机械毕业设计英文外文翻译547运动型7速双离合器变速器系统.docx

机械毕业设计英文外文翻译547运动型7速双离合器变速器系统.docx

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机械毕业设计英文外文翻译547运动型7速双离合器变速器系统

附　　录

附录A外文文献原文

7-SpeedDualClutchTransmissionSystemforSportyApplication

ABSTRACT:

Withits7-speeddualclutchtransmission,ZFhasintroducedaninnovativetransmissionforsportyapplications.Thecloseratioscombinedwithextremelyspontaneousdrivebehaviormakesitanidealtransmissionforsportyapplications.Thisarticledescribesthecompactgearsetwithlubricationbyinjectionforimprovingthelevelofefficiencyandincreasingtheengine-speed-strength,thedualclutchunitaswellasthehydrauliccontrolunit,whichisbasedonthepre-controlprinciple,arealsodescribedindetail.Thehy-drauliccontrolprincipleprovidestheoptionofahydrauliccruisemodeintheeventofanelectronicsfailure.Inadditiontothetransmissiondesign,functionalfeaturesthatalsohighlightthesportycharacterofthetransmissionaredescribedindetail.

Keywords:

Automatictransmission;Dualclutch;Vehicleconnection;Efficiency

1Introduction

Whenitcomestothefieldofautomatictransmissions,dualclutchsystemscurrentlyrepresentthebenchmarkintermsofspontaneityandsportiness.Inthistypeoftransmission,whichisbasedonacountershafttransmission,theseadvantagesarecombinedwithaverydirect"vehicleconnection",highrpmperformance,andexcellenttransmissionefficiency.

The7-speeddualclutchtransmissionforthestandarddrivelinepresentedhereisdesignedforatorquecapacityofupto520Nmandrotationalspeedsofupto9250rpms.Inordertobeabletoachievetheseperformancedataintheexistinginstallationspace,aconceptwasdevelopedinwhichanoilchamberaswellaslubricationbyinjectionareused.Beforeintroducingthetransmission′sseveraluniquefeaturesinmoredetailbelow,anoverviewofthebasictransmissiondesignwillbepresented,Fig.1.Theenginetorqueisintroducedtothedualclutchviaatorsiondamper（notshowninFig.1）.Themultidiskclutchesinthedualclutchareradiallynestedinoneanotherandtransferthetorquetobothinputshaftsinthecountershafttransmissiongearset.Inthiscase,duetotheinstallationspace,thecountershaftisnotlocatedunderthemainshaft,butistiltedlaterally.Thisbecomespossiblebecausetheconceptisbasedonlubricationbyinjectionwithadrysump.Ontheonehand,lubricationbyinjectionimprovesheatremoval,ontheother,therearenonoticeablelossesduetothegearssplashingintheoilpan.Theoilissuppliedtothetransmissionviaaninternalgearpumpwhichisdrivenbyaspurgeartrainbehindthedualclutch.Withthehelpofaspurgeartrain,thedriveunithastheadvantagethat,viadifferentgearratiophasesanddependingontheintendeduse,theflowrateandthemax.speedofthepumpcanbeadapted.AnadditionaladvantageisthatbasedontheresultingIprovedinstallationspace,anoptimalratiobetweenthepumpwidthandthepumpdiametercanbeachievedforthepump′slevelofefficiency.Thehydrauliccontrolunitisarrangedunderthegearset.Thehydraulicunitsuppliestheclutch,basedonneed,withpressureandcoolingoilaswellasshiftactuators.Thelatterarearrangedlaterallytothegearsetandworkwithdouble-actingcylinders.Thesensorfordetectingthepositionofthegearshiftsisattacheddirectlyontothefourgearshifts.Thetransmissionhasanexternalcontrolunit.

Fig.1　Overviewdualclutchtransmission（DCT）

2Sevenspeedswithsophisticatedstepping-aconceptforextrmesporti-ness

Thegearsetconceptofthedualclutchtransmissionintroducedherewasdevelopedinhousetakingintoconsiderationthefollowingrequirements:

Highpowerdensity

Highspeedendurancestrengthupto9250rpmVariabilityandmodulardesign

Representationoftransmission-ratiospreadsofabout4.7and6.8with7speeds

Useofexistingsynergiesformanualtransmissions

Afterextensivesystematicdevelopmentofthegearsetinwhichmanythousandsofvariantswereproducedandcompared,thegearsetconceptthatisillustratedinFig.2isthefinalvariantandtheidealconceptforachievingthegoalsspecified.

Thegearsetselectedisbasedontheconstantdriveconceptandconsistsoftwoconcentricdriveshaftseachofwhicharedrivenbyoneofthetwomultidiskclutchesinthe

Fig.2　Gearsetschemeof7Dvariant

dualclutch,twocountershaftsalsoconcentrictooneanother,amainshaftandanoutputshaft.ThegearratiosareengagedbythefoursynchronizerunitsA/B,C/D,E/F,andG/H,whicharearrangedonthemainshaftandonthehollowcountershaftandtheseareconnectedtotheloosewheelsortheadjacentshafts.AnimportantfeatureinthegearsetistheconnectabilityofbothcountershaftsthroughtheC/Dsynchronizerunit.IntheDshiftposition,thegearratiosselectedinthiswaycanbedoublyusedwhichreducesconstructioncostscomparedtoconventionaldualclutchgearsets.Similarly,thisfeatureisusedinfirstgearbecausethenthevehicleisstartedupusingthemorepowerfulK1clutch.Becauseofthisdualuseofthelastgearlevelinthetransmissionforthefirstandsecondgear,thedesiredratiostep1-2isachievedthroughthetransmissionratiosofbothconstantdrivephases.

