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汽车齿轮齿条式转向系设计【齿轮齿条式转向器】,汽车,齿轮,齿条,转向,设计,转向器

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西安工业大学北方信息工程学院毕业设计（论文）中期报告题目：汽车齿轮齿条式转向系设计系 别 机电信息系 专 业 机械设计制造及其自动化 班 级 B070203 姓 名 路宽 学 号 B07020338 导 师 姚慧 2011年 3 月 15 日撰写内容要求（可加页）： 一、 设计（论文）进展状况1. 经过了前期的准备工作和开题答辩以来，对本毕业设计课题的深入了解和学习，查阅了汽车转向系的相关资料，对齿轮齿条式转向器的类型划分及特征结构进行了仔细的分析，通过老师的指导，对本课题需要完成的工作有了明确的目标并且完成了外文翻译。2 完成了如下的结构设计计算和装配图的绘制 转向轮侧偏角的计算 原地转向力矩MR的计算 转向器的角传动比的计算 转向盘手力FH的计算 转向盘扭矩TZ 转向横拉杆直径计算 主动齿轮轴的计算 齿面接触疲劳强度校核 齿根弯曲疲劳强度计算校核二 存在问题及解决措施1. 齿轮齿条式转向器的结构设计不合理，齿轮齿条啮合间隙较大，影响传动的平稳性和降低传动效率。2. 转向系中没有设计防伤安全机构方案分析与计算。在后期需要设计一个自动消除齿轮齿条间间隙的装置和弹性联轴器防伤机构，更加完善整个转向系的设计。三 后期工作安排1经老师发现问题后，仔细改正其中装配草图的不足和不合理的地方。 2撰写说明书，完成毕业设计的其余部分。 3仔细完成毕业设计论文和准备最后的论文答辩。 指导教师签字： 年 月 日注：1. 正文：宋体小四号字，行距22磅；标题：加粗 宋体四号字2. 中期报告由各系集中归档保存，不装订入册。毕业设计（论文）任务书系别 机电信息系 专业 机械设计制造及其自动化班级1230203姓名 XXXX 学号123020338 1.毕业设计（论文）题目： 汽车齿轮齿条式转向系设计 2.题目背景和意义：目前，汽车工业发展迅猛，转向系统作为汽车的关键部件的也得到了相应的发展，已形成专业化、系列化生产的格局。转向器的性能好坏对于汽车在高速行驶过程中所需的操纵轻便、稳定性好及安全行驶有很大影响。为适应汽车工业的发展形势，熟悉汽车部件的设计，本课题设计一汽车齿轮齿条式转向器。 3.设计(论文)的主要内容（理工科含技术指标）：（1）了解齿轮齿条式转向系的基本结构、发展现状； （2）完成齿轮齿条式转向系统的结构设计，主要零部件的设计计算与强度校核； （3）绘制所设计的齿轮齿条式转向系统的装配图； 4.设计的基本要求及进度安排（含起始时间、设计地点）： （1）13周：调研并收集资料，完成开题报告；（2）35周：阅读资料，分析齿轮齿条式转向系的工作原理和基本结构；（3）610周：完成齿轮齿条式转向系统的结构设计计算；（4）1115周：完成齿轮齿条式转向系统结构装配图；（5）1618周完成论文撰写，准备答辩。 5.毕业设计（论文）的工作量要求 毕业设计论文一篇，不少于10000字； 实验（时数）*或实习（天数）： 2周 图纸（幅面和张数）*： 齿轮齿条式转向系的结构装配图，A0图纸（折合）2张 其他要求： 外文翻译不少于1000字，参考文献不少于15篇。 指导教师签名： 年 月 日 学生签名： 年 月 日 系主任审批： 年 月 日说明：1本表一式二份，一份由各系集中归档保存，一份学生留存。2 带*项可根据学科特点选填。西安工业大学北方信息工程学院毕业设计(论文)开题报告题目： 汽车齿轮齿条式转向系设计系 别 机电信息系 专 业 机械设计制造及其自动化 班 级 B070203 姓 名 路宽 学 号 B07020338 导 师 姚慧 2010年11月28日开题报告填写要求1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。此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。2开题报告内容必须按教务处统一设计的电子文档标准格式（可从教务处网页上下载）填写并打印（禁止打印在其它纸上后剪贴），完成后应及时交给指导教师审阅。3开题报告字数应在1500字以上，参考文献应不少于15篇（不包括辞典、手册，其中外文文献至少3篇），文中引用参考文献处应标出文献序号，“参考文献”应按附件中参考文献“注释格式”的要求书写。4 年、月、日的日期一律用阿拉伯数字书写，例：“ 2010年11月28日”。撰写内容要求（可加页，小四号宋体，行距22磅）： 1.毕业设计（论文）综述（题目背景、研究意义及国内外相关研究情况）本次毕业设计的题目是汽车齿轮齿条式转向系的设计，主要是以齿轮齿条式转向器的设计为中心。齿轮齿条式转向器最早出现在1902年，当时由于其本身结构不够完善，整车布置的限制以及道路条件差等因素，导致路面反冲激烈，噪音较大以及转向性能较差等缺陷，使此种转向器的应用受到很大的限制。然而近廿来，特别是最近几年，却有了很大发展，其发展速度超过循环球式转向器，国际舆论甚至认为：目前汽车工业正在抛弃有70年历史的摇臂型转向器。这种看法的主要依据是：（1）国外大部分主要汽车在制造厂大规模地推荐横置发动机、前轮驱动的小客车，这样对齿轮齿条式转向系的布置十分灵活方便，比摇臂式转向器的传动机构更为简化。（2）高速公路发展使车辆速度大大提高，为获得良好的路感，对转向器刚性的要求愈来愈高，而循环球式转向器在刚性上远远不如齿轮齿条式转向器。（3）齿轮齿条式转向器本身具备的优点如结构简单、成本低、高达80%以上的传动效率、具有多种输入输出形式便于布置、重量轻（转向器壳多数采用压铸铝合金、有的厂还在研制塑料壳体）、刚性好等等，能使高速车辆的驾驶者获得良好的路感。此外、由于齿轮齿条式转向器自身结构的发展，如采用新型的手动变速比和动力转向，其使用范围已从轿车、微型车及轻型汽车逐步发展到中型和重型汽车转向系。从目前情况看，国际上汽车工业发达国家生产的汽车转向器结合基本上可归为两大类：摇臂式转向器和齿轮齿条式转向器，前者主要型式有球面蜗杆滚轮式、循环球式和曲柄指销式三种，其中循环球式较为主要，在美国和日本的汽车中使用较多。而西欧国家，尤其是法国的汽车中则以齿轮齿条式转向器为主。日本NSK公司的统计资料表明了世界上各种转向器的采用比率及变化趋势，1968年到1975年循环球式转向器比率在40%46%之间变化，而齿轮齿条式转向器的比率则由31%增加到43%，发展较快。此外，日本和美国循环球式转向器的产量占90%以上，而西欧国家齿轮齿条式转向器则占较大的百分比，西德为57%，英国为77%，法国为96%。从目前国外著名转向器厂制造的齿轮齿条式转向器主要应用于轿车，微型和轻型汽车方面，加美国TRW公司的齿轮齿条式转向器用于前轴负载7001250公斤的车辆，西德ZF厂的同类产品用于前轴负载荷为9002400公斤的车辆，但该厂新设计的7856型齿轮齿条式动力转向器可用于前轴负载荷达6500公斤的汽车。从产量看，ZF厂1980年生产了30万套，占机械转向器的一半。英国伯曼厂日产1200套，为其生产的各种转向器之首。日本汽车转向器虽然以循环球式为主，但近年随着微型汽车的迅速发展，也开始大量采用齿轮齿条式转向器。如大发、三菱微型汽车等。齿轮齿条式转向器长期以来是我国汽车转向器生产中的一项空白，直到最近几年由于大量进口汽车组装件，技术引进以及与国外合资企业的发展，才开始研制开发和生产这种转向器。其中主要有与西德大众汽车公司合资生产的桑塔纳中级轿车，日本大发公司的微型汽车以及意大利菲亚特公司的依维柯轻型客货车系列等。仅从以上三种车型的最终生产纲领统计就达40余万辆，再加上其它进口车型的修配任务，估计齿轮齿条式转向器产量将达50余万套，可以估计到90年代时这种转向器将占我国汽车转向器产量的40%50%。因此，国内转向器行业对此都十分重视。如上海汽车底盘厂为了配套生产桑塔纳轿车和SH110微型汽车的齿轮齿条式转向器，已经大力进行工厂技术改造和技术设备的引进工作，要在90年代达到以齿轮齿条式转向器为主的各种转向器产量共50万套的年生产纲领。 2.本课题研究的主要内容和拟采用的研究方案、研究方法或措施本课题研究的是汽车齿轮齿条式转向系，主要是以齿轮齿条式转向器的设计为中心。齿轮齿条式转向器由与转向轴做成一体的转向齿轮和常与转向横拉杆做成一体的齿条组成。齿轮齿条式转向器在汽车上的布置形式与转向梯形和转向器传动输出形式有关，图1所示为最常见的布置形式。（a）转向器固定于车架或车身两侧输出的非独立悬挂布置；（b）转向器固定于车架或车身中央输出的非独立悬挂布置；（c）为转向器固定于车身前围单侧输出的独立悬挂布置（如奥迪80和桑塔纳轿车）；（d）转向器固定于车架单侧输出的独立悬挂布置（如日本三菱、大发微型汽车）。齿轮齿条式转向器的传动输出形式主要有如下四种形式。（a）中间输入，两端输出；（b）侧面输入，两端输出；（c）侧面输入，中间输出；（d）侧面输入，一端输出通过对齿轮齿条式转向器的初步了解，现在可以采用的方案确定为以下几种：方案一：采用侧面输入，两端输出方案时，如图（2）由于转向拉杆长度受到限制，容易与悬梁系统导向机构产生运动干涉。采用斜齿圆柱齿轮与斜齿齿条啮合的齿轮齿条式转向器，重合度增加，运转平稳，冲击与工作噪声均下降，而且齿轮轴线与齿条轴线之间的夹角易于满足总体设计要求。齿条断面形状为V形，与圆形断面比较，消耗的材料少，约节省20%，故质量小，位于齿条下面的两斜面与齿条托座接触，可用来防止齿条绕轴线转动。图2为两端输出的齿轮齿条式转向器，作为传动副主动件的转向齿轮轴11通过轴承12和13安装在转向壳体5中，其上端通过花键与万向节叉10和转向轴连接。与转向齿轮啮合的转向齿条4水平布置，两端通过球头座3与转向横拉杆1相连。弹簧7通过压块9将齿条压靠在齿轮上，保证无间隙啮合。弹簧的预紧力可用调整螺塞6调整。当转动转向盘时，转向器齿轮轴11转动，使转向车轮偏转，从而使汽车转向。 图21转向横拉杆 2防尘套 3球头座4转向齿条5转向器壳体6调整螺塞7压紧弹簧8锁紧螺母9压块10万向节11转向齿轮轴12向心球轴承13滚针轴承方案二：采用侧面输入，中间输出方案时，如图（3）与齿条固定连接的左、右拉杆延伸到接近汽车纵向对称平面附近。优点：由于拉杆长度增加，车轮上、下跳动时拉杆摆角减小，有利于减少车轮上、下跳动时转向系与悬架系的运动干涉。缺点：为了将左、右横拉杆固定在齿条上，并且两拉杆与齿条会同时向左、右移动一定的距离，必须在转向器壳体上开有轴向方向的长槽，使齿条有一部分裸露出来，然后用螺栓将横拉杆固定在齿条上。转向器壳体上的长槽使其强度受到削弱，为了不使外界脏东西落入转向器内，又必须用密封罩将它们密封。齿轮齿条转向器采用直齿圆柱齿轮与直齿齿条啮合，则运转平稳性降低，冲击力大，工作噪声增加。