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活塞环铣开口夹具设计与装配工艺规划36页 14000字数+说明书+开题报告+中期报告+4张CAD图纸中期.doc外文翻译-基于事例推理的夹具设计研究与应用.doc套筒.dwg对刀块.dwg弹簧.dwg总装配图.dwg活塞环铣开口夹具设计与装配工艺规划开题报告.doc活塞环铣开口夹具设计与装配工艺规划论文.doc摘要本次设计内容涉及了机械制造工艺及机床夹具设计、金属切削机床、公差配合与测量等多方面的知识。活塞环加工工艺规程及夹具设计是包括零件加工的工艺设计、工序设计以及专用夹具的设计三部分。在工艺设计中要首先对零件进行分析，了解零件的工艺再设计出毛坯的结构，并选择好零件的加工基准，设计出零件的工艺路线；接着对零件各个工步的工序进行尺寸计算，关键是决定出各个工序的工艺装备及切削用量；然后进行专用夹具的设计，选择设计出夹具的各个组成部件，如定位元件、夹紧元件、引导元件、夹具体与机床的连接部件以及其它部件；计算出夹具定位时产生的定位误差，分析夹具结构的合理性与不足之处，并在以后设计中注意改进。关键词：工序、夹紧、定位。目录1 绪论11.1 机床夹具介绍11 .2夹具的现状及生产对其提出新的要求11.3 现代夹具的发展方向21.4本文主要研究内容42 活塞铣开口夹具形式的选择及原理的确定52.1活塞铣开口夹具的性能确定52.1.1活塞铣开口夹具结构设计原则52.2 活塞铣开口夹具的原理确定52.2 研究方案：53 活塞铣开口夹具主要零部件的结构设计93.1装置零件的结构设计93.2定向键与对刀装置设计103.3夹紧装置设计123.4夹具体零件设计144 活塞铣开口夹具的计算分析164.1活塞环铣开口零件工艺分析164.2活塞环铣开口零件定位分析164.3活塞环铣开口夹具切削力和夹紧力的计算164.4活塞环铣开口夹具定位误差分析185 活塞铣开口夹具的装配工艺设计与仿真195.1装配的基本概念195.2活塞铣开口夹具的装配205.3活塞铣开口夹具的装配工艺规划215.3.1活塞铣开口夹具装配流程215.3.2装配工艺过程215.4装配运动仿真235.4.1装配仿真的概念235.4.2产品装配仿真的实现245.4.3装配后操作245.5活塞铣开口夹具的运动演示256 总结27参考文献28致谢30毕业设计（论文）知识产权声明31毕业设计（论文）独创性声明32 所谓机床夹具，是指用来装夹工件，使工件固定在机床上，利于加工成标准件的一种装置。机床夹具作为机械制造业中不可或缺的重要环节，对整个机械制造业的水平提升有着极其蕈要的影响，甚至有些时候是关键性的影响。如果要实现机械制造的现代化，必须首先提高机床夹具的现代化水平，提高机床灾具的制造效率，实现机床灾具的标准化。然而，传统的机床夹具还占据着机械制造业的绝对主导地位，这成为了机械制造业的现代化进程的障碍因素。由于机床灾具的优劣，决定着机电产品标准件的质量和制作精度，机床夹具设计对机电产品的质量有着非常重要的现实意义，随着机械制造领域理论研究的日益深入，机床夹具的设计必将迎来充分发展的时期。机床夹具在机电产品制造中是必不可少的工具，机床夹具设计的效果直接决定着机电产品T件的质量和精度，但是，在实际生产中，机床夹具的效率一直是制约机电产品生产快速发展的瓶颈，如何解决机床灾具设计中存在的问题，成为机床夹具设计工作者面临的一大课题。王艺树在基于实例的机床夹具设计系统及其夹具库的研究与开发一文中认为：“迄今为止，夹具仍是机电产品制造中必不可缺的4大工具(刀具、夹具、量具、模具)之一。刀具、量具本身已高度标准化，用户只用按需采购，模具经过多年高速发展，已形成相当规模的产业。而传统的夹具就成为制约产品快速上市的瓶颈企业迫切需要提高夹具设计的效率”。因此，必须认真解决传统的机床夹具存在的问题，促进机电产品的规模化生产。1.4本文主要研究内容本课题主要研究活塞铣开口夹具的工艺分析，；活塞铣开口适用零件工件工件的定位分析（自由度）；活塞铣开口夹具零件夹具定位误差计算、夹紧力的分析与计算；活塞铣开口零件夹具的工作原理；设计中存在的问题；活塞铣开口零件夹具装配工艺设计与仿真。

