濕式離合器設(shè)計-含DCT濕式雙離合器【含6張CAD圖紙、說明書】【QX系列】

喜歡就充值下載吧。資源目錄里展示的全都有，下載后全都有，所見即所得，CAD圖紙均為高清圖可自行編輯，文檔WORD都可以自己編輯的哦，有疑問咨詢QQ:1064457796,課題后的【XX系列】為整理分類用，與內(nèi)容無關(guān)，請忽視 Wear 288 (2012) 5461ContentslistsavailableatSciVerseScienceDirectWearjournal homepage: www.elsevier.com/locate/wearApparatusforcontinuouswearmeasurementsduringwetclutchdurabilitytestsNiklasLingestena,PrMarklunda,ErikHglunda,MartinLunda,JoakimLundinb,RikardMkibaDivisionofMachineElements,LuleUniversityofTechnology,97187Lule,SwedenbVolvoConstructionEquipment,Eskilstuna,Swedena r t i c l e i n f oa b s t r a c tArticlehistory:Received23May2011Receivedinrevisedform14February2012Accepted21February2012Available online 1 March 2012Wet clutches are used in many applications today such as automatic transmissions and limited slipdifferentials in cars as well as in heavy duty equipment such as wheel loaders. The present study isconcerned with the wear and engagement behavior ofwet clutches inthe latter type ofapplication. Atest rig isdeveloped inwhich the wet clutch engagement ismonitored during an arbitrary number oftestcycles.This rig has many similarities with the SAE #2 test rig in that they are both inertia type test rigs.However,thetestrigpresentedherehasseveraloriginalpartsfromheavydutyequipmentinproductionincorporated intoit.Thedatacollectionincludesacontinuous measurement ofthepositionofthepistonusedtoapplyforceontheclutchpackinadditiontotheseparatordisctemperatures, hydraulicactuatingpressureandtorquetransfercharacteristics. Themeasurements ofthepistonpositioncanthenberelatedtotheclutchwearduringalongtestseries.Keywords:WetclutchWearTestbenchTribologyTemperaturemeasurement 2012 Published by Elsevier B.V.1. Introductionetal.6intestrigsdesignedspecicallyforthisapplication.ThetemperatureintheclutchseparatordiscswasmeasuredthroughWetclutcheshavebeencriticalcomponentsofautomatictrans-missionsandlimitedslipdifferentialsforseveraldecades.However,phenomenaintheclutchsuchasshudderandtorquetransferfail-urehaspromptedinvestigationsintowetclutchbehavior.Thetwomainmethodsusedarecomputersimulationsoftheclutchbehav-iorandexperimentalinvestigationsusingwetclutchtestrigs.OneofthemostcommonlyreportedmethodsusedinwetclutchstudiesistheSAE#2testrigwhichmainlyfunctionsasaniner-tia dynamometer where a ywheel is accelerated to accumulateenergywhereuponaclutchisengagedtobraketheywheel.Thistest setup allows for measurement of torque transfer propertiesandfrictioncharacteristicsforawidevarietyofoperatingcondi-tionsandhasbeenusedextensivelyinresearch13andisalsofrequentlyusedinindustry.AsimilartestrigwasdevelopedbyHol-gerson4withtheadditionofallowingacontributionbyadrivingtorquetotheenergyinputtotheclutch.InHolgersonstestrigtheclutch temperature was measured using an infrared thermome-ter,allowingforinvestigationsontheinuenceoftemperatureonclutchbehavior.the use of thermocouples which allowed for investigation of thedependenceoffrictioncharacteristicsontemperature.Marklundetal.7usedpin-on-discmethodtodevelopafrictionmodel for purposes of simulating wet clutch behavior. However,thisapproachisnotsuitableforstudyingclutchwearinparticularasdemonstratedbyOstetal.8norisitsuitedforinvestigationsofclutchagingingeneral.Thisisinpartbecauseofthelargedifferenceincontactareatosystemsizeratiointhissetupascomparedtotheclutch.Deterioration of clutch performance during service life is animportant issue, limiting the development towards smaller andmoreefcientclutches.Theclutchagingcanbedividedintotwocategories.OneislubricantagingasinvestigatedbyBerglundetal.9forthelimitedslipclutch.Thesecondisfrictionmaterialaging,includingforexamplewear.GlazingasdescribedbyNewcombetal.10 