机械毕业设计英文外文翻译71车床夹具设计分析.docx

1、机械毕业设计英文外文翻译71车床夹具设计分析附录ALathe fixture design and analysisMa Feiyue(School of Mechanical Engineering, Hefei, Anhui Hefei 230022, China)Abstract: From the start the main types of lathe fixture, fixture on the flower disc and angle iron clamp lathe was introduced, and on the basis of analysis of a lat

2、he fixture design points.Keywords: lathe fixture; design; pointsLathe for machining parts on the rotating surface, such as the outer cylinder, inner cylinder and so on. Parts in the processing, the fixture can be installed in the lathe with rotary machine with main primary uranium movement. However,

3、 in order to expand the use of lathe, the work piece can also be installed in the lathe of the pallet, tool mounted on the spindle.THE MAIN TYPES OF LATHE FIXTURE Installed on the lathe spindle on the lathe fixtureInstalled in the fixture on the lathe spindle in addition to three-jaw chuck, four jaw

4、 chuck, faceplate, front and rear dial with heart-shaped thimble and a combination of general-purpose lathe fixture folder outside (as these fixtures have been standardized and machine tool accessories, can be purchased when needed do not have to re-design), usually need to design special lathe fixt

5、ure. Common special lathe folder with the following types.Fixture took disc latheThis process is to find the generic is installed on the faceplate is difficult to ensure the accuracy of the workpiece, so the need to design special lathe fixture. The lathe fixture design process, first select the cyl

6、indrical workpiece and the end cylinder B, the semi-circular surface finishing (finishing second circular surface when the car has been good with circular surface) is positioned datum, limit of six degrees of freedom, in line with the principle of base overlap.The work piece fixture to ensure the ac

7、curacy of measures:The workpiece fixture to ensure the accuracy of measures:(1) tool by the workpiece machining position relative to the guarantee. (2) symmetry of size 0.02. Rely on sets of holes and positioning theworkpiece with the precision of and locate the position of dimensional accuracy and

8、process specification requirements to ensure that the same parts of the four circular surface must be processed on the same pins.(3) all fixtures and clip bushing hole axis vertical concrete face A tolerance of .because the A side is the fixture with the lathe when the transition assembly base plate

9、 installed.(4) specific folder on the -hole plate with the transition to the benchmarks pin design requires processing each batch of parts to be sold in the transitional disk with a coat made of a tight match, and the local processing of the face plate to reduce the transition fixture on the set of

10、small errors.The angle iron fixtureIf the processing technology for the and , drilling, boring, reaming process scheme. Boring is required in the face A face of finishing B ( range) and the A, B sides and the hole axis face runout does not exceed . In addition, the processing of -hole, you should al

11、so ensure that its axis with the axis of the degree of tolerance for the uranium ; size and the location of ; and and of the axis of the axis of displacement tolerance not more than .Based on the above analysis on the part of process size, choose the -hole on the workpiece surface and M, N two plane

12、s to locate the benchmark.Installed on the lathe pallet fixtureLimited equipment in the factory, similar to the shape of the parts box, its small size, designed for easy installation without turning the main pumping in the fixture, you can drag the panel removal tool holder, fixture and workpiece mo

13、unted on the pallet. Processing, mounted on the lathe tool on the main primary uranium movement, feed the work piece for movement, so you can expand the scope of application of lathe.LATHE FIXTURE DESIGN POINTSThe design features of the positioning deviceLathe fixture positioning device in the desig

14、n, in addition to considering the limited degrees of freedom, the most important thing is to make the surface of the workpiece axis coincides with the axis of spindle rotation. This is described in the previous two sets of lathe fixture when special emphasis. In addition, the positioning device comp

15、onents in the specific folder location on the workpiece surface accuracy and dimensional accuracy of the location has a direct relationship, so the total figure on the fixture, be sure to mark the location positioning device dimensions and tolerances, and acceptance as a fixture conditions.Jig weigh

16、t design requirementsProcessing in the lathe, the workpiece rotation together with the fixture will be a great centrifugal force and the centrifugal force increases sharply with increasing speed. This precision machining, processing, and the vibration would affect the surface quality of parts. There