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活塞环铣开口夹具设计与装配工艺规划

36页 14000字数+说明书+开题报告+中期报告+4张CAD图纸

中期.doc

外文翻译--基于事例推理的夹具设计研究与应用.doc

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活塞环铣开口夹具设计与装配工艺规划开题报告.doc

活塞环铣开口夹具设计与装配工艺规划论文.doc

摘要

　　　本次设计内容涉及了机械制造工艺及机床夹具设计、金属切削机床、公差配合与测量等多方面的知识。

　　　活塞环加工工艺规程及夹具设计是包括零件加工的工艺设计、工序设计以及专用夹具的设计三部分。在工艺设计中要首先对零件进行分析，了解零件的工艺再设计出毛坯的结构，并选择好零件的加工基准，设计出零件的工艺路线；接着对零件各个工步的工序进行尺寸计算，关键是决定出各个工序的工艺装备及切削用量；然后进行专用夹具的设计，选择设计出夹具的各个组成部件，如定位元件、夹紧元件、引导元件、夹具体与机床的连接部件以及其它部件；计算出夹具定位时产生的定位误差，分析夹具结构的合理性与不足之处，并在以后设计中注意改进。

　　　关键词：工序、夹紧、定位。

1 绪论1

1.1 机床夹具介绍1

1 .2夹具的现状及生产对其提出新的要求1

1.3 现代夹具的发展方向2

1.4本文主要研究内容4

2 活塞铣开口夹具形式的选择及原理的确定5

2.1活塞铣开口夹具的性能确定5

2.1.1活塞铣开口夹具结构设计原则5

2.2 活塞铣开口夹具的原理确定5

2.2 研究方案：5

3 活塞铣开口夹具主要零部件的结构设计9

3.1装置零件的结构设计9

3.2定向键与对刀装置设计10

3.3夹紧装置设计12

3.4夹具体零件设计14

4 活塞铣开口夹具的计算分析16

4.1活塞环铣开口零件工艺分析16

4.2活塞环铣开口零件定位分析16

4.3活塞环铣开口夹具切削力和夹紧力的计算16

4.4活塞环铣开口夹具定位误差分析18

5 活塞铣开口夹具的装配工艺设计与仿真19

5.1装配的基本概念19

5.2活塞铣开口夹具的装配20

5.3活塞铣开口夹具的装配工艺规划21

5.3.1活塞铣开口夹具装配流程21

5.3.2装配工艺过程21

5.4装配运动仿真23

5.4.1装配仿真的概念23

5.4.2产品装配仿真的实现24

5.4.3装配后操作24

5.5活塞铣开口夹具的运动演示25

6 总结27

参考文献28

致谢30

毕业设计（论文）知识产权声明31

毕业设计（论文）独创性声明32

所谓机床夹具，是指用来装夹工件，使工件固定在机床上，利于加工成标准件的一种装置。机床夹具作为机械制造业中不可或缺的重要环节，对整个机械制造业的水平提升有着极其蕈要的影响，甚至有些时候是关键性的影响。如果要实现机械制造的现代化，必须首先提高机床夹具的现代化水平，提高机床灾具的制造效率，实现机床灾具的标准化。然而，传统的机床夹具还占据着机械制造业的绝对主导地位，这成为了机械制造业的现代化进程的障碍因素。由于机床灾具的优劣，决定着机电产品标准件的质量和制作精度，机床夹具设计对机电产品的质量有着非常重要的现实意义，随着机械制造领域理论研究的日益深入，机床夹具的设计必将迎来充分发展的时期。

