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理工科类本科生毕业设计（论文）开题报告论文(设计)题目纯电动跑车变速箱设计作者所在系别机电工程作者所在专业车辆工程作者所在班级B13142作 者 姓 名郑廷芸作 者 学 号201322198指导教师姓名白亚双指导教师职称讲师完 成 时 间2017年3月北华航天工业学院教务处制说 明1根据学校毕业设计(论文)工作暂行规定，学生必须撰写毕业设计（论文）开题报告。开题报告作为毕业设计（论文）答辩委员会对学生答辩资格审查的依据材料之一。2开题报告应在指导教师指导下，由学生在毕业设计（论文）工作前期内完成，经指导教师签署意见及所在专业教研室论证审查后生效。开题报告不合格者需重做。3毕业设计开题报告各项内容要实事求是，逐条认真填写。其中的文字表达要明确、严谨，语言通顺，外来语要同时用原文和中文表达。第一次出现缩写词，须注出全称。4开题报告中除最后一页外均由学生填写，填写各栏目时可根据内容另加附页。5阅读的主要参考文献应在10篇以上（土建类专业文献篇数可酌减），其中外文资料应占一定比例。本学科的基础和专业课教材一般不应列为参考资料。6参考文献的书写应遵循毕业设计（论文）撰写规范要求。7开题报告应与文献综述、一篇外文译文和外文原文复印件同时提交，文献综述的撰写格式按毕业设计（论文）撰写规范的要求，字数在2000字左右。毕业设计(论文)开题报告学生姓名郑廷芸专 业车辆工程班 级B13142指导教师姓名白亚双职 称讲师工作单位课题来源课题性质课题名称纯电动跑车变速箱设计3本设计的科学依据（科学意义和应用前景，国内外研究概况，目前技术现状、水平和发展趋势等） 随着石油资源的日益减少和环境保护要求的提高，电动汽车的发展越来越受到人们的重视，然而，对动力传动系统部件的设计参数进行研究是提高电动汽车性能的重要手段之一。变速器是汽车重要的传动系组成，在较大范围内改变汽车行驶速度的大小和汽车驱动轮上扭矩的大小。 电动汽车的变速器与普通变速器相比，其结构有所不同。因为驱动电机的旋向可以通过电路控制实现变换，所以电动汽车无需内燃机汽车变速器中的倒档而设置倒档轴，只需应用电机反转来实现倒车行驶。设计中利用已知参数确定变速器各参数，对轴和各挡齿轮进行校核，绘制出装配图及零件图。 同时本设计对电动汽车的动力传动系统进行了匹配设计计算，计算结果表明达到性能要求。设计内容和预期成果（具体设计内容和重点解决的技术问题、预期成果和提供的形式）1）传动机构布置方案分析 变速器传动机构有两种分类方法。根据轴的形式不同，分为固定轴式和旋转轴式（常配合行星齿轮传动）两类。固定轴式又分为两轴式，中间轴式双中间轴式变速器。固定轴式应用广泛，。其中两轴式变速器多用于发动机前置前轮驱动的汽车上。中间轴式变速器多用于发动机前置后轮驱动的汽车上。旋转轴式主要用于液压机械式变速嚣。与中间轴式变速嚣比较，两轴式具有结构简单，轮廓尺寸小，布置方便。此外，因为其经过一对齿轮啮合传动动力，故传动效率高同时噪音低。三轴式变速嚣与两轴式相比各档多了一对齿轮传动因而传递效率低噪音大。所以选择本设计两轴式双挡变速器。2）变速其主要参数选择（l）挡数 增加变速器的档数能改善汽车的动力性和经济性，挡数越多，变速器的结构越复杂，并且是尺寸轮廓和质量加大同时操纵机构复杂，而且在使用时换挡频率也增高由于电动汽车的发展起步晚，受技术限制所以选用两挡变速箱，倒挡由电机反转来实现。 (2)传动比范围 变速器的传动比范围是指变速器最低档传动比与最高档转动比的比值传动比范围的确定与选定的发动机参数，汽车的最高车速和使用条件等因素有关。 (3)中心距A 对两轴式变速器，输入轴与第二轴之间的距离称为变速器中心距，其大小不仅对变速器的外形尺寸，体积和质量大小，而日对轮齿的接触强度有影响。中心距越小，齿轮的接触应力大，齿轮寿命短。最小允许中心距当有保证齿轮有必要的接触强度来确定。（4）各档齿轮齿数的分配 在初选中心距，齿轮模数和螺旋角以后可更据变速器的挡数，传动比和传动方案来分配各档齿轮的齿数。两档变速器为例，说明分配齿数的方法尽可能使各档齿轮的齿数比应该不是整数。3)变速器的设计与计算 (1)齿轮的损环形式 轮齿折断，齿面疲劳剥落，移动换挡齿轮端部破坏， 轮齿折断分两种：轮齿受足够大的冲击载荷作用，造成轮齿弯曲折断；轮齿再重复载荷作用下齿根产生疲劳裂纹，裂纹扩展深度逐渐加大，然后出现弯曲折断。前者在变速器中出现的很少，后看出现的多。（2)齿轮强度计算 与其他机械行业相比，不同用途汽车的变速器齿轮使用田间仍是相似的。此外，机车变速器齿轮用的材抖，热处理方法，加工方法，精度级别，支承方式也基本一致。如汽车变速器齿轮用低碳钢制作，采用剃齿与磨齿精加工，齿轮表面采用溶碳淬火热处理工 艺，齿轮精度为JBI79-83，6级和7级。4）轴承的选择 变速器轴承常采用圆柱滚子轴承，球轴承，滚针轴承，圆锥滚子轴承，滑动轴套等。至于何处应当采用何种轴承，是受结构限制并随所承受的载荷特点不同而不同。 汽车变速器结构紧凑，尺寸小，采用尺寸大些的轴承结构受限制，常在布置上有困难。如变速器的第二轴前端支承在第一轴常啮合齿轮的内腔中，内腔尺寸足够时可布置圆柱滚子轴承，若空间不足则采用滚针轴承变速器笫一轴前端支承在飞轮的内腔里，因有足够大的空间常采用球轴承来承受向力。5)变速器操纵机构 根据汽车使用条件的需要驾驶员利用变速器的操纵机构完成选挡和实现换挡或退到空挡的工作。 变速器操纵机构应当满足如下主要要求：换挡时只能挂入一个挡位，换挡后应使齿轮在全齿长上啮合，防止自动脱挡或自动挂挡，防止误挂倒挡，换挡轻便。用于机械式变速器的操纵机构，常见的是由变速轩，拨块，拨叉、变速叉轴及互锁、自锁和倒挡锁装置等主要件组成，并依靠驾驶员手力完成换挡或退到空挡工作，称为手动换挡变速器。 本科生毕业设计(论文)文献综述设计 (论文)题目纯电动汽车变速箱构设计作者所在系别机电工程作者所在专业车辆工程作者所在班级B13142作 者 姓 名郑廷芸作 者 学 号201322198指导教师姓名白亚双指导教师职称讲师完 成 时 间2017年3月北华航天工业学院教务处制说 明1根据学校毕业设计(论文)工作暂行规定，学生必须撰写毕业设计(论文)文献综述。文献综述作为毕业设计(论文)答辩委员会对学生答辩资格审查的依据材料之一。2文献综述应在指导教师指导下，由学生在毕业设计(论文)工作前期内完成，由指导教师签署意见并经所在专业教研室审查。3文献综述各项内容要实事求是，文字表达要明确、严谨，语言通顺，外来语要同时用原文和中文表达。第一次出现缩写词，须注出全称。4学生撰写文献综述，阅读的主要参考文献应在10篇以上（土建类专业文献篇数可酌减），其中外文资料应占一定比例。本学科的基础和专业课教材一般不应列为参考资料。5文献综述的撰写格式按毕业设计(论文)撰写规范的要求，字数在2000字左右。文献综述应与开题报告同时提交。毕 业 设 计（论 文）文 献 综 述摘要变速器是汽车传动系统结构中最重要的部分之一，汽车的前进、后退，增速、减速都要靠变速器传动来实现。而且变速器在汽车动力性和燃油经济性上也有重要的影响。本设计的电动赛车变速器，主要任务是完成齿轮、轴、箱体等的设计及校核，和位置的确定，并满足其承载能力的同步器。另外，针对齿轮作用力的不同，可以在不同的轴上选择合适的轴承。利用AUTCAD完成变速器的总成图、第一轴、第二轴、中间轴、各个挡齿轮及同步器的设计。随着我国汽车行业的迅猛发展，人们对汽车的需求也越来越高。通过对载货汽车变速器的设计我了解到变速器在汽车结构中具有着重要的作用。变速器结构的改进对汽车行业的发展与进步具有着深远的意义。关键词：纯电动汽车 零排放 蓄电池AbstractTransmission is the most important part in transmission agent in an auto. The reason is that forward, backward, speed up, slowdown and other manipulate of auto have to be completed by transmission. And transmission is also important in Automotive dynamica perform and fuel economy. The main purpose of this design-电动赛车 gearbox is to complete the design, check and position among gears, axles, case, and this design should have enough capability. In addition, it can choose an appropriate bearing, which based on the different gears forces. We can complete this design, primary shaft, secondary shaft, intermediate shaft, any gear, and synchro by AUTCAD.With the rapid development of Chinese automobile industry, people has more and more demands in autoes. To design this transmission of van; I realized that transmission is very important in vans conformation. The developed of transmission is profound for growth and progress of autoes.Key words: Electric Vehicle, Zero Emissions, Battery1.