UNIT 8 CLUTCHES,MANUAL TRANSMISSIONS AND DRIVE LINETEXT ADRIVE LINE PROFESSIONAL ENGLISHUNIT 7 CLUTCHES,MANUAL TRANSMISSIONS AND DRIVE LINETEXTA DRIVE LINE Drive Shaft Universal Joint Final Drive Differential本次课学习内容本次课学习目标l掌握传动系统的有关英文专业词汇l能够较好地用已知翻译技巧进行课文翻译l训练快速阅读能力，较高的阅读速度l能够较熟练地运用“倒译法”。NEW WORDSgraphitegrfaitn.石墨石墨torsionalt:nla.扭力的扭力的,扭转的扭转的trunniontrninn.耳轴耳轴tripodtraipdn.三脚架，三脚桌三脚架，三脚桌resemblerizemblv.象象,类似类似rampstubrmpstbn.斜坡斜坡,坡道，滑道，滑轨坡道，滑道，滑轨n.树桩，短轴树桩，短轴PHRASES AND EXPRESSIONSdrive shaft传动轴传动轴torsional damper扭转减振器扭转减振器flexible joint柔性接头柔性接头cross and roller universal joint十字轴式万向节十字轴式万向节cardan universal joint十字轴式万向节，万向节十字轴式万向节，万向节needle bearing滚针轴承滚针轴承snap ring卡环卡环CV joint等速万向节等速万向节exploded view分解图分解图ring gear齿圈齿圈PHRASES AND EXPRESSIONSdifferential pinion shaft差速器行星齿轮轴差速器行星齿轮轴ring gear pinion shaft主减速器主动锥齿轮轴主减速器主动锥齿轮轴side gear半轴齿轮半轴齿轮worm and wheel gear蜗杆蜗轮机构蜗杆蜗轮机构friction limited-slip differential摩擦式限滑差速器摩擦式限滑差速器worm gear蜗轮副蜗轮副spur gear正齿轮，直齿圆柱齿轮正齿轮，直齿圆柱齿轮Torsen differential托森差速器托森差速器DriveShaftTherear-wheeldriveshaftishollowtoreduceweight,buthasadiameterlargeenoughtogivetheshaftgreatstrength,Figure8-5.Steel,aluminum,andgraphiteareusedindriveshaftconstruction.Somehavearubber-mountedtorsionaldamper.Figure8-5Therear-wheeldrivepropellershaftDrive LineAyokeandsplinedstub(whereused)areweldedtotheendsofahollowshaft.Theshaftmustruntrueandbecarefullybalancedtoavoidvibrations1.Thedriveshaftisoftenturningathighspeedsandcancausegreatdamageifbent,imbalanced,orifthereiswearintheflexiblejoints.UniversalJointThecrossandrolleruniversaljoint,sometimescalledacardanuniversaljoint,consistsofacentercrossandtwoyokes,showninFigure8-6.Theyokesareattachedtothecrossthroughneedlebearingassemblies,usuallycalledbearingcaps.Thebearingcapsareretainedintheyokebysnaprings,U-bolts,orboltedplates.Thebearingcaprollerssurroundthecrossends.Thesecrossendsarecalledtrunnions.Thisallowstheyokestoswivelonthecrosswithaminimumamountoffriction.Drive LineFigure8-6SimpleuniversaljointConstantVelocity(CV)JointCVjointsperformthesamefunctionsastheuniversaljointonrear-wheeldrivevehicles.CVjointscandrivethevehicleandcompensateforsteeringactionswhileproducinglessvibrationthanauniversaljoint.Figure8-7illustratesoneparticularfront-wheeldriveCVjointandshaftassembly.Front-wheeldriveaxlesareequippedwithinboard(inside)andoutboard(outside)CVjoints.Figure8-7showsonesucharrangement.CVjointsareusedonthefrontaxlesofsomefour-wheeldrivevehiclesandrear-wheeldrivevehicleswithindependentrearsuspensions.Drive LineFigure8-7Anexplodedviewofafour-wheel-drivefrontaxleandconstantvelocityjointDrive LineDrive LineTherearetwobasicCVjointtypes:tripodandRzeppa(alsocalledballandchannel)type,Bothoftheseareconstantvelocitydesigns.TheRzeppajointisbyfarthemostcommon.TripodJointFigure8-8showsthetripodjoint.Itiscomposedofthreetrunnionsinsideofathreechannelhousing.Unlikethecrossandrolleruniversaljoint,thetripodjointtrunnionscanslidebackandforthinthechannelsasthejointrotates.Thismaintainsthesamedriveanglethroughthejoint,allowingpowertobetransmittedwithoutspeedfluctuations.InboardCVjointsareusuallytripodjoints.Drive LineRzeppaJointFigure8-9illustratestheRzeppaCVjoint,whichwasinventedin1926byAlfredH.Rzeppa.Itconsistsofaseriesofballsinaslottedcrossandhousingassembly.Duringoperation,theballsslidebackandforthintheslotsasthejointrotates.Sincethedriveanglethroughthejointisnotsubjecttofluctuations,powerflowssmoothlythroughthejointatanyangle.OutboardCVjointsareusuallyRzeppajoints.Figure8-9RzeppaCVjointDrive LineFigure8-8TripodCVjointDrive LineDrive LineFinalDriveTheringandpiniongearsareusedtotransfertheenginepowerfromthedriveshafttotherearwheels.Inadditiontotransferringpower,theringandpinionmustcausethepowertomakea90turnbetweenthedriveshaftandwheels.Theringandpinionmustalsoprovidethecorrectaxleratio.Thepinionisthesmallerdrivinggear;theringisalwaysthelargerdrivengear.DifferentialTherearwheelsofavehiclemustturnatdifferentspeedswhenroundingtheslightestcorner(outsidewheelmustrollfarther).Therearwheelsmustalsobeabletocontinuedrivingthevehiclewhileturningatdifferentspeeds.Therefore,itisnecessarytouseadifferentialtodrivetheaxles,sobothreceivepower,yettheyarefreetoturnatdifferentspeedswhenneeded2.DifferentialOperationThedriveshaftturnstheringgearpinionshaft.Thepiniongearturnstheringgearwhich,inturn,revolvesthedifferentialcase.Whenthecaseturns,thedifferentialpinionshaftturnswithit.Asthedifferentialpinionsaremountedonthisshaft,theyareforcedtomovewiththecase.Beingmeshedwiththesidegears,thepinionswillpullthesidegearsalongwiththem.Whenthevehicleismovinginastraightline,theringgearisturningthecase.Thedifferentialpinionsandsidegearsaremovingaroundwiththecasewithnomovementbetweentheteethofthepinionsandsidegears.Theentiremovementislikeasolidunit.Whenturningacorner,thecasecontinuespullingthepinionsaroundontheshaft.Astheouterwheelmustturnoveralargerarea,theoutersidegearisnowmovingfasterthantheinnersidegear.Thespinningpinionsnotonlypullonbothsidegears,butalsobegintorotateontheirshafts阅读5min后，同学翻译阅读5min后，同学翻译while walk