鑄鐵拔叉零件夾具設計【含非標件】【全套含CAD圖紙、說明書】

資源目錄里展示的全都有，所見即所得。下載后全都有,請放心下載。原稿可自行編輯修改=【QQ：401339828 或11970985 有疑問可加】 編號： 畢業(yè)設計(論文)開題報告 題 目： 拔叉零件夾具 學　　院： 機電工程學院 專 業(yè)： 機械設計制造及其自動化 學生姓名： 學 號： 指導教師單位： 姓 名： 職 稱： 題目類型：¨理論研究 ¨實驗研究 t工程設計 ¨工程技術研究 ¨軟件開發(fā) 年3月1日 1．畢業(yè)設計的主要內容、重點和難點等 （1）設計內容 拔叉是一種輔助零件，好的夾具設計可以提高產品勞 動生產率，保證和提高加工精度，降低生產成本等，還可以擴大機床的使用范圍，從而使產品生產在保證精度的前提下提高效率、降低成本。當今激烈的市場競爭 和企業(yè)信息化的要求，企業(yè)對夾具的設計及制造提出了更高的要求。本次設計是對鑄鐵拔叉進行加工工藝及夾具設計，具體內容如下： 1、查閱相關資料，了解鑄鐵拔叉加工工藝及夾具工作原理； 2、進行方案選擇論證，優(yōu)選出最佳方案； 3、分析鑄鐵拔叉加工工藝，確定定位方案，設定定位元件，選擇加緊方案及加緊機構設計，分析零件確定完成加工所需夾具的定位方案，設計鑄鐵拔叉加工工藝及夾具設計一套； 4、繪制裝配圖、零件圖，編制設計計算說明書； 5、了解相關的國家標準的應用。 （2） 設計重點和難點 1） 重點： 工序的劃分和定位基準的選擇，在開始的時候，要認真分析零件圖，了解撥 叉的結構特點和技術要求。加工表面的平行度、粗糙度、垂直度，注意零件各孔 系自身精度（同軸度，圓度，粗糙度等）和它們的相互位置精度。 2） 難點： 夾具設計要確定工件定位是否正確，定位精度是否滿足要求，工件夾緊是否 可靠等等。 2．準備情況（查閱過的文獻資料及調研情況、現(xiàn)有設備、實驗條件等） （1）國內外研究現(xiàn)狀及發(fā)展趨勢（含文獻綜述） 夾具的發(fā)展200 已經(jīng)有多年的歷史，大致經(jīng)歷了三個階段：第一階段，夾 具在工件加工、制造的各工序中作為基本的夾持裝置，發(fā)揮著夾固工件的最基本 功用。第二階段，隨著軍工生產及內燃機，汽車工業(yè)的不斷發(fā)展，夾具逐漸在規(guī) 模生產中發(fā)揮出其高效率及穩(wěn)定加工質量的優(yōu)越性，各類定位、夾緊裝置的結構 也日趨完善，夾具逐步發(fā)展成為機床—工件—工藝裝備工藝系統(tǒng)中相當重要的組 成部分。這一階段夾具發(fā)展的主要特點是高效率。第三階段，在現(xiàn)代化生產的今 天，各類高效率，自動化夾具在高效，高精度及適應性方面，已有了相當大的提 高。隨著電子技術，數(shù)控技術的發(fā)展，現(xiàn)代夾具的自動化和高適應性，已經(jīng)使夾 具與機床逐漸融為一體，使得中，小批量生產的生產效率逐步趨近于專業(yè)化的大 批量生產的水平。這一階段，夾具的主要特點是高精度，高適應性?？梢灶A見， 夾具在不一個階段的主要發(fā)展趨勢將是逐步提高智能化水平。 （2）主要參考文獻 通過查閱以下的相關的權威文獻，研究有關拔叉零件夾具方面的知識，了解拔叉的基本結構，做到設計講依據(jù)的科學嚴謹?shù)膽B(tài)度。 [1] 孫已德. 機床夾具圖冊.[M].北京：機械工業(yè)出版社，1994 [2] 李慶余、張佳主編.機械裝備設計.[M]. 機械工業(yè)出版社，2003 [3] 吳宗澤. 機械設計實用手冊.[M]. 北京：機械工業(yè)出版社，2002 [4] 孫麗媛. 機械制造工藝及專用夾具設計指導.[M].北京：冶金工業(yè)出版社，2002 [5] (日)藤森洋三著；賀相譯. 機構設計實用構思圖冊．北京：機械工業(yè)出版社，1990 [6] 濮良貴.機械設計.[M].北京：高教出版社.2001.6 [7] 廖念釗等. 互換性與技術測量.[M].北京：中國計量出版社，2000 [8] 張鄂.現(xiàn)代設計方法[M].西安：西安交通大學出版社，1999 [9] Homer D·Eckhardt.Kinematic Design of Machines and Mechanisms. McGraw-Hill.1998 [10] J.Lal．Theory of mechanisms & machines[M]．Metroplitan Book Co., 1993 （3）現(xiàn)有設備 微型計算機一臺；CAD設計分析軟件（CATIA） 3、實施方案、進度實施計劃及預期提交的畢業(yè)設計資料 （1）實施方案 1、查閱以上參考文獻積累知識，和老師溝通并分析整體流程，進行多種方案論證比較，確定最后的設計方案。 2、給出的鑄鐵拔叉加工圖要求進行。 3、繪制主要零部件圖和總體裝配圖。 4、設計說明書的編寫。 （2）進度實施計劃 1）調研，收集資料，查閱相關文獻，了解撥叉的基本結構 （第1周） 2）掌握加工工藝設計的基本思路，初步擬定撥叉零件的工藝過程 （第2周） 3）總結前期工作，分析撥叉的作用并繪制零件圖 （第3-4周） 4）確定加工工藝；編制零件的機械制造工藝規(guī)程 （第5-6周） 5）設計關鍵工序的夾具，繪制夾具裝配圖和只要零件工作圖 （第7-10周） 6）與老師討論，對零件的主要技術進行分析，規(guī)程進行修改和完善（第11周） 7）總結前面的工作，開始撰寫論文 （第12周） 8）完成論文初稿，與老師交流，修訂初稿 （第12-15周） 9）總結相關知識，準備答辯 (第16周)（3）預期提交畢設設計資料 指定整個畢業(yè)設計學生應該完成的所有工作包括： 1、完成二萬字左右的畢業(yè)設計說明書（論文）；在畢業(yè)設計說明書（論文）中必須包括詳細的300-500個單詞的英文摘要； 2、獨立完成與課題相關，不少于四萬字符的指定英文資料翻譯（附英文原文）； 3、繪制鑄鐵拔叉夾具總裝配圖和主要零部件圖，繪圖工作量折合A0圖紙3張以上，其中必須包含兩張A3以上的計算機繪圖圖紙。 指導教師意見 指導教師（簽字）： 2016年3月1日 開題小組意見 開題小組組長（簽字）： 2016年3月1日 院（系、部）意見 主管院長（系、部主任）簽字： 2016年3月1日 - 4 - 編號： 畢業(yè)設計(論文)外文翻譯 （原文） 院（系）： 機電工程學院 專 業(yè)： 機械設計制造及其自動化 學生姓名： 學 號： 指導教師單位 姓 名 職 稱： 年 6月 3日 Content-based search of mechanical assemblies Abstract Title of Thesis: Degree Candidate: Degree and Year: Thesis directed by: The increased use of 3D CAD systems by product development organizations has resulted in large databases of assemblies; this explosion of assembly data will continue in the future. Currently, there are no effective content-based techniques to search these databases. Ability to perform content- based searches on these databases is expected to help the designers in the following two ways. First, it can facilitate reuse of existing assembly designs, thereby reducing the design time. Second, a lot of useful Design for Manufacturing and Assembly (DFMA) knowledge is embedded in existing assemblies. Therefore a capability to locate existing assemblies and examine them can be used as a learning tool by the designers to learn from the existing assembly designs and hence transfer the best DFMA practices to new designers. This thesis describes a system for performing content-based searches on assembly databases. It lists the templates identified for comprehensive search definitions and describes algorithms to perform content-based searches for mechanical assemblies. The characteristics of mechanical assemblies were identified and categorized based on their similarity and computational complexity to perform comparison. The characteristics were extracted from the CAD data to prepare a CAD independent signature of the assembly. The search methodology consists of exact and approximate string matching, number matching and computing graph compatibility. Various research groups