电动汽车的发展概况从汽车发展的历史来看电动汽车(EV，Electric Vehicle)其实比燃油汽车还要早诞生几年，但受电池和驱动控制技术的局限，其发展却远远落后于燃油汽车。本世纪六七十年代，电动汽车开始复苏。现在随着电力电子、控制、材料等技术的发展在世界各国激发了研究、开发、应用电动汽车的热潮，可以预见电动汽车将是21世纪的重要交通工具。国外的发展状况，德、日、法、美这几个汽车工业发达国家，到目前为止都已研制出实用的电动汽车，其中包括大客车、轿车、摩托车等。美国几大主要汽车制造商已广泛深入的开展了电动车的研究。其中通用汽车公司是电动汽车行业的领导者。通用与美国能源部合作，用MH-Ni电池取代铅蓄电池，使电动车一次充电行使距离达到160km，他们计划在2004年开始生产燃料电池的电动汽车。1991年美国三大汽车公司签订协议，合作研究电动汽车用先进电池，成立先进电池联合体。同年7月美国电力研究院参加了美国先进电池联合体，10月布什总统批准了226亿美元拨款资助此项研究。福特汽车公司投资15亿英磅开发电动汽车，1993年研制成功，现已生产81辆，分赴美国各地进行试运行，采用480个钠硫单元电池，取代原来的铅酸蓄电池。通用汽车公司1990年在洛杉矶展出“冲击”电动骄车，1994年生产50辆。1991年1月美国电力研究院，1995年美电力研究院、克莱斯勒公司与南加州爱迪生公司共同开发50辆电动货车。1995年3月统计数据，美国现有190家电动汽车生产企业，共有电动汽车2000多辆。日本东京电力公司1988年联合日本电池公司共同开发TZA电动汽车，体现了当时最新技术水平，空载量1573kg，装有288v镍镉电池，四台直流无刷电机，输出功率为100kW,最高车速176km/h。法国标致一一一雪铁龙与雷诺两大汽车公司一直在积极研制，1990年的J-5和C-25电动货车投入生产，1995年将标致106和雪铁龙AX电动车投入生产。法国能源部、标致一一一雪铁龙公司和罗切里市签订协议从1993年9月开始，该市试用标致106和雪铁龙AX改装的电动轿车各25辆，并在市建9个公共地面充电站，3个快速充电站，1994年7月50辆电动轿车己行驶32.7万公里，法国政府计划在巴黎等27个城市中继续推广电动车。德国早在1900年波许公司就生产早期的电动汽车。1972年开始欧宝公司研制电动汽车，1981年与ABB公司合作改装电动车。80年代初期奔驰生产电动大客车，至今还有十辆在运行中。德国政府科技部资助17亿马克开发电动汽车，19m年科尔州将300辆电动汽车投入运行，德国奔驰、大众两大汽车集团合资建立开发机构。其他国家和地区如丹麦、奥地利、捷克、匈牙利、俄罗斯、澳大利业、墨西哥等都在开展和研制电动汽车。特别值得关注的是业洲许多新发展国家和地区，近30年来经济发展迅速，人民生活提高很快，80年代中国香港从欧洲及日本进口15辆电动汽车，1983年香港政府通过规定，免除电动汽车的首次登记税，即电动汽车价格为燃油车二倍时也与燃油车价格相当；泰国每月出售500辆电动三轮车；马来西业1995年投产；中国台湾1987年开始中华汽车公司外销电动车。业洲电动汽车发展的前景令人乐观。我国电动汽车发展状况。本世纪40年代重庆进行过电动汽车的研究与试验，条件所限未能实现。1958年研制工作半途而废，在1962年上海公用事业研究所进行蓄电池微型汽车研究，制成SWD-S2电动汽车满载量为968Kg，电机功率为25，蓄电池比能量为23.8Wh/kg。行驶车速达到284km/h。一次充电持续行程为82.8km，实际运行了几千公里。电池循环寿命达110次，当时该车每百公里耗电费为1.95元，蓄电池折旧费为8.6元。当时汽油车每公里汽油消耗费为3.65元，由于蓄电池技术没过关，寿命太短，不得不终止。在70年代，研究锌空气电池与钠硫电池没有取得实质性进展，80年代在北京、天津、上海、洛阳、武汉、杭州、珠海等地研制电动汽车，12月成立了中压电工技术学会电动车辆研究会，组织了多次学术交流，起了一定推动作用。我国己经研制成多辆电动汽车，己列入国家计委“八五”项目的清华大学研制电动中型面包车，四川内江“中山湖”电动微型汽车新宁汽车厂电动敞篷轿车，拖拉机研究所LY5010EC电动轿车，珠海伟达电动轿车，郑州华联机场电动牵引车及HL-42轿车投入市场，长江动力公司双层电动大客车，中压远望总公司1990年开始与北京理工大学、国防科技大学、河北胜利客车厂及北京市电车公同联合对电动汽车进行了调研与深入论证，关键技术大功率交流感应电动机驱动控制部分从美国合作引进，1996年在首都北京亮相两辆美观大客车。发展电动汽车要从实际出发，根据我国实际能达到行驶车速达50-70km/h，一次充电续驶里程达100km，单价为燃油汽车的两倍左右。有五种车辆有广泛的发展前途：城市大中型公共客车；机场摆渡车；城市公用事业服务车，如清洁车；中小型商业送货车；游览场所观光游览车，高尔夫球车等。也可以搞一些上述用途的豪华型客车。2电动汽车发展而临的问题：对于纯电动汽车而言，其电池需要满足较高的要求，包括高比能量、高比功率、快速充电和具有深度放电功能、循环和使用寿命长等“目前的电池一方而充电时间较长（在家充电需8-10小时），另一方面一次充电的行驶里程偏短，需要像建加油站那样建设相当一批充电站，因此无法实现商业化量产。在各种车用电池中，铅酸电池是比较成熟的技术，具备较高的性价比和高倍率放电，是目前唯一能大批量生成的电动汽车用电池，但是其比能量、比功率和能量密度都比较低镍镉电池和镍氢电池虽然性能好于铅酸电池，但是其性价比不高，含重金属，用完遗弃后对环境会造成严重污染。锂离子动力电池的工作电压和比能量较高，并且具有体积小、质量轻、循环寿命长、自放电率低、无记忆效应等优点，不过目前的成本难以降低，而且由于锂离子过于活泼，存在安全隐患，充电性能在低温下大打折扣。同时成品车的成本也比较大。其它的问题有如黄鲁成、顾威建在电动汽车单于的未来里而提到电动汽车面临的问题有：A.整车系统集成进程缓慢；B.充电机车的普及迟缓；C.市场认识不足；D.成本过高；E.政府缺乏有力的指引支持。康凤林、李军民在电动汽车发展分析里而提到电动汽车而临的问题有：A续驶里程有限；B.蓄电池使用寿命太短；c.蓄电池尺寸和质量制约；D.电动汽车价格昂贵；E.间接污染严重。在发展电动汽车是解决中国汽车能源的理想途径之一里面提到电动汽车面临的问题有：A.政府的政策支持；B.蓄电池技术；C.基础设施建设；D.电机等重要部件技术；E.电能的供应；F.市场的认可。3我国电动汽车产业未来发展：建立电动汽车技术创新平台目前我国电动汽车项目尚处于开发研制阶段，还没有形成生产规模，而对新一轮汽车产业结构调整及技术升级的局而，我们的技术力量分散，难形成合力，无法实现新一代汽车的突破性创新。因此，要实现跨越式发展，只有建立汽车技术创新平台，集成现有的汽车科技资源，以实现联合攻关，并形成良好的运作机制与相关科技创新平台实现互动，才能实现我国电动汽车产业的持续发展“发达国家的电动汽车已经取得了突破性的进展，正处于大规模产业化的边缘，将引起一场规模庞大的汽车技术革命，这将对我国电动汽车企业造成极大的威胁。我国汽车企业的规模及市场规模还不足以支撑新一代电动汽车产品开发所需的技术基础和成本支出，应在技术创新平台上促成“点”、“线”的集成，以寻求“面”的突破。因此，只有在政府的组织和重点支持下建立汽车技术创新平台，聚集科技人才和科技成果，才能实现新一代电子汽车关謎技术和重点的突破。主要参考文献1王望予.汽车设计M.北京:机械工业出版社2004.82于志生.汽车理论M.北京:机械工业出版社2006.83陈家瑞.汽车构造M.北京:机械工业出版社2005.14陈清泉，詹宜巨.21世纪的绿色交通工具电动车（第一版）M.