轻型货车后驱动桥设计

喜欢就充值下载吧。。资源目录里展示的文件全都有，，请放心下载，，有疑问咨询QQ:1064457796或者1304139763 ==================== 喜欢就充值下载吧。。资源目录里展示的文件全都有，，请放心下载，，有疑问咨询QQ:1064457796或者1304139763 ==================== 任务书 专业 班级 学生 设计题目 轻型货车后驱动桥设计 课题来源 起讫日期 年 月 日至 年 月 日 指导教师（签名） 教研室主任（签名） 课题依据 一、相关整车参数 　　　1.汽车满载质量3720KG 前轴1380KG 后轴2340KG 　　　2.整载质量2700KG 　　　3.主减速比6.28 　　　4.变速器比5.568 2.832 1.634 1.00 0.75 倒挡4.79 　　　5.发动机最大功率75KM/2900rpm 　　　6.最大转距190.8N.M/1700-1800rpm 二、参考文献 1.《汽车设计》，刘惟信，清华大学出版社； 2.《机械设计手册》，第三版，第1、2卷； 3. GB/T7258—2004《机动车运行安全技术条件》。 任务要求： 1.绘制后驱动桥包括前、后，右等方向视图和必要的剖视图，要有零件图。图纸要符合相关标准。工作量不少于2张半零号图纸。 2.编写设计计算说明书，字数不少于8000，并有中英文摘要。 3.翻译不少于3000外文字符的相关外文资料。 4.提交不少于3000字的调研报告或资料综述。 设计进度计划 起讫日期 工 作 内 容 备 注 3.24～3.31 4.1～4.15 4.16～5.10 5.11～6.31 6.1～6.5 6.6～6.14 熟悉课题，收集资料 翻译外文资料，撰写资料综述或调研报告 确定方案，设计计算，绘制草图 绘制总装图及零件图 撰写说明书 完成论文PPT，准备答辩 备注 4 外文文献原文： Drive axle is one of the important bearing automobile assembly, the property can directly affect the vehicle performance and service life. Driving bridge like a bridge shell, the main reducer, differential and half shell and other components, turn to drive the bridge also includes a variety of constant velocity coupling,The structure is more complex.The traditional design is based on the production experience as the foundation, using mechanical, number and the regression formula, formation of charts, manuals for the modern design is the traditional design of deep, rich and the development, rather than the new design independent from the traditional design. The computer technology as the core the heart, in order to design theory as the guide, is a main character of modern design. Using this method to guide the design can reduce the blindness of design and experience arbitrariness, improve the initiative, scientific and accurate design.Similarly, research on the driving axle should not only stay in the traditional design .Method, but with the aid of the modern design method to refine on. This the research on driving modern design method of bridge to do more deep.In the study, the various design methods with each other, according to different design content separately using different method, in order to promote its design.History tends to be more reasonable and scientific 1CAD/CAE Technology CAD is the use of computer system in the engineering and product design.Each stage provides a variety of fast, effective tools and designers.Means, to accelerate the optimization and design process and design results,in order to achieve the best design technology. The application of CAD technology in mechanical products design meter, which can not only shorten the design cycle, but also can improve the precision of the design and reliability, so as to realize the optimization and automation of the design process.The development of an open, integrated and intelligent trend.At present, the 3D CAD modeling software commonly used with Pro/E, UG,MDT, Solid Works, Auto CAD etc.. Pro/E is a kind of CAD/CAE/CAM software system integration, with a strong practical body shape and surface modeling function, can be constructed very complex models. The resulting model can form assembly, and can generate the model zero Mold. Whether the part model, assembly model or die type, can be transformed into the two-dimensional engineering drawings. It uses a single database,The corresponding data can automatically modify the stage at any stage.Finite element technology in CAE is a mathematical calculation, calculation of the force Science and Engineering Science, born in the most effective calculation