apply to the larger capacity of the occasion, the space of the small number of generally applicable to the tool in the 30-120. Only increase the length of the chain tool will increase the number should not be increased circumferential speed of its moment of inertia of the knife does not increase the disc as large.(4) linear combination knife and the knife libraryThe linear knife simple structure in Figure 2.9, tool single order, the capacity of small knife, used for CNC lathe and drill press on. Because the location of fixed knife, ATC completed action by the spindle without manipulator. The cutter knife is generally the turret combination turret with a combination of the disc cutter knife and the chain combination. Every single knife the knife certificates of smaller, faster tool change. There are also some intensive drum wheel, and the lattice-type magazine for the knife, the knife-intensive though.Small footprint, but because of structural constraints, basically not used for single processing center, the concentration used for FMS for the knife system.1.4 Tool storage capacityTool storage capacity of the first to consider the needs of processing, from the use of point of view,generally 10 to 40 knives, knife will be the utilization of the high, and the structure is compact.1.5 Tool options(1) choose to order processing tool according to the order, followed Add to the knife every knife in the Block. Each tool change, the order of rotation of a cutter knife on location, and remove the need knives, has been used by the cutter knife can be returned to the original Block, can also order Add Block, a knife. However, as the knife in the tool in different processes can not be repeated use of the knife must increase the capacity and lower utilization rate.(2) most of the arbitrary choice of the current system of using arbitrary NC election knives, divided into Daotao coding, coding and memory-cutter, three. Daotao coding tool code or knives or Daotao need to install the code used to identify, in accordance with the general principle of binary coding coding. Tool knife election coding method uses a special knife handle structure, and each of the coding tool. Each of the tool has its own code, thereby cutting tool can be in different processes repeatedly used, not to replace the tool back at the original knife, the knife capacity can be reduced accordingly. Memory-election this paper knife, in this way can knives and knife in the position corresponding to the Daotao memory of the PLC in the NC system, no matter which tool on the Inner knife, tool information is always there in mind, PLC . On the knife with position detection devices, will be the location of each Daotao. This tool can be removed and sent back to arbitrary. On the knife is also a mechanical origin, every election, the nearest knife selection.1.6.Control of the knife(1) the knife as a system to control the positioning axis. In the ladder diagram in accordance with the instructions for computing T code comparison of the output angle and speed of instructions to the knife the knife servo drive servo motor. Tool storage capacity, rotation speed, and / deceleration time, and other system parameters can be set in such a manner free from any outside influence positioning accurate and reliable but the cost is higher.(2) knife from the hydraulic motor drives, fast / slow the points, with proximity switches count and positioning. In comparison ladder diagram of the current storage system knife (knife spindle) and goals knife (pre-knife) and computing, then output rotation instructions, judging by the shortest path rotation in place. This approach requires sufficient hydraulic power and electromagnetic valve knife the rotational speed can be adjusted through the throttle. But over time may be oily hydraulic, oil temperature and environmental factors impact the change in velocity and accuracy. Not generally used in large and medium-sized machine tool change frequently.(3) the knife from AC asynchronous motor driven cam mechanism (Markov institutions), with proximity switches count, which means stable operation, and generally accurate and reliable positioning cam used in conjunction with a mechanical hand, ATC fast-positioning.2. ATC, the main types, characteristics, and the scope of application2.1 Auto Rotary ToolRotary Tool automatically on the use of CNC machine tool is a simpleinstallation of automatic tool change, the Quartet and 47.60 Turret Tool various forms, such as rotary turret were installed on four, six or more of the Tool , NCinstructions by ATC. Rotary Tool has two vertical and horizontal, relatively simple structure, applicable to economic CNC lathe.Rotary Tool in the structure must have good strength and stiffness, resistance to bear rough Cutting Tool in the cutting force and reduce the role of deformation and improve processing accuracy. Rotating Tool to choose reliable positioning programme structure and reasonable position, in order to ensure that each rotary turret to a higher position after repeated positioning accuracy (typically 0.001 to 0.005mm). Figure 2.1 shows the spiral movements of the Quartet Turret.Auto Rotary Tool in the simplest of ATC, is 180 º rotary ATC devices, as shown in Figure 2.2 ATC instructions received, the machine control system put ATC spindle control to the designated location at the same time, the tool movement to the appropriate location, ATC, with the rotary axis and at the same time, the knives matching tool; drawbars from Spindle Cutting Tools rip, ATC, will be the tool from their position removed; ATC, 180 º rotary tool spindle and the tool and tool away; ATC, the Rotary At the same time, thetool refocusing its position to accept Spindle removed from the cutting tool; Next, ATC, will be replaced with the cutter knives were unloaded into the spindle and tool: Finally, back to the original ATC, "standby" position. At this point, ATC completed procedures to continue to run. This ATC, the main advantage of simple structure,the less movement, fast tool change. The main disadvantage is that knives must be kept in parallel with the axis of the plane, and after the home side compared to the tool, chip and liquid-cutting knife into the folder, it is necessary to the tool plus protection. Cone knife folder on the chip will cause ATC error, or even damage knife folders, and the possibility of spindle. Some processing centre at the transfer, and the tool side. When the ATC command is called, the transfer-cutter knives will be removed, the machine go forward, and positioning with the ATC, in line with the position. 180 º "Rotary ATC devices can be used horizontal machine, can also be used for vertical machining centers.2. 2 ATC head-turret installedWith rotating CNC machine tool often used such ATC devices, with a few turret head spindle, each with a spindle on both knives, the first tower interim process can be automatic tool change-realization. The advantage is simple structure, tool change time is short, only about 2 s. However, due to spatial constraints, the number of spindle can not be too much, usually only apply to processes less, not to high precision machine tools, such as the NC drill, such as CNC milling machine. In recent years there has been a mechanical hand and the turret head with a knife for the automatic tool change ATC devices, as shown in Figure 2.3. It is in fact a turret head ATC, and the knife-ATC device combination. The principle is as follows:5 turret on the first two tool spindle 3 and 4, when using the tool spindle 4 processing tool, the manipulator 2 will be the next step to the need for the tool does not work on the tool spindle 3 until after the completion of this process , the first rotary turret 180 º, ATC completed. ATC most of their time and processing time coincidence, the only real tool change time turret transposition of the first time, this approach mainly used for ATC and NC NC drilling file bed.2. 3.Daidao system for the automatic tool changeFigure 2.4 shows the knife and the whole machine tool CNC machine tools for the appearance of Fig. Figure 2.5 shows the knife and split-type machine to the appearance of CNC machine tool plans.At this point, knife storage capacity, a heavier tool can, and often additional transport unit to complete the knife between the spindle and cutting tool transport.Daidao the knife from the ATC, the election knives, automatic loading and unloading machine tool and tool exchange institutions (manipulator), composed of four parts, used widely.Tool Automatic Tool Change When CNC tool code and the code in line with directives of the tool selected, the rotary cutter knives will be sent to the ATC position, waiting to grab manipulator. Random knife election is the advantage of the cutter knife in the order has nothing to do with the processing sequence, the same tool can be used repeatedly. Therefore, the relatively small number of knives, knife the corresponding smaller. Random elections knife on the tool must be coded to identify. There are three main coding.1. Tool coding. Adopt special knife handle structure coding, the drawbars on the knife handle back-endpackages such as spacing of the coding part of the lock-nut fixed. Coding diameter ring diameter of a size two,respectively, said that binary "1" and "0" to the two rings are different, can be a series of code. For example, there are six small diameter of the ring can be made to distinguish between 63 (26-1 = 63) of the coding tool. All of 0 normally not allowed to use the the manipulator system, the whole process more complicated ATC. We must first used in the processing of all installed in the standard tool on the knife handle in the machine outside the pre-size, according to a certain way Add to the knife. ATC, selected first in the knife knife, and then from ATC, from the knife from the knife or spindle, exchange, the new knife into the spindle, the old knife back into the knife.ATC, as the former two knives to accommodate a limited number can not be too many, can not meet the needs of complex parts machining, CNC machine tool Automatic Tool Change Daidao the use of the automatic tool change devices. The knife has more capacity, both installed in the spindle box side or above. As for the automatic tool change Daidao device CNC machine tool spindle box only a spindle, spindle components to high stiffness to meet the machining requirements. The number of establishments in larger knife, which can meet the more complex parts of the machining processes, significantly improving productivity. Daidao system for the automatic tool change applied to drilling centres and CNC machining centers. The comparison drawn Daidao automatic tool change system is the most promising.3.PLC control of the knife random mode of election3. 