>> P.142
■TypesMachinedTypeNeedleRollerBearingsareavailableinvarioustypesshowninTable1.sothattherotationalaccuracyisimproved.Also,theshaftrigiditycanbeimprovedastheshaftdiametercanbeincreasedbyanamountcorrespondingtotheinnerringthickness.CagedNeedleRollerBearingswithInnerRingThistypeofbearingisusedwhentheshaftcannotbeheat-treatedandfinishedbygrinding.Theouterandinnerringsareseparableandasmallreliefclearanceisprovidedonbothsidesoftheinnerringracewaytofacilitatebearingmounting.theTRIandBRIseries,thewidthoftheinnerringislargerthanthatoftheouterring.Duetoheatexpansionduringoperationormountingerrors,theinnerorouterringmaybeshiftedaxiallyandthewholelengthoftherollersmaynotbeincon-tactwiththeraceway.Therefore,attentionshouldbepaidtotheallowableaxialshiftSasshowninthetableofdimensions.InNeedleRollerBearingswithSealThesebearingsaresealedtypesoftheNA49,NA69andBRIseriesbearings,inwhichasealisinstalledononeside(typewithoneseal)orbothsides(typewithtwoseals)ofthebearing.Thesealismadeofspecialsyntheticrubberandeffectivelypreventsdustpenetrationandgreaseleakage.GuideNeedleRollerBearingsThesebearingsarefullcomplementtypebearingsandusemallet-shapedrollerswhichareguidedaccu-ratelybytheguideraillocatedatthecenteroftheouterringracewayandtheguidegrooveofthemallet-shapedroller.Thisminimizesskewing(tiltingoftherollerfromitsrotatingaxis),whichisnormallyaweakpointoffullcomplementbearings,andimprovestherotationalaccuracy.Thistypeofbearingisespeciallysuitableforheavyloads,shockloadsandoscillatingmotions.Bearingswithandwithoutinnerringsareavailable.Inbearingswithaninnerring,thewidthoftheinnerringislargerthanthatoftheouterring.Table1.1Typeofbearing(Standardtype)TypeCagedNeedleRollerGuideNeedleRollerBearingsBearingsWithoutinnerringWithinnerring(1)WithoutinnerringWithinnerring(1)SeriesGTRGTRI--NA49NA69NA48TRITAFIBRIDimensionseries49Dimensionseries69Dimensionseries48RNA49RNA69RNA48ForheavydutyForlightdutyInchseriesTRTAFBRMetricseriesTable1.2Typeofbearing(Withseal)TypeCagedNeedleRollerGuideNeedleRollerBearingsBearingsWithoutinnerringWithinnerring(1)------WithoutinnerringRNA49…UURNA49…URNA69…UURNA69…UBR…UUWithinnerring(1)NA49…UUNA49…UNA69…UUNA69…UBRI…UU--Dimensionseries49TwosidesealsOnesidesealDimensionseries69TwosidesealsOnesidesealMetricseriesInchseriesTwosidesealsOnesidesealSeriesNote(1)ForMachinedTypeNeedleRollerBearingswiththeNeedleRollerBearingsandInnerRings,InnerRingswillbedeliveredseparately.Ifproductisneededasoneunit,pleasecontactIKO.CagedNeedleRollerBearingsThistypeofbearingcombinesacollaredouterringwiththeIKO'suniquelightweightrigidcageandnee-dlerollers.Duringoperation,needlerollersareguid-edpreciselybythecage,andanidealloaddistribu-tionisobtained.ThemetricseriesconsistsoftheNA48andNA49seriesofISOStandard,NA69andTAFIserieswhicharebasedontheinternationaldimensionseries,andtheheavydutyTRIserieswhichiswidelyusedinJapan.TheTAFIserieshasasectionalheightaslowasthatoftheshelltypeandisusedforlightloads.TheinchseriesorBRIseriesisbasedonthespecifi-cationsofANSIStandardofUSA.CagedNeedleRollerBearingswithoutInnerRingAsshowninthesection"Designofshaftandhousing"onpageA44,anydesiredradialclearancecanbeselectedbyassemblingthistypeofbearingwithashaftwhichisheat-treatedandfinishedbygrinding.theeffectsondimen-Thesebearingsaresionalaccuracycausedbyassemblinganinnerring,fromfreeD3
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