液压与气压传动英汉双语 教学课件 作者 陈淑梅第4章Chapter_4.ppt

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1、Chapter4HydraulicActuators4.1HydraulicMotors4.2CylindersThefunctionofhydraulicactuatorsistotranslatehydraulicenergyoffluidintoenergyofthemachine.Theywilldrivethemechanismmotionpathlikeastraight,swingorrotation.Thestraightorswingarereferredashydraulicactuatororswingmotiona

2、ctuator,andtherotationalmotioniscalledhydraulicmotor.Theoutputparametersareforceandspeedortorqueandrotatingspeed.4.1HydraulicMotors4.1.1IntroductionThepopularconceptofahydraulicmotoristhatitisnothingbutapumprunbackwards.1.Characteristicparameters（1）Powerandoverallefficien

3、ciesTheinputpowerofmotoris:(4-1)Theoutputpowerofthemotoris:(4-2)Theoverallefficiencyofthemotoristheratioofto,(4-3)（2）Torquesandmechanicalefficiencies（a）ThetheoretictorqueOralso（b）Startuptorque(4-4)(4-5)（c）Mechanicalefficienciesthus(4-6)(4-7)（3）Flowrateandvolumetricefficie

4、ncy(4-8)(3-9)（4）Deliveryandrotatingspeed(3-10)（5）WorkingandratedpressuresMotorclassificationMotorsmaybeclassifiedbasedupontheirworkingperformances:(1)High-speedhydraulicmotorswhoseratedrotatingspeedisbeyond500r/min;(2)Low-speedhydraulicmotorswhoseratedrotatingspeedisbelow

5、500r/min.High-speedhydraulicmotorsmaybefurtherdividedintogearmotors,vanemotors,axialpistonmotors,screwmotors,etc.Low-speedhydraulicmotorsincludesingle-actingconnectingrodtyperadialpistonmotorsandincurvemultiple-actingradialpistonmotors.Motorscanalsobeclassifiedasfixeddeli

6、veryandvariabledeliveryaccordingtotheirdeliverytypes.Fig.4-1Graphicssymbolsofmotor3.Thegraphicsymbolsofmotor4.1.2Hydraulicmotorsoperation1.AxialpistonmotorsFig.4-2AxialpistonmotorsoperationVanemotorsDouble-actingvanemotorsaregenerallyusedinindustrialhydraulicsystems,herea

7、double-actingdesignoperationisillustratedasfollows:Fig.4-3BalancedvanemotoroperationStructurefeaturesThevanesinavanemotorarepositionedradiallywithazerovaneangle(θ=0).Ashuttlevalveissetatthepathbetweenhigh/lowpressureoilchambersandthevanebottomtoensurehighpressureoilatthev

8、anebottom.Toensureanormalstartup,aspringwithpreloadismountedatthevanebottomtopreventtheconnectio