1Common methods of automatic election knifeAutomatic control of the knife CNC refers to the system after the implementation of user instructions onthe knife library automation process, including the process to find knives and automatic tool change [(63,71]. CNC Machining Center device (CNC) directive issued by the election knife , a knife, the tool required to take the knife position, said the election automatic knife. automatically elected knife There are two ways: randomsequence election knives and knife election method.3.1.1 order election knifeTool Selection order is the process tool according to the sequence of the insert knife, the use of knives in order to take place, used knives back at the original knife, can also order Add Block, a knife. In this way, no need Tool identification devices, and drive control is a relatively simple, reliable and can be used directly from the points of the knife machinery to achieve. But the knives in each of the tool in different processes can not be reused, if the tool is installed in accordance with the order of the knife, there will be serious consequences. Theneed to increase the number of knives and knife the capacity of the tool and reduce the utilization of the knife.3.1.2Random election knifeRandom election under the knife is arbitrary instructions to select the required tools, then there must be tool identification devices. Tool knife in the library do not have the processing in accordance with the order of the workpiece can be arbitrary storage. Each of the tool (or knife blocks) are for a code, automatic tool change, the rotary cutter, every tool have been the "tool identification device" acceptable identification. When CNCtool code and the code in line with directives of the tool selected, the rotary cutter knives will be sent to the ATC position, waiting to grab manipulator. Random knife election is the advantage of the cutter knife in the order has nothing to do with the processing sequence, the same tool can be used repeatedly. Therefore, the relatively small number of knives, knife the corresponding smaller. Random elections knife on the tool must be coded to identify. There are three main coding.1. Tool coding. Adopt special knife handle structure coding, the drawbars on the knife handle back-end packages such as spacing of the coding part of the lock-nut fixed. Coding diameter ring diameter of a size two, respectively, said that binary "1" and "0" to the two rings are different, can be a series of code. For example, there are six small diameter of the ring can be made to distinguish between 63 (26-1 = 63) of the coding tool. All of 0 normally not allowed to use the code, to avoid the cutter knife Block did not confuse the situation.2. Knife Block coding. On the knife Block coding, coding tool, and tool into line with the number of knives in the Block. ATC knife when the rotation, so that each knife seats followed through knowledge knife, knife found blocks, knives stopped the rotation. At this time there is no knife handle encoding part of the knife handle simplified.3. Annex coding methods. This style of coding keys, coded cards, coding and coding-disc, which is the most widely used coding keys. First to knives are attached to a tool of the show wrapped coding keys, and when the cutter knife to the store at knife in, so put the number of keys to remember knife Block Road, will be inserted into key to the coding Block next to the key hole in the seat for the knife to the numbers. ConclusionFocused on in today's manufacturing environment tool storage and management of new models and methods, practical application of good results in systems integration and optimization, and other aspects of operations will be further explored, so that it has a higher theoretical and practical level.译文：机床刀具设计课题研究意义机床原来的刀库控制程序是单独设计的，没有采用刀具管理系统，功能也比较单一，只实现了刀库刀具的找刀、刀库最短路径定位、主轴换刀，而且不支持大型刀具。
【机械类文献翻译】带传动设计
【机械类⽂献翻译】带传动设计英⽂译⽂tape transportAmong the methods of material conveying quantity, belt conveyors play a very important part in the reliable carrying of material over long distances at competitive cost. Conveyor systems have become larger and more complex and drive systems have a l so been going through a process of evolution and will continue to do so. Nowadays, bigger belts require more power and have brought the need for larger individual drives as well as multiple drives such as 3 drives of 750 kW for onebelt(this is the case for the conveyor drives in Chengzhuang Mine). The ability to control drive acceleration torque is critical to belt conveyors' performance. A efficient drive system should be able to provide smooth, soft starts while maintaining belt tensions within the specified safe limits. For load sharing on multiple drives. torque and speed control are also considerations in the drive system's design. Due to the advances in conveyor drive control technology, at present many more reliable.Cost-effective and performance- driven conveyor drive systems covering a wide range of power are available for customers' choices[1].1 tape transport on conveyor drive technologies1. 1 The belt transmission modeFull-voltage starters.With a full-voltage starter design, the conveyorhead shaft is direct-coupled to the motor through the gear drive. Directfull-voltage starters are adequate for relatively low-power, simple- Profile conveyors. With direct full-voltage starters. no control is provided for various conveyor loads and. depending on the ratio between full- and no-load power requirements, empty starting times can be three or four times faster than full load. The maintenance-free starting system is simple, low-cost and very reliable. However, they cannot control starting torque and maximum stall torque; therefore. they are limited to the low-power, simple-profile conveyor belt drives.Reduced-voltage starters.As conveyor power requirements increase,controlling the applied motor torque during the acceleration period becomesincreasingly important. Because motor torque is a function of voltage, motor voltage must be controlled. This can be achieved through reduced-voltage starters by employing a silicon controlled rectifier (SCR). A common starting method with SCR reduced-voltage starters is to apply low voltage initially to take up conveyor belt slack. and then to apply a timed linear ramp up to full voltage and belt speed. However, this starting method will not produce constant conveyor belt acceleration. When acceleration is complete. the SCRs, which control the applied voltage to the electric motor. are locked in full conduction, providing full-line voltage to the motor. Motors with higher torque and pull -vp torque, can provide better starting torque when combined with the SCR starters, which are available in sizes up to 750 KW.Wound rotor induction motors.Wound rotor induction motors are connected directly to the drive system reducer and are a modified configuration of a standard AC induction motor. By inserting resistance in series with the motor's rotor windings. the modified motor control System controls motor torque. For conveyor starting, resistance is placed in series with the rotor for low initial torque. As the conveyor accelerates,the resistance is reduced slowly to maintain a constant acceleration torque. On multiple-drive systems.an external slip resistor may be left in series with the rotor windings to aid in load sharing .the motor systems have a relatively simple a design.However,the control systems for these can be highly complex, because they are based on computer control of the resistance switching. Today, the majority of control systems are custom designed to meet a conveyor system's particular specifications. Wound rotor motors are appropriate for systems requiring more than400KW.DC motor.DC motors. available from a fraction of thousands of KW，are designed to deliver constant torque below base speed and constant KW above base speed to the maximum allowable revolutions per minute (r/min). with the majority of conveyor drives, a .DC shunt wound motor is used. Wherein the motor's rotating armature is connected externally. The most common technology for controlling DC drives is a SCR device. which allows for continual variable-speed operation. The DC drive system is mechanically simple, but can include complex custom-designedelectronics to monitor and control the complete system. this system option is expensive in comparison to other soft-start systems. but it is a reliable, cost-effective drive in applications in which torque,load sharing and variable speed are primaryconsiderations. DC motors generally are used with higher-power conveyors,including complex profile conveyors with multiple-drive systems, booster tripper systems needing belt tension control and conveyors requiring a wide variable-speed range. 1. 2 Hydrokinetic couplingHydrokinetic couplings, commonly referred to as fluid couplings. are composed of three basic elements; the driven impeller, which acts as acentrifugal pump; the driving hydraulic turbine known as the runner anda casing that encloses the two power components. Hydraulic fluid is pumped from the driven impeller to the driving runner, producing torque at the driven shaft. Because circulating hydraulic fluid produces the torque and speed, no mechanical connection is required between the driving and driver shafts.The power produced by this coupling is based on the circulated fluid's amount and density and the torque in proportion to input speed. Because the pumping action within the fluid coupling depends on centrifugal forces. the output speed is less than the input speed. Referred to as slip. this normally is between 1% and 3%. Basic hydrokinetic couplings are available in configurations from fractional to several thousand KW.Fixed-fill fluid couplings.Fixed-fill fluid couplings are the most commonly used soft-start devices for conveyors with simpler belt profiles and limited convex/concave sections. They are relatively simple,low-cost,reliable,maintenance free devices that provide excellent soft starting results to the majority of belt conveyors in use today.Variable-fill drain couplings.Drainable-fluid couplings work on the same principle as fixed-fill couplings. The coupling's impellers are mounted on the AC motor and the runners on the driven reducer high-speed shaft. Housing mounted to the drive base encloses the working circuit. The coupling's rotating casing contains bleed-off orifices that continually allow fluid to exit the working circuit into a。
数控车床毕业设计外文翻译
LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly isthe tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.2 Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC). Prior to the advent of NC, all machine tools ere manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:Electrical discharge machining,Laser cutting,Electron beam welding.Numerical control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tolls and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to made straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps, the smoother is the curve, Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the fur ther development from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 copies of a given part, it was also necessary to run the paper tape through the reader 100 separate tines. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To made even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control (DNC) solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control, machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool an needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.3 TurningThe engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered.The engine lathe has been replaced in today’s production shops by a wide variety of automatic lathes such as automatic of single-point tooling for maximum metal removal, andthe use of form tools for finish on a par with the fastest processing equipment on the scene today.Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilled operator. In redesigning an experimental part for production, economical tolerances should be used.Turret Lathes Production machining equipment must be evaluated now, more than ever before, this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating.In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turrets lathe, the designer should strive for a minimum of operations.Automatic Screw Machines Generally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle automatics and automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts, the automatic screw machine has long since exceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic screw machine. Quantities less than on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities.Automatic Tracer Lathes Since surface roughness depends greatly on material turned, tooling , and feeds and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.In some cases, tolerances of 0.05mm are held in continuous production using but one cut . groove width can be held to 0.125mm on some parts. Bores and single-point finishes can be held to 0.0125mm. On high-production runs where maximum output is desirable, a minimum tolerance of 0.125mm is economical on both diameter and length of turn.车床车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。
齿轮外文文献翻译、中英文翻译、外文翻译
齿在轴向的宽度。
齿腹：节圆和齿底之间的表面。
斜齿轮：这些齿轮的齿相对于齿轮轴线由一个角度或螺旋角度，它们比直齿圆柱齿轮的制造更难，造价更昂贵，但是它们传动无噪音并且可靠。
它们可以用来在相同或不同平面中构成一定角度的相两轴之间的力的传递。
人字形齿轮：人字形齿轮是在齿轮两边有相同数量在左旋和右旋形的齿轮。
由于齿轮有角度，齿轮制造时需要考虑轴受到的轴向力，人字形齿轮是用平衡的方法来抵消轴向推力的，固而允许选用轻系列轴承取代重系列轴承，甚至可以完全取消轴承，通常在切削加工中在齿轮的周围有一个中心槽来抵消。
锥齿轮：锥齿轮用作互相不平行的轴之间的连接。
通常轴之间的夹角是90度，但它们比90多或少，相啮合的两齿轮仅改变运动方向，或者为改变速度具有不同的齿数，齿的表面沿着圆锥的表面，圆头齿之间不相互平行，它就使得在机械加工中产生类似的问题及必须要一套夹具。
齿轮的线可能是直的或螺旋的，因此有平直的锥齿和螺旋的锥齿。
蜗杆和蜗轮：蜗杆蜗轮机构主要用作有限空间需较小齿轮的体积的情况。
通常蜗杆为主动件并且不能颠倒，也就是说，蜗轮不能作为主动件。
许多蜗杆能左右移动，转动为顺时针或逆时针。
齿条：齿条是有无穷半径的齿轮或是边缘随着直线扩展的齿轮，它被用来往复运动改变为螺旋运动或反过来，车床齿条和小齿轮是这种机器的最好例子。
各种材料被用于制造齿轮。
通常被选用的材料取决于齿轮的制造与齿轮将来的实现用途，齿轮能被铸，轧或挤压出来。