could be described as a combination of the two where thelubricant degrades due to the high temperature in the interfaceformingsmoothlayeronthefrictionmaterialsurface.Wearinpar-ticularwillseverelyaffecttheclutchcontrolsincethethicknessofclutchdiscsshouldbeconsideredwhenconstructionclutchcontrolalgorithmsandmightaffectthefrictioncharacteristics.For the limited slip differential application, however, the SAE#2testrigisnotsuitableduetothecontinuousslipconditionsoftheclutch.InvestigationsintotheclutchcharacteristicsoflimitedslipdifferentialshasbeenperformedbyMkietal.5andIvanovicWearofwetclutchfrictiondiscshasbeeninvestigatedbeforeusingafewdifferenttechniques.Theearlystagesofwearhasbeenstudiedbymanyauthors3,11,12intermsoftherealcontactareabetweenfrictionmaterialandsteeldisc.Forpurposesoflongtermdurabilityofaclutch,thewearofthefullclutchpackismoreinter-estingasithasmoreofaneffectonhowtheengagementmustbe Correspondingauthor.Tel.:+46920492415;fax:+46920491399.E-mailaddress:par.marklundltu.se(P.Marklund).0043-1648/$seefrontmatter 2012 Published by Elsevier B.V.doi:10.1016/j.wear.2012.02.014N.Lingestenetal./Wear 288 (2012) 546155Fig.1. Thetestriglayout:(1)driveshaft,(2)externalywheel,(3)gables,(4and6)gears,(5)sealingdoor,(7)clutchaxlewithclutchdrumand(8)torquearmwithloadcell.Fig.2. Theassemblyoftheclutchinthetestrig:piston(A),springseat(B),balancepiston(C),pressureplate(D),separatorandfrictiondiscs(EandF),washer(G)andendplate(D).controlled.ThewearoffullclutchpackshasbeeninvestigatedusingtheSAE#2testrig1,3orcustomtestrigssuchastheoneusedbySaitoetal.13.Themethodrequiresthetestrigtobedisassembledregularlyinordertomeasurethewearoftheclutch.However,itispossibletocontinuouslymonitorthewearofaclutchpackusingthesensortechnologiesavailabletoday.Developmentofmoreefcientclutchesrequiresreliabledesigncriteria with regards to the different failure modes of the clutch.Inheavydutyequipment,theenergiesandpowerreleasedintheengagementsaregenerallylargeandplacesanimportantlimitationontheclutchdimensions.Thisworkfocusesonthedevelopmentofawetclutchtestrigwhichhastheabilitytocontinuouslymon-itor the wear in the clutch in addition to the clutch engagementcharacteristics.Theperformanceofdifferentclutchdesignscanbeevaluatedbystudyingthewearandfrictiondatawhichiscollected.Tobeabletostoreenergyinthesystem,thedriveshaft(1)hasanintegratedywheel.Theshaftwasmanufacturedfromasinglepieceofsteeltoobtainawellbalancedshaftwhichwouldminimizetheriskofvibrations.Rotationistransferredfromthedriveshafttotheclutchbyahelicalgearpair(4and6)withthegearratio1.Thegearontheclutchaxle(6)hassplinesmachinedonthehubformountingofthefrictiondiscs.Thedriveshaftisdrivenbyanelectricmotorwhichhasamaximumrotationalspeedof3000rpm.Intotal,thetestrighasamomentofinertiaof0.6318kgm2.Anexternalmass(2)canbeaddedtothedriveshaft.Ifthisisdonethetotalmomentofinertiawillincreaseto0.7375kgm2.The clutch axle (7) is a slightly modied original part from awheelloader.Channelsforoilrunthroughtheshaftforthepur-poseofclutchlubricationandhydraulicclutchcontrol.Theclutchismountedintheclutchdrum.Twosensorsformeasurementofengagementcharacteristicsaremountedthroughholesintherearwalloftheclutchdrum.Duringclutchengagementthetorquearm(8)keepstheclutchaxlestationarywhilepressingagainstaloadcellwhichregisterstorquetransfer.Toallowforassemblyanddisassemblyoftheclutchpackaholewasmadeinthegablenearthegears.Throughthisholethegear(6)andclutchassemblycanberemovedandreplaced.Duringexper-iments the hole is sealed by a steel door (5) which supports theclutchaxle.2. MethodsTo carry out wear studies on wet clutches a new test rig