>> P.72
B5■FitAstheouterringisthin,thecorrectdimensionsandaccuracyofShellTypeNeedleRollerBearingsareobtainedonlyaftertheyhavebeenpress-fittedintothehousingbore.Bearingaccuracyisdirectlyaffect-edbyhousingdimensions,shapeandrigidity.Thisshouldbetakenintoaccountwhenconsideringfitandaccuracy.Theradialclearanceafterfittingthebear-ingtotheshaftandthehousingborevarieswiththeirtolerances.Table4showstherecommendedfitforShellTypeNeedleRollerBearings.Table5showsacalculationexampleofradialclear-anceafterfitting.Thiscalculationappliestobearingswithoutinnerringtobefittedintorigidsteelorcastironhousings.Whenthehousingismadeoflightalloyorathinsteelpipe,itisnecessarytocheckdimensionsbyactualmeasurement.Generally,whenmakingtheradialclearancesmaller,itisrecommendedthattheshaftdiameterbeincreased,withoutdecreasingthehousingborediam-eter.Table4RecommendedfitTable5CalculationexampleofradialclearanceafterfittingTypeofbearingTA…Z,BA…Z,BHA…Z,TAM,BAM,BHAM,YT,YB,YBHTLA…Z,TLAM,YTL,TLA…UUHousingmaterialSteelCastironh6h6h6h6k5(j5)k5(j5)k5(j5)k5(j5)J7M7(N7)N7R7(S7)Lightalloy(Thinsteelpipe)SteelCastironLightalloy(Thinsteelpipe)ToleranceclassShaft(1)WithoutinnerringWithinnerringHousingboreNote(1)Whenhousingsaremadeoflightalloyorathinsteelpipe,therollersetborediameterisgreatlyaffectedbythehousingthicknessandshape.Therefore,beforemass-productionassembly,assemblytestsshouldbecarriedouttoconfirmtheamountofdimensionalchangeandtodeterminethetoleranceoftheshaftwhichwillgivenormalclearances.CalculationprocedureDimensionofhousingboreMax.valueofhousingbore(Dmax):Seethedimensiontable.Min.valueofhousingbore(Dmin):Seethedimensiontable.Dimensionofrollersetborediameterofbearingafterithasbeenpress-fittedintothehousingboreMax.valueofrollersetboredia.(Fwemax)=(Dmax-D0)+FwmaxMin.valueofrollersetboredia.(Fwemin)=(Dmin-D0)+FwminDimensionofshaftMax.valueofshaftdia.(Fmax):Seethedimensiontable.Min.valueofshaftdia.(Fmin):Seethedimensiontable.RadialclearanceaftermountingMax.valueofradialclearance(Grmax)=Fwemax-FminMin.valueofradialclearance(Grmin)=Fwemin-FmaxFromTable2.1onpageB4D0=25.972Fwmax=20.028Fwmin=20.007FromthedimensiontableonpageB14,Dmax=25.993Dmin=25.972Fromtheequations,Fwemax=20.049Fwemin=20.007FromthedimensiontableonpageB14,Fmax=20.000Fmin=19.987Fromtheequations,Grmax=0.062Grmin=0.007Theradialclearanceaftermountingbecomes0.007~0.062mm.ExampleofTLA2020Zunit: mmD:HousingborediameterFw:RollersetborediameterF:ShaftdiameterGr:RadialclearanceFGFwDrDimensionofrollersetborediameterofbearingafterithasbeenpress-fittedintotheringgauge.Dimensionofringgauge(D0):SeeTables2.1and2.2onpageB4.Max.valueofrollersetboredia.(Fwmax):No-godimensionofpluggaugeMin.valueofrollersetboredia.(Fwmin):Godimensionofpluggauge1235
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