材料类型包括：铸铁碳素钢，合金钢，铝，青铜，尼龙。
附录：GearsAbstract: Gear is power element in the machine, is used to pass between the shaft and shaft movement and power. They may just was used to relay movement, that is one part to another part of the machine, or be used to change the relative spee d and torque between shaft and shaft, the first to be discovered with gear machine is horological, in fact, the gear of the clock is very small compared with the gear train. As the widely used in the gear in the actual environment, people in the asp ect of the application of the gear for a lot of research and investigation. now, gear drive than ever to have to pass a heavy load, and under the high speed running. The engineers and mechanics are considering the factors that exist in a mechanical.Keywords: Gear，Strength，check.Super Gears：Spur gears will be considered first for several reasons.In the first place ,they are simplest and the least expensive of gears and they may be used to transmit power betw een parallel shafts,also,spur gears definitions are usually applicable to other types .It is imp ortant go understand the following definitions,since they are important factors in the desig n of any equipment utilizing gears. Diametric Pitch The number of teeth per inch of pitch cirle diameter .The diameter pitch is usually an integer .A small number for the pitch imp lies a large tooth size.Meshing spur gears must have the same diameter pitch .The speed rat io is based on the fact that meshing gears may have different-sized pitch circles and henc e different number of teeth.Circular Pitch：The distance from a point on one tooth to the corresponding point on an adjacent tooth ,m easrued along the pitch circle.This is a liner dimension and thus bas liner units.Pitch Circle：The circle on which the ratio of the gear set is based,when two gears are meshing ,the tw o pitch circles must be exactly tangent if the gears are to function properly.The tangency p oint is known as the pitch point.Pressure Angle：The angle between the line of action and a line perpendicular to the centerlines of the tw o gears in mesing .Pressure Angles for spur gears are usually 14.5 or 20 degrees,although o ther values can be used.Meshing gears must have the same pressure angles.In the case of a rack,the teeth have the straight sides inclined at an angle corresponding to the pressure a ngle.Base Circle：A circle tangent to the line of action (or pressure line ) .The base circle is the imaginary cir cle about which an involutes cure is developed .Most spur gears follow an involutes cure fr om the base circle to the top of the tootch,this cure can be visualized by observing a point o n a taut cord an it is unwound from a cylinder .In a gear ,the cylinder is the best circle.Addendum：The radial distance form the pitch circle to the top of the tooth .Dedendum：The radial distance from file pitch circle to the root of the tooth.Clearance：The difference between the addendum and the addendum.Face Width：The width of the tooth measured axially.Face：The surface between the pitch circle and the top of the tooth.Flank：The surface between the pitch circle and the bottom of the tooth.Helical Gears：These gears have their tooth element at an angle or helix to the axis of the gear.The-y are more difficult and expensive to make than spur gears,but are quieter and stronger. They may be used to transmit power between parallel shafts at an angle to each in the same o r different planes.Herringbone Gears：A herringbone gear is equivalent to a right-hand and a left-hand helical gear placed side b y side.Because of the angle of the tooth,helicalgears create considerable side thrust on the shaft. A herringbone gear corrects this thrust b y neutralizing it ,allowing the use of a small thrust bearing instead of a large one and perha ps eliminating one altogether.Often a central groove is made round the gear for ease in mac hining.Bevel Gears：Bevel gears are used to connect shafts, which are not parallel to each ually the sha fts are 90 deg.To each other, but they may be more or less than 90 deg.The two meshing ge ars may have the same number of teeth for the purpose of changing direction of motion onl y,or they may have a different number of teeth for the purpose of changing both speed an d irection .The faces of the teeth lie on the surface of the frustum of a cone,therefore the te eth elements are not parallel to each other it can be seen that this lack of parallelism create s a machining problem so that two passes with a tool must be made.The tooth elements ma y be straight or spiral ,so that we have plain anti spiral evel gears.Worm and Worm Gears：A worm-and-worm-gear combination is used chiefly where it is desired to obtain a high ge ar reduction in a limited space,normally the worm drivers the worm gear and is not reversi ble ,that is to say,the worm gear can not drivethe worm.Most worms can be rotated in either direction,clockwise or counterclockwise. Ra cks A rack is a gear with an infinite radius,or a gear with its perimeter stretched out into a straight line.It is used to change reciprocating motion to rotary motion or vice versa.A l athe rack and pinion is a good example of this mechanism.Various materials are used in manufacturing gears.Usually,the materials selected depends on the method used for making the gear and the ap注：1. 指导教师对译文进行评阅时应注意以下几个方面：①翻译的外文文献与毕业设计（论文）的主题是否高度相关，并作为外文参考文献列入毕业设计（论文）的参考文献；②翻译的外文文献字数是否达到规定数量（3 000字以上）；③译文语言是否准确、通顺、具有参考价值。
滚齿机传动设计与滚刀调整讲解
1.2滚齿机的发展趋势
滚齿是国内外应用最广的切齿方法，一些国家滚齿机的拥有量约占所有齿轮机床总量的45％- 50％。为适应齿轮加工行业对制造精度、生产效率、提高质量及清洁生产的要求，滚齿机及滚齿加工技术出现了以下几个发展趋势：
①全数控化
所谓的全数控化，指不仅齿轮加工机床的各轴进给运动是数控的，而月．机床的展成运动和差动运动也是数控的，即机床的各运动轴进行CXC控制及轴间实现联动。
为了实现对滚齿机的改进，提高齿轮加工的质量，本课题完成了对传统滚齿机Y3150E的部分设计绘制。本文首先简单介绍了滚齿机的主要结构工作原理和发展趋势。接着详细论述了滚齿机主要传动系统的设计方法，对传动轴进行强度设计和强度校核，对传动齿轮的接触强度、弯曲强度进行设计和强度校核。最后给出滚削齿轮时需要调整机床的各个环节。
滚齿机的传动设计与滚刀调整
摘要
齿轮是现代机械传动中的重要组成部分。从国防机械到民用机械，从重工业机械到轻工业机械，无不广泛的采用齿轮传动。随着汽车、机械、航天等工业领域的高速发展，对齿轮的需求量日益增加，对齿轮加工的效率、质量及加工成本的要求愈来愈高，滚齿机是齿轮加工机床中的一种，由于滚齿机既适合高效率的齿形粗加工，又适合中等精度齿轮的精加工，因此受到广泛的应用。为此，本文对普通滚齿机的设计进行了研究。
数控车床主传动系统毕业设计外文翻译
数控车床主传动系统毕业设计外文翻译数控车床在先进制造技术领域最根本的观念之一是数控(NC)。
数控来临之前，所有机床是手工操作和控制。
手动控制机床有许多限制，或许没有比操作者的技能更突出。
用手动控制，产品质量直接相关，并仅限于操作者的技能。
车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。
车削很少在其他种类的机床上进行，而且任何一种其他机床都不能像车床那样方便地进行车削加工。
由于车床还可以用来钻孔和铰孔，车床的多功能性可以使工件在一次安装中完成几种加工。
因此，在生产中使用的各种车床比任何其他种类的机床都多。
车床的基本部件有:床身、主轴箱组件、尾座组件、溜板组件、丝杠和光杠件在各种速度下回转。
主轴箱基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮(类似于卡车变速箱)所组成。
通过变速齿轮，主轴可以在许多种转速下旋转。
大多数车床有8~12种转速，主轴箱安装在内侧导轨的固定位置上，一般在床身的左端。
它提供动力，并可使工一般按等比级数排列。
而且在现代机床上只需扳动2~4个手柄，就能得到全部转速。
一种正在不断增长的趋势是通过电气的或者机械的装置进行无级变速由于机床的精度在很大程度上取决于主轴，因此，主轴的结构尺寸较大，通常安装在预紧后的重型圆锥滚子轴承或球轴承中。
主轴中有一个贯穿全长的通孔，长棒料可以通过该孔送料。
主轴孔的大小是车床的一个重要尺寸，因此当工件必须通过主轴孔供料时，它确定了能够加工的棒料毛坯的最大尺寸。
这个问题导致了1959年自动编程工具(APT)语言的发展，使用类似数控英文语句来定义几何零件，描述刀具配置，并制定所需的方案。
新的APT语言的发展是重大的一步，推动数控技术的进一步发展。
原来的数控系统广泛使用穿孔纸，后来由磁性塑料带代替。
一个使用穿孔纸的人解释了该机器的磁带使用说明作为知名的数控概念发展(DNC)解决了纸张和塑料带与数控相关作为执行指令的编程语言磁带的问题。
在直接数字控制下，精密机床的束缚，通过数据传输链路，连接在主机和机器工具，通过数据传输连接需要。
毕业论文外文翻译-齿轮的加工方法
英文原文Gear manufacturing methodsThere are two basic methods of manufacturing gear teeth: the generating process and the forming process. when a gear tooth is generated, the workpiece and the cutting or grinding tool are in continuous mesh and the tooth form is generated by the tool. In other words, the work and the tool are conjugated to each other. hobbing :machines, shaper cutters, shaving machines, and grinders use this principle.When a gear tooth is formed, the tool is in the shape of the space that is being machined out. Some grinding machines use this principle with an indexing mechianism which allows the gear teeth to be formed tooth by tooth. Broaches are examples of form tools that machine all the gear teeth simultaneously.shapingShaping is inherently similar to planning but uses a circular cuttrer instead of rack and the resulting reduction in the reciprocating inertia allows much higher stroking speeds: modern shapers cutting car gears can run at 2,000 cutting strokes per minmute. The shape of the cutter is roughly the same as an involute gear but the tips of the teeth are rounded.The generating drive between cutter and workpiece does not involve a rack or leadscrew since only circular motion in involved. The tool and workpiece move tangential typically 0.5 mm for each stroke of the cutter. On the return stroke the cutter must be retracted about 1 mm to give clearance otherwise tool rub occurs on the backstroke and failure is rapid. The speed on this type of machine is limited by the rate at which some 50kg of cutter and bearings can be moved a distance of 1 mm. the accelerations involved tequire forces of the order of 5000N yet high accuracy must be maintained.The advantages of shaping are that production rates are relatively high and that it is possible to cut right up to a shoulder. Unfortunately, for helical gears, a helical guide is required to impose a rotational motion on the stroking motion; such helical guides cannot be produced easily or cheaply so the method is only suitable for long runs with helical gears since special cutters and guides must be manufactured for each different helix angle. A great advantage of shaping is its ability to annular gears such as those required for large epicyclie drives.When very high accuracy is of importance the inaccuracies in the shaping cutter matter since they may transfer to the cut gear. It is obvious that profile errors will transfer but it is less obvious than an eccentrically mounted or ground cutter will give a characteristic “dropped tooth”. There are several causes for “dropped tooth” but it occurs most commonly when the diameter of the workpiece is about half, one and half, two and a half, etc, times the cutter diameter. If the cutter starts on a high point and finishes on a low point during the final finishing revolution of the gear the peak to peak eccentricity errors in the cutter occurs between the last and the first tooth of the final revolution of the cut gear; as the cumulative pitch error of the cutter may well be over 25 microns there is a sudden pitch error of this amount on the cut gear. The next gear cut on the machine may however be very good on adjacent pitch if the final cut happened to start in a favorable position on the cutter.Various attempts have been made to prevent this effect, in particular by continuing rotation without any further cutter infeed but if the shaping machine is not very rigid and the cutter very sharp then no further cutting will occur and the error will not be removed.hobbinghobbing, the most used metal cutting method, uses the rack generating principle but avoids slow reciprocation by mounting many “racks ” on a rotating cutter. The “racks” are displaced axially to form a gashed worm. The “racks” do not generate the correct involute shape for the whole length of the teeth since they are moving on a circular path and so the hob is fed slowly along the teeth either axially in normal or in the direction of the helix in “oblique” hobbing.Metal removal rates are high since no reciprocation of hob or workpiece is required and so cutting speeds of 40 m/min can be used for conventional hobs and up to 150m/min for carbide hobs. Typically with a 100mm diameter hob the rotation speed will be 100rpm and so a twenty tooth workpiece will rotate at 5 rpm. Each revolution of the workpiece will correspond to 0.75mm feed so the hob will advance through the workpiece at about 4mm per minute. For car production roughing multiple start hobs can be used with coarse feeds of 3mm per revolution so that 100 rpm on the cutter, a two-start hob and a 20 tooth gear will give a feed rate of 30mm/minute.The disadvantage of a coarse feed rate is that a clear marking is left on the workpiece, particularly in the root, showing a pattern at a spacing of the feed rate per revolution. This surface undulation is less marked on the flanks than in the root and is not important when there is a subsequent finishing operation such as shaving or grinding. When there are no further operations the feed per revolution must be restricted to keep the undulations below a limit which is usually dictated by lubrication conditions. The height of the undulations in the root of the gear is given by squaring the feed per revolution and dividing by four times the diameter of the hob; 1 mm feed and 100mm diameter gives 2.5 micron high undulations