>> P.29
usageenvironments•LifeWhilethedefinitionoflifeincludestheratinglifeofficiallyindicatedinJISB1518,nothingelseisuniversallydetermined,anditmaybedefinedinvariouswaysaccordingtotheusageapplicationorindividuallyrequiredperformance(degreeofdeteriorationwithregardtonoise,torque,runout,etc.).Notethatlifeingeneralmayrefertoratinglife(materialfatiguelife),modifiedratinglife,functionallife(performanceconcerningnoise,torque,vibration,etc.),lubricationlifeetc.Operatingenvironment•Temperature,humidity,powder,externalvibration,etc.Decideonthebearingmaterial,retainer,lubricant,etc.basedontheexpectedupperandlowerlimitvaluesoftheoperatingenvironmenttemperatureandhumidity.Decideonwhethertoselectashieldorsealstructurebasedonthepresenceofpowder,andconsiderpreloadaswellaslubricanttypeandamountbasedonexternalvibrationconditions.•OtherspecialenvironmentsForspecialoperatingenvironments,suchasthosewithexposuretospecificchemicalsorgasesortosaltwater,thosewherebearingsmustnotproducepowder,orthosewhereelectricityistobeconductedwithinthebearing,consultMinebeaMitsumi.29