载重汽车悬架减震器设计【含7张cad图纸+文档全套资料】
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世界最新机械设计理念
来源:中国科技期刊
摘要:根据目前国内外设计学者进行机械产品设计时的主要思维特点,将产品方案的设计方法概括为系统化、结构模块化、基于产品特征知识和智能。这几种方法的特点及其相互间的有机联系,提出产品方案设计计算机实现的努力方向。
关键词:机械产品方案设计方法发展趋势
设计文件是将语义设计网作为设计工具,在其开发的活性语义设计网ASK中,采用结点和线条组成的网络描述设计,结点表示元件化的单元(如设计任务、功能、构件或加工设备等),线条用以调整和定义结点间不同的语义关系,由此为设计过程中的所有活动和结果预先建立模型,使早期设计要求的定义到每一个结构的具体描述均可由关系间的定义表达,实现了计算机辅助设计过程由抽象到具体的飞跃。
系统化设计方法
系统化设计方法的主要特点是:将设计看成由若干个设计要素组成的一个系统,每个设计要素具有独立性,各个要素间存在着有机的联系,并具有层次性,所有的设计要素结合后,即可实现设计系统所需完成的任务。
系统化设计思想于70年代由德国学者Pahl和Beitz教授提出,他们以系统理论为基础,制订了设计的一般模式,倡导设计工作应具备条理性。德国工程师协会在这一设计思想的基础上,制订出标准VDI2221技术系统和产品的开发设计方法。
1. 将用户需求作为产品功能特征构思、结构设计和零件设计、工艺规划、作业控制等的基础,从产品开发的宏观过程出发,利用质量功能布置方法,系统地将用户需求信息合理而有效地转换为产品开发各阶段的技术目标和作业控制规程的方法。
2. 将产品看作有机体层次上的生命系统,并借助于生命系统理论,把产品的设计过程划分成功能需求层次、实现功能要求的概念层次和产品的具体设计层次。同时采用了生命系统图符抽象地表达产品的功能要求,形成产品功能系统结构。
3. 将机械设计中系统科学的应用归纳为两个基本问题:一是把要设计的产品作为一个系统处理,最佳地确定其组成部分(单元)及其相互关系;二是将产品设计过程看成一个系统,根据设计目标,正确、合理地确定设计中各个方面的工作和各个不同的设计阶段。
由于每个设计者研究问题的角度以及考虑问题的侧重点不同,进行方案设计时采用的具体研究方法亦存在差异。下面介绍一些具有代表性的系统化设计方法。
4. 设计元素法
用五个设计元素(功能、效应、效应载体、形状元素和表面参数)描述“产品解”,认为一个产品的五个设计元素值确定之后,产品的所有特征和特征值即已确定。我国亦有设计学者采用了类似方法描述产品的原理解。
5. 图形建模法
研制的“设计分析和引导系统”KALEIT,用层次清楚的图形描述出产品的功能结构及其相关的抽象信息,实现了系统结构、功能关系的图形化建模,以及功能层之间的联接。
将设计划分成辅助方法和信息交换两个方面,利用Nijssen信息分析方法可以采用图形符号、具有内容丰富的语义模型结构、可以描述集成条件、可以划分约束类型、可以实现关系间的任意结合等特点,将设计方法解与信息技术进行集成,实现了设计过程中不同抽象层间信息关系的图形化建模。
6. “构思”—“设计”法
将产品的方案设计分成“构思”和“设计”两个阶段。“构思”阶段的任务是寻求、选择和组合满足设计任务要求的原理解。“设计”阶段的工作则是具体实现构思阶段的原理解。
将方案的“构思”具体描述为:根据合适的功能结构,寻求满足设计任务要求的原理解。即功能结构中的分功能由“结构元素”实现,并将“结构元素”间的物理联接定义为“功能载体”,“功能载体”和“结构元素”间的相互作用又形成了功能示意图(机械运动简图)。方案的“设计”是根据功能示意图,先定性地描述所有的“功能载体”和“结构元素”,再定量地描述所有“结构元素”和联接件(“功能载体”)的形状及位置,得到结构示意图。Roper,H.利用图论理论,借助于由他定义的“总设计单元(GE)”、“结构元素(KE)”、“功能结构元素(FKE)”、“联接结构元素(VKE)”、“结构零件(KT)”、“结构元素零件(KET)”等概念,以及描述结构元素尺寸、位置和传动参数间相互关系的若干种简图,把设计专家凭直觉设计的方法做了形式化的描述,形成了有效地应用现有知识的方法,并将其应用于“构思”和“设计”阶段。
7. 键合图法
将组成系统元件的功能分成产生能量、消耗能量、转变能量形式、传递能量等各种类型,并借用键合图表达元件的功能解,希望将基于功能的模型与键合图结合,实现功能结构的自动生成和功能结构与键合图之间的自动转换,寻求由键合图产生多个设计方案的方法。
提倡在产品功能分析的基础上,将产品分解成具有某种功能的一个或几个模块化的基本结构,通过选择和组合这些模块化基本结构组建成不同的产品。这些基本结构可以是零件、部件,甚至是一个系统。
本结构应该具有标准化的接口(联接和配合部),并且是系列化、通用化、集成化、层次化、灵便化、经济化,具有互换性、相容性和相关性。我国结合软件构件技术和CAD技术,将变形设计与组合设计相结合,根据分级模块化原理,将加工中心机床由大到小分为产品级、部件级、组件级和元件级,并利用专家知识和CAD技术将它们组合成不同品种、不同规格的功能模块,再由这些功能模块组合成不同的加工中心总体方案。
以设计为目录作为选择变异机械结构的工具,提出将设计的解元素进行完整的、结构化的编排,形成解集设计目录。并在解集设计目录中列出评论每一个解的附加信息,非常有利于设计工程师选择解元素。
网络技术的蓬勃发展,异地协同设计与制造,以及从用户对产品的功能需求→设计→加工→装配→成品这一并行工程的实现成为可能。但是,达到这些目标的重要前提条件之一,就是实现产品方案设计效果的三维可视化。为此,不仅三维图形软件、智能化设计软件愈来愈多地应用于产品的方案设计中,虚拟现实技术以及多媒体、超媒体工具也在产品的方案设计中初露锋芒。目前,德国等发达国家正着力于研究超媒体技术、产品数据交换标准STEP,以及标准虚拟现实造型语言上基于虚拟环境的标准交换格式)在产品设计中的应用。
机械产品的方案设计正朝着计算机辅助实现、智能化设计和满足异地协同设计制造需求的方向迈进,由于产品方案设计计算机实现方法的研究起步较晚,目前还没有成熟的、能够达到上述目标的方案设计工具软件。作者认为,综合运用文中四种类型设计方法是达到这一目标有效途径。虽然这些方法的综合运用涉及的领域较多,不仅与机械设计的领域知识有关,而且还涉及到系统工程理论、人工智能理论、计算机软硬件工程、网络技术等各方面的领域知识,但仍然是产品方案设计必须努力的方向。国外在这方面的研究已初见成效,我国设计学者也已意识到CAD技术与国际交流合作的重要性,及其应当采取的措施。
基于产品特征知识设计方法的主要特点是:用计算机能够识别的语言描述产品的特征及其设计领域专家的知识和经验,建立相应的知识库及推理机,再利用已存储的领域知识和建立的推理机制实现计算机辅助产品的方案设计。
机械系统的方案设计主要是依据产品所具有的特征,以及设计领域专家的知识和经验进行推量和决策,完成机构的型、数综合。欲实现这一阶段的计算机辅助设计,必须研究知识的自动获取、表达、集成、协调、管理和使用。为此,国内外设计学者针对机械系统方案设计知识的自动化处理做了大量的研究工作,采用的方法可归纳为下述几种。
江苏科技大学苏州理工学院毕业设计(论文)开题报告概述表
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毕业设计(论文)题目
载重汽车悬架减震器设计及其三维建模
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随着社会的不断发展,人们对汽车的要求也越来越高。包括有汽车的动力性、经济性、制动性、操纵稳定性、平顺性、通过性等性能的要求。减震器是安装在车体与负重轮之间的一个阻尼元件,其作用是衰减车体的振动并阻止共振情况下车体振幅的无限增大,能减小车体振动的振幅和振动次数,因而能延长弹性元件的疲劳寿命和提高人乘车的舒适性[1]。长期以来,人们对汽车的平顺性一直都在研究,在技术上也有重大的改驶员操纵轻便,乘员更加舒服。