北京：清华大学出版社.2000.10121035北京博信诚达信息咨询中心研发部2009-2012年中国电动汽车行业深度研究报告电子版J.SD20095016 Mehrdad Ehsani, Yimin Gao, Ali Emadi. Modern electric hybrid electric and cell vehiclesMCRC Press, 20097王刚，周荣电动汽车充电技术研究J.农业装备与车辆工程，2008,（6）8徐性怡电动汽车用电机控制器的设计方法与实践J，2009,（6）9姬芬竹，高峰电动汽车传动系参数设计及动力性仿真J北京航空航天大学学报，200610赵云电动汽车结构布置及设设.汽车电器，200611邹立群世界电动汽车发展综述J.电机与电器.2003.812刘磊.电动汽车蓄电池的建模与仿真研究.武汉理上大学硕士论文D.2005：131513李兴虎.电动汽车概论M.北京理工大学出版社，2005.814Chan C C. Chau KT. Modem electric vehicle technology. New York ： Oxford University Press. 200115WU Hongzing, Cheng, Shu-Kang, Cui Shu-Mei. Communication of Vehicle Management Unit in The Electric Vehicle J.IEEE Transactions on Magnetics 2005,41(1):514 51716刘清虎，郭孔辉动力参数的选择对纯电动汽车性能的影响J湖南大学学报（自然科学版）2003，30(3):6264 毕 业 设 计（论 文）文 献 综 述指导教师意见 指导教师： 年 月 日专业教研室审查意见 负责人： 年 月 日 56 AUTOMATIC TRANSMISSIONThe modern automatic transmission is by far , the most complicated mechanical component in todays automobile . It is a type of transmission that sifts itself . A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine . There are two basic types of automatic transmission based on whether the vehicle is rear wheel drive or front wheel drive . On a rear wheel drive car , the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position . A drive shaft connects the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels . Power flow on this system is simple and straight forward going from the engine , through the torque converter , then trough the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear transmission . On a front wheel drive car , the transmission is usually combined with the final drive to form what is called a transaxle . The engine on a front wheel drive car is usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car . Front axles are connected directly to the transaxle and provide power to front wheels . In this example , power floes from the engine , through the torque converter to a larger chain that sends the power through a 180 degree turn to the transmission that is along side the engine . From there , the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles .There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular . A much less popular rear and is connected by a drive shaft to the torque converter which is still mounted on the engine . This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling . Another rear drive system mounts everything , the engine , transmission and final drive in the rear . This rear engine arrangement is popular on the Porsche. Automobile available more than a century, especially from the mass production of motor vehicles and the automotive industry since the development of large, Car has been the economic development of the world for mankind to enter the modern life and have had a tremendous impact on the immeasurable, The progress of human society has made indelible contributions to the great, epoch-making set off arevolution. From From the vehicle as a power plant using internal combustion engine to start, auto transmission has become an important component. Is Generation is widely used in automotive reciprocating piston internal combustion engine with a small size, light weight, reliable operation and the use of The advantages of convenience, but its torque and speed range of smaller changes, and complex condition requires the use of motor vehicles Traction and the speed can be considerable changes in the scope. Therefore, its performance and vehicle dynamics and economy of There are large inter-contradictions, which contradictions of modern automotive internal combustion engine by itself is insoluble. Because Here, in the automotive power train set up the transmission and main reducer in order to achieve the purpose of deceleration by moment. Speed The main function of performance: change gear ratio of motor vehicles, and expand the wheel drive torque and rotational speed