二级圆柱齿轮减速器及镗孔工序夹具设计（含CAD图纸+文档）
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外文资料
Introduction of Machining Process
As a method of shape generation, mechanical processing is the most common and important method in all manufacturing processes. Machining process is a process of generating shape. In this process, the driving device makes some materials on the workpiece be removed in the form of chips. Although in some cases, the workpiece can not bear the situation, the use of mobile equipment to achieve processing, but most of the mechanical processing is through both supporting the workpiece and supporting tool equipment to complete. There are two aspects in the process of knowledge processing. Small batch production costs less. For casting, forging and pressure processing, every specific shape of the workpiece to be produced, even a part, almost costs a lot of processing costs. The structural shape produced by welding depends to a large extent on the form of effective raw materials. Generally speaking, through the use of valuable equipment without special processing conditions, almost any kind of raw materials can be started, with the aid of mechanical processing to process raw materials into any required structural shape, as long as the external size is large enough, that is possible. Therefore, for the production of a part, even when the structure of the part and the batch size to be produced are suitable for casting, forging or pressure processing, but usually mechanical processing is preferred. Rigorous accuracy and good surface finish, the second use of mechanical processing is based on high accuracy and possible surface finish. Many parts, if produced in large quantities by other means, are produced in small quantities with low tolerances and satisfying requirements in mechanical processing. On the other hand, many parts improve their general surface shape by rough processing technology, but only in the need for high precision and selected surface to be machined. For example, the internal thread, in addition to mechanical processing, almost no other processing methods can be processed. If the forged workpiece on the small hole processing, is also forged immediately after the completion of mechanical processing.
1.Basic Machining Parameters
The basic relationship between workpiece and tool in cutting is fully described by the following four factors: the geometry of tool, cutting speed, feed speed and back feed. Cutting tools must be made of a suitable material. They must be strong, tough, hard and wear-resistant. The geometric shape of the tool is characterized by the plane of the tool tip and the angle of the tool. It must be correct for every cutting process. Cutting speed is the rate at which the cutting edge passes through the surface of the workpiece. It is expressed in inches per minute. In order to process effectively, the cutting speed must be adapted to the matching of specific workpiece and cutting tool. Generally speaking, the harder the workpiece material is, the lower the speed is. Feed speed is the speed at which the tool cuts into the workpiece. If the workpiece or tool rotates, the feed is measured in inches per turn. When the cutter or workpiece moves back and forth, the feed is measured in inches per stroke. Generally speaking, when other conditions are the same, the feed rate is inversely proportional to the cutting speed. Back feed is measured in inches as the distance the tool enters the workpiece. It is equal to the chip width in rotary cutting or the chip thickness in linear cutting. Rough processing is deeper than finishing.
2.Tool Wear
From the numerous brittle cracks and edge cracks that have been treated, there are basically three types of tool wear: flank wear, rake wear and V-notch wear. The wear of flank occurs on both the main blade and the auxiliary blade. As for the main cutting edge, because it undertakes the task of cutting most metal chips, it leads to increasing cutting force and increasing cutting temperature. If it is left unchecked, it may lead to vibration of the tool and workpiece and the condition of effective cutting may no longer exist. As for the auxiliary blade, it determines the size and surface finish of the workpiece. The wear of the flank may result in substandard products and poor surface finish. Under most actual cutting conditions, the tool will be effective when the wear of the main rake face is larger than that of the secondary rake face, resulting in unqualified parts. Because of the uneven distribution of stress on the tool surface, the stress in the sliding contact area between the chip and the front tool face is the largest at the beginning of the sliding contact area, while it is zero at the end of the contact area, so abrasive wear occurs in this area. This is because there is more serious wear near the cutting block than near the blade, and the wear near the blade is lighter due to the loss of contact between the chip and the rake face. This results in pitting on the rake face at a certain distance from the cutting edge, which is usually considered as wear on the rake face. Usually, the wear cross section is circular. In many cases and for actual cutting conditions, the wear of rake face is lighter than that of flank face, so the wear of