機械原理英文版5齒輪課件

Geartrains reviewn1=-n3=120rpmnH=600rpmDeterminenHDifferentialsDirectionofrotation

Geartrains reGeartrains DifferentialaddingmachineDifferentialsAdifferentialisadevicethatallowsadifferenceinvelocitybetweenintwoelementsGeartrains DGeartrains differentialsDrivingpowerformZ5z1andz3rotateuniformlyb)Ifresistanceismetinz1z3willbefasterthanz1Geartrains dGeartrains DifferentialsGeartrains DGeartrains DifferentialGeartrains DGeartrains DifferentialsGeartrains DGeartrains DifferentialsConstructiondifferentialsGeartrains DGeartrains powertainCase1:A=1（離合器工作）,B=0nHdirectlyoutput=?n3=0Case2:A=0,B=1n3≠0,n3Arminputn4=n1isgivenn4=n1Geartrains poGeartrains powertrainGeartrains poGeartrains powertain3-speedautomobiletransmission1st:z5,z6meshingz3,z4separationA,Bseparation2nd:z3,z4meshingz5,z6separationA,Bseparation3th:A,Bmeshingz3,z4separationz5,z6separation4thBackz6,z8meshingA,Bseparationz3,z4separationz5,z6separation

PowerinoutputTransmissioninautomobileBetterchoicethatspurgearsareusedinthecaseGeartrains poGeartrains powertrainGeartrains pGeartrains powertrain1’8’Consider:Speedratiointhefirstcaseandthesecondcase?Geartrains pCamDesign GearsinmachinetoolPowertransmissionsysteminmachinetoolCamDesign GearsinmCamDesign GearsinmachinetoolSpeedratiodiagramofpowertransmissionsysteminmachinetoolCamDesign GearsinmCamDesign GearsinmachinetoolCamDesign GearsinmGeartrains APPLICATIONSGeartrains APCamDesign EfficiencyThegeneraldefinitionofefficiencyisη=outputpower/inputpower

Efficiencyofaconventionalgeartrainisveryhigh.powerlosspergearset1~2%1)theexternalgearset；η=

0.982)Anexternal-internalgearset:η=

0.993）twostagesgearsetη=η1*η24)Lossestimation

EfficiencyofgeartrainsForepicyclictrains,theefficiencyisdependentondesignfisthefrictioncoefficient5)Helicalgearsetη=96~98%,crosshelicalgearsetη=50~90%

CamDesign EffiCamDesign efficiencyEfficiencyofepicyclegearTorquesbalanceT1+T2+TH=02)Powerin=poweroutfromshaft1toshaft2（β=+1）

E0T1(ω1-ωH

)+T2(ω

2-ωH

)=0

Obtainthetorquesratiothrough(1)(2)CamDesign effCamDesign efficiencyLetgear2isfixed,ω2=0,thefromgear1toarmHTheefficiencyisthat

becauseandthereforeSeecase5CamDesign effCamDesign efficiencyb)fromARMtoshaft1（β=-1）

Ifω2=0thegear2isfixed，powerfromHto1BecauseSeethecase6CamDesign effCamDesign efficiencyDeterminetheefficiencyformgear2toarmBecauseω1=0thereforeρ<1β=-1case7CamDesign effCamDesign efficiencyβ=+1Efficiencyfromgear1toarmβ=-1ρCamDesign effCamDesign efficiency12HZ1=99,Zg=25,Zg’=25,z2=100E0=0.98DeterminetheoverallefficiencysolutionηH1β=-1CamDesign effCamDesign GeartrainExampleinp.308ConsiderthesameFerguson’sparadoxtrainasthefollowingfigure,whichhasthefollowingtoothnumbersandinitialconditionsSungear#2N2=100Sungear#3N3=99Sungear#4N4=101PlanetgearN5=20Inputtosungear#20prmInputtoarm100prmcounterclockwiseCamDesign GeaCamDesign GeartrainCamDesign GeaCamDesign Geartrain-.

ω2=0solution=CamDesign GeaCamDesign Geartrain4SOLUTIONTwoteethdifference,butoutputwillbigdifferenceCamDesign GeaCamDesign HOMEWORKGivez1=z3=17,z2=z4=39,z5=18,z7=152,n1=1450rpmAisloosing,Bisbraking(switchon)DeterminerotationspeednH2)Given1=3549rpm,Z1=36,z2=60,z3=23,z4=49Z4’=69,z5=31,z6=131,z7=94,z8=36,z9=167DetermineoutputspeednHCamDesign HOMEWOCamDesign HELICALGEAR3)WritecalculationvelocityformulaintheepicycletraininFigure9-35(l-k)CamDesign HELICALGeartrains homework3-speedautomobiletransmission1st:z5,z6meshingz3,z4separationA,Bseparation2nd:z3,z4meshingz5,z6separationA,Bseparation3th:A,Bmeshingz3,z4separationz5,z6separation4thBackz6,z8meshingA,Bseparationz3,z4separationz5,z6separation

PowerinoutputWriteallspeedratio(1st~4