此外，齿轮轴线与齿条轴线之间的夹角只能是直角，为此与总体布置不适应而遭淘汰。齿条断面形状为圆形，齿条制作工艺比较简单。中间输出的齿轮齿条式转向器如图3所示，其结果及工作原理与两端输出的齿轮齿条式转向器基本相同，不同之处在于它在转向齿条的中部用螺栓6与左右转向横拉杆7相连。 图31 万向节叉2转向齿轮轴3调整螺母4向心球轴承5滚针轴承6固定螺栓7转向横拉杆8转向器壳体9防尘套10转向齿条11调整螺塞12锁紧螺母13压紧弹簧14压块 通过以上比较，选用第一种方案，齿轮齿条式转向器的传动副为齿轮和齿条，其结构简单，布置方便，制造容易，故仅广泛用于微型汽车和轿车上，但转向传动比较小，齿条沿其长度方向磨损不均匀，且通常布置在前轮轴线之后，转向传动副的主动件斜圆柱小齿轮，它和装在外壳中的从动件齿条相啮合，外壳固定在车身上。齿条利用两个球接头直接和两根分开的左、右横拉杆相连。由于汽车的车型不同，所使用的齿轮齿条式转向器的参数也有所不同。在这里本次设计选择长安奔奔2010款1.0AMT的车型。其具体性能参数如下表： 表2长安奔奔2010款1.0AMT参数性能参数配置最大功率51.2/5600kw/rpm最大扭矩90/4600Nm/rpm最高时速158km/h 在整个设计过程中，齿轮齿条式转向器的零件的建模、及其仿真均在三维软件中完成，目前比较常用的有Pro/ESolid Works和UG。在这三者中，Pro/E的造型功能相比其他两个要大一些，而且在软件优化方面做得比较好，所以此次设计中的以上工作均在Pro/E中完成。二维装配图在AutoCAD中完成。3.本课题研究的重点及难点，前期已开展工作本课题的以齿轮齿条转向器的设计为中心，研究的重点一是汽车总体构架参数对汽车转向的影响；二是机械转向器的选择、三是齿轮和齿条的合理匹配，以满足转向器的正确传动比和强度要求；四是动力转向机构设计；五是梯形结构设计。而研究的难点是进行了齿轮齿条式转向器的设计，和对转向齿轮轴的校核的设计，和对转向齿轮轴的计算及校核，以及结构设计和装配的绘制，完成三维建模并进行模型装配。 因此本课题在考虑上述要求和因素的基础上研究利用转向盘的旋转带动传动机构的齿轮齿条转向轴转向，通过万向节带动转向齿轮轴旋转，转向齿轮轴与转向齿条啮合，从而促使转向齿条直线运动，实现转向器结构简单紧凑，轴向尺寸短且零件数目少的优点又能增加助力，从而实现汽车转向的稳定性和灵敏性。因此设计的主要方法和理论采用汽车设计的经验参数和大学所学机械设计的课程内容进行设计。在前期要阅读大量的文件，要把转向器方面的基本知识要十分的了解，并且要有一定的阅读量，是自己的知识得到很大的扩充。在这个基础上要经常练习画图软件，争取在需要的时候能够很快的画出图形。前期要做好文献的阅读，查阅资料，了解转向系的各个结构的工作原理等前期准备。4.完成本课题的工作方案及进度计划（按周次填写） 第1周-第3周：前期准备，查阅资料，了解课题，准备开题答辩； 第4周-第6周： 分析齿轮齿条式转向系的结构和工作原理； 第7周-第11周：确定设计方案，进行结构设计计算； 第12周-第14周：完成结构设计和装配的绘制； 第15周-第17周：完善装配模型，撰写毕业论文； 第18周：毕业答辩 5 指导教师意见（对课题的深度、广度及工作量的意见） 指导教师： 年 月 日6 所在系审查意见： 系主管领导： 年 月 日参考文献 1 陈益良齿轮齿条式转向器简介J汽车与配件1986年06期2 党胡申转向器引进项目简介J汽车与配件1988年02期3 毕大宁略论我国汽车转向器生产发展之路J汽车与配件1995年19期4 余席桂，侯玉英，钟诗清汽车转向器啮合间隙测试方法J武汉汽车工业大学学报1997年04期5 刘冰齿轮齿条转向器的建模及分析J上海工程技术大学学报2006年01期6 谢刚，殷国富，周丹晨汽车转向器变传动比齿轮齿形的三维动态仿真设计J机床与液压2003年04期 7 陈勇，朱敬德，徐解民汽车转向器油缸和壳体的压铆装置设计J机械制造与自动化2006年05期 8 杨丙辉，郭钢，郭卫光，等汽车转向器零件参数化特征设计系统的研制J机械制造与自动化2008年03期 9 雷良育，施晓芳，张青汽车转向器综合性能测试控制台J自动化与仪表2001年03期10 张枫念关于汽车转向器摇臂轴齿扇齿根弯曲强度计算的研究和探讨J轻型汽车技术2000念03期 11 贾巨民，张蕾，唐天元，等汽车变速比齿轮齿条式转向器啮合原理（I）J机械技术1998年01期12 贾巨民，张蕾， 唐天元汽车变速比齿轮齿条式转向器啮合原理（II）J机械科学与技术1998年02期13 邓飞，欧家福，颜尧，等齿轮齿条式动力转向器试验方法及标准研究J交通标准化2009年Z2期14 张敏中齿轮齿条式转向器转向梯形机构优化设计J江苏工学院学报1994年02期15 牟向东，唐新蓬，陶建民汽车转向器变速比特性对操轻便性的影响1999年12期Design and implementation of a novelhybrid-electric-motorcycle transmissionKuen-Bao Sheu*, Tsung-Hua HsuInstitute of Mechanical and Electro-Mechanical Engineering, National Formosa University,64 Wunhua Road, Huwei, Yuenlin 63208, Taiwan, ROCReceived 30 July 2005; received in revised form 2 October 2005; accepted 8 October 2005Available online 19 December 2005AbstractThis hybrid power system incorporates a mechanical type rubber V-belt, continuously-variabletransmission (CVT) and chain drives to combine power of the two power sources, a gasoline engineand an electric motor. The system uses four different modes in order to maximize the performanceand reduce emissions: electric-motor mode; engine mode; engine/charging mode; and power mode.The main advantages of this new transmission include the use of only one electric motor/generatorand the shift of the operating mode accomplished by the mechanical-type clutches for easy controland low cost. Kinematic analyses and design are achieved to obtain the size of each component ofthis system. A design example is fabricated and tested.? 2005 Elsevier Ltd. All rights reserved.Keywords: Hybrid electric motorcycle; Transmission; CVT1. IntroductionMotorcycles/scooters are a popular mode of transportation in many urban areas ofAsia, such as Taiwan because of limited space, short daily trip distance, population densityand the easy operation and maintenance of motorcycles. However, the exhausts from gas-oline motorcycles cause serious environmental pollution in Taiwan?s cities. The Environ-mental Protection Administration of the ROC has implemented some policies to reduce0306-2619/$ - see front matter ? 2005 Elsevier Ltd. All rights reserved.doi:10.1016/j.apenergy.2005.10.004*Corresponding author. Tel.: +886 05 6315697; fax: +886 05 6321571.E-mail address: kbsheu.tw (K.-B. Sheu).Applied Energy 83 (2006) 959974/locate/apenergyAPPLIEDENERGYair pollution, such as the strict exhaust standards for gasoline vehicles, an electric motor-cycle development action plan, and a subsidy for purchasing electric scooters 1. To facil-itate this, the government and industry have been applying fuel-cell technology to powerscooters 25. However, the goal of replacing polluting combustion-engine motorcycleswith battery powered ones has not been successful in Taiwan 6. Existing and proposedbattery/fuel cell powered motorcycle designs have low performance and are not likelyto displace the gasoline motorcycle in the near future 7,8. Another approach to reduceboth pollution and get better performance is to utilize a hybrid concept