flank face is more commonly used as the scale sign of tool failure. However, as many authors have indicated, the temperature on the rake face rises faster than that on the flank face with increasing cutting speed, and the wear rate in any form is essentially affected by temperature changes. Therefore, the wear of rake face usually occurs in high-speed cutting. The tail of the main flank wear belt of the tool is in contact with the surface of the unprocessed workpiece, so the flank wear is more obvious than along the end of the wear belt, which is the most common. This is due to the local effect, which is like the hardened layer on the unprocessed surface. This effect is caused by the hardening of the workpiece caused by the previous cutting. Not only cutting, but also local high temperature produced by the blade, such as oxide skin, can cause this effect. This kind of local wear is usually called pitting wear and is occasionally very serious. Although the appearance of concave pits has no substantial impact on the cutting properties of the tool, the concave pits often deepen gradually. If the cutting continues, the tool will be in danger of fracture. If any progressive form of wear is allowed to continue to develop, the ultimate wear rate will increase significantly and the tool will have destructive failure damage, that is, the tool will no longer be used for cutting, resulting in the scrap of the workpiece, that is good, serious machine tool damage can be caused. For all kinds of cemented carbide tools and for all kinds of wear, it is considered that the end of tool life cycle has been reached before serious failure occurs. However, for all kinds of high-speed steel tools, the wear is non-uniform. It has been found that when the wear permits continuous or even serious failure, the most significant thing is that the tool can be used for regrinding. Of course, in practice, the cutting time is much shorter than the time when the tool is used for failure. One of the following phenomena is the characteristic of the beginning of tool failure: the most common is the sudden increase of cutting force, the serious increase of burnout rings and noise on the workpiece, etc.
3. The influence of cutting parameters on cutting temperature
In metal cutting operation, heat occurs in the main deformation zone and the secondary deformation zone. This results in complex temperature distributions throughout cutters, workpieces and chips. The figure shows a set of typical isothermal curves, from which it can be seen that, as can be expected, when the workpiece material is cut in the main deformation zone, there is a large temperature gradient along the whole chip width, while in the sub-deformation zone, when the chip is cut off, there is a higher temperature on the rake face near the chip. This results in higher cutting temperature near the cutting edge of the rake face and chips. In essence, because all the functions in metal cutting are converted into heat, it can be predicted that these factors, which consume Zeng's unit volume power of the cut metal, will increase the cutting temperature. When the rake angle of the tool increases and all other parameters remain unchanged, the power consumption per unit volume of the cutting metal will be reduced, and the cutting temperature will also be reduced. This situation is even more complicated when considering the increase of undeformed chip thickness and cutting speed. The increasing trend of undeformed chip thickness will lead to a proportional effect on the total heat passing through the workpiece. Tools and chips still maintain a fixed proportion, while the change of cutting temperature tends to decrease. However, with the increase of cutting speed, the amount of heat transferred to the workpiece decreases, which in turn increases the chip temperature rise in the main deformation zone. Furthermore, the sub-deformation zone is bound to be smaller, which will have a warming effect in this area. The change of other cutting parameters has no effect on the unit volume consumption of the cut, so it has no effect on the cutting temperature in fact. Because facts have shown that even a small change in cutting temperature will have a substantial impact on tool wear rate. This shows that it is appropriate to determine the cutting temperature from the cutting parameters. The most direct and accurate method for measuring the temperature of HSS cutters is the Wright-Trent method, which provides detailed information on the temperature distribution of HSS cutters. This technology is based on the metallographic microscopic measurement of high-speed steel tool cross-section. The aim is to establish the relationship between the microstructural change and the thermal change law. Wright has discussed the method of measuring cutting temperature and temperature distribution of HSS tools when processing a wide range of workpiece materials. This technology has been further developed by using electron microscopic scanning technology. The purpose of this technology is to study the microstructural changes caused by tempering high-speed steels with various martensitic structures. This technique is also used to study the temperature distribution of single point turning tools and twist drills for high speed steel.
