>> P.315
FrictionLubricationFrictionoflinearmotionrollingguideObjectivesoflubricationThestaticfriction(start-upfriction)oflinearmotionrollingguidesismuchlowerthanthatofconventionalplainguides.Also,thedifferencebetweenstaticfrictionanddynamicfrictionissmall,andfrictionalresistancevarieslittlewhenvelocitychanges.Theseareexcellentfeaturesoflinearmotionrollingguides,andaccountfortheirabilitytoreducepowerconsumption,suppressoperatingtemperaturerise,andincreasetravelingspeed.Sincefrictionalresistanceandvariationaresmall,high-speedresponsecharacteristicstomotioncommandsandhighaccuracypositioningcanbeachieved.FrictioncoefficientThefrictionalresistanceoflinearmotionrollingguidesvarieswiththeirmodel,appliedload,velocityandcharacteristicsoflubricant.Generally,lubricantorsealsaremajorfactorsindeterminingthefrictionalresistanceinlightloadorhigh-speedoperation,whiletheamountofloadisthemajorfactorinheavyloadorlowspeedoperation.Thefrictionalresistanceoflinearmotionrollingguidesdependsonvariousfactors,butgenerallythefollowingformulaisused.F=μP(13)where,F:Frictionalresistance,Nμ:DynamicfrictioncoefficientP:Appliedload,NForsealedguides,sealresistanceisaddedtotheabovevalue,butthisresistancevariesgreatlydependingontheinterferenceamountofseallipandlubricationconditions.Wherethelubricationandmountingconditionarecorrectandtheloadismoderate,thefrictioncoefficientsofLinearWayandLinearRollerWayinoperationarewithintherangeshowninTable10.Generally,frictioncoefficientislargeundersmallload.Table10FrictioncoefficientSeriesnameLinearWayLinearRollerWayDynamicfrictioncoefficientμ(1)0.0040～0.00600.0020～0.0040Note(1)Thesefrictioncoefficientsdonotincludeseal.Theobjectivesofapplyinglubricantforlinearmotionrollingguidesistokeepraceways,rollingelements,etc.inalinearmotionrollingguidefrommetalcontact,andtherebyreducefrictionandwearpreventingheatgenerationandseizure.Whenanadequateoilfilmisformedattherollingcontactareabetweentheracewaysandrollingelements,thecontactstressduetoloadcanbereduced.Tomanagetheformationofadequateoilfilmisimportantforensuringthereliabilityoflinearmotionrollingmechanism.SelectionoflubricantToobtainthefullperformanceoflinearmotionrollingguides,itisnecessarytoselectanappropriatelubricantandlubricationmethodbyconsideringthemodel,loadandvelocityofeachlinearmotionrollingguide.However,ascomparedwithplainguides,lubricationoflinearmotionrollingguidesismuchsimpler.Onlyasmallamountoflubricationoilisneededandreplenishmentintervalislonger,somaintenancecanbegreatlyreduced.Greaseandoilarethetwomostcommonlyusedlubricantsforlinearmotionrollingguides.GreaselubricationForlinearmotionrollingguides,lithium-soapbasegrease(ConsistencyNo.2ofJIS)iscommonlyused.Forrollingguidesoperatingunderheavyloadconditions,greasecontainingextremepressureadditivesisrecommended.Incleanandhigh-vacuumenvironments,wherelowdustgeneratingperformanceandlowvaporizationcharacteristicsarerequired,greasescontainingasynthetic-baseoilorasoapotherthanthelithium-soapbaseareused.Forapplicationsintheseenvironments,dueconsiderationisnecessarytoselectagreasethatissuitablefortheoperatingconditionsoflinearmotionrollingguideandachievessatisfactorylubricationperformanceatthesametime.Table11Pre-packedgreaselistSeriesnamePre-packedgreaseC-LubeLinearWayMLLinearWayLC-LubeLinearWayMLVC-LubeLinearWayMVC-LubeLinearWayMELinearWayEC-LubeLinearWayMH(1)LinearWayH(1)LinearWayFMULTEMPPSNo.2[KYODOYUSHICO.,LTD.]AlvaniaEPGrease2[ShellLubricantsJapanK.K.]C-LubeLinearWayMULLinearWayU(2)C-LubeLinearRollerWaySuperMXLinearRollerWaySuperXLinearRollerWayXLinearWayModuleMULTEMPPSNo.2[KYODOYUSHICO.,LTD.]AlvaniaEPGrease2[ShellLubricantsJapanK.K.]Notes(1)MULTEMPPSNo.2ispre-packedinsize8to12series.(2)AlvaniaEPGrease2ispre-packedinsize40to86series.Ⅲ-21
| < 
| 
> | 
>>