of the Fan Wai, in order to adapt to constantly changing driving cycle, while the engine in the most favorable conditions within the scope of work; no change in the direction of engine rotation, under the premise of the realization of cars driving back; the realization of the free, temporary Interruption of power transmission, in order to be able to start the engine, idling, etc. Variable-speed drive transmission by the manipulation of institutions and agencies. Change the transmission ratio by way of transmission is divided into There are class-type, non-stage and multi-purpose three. Have class most widely used transmission. It uses gear drive, with a number of transmission ratio setting. Stepless transmission Continuously Variable Transmission (CVT) transmission ratio of a certain The framework of multi-level changes may be unlimited, there is a common type of power and torque (dynamic fluid-type) and so on. Continuously Variable Transmission Transmission development is the ultimate goal, because only it can make the most economical engine in working condition Can provide the best vehicle fuel economy and optimal power in order to provide the most comfortable By the feeling. Todays CVT is a typical representative of the CVT and IVT, however as a result of the reliability of Poor, non-durable materials and high cost issues, development is not very good. Comprehensive refers to transmission torque converter and the mechanical components have the level of transmission variable hydraulic mechanical Speed, the transmission ratio can be between the maximum and minimum range of a few discontinuous change for no class, but its Significantly lower transmission efficiency than the efficiency of gear drives. 2 By manipulation, transmission control type can be divided into mandatory, automatic and semi-automatic control to manipulate three - Species . Mandatory on the driver to manipulate the direct transmission gear shift control for the majority of motor vehicles used Also known as Manual Transmission Manual Transmission (MT). Automatic transmission control selection of the transmission ratio (transmission) is carried out automatically. Just add the driver to manipulate Speed pedal, you can control the speed, also known as Automatic Transmission Automatic Transmission (AT). It is According to the speed and load (throttle pedal travel) for two-parameter control, stall in accordance with the above two Parameters to automatically take-off and landing. AT and MT in common is that they are level transmission, but AT According to the speed of the speed shift automatically, you can eliminate the manual transmission setback of the shift feel. However, AT also have many drawbacks, such as body complex, mechanical efficiency is not high, high cost, reliability and control Sensitivity remains to be increasing . AMT (Automated Mechanical Transmission) is in the traditional dry clutch and manual transmission gear based on the transformation of form, mainly to change the part of the manual gearshift control. That is, the overall structure of the MT cases the same switch to electronically controlled automatic transmission to achieve. Semi-automatic control, there are two forms of transmission. A number of stalls is a common automatic control, and the remaining stalls manipulated by the driver; the other is pre-style, that is, pre-selected pilot stalls, the clutch pedal in the down or release the accelerator pedal, the for retirement or an electromagnetic device to shift the hydraulic device. In recent years, with advances in vehicle technology and road traffic density increased, the performance requirements of the transmission is also getting higher and higher. A large number of automotive engineers in improving the performance of automobile transmission