文献翻译车床1.docx

文献翻译车床1.docx

《文献翻译车床1.docx》由会员分享，可在线阅读，更多相关《文献翻译车床1.docx（10页珍藏版）》请在冰豆网上搜索。

文献翻译车床1

附录

附录1

英文原文

Lathesarewidelyusedinindustrytoproduceallkindsofmachinedparts.Somearegeneralpurposemachines,andothersareusedtoperformhighlyspecializedoperations.

EngineLathes

Enginelathes,ofcourse,aregeneral-purposemachineusedinproductionandmaintenanceshopallovertheworld.Sizesrangefromsmallbenchmodelstohugeheavydutypiecesofequipment.Manyofthelargerlathescomeequippedwithattachmentsnotcommonlyfoundintheordinaryshop,suchasautomaticstopsforthecarriage.

TracerorDuplicatingLathes

Thetracerorduplicatinglatheisdesignedtoproduceirregularlyshapedpartsautomatically.Thebasicoperationofthislatheisasfallows.Atemplateofeitheraflatorthree-dimensionalshapeisplacedinaholder.Aguideorpointerthenmovesalongthisshapeanditsmovementcontrolsthatofthecuttingtool.Theduplicationmayincludeasquareortaperedshoulder,grooves,tapers,andcontours.Worksuchasmotorshafts,spindles,pistons,rods,caraxles,turbineshafts,andavarietyofotherobjectscanbeturnedusingthistypeoflathe.

TurretLathes

Whenmachiningacomplexworkpieceonageneral-purposelathe,agreatdealoftimeisspentchangingandadjustingtheseveraltoolsthatareneededtocompletethework.Oneofthefirstadaptationsoftheenginelathewhichmadeitmoresuitabletomassproductionwastheadditionofmulti-toolturretinplaceofthetailstock.Althoughmostturretshavesixstations,somehaveasmanyaseight.

High-productionturretlathesareverycomplicatedmachineswithawidevarietyofpoweraccessories.Theprincipalfeatureofallturretlathes,however,isthatthetoolscanperformaconsecutiveserialsofoperationsinpropersequence.Oncethetoolshavebeensetandadjusted,littleskillisrequiredtorunoutduplicateparts.

AutomaticScrewMachines

Screwmachinesaresimilarinconstructiontoturretlathes,exceptthattheirheadsaredesignedtoholdandfeedlongbarsofstock.Otherwise,thereislittledifferentbetweenthem.Botharedesignedformultipletooling,andbothhaveadaptationsforidenticalwork.Originally,theturretlathewasdesignedasachuckinglatheformachiningsmallcastings,forgings,andirregularlyshapedworkpieces.

Thefirstscrewmachinesweredesignedtofeedbarstockandwireusedinmakingsmallscrewparts.Today,however,theturretlatheisfrequentlyusedwithacolletattachment,andtheautomaticscrewmachinecanbeequippedwithachucktoholdcastings.

Thesingle-spindleautomaticscrewmachine,asitsnameimplies,machinesworkononlyonebarofstockatatime.Abar16to20feetlongisfedthroughtheheadstockspindleandisheldfirmlybyacollect.Themachiningoperationsaredonebycuttingtoolsmountedontheturretandonthecrossslide.Whenthemachineisinoperation,thespindleandthestockarerotatedatselectedspeedsfordifferentoperations.Ifrequired,rapidreversalofspindledirectionisalsopossible.

Inthesingle-spindleautomaticscrewmachine,aspecificlengthofstockisautomaticallyfedthroughthespindletoamachiningarea.Atthispoint,theturretandcrossslidemoveintopositionandautomaticallyperformwhateveroperationsarerequired.Afterthemachinedpieceiscutoff,stockisagainfedintothemachiningareaandtheentirecycleisrepeated.

Multiple-spindleautomaticscrewmachineshavefromfourtoeightspindleslocatedaroundaspindlecarrier.Longbarsofstock,supportedattherearofthemachine,passthroughthesehollowspindlesandaregrippedbycollets.Withthesinglespindlemachine,theturretindexesaroundthespindle.Whenonetoolontheturretisworking,theothersarenot.Withamultiplespindlemachine,however,thespindleitselfindexes.Thusthebarsofstockarecarriedtothevariousendworkingandsideworkingtools.Eachtooloperatesinonlyoneposition,butalltoolsoperatesimultaneously.Therefore,fourtoeightworkpiecescanbemachinedatthesametime.

VerticalTurretLathes

Averticalturretlatheisbasicallyaturretlathethathasbeenstoodonitsheadstockend.Itisdesignedtoperformavarietyofturningoperations.Itconsistsofaturret,arevolvingtable,andasideheadwithasquareturretforholdingadditionaltools.Operationsperformedbyanyofthetoolsmountedontheturretorsideheadcanbecontrolledthroughtheuseofstops.

RollingContactBearings

Theconcernofamachinedesignerwithballandrollerbearingsisfivefoldasfollows:

（a）lifeinrelationtoload;（b）stiffness,i.e.deflectionsunderload;（c）friction;（d）wear;（e）noise.Formoderateloadsandspeedsthecorrectselectionofastandardbearingonthebasisofloadratingwillbecomeimportantwhereloadsarehigh,althoughthisisusuallyoflessmagnitudethanthatoftheshaftsorothercomponentsassociatedwiththe