17、fore, the lathe fixture between devices should pay attention to the layout of equipment necessary to balance the design weights.Dlamping device design requirementsLathe fixture in the course of their work should be the role of centrifugal force and cutting force, the size of its force and direction

18、of the workpiece position relative to the base is changing. Therefore, a sufficient clamping device clamping force and a good self-locking. To ensure safe and reliable clamping. However, the clamping force can not be too large, and require a reasonable layout of the force, and will not undermine the

19、 accuracy of the location positioning device.Llathe fixture connection with the machine tool spindle designLathe fixture connected with the spindle directly affects the accuracy of the rotary fixture accuracy, resulting in errors in the workpiece. Therefore, the required fixture rotation axis lathe

20、spindle axis with high concentricity.Lathe fixture connected with the spindle structure, depending on the spindle when turning the front of the structure model is confirmed, by machine instructions or the manual check on. Lathe spindle nose are generally outside the car with cone and cone, or a jour

21、nal and other structures with the flange end connections to the fixture base. Note, however, check the manual should be used with caution, because many manufacturers of machine tools, machine tools of similar size may differ. The most reliable method for determining, or to field measurements in orde

22、r to avoid errors or losses.Determine the fixture and the spindle connecting structure, generally based on fixture size of the size of the radial: radial dimension less than , or small lathe fixture.Pairs of fixture requirements of the overall structureLathe fixture generally work in the state of th

23、e cantilever in order to ensure process stability, compact fixture structure should be simple, lightweight and safe, overhang length to as small as possible, the center of gravity close to the front spindle bearing. Fixture overhang length L and the ratio of outer diameter D profile can refer to the

24、 following values used:Less than the diameter D in fixture, ; Diameter D between the fixture in , ; Fixture diameter D is greater than , .To ensure security, installed in the specific folder on the components of the folder is not allowed out beyond the specific diameter, should also consider cutting

25、 the wound and coolant splash and other issues affecting safe operation.References 1 Chen Guofu. Lathe fixture J. Mechanical workers. Cold, 2000 (12)2 Dong Yuming. Yang Hongyu. Fixture design in the common problems J. Mechanical workers. Cold, 2005 (1) 3 Liu Juncheng The machine clamps the clamping

26、force in the design process calculations J. tool technology, 2007 (6)附录B车床夹具设计分析 （合肥学院机械工程系，安徽 合肥 230022）摘 要：从车床夹具的主要类型着手，对花盘式车床夹具和角铁式夹具进行了介绍，并在此基础上分析了车床夹具设计要点。关键词：车床夹具；设计；要点 车床主要用于加工零件上的回转表面，如外圆柱面、内圆柱面等。零件在加工时，可安装在车床夹具上同机床主铀一起回转作主运动。但为扩大车床的使用范围，也可将工件安装在车床的拖板上，刀具装在主轴上。1 车床夹具的主要类型1.1 安装在车床主轴上的车床夹具 安装

27、在车床主轴上的夹具除三爪卡盘、四爪卡盘、花盘、前后顶针以及拨盘与鸡心夹的组合通用车床夹具外（这些夹具现已标准化并作为机床附件，需用时可购买不必重新设计)，通常还需设计专用车床夹具。常见的专用车床夹具有以下几种类型1.1.1 花盘式车床夹具 这道工序若要在通用花盘上找正安装是难以保证工件精度要求的，所以需要设计专用车床夹具。设计该工序的车床夹具，首先选定工件外圆柱面与端面B、半精车的圆弧面（精车第二个圆弧面时则用已经车好的圆弧面）为定位基准面、限制了6个自由度，符合基准重合原则。 该夹具保证工件加工精度的措施有： （1）靠工件相对于刀具的加工位置保证。 （2）尺寸对称度0.02。依靠定位套孔与工

