外文翻译--基于三维设计的浮动式制动卡钳的车床夹具的研制.doc

英文原文Developmentofthe3D-DesignedLatheFixtureofaFloatBrakeCaliperPANJin-kun1,ZUOWan-li2,LUDong-sheng21SchoolofMechanicalEngineering,NanjingInstituteofTechnology,Nanjing211167,P.R.China2CollegeofMechanical&PowerEngineering,NanjingUniversityofTechnology,Nanjing210009,P.R.ChinaAbstract：Accordingtothetechniquerequestsofthebrakecaliperintheprocessofproduction,aspecialfixtureoffloatbrakecaliperhasbeendevelopedbasedon3Ddesigninthispaper.Thedevelopmentprocessandverifieddatafrom3Dmodelingandkinematicssimulationforthisspecialfixtureshowthatthis3D-designedprocesscanconvenientlyforecasttheassemblyinterferenceofthefixtureandaccuratelyaddthemassofleadbrickbeforetheprototypeismade.Inthiswaythefluttercausedbytheunbalancedlathefixturecanbeeliminatedandtheprecisionofrun-outtoleranceincylinderholecomparedwithmachinetoolspindlecanbeimproved,thustheprocessingqualityofthecylinderholeinabrakecalipercanbegreatlyguaranteed.Keywords:3Ddesign；brakecalipers；lathefixture1IntroductionIntheproductionofthefloatdiscbrakecaliperofanautomobile,duetothecomplexityofitsstructure,aspecialfixtureisneededforinstallingandclampingthebrakecaliper.Accordingtothetechniquerequestsofthebrakecaliperintheprocessing,aspecialfixtureoffloatbrakecaliperisdevelopedbasedon3Ddesigninthispaperandits3Dmodelisassembledvirtually.Throughthemechanismsimulationfunctionof3Ddesignsoftware,thebalanceofalathefixtureisanalyzed1.Theresultsshowthatthedesignprocesscanexpedientlyforecastsomefactorswhichaffectthequalityoftechnicalequipmentsuchasassemblyinterference2andthemachiningstabilityofthelathefixturebeforetheprototypeismade.Thisdesignprocesscannotonlyavoidthedesignerrorsinthetraditionaldesign,butalsoimprovethedesignqualityofproducts.23DdesignofthespeciallathefixtureThemanufactureobjectofthespecialfixtureisthebrakecaliperofafloatdiscbrake,shownasFigure1；itsmachiningsurfaceisthecylinderholeofthebrake.Thefigureshows:whenthecylinderholeisbeingprocessed,itsaxisandthemachinespindlerotationaxismustbeincoincidence.Duetoirregularshapestructureofthebrakecaliper,theflutterwhichiscausedbytheunbalancemassposedbythefixtureandtheworkpiecewouldaffectthemachiningaccuracyandroundnessofthecylinderholesizeintheactualprocessing,andsomeprecisionrequirementofgeometrictolerancesuchasparallelismbetweenthetwocylinderholes.Toavoidtheproblemsinthedesignprocessofthelathefixtureofthebrakecaliper,aspecialfixtureisdevelopedbasedon3Ddesigninthispaper.Accordingtotheshapestructuralcharacteristicsofthebrakecaliperandtheclampingrequirementsofthelathefixture,thecylinderholeshouldbecompletedafteraclampingofthelathefixtureinthewholeprocessing.Theflangeneedsthemountingholeofmachinetoolspindleandlocationholeofthefixtureonbothsidesofthecenterasamiddlewareconnectingthemachinetoolspindleandthefixture.Itisensuredthattheaxisoftheprocessingcylinderholeofthecaliperbodywhichislocatedandclampedonthefixtureandthemachinespindleaxisofrotationneedcoincidence3,asshowninFigure2.Themodelingprocessofotherpartsofthespecialfixtureisnotdepictedindetailinthispaper，pleaserefertoReference4.Thenthesepartsareassembledintotwocomponents,upanddown,asshowninFigure3andFigure4.Thewholefixtureisdividedintotwocomponentswhenitisbeingassembled.Thiscanavoidthepartsbeingmissedorinstalledwronglyintheassemblyprocess.Inthecomponentdown,asthebenchmarkofflange,thecounterbalanceisfixedwithbolts.Thecounterbalancewouldberegulatedinbalancewhenthefixtureisproduced.Inthecomponentup,asthebenchmarkofthefixture,thelocatingplateisfixedwithsevenbolts.Thenasthebenchmarkofthelocatingplate,theupperhalfpartoftwothreadedstudsarerotatedintothelocatingplate,andthepressureplateisclampedonthethreadedstudsbybolts.Inthefixture,thepressureplateisindirectcontactwiththeworkpiece,soitisundergreatstress.Therefore,thematerialof45Mn2isselected,whichneedstreatmentofquenchingandtempering.Matchingblockneednottobefixedintothefixtureduringtheinitialassemblyandthemassofmatchingblockisdeterminedbytheresultofmotionsimulation.Figure1BrakecalipersFigure2FlangeFigure3ComponentdownFigure4ComponentupAftertheassembliesofcomponentupandcomponentdownarecompleted,theyarecombinedinanewcomponentunit,withtheboltsandnuts,asshowninFigure5shows.Duetoadoptinghierarchicalassembly5,itisrationalinthepracticalproductionprocessandthepartsmanagementiseasy,whichcaneffectivelyshortenthedesigncycle.Figure5Componentunit13BalanceanalysisofthekinematicsofthespeciallathefixtureThemassofeachpartneedstobedeterminedbeforetheprocessofkinematicssimulationofthespeciallathefixture.AsisshowninFigure6,thematerialanddensityofeachpartisdefinedbymenucommandmechanism/qualityattributes,asTable1shows,thevolumeandmassofpartarecalculatedoutby3Ddesignsoftware.Weselectcarbonsteelasthematerialofotherstandardpartssuchastheboltsandnuts,itsdensityis7.85g/cm3.IntheprocessofdefiningthemassonPro/E,unitconversionalsoneedsattention.Figure6DissectionfigureofthefixtureTable1MaterialanddensityofthemainpartsoffixtureNumberPartnameMaterialDensity(g/cm3)1counterbalanceA37.852flangeHT2007.23fixtureHT2007.24matchingblocklead11.375locating457.856pressureplate45Mn27.85Establishingcomponentunite,andthen,componentunit1wouldbeassembledonthemainshaftasthebenchmarkofmachinespindleaxisbythewayof“connection-pinconnection”,asisshowninFigure7.Afterenteringamechanicmodel,thegravityissetinadefaultvalue.Inthecolumnof“direction”,wesetX:-1,other:0.Addedinamotor,itsrotationrateis360r/min.Thena“run”isestablishedwithitssettings,“dynamictype”and“openinggravity”inthecolumnof“externalload”.Tillthen,thekinematicssimulationprocesscanrun.Inordertoreduceflutterofthecylinderhole,thebalanceofaspecialfixtureistakenasthekeyanalysisinthispaper6,7.Theobjectiveofbalanceanalysisistomaketheholisticcentroidofthefixtureandtheworkpieceinthemachinespindleaxisofrotation.Thus,weshoulddeterminetheholisticcentroidofthefixtureandtheworkpiecefirst.Thenthedistancebetweenholisticandspindleaxiscanbeobtained.Thedistancebetweentheholisticandspindleaxisshouldinclinetozeroasfaraspossiblebyadjustmentofthemassofthematchingblock.ThedetailedlocationsofcentroidsinthreedirectionsofX,Y,ZcanbeobtainedthroughthemeasuringfunctionofPro/E.BecauseofsettingthemachinespindleaxisofrotationastheZaxis,thedistanceofthecentroidrelativetothecentrerotationcanbedeterminedonlyinneedofthemaximumofthecentroidatthedirectionofXorY.ThemeasurementresultsoffixturesimulatedmotionwithoutamatchingblockisshowninFigure8.Whenthefixtureturnedabout90,themaximumdeviationdistanceofthecentroidis22.08mminthedirectionofX.Onlybydoingthatcanweknowthatthecentroidisnotontheaxis；asaresultitdoesnotmeetthebalancerequirement.Figure7Component