of internal-com-bustion engine and battery at this stage. Over the past few years, hybrid electric vehicles(HEVs), primarily automobiles, have been actively developed and marketed 914. Thisstudy considers the design of a hybrid power-transmitting system that is suitable formotorcycles. In 1997, Honda Motors released a hybrid two-wheeler concept in the Tokyomotor show with the key goals of a 60% reduction in CO2emission and 2.5 times betterfuel-efficiency. In this system, a water-cooled 49 cc gasoline engine is packed with a DCbrushless electric-motor together driving the rear wheel. The gasoline engine deliverspower for high-speed performance and for hill climbing while the electric motor engagesfor low-speed cruising. In 1999, AVL Company proposed a hybrid system that used a50 cc carburetted lean-burn two-stroke engine with a 0.75 kW electric motor mountedon the engine crankshaft mainly to provide increased torque during acceleration 15.Matsuto and Wachigai also proposed a motorcycle hybrid-drive system 1618. The maincomponents of this system consists of the two power sources of an engine and an electricmotor, a traction drive continuously-variable transmission (CVT), a final reduction driveand three clutches. The transmission shaft and the electric motor shaft are coaxial in seriesin the longitudinal direction of the vehicular body and in parallel with the crank shaft ofthe engine.Traditionally, the transmission devices used for motorcycles are divided into two cate-gories: (1) stepped transmission devices, that work by alternating the gear drives, and (2)CVTs, that transmit power by using a rubber V-shaped belt. Advantages of the rubberV-belt CVTs include smoother-speed characteristics, adequate speed ratio, a simpler mech-anism, low cost, less maintenance, etc. However, the mechanical efficiency of the mechan-ical-type rubber V-belt CVT is quite low, especially, at the instant of speed ratio changewith frequent stops 19,20.This paper presents a novel hybrid electric motorcycle transmission whose primary fea-ture is a mechanical type rubber V-belt CVT and chain drives to combine the power of twopower sources, a gasoline engine and an electric motor. The hybrid power system is to runthe electric motor at start-up and during low speeds, so that the emissions in urban areasare limited. As the vehicle speed increases to and passes a medium speed, the engine poweris transmitted to the rubber V-belt CVT driving the vehicle. This combination can avoidthe low-efficiency regions of the CVT and retain good handling.This paper begins with a description of the hybrid-electric transmission and proceedswith a kinematic analysis and design to obtain the size of each component of this system.Finally, the prototype of this new design is fabricated and tested.2. Parallel hybrid transmissionTraditionally, HEVs for the automotive industries were classified into two types, serieshybrid and parallel hybrid. With the recent developments of HEVs, they can now be cat-960K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974egorized in four kinds: series hybrid, parallel hybrid, seriesparallel hybrid, and complexhybrid 21. A series HEV uses the engine driving force after converting it into electricityvia a generator. In a parallel hybrid, two power sources such as an engine and an electricmotor are used to drive the vehicle simultaneously. The seriesparallel HEV is a combina-tion of both the series and parallel hybrid systems. In addition, a complex hybrid systeminvolves a complex configuration which cannot be categorized into the above three types.As shown in Fig. 1, the proposed motorcycle hybrid system, a parallel hybrid, consists of agasoline engine, an electric motor, a transmission, a power inverter, and an electronic con-troller. The transmission connects the engine, the electric motor, and the rear wheel of themotorcycle 22. The transmission is made up of a mechanical type rubber V-belt CVTwith a shoe-type centrifugal clutch (engine clutch), two chain drives with two one-wayclutches, and a final drive consisting of two gear-pairs. The electric motor can functionas an electric motor or a generator, according to the driving condition and battery powerlevels. The electronic controller receives commands from the driver and feedback signalsfrom sensors to select the operating mode and to decide how much power is needed todrive the wheels and how much to charge the battery.The proposed hybrid power system can operate in four different modes to maximize theperformance and reduce emissions: (1) electric motor mode; (2) engine modes 1 and 2; (3)engine/charging mode; and (4) power mode.