have solved the former two problems. This thesis describes a new algorithm to solve graph compatibility problem using branch and bound search. The performance of this algorithm has been experimentally characterized using randomly generated graphs. This search software provides a CAD format independent tool to perform content based search of assemblies based on the form of assemblies. The capabilities of the search software have been illustrated in this thesis through several examples. This search tool can contribute to significantly reduce the design time and reuse of the knowledge in existing designs. Chapter 1 INTRODUCTION This chapter is arranged in the following manner: Section 1.1 discusses the mechanical assemblies in CAD software systems, Section 1.2 describes the motivation behind the research for assembly search system, Section 1.3 describes the issues involved in the research and Section 1.4 describes the outline of the thesis. Most of the research in this thesis is based on the work reported in [Desh05, Gupt06]. 1.1 Mechanical Assemblies in CAD Over the last ten years, 3D CAD systems have become very popular in the industry. These CAD systems are being used to generate 3D models of parts and assemblies. These models are used as a basis for engineering analysis and generating manufacturing plans. 3D models also allow virtual prototyping and hence reduce the need for physical prototyping. Nowadays, organizations routinely set up databases of CAD models to enable all participants in the product development process to have access to 3D data to support their functions. Specially, design, manufacturing and service engineers are expected to greatly benefit from these databases. Design engineers can access the designs of parts and assemblies in the database to design a product for a similar application. Manufacturing engineers can use these databases to find the manufacturing plans and vendors to manufacture parts and assemblies. Service engineers can use the strategy to disassemble and assemble the products for maintenance and servicing. These databases are updated with the latest versions of parts and assemblies and hence significantly improve information dissemination. CAD databases for even moderate size companies are expected to be large in size. A product assembly can contain many subassemblies and each subassembly can contain 9 many parts. Therefore, even a small organization that has multiple product lines may add hundreds of assemblies to their database every year. The mechanical assemblies consist of either the pointers to or a copy of the geometry of the constituent parts. An assembly in a CAD system can be made of individual parts or subassemblies. The subassemblies are made of its constituent parts. The constituent parts and sub assemblies are represented in a tree structure that represents the bill of materials of the assembly. The constituent parts and subassemblies are placed in specific position using part mating conditions. The assemblies are virtual representation of a product or an important part of a product. Some products have articulations. The articulation is shown in assembly by joints. These joints can be simulated to show the movement of different parts of the assembly. Before a product is manufactured, different analysis are carried out on the parts and assembly. Some examples of such type of analysis are manufacturability, strength and motion analysis. Often the results of such analysis including the product manufacturing (PMI) data are stored with the assemblies. The mechanical assemblies thus contain much more information about the products of an organization as compared to CAD files that only contain the geometry of a part in the product. The assembly databases, besides supporting downstream manufacturing and service operations, can be very useful during the design phase as well. There are two main uses of assembly database during the design stage. ? The first possible usage is to locate existing assemblies that can be reused in a new product. Such reuse of existing designs is beneficial from many different perspectives. It reduces design time by eliminating the need for modeling and analysis for the assembly being reused. Furthermore, the existing assembly is already tested and has an established manufacturing plan. This further reduces the product development time and cost. Sharing