电液比例阀基本原理课件2010

PROPORTIONALVALVES-BASICPRINCIPLESCopyrightEatonHydraulics2000SteveSkinner,EatonHydraulics,Havant,UK比例阀基本原理BASICSYSTEM1)一般认为一个简单的液压系统由油箱（A）、电动机（B）、泵（C）、溢流阀（D）、过滤器（E）、流量控制阀（F）、方向控制阀（G）、和油缸（H）组成。2)油缸的运动是由流量控制阀（确定运动的速度）和方向控制阀（油缸运动的方向）控制。ABCDEFHGBASICSYSTEM当电磁阀得电时，油缸活塞将伸出和回缩,其速度由流量控制阀确定，而电磁阀不具有控制速度的能力。BASICSYSTEMAthreepositionsolenoidvalvecan:-extendthecylinderBASICSYSTEMAthreepositionsolenoidvalvecan:-extendthecylinder-retractthecylinderBASICSYSTEMAthreepositionsolenoidvalvecan:-extendthecylinder-retractthecylinder-stopthecylinder因此电磁阀的动作非常象一个电路中的开关在此位置灯是关闭状态....在另外一个位置是开启状态，而没有中间状态。andintheotherpositionitisswitchedonbuttherearenointermediatestates.然而众所周知，另一种形式的开关能够用来控制灯泡，调光开关However,anothertypeofswitchcanbeusedforcontrollingalightbulbknownasadimmerswitch.在这个例子中，这个开关能够被转到全开和全关的任一位置，来调整灯泡的亮度Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.在这个例子中，这个开关能够被转到全开和全关的任一位置，来调整灯泡的亮度。Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.Inthiscase,theswitchcanbeturnedtoanypositionbetweenfullyoffandfullyontovarythebrightnessofthebulb.BASICSYSTEM2)阀芯能够移动到在任一位置，而不仅仅是三个不连续的位置。阀芯在离开中位的方向仍然确定油缸运动的方向，但阀芯离开中位的距离控制活塞的速度。1)比例方向阀能够被看作与调光开关具有同样功能。Aproportionaldirectionalvalvecanbethoughtofasthedimmerswitchequivalentofanelectricalswitch.BASICSYSTEM于是在实际上比例阀可以同时作为方向阀和流量阀来使用。Soineffecttheproportionaldirectionalvalveisactingasbothadirectionalvalveandaflowcontrolvalve.SWITCHINGSOLENOIDVALVE一个传统的电磁阀能够被认为是一个简单的开关阀。Aconventionalsolenoidvalvecanbethoughtofasasimpleswitchingvalve.它可以被一些只有简单电流通断的开关的电设备来控制Itiscontrolledbysomeformofelectricaldevicewhichsimplyswitchestheelectricalcurrentonoroff.SWITCHINGSOLENOIDVALVEAconventionalsolenoidvalvecanbethoughtofasasimpleswitchingvalve.Itiscontrolledbysomeformofelectricaldevicewhichsimplyswitchestheelectricalcurrentonoroff.SWITCHINGSOLENOIDVALVEAconventionalsolenoidvalvecanbethoughtofasasimpleswitchingvalve.Itiscontrolledbysomeformofelectricaldevicewhichsimplyswitchestheelectricalcurrentonoroff.PROPORTIONALVALVE一个比例方向阀是由与一个与调光开关非常象的电设备控制的。Aproportionaldirectionalvalvehoweverwillbecontrolledbyanelectricaldevicemorelikeadimmerswitch.PROPORTIONALVALVE通过改变两个之一电磁铁的电流，阀芯移动的位移能够被改变，因此控制了通过阀的流量。Byvaryingthecurrenttoeithersolenoid,theamountofspoolmovementcanbevariedandhencetheamountofflowthroughthevalvecanbecontrolled.PROPORTIONALVALVEByvaryingthecurrenttoeithersolenoid,theamountofspoolmovementcanbevariedandhencetheamountofflowthroughthevalvecanbecontrolled.PROPORTIONALVALVEByvaryingthecurrenttoeithersolenoid,theamountofspoolmovementcanbevariedandhencetheamountofflowthroughthevalvecanbecontrolled.PROPORTIONALVALVEByvaryingthecurrenttoeithersolenoid,theamountofspoolmovementcanbevariedandhencetheamountofflowthroughthevalvecanbecontrolled.PROPORTIONALVALVEByvaryingthecurrenttoeithersolenoid,theamountofspoolmovementcanbevariedandhencetheamountofflowthroughthevalvecanbecontrolled.PROPORTIONALVALVEByvaryingthecurrenttoeithersolenoid,theamountofspoolmovementcanbevariedandhencetheamountofflowthroughthevalvecanbecontrolled.PROPORTIONALSOLENOID因此不像传统的电磁阀，通过比例阀线圈的电流需要被调整，而不仅仅是开关式的通断。比例阀电磁铁的结构与开关式电磁铁是相似的。电磁铁包括:-线圈(A)-框架(B)-电枢(C)-电极片(D)-顶针(E)电枢被包在一个芯轴管（F）中。(同时全部的总成经常被压进一个树脂塑料的外罩（G）中）ABCDFGEPROPORTIONALSOLENOIDWhenavoltageisappliedtothecoilconnections,anelectricalcurrentwillflowthroughthecoil.PROPORTIONALSOLENOID1)接下来，电流生成一个磁场，磁场主要集中在金属框架、电机片和电枢中Inturn,theelectricalcurrentcreatesamagneticfieldwhichisconcentratedinthemetalframe,polepieceandarmature.2)然而在磁回路的电机片和电枢之间有一个间隙，于是产生一个力，其作用是关闭这个间隙以完成这个磁回路。Thereishoweveragapinthemagneticcircuitbetweenthepolepieceandarmaturesoaforceiscreatedwhichactstoclosethisgapandcompletethemagneticcircuit.PROPORTIONALSOLENOID1)顶针连接着电磁铁和阀芯，通常移动阀芯压缩弹簧。Thepush-pinconnectsthesolenoidtothevalvespoolandnormallymovesthespoolagainstaspring.2)电磁铁产生的力The大小由磁场强度决定，磁场强度与通过线圈的电流成比例forcecreatedbythesolenoidisdeterminedbythestrengthofthemagneticfieldwhichitselfisproportionaltothecurrentflowingthroughthecoil.PROPORTIONALSOLENOID增大线圈电流将加大电磁的力，因此推动阀芯压缩弹簧产生一个更大的位移。Increasingthecoilcurrentwillincreasethesolenoidforceandhencemovethespoolagreateramountagainstthespring.PROPORTIONALSOLENOIDIncreasingthecoilcurrentwillincreasethesolenoidforceandhencemovethespoolagreateramountagainstthespring.PROPORTIONALSOLENOIDIncreasingthecoilcurrentwillincreasethesolenoidforceandhencemovethespoolagreateramountagainstthespring.FIFIPROPORTIONALSOLENOID电磁铁被设计成电磁力(F)与线圈电流(I)成线性比例关系。这意味着电磁力仅与线圈电流有关。开关电磁阀阀芯比例阀与开关电磁阀之间的另一个区别是阀芯的设计。Afurtherdifferencebetweenaswitchingsoleno