in the root. On the gear flank the undulation is roughly cos70 as large, i.e., about 0.85 micron.Accuracy of hobbing is normally high for pitch and for helix, provided machines are maintained; involute is dependent solely on the accuracy of the hob profile. As the involute form is generated by as many cuts as there are gashes on the hob the involute is not exact, but if there are, say, 14 tangents generating a flank of 20 mm radius curvature about 4 mm high the divergence from a true involute is only about half a micron; hob manufacturing and mounting errors can be above 10 microns. Use of twostart hobs or oblique hobbing gives increased error levels since hob errors of pitching transfer to the cut gear.broachingBroaching is not used for helical gears but is useful for internal spur gears; the principal use of broaching in this context is for internal splines which cannot easily be made by any other method. As with all broaching the method is only economic for large quantities since setup costs are high.The major application of broaching techniques to helical external gears is that used by Gleasons in their G-TRAC machine .this machine operates by increasing the effective radius of a hobbing cutter to infinity so that each tooth of the cutter is travelingin a straight line instead of on a radius. This allows the cutting action to extend over the whole facewidth of a gear instead of the typical 0.75 mm feed per revolution of hobbing. The resulting process gives a very high production rate , more suitable for U.S.A. production volumes than for the relatively low European volumes and so, despite a high initial cost ,is very competitive.Broaching give high accuracy and good surface finish but like all cutting processes is limited to “soft” materials which must be subsequently casehardened or heat treated, giving distortion.ShavingA shaving cutting cutter looks like a gear which has extra clearance at the root and whose tooth flanks have been grooved to give cutting edges. It is run in mesh with the rough gear with crossed axes so that there is in theory point contact with a relative velocity along the teeth giving scraping action. The shaving cutter teeth are relatively flexible in bending and so will only operate effectively when they are in double contact between two gear teeth. The gear and cutter operate at high rotational speeds with traversing of the workface and about 100 mm micron of material is removed. Cycle times can be less than half a minute and the machines are not expensive but cutters are delicate and difficult to manufacture. It is easy to make adjustments of profile at the shaving stage and crowning can be applied. Shaving can be carried out near a shoulder by using a cutter which is plunged in to depth without axial movement; this method is fast but requires more complex cutter design.grindingGrinding is extremely important because it is the main way hardened gear are machined. When high accuracy is required it is not sufficient to pre-correct for heat treatment distortion and grinding is then necessary.The simplest approach to grinding, often termed the Orcutt method. The wheel profile is dressed accurately to shape using single point diamonds which are controlled by templates cut to the exact shape required; 6:1 scaling with a pantograph is often used. The profile wheel is then reciprocated axially along the gear which rotates to allow for helix angle effects; when one tooth shape has been finished, involving typically 100 micron metal removal the gear is indexed to the next tooth space. This method is fairly show but gives high accuracy consistently. Setting up is lengthy because different dressing templates are needed if module, number of teeth, helix angle, or profile correction are changed.The fastest grinding method uses the same principle as hobbing but replaces a gashed and relieved worm by a grinding wheel which is a rack in section. Since high surface speeds are needed the wheel diameter is increased so that wheels of 0.5 m diameter can run at over 2000 rpm to give the necessary 1000 m/min. only single start worms are cut on the wheel but gear rotation speeds are high,100 rpm typically, so it is difficult to design the drive system to give accuracy and rigidity. Accuracy of the process is reasonably high although there is a tendency for wheel and workpiece to deflect variably during grinding so the wheel form may require compensation for machine deflection effects. Generation of a worm shape on the grinding wheel is a slow process since a dressing diamond or roller must not only form the rack profile but has to move axially as the wheel rotates. Once the wheel has been trued, gears can be groundrapidly until redressing is required. This is the most popular method for high production rates with small gear and is usually called the Reishauer method.Large gears are usually generated by the Maag method which is similar to planning in its approach but uses cup grinding wheels of large diameter to form the flanks of the theoretical mating rack. Gears of very large diameter cannot easily be moved so the gear is essentially stationary while the grinding wheel carriage reciprocates in the direction of the helix. The wheel is only in contact over a small part of the facewidth in helical gears so this is not important when only a few gears of this size are made in a year. As with form grinding, after grinding a pair of flanks the gear is indexed to the next pair.A similar method used for medium size gears has stationary wheels, while the rough gear is traversed under the wheels. Corresponding rotational movement of the gear is controlled by steel bands unwrapping from a cylinder of pitch circle diameter so that the motion of gear relative to “rack” is correct.Another method, the Nile approach, uses a wheel which is formed to give the “theoretical mating rack” instead of using two cup wheels as in the Maag method. This approach is best suited to medium precision work on smaller gears and is intermediate in speed between the Reishauer and Maag methods.All grinding processes are slow and costly compared with cutting processed and so are only used when accuracy is essential. A rough rule of thumb is that grinding will increase gear cutting costs by a factor of 10 but the cost of the teeth is often only a small part of the total cost of a gearbox. The accuracies attainable are surprisingly not very dependent on size of gear ; whether a gear is 5 m or 50 m diameter the pitch involute and helix accuracies attainable are of the order of 5 microns or better and more dependent on the skill and patience of the operator and inspectors than on any other factors.It is often assumed that grinding will remove all error generated at the roughing stage. Unfortunately, grinding machines are relatively flexible and so the grinding wheel has a tendency to follow previous errors. The errors will thus be reduced but not completely eliminated unless very many cuts are used; whenever a grinding process is giving in consistent results it is advisable to check the accuracies at the rough-cut stage. The only exception is the form grinding process which will not follow involute errors though it will still allow helix and pitch errors.中文译文齿轮的加工方法加工齿轮轮齿有两种基本的方法：产生过程和形成过程。
机械制造 毕业设计 外文英文文献 翻译 齿轮和齿轮传动
机械制造毕业设计外文英文文献翻译齿轮和齿轮传动Gears and gear driveGears are the most durable and rugged of all mechanical drives. They can transmit high power at efficiencies up to 98% and with long service lives. For this reason, gears rather than belts or chains are found in automotive transmissions and most heavy-duty machine drives. On the other hand, gears are more expensive than other drives, especially if they are machined and not made from power metal or plastic.Gear cost increases sharply with demands for high precision and accuracy. So it is important to establish tolerance requirements appropriate for the application. Gears that transmit heavy loads or than operate at high speeds are not particularly expensive, but gears that must do both are costly.Silent gears also are expensive. Instrument and computer gears tend to be costly because speed or displacement ratios must be exact. At the other extreme, gears operating at low speed in exposed locations are normally termed no critical and are made to minimum quality standards.For tooth forms, size, and quality, industrial practice is to follow standards set up by the American Gear Manufactures AssociationAGMA.Tooth formStandards published by AGMA establish gear proportions and tooth profiles. Tooth geometry is determined primarily by pitch, depth, and pressure angle.Pitch：Standards pitches are usually whole numbers when measured as diametral pitch P. Coarse-pitch gearing has teeth larger than 20 diametral pitch ?usually 0.5 to 19.99. Fine-pitch gearing usually has teeth of diametral pitch 20 to 200.Depth: Standardized in terms of pitch. Standard full-depth have working depth of 2/p. If the teeth have equal addendaas in standard interchangeable gears the addendum is 1/p. Stub teeth have a working depth usually 20% less than full-depth teeth. Full-depth teeth have a larger contract ratio than stub teeth. Gears with small numbers of teeth may have undercut so than they do not interfere with one another during engagement. Undercutting reduce active profile and weakens the tooth.Mating gears with long and short addendum have larger load-carrying capacity than standard gears. The addendum of the smaller gear pinion is increased while that of larger gear is decreased, leaving the whole depth the same. This form is know as recess-action gearing.Pressure Angle: Standard angles are and . Earlier standards include a 14-pressure angle that is still used. Pressure angle affectsthe force that tends to separate mating gears. High pressure angle decreases the contact ratio ratio of the number of teeth in contact but provides a tooth of higher capacity and allows gears to have fewer teeth without undercutting.Backlash: Shortest distances between the non-contacting surfaces of adjacent teeth .Gears are commonly specified according to AGMA Class Number, which is a code denoting important quality characteristics. Quality number denote tooth-element tolerances. The higher the number, the closer the tolerance. Number 8 to 16 apply to fine-pitch gearing.Gears are heat-treated by case-hardening, through-hardening, nitriding, or precipitation hardening. In general, harder gears are stronger and last longer than soft ones. Thus, hardening is a device that cuts the weight and size of gears. Some processes, such as flame-hardening, improve service life but do not necessarily improve strength.Design checklistThe larger in a pair is called the gear, the smaller is called the pinion.Gear Ratio: The number of teeth in the gear divide by the number of teeth in the pinion. Also, ratio of the speed of the pinion to the speed of the gear. In reduction gears, the ratio of input to output speeds.Gear Efficiency: Ratio of output power to input power. includesconsideration of power losses in the gears, in bearings, and from windage and churning of lubricant.Speed: In a given gear normally limited to some specific pitchline velocity. Speed capabilities can be increased by improving accuracy of the gear teeth and by improving balance of the rotating parts.Power: Load and speed capacity is determined by gear dimensions and by type of gear. Helical and helical-type gears have the greatest capacity to approximately 30,000 hp. Spiral bevel gear are normally limited to 5,000 hp, and worm gears are usually limited to about 750 hp.Special requirementsMatched-Set Gearing: In applications requiring extremely high accuracy, it may be necessary to match pinion and gear profiles and leads so that mismatch does not exceed the tolerance on profile or lead for the intended application.Tooth Spacing: Some gears require high accuracy in the circular of teeth. Thus, specification of pitch may be required in addition to an accuracy class specification.Backlash: The AMGA standards recommend backlash ranges to provide proper running clearances for mating gears. An overly tight mesh may produce overload. However, zero backlash is required in some applications.Quiet Gears: To make gears as quit as possible, specify thefinest pitch allowable for load conditions. In some instances, however, pitch is coarsened to change mesh frequency