wasdesigned.Themainfocusoftheauthorsistheapplicationofwetclutchesinheavydutyequipmentandthustherequirementsarebasedonclutchusageissuchmachines.Throughconditionsiden-tiedinsuchvehiclesalistofrequirementswascompiled.Thetestrigmustbeableto:TheclutchsetupinsidetheclutchdrumisshowninFig.2.Twofrictiondiscswithinwardsplinesareused,squeezedbetweenthreeseparatordiscswithoutwardsplines(EandF).Theinnersepara-tordiscisloadedbyapressureplate(D)whichisindirectcontactwith a hydraulic piston (A) applying the axial load on the clutchpack.Theouterseparatordiscisincontactwithasteelwasher(G).Thewasherallowsfortheassemblyofthetestspecimensinthestandardclutchdrumontheclutchshaft.Theendplate(H)isposi-tionedoutsideofthewasherandheldinplacewithalockingspring.Betweenthehydraulicpistonandthepressureplate,thereisabal-ancepistonandaspringseat(BandC).Betweenthesecomponentsaspringismountedinordertoreturnthepistontotheoriginalposi-tionwhenthehydraulicpressureisreleased.Thestandardsprings Measurethecontinuouswearoftheclutchpack,thetorquetrans-fer,theclutchtemperatureandclutchrotationalspeed. Use standard size clutch discs from construction equipment inproduction. Achieveengagementenergiesabove260kJ/m2. Finishtheengagementwithin1swithgoodreproducibility. Allowforfeedbackcontrolwithregardstoanyoutputparameter. Allowforeasyandaccurateassembly/disassemblyoftheclutchpack2.1. MechanicsAnillustrationofthecorepartofthetestrigisshowninFig.1.Thestructuralstabilityisprovidedbygables(3)andabottomplateinsteel(AISI1148).Theclutchaxle(7)anddriveshaft(1)aresup-portedbytaperedrollerbearingsinthegablesandeverythingismountedonasteelfoundation.has been replaced by a less stiff wave spring with a linear forcedisplacementbehaviorandthespringconstant48103N/m.There are three separate oil circulation systems active in thetestrig,allusingthesametypeoflubricant.Twoforclutchlubri-cationandcooling,sharingoneoiltank,andonehydraulicsystem56N.Lingestenetal./Wear 288 (2012) 5461Table1Testrigdimensions.ComponentdimensionSizeGablethicknessGableheightGablewidthFlywheeldiameterFlywheelwidthDriveshaftlengthTorquearmlength41mm350mm540mm275mm117mm527mm150mmforclutchengagementwithaseparateoilsupply.Onelubricationsystem and the hydraulic system pump oil into the clutch shaftchannelsthroughanoildividermountedonthepreviouslymen-tioneddoor.Anoillterforthelubricationoilisalsomountedonthe door as well as the solenoid servo valve which controls theengagementpressure.Thelubricationoiltankhasavolumeof20l.Theoilispumpedbyxeddisplacementgearpumpsthroughthetwocirculationsys-tems, both of which has a maximum ow rate of 10l/min. Theprimarycirculationsystempumpthelubricantthroughtheclutchaxleintothefrictioninterface,whileaverysmallfractionoftheoil is directed to lubricate the bearings of the drive shaft. In thesecondarycirculationsystem,oilispumpedthroughalterandaheatexchangerwheretheoiltemperatureiscontrolledbymeansofwatercooling.ThereisalsoapossibilitytoheattheoilinthetankFig.3. Schematicofpositionsensormeasurementsetup.testserieswillyieldinformationaboutthethicknesschangeoftheclutchpack,thusyieldinginformationaboutwear.The hydraulic actuating pressure which controls the clutchengagementiscontinuouslymeasuredbyapressuresensorwhichisalsomountedatthebackoftheclutchdrum.Thesensormeas-uresrelativepressureincreasewitharesponsetimelessthan1ms.Thepressuremeasurementisdirectlyrelatedtotheaxialforceandclutchdiscfacepressurethroughthepistonarea.Therotationalspeedofthesystemismeasuredbyamechanicalcounter built into the electric motor that accelerates the