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1/37352履带拖拉机（中央传动及转向离合器设计）摘要中央传动用来增加传动系的传动比,以达到减速增扭的目的,通常还用来改变转矩的传递方向,使转矩从纵置的变速箱输出轴传递给横置的中央传动两侧输出轴。中央传动应有适当的传动比,以保证拖拉机具有良好的牵引性与经济性;结构应紧凑,以减小后桥尺寸和和质量,保证后桥有足够的离地间隙；齿轮装置应有足够的承载能力和支承刚度,如系锥齿轮副,则还应便于调整。中央传动的齿轮形式目前主要有圆柱齿轮和圆锥齿轮。圆柱齿轮结构简单,加工较容易,在传动时不致产生轴向力。但仅适用于采用横置变速箱的拖拉机。而圆锥齿轮应用则较为广泛。履带拖拉机在行使过程中，需要经常改变行驶方向，这就需要有一套能够按照司机意志来改变或恢复拖拉机行驶方向的专设机构，它将司机踩下转向离合器踏板的动作转变为车轮的偏转动作，这就是所谓的转向系统。转向性能是保证车辆安全，减轻驾驶员劳动强度和提高作业效率的重要因素。转向离合器转向系统由于构造简单，制造方便，维修容易，在拖拉机上广泛采用。它具有转向半径小，直线行驶性好等优点。但由于传递的转矩较大，只得采用多片式离合器，而多片式离合器分离彻底性比较差。这对转向离合器来说，除了使摩擦面的磨损略微增大外，对整机性能没有太大影响，不像主离合器分离不彻底会造成换档困难。关键词：中央传动，转向离合器，锥齿轮，转向系统2/37352TRACKEDTRACTOR（CENTRALTRANSMISSIONANDSTEERINGCLUTCHDESIGN）ABSTRACTCentralspreadtousetoincreasetospreadtomovetofastenofspreadandmoveratio,thepurposethattoattaintodeceleratetoincreasetotwist,usuallyreturntousetochangethetorquetodeliverthedirection,maketorqueplacebecomesoontheboxoutputsthestalktodelivertohorizontalplacecentraltospreadtomovethetwosidesexportationstalk.Centralspreadtomoveandshouldhaveappropriateofspreadandmoveratio,withtheassurancethatthetractorhastoleadthesexandeconomygoodly;structureshouldtightlypacked,aftertoletupthebridgesizeandandquantity,theassuranceisbehindthebridgehastoleaveagroundofcleftenough;Thewheelgeardeviceshouldhavetheenoughloadingabilityandpaytoacceptjustdegree,returnifdepartmentthebevelgearsisvice,shouldeasytoadjustment.Centralspreadthedynamicwheelgearformtomainlyhavethecylinderwheelgearandthebevelgearsescurrently.Thecylinderwheelgearstructureissimple,processingtocompareeasily,producethestalktowarddintunlikelywhilespreadmove.Butbeapplicabletotheadoptiononlyhorizontalplacetobecomesoonthetractorofthebox.Buttheconewheelgeartheapplicationthencompareextensively.Thetracktractorprofessionalmakesintheprocess,needingtousuallychangetodrivethedirection,thisneedtobehaveasetofcanchangeorrecoverthetractortodrivetheparticularlyestablishofthedirectionorganizationaccordingtothedriverwill,itdeflecttheactionchangethatthedrivertramplesbottomtochangedirectiontheclutchpedalforthefelloeaction,thisistochangedirectionthesystemsocalledly.Changedirectionthefunctionistoguaranteethevehiclesafety,easingthepilotthelaborstrengthandraiseimportantfactorofthehomeworkefficiency.steeringmechanismchangesdirectionthesystembecauseofstructureinbrief,makeconvenience,maintaineasily,inthedallianceonboardextensive3/37doption.Ithastheradiusofchangedirectionsmall,drivesexgoodetc.advantagestraightly.Butbecausethetorquethatdelivercomparegreatly,havetoseveraltypeclutchesofadoption