method. Form the enriched finite element method, a theoretical basis for improving, and have a general finite element program, the use of these software can solve large scale science and engineering computation problem of numerous,finite element calculation The fruit has become the design and performance analysis of all kinds of industrial products reliable basis. According to. Many finite element analysis program of the finite element analysis, computer graphics study and optimization technology together, form a computer aided complete analysis of the system, can significantly improve the performance of product design, shorten the design cycle Period, enhance the competitiveness of products.In many finite element analysis software, ANSYS is the most general One of the effective software, it has enriched and improved cell library,material model base and solver, ensure efficient solving the structural static force, force, vibration, linear and nonlinear problems and thermal analysis and structure coupling problem, the advanced analysis techniques can be parameterized The design, optimization and topology optimization. CAD/CAE technology is big in the research and design of driving axle play. For new products, using CAD to create the drive axle of each element The entity model, the model is calculated by CAE, test Its performance meets the requirements. If you don't meet the requirements can modify the model type, until satisfied. Finally the model into the engineering diagram, can manufacturing products. If the CAD/CAE and CAM or rapid prototyping technology combined, can significantly shorten the production from design to manufacturing product cycle, parts library can also generate existing parts, in order to facilitate the similar or the design of series of drive axle. Of course, the strength and the existing parts Failure analysis and improvement are also often used this method In the analysis of a mini car special damage reason of drive axle housing, Reference [1] by using the CAD/CAE method. We use the 3-D CAD modeling software De as to build the bridge shell model, then there is The finite element method to calculate, found that local stress concentration occurs, the regional and regional anastomosis failure. Using different ways to fix the model Instead, the modified model and calculate the stress distribution, find a good change good plan. Improved drive axle used in good condition. Reference [2] CAD/CAE technology and C language combination, using C language in the "class" of the system control module and the function module elements and package member function, the optimal range of drive axle product data model, to maximize the use of existing design resources. 2Reliability Engineering Reliability engineering is based on probability and stochastic distribution,research structure in the requirements and within the time specified, complete function probability. Research on stochastic phenomenon long-standing, but in its work The application process is not accompanied by. The traditional design that the material Body performance (strength, toughness and hardness) and the stress is a constant, in order to guide product conservative. Considering the randomness and reliability is introduced in the design, to reflect the objective reality, Thus the design of products is also more scientific, reasonable. Now, some developed Some parts of the country of design and manufacture, the life can be accurate to hours, If there is no reliability calculation, is unthinkable.The