(1) Electric motor modeAs in start-up or low-speed situation, the electric motor converts chemical energy storedin the battery to drive the motorcycle while the gasoline engine is shut down to reduceemissions. As shown in Fig. 1, the electric motor transmits power via the chain drive 2and the final drive alone powers the motorcycle by engaging the one-way clutch 2, whereasthe one-way clutch 1 and engine clutch are disengaged.(2) Engine mode 1 and mode 2During moderate and high speeds, the engine clutch is disengaged and both the one-way clutches 1 and 2 are engaged to operate the engine mode 1. Here, the engine alonedrives the motorcycle via the chain drive 1 and 2 and through the final drive. As the enginespeed increased, the engine clutch engaged and the one-way clutch 2 is automaticallyV-belt CVT Chaindrive 2 Final drive One-wayclutch 1 Motorcycle Engine clutch BatteryController InverterOperatorcommandsFeed-back signalsEngine Motor/Generator Chaindrive 1 One-wayclutch 2 Fig. 1. Schematic diagram of the hybrid-electric motorcycle transmission.K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974961disengaged. Here, the engine alone drives the motorcycle through the rubber V-belt CVTand the final drive to operate the engine mode 2. If a higher speed of the shift point fromthe electric motor mode to the engine mode is selected, the engine mode 1 can be automat-ically discontinued. In addition, since the engine and the electric motor output shaft arecoupled with chain drive 1, the electric motor can be switched into a neutral mode to allowthe electric motor output shaft to spin freely.(3) Engine/charging modeDuring moderate or high-speed cruising, both the engine clutch and one-way clutch 1are engaged and the one-way clutch 2 is disengaged. Part of the engine power is transmit-ted to the motorcycle through the rubber V-belt CVT and the final drive, and the otherpart to the electric motor via the chain drive 1 and one-way clutch 1. If the battery poweris low, the electric motor is switched into the generator mode for charging the battery.Since the engine can be operating under high-load conditions, by reducing the low-loaddriving time in this operating mode, the hybrid system has less fuel consumption.(4) Power modeWhen climbing hills, the motorcycle is operated in a power mode. Here, the electricmotor power via the one-way clutch 2 and the engine power through the rubber V-beltCVT are coupled together to drive the motorcycle simultaneously.3. Kinematic analysis and design3.1. Speed ratio of the chain drive and final driveThe speed ratio is defined as the ratio of the output to the input link speeds. The trans-mission mechanism here uses two chain drives and a final drive assembly. The chain driveconsists of an input and output sprocket connected with a silent chain. The speed ratio ofthe chain drive isrc xcn=xcr Zcr=Zcn;1where xcr(xcn) and Zcr(Zcn) denote the angular speed and the number of teeth on the input(output) sprocket of the chain drive, respectively. The final drive assembly consists of twogear pairs. The speed ratio of the final drive isrf Zf1? Zf3=Zf2? Zf4;2where Zf1, Zf2, Zf3, and Zf4are the numbers of teeth on the four gears of the final drive,respectively.3.2. Speed ratio of the CVTThe mechanical-type CVT used here operates by a speed-sensing pulley as the driverand a torque-sensing pulley as the driver jointed by a rubber V-belt. The driver consistsof a movable flange, a fixed flange, and several centrifugal rollers (see Fig. 3(a) and thedriven components consist of a movable flange, a fixed flange, a torsioncompressionspring, and a torque-sensing mechanism (see Fig. 2). There is an axial force and torqueacting on the driver and driven pulleys, respectively. The force balance between boththe force acting on the driver and driven pulleys determines the actual speed-ratio ofthe CVT in a running situation. There have been numerous analyses of the mechanical-962K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974type CVTs 2328. Here, we utilize the results of Sheu et al. 28 with some modification toanalyze the CVT of the hybrid-electric motorcycle transmission.The axial force acting on the movable flange of the driver and driven pulley depends onthe engine speed and the external load of the motorcycle, respectively. The external loadFroadresults from rolling force, wind force, the inclination force and acceleration force asFroad lrW cosh CnV2 W sinh W DW a=g;3where V = Rwxwrepresents the vehicle speed, in which Rwis the driver wheel radius andxwoutput speed; W is the total weight of the vehicle and