>> P.142
D3■TypesMachinedTypeNeedleRollerBearingsareavailableinvarioustypesshowninTable1.CagedNeedleRollerBearingsThistypeofbearingcombinesacollaredouterringwiththeIKO'suniquelightweightrigidcageandnee-dlerollers.Duringoperation,needlerollersareguid-edpreciselybythecage,andanidealloaddistribu-tionisobtained.ThemetricseriesconsistsoftheNA48andNA49seriesofISOStandard,NA69andTAFIserieswhicharebasedontheinternationaldimensionseries,andtheheavydutyTRIserieswhichiswidelyusedinJapan.TheTAFIserieshasasectionalheightaslowasthatoftheshelltypeandisusedforlightloads.TheinchseriesorBRIseriesisbasedonthespecifi-cationsofANSIStandardofUSA.CagedNeedleRollerBearingswithoutInnerRingAsshowninthesection"Designofshaftandhousing"onpageA44,anydesiredradialclearancecanbeselectedbyassemblingthistypeofbearingwithashaftwhichisheat-treatedandfinishedbygrinding.Thesebearingsarefreefromtheeffectsondimen-sionalaccuracycausedbyassemblinganinnerring,sothattherotationalaccuracyisimproved.Also,theshaftrigiditycanbeimprovedastheshaftdiametercanbeincreasedbyanamountcorrespondingtotheinnerringthickness.CagedNeedleRollerBearingswithInnerRingThistypeofbearingisusedwhentheshaftcannotbeheat-treatedandfinishedbygrinding.Theouterandinnerringsareseparableandasmallreliefclearanceisprovidedonbothsidesoftheinnerringracewaytofacilitatebearingmounting.IntheTRIandBRIseries,thewidthoftheinnerringislargerthanthatoftheouterring.Duetoheatexpansionduringoperationormountingerrors,theinnerorouterringmaybeshiftedaxiallyandthewholelengthoftherollersmaynotbeincon-tactwiththeraceway.Therefore,attentionshouldbepaidtotheallowableaxialshiftSasshowninthetableofdimensions.NeedleRollerBearingswithSealThesebearingsaresealedtypesoftheNA49,NA69andBRIseriesbearings,inwhichasealisinstalledononeside(typewithoneseal)orbothsides(typewithtwoseals)ofthebearing.Thesealismadeofspecialsyntheticrubberandeffectivelypreventsdustpenetrationandgreaseleakage.GuideNeedleRollerBearingsThesebearingsarefullcomplementtypebearingsandusemallet-shapedrollerswhichareguidedaccu-ratelybytheguideraillocatedatthecenteroftheouterringracewayandtheguidegrooveofthemallet-shapedroller.Thisminimizesskewing(tiltingoftherollerfromitsrotatingaxis),whichisnormallyaweakpointoffullcomplementbearings,andimprovestherotationalaccuracy.Thistypeofbearingisespeciallysuitableforheavyloads,shockloadsandoscillatingmotions.Bearingswithandwithoutinnerringsareavailable.Inbearingswithaninnerring,thewidthoftheinnerringislargerthanthatoftheouterring.Table1.1Typeofbearing(Standardtype)TypeSeriesInchseriesDimensionseries49Dimensionseries69Dimensionseries48ForheavydutyForlightdutyRNA49RNA69RNA48TRTAFBRNA49NA69NA48TRITAFIBRIGTR--GTRICagedNeedleRollerBearingsGuideNeedleRollerBearingsWithoutinnerringWithinnerring(1)WithoutinnerringWithinnerring(1)MetricseriesTable1.2Typeofbearing(Withseal)TypeSeriesInchseriesDimensionseries49TwosidesealsOnesidesealTwosidesealsOnesidesealTwosidesealsOnesidesealDimensionseries69RNA49…UURNA49…URNA69…UURNA69…UBR…UU-NA49…UUNA49…UNA69…UUNA69…UBRI…UU-------CagedNeedleRollerBearingsGuideNeedleRollerBearingsWithoutinnerringWithinnerring(1)WithoutinnerringWithinnerring(1)MetricseriesNote(1)orMachinedTypeNeedleRollerBearingswithInnerRings,theNeedleRollerBearingsandInnerRingswillbedeliveredseparately.Ifproductisneededasoneunit,pleasecontactIKO.
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