>> P.38
1-4BearingSelection(6)Ratingloadandlife•FatiguelimitloadCuThismeanstheloadonthebearingwhichleadstofatiguelimitstressatthemaximumloadcontactpartoftheraceway.Itdependsonthebearingmodel,internalspecifications,quality,andmaterialstrength;forgenerallyusedhigh-qualitybearings,werecommend1500MPaascontactstressequivalenttoCu.(Fatiguelimitstress:Themaximumstressatwhichfatiguedoesnotoccurinthebearingmaterial)•ContaminationcoefficientecIfthelubricantiscontaminatedwithsolidparticles,whichenterbetweentheracewayandtherollingelements,theracewaymaybedented.Thisindentationleadstolocalizedstressincrease,shorteningtherollingbearinglife.Thiscoefficientallowsforthisshortenedlife.Asanindicator,thefollowingisexcerptedfromtheregulationsinJISB1518:2013.ContaminationcoefficientecindicatorsContaminationlevelExtremelyhighcleanlinessHighcleanlinessStandardcleanlinessLightcontaminationNormalcontaminationSeriouscontaminationExtremecontaminationec10.8~0.60.6~0.50.5~0.30.3~0.10.1~00•ViscosityratioκExpressestheseparationstatusofthelubricantfromtherollingcontactsurface,asaratiooftheoilviscosityatactualoperatingtemperaturestothereferenceviscosity.Note:Whencalculatingmodifiedratinglife,variousrestrictionsapply;inaddition,thecalculationmaynotbeentirelyapplicabletominiaturebearings.Becauseofthecomplexconditionswhichmustbeconfirmed,involvingnumerousfactorsincludingdevicedesign,usageapplication,operatingenvironmentandsoon,thecalculationresultsmustbehandledwithsufficientforesightandverification.BearingbasicstaticradialloadratingandstaticequivalentradialloadareregulatedinJISB1519"Staticloadratingsforrollingballbearings."BasicstaticradialloadratingC0rDefinedas"thestaticloadatwhichthecalculatedcontactstressis4200MPaatthecontactcenterofaballandracewayatmaximumload."Thetotalpermanentdeformationoftheballandracewayunderthiscontactstressisroughly0.0001oftheballdiameter.Thebasicstaticradialloadratingisindicatedinthedimensiontables.38
| < 
| 
> | 
>>
