翻譯部分英文部分：Thehydraulicactuatoristhehydraulicpumpprovideshydraulicenergyintomechanicalenergyconversiondevice,whichcompriseshydrauliccylindersandhydraulicmotors.Outputrotationalmovementofthehydraulicactuatorisahydraulicmotorhabits,whiletheoutputofthelinearmovement(includingoutputswingmovement)ofthehydraulicactuatorelementisreferredtoasthehydrauliccylinder.AhydraulicmotorcharacteristicsandclassificationThehydraulicpumpandthehydraulicmotorisareversiblehydrauliccomponents,fromtheviewpointofenergyconversioncanbeinputtoanyoneofthehydraulicpumpworkingfluid,itbecomesahydraulicmotorworkingconditions；Conversely,whenthemainshaftofthehydraulicmotorbytheouterthetorquedriventorotate,butalsobecomeshydraulicpumpconditions.Becausetheyhavethesamebasicstructuralelements-sealedandmayperiodicallychangethevolumeandcorrespondingwiththeoilbodies.However,duetodifferentoperatingconditionsofthehydraulicmotorandahydraulicpump,theperformancerequirementsarenotthesame,sotherearestillmanydifferencesbetweenthehydraulicmotorandahydraulicpumpofthesametype.Firsthydraulicmotorshouldbecapableofbeingreversedandthusrequiresthatitsinternalstructuresymmetry；hydraulicmotorspeedrangeneedstobelargeenoughtohavecertainrequirements,inparticularitsminimumsteadyspeed.Therefore,itisusuallytheuseofrollingbearingsorhydrostaticbearings；secondhydraulicmotorduetoanoilundertheconditionsoftheinputpressure,andthusdonotneedtohaveaself-primingability,butneededthecertaininitialsealingperformance,inordertoprovidethenecessarystartingtorque.Duetotheexistenceofthesedifferences,sothatthehydraulicmotorandthehydraulicpumpisrelativelysimilarinstructure,butnotreversible.Hydraulicmotorinaccordancewithknotplumtypecanbedividedintogear,vane,piston,andothertypes.Dividedintohighandlowspeedtwocategoriesaccordingtothehydraulicmotorratedspeed.Higherthantheratedspeed500r/minisahigh-speedhydraulicmotor,ratedspeedlessthan500r/minisalow-speedhydraulicmotor.Thebasictypesofhigh-speedhydraulicmotorgear,screw,vaneandaxialpiston.Theirmaincharacteristicsisthehighspeed,smallmomentofinertia,easystartingandbraking,adjusthighsensitivity(speedandcommutation).Often,speedhydraulicmotoroutputtorque(NmofonlytenstohundredsofNm),itisalsoknownasahigh-speedlowtorquehydraulicmotor.Basictypesoflow-speedhydraulicmotorisaradialpistontype,inadditiontolow-speedaxialpiston,vaneandgearstructuretype,themainfeaturesofthelow-speedhydraulicmotorislargedisplacementvolumelowspeed(sometimesuptoafewturnsperminuteorevenafewtenthsofturn),itcanbedirectlyconnectedwiththeworkingbodiesdonotneedtoslowdownthedevice,thetransmissionmechanismgreatlysimplified,usuallylow-speedhydraulicmotoroutputtorque(uptoseveralthousandNmtensofthousandsNm),itisalsoknownasthelowspeedhightorquehydraulicmotor.Second,thehydraulicmotoroperatingprinciple1VanehydraulicmotorDuetotheroleofpressureoil,theunevenrotortorque.Vanehydraulicmotoroutputtorqueandthedisplacementofthehydraulicmotorandthehydraulicmotorandoutofthepressuredifferentialbetweentheports,itsspeedisdeterminedbythesizeoftheinputflowrateofthehydraulicmotor.Hydraulicmotorsaregenerallyrequiredtoreversingradialvanehydraulicmotorsleavesplaced.InordertomakethebladerootalwaysthroughtheoilpressureinthebackpressurechamberWalterbladerootpathshouldbesettoaone-wayvalve,inordertoensurethatthevanehydraulicmotorinthenormalpressureoilWalter,thetopofthebladeandTheinnersurfaceofthestatorinclosecontactinordertoensureagoodseal,andthereforeshouldbesettothebladeroottothepreloadspring.Vanehydraulicmotorsmallsize,smallmomentofinertia,quickaction,applicabletothecommutationfrequencyishigher,butthelargeamountofleakage,low-speedoperationisunstable.Vanehydraulicmotorsaregenerallyusedforhighspeed,torqueissmallandtheoperationalrequirementsofsensitiveoccasions.2radialpistonhydraulicmotorFigure3-2radialpistonhydraulicmotorschematicwhenpressureoilfixedoildistributionshaft4windowintothebottomofthecylinderinnerplunger1,theplungerextendsoutwardlytightlytopliveintheinnerwallofthestator2andtheeccentricitye,duetothepresenceofthestatorandthecylinderblock.Theplungerincontactwiththestator,thestatorofthereactionforceoftheplunger.Theforcecanbedecomposedintotwocomponents.Whenthefluidpressureactingonthebottomoftheplungerp,plungerdiameterD,theanglebetweentheforceandDuration,theywereandproduceatorqueforceonthecylinder,thecylinderrotation.Cylinderandthenconnectedtothedriveshaftthroughtheendfaceoutwardoutputtorqueandspeed.Theaboveanalysisofatorquegeneratedbytheplungerroleinthepressurechamberthereareseveralplunger,theplungertorquegeneratedbyrotationofthecylinder,andtheoutputtorque.Radialpistonhydraulicmotorisusedforlowspeedandhightorque.3axialpistonmotorAxialpistonpumpvalvewithflow,otherformsofprinciplecanbeusedasahydraulicmotor,axialpistonpumpsandaxialpistonmotorisreversible.Axialpistonmotorworksasshown,withtheoilpanandtheswashplatefixedand5andthecylinderofthemotorshaftconnectedtorotatetogether.Whenthepressureoilthroughtheoilpanwindowintothecylinderplungerhole,theplunger3inthepressureoilundertheoverhang,theplungeragainsttheswashplateswashplate3generatesamethodtothereactionpThisforcecanbedecomposedintoaxialandverticalcomponentwhere.Whereandplungerhydraulicpressurephaseequilibrium,wheretheplungercreatesatorqueonthecenterofthecylinder,drivenbythemotorshaftrotatescounterclockwise.Axialpistonmotorinstantaneoustorquepulsation.Ifyouchangethemotoroilpressureinputdirection,themotorshaft5rotatesclockwise.Theinclinationoftheswashplateisachange,i.e.thechangeofthedisplacement,notonlyaffectsthetorqueofthemotor,butalsoaffectsitsspeedanddirection.Thegreatertheinclinationangleoftheswashplate,thegreaterthetorqueisgenerated,thelowerthespeed.4.GearhydraulicmotorGearmotoronthestructureinordertoadapttoreversingrequirementsoutoftheoilportequaltothesymmetryhaveseparateexternalcasedrainthebearingportionoftheleakageofoilleadstotheoutsideofthehousing；usesrollinginordertoreducethestartfrictiontorque；torqueinordertoreducetheThepulsatinghydraulicgearmotorTeethmorethanthenumberofteethofthepump.Gearhydraulicmotorworsebythedrytightness,Yungrentlessefficientinputpressureisnottoohigh,youcannothaveagreatertorque.Withthechangeofpositionoftheengagementpointandtheinstantaneousspeedandtorquevaries,thehydraulicgearmotorthereforeonlysuitablefortheoccasionofthehighspeedandsmalltorque.Generalwithadryconstructionmachinery,agriculturalmachinery,andmachineryandequipmentlessdemandingtorqueuniformity.1.Thedisplacementofthehydraulicmotor,thedisplacementandtorquerelationshipTheoutputtorqueofthehydraulicmotorworkinginsizeisdeterminedbytheloadtorque.However,topromotethesamesizeoftheload,theworkingcavityofthepressureofthemotorislowerthanthepressureoftheworkingcavitysmallmotor,sothatthesizeoftheworkingcavityisanimportantsymbolofthehydraulicmotorabilitytowork.Representationofthesizeoftheworkingcavityofthehydraulicmotorandthehydraulicpump,whichmeansthatCCV.Thedisplacementofthehydraulicmotorisanimportantparameter.Canbecalculatedatagivenpressure,thesizeofthehydraulicmotorcanoutputtorque,thesizeoftheworkingpressureunderagivenloadtorquemotormayalsobecalculatedaccordingtothesizeoftheCC.Whenthehydraulicmotorintothepressuredifferencebetweentheoiloutletfortheinputofthehydraulicmotorflowrateq,thetheoreticaltorqueofthehydraulicmotoroutput,theangularvelocity,ifnottakingintoaccountthelossofhydraulichydraulicpumpoutputpowershouldbeallconvertedtohydraulicthemechanicalpowerofthemotoroutput,i.e.Because,sothetheoreticaltorqueofthehydraulicmotor2.ThemechanicalefficiencyofthehydraulicmotorandstartthemechanicalefficiencyHydraulicmotorinternalinevitablythepresenceofavarietyoffriction,theactualoutputtorquethanthetheoreticaltorquesmaller,i.e.Wherethemechanicalefficiencyofthehydraulicmotor.Inaddition,underthesamepressure,theoutputtorqueofthehydraulicmotorbeginstoturnfromresttostart-upstatetorquethantheoperatingloadtothehydraulicmotortostartthecausedifficulties,sothestart-upperformanceofthehydraulicmotorisveryimportant.Thestartingtorqueisreducedbecausethemaximumcoefficientoffrictioninastationarystate,appearsonthefrictionsurfacetherelativeslidingcoefficientoffrictionissignificantlyreduced,whichisthegeneralnatureofthemechanicalfriction.Hydraulicmotor,thestationarystatelubricantfilmissqueezedout,basicallybecomesdryfriction.Andthemotorbeginstomove,withtheestablishmentofthelubricantfilm,frictionimmediatelydropandreducedincreaseswiththeslidingvelocityandfilmthickening.Hydraulicmotorstart-upperformanceindicatorsstartmechanicalefficiency,whichwasexpressedaswhereinthestartingtorqueofthehydraulicmotor.Differenttypesofhydraulicmotors,internalforcecomponentsoftheforcebalanceisdifferent,thesizeofthefriction,andsoarenotthesame.Thesametypeofhydraulicmotor,theforceoffrictionpairbalanceddesign,itshighandlowpoints.Forexample,somegear-typehydraulicmotoronlyabout0.6,andthehigh-performancelow-speedhightorquehydraulicmotorcanbeachieved=0.90,varyconsiderably.So,ifthehydraulicmotorloadstart,itmustbenotedthatthestart-upperformanceoftheselectedhydraulicmotor.3.Hydraulicmotorspeedandlow-speedstabilityTherotationalspeedofthehydraulicmotorvarydependingonthedisplacementVoftheliquidsupplyflowrateq,andthehydraulicmotoritself.Sincethehydraulicmotorinternalleakage,notalltheliquidintothemotordrivingthehydraulicmotoracting,asmallportionoftheliquidislostduetoleakagelosses,sotheactualmotorspeedthanIdeallylow.whereinthevolumetricefficiencyofthehydraulicmotor.Inengineeringpractice,thespeedofthehydraulicmotorandhydraulicpumpspeed,measuredinunitsofmulti-purposer/min(r/min).Whentheoperatingspeedofthehydraulicmotoristoolow,oftentomaintainnotuniformspeed,theunstablestateofthedynamicstop,whichiscalledcreepingphenomenon.Requirehigh-speedhydraulicmotordoesnotexceedtheto10r/minlowspeedhightorquehydraulicmotordoesnotexceedspeedworkof3r/min,notallofthehydraulicmotorcanmeettherequirementsof.Generallyspeaking,lowspeed-low-speedtorquehydraulicmotorstabilitythanthehigh-speedmotoraswell.Thelargedisplacementofthelowspeedhightorquemotor,andthusthesizeislarge,andnotcausedbytoolowevenatlowspeedstheslidingspeedofthefrictionpairs,coupledwiththemotordisplacement,theeffect