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附录附录1英文原文ROLLINGCONTACTBEARINGSTHECONCERNOFAMACHINEDESIGNERWITHBALLANDROLLERBEARINGSISFIVEFOLDASFOLLOWSALIFEINRELATIONTOLOAD；BSTIFFNESS,IEDEFLECTIONSUNDERLOAD；CFRICTION；DWEAR；ENOISEFORMODERATELOADSANDSPEEDSTHECORRECTSELECTIONOFASTANDARDBEARINGONTHEBASISOFLOADRATINGWILLBECOMEIMPORTANTWHERELOADSAREHIGH,ALTHOUGHTHISISUSUALLYOFLESSMAGNITUDETHANTHATOFTHESHAFTSOROTHERCOMPONENTSASSOCIATEDWITHTHEBEARINGWHERESPEEDSAREHIGHSPECIALCOOLINGARRANGEMENTSBECOMENECESSARYWHICHMAYINCREASEFRICTIONALDRAGWEARISPRIMARILYASSOCIATEDWITHTHEINTRODUCTIONOFCONTAMINANTS,ANDSEALINGARRANGEMENTSMUSTBECHOSENWITHREGARDTOTHEHOSTILITYOFTHEENVIRONMENTBECAUSETHEHIGHQUALITYANDLOWPRICEOFBALLANDROLLERBEARINGSDEPENDSONQUANTITYPRODUCTION,THETASKOFTHEMACHINEDESIGNERBECOMESONEOFSELECTIONRATHERTHANDESIGNROLLINGCONTACTBEARINGSAREGENERALLYMADEWITHSTEELWHICHISTHROUGHHARDENEDTOABOUT900HV,ALTHOUGHINMANYMECHANISMSSPECIALRACESARENOTPROVIDEDANDTHEINTERACTINGSURFACESAREHARDENEDTOABOUT600HVITISNOTSURPRISINGTHAT,OWINGTOTHEHIGHSTRESSESINVOLVED,APREDOMINANTFORMOFFAILURESHOULDBEMETALFATIGUE,ANDAGOODDEALOFWORKISBASEDONACCEPTEDVALUESOFLIFEANDITISGENERALPRACTICEINTHEBEARINGINDUSTRYTODEFINETHELOADCAPACITYOFTHEBEARINGASTHATVALUEBELOWWHICH90PERCENTOFABATCHWILLEXCEEDALIFEOFONEMILLIONREVOLUTIONSNOTWITHSTANDINGTHEFACTTHATRESPONSIBILITYFORTHEBASICDESIGNOFBALLANDROLLERBEARINGSRESTSWITHTHEBEARINGMANUFACTURER,THEMACHINEDESIGNERMUSTFORMACORRECTAPPRECIATIONOFTHEDUTYTOBEPERFORMEDBYTHEBEARINGANDBECONCERNEDNOTONLYWITHBEARINGSELECTIONBUTWITHTHECONDITIONSFORCORRECTINSTALLATIONTHEFITOFTHEBEARINGRACESONTOTHESHAFTORONTOTHEHOUSINGSISOFCRITICALIMPORTANCEBECAUSEOFTHEIRCOMBINEDEFFECTONTHEINTERNALCLEARANCEOFTHEBEARINGASWELLASPRESERVINGTHEDESIREDDEGREEOFINTERFERENCEFITINADEQUATEINTERFERENCECANINDUCESERIOUSTROUBLEFROMFRETTINGCORROSIONTHEINNERRACEISFREQUENTLYLOCATEDAXIALLYBYABUTTINGAGAINSTASHOULDERARADIUSATTHISPOINTISESSENTIALFORTHEAVOIDANCEOFSTRESSCONCENTRATIONANDBALLRACESAREPROVIDEDWITHARADIUSORCHAMFERTOALLOWSPACEFORTHISWHERELIFEISNOTTHEDETERMININGFACTORINDESIGN,ITISUSUALTODETERMINEMAXIMUMLOADINGBYTHEAMOUNTTOWHICHABEARINGWILLDEFLECTUNDERLOADTHUSTHECONCEPTOF“STATICLOADCARRYINGCAPACITY”ISUNDERSTOODTOMEANTHELOADTHATCANBEAPPLIEDTOABEARING,WHICHISEITHERSTATIONARYORSUBJECTTOSLIGHTSWIVELINGMOTIONS,WITHOUTIMPAIRINGITSRUNNINGQUALITIESFORSUBSEQUENTROTATIONALMOTIONTHISHASBEENDETERMINEDBYPRACTICALEXPERIENCEASTHELOADWHICHWHENAPPLIEDTOABEARINGRESULTSINATOTALDEFORMATIONOFTHEROLLINGELEMENTDIAMETERTHISWOULDCORRESPONDTOAPERMANENTDEFORMATIONOF00025MMFORABALL25MMINDIAMETERTHESUCCESSFULFUNCTIONINGOFMANYBEARINGSDEPENDSUPONPROVIDINGTHEMWITHADEQUATEPROTECTIONAGAINSTTHEIRENVIRONMENT,ANDINSOMECIRCUMSTANCESTHEENVIRONMENTMUSTBEPROTECTEDFROMLUBRICANTSORPRODUCTSOFDETERIORATIONOFTHEBEARINGDESIGNMOREOVER,SEALSWHICHAREAPPLIEDTOMOVINGPARTSFORANYPURPOSEAREOFINTERESTTOTRIBOLOGISTSBECAUSETHEYARECOMPONENTSOFBEARINGSYSTEMSANDCANONLYBEDESIGNEDSATISFACTORILYONTHEBASISOFTHEAPPROPRIATEBEARINGTHEORYNOTWITHSTANDINGTHEIRIMPORTANCE,THEAMOUNTOFRESEARCHEFFORTTHATHASBEENDEVOTEDTOTHEUNDERSTANDINGOFTHEBEHAVIOROFSEALSHASBEENSMALLWHENCOMPAREDWITHTHATDEVOTEDTOOTHERASPECTSOFBEARINGTECHNOLOGYLATHESLATHESAREWIDELYUSEDININDUSTRYTOPRODUCEALLKINDSOFMACHINEDPARTSSOMEAREGENERALPURPOSEMACHINES,ANDOTHERSAREUSEDTOPERFORMHIGHLYSPECIALIZEDOPERATIONSENGINELATHESENGINELATHES,OFCOURSE,AREGENERALPURPOSEMACHINEUSEDINPRODUCTIONANDMAINTENANCESHOPALLOVERTHEWORLDSIZESRANGEFROMSMALLBENCHMODELSTOHUGEHEAVYDUTYPIECESOFEQUIPMENTMANYOFTHELARGERLATHESCOMEEQUIPPEDWITHATTACHMENTSNOTCOMMONLYFOUNDINTHEORDINARYSHOP,SUCHASAUTOMATICSTOPSFORTHECARRIAGETRACERORDUPLICATINGLATHESTHETRACERORDUPLICATINGLATHEISDESIGNEDTOPRODUCEIRREGULARLYSHAPEDPARTSAUTOMATICALLYTHEBASICOPERATIONOFTHISLATHEISASFALLOWSATEMPLATEOFEITHERAFLATORTHREEDIMENSIONALSHAPEISPLACEDINAHOLDERAGUIDEORPOINTERTHENMOVESALONGTHISSHAPEANDITSMOVEMENTCONTROLSTHATOFTHECUTTINGTOOLTHEDUPLICATIONMAYINCLUDEASQUAREORTAPEREDSHOULDER,GROOVES,TAPERS,ANDCONTOURSWORKSUCHASMOTORSHAFTS,SPINDLES,PISTONS,RODS,CARAXLES,TURBINESHAFTS,ANDAVARIETYOFOTHEROBJECTSCANBETURNEDUSINGTHISTYPEOFLATHETURRETLATHESWHENMACHININGACOMPLEXWORKPIECEONAGENERALPURPOSELATHE,AGREATDEALOFTIMEISSPENTCHANGINGANDADJUSTINGTHESEVERALTOOLSTHATARENEEDEDTOCOMPLETETHEWORKONEOFTHEFIRSTADAPTATIONSOFTHEENGINELATHEWHICHMADEITMORESUITABLETOMASSPRODUCTIONWASTHEADDITIONOFMULTITOOLTURRETINPLACEOFTHETAILSTOCKALTHOUGHMOSTTURRETSHAVESIXSTATIONS,SOMEHAVEASMANYASEIGHTHIGHPRODUCTIONTURRETLATHESAREVERYCOMPLICATEDMACHINESWITHAWIDEVARIETYOFPOWERACCESSORIESTHEPRINCIPALFEATUREOFALLTURRETLATHES,HOWEVER,ISTHATTHETOOLSCANPERFORMACONSECUTIVESERIALSOFOPERATIONSINPROPERSEQUENCEONCETHETOOLSHAVEBEENSETANDADJUSTED,LITTLESKILLISREQUIREDTORUNOUTDUPLICATEPARTSAUTOMATICSCREWMACHINESSCREWMACHINESARESIMILARINCONSTRUCTIONTOTURRETLATHES,EXCEPTTHATTHEIRHEADSAREDESIGNEDTOHOLDANDFEEDLONGBARSOFSTOCKOTHERWISE,THEREISLITTLEDIFFERENTBETWEENTHEMBOTHAREDESIGNEDFORMULTIPLETOOLING,ANDBOTHHAVEADAPTATIONSFORIDENTICALWORKORIGINALLY,THETURRETLATHEWASDESIGNEDASACHUCKINGLATHEFORMACHININGSMALLCASTINGS,FORGINGS,ANDIRREGULARLYSHAPEDWORKPIECESTHEFIRSTSCREWMACHINESWEREDESIGNEDTOFEEDBARSTOCKANDWIREUSEDINMAKINGSMALLSCREWPARTSTODAY,HOWEVER,THETURRETLATHEISFREQUENTLYUSEDWITHACOLLETATTACHMENT,ANDTHEAUTOMATICSCREWMACHINECANBEEQUIPPEDWITHACHUCKTOHOLDCASTINGSTHESINGLESPINDLEAUTOMATICSCREWMACHINE,ASITSNAMEIMPLIES,MACHINESWORKONONLYONEBAROFSTOCKATATIMEABAR16TO20FEETLONGISFEDTHROUGHTHEHEADSTOCKSPINDLEANDISHELDFIRMLYBYACOLLECTTHEMACHININGOPERATIONSAREDONEBYCUTTINGTOOLSMOUNTEDONTHETURRETANDONTHECROSSSLIDEWHENTHEMACHINEISINOPERATION,THESPINDLEANDTHESTOCKAREROTATEDATSELECTEDSPEEDSFORDIFFERENTOPERATIONSIFREQUIRED,RAPIDREVERSALOFSPINDLEDIRECTIONISALSOPOSSIBLEINTHESINGLESPINDLEAUTOMATICSCREWMACHINE,ASPECIFICLENGTHOFSTOCKISAUTOMATICALLYFEDTHROUGHTHESPINDLETOAMACHININGAREAATTHISPOINT,THETURRETANDCROSSSLIDEMOVEINTOPOSITIONANDAUTOMATICALLYPERFORMWHATEVEROPERATIONSAREREQUIREDAFTERTHEMACHINEDPIECEISCUTOFF,STOCKISAGAINFEDINTOTHEMACHININGAREAANDTHEENTIRECYCLEISREPEATEDMULTIPLESPINDLEAUTOMATICSCREWMACHINESHAVEFROMFOURTOEIGHTSPINDLESLOCATEDAROUNDASPINDLECARRIERLONGBARSOFSTOCK,SUPPORTEDATTHEREAROFTHEMACHINE,PASSTHROUGHTHESEHOLLOWSPINDLESANDAREGRIPPEDBYCOLLETSWITHTHESINGLESPINDLEMACHINE,THETURRETINDEXESAROUNDTHESPINDLEWHENONETOOLONTHETURRETISWORKING,THEOTHERSARENOTWITHAMULTIPLESPINDLEMACHINE,HOWEVER,THESPINDLEITSELFINDEXESTHUSTHEBARSOFSTOCKARECARRIEDTOTHEVARIOUSENDWORKINGANDSIDEWORKINGTOOLSEACHTOOLOPERATESINONLYONEPOSITION,BUTALLTOOLSOPERATESIMULTANEOUSLYTHEREFORE,FOURTOEIGHTWORKPIECESCANBEMACHINEDATTHESAMETIMEVERTICALTURRETLATHESAVERTICALTURRETLATHEISBASICALLYATURRETLATHETHATHASBEENSTOODONITSHEADSTOCKENDITISDESIGNEDTOPERFORMAVARIETYOFTURNINGOPERATIONSITCONSISTSOFATURRET,AREVOLVINGTABLE,ANDASIDEHEADWITHASQUARETURRETFORHOLDINGADDITIONALTOOLSOPERATIONSPERFORMEDBYANYOFTHETOOLSMOUNTEDONTHETURRETORSIDEHEADCANBECONTROLLEDTHROUGHTHEUSEOFSTOPSMACHININGCENTERSMANYOFTODAY’SMORESOPHISTICATEDLATHESARECALLEDMACHININGCENTERSSINCETHEYARECAPABLEOFPERFORMING,INADDITIONTOTHENORMALTURNINGOPERATIONS,CERTAINMILLINGANDDRILLINGOPERATIONSBASICALLY,AMACHININGCENTERCANBETHOUGHTOFASBEINGACOMBINATIONTURRETLATHEANDMILLINGMACHINEADDITIONALFEATURESARESOMETIMESINCLUDEDBYMANUFACTURERSTOINCREASETHEVERSATILITYOFTHEIRMACHINESNUMERICALCONTROLONEOFTHEMOSTFUNDAMENTALCONCEPTSINTHEAREAOFADVANCEDMANUFACTURINGTECHNOLOGIESISNUMERICALCONTROLNCPRIORTOTHEADVENTOFNC,ALLMACHINETOOLSWEREMANUALLYOPERATEDANDCONTROLLEDAMONGTHEMANYLIMITATIONSASSOCIATEDWITHMANUALCONTROLMACHINETOOLS,PERHAPSNONEISMOREPROMINENTTHANTHELIMITATIONOF