to produce a more pleasant, lower-pitch sound. Use a low pressure angle. Use a modified profile to include root and tip relief. Allow enough backlash. Use high quality numbers. Specify a surface finish of 20 in. or better. Balance the gear set. Use a nonintegral ratio so that the same teeth do not repeatedly engage if both gear and pinion are hardened steel. If the gear is made of a soft material, an integral ratio allows the gear to cold-work and conform to the pinion, thereby promoting quiet operation. Make sure critical are at least 20% apart from operating speeding or speed multiples and from frequency of tooth mesh.Multiple mesh gearMultiple mesh refers to move than one pair of gear operating in a train. Can be on parallel or nonparallel axes and on intersection or nonintersecting shafts. They permit higer speed ratios than are feasible with a single pair of gears .Series trains:Overall ratio is input shaft speed divided by output speed ,also the product of individual ratios at each mesh ,except in planetary gears .Ratio is most easily found by dividing the product of numbers of teeth of driven gears by the product of numbers of teeth of driving gears.Speed increasers with step-up rather than step-down ratios mayrequire special care in manufacturing and design. They often involve high speeds and may creste problems in gear dynamics. Also, frictional and drag forces are magnified which, in extreme cases , may lead to operational problems.Epicyclic Gearing:Normally, a gear axis remains fixed and only the gears rotates. But in an epicyclic gear train, various gears axes rotate about one anther to provide specialized output motions. With suitable clutchse and brakes, an epicyclic train serves as the planetary gear commonly found in automatic transmissions.Epicyclic trains may use spur or helical gears, external or internal, or bevel gears. In transmissions, the epicyclic or planetary gears usually have multiple planets to increase load capacity.In most cases, improved kinematic accuracy in a gearset decreases gear mesh excitation and results in lower drive noise. Gearset accuracy can be increased by modifying the tooth involute profile, by substituting higher quality gearing with tighter manufacturing tolerances, and by improving tooth surface finish. However, if gear mesh excitation generaters resonance somewhere in the drive system, nothing short of a “perfect” gearset will substantially reduce vibration and noise.Tooth profiles are modified to avoid interferences which can result from deflections in the gears, shafts, and housing as teeth engageand disendgage. If these tooth interferences are not compensated for by profile modifications, gears load capacity can be seriously reduced. In addition, the drive will be noisier because tooth interferences generate high dynamic loads. Interferences typically are eliminated by reliving the tooth tip, the tooth flank, or both. Such profile modifications are especially important for high-load , high-speed drives. The graph of sound pressure levelvs tip relief illustrates how tooth profile modifications can affect overall drive noise. If the tip relief is less than this optimum value, drive noise increases because of greater tooth interference; a greater amount of tip relief also increase noise because the contact ratio is decreased.Tighter manufacturing tolerances also produce quietier gears. Tolerances for such parameters as profile error, pitch AGMA quality level. For instance, the graph depicting SPL vs both speed and gear quality shows how noise decreases example, noise is reduced significantly by an increase in accuracy from an AGMA Qn 11 quality to an AGNA Qn 15 quality. However, for most commercial drive applications, it is doubtful that the resulting substantial cost increase for such an accuracy improvement can be justified simply on the basis of reduced drive noise.Previously, it was mentioned that gears must have adequate clearance when loaded to prevent tooth interference during the course of meshing. Tip and flank relief are common profile modifications thatcontrol such interference. Gears also require adequate backlash and root clearance. Noise considerations make backlash an important parameter to evaluate during drive design. Sufficient backlash must be provided under all load and temperature conditions to avoid a tight mesh, which creates excessively high noise level. A tight mesh due to insufficient backlash occurs when the drive and coast side of a tooth are in contact simultaneously. On the other hand, gears with excessive backlash also are noisy because of impacting teeth during periods of no load or reversing load. Adequate backlash should be provided by tooth thinning rather than by increase in center distance. Tooth thinning dose not decrease the contact ratio, whereas an increase in center distance does. However, tooth thinning does reduce the bending fatigue, a reduction which is small for most gearing systems.齿轮和齿轮传动在所有的机械传动形式中，齿轮传动是一种最结实耐用的传动方式。
机械制造专业外文翻译-滚齿机加工
外文原文：In the gear hobbing machine processing , gear requirements , However, the calculation of the differential gear selection especially cumbersome in gear, the helical gear (helical gear) movement and the driving force is to rely on the transmission of axial movement along the access track to achieve the, Helical gear is therefore a direct impact on the machining accuracy of the work of the helical gear stability. And helical gear of all kinds of mechanical processing methods, the first step is the calculation of the differential gear selection.However, due to traditional manual calculation of matching gear is not fast. Precise requirements of the above reasons, we studied differential gear selection algorithm based on the use of computer technology has developed a machine differential gear Select Software, The purpose of choosing this subject is to change the traditional differential gear hobbing machine of choice to find a simple and quick method of high accuracy, to replace the traditional time-consuming and error-prone that the look-up table method, the accuracy of this method is very low, sometimes even adjust the gear machine tools and installation conditions can not be equipped with gear to meet the requirements of the distribution of computing.The use of computer-assisted support options to meet on the set of gear with the requirements. In this paper, the use of computer technology to solve differential gear selection tools that exist in the database form, gear and traditional methods to find the problem of low accuracy, increased machine differential Calculation of gear to find accuracy and speed, the actual production to meet the needs of. Understanding of learning through textbooks differential gear hobbing of computer-assisted selection based on the principles and knowledge, more traditional hanging round the drawbacks of lack of choice. Aware that the choice of a new way the importance of the development.In the early stage of c With a deep understanding of language, according to the actual needs of the work to prepare the diagram c language program, to prepare a set of procedures used to select the right differential gear hobbing machine, debugger interface. Calculation of the transmission ratio and the transmission ratio must meet the conditions of assembly by applying the computer technology has developed a tool to choose software differential gear.Meet the user according to their actual gear machine tool settings with the needs of the situation. Select to differential gear, the gear can detect the correct installationand mating.Understanding of learning through textbooks differential gear hobbing of computer-assisted selection based on the principles and knowledge, more traditional hanging round the drawbacks of lack of choice. Aware of the choice of a new way the importance of the development. In the early stage of c has a profound understanding of the language, according to the actual needs of the work to prepare the diagram c language program, to prepare a set of procedures used to select the right differential gear hobbing machine, debugger interface. Calculation of transmission and the transmission ratio than the assembly must meet the conditions, use of computer technology has developed a tool to choose software differential gear.Meet the user according to their actual gear machine tool settings with the needs of the situation. Options for calculating the differential gear, gear testing whether the correct installation and mating.GOETSGH，D L.Advanced Manufacturing Technology[M].Albany，NY：Delmar Publihers Inc.1990.中文译文：滚齿机加工滚齿机加工齿轮时需要计算挂轮，特别是加工斜齿圆柱齿轮，大质数圆齿轮和用切向走刀加工蜗轮时还需要计算差动挂轮。
数控滚齿机滚刀架传动结构设计
数控滚齿机滚刀架传动结构设计李立强;姜辉【摘要】通过设计一种新型数控滚齿机滚刀架传动结构,提高滚齿机的传动精度和精度稳定性,解决了普通滚齿机滚刀架传动精度和效率低的问题.%The paper describes how to improve transmission accuracy and reliability of hobbing machine by a new type CNC hobbing machine's rolling head transmission structure, and solves the problem of usual rolling head transmission accuracy and low efficiency.【期刊名称】《制造技术与机床》【年(卷),期】2012(000)005【总页数】2页(P87-88)【关键词】四轴联动;数控系统控制;主轴电动机主驱动;伺服电动机Y轴驱动【作者】李立强;姜辉【作者单位】齐重数控装备股份有限公司,黑龙江齐齐哈尔161005;齐重数控装备股份有限公司,黑龙江齐齐哈尔161005【正文语种】中文【中图分类】TG61+2目前，我国现有普通滚齿机滚刀架的传动结构一般为差动传动结构。
由一台主电动机提供动力，主轴的主旋转运动和进给移动是由一台主电动机驱动，通过两套传动链传动，中间需要一套差动机构进行运动的合成与分解，整套传动结构非常复杂，传动精度和效率低。
为了加工不同齿数、模数的齿轮，普通滚齿机需要备用各种模数、齿数的齿轮作为外部调整挂轮用于配凑机床传动比，以适应加工各种模数、齿数齿轮的需要。
每加工一种齿轮，操作者都需要相应计算机床传动链的传动比，更换调整传动比用的挂轮。
普通滚齿机对机床操作者的能力依赖性非常高，每加工一种齿轮，操作者都需要试切工件，检验所加工齿轮的齿数是否满足要求。
机床自动化成度低，工人加工工件时的劳动强度和风险大，普通滚齿机的操作、使用极不方便。
(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。
机械毕业设计英文外文翻译75齿轮
附录GEARSGears transmit power and motion between moving pasts. Positive transmission of power is accomplished by projections or teeth on the circumference of the gear . There is no slippage as with friction and belt drives , a feature most machinery requires ,because exact speed ratios are essential .Friction drives are used in industry ,where high speeds and light loads are required and where loads subject to impact are transmitted.When the teeth are built up on the circumference of two rolling disks in contact, recesses must be Provided between the teeth are developed is known as the pitch circle .It is an imaginary circle with the same diameter as a disk that would cause the same relative motion as the gear. All gear design calculations are based on the diameter of the pitch circle. A portion of a gear is shown in Figure 22.13.Gear NomenclatureThe system of gearing used in the United States is known as the involutes system, because the profile of a gear tooth is principally an involutes curve. An involutes is a curve generated on the circle, the normal of which are all tangent to this circle. The method of generating involutes is shown in Figure 22.14. Assume that a string having a pencil on its end is wrapped around a cylinder. The curve described by pencil as the string is unwound is an involutes, and the cylinder on which it is wound is known as the base circle. The portion of the gear tooth from the base at point a in the figure to the outside diameter at point c is an involutes curve and is the portion that contacts other teeth.. From point b topoint the profile of the base circle on which the involutes is described is inside the pitch circle and is dependent on the angle of thrust of the dear teeth. The relationship existing between the diameter of the pitch circle, D, is Db = Dcosθwhere Db = diameter of base circle θ=Angle of thrust between gear tooth.The two commonsystems have their thrust angles or lines of action at 141/2︒and 20︒.Figure 22.13 Nomencla ture for Involute spur gearOther angles are possible, but with larger angles the radial force component tending to force the gears apart becomes greater. If a common tangent is drawn to the pitch circles of two meshing gears. The base circle on which the involutes are drawn are tangent to the line of action.Most gears transmitting power use the 200, full-deep, involutes tooth form. These gears have the same tooth proportion as the 141/20 full–depth involutes but are stronger at their base because of greater thickness. The 200, fine –pitch involutes gears are-similar to the regular 200 involutes and are made in sizes ranging from 20 to 200 diametral pitch. These gears are used primarily for transmitting motion rather the power. The 200 stub tooth gear has smaller tooth depth than the 200. Full –depth gear and is consequently stronger. Involutes gears fulfill all laws of gearing and have the advantage over some other curves in that the contact action is affected by slight variation of gear center distance.Figure 22.14 Mothod of genera an Involute tooth surfaceThe nomenclature of a gear tooth is illustrated in Figure 22.13. the principal definitions and tooth parts for standard 141/20 and 200 involutes gears are discussed here.The addendum of a tooth is the radial distance from the pitch circle to the outside diameter of addendum circle. Numerically, it is equal to 1 divided by the diametral pitch P.The addendum is the radial distance from the pitch circle to the root or addendum circle. It is equal to the addendum plus the tooth clearance.Tooth thickness is the thickness of the tooth measure on the pitch circle. For cut gears the tooth thickness and tooth space are equal. Cast gears are provided with some backlash, the difference between the tooth thickness and tooth space measured on the pitch circle.The face of a gear tooth is that surface lying between the pitch circle and the addendum circle.The flank of a gear tooth is that surface lying between the pitch circle and the root circle.Clearance is a small distance provided so that the top of a meshing tooth will not touch the bottom land of the other gear as it passes the line of centers.Table 22.2gives the proportions of standard 141/200 involutes gears expressed in term of diametral pitch P and number of teeth N.Table 22.2 American Gear Manufactures Association Standard for Involute GearingPitch of GearsThe circuit pitch p is the distance from a point on one tooth to the corresponding point on an adjacent tooth, and is measured on the pitch circle. Expressed as an equation.Metrical gearing is based on the module(mod) instead of the diametral pitch p, as in the English system. The basic metric module formula is mod =D/N=amount of pitch diameter per tooth =millimeters per tooth measured on the pitch diameter. Also, mod=1/p is expressed in millimeters. Also, mod p=25.4.P = πD/N where D = diameter of the pitch circleN = number of teethThe diametral pitch p, often referred to as the pitch of a gear is the ratio of the number of teeth to the pitch diameter. It may be expressed by the following equation: P = N/DUpon multiplying these two equations the following relationship between circular and diametral pitch results.Hence,knowing the value of either pitch we may obtail the other by dividing into π.Gears and gear cutters are standardized according to diametral pitch. This pitch can be expressed in even figures or fractions. Circular pitch, being an actual distance,it is expressed in inches and fractions of an inch. A 6-inth gear (6diametral pitch) is one that has 6teeth per inch of pitch diameter . If the pitch diameter is 3 inch, the number of teeth is 3 x 6 or 18.The outside diameter of the gear is equal to the pitch diameter plus twice the addendum distance or 3 in.+2 x 1/6,which is 3.333in.Any involutes gear of a given diametral pitch will mesh properly with a gear of any other size of the same diametral pitch. However, in cutting gears of various diameters a slight difference in the cutter is necessary to allow for the change in curvature of the involutes as the diameter increases. The extreme case would be a rack tooth ,which would have a straight line as the theoretical tooth profile. For practical reasons the number of teeth in an involutes gear should not be less than 12.Gear speedThe speeds in rooms ,s and S, of two meshing gears vary inversely with both the pitch diameter and the number of teeth .This may be expressed as follows:Figure 22.15 Nomenclature for meshing gear and pinons/S = D/d =T/twhere Dand d represent pitch diameter as included as indicated in Figure 22.15.T and t represent number of teeth on the gear and pinion.Center distance : L = (D+d)/2The speed ratio for a worm gear set depends on the number of teeth on the gear and the lead of the worm. For a single=threaded worm the ratio isRpm worm/rpm gear = T/tKinds of gearsThe gears most commonly used are those that transmission power between two parallel shafts. Such gears having their tooth elements parallel to the ratating shaftsare known as spur gears, the smaller of the two being known as a pinion (Figure 22.15).If the elements of the teeth are twisted or helical,as known in figure 22.16B,they are known as helical gears. These gears amay be for connecting shafts that are at an angle in the same or different planes. Helical gears are smooth acting because there is always more than one tooth in contact. Some power is lost because of end thrust, and provision must be made to compensate for this thrust in the bearings. The herringbone gear is equivalent to two helical gears, one having right-hand and the other a left-hand helix.Figre 22.17 All elements of straight bevel converge at the one opex of the gears Usually, when two shafts are in the same plane but at an angle with one another, a bevel gear is used. Such a gear is similar in appearance to the frustum of a cone having all the elements of the teeth intersecting at a point, as shown in Figure 22.17. Bevel gears are made with either straight or spiral teeth. When the shafts are at right angles and the two bevel gears are the same size, they are known as miter gears (figure 22.16A). Hypoid gears, an interesting modification of bevel gears shown as Figure 22.16F, have their shaft at right angles by they do not intersect as do the shaft for bevel gears. Correct teeth for these gears are difficult to construct, although a generating process has been developed that produces satisfactory teeth. Zero gears (Figure 22.16D)have curved teeth but have a zero helical angle. They are produced on machines that cut spiral bevels and hypoids. Worm gearing is used where a large speed reduction is desired. The small driving gear is called a worm and the driving gear is called a worm and the driven gear a wheel. The worm resembles a large screw and is set in close to the wheel circumference, the teeth of the wheel being curving toconform to the diameter of the worm. The shafts for such gears are at right angles but not in the same plane. These gears are similar to helical gears in their application, but differ considerably in appearance and method of manufacture. A worm gear set is shown in Figure 22.16C.Rack gears, which are straight and have no curvature, represent a gear of infinite radius and are used in feeding mechanisms and for reciprocating. They may have either straight or helical teeth. If the rack is bent in the form of a circle, it becomes a bevel gear having a cone apex angle of 180ºknown as crown gear. the teeth all converge at the center of the disk and mesh properly with a bevel gear of the same pitch. A gear with internal teeth, known as an annular gear, can be cut to mesh with either a spur or bevel gear, depending on whether the shafts are parallel or intersecting.Methods of Making GearsMost gears are produced by some machining process. Accurate machine work is essential for high-speed, long-wearing, quite-operating gears. Die and investment casting of gears has proved satisfactory, but the materials are limited to low-temperature-melting metals and alloys. Consequently, these gears do not have the wearing qualities of heat-treated steel gears. Stamping though reasonably accurate, can be used only in making thin gears from sheet metal.Commercial methods employed in producing gears are summarized as follows: A: Casting 1.sand casting 2.Die casting 3.Precision and investment castingB: StampingC: Machining 1.Formed-tooth process a. From cutter in milling machine b. From cutter in broaching machine c. From cutter in shaper 2.Template process 3.Cutter generating process a. cutter gear b. Hobbing c. Rotary cutter d. Reciprocating cutters simulating a rackD: Power metallurgyE: ExtrudingF: RollingG: GrindingH: Plastic moldingForm Tooth ProcessA formed milling cutter, as shown in Figure22.18,is commonly used for cutting a spur gear. Such a cutter used on a milling machine is formed according to the shape of the tooth space to de removed. Theoretically, there should be a different-shape cutter for each size gear of a given pitch as there is a slight change in the curvature of the involutes. However, one cutter can be used for several gears having different numbers of teeth without much sacrifice in their operation. Each pitch cutter is made in eight slightly varying shapes to compensate for this change.They vary from no.1, which is used to cut gears from 135 teeth to a rack, to no.8, which cuts gears having 12 or 13 teeth. The eight standard involutes cutters are listed in Table 22.3.Setup of a milling machine to cut spur gears are illustrated in Figure 22.18. A discussion of this process is given the chapter on milling is an accurate process for cutting spur, helical, and worm gears. Although sometimes used for bevel gears, the process is not accurate because of the gradual change in tooth thickness. When used for bevel gears at least two cuts are necessary for each tooth space. The usual practice is to take one center cut of proper depth and about equal to the space at the small end of the tooth. Two shaving cuts are then on each side of the tooth space to give the tooth its proper shape.Figure 22.18 Setup for cutting a spir gear on a milling machineTable 22.3 Standard Involute cuttersNo.1135 teeth to a rackNo.255 to 134 teethNo.335 to 54 teethNo.426 to 34 teethNo.521 to 25 teethNo.617 to 20 teethNo.714 to 16 teethNo.812 to 13 teethThe formed-tooth principle may also be utilized in a broaching machine by making the broaching tool conform to the teeth space. Small internal gears can be completely cut in one pass by having a round broaching tool made with the same number of cutters as the gear has teeth. Broaching tool is limited to large-scale production because of the cost of cutters.齿轮运动部件之间的能量和运动由齿轮来传递。
机械专业毕业设计外文翻译10
翻译部分英文部分ADV ANCED MACHINING PROCESSESAs the hardware of an advanced technology becomes more complex, new and visionary approaches to the processing of materials into useful products come into common use. This has been the trend in machining processes in recent years.. Advanced methods of machine control as well as completely different methods of shaping materials have permitted the mechanical designer to proceed in directions that would have been totally impossible only a few years ago.Parallel development in other technologies such as electronics and computers have made available to the machine tool designer methods and processes that can permit a machine tool to far exceed the capabilities of the most experienced machinist.In this section we will look at CNC machining using chip-making cutting tools. CNC controllers are used to drive and control a great variety of machines and mechanisms, Some examples would be routers in wood working; lasers, plasma-arc, flame cutting, and waterjets for cutting of steel plate; and controlling of robots in manufacturing and assembly. This section is only an overview and cannot take the place of a programming manual for a specific machine tool. Because of the tremendous growth in numbers and capability of comp uters ,changes in machine controls are rapidly and constantly taking place. The exciting part of this evolution in machine controls is that programming becomeseasier with each new advanced in this technology.Advantages of Numerical ControlA manually operated machine tool may have the same physical characteristics as a CNC machine, such as size and horsepower. The principles of metal removal are the same. The big gain comes from the computer controlling the machining axes movements. CNC-controlled machine tools can be as simple as a 2-axis drilling machining center (Figure O-1). With a dual spindle machining center, the low RPM, high horsepower spindle gives high metal removal rates. The high RPM spindle allows the efficient use of high cutting speed tools such as diamonds and small diameter cutters (Figure O-2). The cutting tools that remove materials are standard tools such as milling cutters, drills, boring tools, or lathe tools depending on the type of machine used. Cutting speeds and feeds need to be correct as in any other machining operation. The greatest advantage in CNC machining comes from the unerring and rapid positioning movements