study a great deal of effort devoted to the rapid transmission of technology development, such as AT, AMT, DCT, CVT and the emergence of IVT. The modern automatic transmission consists of many components and systems that designed to work together in a symphony of planetary gear sets , the hydraulic system, seals and gaskets , the torque converter , the governor and the modulator or throttle cable and computer controls that has evolved over the years into what many mechanical inclined individuals consider to be an art from . Here try to used simple , generic explanation where possible to describe these systems .1）Planetary gear sets Automatic transmission contain many gears in various combinations . In a manual transmission , gears slide along shafts as you move the shift lever from one position to another , engaging various sizes gears as required in order to provide the correct gear ratio . In an automatic transmission , how ever , the gears are never physically moved and are always engaged to the same gears . This is accomplished through the use of planetary gear sets . The basic planetary gear set consists of a sun gear , a ring and two or more planet gears , all remaining in constant mesh . The planet gears are connected to each other through a common carrier which allows the gears to spin on shafts called “pinions” which are attached to the carrier . One example of a way that this system can be used is by connecting the ring gear to the input shaft coming from the engine , connecting the planet carrier to the output shaft , and locking the sun gear so that it cant move . In this scenario , when we turn the ring gear , the planets will “walk” along the sun gear ( which is held stationary ) causing the planet carrier to turn the output shaft in the same direction as the input shaft but at a slower speed causing gear reduction ( similar to a car in first gear ) . If we unlock the sun gear and lock any two elements together , this will cause all three elements to turn at the same speed so that to output shaft will turn at the same rate of speed as the input shaft . This is like a car that is third or high gear . Another way we can use a planetary gear set is by locking the planet carrier from moving , then applying power to the ring gear which will cause the sun gear to turn in opposite direction giving us reverse gear . The illustration in Figure shows how the simple system described above would look in an actual transmission . The input shaft is connected to the ring gear , the output shaft is connected to the planet carrier which is also connected to a “Multi-disk” clutch pack . The sun gear is connected to drum which is also connected to the other half of the clutch pack . Surrounding the outside of the drum is a band that can be tightened around the drum when required to prevent the drum with the attached sun gear from turning . The clutch pack is used , in this instance , to lock the planet carrier with the sun gear forcing both to turn at the same speed . If both the clutch pack and the band were released , the system would be in neutral . Turning the input shaft would turn the planet gears against the sun gear , but since noting is holding the sun gear , it will just spin free and have no effect on the output shaft . To place the unit in first gear , the band is applied to hold the sun gear from moving . To shift from first to high gear , the band is released and the clutch is applied causing the output shaft to turn at the same speed as the input shaft . Many more combinations are possible using two or more planetary sets connected in various way to provide the different forward speeds and reverse that are found in modern automatic transmission . 