4. Design of Automatic Fixture
The traditional synchronous fixture used for assembling equipment moves the parts to the center of the fixture to ensure that the parts are removed from the conveyor or from the device disc and placed on the positioned position. However, in some applications, forcing parts to move to the central line may cause parts or equipment damage. When parts are fragile and small vibration may lead to scrap, or when the position is specified by the spindle or die of the machine tool, or when the tolerance requirements are very precise, it is preferable to let the fixture adapt to the position of the parts, rather than vice versa. For these tasks, Zaytran, Elyria, Ohio, USA, has developed asynchronous Western-type flexibility fixtures for general functional data. Because the clamp force and synchronization device are independent, the synchronization device can be replaced by a precise sliding device without affecting the clamp force. Fixture specifications range from 0.2 inch stroke, 5 pound clamping force to 6 inch stroke, 400 inch clamping force. The characteristic of modern production is that the batch size is becoming smaller and smaller, and the product specifications change most. Therefore, in the final stage of production, assembly is particularly vulnerable due to changes in production plans, batches and product designs. This situation is forcing many companies to devote more efforts to extensive rationalization reforms and assembly automation as mentioned earlier. Although the development of flexible fixture is lagging behind the development of flexible transportation processing equipment, such as industrial robots, it is still trying to increase the flexibility of fixture. In fact, the special investment of production equipment, an important fixture device, strengthens the economic support of making fixture more flexible. According to their flexibility, fixtures can be divided into: special fixtures, modular fixtures, standard fixtures, high flexible fixtures. Flexible fixtures are characterized by their high adaptability to different workpieces and low cost of replacement. Flexible fixtures with changeable structural forms are equipped with parts with changeable structural arrangements (such as needle-shaped buccal plates, multi-piece parts and sheet-shaped buccal plates), non-special clamping or clamping elements for standard workpieces (such as starting standard clamping fixtures and fixture fittings with movable components), or ceramic or hardened intermediates (such as flow particle bed fixtures and thermal fixtures). Tighten clamp. In order to produce, parts need to be tightened in fixtures. There are several steps which have nothing to do with the flexibility of fixtures. According to the part processed, i.e. the basic part and the working characteristics, the required position of the workpiece in the fixture is determined. Then the combination of several stable planes must be selected. These stable planes constitute the clamping of the workpiece fixed in the fixture to determine its position. The shape contour structure balances all forces and moments, and ensures that it is close to the working characteristics of the workpiece. Finally, it is necessary to calculate, adjust and assemble the required positions of dismountable or standard fixture elements so that the workpiece can be firmly clamped in the fixture. According to this program, the contour structure and assembly planning and recording process of fixture can be controlled automatically. The task of structural modeling is to produce a combination of several stable planes, so that the clamping forces on these planes will stabilize the workpiece and fixture. Traditionally, this task can be accomplished in a man-machine conversation, which is almost fully automated. One-man-machine conversation, that is to say, the advantage of automatic fixture structure modeling is that it can organize and plan fixture design, reduce the required designers, shorten the research cycle and better configure working conditions. In short, it can successfully improve the production efficiency and efficiency of fixture. With the full preparation of the construction scheme and a batch of materials, the first assembly can successfully save up to 60% of the time.
The use of automatic fixture can reduce manpower and facilitate rhythmic production. The use of automatic fixtures instead of people to work, this is a direct reduction of manpower - one side, together because the use of automatic fixtures can be connected to the work, this is another side of reducing manpower. Therefore, in the inductive processing active line of automated machine tools, there is no automatic fixture at present, in order to reduce manpower and more precise control of the production rhythm, so as to facilitate the rhythmic operation of production.