因外部条件的不同,对减振器的使用要求也会相应的不同。在不同的国家或不同的地区,他们各自的天气环境、道路建筑等都有着很大的区别。单一的减振器是可能都满足他们的性能要求。随着社会的发展,汽车市场出现了细分化。纯黑色的“福特”时代,早已经过去,针对各国道路交通情况,各国汽车生产商们开始生产有属于自己特色的汽车了。本文就是针对我国大多数城市道路情况,而进行研究设计的。
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为加速车身振动的衰减,改善汽车行使平顺性,大多数轿车的悬架内都装有减震器。减震器和弹性元件是并联安装的。其中采用最广泛的是液力减震器,又称筒式液力减振器,现简称为筒式减振器。根据结构形式不同,减振器分为摇臂式和筒式两种。而筒式减震器工作压力仅在2.5~5MPa,但是它的工作性能稳定而在现代的汽车上得道广泛的应用。又可以分为单筒式、双筒式和充气筒式三种[3]。减震器的阻尼力越大,振动消除得越快,但却使并联的弹性元件的作用不能充分发挥;还可能导致连接件及车架损坏。通常为了保证伸张过程内产生的阻尼力比压缩行程内产生的阻尼力大得多,所以伸张阀弹簧刚度和预紧力比压缩阀大;在同样油压力作用下,伸张阀及相应的通常缝隙的同道截面积总和小于压缩阀及相应的通常缝隙的通常截面积总和。这样也保证了悬架在压缩行程内,减震器的阻尼力较小,以便充分利用弹性元件的弹性来缓和冲击;在伸张行程内,减震器的阻尼力应较大,以求迅速减振[2]。由于汽车行驶的路面状况不同,所用的减震器要求也会有所不同。
参考文献:
[1]中国知识网 “充气式汽车减震器的研制” 哈尔滨工业大学 高起波 曾祥荣
[2]《汽车构造 第2版》 吉林大学 陈家瑞 主编 机械工业出版社
[3]《汽车设计 第4版》 吉林大学 王望予 主编 机械工业出版社
[4]《机械设计与研究》的“新型减震器的研究”华中理工大学 李辉 何程
[5]《橡胶减震器设计与计算》 第二研究室 王光
[6]《可调阻尼减振器优化设计的研究》 吉林大学硕士学问论文 孙雪梅
[7]《汽车工程手册 设计篇》《汽车手册》编辑委员会编 人民交通出版社
[8]《液压系统设计简明手册》 杨培元 朱福元主编 机械工业出版社
[9]《减振器设计专家系统的研究与开发》 重庆大学 李若刚
[10]《机械设计手册》 机械设计手册编委会 机械工业出版社
[11]《液压气动技术速查手册》 张利平 等编著 化学工业出版社
[12]《国内外通用标准件手册》 凤凰出版传媒集团 江苏科学技术出版社
[13]《汽车高级减振器油的开发和应用》 蒋振森 王家乃
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本文的设计是要满足一般性能要求,具体是:一是要具有一般的舒适性;二是可以满足中国现代一般城市道路的使用要求;三能保证有足够的使用寿命;四是在使用期间保证汽车行驶平顺性的性能稳定。在减振器中,流通阀和补偿阀是一般的单向阀,其弹簧很弱。当阀上的油压作用力同向时,只要很小的油压,阀便能开启;压缩阀和伸张阀是卸载阀,其弹簧较强,预紧力较大,只有当油压到一定程度时,阀才能开启;而当油压降低到一定程度时,阀即自行关闭。根据它们不同的工作要求,各阀系设计计算和装配都有所不同。
根据以上要求,本文设计的基本步骤有:
1)确定减振器的阻尼系数和相对阻尼系数;
2)计算出各机械结构的主要参数,其中包括缸筒、储油缸筒、活塞杆导向座和活塞的尺寸设计计算;
3)在总体参数出来以后,就对减振器连接结构、密封结构的设计,弹簧片以及减振器油的选择等;
4)总体参数确定后,建立各阀系的力学模型、各阀系模型以及阻尼阀阀片的挠曲变形模型,完成各阀系的设计计算。
5)完成设计计算后,对主要受力部件进行校核验证。
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(1)通过查阅相关资料,掌握汽车减震器的主要参数。
(2)充分考虑已有汽车减震器的优缺点来确定电动滚筒的总体设计方案,对现有装置的不足进行分析。
(3)对设计的汽车减震器进行修改和优化,最终设计出能满足要求的汽车减震器。
研究技术路线
(1)根据题目和原始数据查看相关资料,了解当今国内外汽车减震器的发展现状及发展前景,撰写文献综述和开题报告。
(2)根据产品功能和技术要求提出多种设计方案,对各种方案进行综合评价,从中选择较好的方案,再对所选择的方案做进一步的修改或优化,最终确定总体设计方案。
(3)具体设计汽车减震器的驱动装置、工作装置等。
(4)对所设计的机械结构中的重要零件进行校核计算,如齿轮、轴、轴承等,保证设计的合理性和可行性。;
(5)绘制零件图、装配图,完成要求的图纸量;
(6)整理各项设计资料,撰写论文。
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The worlds Latest Mechanical Design Conceptssource:China Science and Technology JournalAbstract:According to scholars at home and abroad to carry out mechanicaldesign product design features of the main ideas, product design method of theprogramsummarizedassystematic,modularstructure,basedonproductcharacteristics of knowledge and wisdom. The characteristics of these methods andtheir organic connection between them and put forward to achieve the computerproduct design direction.Key words: Mechanical Product Design MethodDevelopment Trends Design documents will be Semantic Web as a design tool inthe design of its Semantic Web activity of the development of ASK, using nodes andlines to describe the design a network, nodes that components of the cell (such asdesign tasks, functions, components or processing equipment, etc. ), used to adjust thelines and definitions between nodes of different semantic relations, thus the designprocess all the activities and results of pre-built models so that the definition of theearly design requirements to the specific description of each structure can be definedby the relationship between the expression, achieved a computer-aided design process,the leap