people; DW is the equivalentvehicle weight; lris the rolling friction coefficient; Cnis the equivalent drag-coefficient;a is the instantaneous acceleration of the vehicle; h is the angle of slope, and g is the gravityacceleration.Letting gfbe the mechanical efficiency of the final drive, the torque acting on the drivenpulley of the CVT can be written asTvnFroadRwrfgf4and the belt tension difference (F1? F2) can be expressed asF1? F2 TvnRn;5where Rnis the pitch diameter of the driven pulley.Referring to Fig. 2, the driven pulley has a movable flange that can slide axially alongthe shaft. Vehicle load on the driven shaft is converted to an axial force on the belt in thegroove by the helical cam. Based on the force equilibrium acting on the movable flange bythe torsioncompression spring Fsand the force Fhc, due to the vehicle load acting on thehelical cam, the axial force of the driven pulley Fvn, operating at an impending openingcondition of a pitch diameter Dnand belt tension difference, can be expressed asFvn Fhc? FsDnDa?F1? F22?cosb ? lasinbsinb lacosb Fp KnDn0? Dntana=2;6Fig. 2. Drive pulley of the rubber V-belt CVT.K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974963where b is the angle between the helical cam surface of the torque-sensing mechanism andthe shaft centerline; Dais the diameter of the helical cam; Dn0is the minimum pith diam-eter of the driven pulley; Fpis the compression preload of the torsioncompression spring;Knis the spring rate of the torsioncompression spring; a is the groove angle of the pulley;and lais the coefficient of friction on the helical cam.For the axial force of the driver pulley, as seen in Fig. 3(b), based on the force equilib-rium, the axial force of the movable flange of the driver pulley acted on by the centrifugalroller can be derived asFclmymx2ecosclhsincsinc?lhcosc?sindlbsindcosd?lbsind?;7where lband lhdenote the coefficients of friction between the roller and the roller backcontact plate and the roller housing, respectively; m is the total mass of the centrifugal roll-er; d is the angle between the roller back contact plate and the perpendicular to shaft cen-terline; c is the contact angle of the housing and the centrifugal roller; and xeis the inputangular velocity of the driver pulley. The distance between the center of the roller and theFig. 3. Drive pulley of the rubber V-belt CVT. (a) Layout of the CVT drive pulley. (b) Control parameters of theCVT drive pulley.964K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974shaft centerline ymcan be expressed as ym= ym0? Smcosd, where ym0is the location ofthe roller at zero rpm.The housing and centrifugal roller contact angle c is related to the location of the cen-trifugal roller, as expressed bycosc Rm? yoff? Smcosdq ? Rm;8where q is the radius of curvature of the roller housing, Rmis the radius of the centrifugalroller, yoffis the distance between the center point of the roller housing and the shaft sur-face, and Smis the travel of the roller along the roller center point. In addition, the axialdisplacement of the movable flange Srcan be expressed asSrffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiq ? Rm2? Rm yoff2q?ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiq ? Rm2? Rm yoff Smcosd2q Smsind Dr? Drmintana2;9where Dris the pitch diameter of the driver pulley and a is the groove angle of the pulley.Substituting Eq. (9) into Eq. (8), the housing and centrifugal roller contact angle can beobtained.When the driver and driven pulley are combined in a drive, the axial force applied to thebelt by the driven pulley is transmitted to the driver pulley. The equations that relate thebelt tension and axial force of the driver pulley Fvrand the driven pulley Fvnare 23FvrF1hr21 ? ltana=2l tana=2?;10Fvn F1? F2cosa=2 ? lsin/sina=22lcos/?;11F1F2 explhncon/lsin/cosa=2 sina=2?;12where hris the belt wrap angle on the driver pulley, hnis the belt wrap angle on the drivenpulley,F1andF2arethebelttensionofthetightsideandslackside,listhecoefficientoffric-tionbetweenthebeltandpulley,/isthefrictionangle,andaisthegrooveangleofthepulley.From Eqs. (5) and (6), the axial force of the driven pulley Fvnand the belt tension dif-ference (F1? F2) are given, and substituting Eqs. (11) and (12), the belt tension of the tightside and slack side can be determined asF1F1? F21 ? 