　机床夹具在机电产品制造中是必不可少的工具，机床夹具设计的效果直接决定着机电产品T件的质量和精度，但是，在实际生产中，机床夹具的效率一直是制约机电产品生产快速发展的瓶颈，如何解决机床灾具设计中存在的问题，成为机床夹具设计工作者面临的一大课题。王艺树在《基于实例的机床夹具设计系统及其夹具库的研究与开发》一文中认为：“迄今为止，夹具仍是机电产品制造中必不可缺的4大工具(刀具、夹具、量具、模具)之一。刀具、量具本身已高度标准化，用户只用按需采购，模具经过多年高速发展，已形成相当规模的产业。而传统的夹具就成为制约产品快速上市的瓶颈．企业迫切需要提高夹具设计的效率”。因此，必须认真解决传统的机床夹具存在的问题，促进机电产品的规模化生产。

1.4本文主要研究内容

　　　本课题主要研究活塞铣开口夹具的工艺分析，；活塞铣开口适用零件工件工件的定位分析（自由度）；活塞铣开口夹具零件夹具定位误差计算、夹紧力的分析与计算；活塞铣开口零件夹具的工作原理；设计中存在的问题；活塞铣开口零件夹具装配工艺设计与仿真。

活塞环.jpg

总装配图.gif

内容简介：: 毕业设计（论文）中期报告题目：活塞环铣开口夹具设计与装配工艺规划系（部）：机电工程学院专业：机械设计制造及其自动化班级：学生：学号：指导教师： 2013年03月18日1 论文设计的概况： 1.完成了一篇外文文献的翻译。 2.查阅了相关资料，确定了夹具的设计方案 2.1已经了解夹具的结构及国内外相关研究情况；已经了解了计算机辅助设计方面的基本知识；已经查阅了夹具设计方面的相关资料；掌握了SolidWorks软件的基本建模方法；已经完成了活塞环铣开口夹具总体结构方案的设计；已经基本完成了零件的三维建模；已完成了活塞环铣开口夹具的部分零部件的模型装配。 2.2夹具设计方案我加工的工件是一个活塞环，材料选用HT200，加工的是活塞环上的开口。图1 活塞环（工件）夹具装配草图：图2 夹具装配草图工作原理：将工件置于夹具体3上，用螺母6压紧工件，再用U行压块7压紧工件，U形块开口处，和活塞环开口吻合，再用螺母将双头螺栓上部上紧。对活塞环铣缺口。 2.3夹具设计的优缺点：加工过程操作较为复杂，在加工完一个活塞环缺口后夹具的工作较为复杂，至使工作效率变低，因为此夹具式专用工件夹具，所以工件加工范围较小。夹具的定位套，对刀块的实际较为详细，使得夹具便于定位和夹紧，保证了工件的加工质量。2.4夹具三维建模经过一段时间的工作，完成了夹具基本结构的三维建模。图3 三维建模图图4 夹具三维剖视图二存在问题及解决措施主要问题： 1. 首先是SolidWorks软件不能很好的使用，因此对夹具不能进行仿真模拟，对夹具的质量，以及零件的材料选择等一系列问题不能解决。解决措施：下功夫学习软件，并找寻相关夹具设计书籍进行学习，经常性的向导师和相关教师请教.2. 其次是在夹具的设计过程中，对软件不能正确进行选择，此环节感觉不是很理解。解决措施：查阅相关书籍，经常练习设计软件，向导师请教学习。三后期安排工作：完成夹具及其附属零件的三维模型，优化夹具的整体设计以及完成毕业论文。指导教师签字：年月日毕业设计外文翻译系别机电工程学院专业机械设计制造及其自动化班级姓名学号导师 2013年 3 月 18 日附件1：英文原文Application and developmentOf case based reasoning in fixture design Abstract: Based on the case based designing (CBD) methodology, the fixture similarity is in two respects: the function and the structure information. Then, the computer aided fixture design system is created on case based reasoning (CBR),in which the attributes of the main features of workpiece and structure of fixture as case index code are designed for the retrieve of the similar cases, and the structure and hierarchical relation of case library are set up for store. Meanwhile, the algorithm based on the knowledge guided in the retrieve of the similar cases, the strategy of case adapt at ion and case storage in which the case ident if cat ion number is used to distinguish from similar cases are presented. The application of the system in some projects improves the design efficiency and gets a good result .Keywords: case based reasoning ;fixture design; computer aided design(CAD) Fixtures are devices that serve as the purpose of holding the workpiece securely and accurately, and maintaining a consistent relationship with respect to the tools while machining. Because the fixture structure depends on the feature of the product and the status of the process planning in the enterprise, its design is the bottleneck during manufacturing, which restrains to improve the efficiency and leadtime. And fixture design is a complicated process, based on experience that needs comprehensive qualitative knowledge about a number of design issues including workpiece configuration, manufacturing processes involved, and machining environment. This is also a very time consuming work when using traditional CAD tools (such as Unigraphics, CATIA or Pro/E), which are good at performing detailed design tasks, but provide few benefits for taking advantage of the previous design experience and resources, which are precisely the key factors in improving the efficiency. The methodology of case based reasoning (CBR) adapts the solution of a previously solved case to build a solution for a new problem with 1the following four steps: retrieve, reuse, revise, and retain 1. This is a more useful method than the use