from the abstract to the concrete.Asystematic design methodThe main features of a systematic design method are: the design as designed by anumber of elements of a system, the independence of each design elements, eachelement of an organic link between the existence of, and is layered, with all the designelements , you can design systems to achieve the required task.Systematic design idea in the 70s by the German scholar Professor Pahl andBeitz, the system based on the theory they developed a general pattern of the design,advocacy design work should have organized. German Engineers Association, on thebasis of this design concept to develop a standard VDI2221 technology systems andproduct development design methods.1.The user needs functional characteristics as a product concept, structuredesign and part design, process planning, job control, etc. based on the macro fromthe product development process of starting the use of quality function deploymentmethod and system to user demand information reasonably and efficiently convertedto the various stages of product development, technical goals and operational controlprocedures method.2.The level of the product life of the organism as a system, and means ofliving systems theory, the product design process can be divided into successfulhierarchy of needs to achieve the functional requirements of the conceptual level andproduct level of the specific design. At the same time life-support systems used toexpress the abstract icons of the product functional requirements, system structureformation of product features.3.The mechanical design of the application of systems science into two basicquestions: First, to be designed as a system dealing with the products, the best way todetermine its component parts (modules) and their mutual relations1; is the productdesign process as a system, according to design objectives, a correct and reasonablydetermine the various aspects of the design work and various design stage.Because each designers point of research questions and to consider the questionof emphasis, to design a specific research methods used is also different. Here aresome representative of the systematic design methods.4.Design Element MethodWith the five design elements (functions, effects, effects vector, shape, elements,and surface parameters) describe the product solutions that a product to determinethe value of the five design elements, the product of all the features and characteristicsof the value of i.e. determined. Scholars in China have adopted similar methodsdesigned to describe the products original understanding.5.Graphic modeling methodAnd developed a design analysis and guidance systems KALEIT, with thelevel of clear graphic description of a products functional structure and its associatedabstract information, to the system structure and function relationship of graphicalmodeling, and functional connection between the layers 2.Assistance will be designed to be divided into two aspects of methodology andexchange of information using the Nijssen Information Analysis Method can be usedgraphic symbols, with a rich semantic model structure, can be described as integrationconditions, can be divided into types of constraints can be achieved in relationsbetween any combination of characteristics , the design method to solve integrationand information technology to