1=F1=F2;13F2 F1? F1? F2.14For a given F1, the axial force Fvrof the driver pulley provided by the belt can be deter-mined from Eq. (10). When the axial force Fvrof the driver pulley provided by the belt andthe axial force Fclof the driver pulley supplied by the centrifugal roller are balanced, thedrive is operated at a steady-state condition. The speed ratio rcvtof the CVT can bedetermined from the ratio of the diameters of the driver pulley Drand driven pulley Dn.A computer program for analyzing and designing the mechanical-type CVT can bedeveloped based on the design procedure described above. Fig. 4 shows the operatingcharacteristics between simulations with the presented model and measurements carriedout with an existing 125 cc gasoline-engine scooter. The solid lines and symbols representK.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974965the analytical and experimental results, respectively, as the driving forces under the run-ning conditions of a steady speed on a flat-level road. The coefficients of friction of theCVT used in the simulation program are 25: la= 0.2, l = 0.45, and lb(lh) = 0.05: theparameters of the driving forces are lr= 0.01, W = 170 kg, h = 0?, a = 0, andCn= 0.37. This existing transmission is tested on a test stand, as shown in Section 4.The analytical and experimental results for the operating characteristics of the existing125 cc gasoline scooter are generally in good agreement. Therefore, this model can be usedto develop the computer program for analyzing and designing the mechanical-type CVT ofthe hybrid-electric motorcycle transmission.3.3. The speed ratio of the hybrid-power system(1) Electric-motor modeIn this, the one-way clutch 2 engaged, whereas the one-way clutch 1 and engine clutchare disengaged. The electric motor power via the chain drive 2 and the final drive alonedrives the motorcycle. Letting rc2and rfbe the speed ratio of the chain drive 2 and finaldrive, the speed ratio of this mode isrM rc2? rf.15(2) Engine mode 1 and mode 2In the engine mode 1, the engine clutch is disengaged and both the one-way clutches 1and 2 are engaged. The engine alone drives the motorcycle via the chain drives 1 and 2 andthrough the final drive. The speed ratio of the engine mode 1 can be written asrE1 rc1? rc2? rf;16where rc1denotes the speed ratio of the chain drive 1. In the engine mode 2, the engineclutch is engaged and the one-way clutch 2 is automatically disengaged. The engine alonedrives the motorcycle through the V-belt CVT and the final drive. Letting rcvtbe the speedratio of the CVT, the speed ratio of the engine mode 2 isrE2 rcvt? rf.170 1020 30 40 5060 70 80 90 1009000800070006000500040003000200010000MeasuredSimulationA 125cc gas-engine scooter running on flat level road(rcvt)max(rcvt)minEngine speed (rpm) Vehicle speed (km/hr) Fig. 4. Operating characteristics of a 125 cc gasoline-engine scooter.966K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974(3) Engine/charging modeIn the engine/charging mode, part of the engine power is transmitted to the motorcyclethrough the rubber V-belt CVT and the final drive is the same as in engine mode 2, and theother part to the electric generator via the chain drive 1 and one-way clutch 1. The outputspeed xgof the electric generator can be written asxg xE? rc1.18(4) Power modeIn the power mode, the one-way clutch 2 and engine clutch are engaged, whereas theone-way clutch 1 is disengaged. The electric motor and the engine together drive themotorcycle. However, the one-way clutch allows a relative motion in one direction andblocks it in the other direction. Due to this constraint, the speed of the engine xEand elec-tric motor xMare related for this mode as xM rc2P xE rcvt. The output speed xWofthe power mode can be expressed asxW xM? rc2? rf xE? rcvt? rf.194. Design examplesThe design items for the hybrid-electric motorcycle transmission include the speed ratioof the chain drives and final drive, the maximum speed ratio of the CVT, and the param-eters of the control unit of the CVT. An existing 125 cc gasoline-engine scooter that hasthe following performance and requirements is used as the design target for this new trans-mission: (1) maximum engine speed is 85009000 rpm and top speed of motorcycle is90 km/h, (2) start-up acceleration capability is about 0.20.3 g, (3) minimum and maxi-mum speed ratio of the CVT are 0, 38 and 1.14, respectively, (4) the speed ratio of the finaldrive is 0.128, and (5) the rear wheel?s radius is 0.215 m.4.1. Prototype developmentThe minimum speed ratio of a transmission system affects the start-up acceleration. Inthe electric motor mode of the hybrid power system, for the given output torque of theelectric motor TMand the total efficiency gMin this mode, the traction force Frearofthe motorcycle can be calculated asFrearTMgMrMRw.20Substituting Eq. (20) into Eq. (3), we obtain the start-up acceleration of the motorcycle asasTMwgMrMRw? lrW cosh CnV2 W sinh? g=W DW ;21where TMwdenotes the electric-motor?s torque for the full open-throttle. The speed ratioof the electric motor mode can be achieved by setting the vehicle speed V = 0 and the angleslope h = 0. Hence, considering the electric-motor?s power and the start-up accelerationcapability of the existing scooter, the number of teeth on the sprockets of the chain drive2 and the gears of the final drive are adopted here as Zcr2= 22 and Zcn2= 43, andK.