assemblies across multiple product lines also allows a company to take advantage of the economy of scale. The design of universal joint shown in the figure 1.1 can be reused to design another universal joint. Figure 1.1: A universal joint – reuse of existing design ? The second possible usage is to provide access to existing design knowledge. Designing assemblies requires considerable effort. Creating good assembly designs require thoughtful analysis and careful application of Design for Manufacturing and Assembly (DFMA) principles. The design thumb rules used in an organization are embedded in the design. These rules include the tweaking of design to suit the manufacturing capabilities in the organization and its vendors. New designers can adopt and copy successful design templates. Moreover, once designers manage to find an assembly with the desired characteristics, they can also access associated data such as cost, reliability, and failure reports. The camera frame assembly shown in the figure 1.2 can be used to access the knowledge about an assembly that fit together tightly. Figure 1.2: A camera frame – use of design knowledge 1.2 Motivation This section describes the motivation behind this work. 1.2.1 Need for assembly search system Saaksvuori reports that up to 70 percent of a designers time can be saved if the existing knowledge base of an organization can be reused for new designs. [Saak04] It is thus very important to have the capability to search the database based on any characteristics for a desired assembly. Currently, content-based search tools do not exist for searching assemblies based on the specified criteria. Therefore, designers locate assemblies by combining the text based and part search methods and manually opening various files and browsing through them using a CAD system. This is a highly inefficient use of designer’s time, and becomes a serious problem as the numbers of assemblies in the database grow. This also requires that designers should have access to the CAD software. 3D CAD software are costly and it would be helpful to search database without requiring to access CAD software. If a designer can access the information of an assembly and study the design without using CAD, it would result in significant cost reduction. 1.2.2 Existing search methods and their limitations Designers have access to several types of search tools. If the assemblies are stored in hard drives, they can use file name-based search tools. This strategy only works if a meaningful file naming convention based on assembly contents is adopted. However, developing and deploying a content- based naming convention is impractical in many large organizations. Many organizations have manufacturing plants located across different geographical locations. The merger of two different organizations in different geographical locations can also lead to two completely different naming conventions that are individually sufficient to cater to the needs of the different manufacturing units but cannot be used as search criteria in a single assembly search system. In such case, information about product designs cannot be used by designers in two different manufacturing units. A newly developed convention cannot be used to search the legacy data in the organization. Any organization usually has very large quantity of legacy data that makes it very difficult to change or implement naming conventions followed in the organization. Another way is to attach text notations to assemblies and store them in a Product Data Management (PDM) database. This scheme only provides limited search capabilities and has a limited discrimination power. Moreover, assemblies need to be manually annotated.The text based search cannot be used to define all attributes of the mechanical assembly. Moreover, manual annotations introduce human errors that cannot be avoided thereby reducing the accuracy of a tool that searches for assemblies based on these text attributes. In the recent past, several geometry-based search tools have emerged. However, these tools, although useful for part searches, are not very effective for assemblies. They can only account for the overall shape of the assembly and cannot account for relationships and structure that exist in assemblies. The overall shape may differ for an articulated assembly. For example, the four bar link