2）Clutch packA clutch pack consists of alternating disks that fit inside a clutch drum . Half of the disks are steel and have splines that fit into groves on the inside of the drum . The other half have a friction material bonded to their surface and have splines on the inside edge that fit groves on the outer surface of the adjoining hub . There is a piston inside the drum that is activated by oil pressure at the appropriate time to squeeze the clutch pack together so that the two components become locked and turn as one . 3）One-way Clutch A one-way clutch ( also known as a “sprag” clutch ) is a device that will allow a component such as ring gear to turn freely in one direction but not in the other . This effect is just like that bicycle , where the pedals will turn the wheel when pedaling forward , but will spin free when pedaling backward . A common place where a one-way clutch is used is in first gear when the shifter is in the drive position . When you begin to accelerate from a stop , the transmission starts out in first gear . But have you ever noticed what happens if you release the gas while it is still in first gear ? The vehicle continues to coast as if you were in neutral . Now , shift into Low gear instead of Drive . When you let go of the gas in this case , you will feel the engine slow you down just like a standard shift car . The reason for this is that in Drive , one-way clutch is used whereas in Low , a clutch pack or a band is used . 4）Torque Converter On automatic transmission , the torque converter takes the place of the clutch found on standard shift vehicles . It is there to allow the engine to continue running when the vehicle comes to a stop . The principle behind a torque converter is like taking a fan that is plugged into the wall and blowing air into another fan which is unplugged . If you grab the blade on the unplugged fan , you are able to hold it from turning but as soon as you let go , it will begin to speed up until it comes close to speed of the powered fan . The difference with a torque converter is that instead of using air it used oil or transmission fluid , to be more precise . A torque converter is a lager doughnut shaped device that is mounted between the engine and the transmission . It consists of three internal elements that work together to transmit power to the transmission . The three elements of the torque converter are the pump , the Turbine , and the Stator . The pump is mounted directly to the torque housing which in turn is bolted directly to the engines crankshaft and turns at engine speed . The turbine is inside the housing and is connected directly to the input shaft of the transmission providing power to move the vehicle . The stator is mounted to a one-way clutch so that it can spin freely in one direction but not in the other . Each of the three elements has fins mounted in them to precisely direct the flow of oil through the converter . With the engine running , transmission fluid is pulled into the pump section and is pushed outward by centrifugal force until it reaches the turbine section which stars it running . The fluid continues in a circular motion back towards the center of the turbine where it enters the stator . If the turbine is moving considerably slower than the pump , the fluid will make contact with the front of the stator fins which push the stator into the one way clutch and prevent it from turning . With the stator stopped , the fluid is directed by the stator fins to re-enter the pump at a “help” angle providing a torque increase . As the speed of the turbine catches up with the pump , the fluid starts hitting the stator blades on the back-side causing the stator to turn in the same direction as the pump and turbine . As the speed increase , all three elements begin to turn at approximately the same speed . Sine the 80s , in order to improve fuel economy , torque converters have been equipped with a lockup clutch which locks the turbine to the pump as the vehicle reaches approximately 40-50 mph . This lockup is controlled by computer and usually wont engage unless the transmission is in 3rd or 4th gear . 