possible. A CNC machine does dot stop at the end of a cut to plan its next move; it does not get fatigued; it is capable of uninterrupted machining error free, hour after hour. A machine tool is productive only while it is making chips.Since the chip-making process is controlled by the proper feeds and speeds, time savings can be achieved by faster rapid feed rates. Rapid feeds have increased from 60 to 200 to 400 and are now often approaching 1000 inches per minute (IPM). These high feed rates can pose a safety hazard to anyone within the working envelope of the machine tool.Complex contoured shapes were extremely difficult to product prior to CNC machining .CNC has made the machining of these shapes economically feasible. Design changes on a part are relatively easy to make by changing the program that directs the machine tool.A CNC machine produces parts with high dimensional accuracy and close tolerances without taking extra time or special precautions, CNC machines generally need less complex work-holding fixtures, which saves time by getting the parts machined sooner. Once a program is ready and production parts, each part will take exactly the same amount of time as the previous one. This repeatability allows for a very precise control of production costs. Another advantage of CNC machining is the elimination of large inventories; parts can be machined as needs .In conventional production often a great number of parts must be made at the same time to be cost effective. With CNC even one piece can be machined economically .In many instances, a CNC machine can perform in one setup the same operations that would require several conventional machines.With modern CNC machine tools a trained machinist can program and product even a single part economically .CNC machine tools are used in small and large machining facilities and range in size from tabletop models to huge machining centers. In a facility with many CNC tools, programming is usually done by CNC programmers away from the CNC tools. The machine control unit (MCU) on the machine is then used mostly for small program changes or corrections. Manufacturing with CNC tools usually requires three categories of persons. The first is the programmer, who is responsible for developing machine-ready code. The next person involved is the setup person, who loads the raw stork into the MCU, checks that the co rrect tools are loaded, and makes the first part. The third person is the machine and unloads the finished parts. In a small company, one person is expected to perform all three of these tasks.CNC controls are generally divided into two basic categories. One uses a ward address format with coded inputs such as G and M codes. The other users a conversational input; conversational input is also called user-friendly or prompted input. Later in this section examples of each of these programming formats in machining applications will be describes.CAM and CNCCAM systems have changed the job of the CNC programmer from one manually producing CNC code to one maximizing the output of CNC machines. Since CNC machine tools are made by a great number of manufacturers, many different CNC control units are in use. Control units from different manufacturers use a variety of program formats and codes. Many CNC code words are identical for different controllers, but a great number vary from one to another.To produce an identical part on CNC machine tools with different controllers such as one by FANCU, OKUMA or DYNAPATH, would require completely different CNC codes. Each manufacturer is constantly improving and updating its CNC controllers. These improvements often include additional code words plus changes in how the existing code works.A CAM systems allows the CNC programmer to concentrate on the creation of an efficient machining process, rather then relearning changed code formats. A CNC programmer looks atthe print of a part and then plans the sequence of machining operations necessary to make it (Figure O-3). This plan includes everything, from the selection of possible CNC machine tools, to which tooling to use, to how the part is held while machining takes place. The CNC programmer has to have a thorough understanding of all the capacities and limitations of the CNC machine tools that a program is to be made for. Machine specifications such as horsepower, maximum spindle speeds, workpiece weight and size limitations, and tool changer capacity are just some of the considerations that affect programming.Another area of major importance to the programmer is the knowledge of machining processes. An example would be the selection of the surface finish requirement specified in the part print. The sequence of machining processes is critical to obtain acceptable results. Cutting tool limitations have to be considered and this requires knowledge of cutting tool materials, tool types, and application recommendations.A good programmer will spend a considerable amount of time in researching the rapidly growing volume of new and improved tools and tool materials. Often the tool that was on the cutting edge of technology just two years ago is now obsolete. Information on new tools can come from catalogs or tool manufacturers' tooling engineers. Help in tool selection or optimum tool working conditions can also be obtained from tool manufacturer software. Examples would be Kennametal's "TOOLPRO", software designed to help select the best tool grade, speed, and feed rates for different work materials in turning application. Another very important feature of "TOOLPRO" is the display of the horsepower requirement for each machining selection. This allow the programmer to select a combination of cutting speed, feed rate, and depth of cut that equals the machine's maximum horsepower for roughing cuts. For a finishing cut, the smallest diameter of the part being machined is selected and then the cutting speed varied until the RPM is equal to the maximum RPM of the machine. This helps in maximizing machining efficiency. Knowing the horsepower requirement for a cut is critical if more than one tool is cutting at the same time.Software for a machining center application would be Ingersoll Tool Company's "Actual Chip Thickness", a program used to calculate the chip thickness in relation to feed-per-tooth for a milling cutter, especially during a shallow finishing cut. Ingersoll's "Rigidity Analysis" software ealculates tool deflection for end mills as a function of tool stiffness and tool force.To this point we looked at some general qualifications that a programmer should possess. Now we examine how a CAM system works. Point Control Company's SmartCam system uses the following approach. First, the programmer makes a mental model of the part to be machined. This includes the kind of machining to be performed-turning or milling. Then the part print is studied to develop a machining sequence, roughing and finishing cuts, drilling, tapping, and boring operations. What work-holding device is to be used, a vise or fixture or clamps? After these considerations, computer input can be started. First comes the creation of a JOBPLAN. This JOBPLAN consists of entries such as inch or metric units, machine type, part ID, type of workpiece material, setup notes, and a description of the required tools.This line of information describes the tool by number, type, and size and includes theappropriate cutting speed and feed rate. After all the selected tools are entered, the file is saved.The second programming step is the making of the part. This represents a graphic modeling of the projected machining operation. After selecting a tool from the prepared JOBPLAN, parameters for the cutting operation are entered. For a drill, once the coordinate location of the hole and the depth are given, a circle appears on that spot. If the location is incorrect, the UNDO command erases this entry and allows you to give new values for this operation. When an end mill is being used, cutting movements (toolpath) are usually defined as lines and arcs. As a line is programmed, the toolpath is graphically displayed and errors can be corrected instantly.At any time during programming, the command SHOWPATH will show the actual toolpath for each of the programmed tools. The tools will be displayed in the sequence in which they will be used during actual machining. If the sequence of a tool movement needs to be changed, a few keystrokes will to that.Sometimes in CAM the programming sequence is different from the actual machining order. An example would be the machining of a pocket in a part. With CAM, the finished pocket outline is programmed first, then this outline is used to define the ro ughing cuts to machine the pocket. The roughing cuts are computer generated from inputs such as depth and width of cut and how much material to leave for the finish cut. Different roughing patterns can be tried out to allow the programmer to select the most efllcient one for the actual machining cuts. Since each tool is represented by a different color, it is easy to observe the toolpath made by each one.A CAM system lets the programmer view the graphics model from varying angles, such as a top, front, side, or isometric view. A toolpath that looks correct from a top view, may show from a front view that the depth of the cutting tool is incorrect. Changes can easily be made and seen immediately.When the toolpath and the sequence of operations are satisfactory, machine ready code has to be made. This is as easy as specifying the CNC machine that is to be used to machine the part. The code generator for that specific CNC machin e during processing accesses four different files. The JOBPLAN file for the tool information and the GRAPHICE file for the toolpath and cutting sequence. It also uses the MACHINE DEFINE file which defines the CNC code words for that specific machine. This file also supplies data for maximum feed rates, RPM, toolchange times, and so on. The fourth file taking part in the code generating process is the TEMPLATE file. This file acts like a ruler that produces the CNC code with all of its parts in the right place and sequence. When the code generation is complete, a projected machining time is displayed. This time is calculated from values such as feed rates and distances traveled, noncutting movements at maximum feed rates between points, tool change times, and so on. The projected machining time can be revised by changing tooling to allow for higher metal removal rates or creating a more efficient toolpath. This display of total time required can also be used to estimate production costs. If more then one CNC machine tool is available to machine this part, making code and comparing the machining time may show that one machine is more efficient than the others.CAD/CAMAnother method of creating toolpath is with the use of a Computer-aided Drafting (CAD) file. Most machine drawings are created using computers with the description and part geometry stored in the computer database. SmartCAM, though its CAM CONNECTION, will read a CAD file and transfer its geometry represents the part profile, holes, and so on. The programmer still needs to prepare a JOBPLAN with all the necessary tools, but instead of programming a profile line by line, now only a tool has to be assigned to an existing profile. Again, using the SHOWPA TH function will display the toolpath for each tool and their sequence. Constant research and developments in CAD/CAM interaction will change how they work with each other. Some CAD and CAM programs, if loaded on the same computer, make it possible to switch between the two with a few keystrokes, designing and programming at the same time.The work area around the machine needs to be kept clean and clear of obstructions to prevent slipping or tripping. Machine surfaces should not be used as worktables. Use proper lifting methods to handle heavy workpieces, fixtures, or heavy cutting tools. Make measurements only when the spindle has come to a complete standstill. Chips should never be handled with bare hands.Before starting the machine make sure that the work-holding device and the workpiece are securely fastened. When changing cutting tools, protect the workpiece being machined from damage, and protect your hands from sharp cutting edges. Use only sharp cutting tools. Check that cutting tools