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974967Zf1= 15, Zf2= 42, Zf3= 14 and Zf4= 39. Therefore, the speed ratio of the chain drive 2and the final drive of the prototype are rc2= 0.5116 and rf= 0.1282, respectively. Thespeed ratio of the electric-motor mode is rM= rc2 rf= 0.06559 and the motorcycle out-put speed in the power mode is xW= 0.06559 xM.Since the engine and the electric motor output shaft are always coupled with the chaindrive 1, the main factors considered in the design of chain drive 1 are the relationship ofthe rated speed of the electric motor and the shift point from the electric motor mode intothe engine mode. In this example, let the number of teeth on the sprockets of the chaindrive 1 be Zcr1= 22 and Zcn1= 33. Then, the speed ratio of the chain drive 1 isrc1= 0.6667. The speed ratio of the engine mode 1 is rE1= rc1 rc2 rf= 0.0437 andthe output speed of the electric generator is xg= 0.6667 xE.The top speed this motorcycle here occurs for the engine mode 2. For the given outputtorque of the gasoline engine TEand the total efficiency gE2in this mode, the traction forceFrearof the motorcycle isFrearTEgE2rE2Rw.22Substituting Eq. (22) into Eq. (3) and setting h = 0?, TE= TEwand a = 0, the top speedVmaxof the hybrid-electric motorcycle can be determined asVmaxffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi1CnTEwgE2rcvtmaxrfRw? lrW?s;23where TEwis the maximum output torque of the engine. The maximum speed-ratio(rcvt)maxof the CVT can be obtained from Eq. (23). Considering the shift point fromthe electric motor mode into the engine mode, the minimum speed ratio (rcvt)minof theCVT can be estimated. In this example, (rcvt)min= 0.45 and (rcvt)max= 1.14 is adopted.Hence, the speed ratio of the engine mode 2 is rE2= 0.057690.14615. In addition, theminimum and maximum speed ratio of the CVT can be expressed asrcvtmaxDrmaxDnmin;rcvtminDrminDnmax.24Therefore, the minimum and maximum diameter of the driver pulley and driven pulley, as(Dr)max= 80.5 mm, (Dr)min= 52.5 mm and (Dn)max= 105 mm, (Dn)min= 70 mm, can besatisfied.In order to improve the match between engine and transmission, it is necessary to opti-mize the control parameters of the CVT. The program is developed on the basis of thedesign procedure described in Section 3.2. The target function here is selected so thatthe variablespeed-ratio range of the CVT is engine speeds 40007000 rpm. Table 1 liststhe control parameters of the CVT of the prototype.4.2. Test and experimental resultsAs shown in Fig. 5(a), an experimental rig was constructed to test the prototype hybrid-electricmotorcycle transmission consistingoftwopower sources,anexternalloadandasso-968K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974ciated instruments. A detailed arrangement of the test rig is illustrated by the schematic dia-gram Fig. 5(b). The two power sources of the test rig, a 125 cc gasoline-engine and a DCelectric motor (0.8 kW, maximum speed 6000 rpm), are adopted from existing scooters.Themotorcycleisconsideredasaninertiaandtheotherdrivingforceissimulatedbyabrake(MITSUBISHI ZKB-20XN, 200 N-m). The instruments of the test rig include three torquetransducers (KYOWA, 10 N-m, 20 N-m and 200 N-m) and three optical encoders for mea-suring the input and output torques and angular displacements of the transmission, respec-tively.Eachtorquetransducerwasconnectedtotheshaftthoughaflexiblecoupling inordertoavoidanybendingmomentsthatwouldaffectthemeasurement.Thedatafromthetorquetransducers were sent via a dynamic strain amplifier (KYOWA DPM-712B-M33) and theTable 1Control parameters of the CVT of the prototypeTorque ramp angle (b)45?Preload of torsioncompression spring (Fp)35 kgSpring rate of torsioncompression spring (Kn)228 kg/mGroove angle of the pulley (a)30?Radius of curvature of roller housing (q)0.029 mMass of centrifugal roller (m)0.078 kgRadius of centrifugal roller (Rm)0.009 mAngle of roller back contacted plane (d)32?460Location of roller at zero rpm (ymo)0.028 mFig. 5. Diagram of the test rig. (a) Photograph of the test rig. (b) Schematic diagram of the test