realize the design process of information betweendifferent abstraction layers between the graphical modeling.6.Concept - Design methodProducts design is divided into concept and design in two stages. Conceptphase of the task is to find, choose and mix to meet the requirements of the originalunderstanding of design tasks. Design stage of work is a concrete realization of theoriginal understanding of the conceptual stage.Of the programs idea of specific described as: In accordance with theappropriate functional structure, seeking to meet the design requirements of theoriginal understanding of the task. The functional structure of the sub-function isperformed by the structural elements to achieve, and structural elements of thephysical connection between the definition of a feature vector, feature vector andstructural elements further the interaction between the formation of the functionaldiagram ( mechanical diagram). The program design is based on functional diagram,the first qualitative description of all of the feature vector and structural elements,and then quantitatively describe all the structural elements and the connection parts( feature vectors), the shape and location to be structure diagram3. Roper, H. usinggraph theory, by means of which he defines as the total design unit (GE), structuralelements (KE), functional structural elements (FKE), connect structural elements(VKE), Structural Parts (KT), structure element part (KET) concepts, as well asdescribe the structure element size, location, and transmission parameters of theinteractions between a number of kinds of schematics, the intuitive designprofessionals have done a formal design method a description of the formation of aneffective application of existing knowledge, methods, and applied to ideas anddesign stage.7.Bond Graph MethodFunction of the composition of system components will be divided into produceenergy, consumed energy, changing energy forms, such as various types of energytransfer, and to use bond graphs to express the function component solution, hoping tofunction-based model and bond graph combine to achieve functional structure theautomatic generation and functional structure with the bond graph automaticconversion between the search for bond graph generated by a number of designmethods.To promote the product on the basis of functional analysis, the product has somefeatures broken down into one or several modular basic structure, by selection andcombination of the basic structure of these modular form into different products.These basic structures can be parts, components, or even a system.The structure should have a standardized interface (connection and co-operationdepartment),andisserialized,universal,integrated,hierarchical,agile,economic-oriented, with interchangeability, compatibility and relevance. Chinascombination of software component technology and CAD technology, variant designcombined with the modular design, according to modular principle of classification,will be divided into descending Machining Center Machine Tool product level,component level, component level and component level, and use expert knowledgeand CAD technology to combine them into different species, different specificationsof functional blocks, and then by the combination of these functions into differentmodules of the overall program processing center.To