附录A
Lathe fixture design and analysis
Ma 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 lathe fixture design points.
Keywords: lathe fixture; design; points
Lathe 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, 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 fixture
Installed in the fixture on the lathe spindle in addition to three-jaw chuck, four jaw 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 fixture. Common special lathe folder with the following types.
Fixture took disc lathe
This 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 cylindrical 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 accuracy 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
5.56h Φ22.5Φ0.023023+Φ0.023023+Φ180.02±
and positioning the
workpiece with the precision of and
locate the position of dimensional accuracy and 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 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 small errors.
The angle iron fixture
If 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 also ensure that its axis with the axis of the
degree of tolerance for the uranium ; size 5.56h Φ0.0100.00220.5++Φ0.005mm 207H Φ20Φ0.0102.5+Φ0.0110.00510++Φ12Φ10Φ0.02mm 2.5Φ0.0110.00510+
+Φ0.01mm Φ10Φ
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 planes to locate the benchmark.
Installed on the lathe pallet fixture
Limited 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 mounted 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 POINTS
The design features of the positioning device
Lathe fixture positioning device in the design, 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 15.50.1±80.1mm ± 2.5Φ10Φ17.5Φ0.02mm 17.5Φ
axis of spindle rotation. This is described in the previous two sets of lathe fixture when special emphasis. In addition, the positioning device components 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 weight design requirements
Processing 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. Therefore, the lathe fixture between devices should pay attention to the layout of equipment necessary to balance the design weights.
Dlamping device design requirements
Lathe fixture in the course of their work should be the role of centrifugal force and cutting force, the size of its force and direction 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 accuracy of the location positioning device.
Llathe fixture connection with the machine tool spindle design Lathe 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 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 journal 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 order 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 structure
Lathe fixture generally work in the state of the 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 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 the wound and coolant splash and other issues affecting safe operation.
References
140mm (23)D d <-150mm 1.25L D ≤150300mm :0.9L D ≤300mm 0.6L D ≤
[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 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
5.56h Φ22.5Φ0.023023+Φ0.023023+Φ180.02± 5.56h Φ0.0100.00220.5++Φ0.005mm 207H Φ20Φ0.0102.5+Φ0.0110.00510++Φ12Φ10Φ
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。
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。
0.02mm 2.5Φ0.0110.00510++Φ0.01mm Φ10Φ15.50.1±80.1mm ± 2.5Φ10Φ17.5Φ0.02mm 17.5Φ
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。
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］
D 140mm (23)D d <-150mm 1.25L D ≤150300mm :0.9L D ≤300mm 0.6L D ≤
[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）
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附录A Lathe fixture design and analysis Ma 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 lathe fixture design points. Keywords: lathe fixture; design; points Lathe 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, 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 fixture
Manufacturing Engineering and Technology—Machining Serope kalpakjian；Steven R.Schmid 机械工业出版社2004年3月第1版 20.9 MACHINABILITY The machinability of a material usually defined in terms of four factors: 1、Surface finish and integrity of the machined part; 2、Tool life obtained; 3、Force and power requirements; 4、Chip control. Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone. Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below. 20.9.1 Machinability Of Steels Because steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels. Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in
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本科毕业论文(设计) 外文翻译 学院：机电工程学院 专业：机械工程及自动化 姓名：高峰 指导教师：李延胜 2011年05 月10日 教育部办公厅 Failure Analysis，Dimensional Determination And
Analysis，Applications Of Cams INTRODUCTION It is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed．Sometimes a failure can be serious，such as when a tire blows out on an automobile traveling at high speed．On the other hand，a failure may be no more than a nuisance．An example is the loosening of the radiator hose in an automobile cooling system．The consequence of this latter failure is usually the loss of some radiator coolant，a condition that is readily detected and corrected．The type of load a part absorbs is just as significant as the magnitude．Generally speaking，dynamic loads with direction reversals cause greater difficulty than static loads，and therefore，fatigue strength must be considered．Another concern is whether the material is ductile or brittle．For example，brittle materials are considered to be unacceptable where fatigue is involved． Many people mistakingly interpret the word failure to mean the actual breakage of a part．However，a design engineer must consider a broader understanding of what appreciable deformation occurs．A ductile material，however will deform a large amount prior to rupture．Excessive deformation，without fracture，may cause a machine to fail because the deformed part interferes with a moving second part．Therefore，a part fails(even if it has not physically broken)whenever it no longer fulfills its required function．Sometimes failure may be due to abnormal friction or vibration between two mating parts．Failure also may be due to a phenomenon called creep，which is the plastic flow of a material under load at elevated temperatures．In addition，the actual shape of a part may be responsible for failure．For example，stress concentrations due to sudden changes in contour must be taken into account．Evaluation of stress considerations is especially important when there are dynamic loads with direction reversals and the material is not very ductile． In general，the design engineer must consider all possible modes of failure，which include the following． ——Stress ——Deformation ——Wear ——Corrosion ——Vibration ——Environmental damage ——Loosening of fastening devices
