>> P.54
D1DD2I12Δ121-4BearingSelection(10)Fits•OuterringandhousinginterferencefitsOuterringouterdiameterbeforepress-fittingFig.10-2isasimplediagramshowingbefore(dottedline)andafter(solidline)fitting.WhentheouterringgroovediameterD1ispress-fitwithinterferenceI,Δdecreases.Thatis,Δistheamounttheradialclearancedecreasesduetothefit.Housinginnerdiameterbeforepress-fittingOuterringinnerdiameterbeforepress-fittingHousingFig.10-222+1-1-1m22DDDD2DD2I22+1-1-1mb+EbE11DDDDΔ=(D2/D)2-1DD1D2:Nominalouterringouterdiameter,nominalhousinginnerdiameter:Outerringgroovediameter:HousingouterdiameterIEhmh:Interference(I/2inradialdirection):Young'smodulusofhousing:Poisson'snumberofhousingCalculatingpress-fitforceandremovalforceThepress-fitforcewhenmountingthebearingtotheshaftorhousingwithinterferenceiscalculatedthroughthickcylinderfittheory.Press-fitforce(orremovalforce)isdeterminedbythesurfaceareaandsurfacepressureofthefitsurfaceandthefrictioncoefficient.Press-fitforce(orremovalforce)Kisexpressedwiththefollowingformula.BΔdEkk0d0:Nominalbearingwidth(mm):Effectiveinterference(mm):Longitudinalmodulusofsteel(MPa)E=208000MPa:Innerringthicknessratiok=d/Di:Hollowshaftthicknessratiok0=d0/dForsolidshaft,k0=0:Hollowshaftinnerdiameter(mm)Forsolidshaft,d0=0μ=0.12(whenpress-fittingtheinnerringintothecylindricalshaftandtheouterringintothehousing)μ=0.18(whenremovingtheinnerringfromthecylindricalshaftandtheouterringfromthehousing)(1-K2)(1-K02)1-k2×k02×d2Δ×2EPm=Pm:Surfacepressure(MPa)d:Shaftdiameter(mm)K=μPmdB(N)μ:Fitsurfacefrictioncoefficient54
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