机械毕业设计英文外文翻译585主减速器和差速器Word文档下载推荐.docx

机械毕业设计英文外文翻译585主减速器和差速器Word文档下载推荐.docx

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Allvehicleshavesometypeofdriveaxle/differentialassemblyincorporatedintothedriveline.Whetheritisfront,rearorfourwheeldrive,differentialsarenecessaryforthesmoothapplicationofenginepowertotheroad.

Powerflow

Thedriveaxlemusttransmitpowerthrougha90°

angle.Theflowofpowerinconventionalfrontengine/rearwheeldrivevehiclesmovesfromtheenginetothedriveaxleinapproximatelyastraightline.However,atthedriveaxle,thepowermustbeturnedatrightangles（fromthelineofthedriveshaft）anddirectedtothedrivewheels.

Thisisaccomplishedbyapiniondrivegear,whichturnsacircularringgear.Theringgearisattachedtoadifferentialhousing,containingasetofsmallergearsthataresplinedtotheinnerendofeachaxleshaft.Asthehousingisrotated,theinternaldifferentialgearsturntheaxleshafts,whicharealsoattachedtothedrivewheels.

Fig1Driveaxle

Rear-wheeldrive

Rear-wheel-drivevehiclesaremostlytrucks,verylargesedansandmanysportscarandcoupemodels.Thetypicalrearwheeldrivevehicleusesafrontmountedengineandtransmissionassemblieswithadriveshaftcouplingthetransmissiontothereardriveaxle.Driveinthroughthelayoutofthebridge,thebridgedriveshaftarrangedverticallyinthesameverticalplane,andnotthedriveaxleshaft,respectively,intheirownsub-actuatorwithadirectconnection,buttheactuatorislocatedatthefrontorthebackoftheadjacentshaft

ofthetwobridgesisarrangedinseries.Vehiclebeforeandafterthetwoendsofthedrivingforceofthedriveaxle,isthesub-actuatorandthetransmissionthroughthemiddleofthebridge.Theadvantageisnotonlyareductionofthenumberofdriveshaft,andraisethedrivingaxleofthecommonpartsofeachother,andtosimplifythestructure,reducesthevolumeandquality.

Fig2Rear-wheel-driveaxle

Somevehiclesdonotfollowthistypicalexample.SuchastheolderPorscheorVolkswagenvehicleswhichwererearengine,reardrive.Thesevehiclesusearearmountedtransaxlewithhalfshaftsconnectedtothedrivewheels.Also,somevehicleswereproducedwithafrontengine,reartransaxlesetupwithadriveshaftconnectingtheenginetothetransaxle,andhalfshaftslinkingthetransaxletothedrivewheels.

Differentialoperation

Inordertoremovethewheelaroundinthekinematicsduetothelackofco-ordinationaboutthewheeldiameterarisingfromadifferentorthesamerollingradiusofwheeltravelrequired,inter-wheelmotorvehiclesareequippedwithaboutdifferential,thelattertoensurethatthecardriverBridgeonbothsidesofthewheelwheninrangewithatriptothecharacteristicsofrotatingatdifferentspeedstomeettherequirementsofthevehiclekinematics.

Fig3Principleofdifferential

Theaccompanyingillustrationhasbeenprovidedtohelpunderstandhowthisoccurs.

1.Thedrivepinion,whichisturnedbythedriveshaft,turnstheringgear.

2.Theringgear,whichisattachedtothedifferentialcase,turnsthecase.

3.Thepinionshaft,locatedinaboreinthedifferentialcase,isatrightanglestotheaxleshaftsandturnswiththecase.

4.Thedifferentialpinion（drive）gearsaremountedonthepinionshaftandrotatewiththeshaft.

5.Differentialsidegears（drivengears）aremeshedwiththepiniongearsandturnwiththedifferentialhousingandringgearasaunit.

6.Thesidegearsaresplinedtotheinnerendsoftheaxleshaftsandrotatetheshaftsasthehousingturns.

7.Whenbothwheelshaveequaltraction,thepiniongearsdonotrotateonthepinionshaft,sincetheinputforceofthepiniongearsisdividedequallybetweenthetwosidegears.

8.Whenitisnecessarytoturnacorner,thedifferentialgearingbecomeseffectiveandallowstheaxleshaftstorotateatdifferentspeeds.

Open-wheeldifferentialoneachgeneralusethesameamountoftorque.Todeterminethesizeofthewheeltorquetobeartwofactors:

equipmentandfriction.Indryconditions,whenalotoffriction,thewheelbearingtorquebyenginesizeandgearrestrictionsarehoursinthefriction（suchasdrivingonice）,isrestrictedtoamaximumtorque,sothatvehicleswillnotspinround.Soevenifthecarcanproducemoretorque,butalsoneedtohavesufficienttractiontotransfertorquetotheground.Ifyouincreasethethrottleafterthewheelsslip,itwillonlymakethewheelsspinfaster.

Fig4Conventionaldifferential

Limited-slipandlockingdifferentialoperation

Fig5Limited-slipdifferential

Differentialsettlementofacarintheunevenroadsurfaceandsteeringwheel-drivenspeedataboutthedifferentrequirements;

butisfollowedbytheexistenceofdifferentialinthesidecarwheelskidcannotbeeffectivewhenthepowertransmission,thatis,thewheelslipcanno