>> P.62
A59dd+2dF(){}DismountingDismountingofthebearingsiscarriedoutfortheperi-odicinspectionorrepairsofmachines.Byinspectingthebearing,relatedpartsormechanisms,lubrication,etc.,importantdataisobtained.Inthesamemannerasinmounting,careshouldbetakentopreventdam-agetothebearingorotherparts.Asuitabledismountingmethodshouldbeselectedaccordingtothetypeofthebearing,fit,etc.Bearingsmountedbyinterferencefitareespeciallydifficulttodismount,anditisnecessarytogivedueconsidera-tiontothestructurearoundthebearingduringthedesignstage.DismountingofouterringOuterringsmountedbyinterferencefitaredismount-edasshowninFig.28,byscrewinginthepush-outboltsevenlythroughseveralscrewholesprovidedatplacescorrespondingtothesidefaceoftheouterring.PressingforceandpullingforceGuidelinesforthepressingforcewhenpressingintheinnerringtotheshaftandthepullingforcewhenpull-ingitoutareobtainedfromthefollowingequation.K=fk ∆dfB1-2 ………(39)where, K:Pressingorpullingforce, N fk:Resistancefactordeterminedbythecoefficientoffriction Whenpressingininnerringtoshaft, fk=4×104 Whenpullingoutinnerringfromshaft, fk=6×104d:Borediameterofinnerring, mm∆df:Apparentinterference, mmB:Widthofinnerring, mmF:Outsidediameterofinnerring, mmTheactualpressingforceorpullingforcemaybegreaterthanthecalculatedvalueduetomountingerrors.Whendesigningapuller,itisnecessarythatthepullerhasthestrength(rigidity)towithstandmorethan5timesthecalculatedvalue.RunningtestAftermountingthebearing,arunningtestiscarriedouttocheckwhetherthemountingisnormal.Usually,itisfirstcheckedbymanualturning.Then,itisoperatedbypowergraduallyfromno-loadandlow-speeduptonormaloperatingconditionstocheckforabnormalities.Noisecanbecheckedbyusingasoundscopeorsimi-larinstrument.Inthistest,checksarecarriedoutforthefollowingabnormalities.1Manualturning(a)Uneventorque ……………… Impropermounting(b)Stickingandrattling … Scratchesorindentationsontheracewaysurface(c)Irregularnoise … Penetrationofdustorforeignparticles2Powerrunning(a)Abnormalnoiseorvibration … Indentationsontheracewaysurface,toogreatclearance(b)Abnormaltemperature … Unsuitablelubricant,impropermounting,toosmallclearanceFig.28
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