,butseveraltypesclutchseparatethoroughlysexisworse.Thissaystowardssteeringmechanismcome,inadditiontomakingrubtofaceofwearingawaytheinchingaggrandizement,havingnotothewholemachinefunctiontoaffecttoogreatly,beunlikethemainclutchseparationillsuccessandwillresultinshiftgearthedifficulty.Keywords:Centraltransmission,steeringclutch,bevelgears,steeringsystem4/37目录第一章前言···································································1第二章中央传动及转向离合器概论·······································2§2.1履带拖拉机转向机构概述·········································2§2.2中央传动的概述····················································3第三章中央传动及转向离合器方案分析·································5§3.1转向离合器方案分析···············································5§3.2中央传动方案分析················································10第四章转向系统设计计算·················································14§4.1螺旋锥齿轮的计算················································14§4.2转向离合器设计计算··············································17§4.3带式制动器的设计计算···········································19第五章主要零件的强度校核与计算······································21§5.1螺旋锥齿轮的承载能力计算·····································21§5.2轴强度计算·························································22§5.3轴承寿命计算······················································24第六章结论··································································28参考文献········································································29致谢············································································305/37第一章前言拖拉机的主要任务是用来拖带农机具进行各种田间作业（如翻地、播种、中耕等）；也可作为其他农业机械（如脱谷机、扬场机等）的动力；另外拖带拖车可进行运输作业。为适应农业生产中各项作业的需要，拖拉机分有履带式和轮式两种。履带式拖拉机的特点是行走部分与地面的接触面积大，压强小，对土壤压实的作用小，而且不易打滑，可以在湿度较大的土壤上进行作业。一般履带式拖拉机的离地间隙小而功率大，适用于大面积的翻地、播种等主要农业作业。如东方红－54和75拖拉机。拖拉机基本上是由发动机、传动装置、车架和行走装置、操纵装置、工作装置和电气设备等六部分组成。传动装置的功用是将发动机的动力传递给行走装置或其他工作装置；在驾驶员的操纵下，使拖拉机起步；停车；改变牵引力或行进方向，它包括离合器、变速箱、中央传动和最终传动等。如下图所示。图1-1履带拖拉机传动系简图1－离合器2－联轴节3－变速箱4－中央传动5－转向离合器6－制动器7－最终传动8－动力输出轴本毕业设计说明书，主要讲述了最终传动的选择设计和方案分析。对最终传动的分类和工作原理进行了深入的对比和分析，选出最优方案来进行设计，选择合适的机构和零件。这次设计是在以往所学基础和专业课程的基础上设计的，经过对比其他车型同类装置的设计方案，有选择的借鉴或创新来进行设计。6/37第二章中央传动及转向离合器概论§2.1履带拖拉机转向机构概述履带拖拉机转向机构用来改变驱动力在两侧履带上的分配(包括改变方向),造成转向力矩以实现拖拉机转向。履带拖拉机转向机构可按不同特征分类:1、按转向时的速度分转向时平均速度不变,即对称面上的A点的速度和直线行使时速度相等(如图a所示),所有差速器式转向机构(单差速器、双差速器、差速器式双功率流转向机构)都属于这一类。快速侧履带的纵向对称面B点(如图b所示)的速度等于。转向离合器、单级和多级行星式(包括双功率流)转向机构属于这一类。快速侧、慢速侧履带对称面上的B、C点(如图c所示)的速度均低于,有些采用电传动的坦克即速车辆属于这一类。图2-1履带拖拉机转向时速度的改变1—外侧履带2―外侧履带2、按固定转向半径的大小和数目分固定转向半径,是指两侧履带各按指定的速度转向时形成的转向半径,这7/37里所谓的“指定的”是指可由人准确控制的、不包括驱动轮被切断动力后被机体推着前进的各种速度。（1）具有一个固定的转向半径R,R=0.5B(B为轨距),转向离合器、单级