5）Hydraulic System The hydraulic system is a complex maze of passage and tubes that sends that sends transmission fluid and under pressure to all parts of the transmission and torque converter and . Transmission fluid serves a number of purpose including : shift control ,general lubrication and transmission cooling . Unlike the engine ,which uses oil primary for lubrication ,every aspect of a transmission s function is dependant on a constant supply of fluid is send pressure . In order to keep the transmission at normal operating temperature , a portion of the fluid is send to through one of two steel tubes to a special chamber that is submerged in anti-freeze in the radiator . Fluid passing through this chamber is cooled and then returned to the transmission through the other steel tube . A typical transmission has an avenge of ten quarts of fluid between the transmission , torque converter , and cooler tank , In fact , most of the components of a transmission are constantly submerged in fluid including the clutch packs and bands . The friction surfaces on these parts are designed to operate properly only when they are submerged in oil .6）Oil Pump The transmission oil pump ( not to confused with the pump element inside the torque converter ) is responsible for producing all the oil pressure that is required in the transmission . The oil pump is mounted to front of the transmission case and is directly connected to a flange on the engine crankshaft , the pump will produce pressure whenever the engine is running as there is a sufficient amount of transmission fluid available . The oil enters the pump through a filter that is located at bottom of the transmission oil pan and travels up a pickup tube directly to the oil pump . The oil is then sent , under pressure to the pressure regulator , the valve body and the rest of the components , as required . 7）Valve Body The valve body is the control center of the automatic transmission . It contains a maze of channels and passages that direct hydraulic fluid to the numerous valves which when activate the appropriate clutch pack of band servo to smoothly shift to the appropriate gear for each driving situation . Each of the many valves in the valve body has a specific purpose and is named for that function . For example the 2-3 shift valve activates the 2nd gear up-shift or the 3-2 shift timing valve which determines when a downshift should occur . The most important valve and the one that you have direct control over is the manual valve. The manual valve is directly connected to the gear shift handle and covers and uncovers various passages depending on what position the gear shift is paced in . When you place the gear shift in Drive , for instance , the manual valve directs fluid to the clutch pack ( s ) that activates 1st gear . It also sets up to monitor vehicle speed and throttle position so that it can determine the optimal time and the force for the 1-2 shift . On computer controlled transmission , you will also have electrical solenoids that are mounted in the valve body to direct fluid to the appropriate clutch packs or bands under computer control to more precisely control shift points .8）Seals and Gaskets An automatic transmission has many seals and gaskets to control the flow of hydraulic fluid and to keep it from leaking out . There are two main external seals : the front seal and the rear seal . The front seal seals the point where the torque converter mounts to the transmission case . This seal allows fluid to freely