of an expert system to simulate human thought because proposing a similar case and applying a few modifications seems to be self explanatory and more intuitive to humans .So various case based design support tools have been developed for numerous areas2-4, such as in injection molding and design, architectural design, die casting die design, process planning, and also in fixture design. Sun used six digitals to compose the index code that included workpiece shape, machine portion, bushing, the 1st locating device, the 2nd locating device and clamping device5. But the system cannot be used for other fixture types except for drill fixtures, and cannot solve the problem of storage of the same index code that needs to be retained, which is very important in CBR6.1 Construction of a Case Index and Case Library1.1 Case index The case index should be composed of all features of the workpiece, which are distinguished from different fixtures. Using all of them would make the operation in convenient. Because the forms of the parts are diverse, and the technology requirements of manufacture in the enterprise also develop continuously, lots of features used as the case index will make the search rate slow, and the main feature unimportant, for the reason that the relative weight which is allotted to every feature must diminish. And on the other hand, it is hard to include all the features in the case index.Therefore, considering the practicality and the demand of rapid design, the case index includes both the major feature of the workpiece and the structure of fixture. The case index code is made up of 16 digits: 13 digits for case features and 3 digits for case identification number.The first 13 digits represent 13 features. Each digit is corresponding to an attribute of the feature, which may be one of“*”, “？”, “1”, “2”,“A”,“B”, “Z”, etc. In which, “*” means anyone, “?” uncertain, “0” nothing.2The system rules: fixture type, workpiece shape, locating model cannot be “*”or“?”. When the system is designed, the attribute information of the three items does not have these options, which means the certain attribute must be selected. The last three digits are the case identification number, which means the 13 digits of the case feature are the same, and the number of these three digits is used for distinguishing them.The system also rules: “000” is a prototype case, which is used for retrieval, and other cases are “001”,“002”, which are used for reference cases to be searched by designers. If occasionally one of them needs to be changed as the prototype case, first it must be required to apply to change the one to “000”, and the former is changed to referential case automatically.The construction of the case index code is shown in Fig.1.1.2 Case libraryThe case library consists of lots of predefined cases. Case representation is one of the most important issues in case based reasoning. So compounding with the index code,.1.3 Hierarchical form of CaseThe structure similarity of the fixture is represented as the whole fixture similarity, components similarity and component similarity. So the whole fixture case library, components case library, component case library of fixture are formed correspondingly. Usually design information of the whole fixture is composed of workpiece information and workpiece procedure information, which represent the fixture satisfying the specifically designing function demand. The whole fixture case is made up of function components, which are described by the function components names and numbers. The components case represents the members. 