toyotas-new-six-speed-automatic-transmission-a761e

400CommonwealthDrive,Warrendale,PA15096-0001U.S.A.Tel:[phone]Fax:[phone]Web:’sNewSix-SpeedAutomaticTransmissionA761EforRWDVehiclesYoshinobuNozaki,YoshikazuTanakaandHideoTomomatsuToyotaMotorCorp.HiroyukiTsukamotoandFutomiHanjiAisinAWCo.,Ltd.ReprintedFrom:Transmission&DrivelineSymposium2004(SP-1817)2004SAEWorldCongressDetroit,MichiganMarch8-11,2004Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmitted,inanyformorbyanymeans,electronic,mechanical,photocopying,recording,orotherwise,withoutthepriorwrittenpermissionofSAE.Forpermissionandlicensingrequestscontact:SAEPermissions400CommonwealthDriveWarrendale,PA15096-0001-USAEmail:[e-mail]:724-772-4891Tel:[phone]Formultipleprintcopiescontact:SAECustomerServiceTel:877-606-7323(insideUSAandCanada)Tel:[phone](outsideUSA)Fax:[phone]Email:[e-mail]0-7680-1319-4Copyright©2004SAEInternationalPositionsandopinionsadvancedinthispaperarethoseoftheauthor(s)andnotnecessarilythoseofSAE.Theauthorissolelyresponsibleforthecontentofthepaper.AprocessisavailablebywhichdiscussionswillbeprintedwiththepaperifitispublishedinSAETransactions.PersonswishingtosubmitpaperstobeconsideredforpresentationorpublicationbySAEshouldsendthemanuscriptora300wordabstractofaproposedmanuscriptto:Secretary,EngineeringMeetingsBoard,SAE.PrintedinUSA2004-01-0650Toyota’sNewSix-SpeedAutomaticTransmissionA761EforRWDVehiclesYoshinobuNozaki,YoshikazuTanakaandHideoTomomatsuToyotaMotorCorp.HiroyukiTsukamotoandFutomiHanjiAisinAWCo.,Ltd.Copyright©2004SAEInternationalABSTRACTToyotaMotorCorporationhasrecentlydevelopedanewsix-speedautomatictransmission(A761E)forFrontEngineRearWheelDrive(FR)vehicles.Followingthegeneraltrendofincreasedshiftstagesandawiderrangeofgearratios,thissix-speedautomatictransmissionhasbeendevelopedwithattentionpaidtothegearstepsandawiderrangeofgearratios.Bybalancedselectionofclose-ratiogearsinawiderrange,thechangegreatlyimprovesthepowerperformanceandfueleconomyofthevehicle.Tofurtherimprovefueleconomywehaveadoptednewtechnologiessuchaslow-viscosityATF,neutralcontrol,anddecelerationcontrolbyextendingthefuelcutrange(resetspeed).Wehavealsoadoptedaflat-shapedtorqueconverter,smallsolenoids,analuminumoilpumpcover,etc.torealizethelightestsix-speedautomatictransmissionintheworld.Thisautomatictransmissionislowcostduetotheadoptionofthesamegeartrainasthepreviouslydevelopedfive-speedautomatictransmission(A750E).Thispaperdescribesthestructure,features,andperformanceofthisnewlydevelopedautomatictransmission.INTRODUCTIONAtthestartofthe21stcentury,vehiclemanufacturershavepursuedgrowingenvironmentalimprovementssuchasreducedCO2emissionsandincreasedfueleconomy.Tosatisfythesegoals,vehiclemanufacturershavesteadilydevelopedfuelsavingtechnologiessuchasmulti-speedandcontinuouslyvariabletransmissions.Withsuchabackground,wehavedevelopedthenewsix-speedautomatictransmissionforFRvehicles.Thenewautomatictransmissionnotonlysatisfiessocialrequirementsbyadoptingnewfuel-savingtechnologiesbutalsorealizesexcellentdrivabilityandquietnessdesirableinluxuriouspassengervehicles.DEVELOPMENTOBJECTIVESThedevelopmentobjectivesofthisautomatictransmissionareasfollows:1.Improvedpowerperformanceandfueleconomy2.Attaintheworld’ssmallestsizeandlightestweight3.Smoothshiftfeelwithhighresponse4.NoisereductionTable1:SpecificationsofA761ETable2:OperationChartofFrictionElementsFigure2:GearTrainSchematicofA761EFigure1:CrossSectionofA761EOUTLINEOFCONFIGURATIONThissectiondescribesthebasicconfigurationofthisautomatictransmission.Figure1showsthecrosssection,andFigure2showsthegeartrainschematic.Table1showsthegeneralspecifications,andTable2showstheoperationchartofthefrictionelementswithintheA761E.Viewedfromthefront(engineside)ofthevehiclethereisanultra-flattorqueconverter,oilpump,fourclutches(C1,C2,C3,andC4)inmultiplestructure(Figure3),followedbya6-speedgeartrainconsistingofthreeplanetarygearsets(front,centerandrear),one-wayclutches(F4,F2,F1andF3fromthefront),brakes(B3,B1,B2,andB4)aroundtheplanetarygearsets,andahydrauliccontrolsystemunderneath.Figure3:MultipleStructureofClutchesThegeartrainisbasicallythesameasthatofthefive-speedautomatictransmission(A750E).60%ofallcomponentsarecommonwiththefive-speedautomatictransmission(A750E),and95%ofthepartsusecommonprocessingmachines.Useofcommonpartsandtoolinghasrealizedanappreciablecostreduction.Themajordifferencefromthefive-speedautomatictransmission(A750E)isthemultipleclutchstructure.TheC4clutchisaddedtodividethefunctionoftheC1clutchintheA750Eintotwoclutches(C1andC4).TheF4one-wayclutchisaddedbetweenC1andthecenter/rearsungearmembertolimitclutch-to-clutchshiftsonlybetweenthe5thand6thspeeds.Thisstructuraldesignhasrealizedasix-speedautomatictransmission,whilehavingminimalsizeandweight,canhandleanyenginetorqueupto500N·m.Alsotheaxiallengthandcasediameterarekeptequivalenttothoseoftheconventionalfive-speedautomatictransmission(A650E)toallowinstallationonexistingvehicleswithoutrequiringany