摘要本设计的任务是设计一台10款捷达两轴手动变速器。与中间轴式变速器比较，两轴式变速器有结构简单、轮廓尺寸小、布置方便、中间档位传动效率高和噪声低等优点。根据轿车的外形、轮距、轴距、最小离地间隙、最小转弯半径、车辆重量、满载重量以及最高车速等参数结合自己选择的适合于该轿车的发动机型号可以得出发动机的最大功率、最大扭矩、排量等重要的参数。再结合某些轿车的基本参数，选择适当的主减速比。根据上述参数，再结合汽车设计、汽车理论、机械设计等相关知识，计算出相关的变速器参数并论证设计的合理性。它功用是：①改变传动比，扩大驱动轮转矩和转速的变化范围，以适应经常变化的行驶条件，如起步、加速、上坡等，同时使发动机在有利的工况下工作；②在发动机旋转方向不变的前提下，使汽车能倒退行驶；③利用空档，中断动力传递，以使发动机能够起动、怠速，并便于发动机换档或进行动力输出。这台变速器具有五个前进档（包括一个超速档五档）和一个倒档，并通过锁环式同步器来实现换档。关键词：变速器，锁环式同步器，传动比，中间轴，第二轴，齿轮ABSTRACTThedutyofthisdesignistodesignaFRtypemanualtransmissionusedinthesaloon,It’sthecountershaft-typetransmissiongearbox.Thistransmissionhastwoprominentmerits:Firstly,thetransmissionefficiencyofthedirectdrivekeepsoffhigh,theattritionandthenoisearealsoslightest;Secondly,it’sallowedtoobtaininthebigergearratioofthefirstgearwhenthecenterdistanceissmaller.Accordingtothecontour,track，wheelbase，thesmallestgroundclearance,thesmallestturningradium,thevehiclesweight,theall-upweightaswellasthehighestspeedandsoon,unionthechoosingenginemodelwecanobtaintheimportantparametersofthemaxpower,themaxtorque,thedisplacementandsoon.Accordingtothebasicparametersofthecertainsaloon,choosethesuitablefinaldriveratio.Accordingtotheaboveparameters,combiningtheknowledgeofautomobiledesign,automobiletheory,machinedesignandsoon,calculatethecorrelatedparametersofthegearboxandprooftherationalityofthedesign.Itsfunctionis:①Changinggearratio,expandingthetorqueofthedrivingwheelandtherangeoftherotationalspeed,toadaptthetravelconditionwhichfrequentlychanges,likestart,acceleration,climbingandsoon,simultaneouslycausestheenginetoworkundertheadvantageousoperatingmode;②Underthepremiseoftheinvariablerotation,enablestheautomobiletotravelback;③Usingneutral,severancesthepowertransmission,tomaketheenginestart,idle,andisadvantageousfortheenginetoshiftgearsortocarryonthedynamicoutput.Thisgearboxhasfive(includingoverdrive—fifthgear)andareversegear,andthroughtheinertialtypeofsynchronizertorealizeshiftgears.KeywordS：transmission,inertialtypeofs