>> P.55
A52ABCDEFGHIJKLMthebearingrotatestogetherwiththebearingforminganairwall.AsshowninFig.24,thejetfromthenoz-zleblowsdirectlyintothespacebetweentheinnerringandthecage.Duetothelargeamountofoilbeingused,itismoreeffectivetomakethedischargeportlarger,andusetheforceddischarge.Whenthedmnvalue(meanvalueofthebearingout-sideandborediametersinmillimeterxrotationalspeedinmin-1)ismorethan1,000,000,thespeedofthejetshouldbe10〜20m/s,thenozzlediametershouldbeabout1mm,oilsupplypressureshouldbe0.1〜0.5MPa,andtheoilsupplyamountshouldbeabout500cc/minorgreater.Whentherotationalspeedishigher,theoilsupplypressureandtheoilamountshouldbehigher.LubricantsForrollingbearings,lubricatinggreaseoroilisgener-allyused.Forspecialapplications,solidlubricantsareused.LubricatinggreaseGreaseisasemi-solidlubricantmadebymixingbaseoil(liquidlubricant)andathickenerunderheatandaddingadditivesasrequired.Therearemanytypesofgreaseaccordingtovariouscombinationsofbaseoil,thickenersandadditives.Greaseisusuallyclassifiedbythickenersandbaseoil.Table35showsthegeneralpropertiesofeachtypeofgrease.ReferenceexamplesofthelubricantgreecebrandandperformanceareshownonpageM46.Excellentunderlowtemperatureconditionsandhassuperiorfrictionalprop-erties.Suitableforsmallbearingsusedinmea-suringinstru-ments.Table35PropertiesofvarioustypesofgreaseName(Commonname)ItemCalciumgreaseCupgreaseSodiumgreaseFibergreaseAluminumgreaseMobilegreaseMixedbasegreaseBariumgreaseLithiumgreaseDiestergreaseSilicongreaseBentonegreaseNon-soapbasegrease(Non-soapgrease)BaseoilThickenerAppearancePourpoint℃Operatigtemperaturerange℃PressureresistanceWaterresistanceMechanicalstabilityFeaturesandapplicationMineraloilCasoapButtery80〜90-10〜+70StrongtoweakGoodFairContainsabout1%water.Whenthetem-peraturerisestomorethan+80°C,thewaterevapo-ratesandthegreasesepa-ratesintooilandsoap.Thisisusedformediumloads.MineraloilNasoapFibrousandbuttery150〜180-20〜+120StrongtomediumPoorGoodMineraloilAlsoapStringyandbuttery70〜90-10〜+80StrongGoodPoorLongfibrousgreasecannotwithstandhighspeeds,buthasgoodpres-sureresis-tanceproper-ties.Shortfibrousgreaseiscompara-tivelygoodforhighspeeds.Ithaswaterandrustresis-tantproper-ties,andadhereseasilytometalsur-face.MineraloilNa+Casoap,Li+CasoapFibrousandbuttery160〜190-10〜+100StrongGood,poorforNa+CasoapgreaseGoodUsableatfairlyhighspeeds.MineraloilBasoapFibrousandbuttery150〜180-10〜+135StrongtomediumGoodPoorIthaswaterandheatresis-tantproper-ties.Thisisanall-purposegrease.MineraloilLisoapButtery170〜190-20〜+120MediumGoodExcellentThisisthebestall-purposegreaseamongsoapbasedgreases.DiesteroilLisoapButtery170〜190-50〜+120MediumGoodExcellentSiliconoilLisoapButtery200〜250-50〜+180WeakGoodExcellentMainlyusedforhightem-peratures.Notsuitedtohighspeedsandheavyloads.MineraloilBentoneButtery200〜-10〜+150MediumtoweakGoodGoodGenerallygoodheatresis-tance.Greasehavingaminer-albaseoilisforgeneraluse.Greasehavingasyntheticbaseoilissuitableforspecialusewheresuperiorheatandchem-icalresistancepropertiesarerequired.SyntheticoilSilicagel.Polyurea,etc.ButteryNone〜+200MediumGoodGoodtopoor()()()()()()Fig.24Oiljetlubrication1N=0.102kgf=0.2248lbs.1mm=0.03937inch
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