28、件的配合精度与定位的位置尺寸精度来保证且工艺规程要求同一工件的4个圆弧面必须在同一定位销上进行加工。 （3）夹具的所有衬套孔的轴线与夹具体的端面A垂直度公差为因为A面是夹具与车床过渡盘安装时的装配基准。 （4）夹具体上孔为与过渡盘上销的对定基准，设计要求每批零件加工时都要在过渡盘上装销配作成较紧的配合,且就地加工过渡盘端面以减小夹具的对定误差。1.1.2 角铁式夹具 若加工和的工艺为钻、镗、铰的工艺方案。在镗孔时需精车端面A端面B （范围内） 且A、B两面与孔 轴线的端面跳动量不超过。此外，加工孔时，还应保证其轴线与 轴线的同铀度允差为； 的位置尺寸为和；和的轴线与的轴线位移度公差不得大于。

29、根据以上对零件工序尺寸的分析，选工件上的孔表面和M、N两个平面为定位基准。1.1.3 安装在车床拖板上的夹具 在工厂设备有限时，类似箱体形状的零件，其尺寸较小，不便于设计成安装在车床主抽上的夹具，可以将拖板上的刀架拆除，夹具和工件安装在拖板上。加工时，装在车床主铀上的刀具作主运动，工件作进给运动，这样可以扩大车床的应用范围。2 车床夹具设计要点2.1 定位装置的设计要点 车床夹具在设计定位装置时，除考虑应限制的自由度外，最重要的是要使工件加工表面的轴线与机床主轴回转轴线重合。这一点在前面介绍两套车床夹具时已特别强调了。除此之外，定位装置的元件在夹具体上的位置精度与工件加工表面的位置尺寸精度有直

30、接的关系，所以夹具总图上，一定要标注定位元件的位置尺寸和公差，作为夹具的验收条件之一。2.2 夹具配重的设计要求 在车床上进行加工时、工件随夹具一起转动，将受到很大的离心力的作用，且离心力随转速的增高而急剧增大。这对零件的加工精度、加工过程中的振动以及零件的表面质量都会有影响。所以，车床夹具要注意备装置之间的布局，必要时设计配重块加以平衡。2.3 夹紧装置的设计要求 车床夹具在工作过程中要受到离心力和切削力的作用，其合力的大小与方向相对于工件的定位基准又是变化的。所以夹紧装置要有足够的夹紧力和良好的自锁性。以保证夹紧安全可靠。但夹紧力不能过大、且要求受力布局合理，不至于破坏定位装置的位置精度。

31、2.4 车床夹具与机床主轴的连接设计要求车床夹具与主轴的连接精度直接影响到夹具的回转精度，从而造成工件的误差。因此，要求夹具的回转轴线与车床主轴回转轴线具有较高的同轴度。车床夹具与机床主轴相连接的结构形式，取决于机床主轴前端的结构形式 当车床型号确定后，可由机床使用说明书或有关手册查知。车床主轴前端一般都车有锥孔和外锥，或轴颈与凸缘端面等结构提供给夹具的连接基准。但要注意，查手册时要谨慎使用，因机床生产厂家很多，同类机床的尺寸可能有差异。最可靠的确定方法，还是去现场测量，以免造成错误或损失。确定夹具与机床主轴连接结构，一般是根据夹具径向尺寸的大小而定：径向尺寸小于，或的小型车床夹具2.5 对夹具总体结构的要求车床夹具一般都是在悬臂状态下工作的，为保证加工过程的稳定性，夹具结构应力求简单紧凑，轻便且安全，悬伸长度要尽量小，重心靠近主轴前支承。夹具悬伸长度L与外廓直径D之比可参考以下的数值选用：直径D在以内的夹具，；直径D在间的夹具，；直径D大于的夹具，。为保证安全，装在夹具体上的各个元件不允许伸出夹具体直径之外，此外还应考虑切削的缠绕与冷却液的飞溅等影响安全操作的问题。参考文献1 陈国甫.车床夹具J.机械工人.冷加工，2000(12)2 董玉明.杨洪玉.夹具设计中常见的问题J.机械工人.冷加工，2005（1）3 刘俊成.机床夹具在设计过程中夹紧力的计算J.工具技术，2007（6）