>> P.61
A58ABCDEFGHIJKLMWhenmountingnon-separablebearings,theinnerandouterringsarepressedinsimultaneouslybyapplyingacoverplateasshowninFig.27.Itmustneverhappenthattheinnerringispress-fittedtotheshaftbystrikingtheouterring,ortheouterringbystrikingtheinnerring,becausetheracewaysurfacesandrollingelementswillbescratchedorindented.Fig.27Whenpressfitting,thefrictionofthefittingsurfacescanbereducedbyapplyinghighviscosityoiloverthefittingsurfaces.Thepressing-inorpulling-outforcetobeappliedtothebearingisgivenonpageA59.2MountingbyshrinkfittingThismethodisusedwhentheinterferenceisgreatorwhenalargebearingistobefitted.Thehousingisheatedandthermallyexpandedwhenfittingtheouterringtothehousingandtheinnerringisheatedandexpandedwhenfittingittotheshaftallowingthebear-ingtobeseteasilywithinashorttime.Themaximumallowabletemperaturefortheshrinkfitis+120°C,andheatingshouldbeperformedappropriately.Purenon-corrosivemineraloilisrecommendedastheheatingoilforshrinkfit,andinsulationoilfortrans-formersisconsideredtobethebest.Duringcooling,thebearingalsoshrinksintheaxialdirection.Therefore,toensurethatthereisnoclearancebetweenthebearingandtheshoulder,anaxialforcemustbeappliedcontinuouslytothebearinguntilithascooled.Whentheinterferencebetweentheouterringandthehousingisgreat,anexpansionfitmethodinwhichthebearingiscooledusingdryiceorothercoolingagentbeforefittingcanbeused.Immediatelyafterfitting,however,moisturefromtheaireasilycondensesonthebearing.Therefore,itisnecessarytotakepre-ventivemeasuresagainstcorrosion.Fig.26MountingPreparationBeforemountingthebearing,thedimensionsandfil-letsoftheshaftandhousingshouldbecheckedtoensurethattheyconformtospecifications.Bearingsshouldbeunwrappedjustbeforemounting.Incaseofgreaselubrication,bearingsshouldbefilledwithgreasewithoutcleaningthebearings.Eveninthecaseofoillubrication,itisnormallyunnecessarytocleanthebearings.However,whenhighaccuracyisrequiredorwhenusingathighspeeds,thebearingsshouldbecleanedusingcleaningoiltoremovethor-oughlyoilycontents.Thecleanedbearingsshouldnotbeleftalonewithoutanti-corrosiveprecautions,becausebearingscaneasilybecorrodedafteranti-corrosiveagentsareremoved.Lubricatinggreaseisprepackedinsometypesofbearings.Therefore,refertotherelevantsectionforeachbearing.MethodsofmountingMountingmethodsofbearingsaredifferentaccordingtothetypeofbearingandthefit.Ingeneral,mount-ingofneedlerollerbearingsiscomparativelyeasy.However,non-separablebearingswithlargeinterfer-encesshouldbehandledwithgreatcare.1MountingbypressfitSmallandmediumbearingswithsmallinterferencesrequireasmallpressing-inforceformounting,andtheyaremountedusingapressatroomtemperature.Thebearingshouldbepressedincarefully,applyingaforceevenlytothebearingwithafittingtoolasshowninFig.26.Forseparablebearings,theinnerandouterringscanbemountedseparately,andthemountingworkissimple.However,wheninstallingtheshaftandinnerringassemblyintotheouterring,careshouldbetakennottodamagetheracewaysur-facesandrollingelements.1N=0.102kgf=0.2248lbs.1mm=0.03937inch
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