calculation method of reliability of mechanical structure commonly used is a two order moments method. The state function (strength and stress difference on the mean point)Expansion in Taylor series, ignoring the more than two times, we can get the reliability Index. The method assumes that all variables are normal independent of each other random variable, linear and only from the series, so with the actual deviation is Big. Therefore, people also improved the method, get the design checking point method, equivalent normal distribution method and the Lagrange multiplier method [3]. In recent years With the development of fuzzy mathematics, and finite element method, the fuzzy A new method of reliability based design and finite element reliability calculation, The calculation of the reliability is also a semi empirical and semi probabilistic method, approximate probability Method to the development of the full probability method is more accurate.In order to make the performance of drive axle is more excellent, more in line with people's life The requirements, including the design of half axle to axle, gear must be reliable Degree of consideration. In the reference [4], in order to achieve a reliable The drive axle housing of inner diameter, the late Bias statistical expectation Methods were summarized, the drive axle based on Bayesian statistics Reliability design of shell, and verified by examples. The results show that This method overcomes the shortcomings of the traditional method conservation, make the design more reasonable.Reference [5] introduces a reliability design in driving axle main reducer In the design, the main reducer single-stage Wheeled Construction Machinery The reliability optimization mathematical model and example analysis, the method To reduce the driving bridge size, save and improve the carrying capacity and the use of materials The conclusion has great practical significance of life. 3Modal analysis Modal analysis is a structural study of the vibration analysis One of the modern methods and means of advanced. It can be defined as the structure Analysis of the dynamic characteristics of the (finite element analysis) and experimental analysis (real Experimental modal analysis, the structural dynamic characteristics) using modal parameters to characterize the. In mathematics, the modal parameters are the differential equations of motion for mechanical systems The eigenvalues and eigenvectors; while in the experimental aspect, is measured Pole (natural frequency and damping) and the mode (modal vector). Modal analysis of characteristics and advantages of technology in power system Analysis, modal coordinates instead of physics coordinate, thereby greatly The number of degrees of freedom compression system analysis, analysis of high precision. For A large and complex system, such as cars, the sub structure analysis Method. It is the large structure complex for all sub structure, respectively Analysis of the finite element analysis and experimental modal substructure,get sub The dynamic model and the characteristic parameters of the structure, the sub structure according to the Methods to analyze integrated into a whole, is an effective reduction of self By the method of. Vibration characteristics of driving axle affects not only its own strong Degree, but also on the vehicle's ride comfort is important Influence. Therefore, drive on the bridge for the modal analysis, control and improve the Vibration characteristics, is one of the most important