The use of automatic fixture is conducive to the degree of initiative in data transmission, workpiece loading and unloading, tool replacement and machine installation, and then can improve labor productivity and reduce production costs.
中文译文
机械加工过程介绍
作为产生形状的一种加工方法，机械加工是所有制造过程中最普遍使用的而且是最重要的方法。机械加工过程是一个产生形状的过程，在这过程中，驱动装置使工件上的一些材料以切屑的形式被去除。尽管在某些场合，工件无承受的情况下，使用移动式装备来实现加工，但大多数的机械加工是通过既支承工件又支承刀具的装备来完成。加工知识的过程有两个方面。小批生产低费用。对于铸造、锻造和压力加工，每一个要生产的具体工件形状，即使是一个零件，几乎都要花费高额的加工费用。靠焊接来产生的结构形状，在很大程度上取决于有效的原材料的形式。一般来说，通过利用贵重设备而又无需特种加工条件下，几乎可以以任何种类原材料开始，借助机械加工把原材料加工成任意所需要的结构形状，只要外部尺寸足够大，那都是可能的。因此对于生产一个零件，甚至当零件结构及要生产的批量大小上按原来都适于用铸造、锻造或者压力加工来生产的，但通常宁可选择机械加工。严密的精度和良好的表面光洁度，机械加工的第二方面用途是建立在高精度和可能的表面光洁度基础上。许多零件，如果用别的其他方法来生产属于大批量生产的话，那么在机械加工中则是属于低公差且又能满足要求的小批量生产了。另方面，许多零件靠较粗的生产加工工艺提高其一般表面形状，而仅仅是在需要高精度的且选择过的表面才进行机械加工。例如内螺纹，除了机械加工之外，几乎没有别的加工方法能进行加工。又如已锻工件上的小孔加工，也是被锻后紧接着进行机械加工才完成的。
1 基本的机械加工参数
切削中工件与刀具的基本关系是以以下四个要素来充分描述的：刀具的几何形状，切削速度，进给速度，和背吃刀量。切削刀具必须用一种合适的材料来制造，它必须是强固、韧性好、坚硬而且耐磨的。刀具的几何形状以刀尖平面和刀具角为特征，对于每一种切削工艺都必须是正确的。切削速度是切削刃通过工件表面的速率，它是以每分钟英寸来表示。为了有效地加工，切削速度高低必须适应特定的工件与刀具配合。一般来说，工件材料越硬，速度越低。进给速度是刀具切进工件的速度。若工件或刀具作旋转运动，进给量是以每转转过的英寸数目来度量的。当刀具或工件作往复运动时，进给量是以每一行程走过的英寸数度量的。一般来说，在其他条件相同时，进给量与切削速度成反比。背吃刀量以英寸计是刀具进入工件的距离。它等于旋削中的切屑宽度或者等于线性切削中的切屑的厚度。粗加工比起精加工来，吃刀深度较深。
2 刀具磨损
从已经被处理过的无数脆裂和刃口裂纹的刀具中可知，刀具磨损基本上有三种形式：后刀面磨损，前刀面磨损和V型凹口磨损。后刀面磨损既发生在主刀刃上也发生副刀刃上。关于主刀刃，因其担负切除大部金属切屑任务，这就导致增加切削力和提高切削温度，如果听任而不加以检查处理，那可能导致刀具和工件发生振动且使有效切削的条件可能不再存在。关于副刀刃，那是决定着工件的尺寸和表面光洁度的，后刀面磨损可能造成尺寸不合格的产品而且表面光洁度也差。在大多数实际切削条件下，由于主前刀面先于副前刀面磨损，磨损到达足够大时，刀具将实效，结果是制成不合格零件。