move from the converter to the transmission but keeps the fluid from leaking out . The rear seal keeps fluid from leaking past the output shaft . A seal is usually made of rubber ( similar to the rubber in a windshield wiper blade ) and is used to keep oil from leaking past a moving part such as a spinning shaft . In some cases , the rubber is assisted by a spring that holds he rubber in close contact with the spinning shaft . A gasket is a type of seal used to seal two stationary parts that are fasted together . Some common gasket materials are : paper , cork , rubber , silicone and soft metal . Aside from the main seals , there are also a number of other seals and gasket that vary from transmission to transmission . A common example is the rubber O-ring that seals the shaft for the shift control lever . This is the shaft that you move when you manipulate the gear shifter . Another example that is common to most transmission is the oil pan gasket . In fact , seals are required anywhere that a device needs to pass through the transmission case with each one being a potential source for leaks .9）Computer Controls The computer uses sensors on the engine and transmission to detect such things as throttle position , vehicle speed , engine speed , engine load , stop light switch position , etc . to control exact shift points as well as how soft or firm the shift should be . Some computerized transmission even learn your driving style and constantly adapt to it so that every shift is timed precisely when you would need it . Because of computer controls , sports models are coming out with the ability to take manual control of the transmission as through it were a stick shift lever through a special gate , then tapping it in one direction or the other in order to up-shift at will . The computer monitors this activity to make sure that the driver dose not select a gear that could over speed the engine and damage it . Another advantage to these “ smart” transmission is that they have a self diagnostic mode which can detect a problem early on and warn you with an indicator light on the dash . A technician can then plug test equipment in and retrieve a list of trouble codes that will help pinpoint where the problem is .自动变速器对于现代的汽车，自动变速器是一个复杂的组件，这种传递动力的方式，是液力变矩期充当离合器来连接发动机和变速器。 两个基本类型的自动变速器基于该车辆是否是前驱动或后驱动。对发动机前置后驱动的汽车，变速器通常安装在发动机后底盘中心与油门配合。变速器输出轴连接到后桥，把发动机的动力传递到后轮，动力传输系统是直线的，从发动机，通过液力变矩器、变速器、传动轴、最后直接到到达车轮。 对于发动机前置前轮驱动的汽车，变速器通常和差速器装在一起。对于前驱动的汽车，变速器安装在发动机一侧，前车轴直接连接到差速器上，把动力传递给前轮。在这个布置中，动力来自于发动机，通过液力变矩器、变速器输出的动力通过了一个180度大转弯，经过变速器沿发动机侧边通过传动轴输出到前轮。 还有其它的一些布置，发动机前置前驱动，发动机横向布置，装设一个分动器可以实现四轮驱动。但这种形式目前是最常用的：发动机中置后驱动，可以使重量均匀的分布在前、后轮之间，改善了操作性能；发动机后置后驱动，发动机、变速器、驱动轮都在后方，这种后置式的发动机的安排，是最满意的。 汽车问世百余年来，特别是从汽车的大批量生产及汽车工业的大发展以来，汽车己为世界经济的发展、为人类进入现代生活，产生了无法估量的巨大影响，为人类社会的进步作出了不可磨灭的巨大贡献，掀起了一场划时代的革命。自从汽车采用内燃机作为动力装置开始，变速器就成为汽车重要的组成部分。现代汽车上广泛采用的往复活塞式内燃机具有体积小、质量轻、工作可靠和使用方便等优点，但其转矩和转速变化范围较小，而复杂的使用条件则要求汽车的牵引力和车速能在相当大的范围内变化。故其性能与汽车的动力性和经济性之间存在着较大的矛盾，这对矛盾靠现代汽车的内燃机本身是无法解决的。因此，在汽车传动系中设置了变速器和主减速器，以达到减速增矩的目的。变速器的主要功能表现为：改变汽车的传动比，扩大驱动车轮转矩和转速的范围，以适应经常变化的行驶工况，同时使发动机在最有利的工况范围内工作；在发动机旋转方向不变的前提下，实现汽车的倒退行驶；实现空档，暂时中断动力传递，以便发动机能够起动、怠速等。变速器由变速传动机构和操纵机构组成。按传动比变化方式，变速器分为有级式、无级式和综合式三种。有级式变速器应用最为广泛。它采用齿轮传动，具有若干个定值传动比。无级式变速器Continuously Variable Transmission(CVT)的传动比在一定的范围内可按无限多级变化，常见的有电力式和液力式(动液式)等。无级变速器是变速器发展的终极目标，因为只有它才能使发动机处于最经济的工作状况，才能为整车提供最优的燃油经济性和最优的动力性，才能给人们提供最舒适的乘坐感觉。当今无级变速器的典型代表就是CVT和IVT，然而由于工作可靠性差、材料不耐用和成本高等问题，发展不是很好。综合式变速器是指由液力变矩器和机械式有级变速器组成的液力机械式变速器，其传动比可在最大值和最小值之间的几个间断范围内作无级变化，但其传动效率明显低于比齿轮传动效率。2按操纵方式，变速器又可分为强制操纵式、自动操纵式和半自动操纵式三种。强制操纵式变速器靠驾驶员直接操纵变速杆换档，为大多数汽车所采用，也称手动变速器Manual Transmission（MT）。自动操纵式变速器的传动比选择(换档)是自动进行的。驾驶员只需操纵加速踏板，即可控制车速，也称自动变速器Automatic Transmission（AT）。它是根据车速和负荷（油门踏板的行程）来进行双参数控制，档位根据上面的两个参数来自动升降。AT与MT的共同点，就是二者都是有级式变速器，只不过AT能根据车速的快慢来自动实现换档，可以消除手动变速器“顿挫”的换档感觉。但是，AT也有很多缺点