Proceedingsofthe7thICFDM2006InternationalConferenceonFrontiersofDesignandManufacturingJune19-22,2006,Guangzhou,ChinaTHEHHHSWAGINGGGGGGGTECHNOLOGYHOOGHOOGHOOGUSEDINSHAFTHHHCLINCHINGHGHGHGASSEMBLYFOROOOAUTOMOTIVEOOOOOOHUBHHHBEARINGGGGUNITXiaoYunya1,2,ZhouZhixiong1andLvJianmin31CollegeofMechanicalandAutomotiveEngineering,HunanUniversity,China2DepartmentofElectromechanicalEngineering,ShaoguanUniversity,China3ShaoguanSoutheastBearingCo.,Ltd.,ChinaAbstract:Recently,shaftendclinchingisbeingadoptedinthehubbearingunitassembly,whichwillraiseastechnologicaltrendandgraduallyreplaceclampnutinfuture.Inamachinereconstructedfromlathe,thesampleofshaftendclinchedhubunitissuccessfullymanufacturedbyswagingtechnologywithgivenparameters.Sometestsconfirmthattheshaftendclinchinghubunithasfunctionsgreaterthanthetraditionalhubunitwithclampnut.Intheend,thefutureapplicationandthefurtherresearchdirectionoftheswagingtechnologyarediscussed.KeyKKKWords:hubbearingunit,swaging,shaftclinching,assemblyHubunitbearingsarewidelybeingadoptedforcarsastheyarelighterandstrongerandeasilytomounting.Inthehubbearingunitassembly,theshaftclinchingtighteningreplacesclampnutandbecomestechnologicaltrend.Itisadoptedinthemostlyfamousinternationalcompaniesofbearingmanufacture.However,thedeformationoftheworkpieceinclinchingprocessiscomplexanddifficulttobecontrolled.Itbringsphenomenonssuchasdistortionofstructureintheconnectingarea,shortageofsupportingrigidity,inadequacyofstrength,disqualificationofrotationalaccuracyandlackoflife.Thusleadsthehubunittoinvalidationeasily.Uptonow,theswagingtechnologyusedinshaftclinchingforhubunitisnotwellmastered.Withthesupportfromsomecorporations,thepilotstudyoftheswagingtechnologyiscompleted.Theproblemsfromtechnicsandequipmentofclinchingaresolved,andthesampleofswagededgeofhubbearingunitismanufacturedsuccessfully.1.IntroductionHubbearingunitisassembledfromseveralcomponents,whichispre-adjustedandlubricatedforlife.Theunitwasoriginallydesignedforuseincarsandtruckstoreplacethetraditionaltaperrollerbearings,whichisreadytoinstallandfreemaintenance.Withthehubbearingunitsnotonlythenumberofparts,butalsotheoverallweightofthewheelarrangementisreduced.Theyalsoreduceassemblytimebecausetheydonotrequireanyspecialadjustment.Eachunitisself-containedandreadytobeboltedinplace.ThiskindofbearinghascomethroughthreegenerationssinceitwasdesignedbySKFin1938.The4thgenerationhubunitisnowunderdevelopmentthoughithasnotyetbeenmass-produced.Figure1illustratesthestructureofhubbearingunits3.The1stgenerationhubbearingunitiscomposedoftwosingle-rowbearingswiththeirouterringsintegrated,wheregreaseisfilledwithseals.Comparedwiththe1stgeneration,the2ndgenerationhubbearingunitismuchmorelightweightandminiaturization，whichhasintegratedflangeintotheouterringof1stgenerationwheelbearing.The3rdgenerationhubbearingunitisanadvancedtypeof2ndgeneration,whichtheoutboardinnerringoftheinner-ringrotationtypehubunitandhub-shaftareintegrated.Inthisgenerationhubunit,numberofbuilt-inhigh-performancesensortypehasincreased.2Figure.1HubunitbearingsTofurtherreducetheweightandsizeofthehubbearingunitandimproveitsreliability,NSKhasrecentlydevelopedanovelshaftendclinchinghubunit.Inthenewhubdesign,theclampnutwhichfastenstheinnerandouterringstogetherisreplacedwithaswagededge.Theswagingthatusedinshaftclinchingisatechniquethatdeformstheendpartofhubshaftbyswagingforginginwhichinboardofinnerringandpropershaftforcebythisdeformation.Figure2showsexamplesof3rdgenerationtypeclinchedshafthubunitsforadrivenwheelanddrivewheelrespectively.Inaddition,thistechniqueisalsoapplicabletotheinnerringrotationtype2ndgenerationhubunits2.drivenwheeldrivewheelFigure2ShaftclinchinghubunitThereareseveraladvantagesoftheswagedhubunitincomparisontoconventionalretainingnutassemblies.Thenutissavedintheswagedhubunit.Theswagedhubunitssizeissmallerandweightislessthantheconventionalretainingnutassemblies.Thestructureoftheunitbecomescompact.Andthevehiclefuelconsumptionisreduced1.Theclampingforcecanbecontrolledaccuratelyduringtheswagingprocess.Thentheeffectoferrorfrompartsisavoided.Thefluctuationofpre-adjustedforceisreducedgreatly.Aseveryhubunitgainsthebestpre-adjustedforceafterassembly,thelifeofbearingunitcanbeextended.Theclinchingtighteningisanun-reversibleassembly.Theassemblyisnotfailurethoughthevibrationcausedfromrunningprocessisbeenloadedonthehubunit.Theshaftclinchingprocessiscapabletoperfectlycomplywiththeproblemof“l(fā)ooseningoftightening”thatwasimpossibletobesolvedforthenuttightening.Thentheshaftclinchingimprovesthereliabilityandsafetyoftheproductgreatly.Thistechnologyenablesresourceandenergyofthemanufactureofhubbearingunittob