由于刀具表面上的应力分布不均匀，切屑和前刀面之间滑动接触区应力，在滑动接触区的起始处最大，而在接触区的尾部为零，这样磨蚀性磨损在这个区域发生了。这是因为在切削卡住区附近比刀刃附近发生更严重的磨损，而刀刃附近因切屑与前刀面失去接触而磨损较轻。这结果离切削刃一定距离处的前刀面上形成麻点凹坑，这些通常被认为是前刀面的磨损。通常情况下，这磨损横断面是圆弧形的。在许多情况中和对于实际的切削状况而言，前刀面磨损比起后刀面磨损要轻，因此后刀面磨损更普遍地作为刀具失效的尺度标志。然而因许多作者已经表示过的那样在增加切削速度情况下，前刀面上的温度比后刀面上的温度升得更快，而且又因任何形式的磨损率实质上是受到温度变化的重大影响。因此前刀面的磨损通常在高速切削时发生的。刀具的主后刀面磨损带的尾部是跟未加工过的工件表面相接触，因此后刀面磨损比沿着磨损带末端处更为明显，那是最普通的。这是因为局部效应，这像未加工表面上的已硬化层，这效应是由前面的切削引起的工件硬化造成的。不只是切削，还有像氧化皮，刀刃产生的局部高温也都会引起这种效应。这种局部磨损通常称作为凹坑性磨损，而且偶尔是非常严重的。尽管凹坑的出现对刀具的切削性质无实质意义的影响，但凹坑常常逐渐变深，如果切削在继续进行的话，那么刀具就存在断裂的危机。如果任何进行性形式的磨损任由继续发展，最终磨损速率明显地增加而刀具将会有摧毁性失效破坏，即刀具将不能再用作切削，造成工件报废，那算是好的，严重的可造成机床破坏。对于各种硬质合金刀具和对于各种类型的磨损，在发生严重失效前，就认为已达到刀具的使用寿命周期的终点。然而对于各种高速钢刀具，其磨损是属于非均匀性磨损，已经发现：当其磨损允许连续甚至到严重失效开始，最有意义的是该刀具可以获得重磨使用，当然，在实际上，切削时间远比使用到失效的时间短。以下几种现象之一均是刀具严重失效开始的特征：最普遍的是切削力突然增加，在工件上出现烧损环纹和噪音严重增加等。
3 切削参数的改变对切削温度的影响
金属切削操作中，热是在主变形区和副变形区发生的。这结果导致复杂的温度分布遍及刀具、工件和切屑。图中显示了一组典型等温曲线，从中可以看出：像所能预料的那样，当工件材料在主变形区被切削时，沿着整个切屑的宽度上有着很大的温度梯度，而当在副变形区，切屑被切落时，切屑附近的前刀面上就有更高的温度。这导致了前刀面和切屑离切削刃很近的地方切削温度较高。实质上由于在金属切削中所做的全部功能都被转化为热，那就可以预料：被切离金属的单位体积功率消耗曾家的这些因素就将使切削温度升高。这样刀具前角的增加而所有其他参数不变时，将使切离金属的单位体积所耗功率减小，因而切削温度也将降低。当考虑到未变形切屑厚度增加和切削速度，这情形就更是复杂。未变形切屑厚度的增加趋势必导致通过工件的热的总数上产生比例效应，刀具和切屑仍保持着固定的比例，而切削温度变化倾向于降低。然而切削速度的增加，传导到工件上的热的数量减少而这又增加主变形区中的切屑温升。进而副变形区势必更小，这将在该区内产生升温效应。其他切削参数的变化，实质上对于被切离的单位体积消耗上并没有什么影响，因此实际上对切削温度没有什么作用。因为事实已经表明：切削温度即使有小小的变化对刀具磨损率都将有实质意义的影响作用。这表明如何人从切削参数来确定切削温度那是很合适的。测定高速钢刀具温度的最直接和最精确的方法是莱特＆特伦特法，这方法也就是可提供高速钢刀具温度分布的详细信息的方法。该项技术是建立在高速钢刀具截面金相显微测试基础上，目的是要建立显微结构变化与热变化规律图线关系式。当要加工广泛的工件材料时，莱特已经论述过测定高速钢刀具的切削温度及温度分布的方法。这项技术由于利用电子显微扫描技术已经进一步发展，目的是要研究将已回过火和各种马氏体结构的高速钢再回火引起的微观显微结构变化情况。这项技术亦用于研究高速钢单点车刀和麻花钻的温度分布。