aspects in the design of. Reference [6] found a car through the modal analysis method Damage reason of drive axle. The car used in the central area of the drive axle housing Domain often cracks, calculations show that the bridge shell static stress distribution static strength Reasonable, destroy the static stress is small. Modal analysis of bridge shell Nine frequencies in the frequency range of the road spectrum, road surface spectrum excitation It is easy to cause resonance in the vertical direction. Forced vibration further divided The analysis results show, wherein certain parts of stress strength of materials is more than Limit, dynamic characteristics, dynamic strength is not good enough is generated to drive the bridge damage The fundamental reason. It not only shows the modal analysis method in the study of driving bridge With the application and design, but also the necessary. Because The traditional design and analysis method is not enough to solve the key components of a vehicle moving The strength state bearing. 4Modern optimization algorithms Modern optimization algorithms including neural network, ta bu search algorithm, die simulated annealing algorithm, genetic algorithm and Lagrange relaxation algorithm. This Some algorithms involved in biological evolution, artificial intelligence,mathematics and physics, God The system and statistical mechanics concepts, is a visual based the algorithm, called heuristic algorithm. The heuristic algorithm A close relationship with the formation of the theory of computational complexity. When people do not Satisfied with the conventional algorithm for solving complex problems,modern optimization algorithms began to reflect its role. Simulated annealing algorithm local search algorithm is extended, it is a global optimization algorithm, which can be applied to combinatorial optimization problems. Genetic algorithm is a random global search algorithm, the search automatic acquisition and accumulation of knowledge of space cable in the process, and the adaptive We should control the search process, so as to obtain the optimal or suboptimal solution. By in the genetic algorithm has the compatibility, it can be in accordance with the genetic algorithm and model The advantages of simulated annealing algorithm respectively, the combined tectonic genetic model Simulated annealing algorithm, multi objective of discrete and continuous design variables optimization design. In addition, the fuzzy mathematics and optimization is a combination of fuzzy optimization The algorithm, combined with the reliability engineering and Optimization Based on the reliability of the optimization algorithm. Can be expected, with the development of science and technology, the inevitable There will be new optimization algorithms, more advanced various. The design of the optimization algorithm is introduced and the components of the drive axle, can reduce component size, material saving, optimal transmission structure,optimization of transmission part parameters, make the design more scientific, reasonable. Reference [7]and [8] respectively with neural network, genetic algorithm for straight tooth and bevel gear transmission dynamic optimization, the objective function is the minimum volume of gear pair, reach satisfactory results. This shows that the driven application optimization algorithm Bridge structure of transmission parts size optimization design is feasible,efficient. 译文： 驱动桥是汽车总成中的重要承载件之一,其性能直接影响整车的性能和有效使用寿命。驱动桥一般由桥壳、主减速器、差速器和半壳等元件组成,转向驱动桥还包括各种等速联轴节,结构更复杂。