力士乐二次调节培训教材中文翻译(部分)

InformationonProjectDesignofSecondaryControlledDrivesIntroduction简介Beforeestablishingrulestobeobservedwhendesigningsecondarycontrolleddrives,Weshouldperhapssummarize,thistimefromadifferentaspect,thebasicdifferencesbetweensecondarycontrolandconventionalhydrostaticdrivetechnology.Fig.230showsthedifferentcharacteristicsofsystemofaprimarycontrolledfixeddisplace-mentmotorandasecondarycontrolledunitatspeedsteppedresponse(Fig.231).Fig.230Systemresponsewithsteppedspeed（阶跃速度响应）2n=speedofsecondaryunitinrpm;p=pressuredifferentialinbar;2Q=flowofsecondaryunitinL/min;2gV=displacementofsecondaryunitincm3;2dM=torqueofsecondaryunitinNm;2P=powerofsecondaryunitinkW.Theconventionaldrivesystemreactstoachangeintorquewithachangeinoper-atingpressuredifferential.Inadditionthereisadirectrelationshipbetweentheswivelangle1（泵排量）oftheprimaryunitandthedrivespeed2n=flowcoupling.在变量泵+定量马达的流量耦联系统中，泵排量1与马达转速2n相关联。Thisrulealsoappliestohydraulicmotorswithvariabledisplacement.Withflowcoupleddrives,speedwillthereforeincreaseasthedisplacementofthehydraulicmotordecreases.上述规则同样适用变量泵+变量马达的流量耦联系统，当流量不变时，马达速度增加意味着马达排量的减小。Fig.231Systemresponsewithsteppedtorque（阶跃扭矩响应）Ifweconvertthisintomathematicalformweobtain➢foraprimarycontrolledfixeddisplacementmotorwithflowcoupling(Fig.232)对于定量马达的流量耦联系统212max~gQnV==马达速度由泵排量决定Withpressurereaction2max2maxmax201[2]glrgnplMMpVtp=++=压力由负载确定Fig.232Primarycontrolledfixedmotor➢foraprimarycontrolledvariabledisplacementmotorwithflowcoupling(Fig.233)变量泵+变量马达的流量耦联系统1222~gQnV==马达速度由泵排量与马达排量比值决定Withpressurereaction2max2max201[2]glrgnplMMpVtp=++=压力由负载确定Fig.233PrimarycontrolledfixedmotorThesecondarycontrolleddrivesystemreactstoachangeintorquewithachangeinflowrequirementi.e.aswithanelectricmotorahighloadingwillresultinalargecurrent.Thereisnolongeradirectrelationshipbetweentheswivelangle1oftheprima-ryunitandthesecondaryspeed2ninthestationarystate.Ifweconvertthisintomathematicalformweobtain➢forasecondarycontrolledunitwithpressurecoupling(Fig.234)22max2222max~2020ggdpVpVM===输出扭矩由二次马达排量决定Withflowreaction222max2max201[2]glrgnlMMVtp=++2222max22maxggQVnVn===流量由二次马达排量和转速Fig.234SecondarycontrolledvariablemotorHowever,inordertocoverasuddenpeakflowrequirement,forexampletobridgethefinalswiveltimeoftheprimaryunit,ahydraulicaccumulatorisusuallyrequired.Thisaccumulatorcanalsobeusedtotakeuppotentialenergyproducedfromlower-ingaloadwithawinchorfromdecelerationofamobilemachine.然而，为适应二次控制系统的流量突变，同时为弥补变量泵的变量响应，通常需要在系统中设置蓄能器。蓄能器还可存储负负载的能量。Typeofcircuit液压回路的类型Withsecondarycontrolledunitsfourquadrantoperationispossibleeveninopencircuits.Thehydraulicaccumulatorsysteminthiscaseisnotsocomplex,asonlyhighpressureaccumulatorsarenecessary.二次元件也可用于开式回路系统，只是需要使用高压蓄能器。Itmust,however,benoted,thatwhenloweringaloadwithwinchorduringdecel-eration,theunitsswitchfrommotortogeneratoroperationi.e.flowdirectionofthefluidisreversed.开式回路中，负负载工况时，二次元件由马达工况变为泵工况，二次元件的油液反向流动。Forthisreason,thepermittedspeedsforopencircuitandpumpoperationmustbeusedasopposedtothoseforclosedcircuitoperation.因此，开式回路许用速度、泵的工作情况与闭式回路不同。Short-termmovementsovercenterandintopumpoperationmustalsobereckonedwithduringhighresponseclosedloopcontroloperation.闭式系统中，必须计算泵工况下的短时超速速度。Whenselectinganopenloopcircuittherefore,itmustbeen-suredthat在开式系统中使用二次元件时，必须满足以下条件：➢themaximumpermissiblespeedinpumpoperationisnotexceeded,泵工况时不允许超速➢thediametersofthesuctionlinearesufficientlylargeand二次元件低压油口（吸油口）管径足够大➢thesuctionportofthesecondaryunitismountedbelowtheoillevel.二次元件低压油口安装位置低于油箱液位Theadvantagesoftheopencircuitarestillmaintainediftheso-calledprefillopera-tion（预压油路系统）iscarriedout.Inthisoperationthesuctionlineispre-filledbymeansofanauxiliarypumpinexceptionalcaseswithaflowofmax1.1fillQQ=atapressureofapprox.15bar.Fig.235showsthebasiccircuitofasecondaryunit(2)inpre-filloperation.Thefillingpump(1),whichcanbecoupledtotheprimaryunit,mustalwaysbeabletogeneratethemaximumflowofthesecondaryunitingeneratoroperation,（低压泵必须满足二次元件在泵工况下的最大流量）anyshort-termpeakrequirementsbeingcoveredbyhydraulicaccumulator(3).Duetothelimitationsshownitisthereforpreferableforsecondarycontrolledop-erationtobeinclosedcircuit.Inthiscase,inadditiontoahighpressureaccumulator,thelowpressurelinemustalsobeequippedwithahydraulicaccumulator.Fig.235Secondaryunitinpre-filloperation（二次元件预压油路系统）Pressurelevel压力等级Apressurelevelof280barbecomestandardintestandsimulationtechnologyasappliedtotheautomobileindustry.Asconstantpressureofupto315bararepermis-siblewiththevalveprogrammetheoperatingpressuremayberaisedtothislevelwithoutproblem.Thisisbecause,withtheexceptionoftheaccelerationphase,theswivelangleisalwayssmallerthan2maxandtheswivelanglehasagreatereffectontheservicelifeofaxialpistonunitsthantheoperatingpressure.通过验证，280bar已称为工程机械行业二次控制液压系统的推荐标准压力。允许在280bar~315bar之间的设定恒压值，原因是二次元件斜盘角取值通常小于最大排量（除开进入加速阶段），斜盘倾角的大小对二次元件的寿命影响，要远大于工作压力的影响。Inordertoproduceahighertorquerequiredforashorttime,withstart-upandbreak-outoflargermomentsofinertiaforexample,theoperatingpressurewithtypeA4VSaxialpistonunitsmayberaisedto400bar,astheservovalveinthisph