TheuseoftheK1clutchforstartingupinfirstgearresultsinevitablyinthedirectgearalsobeingassignedtotheoddsubsection.Inthiscase,thefifthandseventhgearscanbeselectedasadirectdrive.Withthisfeature,itwaspossibletodevelopamodulargearsetwhich,onjustafewchanges,containstwodifferenttransmissiongearratiovariantswithfundamentallydifferentcharacters.

Forthefirstversion,withanoverallspreadofabout4.7,theseventhgearisselectedasadirectgear（calledthe7Dvariant）.Fig.2showstherelevantgearsetdiagramwiththeperformanceflowsinallspeeds.Duetoitssophisticatedgearsteps,thistransmissionishighlysuitableforverysportyvehiclesthatneedonlya"little"transmissionsteppingduetothehighrotatingengine.Optimaltractivepowercanbeprovidedatanytimeduringvehicleoperation.

Thesecondversionisbasedonthe7Dvariant,however,fifthgearwasselectedasthedirectdrive.Whenmaintainingthetorquemultiplicationratioandinadaptingthetransmissionratioofseverallowergearlevels,yougetthe5Dvariantwithaconsiderablyhighertransmission-ratiospreadforvehicleswithincreasedcomfortdemandsandsimultaneouslyreducedconsumption.

Fig.3illustratesthedesignofthe7Dvariant.Themainsimilaritywithexistingmanualtransmissionsforstandardtransmissionsisnoticeable.Duetothecompactgearsetdesign,thesufficientshaftdimensioningandthefavorablearrangementinproximityofthebearingofthehightransmittingratios,centralbearingglasseswerenotnecessarydespitetheproportionallylargebearingclearance.Overall,onlytwohousingbearinglevelsarenecessarywherethefrontlevelislocatedbehindbothconstantgears.Inaddition,averycompactandinexpensivetransmissiondesigncouldbeimplementedbasedonthebearingconceptselected,especiallyintheareaofthehollowshaft.

Fig.3　SectionalDrawingof7Dvariant

3Thedualclutch

Thecentralmoduleofthishighlytopicaltransmissionconceptisthewetdualclutch.Withabroadspectrumoftechnicalfeatures,itimplementsthefunctionalprovisionsofthetransmissioncontrolunitandthusdistinguishesthespecialcharacterofthistransmissionconcept.

Veryfastdelaytimes,lowinertiaandgood,comfortablefrictionvalueprogressionsfacilitate,verysportyhandlingwithhighlydynamicgearshiftingandcomfortablecruisingatahighlevelofefficiency.Thedualclutchplaceddirectlyonthetransmissioninputacceptstheenginetorquefromthtorsiondamperandfeedsittooneofthetwosubsections,dependingonthesituation.

Safetyconsiderationshaveledtoa"normallopen"design.

Theradialarrangementofthemultidiskpackagerepresentsthebestcombinationofperformancandinstallationspaceneed,Fig.4.

Fig.4　Dualclutch

Carefulliningandoilselectionaswellasintensiveenhancementofthistribologicalsystemaretherequirementsforcomfortandperformanceofthisclutchthroughoutitsservicelife.

Throughintensetestinganddetailedcalculations,itwaspossibletoachieveaveryhighthermaloadingcapacity.Aspartoftheprocess,theliningtype,dimensioning,andgroovingaswellasequaldistributionofthermalloadandoilflowinthemultidiskpackagearedecisivedesignfeatures.

Lowtorquedragevenwithlowtemperaturesaswellashighspeedendurancestrengthsupportcomfortandahighlevelofsportiness,butarealsoimportantsafetyrequirements.

Rotating,centrifugalforce-compensatingclutchcylinderswithhysteresisoptimizedgasketsmaketheclutcheseasytocontrol.Integratedplatespringsreliablyacceptrapidpistonresettingevenathighspeeds.

Inthecaseofanopenclutch,onlytransmissioninputshaftswithverylowadditionalmassinertiaareused.Thissupportsrapidsynchronizingsequencesandalongservicelifeofthesynchronizerunits.

4Thehydrauliccontrolunit

Inthepresentdualclutchtransmission,thehydrauliccontrolunitfulfillsthefollowingtasks:

Actuatingthedualclutch

Shiftingthegearshifts,i.e.engaging/synchronizingthegear

Coolingthedualclutch

Gearlubrication

Emergencystopfunctionincaseofcompletefailureoftransmissionelectronics

Severalfeaturesinthehydrauliccontrolunitaswellascriteriafortheselectionofthecontrolconceptaregoingtobedescribedinmoredetailbelow.

4.1Performance

Theuseofthedualclutchtransmissioninsportyvehiclesdemandshighperformancefromthehydrauliccontrolunit,especiallywithregardtothefirsttwotasksbecausethe