毕业设计 外文翻译 题目曲轴的加工工艺及夹具设计学院航海学院 专业轮机工程 学生佟宝诚 学号 10960123 指导教师彭中波 重庆交通大学 2014年
Proceedings of IMECE2008 2008 ASME International Mechanical Engineering Congress and Exposition October 31-November 6, 2008, Boston, Massachusetts, USA IMECE2008-67447 MULTI-OBJECTIVE SYSTEM OPTIMIZATION OF ENGINE CRANKSHAFTS USING AN INTEGRATION APPROACH Albert Albers/IPEK Institute of Product Development University of Karlsruhe Germany Noel Leon/CIDyT Center for Innovation andDesign Monterrey Institute of Technology,Mexico Humberto Aguayo/CIDyT Center forInnovation and Design, Monterrey Institute ofTechnology, Mexico Thomas Maier/IPEK Institute of Product Development University of Karlsruhe Germany ABSTRACT The ever increasing computer capabilities allow faster analysis in the field of Computer Aided Design and Engineering (CAD & CAE). CAD and CAE systems are currently used in Parametric and Structural Optimization to find optimal topologies and shapes of given parts under certain conditions. This paper describes a general strategy to optimize the balance of a crankshaft, using CAD and CAE software integrated with Genetic Algorithms (GAs) via programming in Java. An introduction to the groundings of this strategy is made among different tools used for its implementation. The analyzed crankshaft is modeled in commercial parametric 3D CAD software. CAD is used for evaluating the fitness function (the balance) and to make geometric modifications. CAE is used for evaluating dynamic restrictions (the eigenfrequencies). A Java interface is programmed to link the CAD model to the CAE software and to the genetic algorithms. In order to make geometry modifications to
Int J Interact Des Manuf(2011)5:103–117 DOI10.1007/s12008-011-0119-7 ORIGINAL PAPER Benchmarking of virtual reality performance in mechanics education Maura Mengoni·Michele Germani· Margherita Peruzzini Received:27April2011/Accepted:29April2011/Published online:27May2011 ?Springer-Verlag2011 Abstract The paper explores the potentialities of virtual reality(VR)to improve the learning process of mechanical product design.It is focused on the definition of a proper experimental VR-based set-up whose performance matches mechanical design learning purposes,such as assemblability and tolerances prescription.The method consists of two main activities:VR technologies benchmarking based on sensory feedback and evaluation of how VR tools impact on learning curves.In order to quantify the performance of the technol-ogy,an experimental protocol is de?ned and an testing plan is set.Evaluation parameters are divided into performance and usability metrics to distinguish between the cognitive and technical aspects of the learning process.The experi-mental VR-based set up is tested on students in mechanical engineering through the application of the protocol. Keywords Mechanical product design·Virtual reality·Experimental protocol·Learning curve· Mechanics education 1Introduction Modern society is dominated by continuous scienti?c and technical developments.Specialization has become one of the most important enablers for industrial improvement.As a result,nowadays education is more and more job-oriented and technical education is assuming greater importance.In this context both university and industry are collaborating to create high professional competencies.The?rst disseminates M.Mengoni(B)·M.Germani·M.Peruzzini Department of Mechanical Engineering, Polytechnic University of Marche, Via Brecce Bianche,60131Ancona,Italy e-mail:m.mengoni@univpm.it knowledge and innovative methods while the second pro-vides a practical background for general principles training. The main problem deals with the effort and time required to improve technical learning,while market competitiveness forces companies to demand young and high-quali?ed engi-neers in short time.Therefore,the entire educational process needs to be fast and ef?cient.Novel information technolo-gies(IT)and emerging virtual reality(VR)systems provide a possible answer to the above-mentioned questions.Some of the most important issues,in mechanical design?eld,are the investigation of such technologies potentialities and the evaluation of achievable bene?ts in terms of product design learning effectiveness and quality.While IT has been deeply explored in distance education,i.e.e-learning,VR still rep-resents a novelty. VR refers to an immersive environment that allows pow-erful visualization and direct manipulation of virtual objects. It is widely used for several engineering applications as it provides novel human computer interfaces to interact with digital mock-ups.The close connection between industry and education represents the starting point of this research. Instead of traditional teaching methods,virtual technolo-gies can simultaneously stimulate the senses of vision by providing stereoscopic imaging views and complex spatial effects,of touch,hearing and motion by respectively adopt-ing haptic,sound and motion devices.These can improve the learning process in respect with traditional teaching meth-ods and tools.The observation of students interpreting two-dimensional drawings highlighted several dif?culties:the impact evaluation of geometric and dimensional tolerances chains,the detection of functional and assembly errors,the recognition of right design solutions and the choice of the proper manufacturing operations.These limitations force tutors to seek for innovative technologies able to improve students’perception.