design a directory as an alternative variation of the mechanical structure ofthe tool, the solution proposed by the design elements of a complete, structured layout,the formation of the solution set design catalogs. And in the solution set designed tocomment on each one listed in the directory solution additional information, is verybeneficial to design engineers select solution elements.The vigorous development of network technology, collaborative design andmanufacturing, as well as the product from the users functional requirements design processing assembly finished product of this realization of concurrentengineering possible. However, an important prerequisite to achieve these goals oneof the conditions is to realize the effect of product design three-dimensionalvisualization. To this end, three-dimensional graphics software, more and moreintelligent design software programs used in the product design, virtual realitytechnology and multimedia, hypermedia tools for product design is also its first debut.At present, Germany and other developed countries are focused on researchhypermedia technology, product data exchange standard STEP, as well as standardvirtual reality modeling language based on a standard exchange format for virtualenvironments) in the product design applications.Mechanical product design is moving in computer-aided realization of intelligentdesign and to meet the needs of distributed collaborative design and manufacture ofdirection, due to the computer product design Study on the implementation startedlate, not yet mature, to achieve the above objectives program design tools4. Authorbelieves that the integrated use of paper, four types of design method is an effectiveway to achieve this goal. Although the integrated use of these methods are moreinvolved in the field, not only with the mechanical design of the field-relatedknowledge, but also to the systems engineering theory, artificial intelligence theory,computer hardware and software engineering, network technology areas such asdomain knowledge, it is still product design must be working for. Abroad in researchin this area has achieved initial success, our scholars have been aware of CAD designtechnology and the importance of international exchange and cooperation, and itsmeasures to be taken.Feature-based design methodology of knowledge The main features are: using acomputer can identify the language to describe the characteristics of the product andits design experts in the field of knowledge and experience to establish the appropriateknowledge base and inference engine, re-use of stored domain knowledge and theestablishment of the inference mechanism to bring computer-aided product design.The mechanical system design is mainly based on the characteristics of a product,and design experts in the field of knowledge and experience to push volume anddecision-making, the completion of body type, the number of synthesis. To achievethis stage of computer-aided design, must study the automatic acquisition ofknowledge, expression, integration, coordination, management and use. To this end,the design and scholars at home and abroad program for the mechanical systemdesign knowledge of the automated processing done a lot of research work, theapproach can be summarized into the following several.
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