mechanism shown in the figure 1.3 occupies different volume in different positions. Only text based search tools and geometry based search tools are clearly insufficient to search for assemblies. This research has been started to provide a content based assembly search tool for designers an organization. Figure 1.3: Slider crank mechanism occupying different volumes due to different position of relative parts 1.3 Research Issues 1.3.1 Desired characteristics of software search system The goal of this research is to develop a content-based assembly search system for searching assemblies from a database of existing assemblies based on different characteristics. The characteristics used by the system to search the database need to be extensive and also include most of the characteristics of a typical assembly. Hence, the system will need to support a comprehensive list of characteristics of assemblies based on which the user can define a search. The characteristics included in the system are enumerated in subsequent chapters. The system should be flexible and allow the user to search based on any combination of the characteristics. It should also handle cases that result in too few or too many search results. Thus, if the search system results are too few then the user should be able to lower the constraints (strictness) of the search criteria by increasing the cut-off values. Also, if the search results are too many then the user should be able to perform iterative refinement. This is achieved by constraining the search by including more assembly characteristics in Search Criteria the search, then performing search and again refining search definition. This iterative refinement is very effective in producing the right number of search results. At any time in the search, the user should be able to exclude any assembly from further search. Finally, the system should have an easy- to-use interface and should be efficient so as to locate assemblies from a database in few seconds. The objectives of this research are summarized in the figure 1.4. Search Algorithms Search Strategies Content based assembly search software Figure 1.4: Objectives of research The thesis describes a system for performing content-based searches on an assembly database. It is followed by the description of the templates for comprehensive search definitions that have been identified after studying various assembly models used in modern CAD systems. It also describes the algorithms developed to perform content- based searches for mechanical assemblies based on these search definition templates. These algorithms have been implemented in a system. The thesis also has illustrations of the possible usages of the prototype system with some examples. 1.3.2 Identifying and extracting characteristics of assemblies for search The initial part of research is to identify a comprehensive set of characteristics of the assembly. These characteristics should cover all possible information about an assembly that can be used by a designer to search for the assembly. To build a list of all the characteristics of an assembly on which search can be performed, an extensive review of existing CAD systems and literature in the assembly modeling field [Anan96, Boot94, Brun00, DeFa87, Home91, Khos89, Lee85, Lee93, Moll93, Shah93] was performed. We decided to base our system with the Pro/Engineer CAD system. Therefore, we also studied the list of all characteristics available in Pro/Engineer. Based on the published assembly characteristics and information available in Pro/Engineer models, we developed a preliminary list of assembly characteristics to support content-based searches. To ensure that these characteristics are not specific to Pro/Engineer, we also studied the assembly characteristics available in another CAD system – Unigraphics. We ensured that our list is compatible with the information available in Unigraphics. This research shows that data used in the search can be extracted from a CAD system. The application programming interface (API) of a CAD system can be used to extract the data in the signature of the assembly before execution. As characteristics used in this research are based on Pro/Engineer, API program for that CAD should be used to demonstrate the capability to extract the signature from the CAD system. This will enable the search system to work