4 自动夹具设计
用做装配设备的传统同步夹具把零件移动到夹具中心上，以确保零件从传送机上或从设备盘上取出后置于已定位置上。然而在某些应用场合、强制零件移动到中心线上时，可能引起零件或设备破坏。当零件易损而且小小振动可能导致报废时，或当其位置是由机床主轴或模具来具体时，再或者当公差要求很精密时，那宁可让夹具去适应零件位置，而不是相反。为着这些工作任务，美国俄亥俄州Elyria的Zaytran公司已经开发了一般性功能数据的非同步西类柔顺性夹具。因为夹具作用力和同步化装置是各自独立的，该同步装置可以用精密的滑移装置来替换而不影响夹具作用力。夹具规格范围是从0.2英寸行程，5英镑夹紧力到6英寸行程、400英寸夹紧力。现代生产的特征是批量变得越来越小而产品的各种规格变化最大。因此，生产的最后阶段，装配因生产计划、批量和产品设计的变更而显得特别脆弱。这种情形正迫使许多公司更多地致力于广泛的合理化改革和前面提到过情况那样装配自动化。尽管柔性夹具的发展很快落后与柔性运输处理装置的发展，如落后于工业机器人的发展，但仍然试图指望增加夹具的柔顺性。事实上夹具的重要的装置——生产装置的专向投资就加强了使夹具更加柔性化在经济上的支持。根据它们柔顺性，夹具可以分为：专用夹具、组合夹具、标准夹具、高柔性夹具。柔性夹具是以它们对不同工件的高适应性和以少更换低费用为特征的。结构形式可变换的柔性夹具装有可变更结构排列的零件（例如针形颊板，多片式零件和片状颊板），标准工件的非专用夹持或夹紧元件（例如：启动标准夹持夹具和带有可移动元件的夹具配套件），或者装有陶瓷或硬化了的中介物质（如：流动粒子床夹具和热夹具紧夹具）。为了生产，零件要在夹具中被紧固，需要产生夹紧作用，其有几个与夹具柔顺性无关的步骤：根据被加工的即基础的部分和工作特点，确定工件在夹具中的所需的位置，接着必须选择若干稳定平面的组合，这些稳定平面就构成工件被固定在夹具中确定位置上的夹持状轮廓结构，均衡所有各力和力矩，而且保证接近工件工作特点。最后，必须计算、调整、组装可拆装的或标准夹具元件的所需位置，以便使工件牢牢地被夹紧在夹具中。依据这样的程序，夹具的轮廓结构和装合的规划和记录过程可以进行自动化控制。 结构造型任务就是要产生若干稳定平面的组合，这样在这些平面上的各夹紧力将使工件和夹具稳定。按惯例，这个任务可用人—机对话即几乎完全自动化的方式来完成。一人—机对话即以自动化方式确定夹具结构造型的优点是可以有组织有规划进行夹具设计，减少所需的设计人员，缩短研究周期和能更好地配置工作条件。简言之，可成功地达到显著提高夹具生产效率和效益。在充分准备了构造方案和一批材料情况下，在完成首次组装可以成功实现节约时间达60%。
自动夹具的使用能够减轻人力，并便于有节奏的出产。使用自动夹具代替人进行作业，这是直接削减人力的-个旁边面，一起因为使用自动夹具能够接连的作业，这是削减人力的另一个旁边面。因而，在主动化机床的归纳加工主动线上，当前简直都没有自动夹具，以削减人力和更精准的操控出产的节拍，便于有节奏的进行作业出产。
使用自动夹具有利于完成资料的传送、工件的装卸、刀具的替换以及机器的安装等的主动化的程
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