rig. Foronerevolutionoftheshaft,4096pulsesaresentfromthemotor.Asettimeintervalisspeciedandthenumberofpulsesarecountedwithinthisinterval,givingtherotationalspeed.Inthisinvestiga-tion,thenumberofpulsesweresampledatarateof100Hz.usingasuspensionheaterallowingforcontrolofthetesttemper-aturewithavariationlessthan2C.ThedimensionsofthetestrigissummarizedinTable1.2.2. SensorsA number of different sensors are installed in the rig to mea-suretheclutchcharacteristics.ThesensorworkingrangesandtheirresolutionissummarizedinTable2.2.3. DataretrievalandsystemcontrolTheverticaltorquearmisindirectcontactwithaloadsensor.Thesensorismountedinaholderattachedtothebottomplate.Theloadcelloutputvoltageisconvertedtoloadinthecontrolsoftware.Thetemperatureismeasuredintheseparatordiscsbytheuseofthermocouples(typeK).Thesethermocouplesaremetalsheathedwithadiameterof0.5mmwithaspeciedresponsetimeof14ms.Theshortresponsetimeallowsforthecaptureofthefastchangesintemperatureduringclutchengagement.Onethermocoupleisalsousedtomonitortheoiltanktemperature.Onethermocoupleisinstalledineachseparatordisc.Thether-mocouplesareinsertedintoholesofdiameter0.8mmdrilledfromtheseparatordiscedges.Threedifferentmaterialsweretestedintheinterfacebetweenthethermocoupleandtheholewallintermsoftemperatureresponseperformance.MaterialoneissimplytheATF which will ll the gap between thermocouple and disc wallduringtestrigrunning.Materialtwoisaregulartinbasedsolder.ThetestrigiscontrolledbyaCompactRiocomputerthroughaLabViewinterfacerunningonaPC.Thecomputerinturncontrolsseveralsubsystems;electricmotorcontroller,thehydraulicpumpandvalves,thepumpsforthecoolingandlubricationoftheclutch.Thehydraulicpumpandvalvecontrollingclutchengagementisswitchedonandoffthroughsimpledigitalswitchesinthecontrolprogram. In the current setup, the hydraulic pump yields a sys-tem pressure of 5 MPa. The servo solenoid valve controlling theactuatingpressureiscontrolledthroughafeedbackloopincludingacontrolchannel.Anysensorreadingcanbeusedasthecontrolchannel, but in the present cases the actuating pressure readinggovernsthevalveaction.Thepressuresensorreadingiscomparedtothedesiredpressureandcombinedintoacontrolvoltagefedtothevalve.Theresponsetimeforthevalveislessthan5ms,allowingforprecisecontroloftheactuatingpressure.Material three is a gallium alloy which is in liquid state at roomtemperature with a boiling point higher than 1350C. This alloyis commercially available under the name Coollaboratory LiquidPro with application as thermal interface material for computerprocessors.The position of the piston (Fig. 2H) as the clutch engages ismeasuredbyacontactDVRT(differentialvariablereluctancetrans-ducer)sensor(Fig.3)mountedatthebackoftheclutchdrum.Thesensorpinisspringloadedandfollowsthepistonasitmoves.Themaximumlengthofmovementthatcanbemeasuredbythesen-sor is 6mm and it gives resolution down to single micrometers.Theoutputisavoltagethatiscalibratedagainstatestcurveandinterpretedinthepostprocessingofexperimentaldata.Thechangein distance traveled by the piston during an engagement over aThetestrigcanrunintwomodes.Onewhereeverythingiscon-trolledmanuallyandonewhichisasequencebasedrunningmode.Inthesecondmode,atestsequencecanbespeciedandsettoruna number of clutch engagements. This mode is ideal for runningextendedweartestsonaclutchpack.Themanualcontrolismainlyusefulfortestingsensorsandtestrigfunctionality.Thecomputeralsohandlesthedataretrieval,savingthedataonanexternalharddriveinbinaryform.Dataisonlystoredduringtheactualclutchengagement,whichlastsforapproximately1s.Thesystemsamplesthedataatarateof2000Hz,enoughtoresolveallthephenomenapresentduringtheengagement.Parallel to the control system, there is a security systemincluding relays to switch off power if the temperature or actu-ating pressure exceeds a preset value. There are also relays for