3(function component and other structure components， main driven parameter, the number, and their constrain relations.) The component case (the lowest layer of the fixture) is the structure of function component and other components. In the modern fixture design there are lots of parametric standard parts and common non standard parts. So the component case library should record the specification parameter and the way in which it keeps them. 2 Strategy of Case RetrievalIn the case based design of fixtures ,the most important thing is the retrieval of the similarity, which can help to obtain the most similar case, and to cut down the time of adaptation. According to the requirement of fixture design, the strategy of case retrieval combines the way of the nearest neighbor and knowledge guided. That is, first search on depth, then on breadth; the knowledge guided strategy means to search on the knowledge rule from root to the object, which is firstly searched by the fixture type, then by the shape of the workpiece, thirdly by the locating method. For example, if the case index code includes the milling fixture of fixture type, the search is just for all milling fixtures, then for box of workpiece shape, the third for 1plane+ 2pine of locating method. If there is no match of it, then the search stops on depth, and returns to the upper layer, and retrieves all the relative cases on breadth.Retrieval algorithms:1)According to the case index information of fixture case library, search the relevant case library;2)Match the case index code with the code of each case of the case library, and calculate the value of the similarity measure;3)Sort the order of similarity measure, the biggest value, which is the most analogical case.Similarity between two cases is based on the similarity between the two cases. features. The calculation of similarity measure depends on the type of the feature. The value of similarity can be calculated for numerical values, for example, compareWorkpiece with the weight of 50kg and 20kg. The value can also be calculated between non numerical values, for example, now the first 13 digits index 4code is all non numerical values. The similarity measure of a fixture is calculated as follows: where S is the similarity measure of current fixture, n is the number of the index feature, is the weight of each feature, is the similarity measure of the attribute of the i2th feature with the attributeof relative feature of the j-th case in the case library. At the same time, , the value counts as follows:.Where is the value of the index attribute of the i-th feature, and is the value of attribute of the relative i-th feature of the j-th case in case library.So there are two methods to select the analogical fixture. One is to set the value. If the values of similarity measure of current cases were less than a given value, those cases would not be selected as analogical cases. When the case library is initially set up, and there are only a few cases, the value can be set smaller. If there are lots of analogical cases, the value should get larger. The other is just to set the number of the analogical cases (such as10), which is the largest value of similarity measure from the sorted order.3 Case adaptation and Case Storage53.1 Case adaptation The modification of the analogical case in the fixture design includes the following three cases:1) The substitution of components and the component;2) Adjusting the dimension of components and the component