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FrictionLubricationFrictionoflinearmotionrollingguideObjectivesoflubricationThestaticfriction(start-upfriction)oflinearmotionrollingguidesismuchlowerthanthatofconventionalplainguides.Also,thedifferencebetweenstaticfrictionanddynamicfrictionissmall,andfrictionalresistancevarieslittlewhenvelocitychanges.Theseareexcellentfeaturesoflinearmotionrollingguides,andaccountfortheirabilitytoreducepowerconsumption,suppressoperatingtemperaturerise,andincreasetravelingspeed.Sincefrictionalresistanceandvariationaresmall,highspeedresponsecharacteristicstomotioncommandsandhighaccuracypositioningcanbeachieved.FrictioncoefficientThefrictionalresistanceoflinearmotionrollingguidesvarieswiththeirmodel,appliedload,velocityandcharacteristicsoflubricant.Generally,lubricantorsealsaremajorfactorsindeterminingthefrictionalresistanceinlightloadorhighspeedoperation,whiletheamountofloadisthemajorfactorinheavyloadorlowspeedoperation.Thefrictionalresistanceoflinearmotionrollingguidesdependsonvariousfactors,butgenerallythefollowingformulaisused.Theobjectivesofapplyinglubricantforlinearmotionrollingguidesistokeepraceways,rollingelements,etc.inalinearmotionrollingguidefrommetalcontact,andtherebyreducefrictionandwearpreventingheatgenerationandseizure.Whenanadequateoilfilmisformedattherollingcontactareabetweentheracewaysandrollingelements,thecontactstressduetoloadcanbereduced.Tomanagetheformationofadequateoilfilmisimportantforensuringthereliabilityoflinearmotionrollingmechanism.SelectionoflubricantToobtainthefullperformanceoflinearmotionrollingguides,itisnecessarytoselectanappropriatelubricantandlubricationmethodbyconsideringthemodel,loadandvelocityofeachlinearmotionrollingguide.However,ascomparedwithplainguides,lubricationoflinearmotionrollingguidesismuchsimpler.Onlyasmallamountoflubricationoilisneededandreplenishmentintervalislonger,somaintenancecanbegreatlyreduced.Greaseandoilarethetwomostcommonlyusedlubricantsforlinearmotionrollingguides.(3)GreaselubricationTable5FrictioncoefficientTable6Pre-packedgreaselistSeriesnameDynamicfrictioncoefficientμ(1)SeriesnameF=μPwhere,F:Frictionalresistance,Nμ:DynamicfrictioncoefficientP:Appliedload,NForsealedguides,sealresistanceisaddedtotheabovevalue,butthisresistancevariesgreatlydependingontheinterferenceamountofseallipandlubricationconditions.Wherethelubricationandmountingconditionarecorrectandtheloadismoderate,thefrictioncoefficientsoflinearmotionrollingguideinoperationarewithintherangeshowninTable5.Generally,frictioncoefficientislargeundersmallload.CrossedRollerWayLinearSlideUnitLinearBallSplineLinearBushingStrokeRotaryBushingRollerWayFlatRollerCage0.0010～0.00300.0010～0.00200.0020～0.00400.0020～0.00300.0006～0.00120.0020～0.00400.0010～0.0030Note(1)Thesefrictioncoefficientsdonotincludeseal.Ⅲ-7Forlinearmotionrollingguides,lithium-soapbasegrease(ConsistencyNo.2ofJIS)iscommonlyused.Forrollingguidesoperatingunderheavyloadconditions,greasecontainingextremepressureadditivesisrecommended.Incleanandhigh-vacuumenvironments,wherelowdustgeneratingperformanceandlowvaporizationcharacteristicsarerequired,greasescontainingasynthetic-baseoilorasoapotherlithium-soapbaseareused.Forapplicationsintheseenvironments,dueconsiderationisnecessarytoselectagreasethatissuitablefortheoperatingconditionsoflinearmotionrollingguideandachievessatisfactorylubricationperformanceatthesametime.thanthePre-packedgreaseAlvaniaEPGrease2C-LubeLinearBallSplineMAGLinearBallSplineG[ShellLubricantsJapanK.K.]GreasereplenishmentintervalThequalityofanygreasewillgraduallydeteriorateasoperatingtimepasses.Therefore,periodicreplenishmentisnecessary.Greasereplenishmentintervalvariesdependingontheoperatingconditions.Asixmonthintervalisgenerallyrecommended,andifthemachineoperationconsistsofreciprocatingmotionswithmanycyclesandlongstrokes,replenishmenteverythreemonthisrecommended.Inaddition,linearmotionrollingguidesinwhichthelubricationpart"C-Lube"long-termmaintenancefreeperformance.Thiseliminatestheneedforlubricationmechanismandworkloadwhichusedtobenecessaryforlinearmotionrollingguidesandsignificantlyreducesmaintenancecost.isbuiltdeliver
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