传统设计是以生产经验为基础,以运用力学、数学和回归方法形成的公式、图表、手册等为依据进行的。现代设计是传统设计的深入、丰富和发展,而非独立于传统设计的全新设计。以计算机技术为核心,以设计理论为指导,是现代设计的主要特征。利用这种方法指导设计可以减小经验设计的盲目性和随意性,提高设计的主动性、科学性和准确性。同样,对驱动桥的研究不应仅停留在传统设计方法上,而应借助于现代设计方法以精益求精。本文对研究驱动桥所涉及的现代设计方法做了比较深入的研究,提出将各种设计方法互相结合,针对不同的设计内容分别应用不同的方法,以促进其设计过程趋于合理化和科学化。 1　CAD/CAE技术 CAD是利用计算机系统在工程和产品设计的各个阶段为设计人员提供各种快速、有效的工具和手段,加快和优化设计过程及设计结果,以达到最佳设计需要的技术。将CAD技术应用于机械产品设计,不但可以缩短设计周期,还可以提高设计的精确度和可靠性,从而实现设计过程的最佳化和自动化。其发展呈开放、集成及智能的趋势。目前常用的三维CAD造型软件有Pro/E、UG、MDT、Solid Works、AutoCAD等。Pro/E是一种CAD/CAE/CAM一体化的软件系统,具有强大的实体造型和表面造型功能,可构造非常复杂的模型。产生的模型可形成装配体,并能生成制造该模型零件的模具。无论零件模型、装配体模型还是模具模型,都可转化为二维工程图。它采用单一的数据库,在任何阶段都能自动修改各阶段的相应数据。CAE方法中的有限元技术是计算数学、计算力学和计算工程科学领域里诞生的最有效的计算方法。有限元方法形态丰富,理论基础完善,且已经开发出一批通用有限元程序,使用这些软件可解决工程领域众多的大型科学和计算难题,有限元计算结果已成为各类工业产品设计和性能分析的可靠依据。许多有限元分析程序将有限元分析、计算机图形学与优化技术结合起来,形成完整的计算机辅助分析系统,可显著提高产品设计性能,缩短设计周期,增强产品的竞争力。在众多有限元分析商业软件中,ANSYS是最通用有效的软件之一,它拥有丰富和完善的单元库、材料模型库和求解器,确保高效地求解各类结构的静力、动力、振动、线性和非线性问题以及热分析和热-结构耦合问题,其高级分析技术还能进行参数化设计、优化设计和拓扑优化等。CAD/CAE技术在驱动桥的研究和设计中大有用武之地。对于新产品,用CAD造出驱动桥各个元件的实体模型,用CAE对这些模型进行计算,检验其性能是否满足要求。如果不满足要求可修改模型,直到满意为止。最后将模型转化为工程图,便可制造产品。如果将CAD/CAE与CAM或快速成型技术结合起来,能显著缩短从设计到制造的整个产品周期,还可生成现有零件的零件库,以方便相似或系列驱动桥的设计。当然,对已有零件进行强度和失效分析以及改进也会经常用到这种方法。在分析某微型车专用驱动桥壳的破坏原因时,参考文献[1]采用了CAD/CAE方法。先用三维CAD造型软件Deas建造该桥壳的模型,然后用有限元方法进行计算,发现局部区域出现应力集中,该区域与破坏区域吻合。采用不同方案对模型进行修改,并计算修改后模型的应力分布,找到了较好的改善方案。改进后的驱动桥使用情况良好。 参考文献[2]则将CAD/CAE技术与C语言相结合,利用C语言中的“类”对系统控制模块和功能模块元素及成员函数进行封装,得到优化的系列驱动桥产品数据模型,最大限度地利用了现有设计资源。 2　可靠性工程 可靠性工程以概率和随机分布为基础,研究各种结构在规定条件和规定时间内,完成规定功能的概率。人们对随机现象的研究由来已久,但其在工程中的应用却并非相伴而生。传统设计认为材料本身的性能(强度、韧性和硬度等)和所受到的应力都是常量,以此为指导的产品偏于保守。考虑随机性并在设计中引入可靠度,更真实地反映了客观现实,由此设计出的产品也更科学、合理。现在,一些发达国家设计制造的某些零件,其寿命可以精确到小时,如果没有可靠性计算,是不可想象的。机械结构常用的可靠度计算方法是一次二阶矩法。该法将状态函数(强度与应力之差)在均值点处按泰勒级数展开,忽略二次以上项,便可得到可靠度指标。由于该法假设各个变量均为相互独立的正态随机变量,且只取级数的线性项,故与实际偏差较大。为此,人们又改进了这种方法,得到设计验算点法、等效正态分布法和拉格朗日乘子法等[3]。近年来,随着模糊数学和有限元技术的发展,出现了模糊可靠度设计和基于可靠度的有限元计算等新方法,可靠度本身的计算也由半经验半概率法、近似概率法发展到更精确的全概率法。 为了使驱动桥的性能更优良,寿命更符合人们的要求,包括桥壳、齿轮到半轴的设计都必须将可靠度考虑进去。在参考文献[4]中,为了实现给定可靠度求出驱动桥壳内径,作者对贝叶斯统计后期期望方法进行了整理,得到了基于贝叶斯统计的驱动桥壳的可靠性设计,并通过例子予以验证。结果表明该方法克服了传统方法的保守性,使设计更合理。参考文献[5]介绍了可靠性设计在驱动桥主减速器设计中的应用,给出了单级轮式工程机械主减速器的可靠性优化数学模型和算例分析,得出了该方法对减小驱动桥尺寸、节省材料、提高承载能力和使用寿命具有较大实际意义的结论。 3　模态分析 模态分析是对工程结构进行振动分析研究的最先进的现代方法与手段之一。它可以定义为对结构动态特性的解析分析(有限元分析)和实验分析(实验模态分析),其结构动态特性用模态参数来表征。在数学上,模态参数是力学系统运动微分方程的特征值和特征向量;而在实验方面,则是测得的系统的极点(固有频率和阻尼)和振型(模态向量)。模态分析技术的特点与优点是在对系统做动力学分析时,用模态坐标代替物理学坐标,从而可大大压缩系统分析的自由度数目,分析精度较高。对于大型复杂的系统,比如汽车,可采用子结构分析方法。它是把复杂的大型结构划分为各子结构,分别对子结构进行有限元分析或实验模态分析,取得子结构的动力模型及其特性参数,再将子结构按照一定方法综合成一整体进行分析,是一种有效缩减自由度的方法。驱动桥的振动特性不但直接影响其本身的强度,而且对整车的舒适性和平顺性有着至关重要的影响。因此,对驱动桥进行模态分析,掌握和改善其振动特性,是设计中的重要方面。参考文献[6]通过模态分析方法找到了某汽车驱动桥的破坏原因。该车使用中其驱动桥壳中部区域常出现裂纹,静强度计算表明该桥壳静应力分布合理,破坏区的静应力很小。模态分析中桥壳的前九阶频率在路面谱频率范围内,在路面谱的激励下很容易引起垂直方向的共振。进一步的强迫振动分析表明,其中部某些部位应力超过了材料的强度极限,动态特性不好、动强度不足是产生驱动桥破坏的根本原因。这不但说明模态分析方法在驱动桥研究和设计中有着具体的应用,而且还是必要的。因为传统设计和分析方法不足以解决汽车关键部件的动态承载强度问题。 4　优化算法 现代优化算法包括神经网络、禁忌搜索算法、模拟退火算法、遗传算法和拉格朗日松弛算法等。这些算法涉及生物进化、人工智能、数学和物理学、神经系统和统计力学等概念,是以一定的直观为基础构造的算法,称之为启发式算法。启发式算法的兴起与计算复杂性理论的形成有密切关系。当人们不满足于常规算法求解复杂问题时,现代优化算法开始体现其作用。模拟退火算法是局部搜索算法的扩展,它是一种全局最优算法,可应用于组合最优化问题。遗传算法是一种随机的全局搜索算法,能在搜索过程中自动获取和积累有关空间的知识,并自适应地控制搜索过程,从而得到最优解或次优解。由于遗传算法具有兼容性,因此可根据遗传算法和模拟退火算法各自的优点,将两者相结合构造遗传模拟退火算法,对离散与连续的设计变量进行多目标优化设计。另外,模糊数学和优化相结合产生了模糊优化算法,可靠性工程和优化的结合则产生基于可靠性的优化算法。可以预见,随着科学技术的发展,必然会出现各种新型的、更先进的优化算法。将优化算法引入驱动桥及各元件的设计,可以减小部件体积、节省材料、优化传动结构、优化传动零件的参数,使其设计更科学、合理。参考文献[7]和[8]分别用神经网络、遗传算法对直齿和斜齿轮传动进行了优化,以齿轮副体积最小为目标函数,达到了令人满意的结果。这表明应用优化算法进行驱动桥传动零件结构尺寸优化设计可行、高效。 参考文献: [1]　陈效华.基于有限元方法的微型汽车驱动桥结构分析[J].中国制造业,2003,32(4). 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