are installed correctly and securely.Do not operate any machine controls unless you understand their function and what the y will do.The Early Development Of Numerically Controlled Machine ToolsThe highly sophisticated CNC machine tools of today, in the vast and diverse range found throughout the field of manufacturing processing, started from very humble beginnings in a number of the major industrialized countries. Some of the earliest research and development work in this field was completed in USA and a mention will be made of the UK's contribution to this numerical control development.A major problem occurred just after the Second World War, in that progress in all areas of military and commercial development had been so rapid that the levels of automation and accuracy required by the modern industrialized world could not be attained from the lab our intensive machines in use at that time. The question was how to overcome the disadvantages of conventional plant and current manning levels. It is generally ackonwledged that the earliest work into numerical control was the study commissioned in 1947 by the US governme nt. The study's conclusion was that the metal cutting industry throughout the entire country could not copy with the demands of the American Air Force, let alone the rest of industry! As a direct result of the survey, the US Air Force contracted the Persons Corporation to see if they could develop a flexible, dynamic, manufacturing system which would maximize productivity. TheMassachusetts Institute of Technology (MIT) was sub-contracted into this research and development by the Parsons Corporation, during the period 1949-1951,and jointly they developed the first control system which could be adapted to a wide range of machine tools. The Cincinnati Machine Tool Company converted one of their standard 28 inch "Hydro-Tel" milling machines or a three-axis automatic milling made use of a servo-mechanism for the drive system on the axes. This machine made use of a servomechanism for the drive system on the axes, which controlled the table positioning, cross-slide and spindle head. The machine cab be classified as the first truly three axis continuous path machine tool and it was able to generate a required shape, or curve, by simultaneous slide way motions, if necessary.At about the same times as these American advances in machine tool control were taking Place, Alfred Herbert Limited in the United Kingdom had their first Mutinous path control system which became available in 1956.Over the next few years in both the USA and Europe, further development work occurred. These early numerical control developments were principally for the aerospace industry, where it was necessary to cut complex geometric shapes such as airframe components and turbine blades. In parallel with this development of sophisticated control systems for aerospace requirements, a point-to-point controller was developed for more general machining applications. These less sophisticated point-to-point machines were considerably cheaper than their more complex continuous path cousins and were used when only positional accuracy was necessary. As an example of point-to-point motion on a machine tool for drilling operations, the typical movement might be fast traverse of the work piece under the drill's position-after drilling the hole, anther rapid move takes place to the next hole's position-after retraction of the drill. Of course, the rapid motion of the slideways could be achieved by each axis in a sequential and independent manner, or simultaneously. If a separate control was utilisec for each axis, the former method of table travel was less esse ntial to avoid any backlash in the system to obtain the required degree of positional accuracy and so it was necessary that the approach direction to the next point was always the same.The earliest examples of these cheaper point-to-point machines usually did not use recalculating ball screws; this meant that the motions would be sluggish, and sliderways would inevitably suffer from backlash, but more will be said about this topic later in the chapter.The early NC machines were, in the main, based upon a modified milling machine with this concept of control being utilized on turning, punching, grinding and a whole host of other machine tools later. Towards the end of the 1950s,hydrostatic slideways were often incorporated for machine tools of highly precision, which to sonic extent overcame the section problem associated with conventional slideway response, whiles averaging-out slideway inaccuracy brought about a much increased preasion in the machine tool and improved their control characteristics allows "concept of the machining center" was the product of this early work, as it allowed the machine to manufacture a range of components using a wide variety of machining processes at a single set-up, without transfer of workpieces to other variety machine tools. A machining center differed conceptually in its design from that of a milling machine, In that thecutting tools could be changed automatically by the transfer machanism, or selector, from the magazine to spindle, or vice versa.In this ductively and the automatic tool changing feature enabled the machining center to productively and efficiently machine a range of components, by replacing old tools for new, or reselecting the next cutter whilst the current machining process is in cycle.In the mid 1960s,a UK company, Molins, introduced their unique "System 24" which was meant represent the ability of a system to machine for 24 hours per day. It could be thought of as a "machining complex" which allowed a series of NC single purpose machine tools to be linked by a computerized conveyor system. This conveyor allowed the work pieces to be palletized and then directed to as machine tool as necessary. This was an early, but admirable, attempt at a form of Flexible manufacturing System concept, but was unfortunately doomed to failure. Its principal weakness was that only a small proportion of component varieties could be machine at any instant and that even fewer work pieces required the same operations to be performed on them. These factors meant that the utilization level was low, coupled to the fact that the machine tools were expensive and allowed frequent production bottlenecks of work-in-progress to arise, which further slowed down the whole operation.The early to mid-1970s was a time of revolutionary in the area of machine tool controller development, when the term computerized numerical control (CNC) became a reality. This new breed of controllers gave a company the ability to change work piece geometries, together with programs, easily with the minimum of development and lead time, allowing it to be economically viable to machine small batches, or even one-off successfully. The dream of allowing a computerized numerical controller the flexibility and ease of program editing in a production environment became a reality when two ralated factors occurred.These were:the development of integrated circuits, which reduces electronics circuit size, giving better maintenance and allowing more standardization of desing; that general purpose computers were reduced in size coupled to the fact that their cost of production had fallen considerably.The multipie benefits of cheaper electorics with greater reliability have result in the CNC fitted to the machine tools today, with the power and sophistication progtessing considerably in the last few years, allowing an almost artificial intelligence(AI) to the latest systems. Over the years, the machine tools builders have produced a large diversity in the range of applications of CNC and just some of those development will be reviewed in V olume Ⅲ。
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滚齿机传动设计与滚刀调整摘要齿轮是现代机械传动中的重要组成部分。
从国防机械到民用机械,从重工业机械到轻工业机械,无不广泛的采用齿轮传动。
随着汽车、机械、航天等工业领域的高速发展,对齿轮的需求量日益增加,对齿轮加工的效率、质量及加工成本的要求愈来愈高,滚齿机是齿轮加工机床中的一种,由于滚齿机既适合高效率的齿形粗加工,又适合中等精度齿轮的精加工,因此受到广泛的应用。
为此,本文对普通滚齿机的设计进行了研究。
为了实现对滚齿机的改进,提高齿轮加工的质量,本课题完成了对传统滚齿机Y3150E的部分设计绘制。
本文首先简单介绍了滚齿机的主要结构工作原理和发展趋势。
接着详细论述了滚齿机主要传动系统的设计方法,对传动轴进行强度设计和强度校核,对传动齿轮的接触强度、弯曲强度进行设计和强度校核。
最后给出滚削齿轮时需要调整机床的各个环节。
本文对从事滚齿机的设计和改造相关人员具有一定的参考价值,还可供从事齿轮加工的企业员工参考, 从而完成高效率、高质量齿轮的加工。
关键词:滚齿机,传动设计,滚齿机调整,滚刀调整Gear hobbling machine design and hob adjustmentABSTRACTModern mechanical transmission gear is an important component. From mechanical to civil defense machinery, from heavy machinery to light machinery, are all widely used gear. With the auto, machinery, aerospace and other industrial areas of rapid development, increasing demand on the gear, gear processing efficiency, quality and processing costs are rising ever higher, gear hobbling machine is a machine tool in as hobbling machine for high efficiency both roughing tooth, but also for middle-precision gear finishing, so by the wide range of applications. To this end, the paper design of the ordinary hobbling machine was studied ?In order to realize improvements in gear hobbling machine, gear cutting to improve the quality, the subject completed a traditional part of the design drawing Y3150E hobbling machine. First, this article introduces the working principle of the main structure hobbling and development. Then discusses in detail the main drive gear hobbling machine design method, the strength of the transmission shaft design and strength check of gear contact strength, bending strength design and strength check. Finally, gear hobbling machine when the need to adjust the various links In this paper, the design and renovation in hobbling related personnel have some value, but also for employees engaged in information processing gear, thus completing the high efficiency, high-quality gears.KEY WORDS: Hobbling machine, Transmission design, Hobbling machine adjustments, Hob adjustment目录前言 1第1章滚齿机概述 21.1滚齿机工作原理及滚齿机分类 21.1.1滚齿机工作原理 21.1.2滚齿机特点 31.1.3滚齿机分类 31.2滚齿机的发展趋势 5第2章滚齿机传动设计72.1滚齿机主传动72.2传动系统的设计82.2.1设计分析82.3 齿轮的设计92.3.1齿轮传动的设计与强度校核92.3.2低速级大小齿轮的设计: 112.4传动轴及轴承的设计与校核122.4.1从动轴和轴承的设计与校核12第3章滚齿机滚刀的调整 173.1 Y3150E滚齿机滚刀调整参数173.1.1滚刀的安装与角度调整173.1.2滚刀主轴转速的选择及调整183.1.3轴向进给量的调整193.1.4径向进给滚切蜗轮时机床的调整 203.1.5刀架工作行程挡块位置的调整213.1.6滚刀精加工的调整213.1.7无差动滚削的调整参数223.1.8齿数大于100的质数及整倍数齿轮的调整24结论26谢辞27参考文献28外文资料翻译29The gear processing 29齿轮的加工31前言齿轮是机械产品的重要基础零件,它以其恒功率输出、承载能力大、传动效率高等优点而被广泛应用于机床、汽车、摩托车、农机、建筑机械、工程机械、航空、兵器、工具等领域,其质量、性能、寿命直接影响到各类机械的总成质量。
目前的世界工业形势,不仅使我国滚齿机在数量上急剧增加,而且刺激了滚齿机床向高效及全数控的方向发展,尽可能地减少机床的调整时间,降低工人的劳动强度。
滚齿机是一个调整较复杂的一种机床。
主要涉及到主运动调整、轴向进给运动调整、差动运动调整等,不仅需要计算调整量,而且需要计算调整的方向或是否需搭反向轮及判断调整手柄的位置,需要精通滚齿机的专业技术人员才能完成, 在计算机应用已普及的今天,利用滚齿机调整参数计算系统,来辅助工厂正在生产的普通滚齿机含一、二、三轴简易数控滚齿机的调整,并作为机床附件随机床提供给用户,具有非常现实的应用价值,可以大大降低调整参数计算的技术难度,提高差动挂轮计算的精确度。
必将受到广大滚齿机用户的欢迎。
本文对普通滚齿机设计进行分析,主要进行以下几个方面的研究工作:①分析本论文选题背景,分析滚齿机的使用现状及发展趋势,为论文研究指明方向。
②对 Y3150E滚齿机的结构和传动原理进行分析,结合滚齿原理,说明了滚齿机在滚削不同齿轮时需要调整的各个环节。
③对滚齿机传动系统进行总体设计。
第1章滚齿机概述1.1滚齿机工作原理及滚齿机分类1.1.1滚齿机工作原理图1-1滚切直齿圆柱齿轮的加工原理图普通滚齿机加工原理可用图1-1表示。
根据展成法加工原理,滚刀转一转,工件必须严格地转K/Z转。
其中Z为被加工齿轮的齿数,k为滚刀的头数。
从图2.3中可以看出,必须保证和之间的严格传动比关系,这条传动链简称滚齿的内链。
在图中该内链的传动路线为: -4-5--6-7- 工件。
而形成直线导线的运动则是滚刀架沿工件轴线方向的垂直进给运动,即:工件-7-8-- 9-10-刀架升降丝杆-刀架。
此外滚刀的旋转及调速由主传动链电机-1-2--3-4-,提供。
因而要进行加工圆柱齿轮所需传动链至少有三个链,即一个展成运动内链,两个执行简单运动的外链。
数控滚齿机的加工原理如图1-2所示,其内链与传动比关系仍然遵循展成法加工原理,但其严格的传动比关系不是通过调整机械传动比来实现的,而是通过数控系统的“电子齿轮箱”来保证,从而实现滚齿展成运动。
“ A”“”“”运动分别用单独的伺服电机进行控制,由数控系统进行计算控制来实现滚齿展成加工。
图1-2数控滚齿机的加工原理图1.1.2滚齿机特点(1)适用于成批,小批及单件生产圆柱斜齿轮和蜗轮,尚可滚切一定参数范围的花健轴(2)调整方便,具有自动停车机构(3)具有可靠的安全装置以及自动润滑系统1.1.3滚齿机分类图a立式滚齿机工作台移动图b立式滚齿机立柱移动图c卧式滚齿机图1-3滚齿机的分类滚齿机按布局分为立式和卧式两类。
大中型滚齿机多为立式(图1-3 a[立式滚齿机工作台移动]、图1-3b[立式滚齿机立柱移动),小型滚齿机和专用于加工长的轴齿轮的滚齿机皆为卧式(图1-3c [卧式滚齿机])。
立式滚齿机又分为工作台移动和立柱移动两种。
立式滚齿机工作时,滚刀装在滚刀主轴上,由主电动机驱动作旋转运动,刀架可沿立柱导轧垂直移动,还可绕水平轴线调整一个角度。
工件装在工作台上,由分度蜗轮副带动旋转,与滚刀的运动一起构成展成运动见齿轮加工。
滚切斜齿时,差动机构使工件作相应的附加转动。
工作台或立柱可沿床身导轧移动,以适应不同工件直径和作径向进给。
有的滚齿机的刀架还可沿滚刀轴线方向移动,以便用切向进给法加工蜗轮。
大型滚齿机还设有单齿分度机构、指形铣刀刀架和加工人字齿轮的差动换向机构等。
20世纪60年代以后出现的高效滚齿机,主要采用硬质合金滚刀作高速和大进给量滚齿,滚刀主轴常采用液体静压轴承,能自动处理油雾和排屑。
这种滚齿机适用于齿轮的大量生产。
大型高精度滚齿机主要用来加工对运动平稳性和使用寿命要求很高的齿轮,如汽轮机和船舶推进装置等的大型高精度高速齿轮副。
一般是立式和卧式配套发展。
这种滚齿机除要求严格制造和精细装配调整外,有些还在滚刀主轴和工作台上设置运动误差检测装置,并自动反馈补偿误差,以提高精度。
为避免这种滚齿机受内、外热源的影响,应严格控制液压和冷却系统的温度,还必须安装在恒温厂房内的坚固地基上,并设置防振隔离沟。
小型滚齿机用于加工仪表齿轮。
手表齿轮滚齿机普遍使用硬质合金滚刀加工钟表摆线齿轮,循环节拍快,对机床可靠性要求高,每台机床都配备自动上下料装置进行单机自动加工。
1.2滚齿机的发展趋势滚齿是国内外应用最广的切齿方法,一些国家滚齿机的拥有量约占所有齿轮机床总量的45%- 50 %。
为适应齿轮加工行业对制造精度、生产效率、提高质量及清洁生产的要求,滚齿机及滚齿加工技术出现了以下几个发展趋势:①全数控化所谓的全数控化,指不仅齿轮加工机床的各轴进给运动是数控的,而月.机床的展成运动和差动运动也是数控的,即机床的各运动轴进行CXC 控制及轴间实现联动。