independent of any CAD system. The figure 1.5 summarizes the process of identifying assembly characteristics. Assembly Models in Published Literature Verify availability of data Pro/Engineer Unigraphics Add additional assembly characteristics Set of Search Criteria Figure 1.5: Method to identify assembly characteristics An assembly has large quantity of characteristics associated with it. It is important to have an intuitive distinction between different characteristics to develop a search system that is based on all of these characteristics and yet has an intuitive interface to define search. The identified characteristics were categorized into four main categories. The assembly design process was used as the basis of categorization of characteristics. The figure 1.6 shows the top level characteristics of an assembly. Relationships Assembly Parts Joints Mating Figure 1.6: Top level assembly characteristics Then, a suitable format, independent of any CAD system, was developed to store all the characteristics in an assembly as its signature. The assembly format defined in [Gupt01] is used as basis to store the signature of an assembly. In [Gupt01], each part is described by a name, a pointer to the geometry, and a transformation, which places the part in its assembled position in the assembly. Every joint is described by a type, a name, and the names of the base and attached parts forming the joint. The joint and mating condition data stored in the signature can be read to construct a graph. The representation is used to support only the mating conditions and joints that are supported in Pro/Engineer. The signature fully represents an assembly and does not require the use of CAD files. Thus, these assemblies can be viewed and searched independent of any CAD software. As these signatures are not dependent on any single CAD software, they can be used to browse and search 10 assemblies designed using different CAD software. This capability is important for large organizations that use different CAD softwares or for those who collaborate with external organizations in design. 1.3.3 Search methodology for different characteristics Many of the characteristics of assembly are text or geometry based. For search based on text, string matching algorithms can be used. This problem has been studied extensively and various algorithms for exact and approximate matching strings are available. For search based on geometry, various approaches have been suggested for exact geometry match and either of them can be used to compare geometry. This research will undertake experiments to optimize the search time by ranking the efficiency of the each of the criteria. The search based on part mating condition will be based on graph compatibility. The user would define a graph which can be a part of a graph representing mating conditions in an assembly from the database. The two graphs need to be matched with each other and this would require a graph compatibility algorithm. Search based on joint relations uses double, as each relation between two different joints in the query as well as database is stored in a double. It is required to create data structure that can store and provide efficient access to all joint relations defined in either query or database. The search method involves exact string comparison to find the existence of joint relations in query and assemblies from database. 1.4 Outline of Thesis The thesis has been arranged in the following way. The four major categories of assembly characteristics that are used for defining search are dealt with in different chapters as described below. The assembly statistics include assembly characteristics such as size and number of parts in the assembly. Chapter 3 deals with the search based on these statistics. Some parts in an assembly can have specific characteristics with regard to material, size and other characteristics. Use of 19 an uncommon part in an assembly characterizes the assembly and can be used as search criteria. Chapter 4 deals with the searches that utilize characteristics of the constituent parts. The mating conditions in an assembly play an important role in its function. Therefore, we need to support searches based on the type of mating conditions that exist in assemblies. This search is discussed in Chapter 5. Joints in articulated assemblies define the possible mot