汽车电动助力转向系统的设计论文.doc

哈尔滨工业大学华德应用技术学院毕业设计（论文）-I-目录摘要································································································IAbstract··························································································II第1章绪论·················································································11.1汽车转向系统简介···························································11.1.1转向系的设计要求···················································11.2EPS的特点及发展现状····················································21.2.1EPS与其他系统比较···············································21.2.2EPS的特点·····························································21.2.3EPS在国内外的应用状况·········································31.3本课题的研究意义···························································4第2章电动助力转向系统的总体组成·············································52.1电动助力转向系统的机理及类型·······································52.1.1电动助力转向系统的机理·········································52.1.2电动助力转向系统的类型·········································72.2电动助力转向系统的关键部件··········································92.2.1扭矩传感器····························································92.2.2车速传感器····························································92.2.3电动机································································92.2.4减速机构······························································102.2.5电子控制单元·······················································102.3电动助力转向的助力特性················································11第3章电动助力转向系统的设计··················································123.1对动力转向机构的要求··················································123.2齿轮齿条转向器的设计与计算········································123.2.1转向系计算载荷的确定··········································133.2.2齿轮齿条式转向器的设计·······································143.2.3齿轮齿条转向器转向横拉杆的运动分析···················223.2.4齿轮齿条传动受力分析··········································243.2.5齿轮轴的强度校核·················································24第4章转向传动机构的优化设计··················································294.1结构与布置···································································29哈尔滨工业大学华德应用技术学院毕业设计（论文）-I-4.2用解析法求内、外轮转角关系········································304.3转向传动机构的优化设计···············································324.3.1目标函数的建立····················································324.3.2设计变量与约束条件·············································334.4研究结论······································································36结论·····························································································37致谢·····························································································39参考文献······················································································40附录1··························································································41附录2··························································································46摘要汽车转向系统可按转向的能源不同分为机械转向系统和动力转向系统两类。汽车电动助力转向系统是一种新型的汽车动力转向系统，与传统液压转向系统相比，采用电动机直接提供助力，具有多方面优越性。近年来已有很多中高档汽车配备了动力转向系统装置，EPS研究也成为汽车工业的热门课题之一，具有重要研究价值和巨大潜在应用前景。在本文中重点进行齿轮齿条转向器的设计计算和对转向齿轮轴的校核，及转向传动机构的优化设计。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，并做了归纳和总结。关键词转向系统；电动助力转向系统；齿轮齿条转向器；优化设计哈尔滨工业大学华德应用技术学院毕业设计（论文）-I-AbstractThesteeringsystemcanbedividedintomechanicalenergyandpowersteeringsystem.Electricpowersteeringsystemisanewtypeofvehiclepowersteeringsystem,comparedwithtraditionalhydraulicsteeringsystems,directlywiththemotorpower,hasmanyadvantages.Inrecentyears,manyintheluxurycarhavebeenequippedwithapowersteeringsystemdevice,EPSstudieshavebecomeahottopicinautomotiveindustry,greatresearchvalueandgreatpotentialapplications.Thisarticlefocusonthedesignoftherackandpinionsteeringgearshaftcalculationandverification,andoptimizationofsteeringlinkage.Themainmethodsandtheoriesofexperiencewithautomotivedesignparametersandtheuniversitycurriculuminmechanicaldesigntodesign,andmadeandsummarized.KeywordsSteeringSystem；ElectricPowerSteering；Rackandpinionsteering；Optimization哈尔滨工业大学华德应用技术学院毕业设计（论文）-I-第1章绪论1.1汽车转向系统简介汽车转向系是用来保持或者改变汽车行驶方向的机构，在汽车转向行驶时，保证各转向轮之间有协调的转角关系。它由转向操纵机构、转向器和转向传动机构组成。转向系统作为汽车的一个重要组成部分，其性能的好坏将直接影响到汽车的转向特性、稳定性、和行驶安全性。目前汽车转向技术主要有七大类：手动转向技术（MS）、液压助力转向技术（HPS）、电控液压助力转向技术（ECHPS）、电动助力转向技术（EPS）、四轮转向技术（4WS）、主动前轮转向技术（AFS）和线控转向技术（SBW）。转向系统市场上以HPS、ECHPS、EPS应用为主。电动助力转向具有节约燃料、有利于环境、可变力转向、易实现产品模块化等优点，是一项紧扣当今汽车发展主题的新技术，他是目前国内转向技术的研究热点。1.1.1转向系的设计要求(1)汽车转弯行驶时，全部车轮应绕瞬时转向中心旋转，任何车轮不应有侧滑。不满足这项要求会加速轮胎磨损，并降低汽车的行驶稳定性。(2)汽车转型行驶后，在驾驶员松开转向盘的条件下，转向轮能自动返回到直线行驶位置，并稳定行驶。(3)汽车在任何行驶状态下，转向轮都不得产生共振，转向盘没有摆动。(4)转向传动机构和悬架导向装置共同工作时，由于运动不协调使车轮产生的摆动应最小。(5)保证汽车有较高的机动性，具有迅速和小转弯行驶能力。(6)操纵轻便。(7)转向轮碰撞到障碍物以后，传给转向盘的反冲力要尽可能小。(8)转向器和转向传动机构的球头处，有消除因磨损而产生间隙的调整机构。(9)在车祸中，当转向轴和转向盘由于车架或车身变形而共同后移时，转向系应有能使驾驶员免遭或减轻伤害的防伤装置。(10)进行运动校核，保证转向轮与转向盘转动方向一致。