外文翻译--研究利用差动齿轮系实现机械混合压力.doc -- 5 元

ScienceinChinaSeriesETechnologicalSciences©2007ScienceinChinaPressSpringerVerlagStudyofutilizingdifferentialgeartraintoachievehybridmechanismofmechanicalpressHEYuPeng1†,ZHAOShengDun2,ZOUJun2ZHANGZhiYuan21SchoolofMechanicalEngineering,NanjingUniversityofScienceTechnology,Nanjing210094,China2SchoolofMechanicalEngineering,XianJiaotongUniversity,Xian710049,ChinaTheproblemsofhybridinputofmechanicalpressarestudiedinthispaper,withdifferentialgeartrainastransmissionmechanism.Itisproposedthatadjustablespeedamplitudeordifferentialspeedratioistheimportantparametersforthehybridinputmechanism.Itnotonlydefinestheamplitudeoftheadjustablespeed,butalsodeterminestheratioofthepoweroftheservomotortothepoweroftheconventionalmotor.Thecalculatingequationsoftheratiooftransmissioninallaxes,thepoweroftwomotors,andtheworkingloaddistributionarededuced.Thetwokindsofdrivingschemesareputforwardthattheservomotorandtheconventionalmotorsimultaneouslydriveandtheservomotorandtheconventionalmotorseparatelydrive.Thecalculatingresultsdemonstratethatthelatterschemecanusemuchlowerpoweroftheservomotor,sothisschememakesmanufactureandusecostmuchlower.Thelatterschemeproposesafeasiblewaytoapplythehybridmechanismofmechanicalpressinpracticeengineering.mechanicalpress,hybridmechanism,differentialgeartrain,adjustablespeed1IntroductionAtpresenttherearemanyresearchpapersaboutthehybridmechanismofmechanicalpress,andithasbecomeahotresearchtopic.Thehybridmechanismisamechanismwith2degreeoffreedomalsocalleddifferentialspeedmechanism,andwhentwoindependentmotionsareinputatthesametime,theoutputthatcansatisfysomemotionrequirementsisobtainedthroughthemotioncompositionofthemechanism.Thehybridmechanismisalsocalledcontrollablemechanism,orhybridmachine.Thepurposeofresearchonhybridmechanismofmechanicalpressisusingconventionalmotorwithbigpowercarryingflywheeltofinishstampingworkpiecesandusesservomotorwithlowpowertoadjustthesliderspeed.Theadvantagesofthehybridmechanismappliedinthemechanicalpressarethatitnotonlycanreducemuchlowermanufacturingcostthanservopress,butalsohasaflexibleworkingvelocityofslider1.Sothemechanicalpressofhybridmechanismarousesmanyresearchersinterestinworkingonitandthesestudiesaremainlyfocusedonthemultibarhybridmechanism.DuandGuo1,2havecomprehensivelydiscussedthesevenbarhybridmechanismofmechanicalpress,includingthefeasibleconditionsofcompositionofthelinkagemechanism,theslidermotionanalysis,andthetorqueandpowerdistributionbetweenthetwomotorsaswellastheoptimaldesign.Thetrajectoryplanningbasedonpolynomialinterpolationisalsoinvestigated,andthecomputersimulationshowsthattheresultisindeedattractive.Inaddition,Meng3hasalsoinvestigatedthekinematicalanalysisofthesevenbarmechanism,andtheoptimaldesignhasbeencompletedbasedontheminimumpoweroftheservomotormotor,andMenghasproposedthatthehybridmechanismisaresearchdirectionofthemechanicalpress.Tokuz4firstputforwardofthehybridmechanismandanalyzedthevelocitysynthesisbyusingthedifferentialgeartrain.Hisexperimentconfirmedthefeasibilityofhisconception.Theconceptsoftheadjustablespeedamplitudeanddifferentialspeedratioarenotmentionedintheirworks,andtherelationshipbetweenthevelocityvariationandthepowerofthetwomotorswerenotclearlygiven58.Buttheseconceptsareveryimportantandabsolutelynecessaryforthehybridmechanismtoselectthetwomotorspoweranddeterminetheworkingloaddistributionbetweenconventionalmotorandtheservomotor.Inrefs.13theyusedlinkagemechanismtoimplementthehybridinputofmechanicalpress.Themethodisverycomplexbecausethechangeofthelengthandpositionoftheeachbarinlinkagemechanismwillhaveaneffectonthemotionoftheslideofthemechanicalpress.Sosomeprincipalproblemsareusuallyignoredinresearchhybridmechanismcourse,andtheresearchresultsdonnotalwayscoincidewiththepracticeengineeringconditions911.Thegeardifferentialtrainhastwofreedoms,andtheratiosoftransmissionbetweenarbitrarytwoaxesareaconstant.Inordertosimplifythemechanicalmodelandmaketheproblemsmuchprojected,thedifferentialgeartrainisusedastransmissionmechanismtostudythehybridproblemsofthemechanicalpressinthispaper.Thispaperaddressestherelationshipbetweentheadjustablespeedamplitudeandthepowerofthetwomotors,theworkingloaddistributionbetweenthetwomotors,andputsforwardtwodriveschemesoftheconventionalmotorandtheservomotorsimultaneouslyworking,andtwomotorsseparatelyworking.Withthe200tonmechanicalpressastheengineeringbackground,adrivesystemofthehybridmechanismofthemechanicalpressisdesigned,andthefeasibilityofthetwodriveschemesinmechanicalpressisanalyzed.2TheprincipleofthehybridmechanismTheworkingprincipleofthehybridmechanismofthemechanicalpresswithdifferentialgeartrainisillustratedinFigure1.ThesystemconsistsofconventionalmotoralsocalledACmachinewithconstantspeed,servomotor,reducingunitI,reducingunitII,differentialgeartrain,andcrankslidemechanism.Theoutputaxisofthedifferentialgeartrainisconnectedwiththecrankshaftofthecrankslidemechanism.OneofthetwoinputaxeslinkstheconventionalmotorthroughthereducingunitІtheotherinputaxislinkstheservomotorthroughthereducingunitII.Thereforethemotionofthecrankshaftiscompletelycontrolledbythemotionsoftheconventionalmotorandtheservomotor.ThereducingunitІandthereducingunitIIarerespectivelyinstalledbetweenthetwomotorsandthedifferentialgearunitinthewayofserialinordertobearapartofreducingvelocitytaskofthealltransmissionsystem,becausetoobigdriveratioofthedifferentialgeartrainwillmakeitsdrivingefficiencydecreased.Theangularvelocityoftheconventionalmotorisconstant,soitspriceischeaper.Theangularvelocityoftheservomotorisadjustable,soitspriceisexpensive.Inthesystemofthehybridmechanismtheconstantspeedoftheoutputaxisisprovidedbyhighpowerconventionalmotorandtheservomotorprovidesitsadjustablespeed.Therefore,inthisway,itnotonlymakestheoutputmotionofthecrankshaftofthemechanicalpressflexible,butalsoavoidsusinghighpowerservomotor.Henceitcouldsaveboththemachinemanufacturingcostsandthemachineoperatingcosts.Figure1Workingprincipleofhybridmechanismofdifferentialgeartrain.3ThevelocitycharacteristicsofthemechanicalpressslideTheworkofthemechanicalpresspresentstheregularityoftheperiodicchange12.ThedisplacementandvelocitychangesofthemechanicalpressslideinanidealworkcirculationareillustratedintheFigure2.Theslidestartstomovefromtopdeadcentertotheworkingstartpointathighvelocitycalledquickfeedingstage.Whentheslideofmechanicalpressapproachestheworkingpoint,itshighvelocityisshiftedtoslowvelocityandthenitbeginstostampworkpieceatlowvelocitycalledlowworkingstage.Thelowvelocityoftheslideistoavoidgreatimpactonthedie,andbenefittheplasticshapingoftheworkpiece.Aftertheslidefinishesthestampingworkandreachesthebottomdeadcenter,theslidecomesbackathighvelocityandstopsatthetopdeadcentercalledquickbackstage.Hence,themotionvelocityofthemechanicalpressslidecanbedividedthreekindshighdownvelocityV1,slowworkingvelocityV2,andhighbackvelocityV3.ThevelocityV1andvelocityV3shouldbeaspossibleashighandthevelocityV2shouldbeslowandflexibleinordertoensurehighworkingtimesofthemechanicalpressperminuteandsatisfytherequirementsofdifferenttechnologies.Actuallythemechanicalpressonlyworksinaveryshortcoursebeforethebottomdeadcenter,andintheothercoursesitdoesnotdoworktotheworkpiece.4Thenomenclaturesandequationsofthehybridmechanism4.1TherelationshipoftheangularvelocityinallaxesTherearethreeexternalaxesinthedifferentialgeartrainasillustratedinFigure1.Inordertoconvenientlyexpresstherelationshipofthethreeaxes,theaxisconnectedwiththeconventionalmotoriscalledaxis1,theaxisconnectedwithservomotoriscalledaxis2,andtheaxisconnectedwithcrankshaftiscalledaxis0.Theangularvelocitiesofthethreeaxesarerespectivelyexpressedasn1,n2andn0.ThetorquesofthethreeaxesarerespectivelyexpressedasM1,M2andM0.Becausetherearetwofreedomsinthedifferentialgeartrain,onlythethirdaxisisfixed,suchthatthedriveratiooftheothertwoaxescanbedetermined.Sotherelationshipsofdriveratioandangularvelocityofthethreeaxesneedtobeexpressedasthecharacterwithsuperscriptandsubscript.Figure2Idealdisplacementcureoftheslide.4.1.1Theconventionalmotorsinfluenceontheoutputmotion.Whentheservomotorstops,n20,onlytheangularvelocityoftheconventionalmotoraffectstheoutputangularvelocityn0.4.1.2Theservomotorsinfluenceontheoutputmotion.Whentheconventionalmotorstops,n10,onlytheangularvelocityoftheservomotoraffectstheoutputangularvelocityn0,where1n0representsaxis0angularvelocity,and1i20representstotaldriveratiofromaxis2toaxis0includingdifferentialgeartrainandreducingunitIIwhenaxis1servomotoraxisisfixed.4.1.3Theconventionalmotorsandservomotorsinfluenceontheoutputmotion.Whentheconventionalmotorandtheservomotorrunatthesametimethroughthecompositionofthedifferentialgeartrain,theoutputvelocitycanbeexpressedas.Becausetheservomotorcanrunatarbitraryangularvelocitybetweenthezeroandspecificvelocityinbothpositiveandnegativedirections,n2canbeexpressedas.whereKistheratiooftheactualangularvelocitytothespecificangularvelocityoftheservomotorthevalueisarbitrarybetween−1and1,includingzero.n2eisthespecificangularvelocityoftheservomotor.4.2Adjustablespeedamplitudeanddifferentialspeedratio4.2.1Adjustablespeedamplitude.Inordertocorrectlydenotethevariablevelocityofthedifferentialgeartrainofthehybridmechanism,theconceptofadjustablespeedamplitudeisintroduced.AsshowninFigure1,adjustablespeedamplitudeistheratioorpercentageofabsolutevalueofupanddownadjustableamounttothebasespeed.Inthedifferentialgeartrainofthehybridmechanism,theadjustablespeedamplitudeequalstheratiovalueofaxis0outputspeedofoperatingasingleservomotoratthespecificspeedtoaxis0outputspeedofoperatingasingleconventionalmotor13.Inthedifferentialgeartrainofthehybridmechanism,theadjustablespeedamplitudeisthemostbasicandthemostimportanttechnologyparameter.Itnotonlydeterminesthematchingrelationshipofthespeedofthetwoinputaxes,butalsodecidesthematchingrelationshipoftheinstalledcapacityoftheservomotorandtheconventionalmotor