Jounalofmatenalsprocesingtechnolgy63(197)81-86ExperimentandstudyintotheaxildriftingofthecylinderofaweldingrolerbedFengangshen,xidepan,jinxueWeldingresarchinstiute,xianjiaotnguniversity.Xian.shanxiprovince71049.P.R.chinaAbstractThebasictheoryoftheaxildriftingofthecylinderofaweldingrolerbedisintroducedinthepaer,andathesametimeexperimntandstudyonthemchanismoftheaxildriftingofthecylinderhavebendoneonaexperimntalmodeloftheweldingrolerbed.Itishownthathemaincauseoftheaxildriftingofthecylinderliesinthexistenceofaspiralnglebetenthecylinderandthecylinderandtheroler.therelativeaxilmotinsbetwentherolerandthecylinderarecompseofspiralmotin,elasticslidingandfrictionalsliding.Thetheoryofcompatiblemotinandno-compatiblemotinisputforwardfortheaxilmotinsofthecylinder.therlativeaxilmotinsofthecylinder.TherlativeaxilmotinbetwentherolersandthecylinderiscordinatedbyelasticslidingandfrictionalslidingbetwenthemKeywords:weldingrolerbed；cylinder；roler；axilmotin；spiralngle1IntroductionInweldingproduction,theasemblyandcirularseamweldingofrotaryworkpiecs,uchasboiler,apetrochemicalpresurevselandson,areconductedon；aeldingrolerbed.WhenrotaingOnaweldingrolerbed.Thecylindewilinevitablyproduceaxildriftingduetomanufacturing,asemblingtoleranceoftheweldingrolerbedandthecylindersurfaceiregularity(divergiufromanidealrotaryorkpiec),thustheweldingproceduremaynotbecariedoutsucesfuly.Itisnecsary,therfore,tostudythemchanismoftheaxildriftingofthecylindertoslvetheproblemoftheaxildriftingofthecylinderincirumferntialwelding.Thersultsofthersearchwilbenfithestudyinganddesignigofantidriftingeldingrolerbed.especialytheanlysioftheapliedforcesonthebed,andleadtodetrminigthemanufacturingandasemblingtoleranceofthebed,andprovidingthebasioftheoryforthemchanicaladjustingmodetoavoidaxildrifting,theadjustingmodeofclosedciruitinthecontrolciruit,andtheslectionftheadjustingvalue.2.Theoreticalanlysi2.1WeldingrolerbedandcylinderAweldingrolerbedisgenralycomposedofourolers.Drivenbythedrivngroler,thecylindermakesarotaryuniformotionarounditsaxis(howninFig.I),duringwhichthecircumferntialweldingprocedureiscariedoutInFig.1,aisthecntralngle,Sisthesuportingdistance,Listhespanoftheroler.andV,isthecircularlinearvelocityofthecylinder,alsonamedtheweldingvelocity2.Theaxisofthecylinderwilbenotparleltothatofaroleriftherolerisdeflctedbyacertainanglefromthedealpositon,orifthecentrsofthefourrolerslieintheverticesofasimplequadrilateral,orifthecentrsofthefourrolersarenotonthesameplane,oriftheciru-larityofthecylinderisiregularbecauseofdeviationinmaufacturingandasembling.Thus.thecylinderwilnevitablymovealongitsaxiswhenrotaingonabedthecontactofthecylinderandarolercanbecansiderdaspointcontactifcytindersaxisandrolersaxisdonotlieinthesameplane.SuposePisthepointofcontact.thecylindersnormalplaneAisdefinedbytheplaneonwhicarethecylindersaxisandgenratrixnacrosthepointoftangencyonthecylinder(showninfig2)makeacylinderstangentplaneBacrospointP.Thus,planeAisverticaltoplaneB.lcisacylinderstangentacrosPandliesinplaneB.IristherolerstangentacrosthesamepointP,andliesinplaneBalso.Ingenral,isdefinedastheaxildeviationanglebetwentherol!ersaxisandthecylindersaxis；isdefinedasthespiralnglebetwengenratrixnandm.aprojectivelineobtainedbyprojectingtherolersgenratrixmacrospointponplaneBandisdefinedastheprojectiveanglebetwennandm,aprojectivelineobtainedbyprojectingmonplaneA.Fig.3indicatesthattherela-tionshipamongstthethreanglesistan=tan2-tan2InFig.3,SB,SandS,arecaledthespiraldisplace-mntvector,theaxildeviationdisplacemntvectorandtheprojectivedisplacemntvectorrespectively.theirrelationshipbeing:Fig.2GeomtricrelationshipbetwenthecylinderandanindivdualrolerFig.3Relationshipbetwentheanglevectorandthedisplacemntvector2.2relativeaxilmotinsrelationship(1)spiralmotin2.Fig.4CompnetofaxilvelocityBecausetherolersaxisisnotparleltothecylin-derscentralline,therisaspiralanglebetwenVr,.andVc,onthepointofcontact(showninFig.2).Whentherolerandcylinderrotaesynchronisticalyaroundtheironaxes,drivenbytangentialfrictionalforce.aspiralefctwilocurbecauseofthediferntlinearvelocitydirectionbetwentherolerandthecylinderatpointPofcontactThecylinderhasacompnetofaxilvelocity,wherVcisthecirularlinearvelocityofthecylinder.isthecylindersaxilcompnetvelociryexrtedbysingleroler,andjcanbe1.2,3,4,represntigthefourrolers,respectively.(2)ElasticslidingBecauseoftheexistenceofaspiralangle,anaxilforceFajactsoncylinder.WhentheforceislesthanthemaximumaxilfrictionalforcefNj(wherfisthefrictionfactor,andNjisthenormalpresurebetwenasinglerolerandthecylinder),thecylinderwilslideelasticalyovertheroleralongtheaxildirection23Thecompnetoftheslidingvelocityis.whereistheelasticslidingfactorformetalicroler.=O.l0.5.(3)FrictionalslidingWhenajisgreatrthanthemaximumfrictionalforcefNj,thecylinderwilmakeafrictionalslidingovertheroler.TheslidingresitanceisfNj3.ThecompnetofthefrictionalslidingvelocityonCylinderisVajthemagnitudeanddirectionofwhiccanbedetrminedbytheuniversalrelationshipbetwenthecylinderandthefourrolersFrictionalslidingwilleadtotheearandtearofthesurfaceofthecylinderandtherolers.whicisunexpectdinweldingproductionWhenthecylinderdrifts,abovethrekindsofmotindonotocursimultaneouslyIherforc.theaxildriftingvelocityofthecylinderisnotthealgebraicsumofthethrecompnetsofvelocityInthecaseofelasticsliding,theaxilvelocityis.2.3axilmotinofthecylinderonaweldingrolerbed2