rig.K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974969signalsfromtheencodersweresentviaanacquisitioncard(NIPCI-6070-E,1 MHz)andPCfor data acquisition and storage.A PC-based control system with a Matlab/Simulink environment is developed toachieve the prototype test. Fig. 6 shows the time chart of the test for the shift from elec-tric-motor mode into engine mode under the running conditions upon a flat level road:lr= 0.01, W = 200 kg, h = 0?, a = 0, and Cn= 0.388. This figure shows the input speedof electric motor and gasoline engine, gear-ratio operated during the electric and enginemodes, as well as the velocity of motorcycle. This test runs followed a desired ramp veloc-ity profile from 0 to 50 km/h and then maintains a constant speed. As the motorcyclebegins to accelerate, the engine has not started. The motorcycle operates in electric motormode (shown in the shaded areas of the figure) until its speed reaches about 20 km/h (7 s),at which point it shifts to engine mode.Fig. 7 shows the test results of the power mode under a constant load equal to 2 kg m.This test has three desired step velocity profiles, 515 km/h, 1520 km/h, and 2025 km/h,respectively. The shaded areas in the figure indicate where the transmission is operated inthe power mode and the others areas are the engine mode. The shaded areas in the figurereveal that the input torque is shared between the gasoline engine and the electric motor.Fig. 8 shows the operating characteristics of the hybrid-electric motorcycle transmissionunder the running conditions on a flat level road. Data are taken every 5 km/h of themotorcycle speed and recorded as the speed becomes constant. There are two operationmodes shown in Fig. 8. In the region for speeds less than 15 km/h, the transmission oper-ates in the electric-motor mode and the other region operates in the engine mode. Fig. 9Fig. 6. Test results, electric-motor mode and engine mode, 0% grade.970K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974shows the total mechanical efficiency of the prototype under the running conditions on aflat level road and on a 2.5% grade road, respectively. Efficiency data are calculateddirectly from experimental results, that is, g = Toutxout/Tinxin. The mechanical efficiencyFig. 7. Test results, power mode, 0% grade.ElectricmotormodeEnginemode 20204060801001030507090Vehicle speed v(km/hr)0200040006000800010003000500070009000Input speed (rpm)(rE2)max(rE2)minrMMeasuredSimulationFig. 8. Operating characteristics of the prototype.K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974971of this transmission is about 0.6 and 0.7 for the electric-motor mode on a flat level roadand on a 2.5% grade road, respectively. For the engine mode, these figures show thatthe total efficiencies are about 0.40.7 and 0.50.7 on a flat level road and on a 2.5% graderoad, respectively.5. ConclusionsThis paper presents a novel hybrid-electric motorcycle transmission system that can beused for regulating the power flow of a parallel hybrid-electric motorcycle. To maximizethe performance and reduce emissions, this transmission can operate in four differentmodes: electric-motor mode; engine mode; engine/charging mode; and power mode. Inthe electric-motor mode, the electric motor alone drives the motorcycle at start-up andfor low speeds. In the power mode, the electric motor and the engine drive the motorcyclesimultaneously to achieve maximum power. In the engine/charging mode, the electric-motor functions as a generator to charge the batteries, and it is possible to run the engineat an optimal operating condition by regulating the speed and load of the generator at thesame time. In the engine mode, the engine alone drives the motorcycle using the rubberV-belt CVT to retain good handling.Advantages of the hybrid-power system proposed here include (1) using only one elec-tric motor/generator and the shift of the operating mode are accomplished by the mechan-ical-type clutches for the easy control and low cost, (2) utilizing a continuously-variabletransmission system and of electric motor/generator to control the operational rangeand torque output of the engine to improve the total energy efficiency, (3) taking advan-tage of the desired characteristics of high torque, high efficiency, and zero emission of theelectric motor at low speeds by using it instead of the conventional engine for drivingpower at start-up and low speeds.In this article, the proposed hybrid-power system is explained first and kinematic anal-yses are performed for the overall transmission mechanism. In addition, an analysis modelof the mechanical-type CVT is developed and verified by measurem