while the form remains; 3) The redesign of the model.If the components and component of the fixture are common objects, they can be edited, substituted and deleted with tools, which have been designed.3.2 Case storageBefore saving a new fixture case in the case library, the designer must consider whether the saving is valuable. If the case does not increase the knowledge of the system, it is not necessary to store it in the case library. If it is valuable, then the designer must analyze it before saving it to see whether the case is stored as a prototype case or as reference case. A prototype case is a representation that can describe the main features of a case family. A case family consists of those cases whose index codes have the same first 13 digits and different last three digits in the case library. The last three digits of a prototype case are always “000”. A reference case belongs to the same family as the prototype case and is distinguished by the different last three digits.From the concept that has been explained, the following strategies are adopted:1) If a new case matches any existing case family, it has the same first 13 digits as an existing prototype case, so the case is not saved because it is represented well by the prototype case. Or is just saved as a reference case (the last 3 digits are not “000”, and not the same with others) in the case library.2) If a new case matches any existing case family and is thought to be better at representing this case family than the previous prototype case, then the prototype case is substituted by this new case, and the previous prototype case is saved as a reference case.3) If a new case does not match any existing case family, a new case family will 6be generated automatically and the case is stored as the prototype case in the case library.4 Process of CBR in Fixture DesignAccording to the characteristics of fixture design, the basic information of the fixture design such as the name of fixture, part, product and the designer, etc. must be input first. Then the fixture file is set up automatically, in which all components of the fixture are put together. Then the model of the workpiece is input or designed. The detailed information about the workpiece is input, the case index code is set up, and then the CBR begins to search the analogical cases, relying on the similarity measure, and the most analogical case is selected out. If needed, the case is adapted to satisfy the current design, and restored into the case library. The flowchart of the process is shown in Fig.3.5 Illustrating for Fixture Design by CBRThis is a workpiece (seeFig.4). Its material is 45# steel. Its name is seat. Its shape is block, and the product batch size is middle, etc. A fixture is turning fixture that serves to turn the hole, which needs to be designed.7 The value of feature, attribute, case index code and weight of the workpiece is show n in Tab.2.Through searching, and calculating the similarity, the case index code of the most similar case is 19325513321402000, and the detailed information is show n in Tab. 3.8 The similarity is calculated as follows:So the value of similarity measure of the fixture which needs to be designed with the most analogical case in case library is 0.806, and the structure of the most analogical case is shown in Fig.5.After having been substituted the component, modified the locating model and clamp model, and adjusted the relative dimension, the new fixture is designed, and the figure is show n in Fig.6.9As there is not the analogical fixture in the case library, the new fixture is restored in to the case library. The case index code is 19325513311402000.6 ConclusionCBR, as a problem solving methodology, is a more efficient method than an expert system to simulate human thought, and has been developed in many domains where knowledge is difficult to acquire. The advantages of the CBR are as follows: it resembles human thought more closely; the building of a case library which has self learning ability by saving new cases is easier and faster than the building of a rule library; and it supports a better transfer and explanation of new knowledge that is more different than the rule library. A proposed fixture design framework on the CBR has been implemented by using Visual C +, UG/Open API in U n graphics with Oracle as database support, which also has been integrated with the 32D parametric common component library, common components library and typical fixture library. The prototype system, developed here, is used for the aviation project, and aids the fixture designers to improve the design efficiency and reuse previous design resources.附件2：外文翻译基于事例推理的夹具设计研究与应用摘要:根据基于事例的设计方法,提出采用工序件的特征信息和夹具的结构特征信息来描述夹具的相似性,并建立了包括这2方面主要特征信息为基础的事例索引码,设计了事例库的结构形式,创建了层次化的事例组织方式;同时,提出了基于知识引导的夹具事例检索算法,以及事例的修改和采用同族事例码进行相似事例的存贮,形成了基于事例推理的夹具设计.所开发的原型系统在型号工程夹具设计等项目的设计过程中得到了应用,并取得了令人满意的使用效果.关键词: 基于事例的推理夹具设计 CAD夹具是以确定工件安全定位准确为目的的装置，并在加工过程中保持工件与刀具或机床的位置一致不变。因为夹具的结构依赖于产品的特点和在企业规划中加工工序的地位,所以它的设计是制造过程中的瓶颈,制约着效率的提高. 夹具设计是一个复杂的过程,需要有从大量的设计论文中了解质量知识的经验，这些设计论文包括工件的结构设计、涉及加工工艺，和加工环境。当用这些擅长绘制详细设计图的传统的CAD工具（如Unigraphics、CATIA、Pro/E)时,这仍然是一项非常耗时的工作，但是利用以往的设计经验和资源也不能提供一些益处,而这正是提高效率的关键因素. 基于事例推理 (CBR) 的方法适应以往个案解决的办法,建立一个新问题的方法,主要有以下四步骤:检索、利用、修改,并保留.这是一个比用专业系统模仿人类思维有用的使用方法，因为提出一个类似的情况,和采用一些修改,似乎不言自明,而且比人类更直观.所以支持不同事例的设计工具已经在诸多领域中发展起来，如在注射成型及设计、建筑设计、模具设计投死, 规划过程中,还有夹具设计. 孙用六个数字组成代码参数,包括工件的形状、机械部分、轴衬,第一定位装置,第二定位装置和夹紧装置. 但这个系统不能用于除钻床夹具外的其他夹具类型,不能解决储存需要保留的同一参数代码的问题,这在CBR中是非常重要的. 1事例参数和事例图书馆的建立1.1事例参数事例参数应该由工件的所有的特征组成，来区别不同的夹具. 使用他们能够使操作方便. 因为零件的形状是多种多样的, 在生产企业中制造的技术要求也不断发展,许多特征作被用做事例参数将会使搜索速度降低,其主要特征是不重要的,因为分配给每个特征的比重必须减少. 另一方面,事例参数包含所有的特征是困难的。因此,考虑到实际和快速设计的需求,事例参数要包含工件的主要特征和夹具的结构。事例参数代码由16位数组成：13位数是事例特征 3位数是事例识别数字。前13位数代表13个特征。每个数字与特征的一个属性相一致,这可能是*、？、1、2，A、B,，Z，等其中的一个。其中，*是指任何一个,?代表不确定,0代表没有。系统规定:夹具的类型，工件的形状，位置模式不能是*和?。在设计系统时,三个项目的属性信息没有这些选择,这就意味着必须选择确定的属性。最后三位数是事例识别号码,如果事例特征的13位数是一样的,这三个数字10就用来区别他们。该系统还规定:000是用于修正的一个典型事例,其他事例001、002、,这些是用于设计师查找参考事例的. 如果其中一个偶尔需要改变成典型事例,首先它必须要求改成000,前面的自动变成参考事例. 事例索引码的结构如图1所示。 1夹具类型； 6工件重量； 11夹紧模型； 2工件形状； 7工件刚度； 12夹具体； 3工件材料； 8加工内容； 13其他； 4批量； 9过程所有物； 14到16事例识别码； 5工件比例； 10定位模型；图1 事例索引码的结构1.2事例库事例库由许多预定义的事例组成。事例的描述是基于事例推理的最重要的问题之一。所以由索引码复合。1.3 事例的层次化夹具的结构相似被认为是整个夹具，成分和内容相似。所以，整个夹具事例库，成分事例库，夹具的成分事例库形成相同。整个夹具的设计资料通常是由工件资料和工件加工资料组成,这就意味着夹具的设计应满足特别功能的需求.全部夹具事例是由功能成分组成，它是用功能成分的名字和数字来进行描述的。成分事例代表成员（成分功能和其他结构成分，主要驱动参数，数字，和它们的约束关系）。成分事例（夹具的最低层）是功能成分和和其他成分的结构。在现代夹具设计中有很多参数化准件和普通非标准件。所以成分事例图书馆应记录特殊参数和保持它们的方法。2事例修改的策略在基于事例的夹具设计中，最重要的是相似点的修改，这样能有助于获得最相似的事例，以及缩短适应时间。根据夹具设计的需求，事例修改的策略使最接近的事例方法和知识指导结合起来。首先在深度上查找，然后在宽度上；知识指导策略意味着在来自客观事物根源的知识规则上查找，这就要首先查找固定类型，然后查找工件的形状，第三查找定位方法。例如，如果事例索引码包括夹具类型的磨削夹具，就只查找所有的磨削夹具，然后查找工件形状的盒子，第三查找一个平面两个销的定位方法。如果没有合适的，就查找深度标点，然后回到最上层，然后再找所有与宽度相关的事例。修改方法：1）根据夹具事例库的事例索引信息，查找有关事例库。2）将事例索引码与事例库的每个事例码匹配，然后计算相似尺寸的价值。3）整理相似尺寸的次序，最大的架子是最类似的事例。两个事例之间的相似点是基于两个事例特征之间的相似点。相似点尺寸的计算依靠特征的类型。相似点的价值可以通过数字化的价值来计算，例如比较重量分别是50kg 和 20kg的工件。非数字化的价值也能计算，例如，现在前13位索引码都是非数字化的价值。一个夹具的相似尺寸的计算公式如下：12其中S表示通用夹具的相似尺寸，n表示索引特性数，表示每个特性的重量，表示事例库中特性和相关夹具的特性的相似尺寸。同时，，数值计算如下：其中表示第i个特征的索引特性值，表示事例库中第j个事例的第i个特征的特性值。所以有两种方

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