本科生毕业设计（论文）PAGEIV摘要变速器是能固定或改变输出轴和输入轴传动比的齿轮传动装置,又称变速箱，是HYPERLINK"http://baike.baidu.com/view/4033.htm"\t"_blank"汽车传动系中最主要的部件之一。HYPERLINK"http://baike.baidu.com/view/22398.htm"\t"_blank"汽车变速器是通过改变传动比，改变HYPERLINK"http://baike.baidu.com/view/47475.htm"\t"_blank"发动机曲轴的输出转矩，适应在起步、加速、行驶以及克服各种道路阻碍等不同行驶条件下对驱动车轮牵引力及车速不同要求的需要，使发动机在最有利的工况内工作。设计要求达到换挡迅速、省力、方便、有较高的工作效率、工作噪声低。本次设计的是中型货车变速器。它的布置方案采用三轴式5+1挡和锁销式同步器换挡，并对倒挡齿轮和拨叉进行合理布置，其中一轴和第二轴的轴线在同一直线上。这种布置形式缩短了变速器轴向尺寸，在保证挡数不变的情况下，减少齿轮数目，从而使变速器结构更加紧凑。首先利用已知参数确定变速器各挡传动比、中心矩，然后确定齿轮的模数、压力角、齿宽等参数。由中心矩确定箱体的长度、高度和中间轴及二轴的轴径，然后对中间轴和各挡齿轮进行校核，最后绘制装配图及零件图。设计结论表明，变速器齿轮及各轴尺寸确定，各轴强度的校核满足设计要求，设计结构合理。关键词：变速器；齿轮；中间轴；同步器AbstractTransmissionisatransmissiondevicewhichcanfixorchangegearratioattheoutputshaftandthetransmissioninputshaft,alsoknownasthegearbox,transmissionisoneofthemostimportantcomponents.Bychangingthetransmissionratio,Automobiletransmissioncanchangethetorqueofenginecrankshaft,adapttothestart,acceleration,trafficandovercomeroadobstaclesofdifferentdrivingconditionsonthedrivewheels,tractionandthespeedrequirementsofthedifferentneeds,sothattheengineworkinthemostfavorableconditions.Thetransmissiondesignrequirethatshiftrapidly,saving,convenientandhigherefficiency,lownoisework.Thisdesignisamanualtransmissiongearboxofmediumtruck.Aschemeofstructurewiththreeshafts,five(5+1)shiftsandLockingpintypesynchronizerwasadoptedhere,combinetopourtoblockwheelgearandstirforktocarryonareasonabledecoration.Thefirstandsecondshaftswerearrangedinline.Thiskindofstructurereducesthegearboxdimensionintheaxisdirection,inassuranceblocktocountundertheconstantcircumstance,decreasewheelgearnumber.Thereforemakesthedesignedtransmissiongearboxmorecompact.Usingthegivenbasicparameters,itwasfirstlydeterminedthetransmissionratioofeachshift,theshaftcenterdistances,thegearmodulus,thegearpressinganglesandwidths,andsoon.Andthenthegeneraldimensionofthegearbox,includingitslength,widthandheight.Finally,someengineeringdrawingswerecarriedout.Thecalculated