车辆工程汽车离合器的外文文献翻译.docx

车辆工程汽车离合器的外文文献翻译.docx

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车辆工程汽车离合器的外文文献翻译

湖北文理学院

毕业设计（论文）英文翻译

题目

有限元热分析的陶瓷离合器

专业

车辆工程

班级

Xxx

姓名

Xxxx

学号

2010138xx

指导教师

职称

Xxx副教授

2014年2月25日

Fethermalanalysisofaceramicclutch

1.Introduction

Abrasivedryrunningvehicleclutchesareforceclosurecouplings.Torqueandspeedtransmissionareensuredbythefrictionalforcegeneratedbetweentwopressedsurfaces.Reasonsfortheapplicationofceramicasafrictionmediumincludegoodheatandwearresistanceproperties,whichprovidetheopportunitytodrivehigherpressures,andalowdensity.Thus,anincreasingpowerdensityisenabledwithaparallelminimizationofconstructionspace.

MeasurementswithafirstprototypeofaclutchdiskusingceramicfacingswereperformedatKarlsruheUniversityinalaboratoryspecializedinpassengercardrivesystemtesting.Inthecourseofanalysisthefiniteelement（FE）modelwastobeconstructedwiththeknowledgeofmeasurementdataandmeasurementconditions.Calculationswereintendedtodeterminethetemperaturedistributionoftheclutchdiskanditsenvironmentateachmomentintimecorrespondingtomeasurements.Itisessentialtobefamiliarwiththetemperaturerangeinordertoexaminethewearcharacteristicsofthesystem.Thus,importantinformationisderivedfrommeasurementdata.Incriticalloadcases,thehighestexpectedtemperaturesmustbeforecastinspaceandtimeinordertoprotectmeasuringinstrumentsclosetothelocationofheatgeneration.

Thegoalofthisstudyistoanalyzeandmodifytheclutchsystemtoprovidebetteroperatingconditionsbyimprovingtheheatconductionandconvectionofthesystemortoincreasetheamountoftheenergyconvertedintofrictionalheat.Furthermore,itisdesiredtofindbetterdesignsolutionsformoreefficientclutchsystems.

CalculationswereperformedbytheCosmosDesignStarsoftware.Duringmodeldevelopment,greatcarehadtobetakenforpropersimplificationofgeometry,theselectionofelementsizes,andthecorrectadjustmentoftimestepsduetothesubstantialhardwarerequirementsfortransientcalculations.Changesinthermalparameterssuchasthesurfaceheatconvectioncoefficientandthermalloadhadtobetakenintoconsiderationonanon-goingbasisintermsoftimeandlocation.Thetwosidesoftheanalyzedtestclutchsystemcanonlybemanagedbytwoindependentmodelslinkedbyheatpartition,accordingtothehypothesisthatthecontacttemperaturemustbeidenticalonbothsideswhilethereispropercontactbetweenthemanditsvaluemustbeadjustedbyiteration.Calculationsrevealedthattheheatpartitionchangedbycycleanditdifferedalongtheinnerandoutercontactrings.Asaresultofthedifferentcoolingcharacteristicsbetweentheceramicandsteelside,aheat

flowislaunchedfromtheceramicsidetothesteelside.Thisheatflowwasalsodeterminedbyiteration,itsvaluealsochangesbycycleanddiffersalongtheinnerandoutercontactrings.

2.Firstprototypeofaclutchusingengineeringceramicsasfrictionmaterial

Theexaminedclutchdiskwasdevelopedaccordingtothe“specificceramic”productdevelopmentprocessestablishedattheInstituteforProductDevelopment（IPEK）attheUniversityofKarlsruhe.Thisdevelopmentprocessalreadyhasthepossibilityforconnectiontoarealtransmissionshaft;further,ithasacushionspringdeviceforthefacingsallowinggoodstartbehaviour.Abrasiveclutchesmustcomplywiththefollowingbasicrequirements:

●hightorquetransmissionaccordingtohighfrictioncoefficients,

●highcomfort（novibrationsthroughself-inducedchattering）,

●homogeneoustemperaturedistribution,

●lowwearcharacteristic.

Acriticalelementoftheswitchistheabrasivedisk.Withregardtothedesignutmostcaremustbetakentoselecttherightmaterial.Ahighandconstantfrictioncoefficient,，wearresistanceandthermalresistancearedesiredcharacteristics.Theclutchdiskhasinsteadofthegenerallyappliedring-shapedabrasiveinlettworowsofSSIC（assintered）ceramicpellets.Thesepelletsareplacedon6separatesegments.Thesegmentsarefixedtothecentralhubbyrivets.Eachsegmentconsistsof4plates,2workingasfacingspringsand2ascarriers.

3.Measurements

MeasurementswereperformedatthedepartmentofpowertraindevelopmentoftheInstituteforProductDevelopment（IPEK）attheKarlsruheUniversity（TH）ResearchUniversity,whereacategoryIVcomponenttestrigisusedfortestsofnewfrictionalmaterialsandexaminationsofnewmaterialsinrealclutchdisks.Realconditionsareappliedbythesimulationofdrivingresistance（e.g.startingintheplane,startingatthehill）.Itisacomponenttestrigleveledonthefourthpositionofthetribologicaltestingenvironment.

Inordertogiveanideaofdimensions:

theequipmentlengthisabout4-5m.Thetwoelectricmotorsandtheaxialfo