电动车传动设计

TheKinematicDesignofAutomaticGearTransmissionsforBicyclesLong-ChangHsiehandTzu-HsiaChenAbstract-Recently,bicyclesareusedasexercisingmachinesandtrafficvehicles.Planetarygeartrainscanbeusedasthetransmissionsystemsforbicycles.Thepurposeofthisworkistoproposeadesignmethodologyforthekinematicdesignofautomaticgeartransmissionswithplanetarygeartrainsforbicycles.First,applyingthechecklistmethod(combiningandextendingmethods),thedesignconceptsareproposed.Then,basedonthethedesignconceptsproposedandtrainvalueequationofplanetarygeartrain,wederivethegearratioequationsofautomaticthree-speedgeartransmissionsforeachinvention.Threeautomaticthree-speedgeartransmissionsaredesignedtoillustratethedesignmethodology.Basedontheproposedmethodology,allautomaticgeartransmissionswithplanetarygeartrainscanbesynthesized.IndexTerms-Automaticgeartransmissions,chicklistmethod,kinematicdesign,planetarygeartrain.1.IntroductionThebicycleisinventedsofarmorethan200years.Earlybicyclesaremankind'smaintooltorideinsteadofwalk.Inrecentyears,becauseofhavingtheadvantagesoflightweight,cheapandpollution-free,Bicyclesbecomethemostpopulartrafficvehicles.Theycanbeusedasexercisemachinesandtrafficvehicles.Thecharacteristicsofthetransmissionsystemsaretheimportantfactorsforbicycles.Thetransmissionsystemsofthebicyclescanbetheexternalorinternalmulti-speedgearsystems.Theinternalmulti-speedgearsystemisalsocalledasmulti-speedgearhub.Themulti-speedtransmissionsystemofabicycleincludesmulti-speedgearunit,controldeviceofchangingspeed,andoperatingdeviceforsteeringcontroldevicetochangespeed.Figure1showsthemulti-speedtransmissionsystemofabicycle.Planetarygeartrainsarecommonlyusedinvarioustransmissionsduetothereasonofcompactsize,lightweight,andmulti-degreesoffreedom.Ingeneral,ManuscriptreceivedJune24,2008.ThisworkwassupportedinpartbytheNationalScienceoftheRepublicofChinaforforthesupportofthisresearchunderNSC94-2622-E-150-010-CC3.Long-ChangHsiehiswiththePowerMechanicalEngineering,NationalFormosaUniversity,64Wen-HwaRd.,Huwei,Yunlin632,Taiwan.(Correspondingauthor,phone:[phone],fax:[phone],e-mail:[e-mail])Tzu-HsiaCheniswiththeMechanicalandElectro-MechanicalEngineering,NationalFormosaUniversity,64Wen-HwaRd.,Huwei,Yunlin632,Taiwan..(e-mail:[e-mail])Figure1Multi-speedtransmissionsystemofabicycle.planetarygeartrainsusedintransmissionsystemsareplanetarygeartrainwithtwodegreesoffreedomandwithcut-jointincidenttotheframe[1-2].Inthepast,thekinematicanalysisofplanetarygeartrainshasbeenthesubjectofanumberofstudies[3-9].Somestudies[10-20]focusedonthekinematicdesignofautomotivegeardifferentialswithplanetarygeartrains.However,thispaperfocusedonthekinematicdesignofthree-speedgeartransmissionsforelectricassistedbicycles.Byreferringtosuchrelatedpatents[21-29],thestudiesofkinematicanalysisanddesignofplanetarygeartrains[3-20],andthestudiesonconceptualdesignofplanetarygeartrains[30-33],wesynthesizethethree-speedgeartransmissionswithplanetarygeartrainsforelectricassistedbicycles.Thepurposeofthisworkistoproposeasystematicapproachforthekinematicdesignofautomaticgeartransmissionswithplanetarygeartrainsforbicycles.2.PlanetaryGearTrainAplanetarygeartrainisageartraincontainsatleastonegear(planet)whichisrequiredtorotateaboveitsownaxisandanotheraxis.Asimplesungearisasungearifitisadjacenttooneplanetonly,andasimplecarrierisacarrierifitisadjacenttooneplanetonlyorseveralserialplanets.Ifallsungearsandallcarriersaresimplesungearsandsimplecarriers,theplanetarygeartrainiscallednon-coupledplanetarygeartrain;otherwise,itiscalledcoupledplanetarygeartrain.Figures2(a)and2(b)showthenon-coupledplanetarygeartrainandcoupledplanetarygeartrain,respectively.2.1ExistingDesignsTherearemanymulti-speedgeartransmissionsforbicycles.Figure3showsaseven-speedgeartransmissionEngineeringLetters,16:3,EL_16_3_17______________________________________________________________________________________(Advanceonlinepublication:20August2008)whichiscoupledbytwoplanetarygeartrainsanddesignbyMasashiNagano(Shimano)in1991.Figure4alsoshowsaseven-speedgeartransmissionwhichisnon-coupledplanetarygeartrainanddesignbyGunterNurberger(Fichtel&SachsAG)in1993.(a)non-coupled(b)coupledFigure2Planetarygeartrains(a)StructureInputOutputB4B3B2B1C2C1Owc2Owc1(b)SkeltonGearsC1C2B1B2B3B4OWC1OWC21stXXX2ndXXX3rdXXXX4thXX5thXXXX6thXXX7thXXX(c)ClutchsequenceFigure3Self-containedchangespeedapparatusforuseonabicycleandhavingaplanetarygearmechanism(USpatent5,273,500).(a)Structure(b)SkeltonGearsC1C2B1B2B3OWC1OWC21stXXX2ndXXX3rdXXX4thXXX5thXXX6thXXX7thXXX(c)ClutchsequenceFigure4Multi-speeddrivehubwithaseparatemountingringfortheplanetarygearsetforbicycles(USpatent5,399,128).2.2TrainValueEquationForatraincircuitofaplanetarygeartrain,ifitcontainsfirstsungeari,lastsungearj,andcarrierk,therelationshipofωi,ωj,andωkcanbeexpressedas[12-20]:0)()1(−+=−jijjiikjiforξωξωωξ(1a)10)1(−+=jikjijjiiforξωξωξω(1b)jikjiijjiforξωξωωξ−+=1)1((1c)whereξjiisthetrainvalueofsungearjtosungeari.Thetrainvalueξjibepositivesign,ifpositiverotationofωikproducespositiverota