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1、PROPORTIONAL VALVES-BASIC PRINCIPLESPROPORTIONAL VALVES-BASIC PRINCIPLESCopyrightCopyright Eaton Hydraulics 2000 Eaton Hydraulics 2000Steve Skinner,Eaton Hydraulics,Steve Skinner,Eaton Hydraulics,HavantHavant,UK,UK比例阀基本原理比例阀基本原理BASIC SYSTEMBASIC SYSTEM1)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）、
2、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。ABCDEFHGBASIC SYSTEMBASIC SYSTEM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。BASIC SYSTEMBASIC SYSTEMA three position solenoid valve can:-extend the cylinderBASIC SYSTEMBASIC SYSTEMA three position solenoid valve can:-extend the cy
3、linder-retract the cylinderBASIC SYSTEMBASIC SYSTEMA three position solenoid valve can:-extend the cylinder-retract the cylinder-stop the cylinder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。and in the other position it is switched on but there are no intermediate states.然而众所周知，另一种形式的开关能够用来控制灯
4、泡，调光开关However,another type of switch can be used for controlling a light bulb known as a dimmer switch.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In this case,the switch can be turned to any position between fully off and fully on to vary the brightness of the bulb.In this case,the switch can be turned to a
5、ny position between fully off and fully on to vary the brightness of the bulb.In this case,the switch can be turned to any position between fully off and fully on to vary the brightness of the bulb.In this case,the switch can be turned to any position between fully off and fully on to vary the brigh
6、tness of the bulb.In this case,the switch can be turned to any position between fully off and fully on to vary the brightness of the bulb.In this case,the switch can be turned to any position between fully off and fully on to vary the brightness of the bulb.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。In thi
7、s case,the switch can be turned to any position between fully off and fully on to vary the brightness of the bulb.In this case,the switch can be turned to any position between fully off and fully on to vary the brightness of the bulb.BASIC SYSTEMBASIC SYSTEM2)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
8、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。A proportional directional valve can be thought of as the dimmer switch equivalent of an electrical switch.BASIC SYSTEMBASIC SYSTEM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。So in effect the proportional directional valve is acting as both a directional valve and a
9、flow control valve.SWITCHING SOLENOID VALVESWITCHING SOLENOID VALVE一个传统的电磁阀能够被认为是一个简单的开关阀。A conventional solenoid valve can be thought of as a simple switching valve.它可以被一些只有简单电流通断的开关的电设备来控制It is controlled by some form of electrical device which simply switches the electrical current on or off.SWIT
10、CHING SOLENOID VALVESWITCHING SOLENOID VALVEA conventional solenoid valve can be thought of as a simple switching valve.It is controlled by some form of electrical device which simply switches the electrical current on or off.SWITCHING SOLENOID VALVESWITCHING SOLENOID VALVEA conventional solenoid va
11、lve can be thought of as a simple switching valve.It is controlled by some form of electrical device which simply switches the electrical current on or off.PROPORTIONAL VALVEPROPORTIONAL VALVE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。A proportional directional valve however will be controlled by an electrical dev
12、ice more like a dimmer switch.PROPORTIONAL VALVEPROPORTIONAL VALVE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。By varying the current to either solenoid,the amount of spool movement can be varied and hence the amount of flow through the valve can be controlled.PROPORTIONAL VALVEPROPORTIONAL VALVEBy varyi
13、ng the current to either solenoid,the amount of spool movement can be varied and hence the amount of flow through the valve can be controlled.PROPORTIONAL VALVEPROPORTIONAL VALVEBy varying the current to either solenoid,the amount of spool movement can be varied and hence the amount of flow through
14、the valve can be controlled.PROPORTIONAL VALVEPROPORTIONAL VALVEBy varying the current to either solenoid,the amount of spool movement can be varied and hence the amount of flow through the valve can be controlled.PROPORTIONAL VALVEPROPORTIONAL VALVEBy varying the current to either solenoid,the amou
15、nt of spool movement can be varied and hence the amount of flow through the valve can be controlled.PROPORTIONAL VALVEPROPORTIONAL VALVEBy varying the current to either solenoid,the amount of spool movement can be varied and hence the amount of flow through the valve can be controlled.PROPORTIONAL S
16、OLENOIDPROPORTIONAL SOLENOID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）ABCDFGEPROPORTIONAL SOLENOIDPROPORTIONAL SOLENOIDWhen a voltage is applied to the coil connections,an electrical current will flow t
17、hrough the coil.PROPORTIONAL SOLENOIDPROPORTIONAL SOLENOID1)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In turn,the electrical current creates a magnetic field which is concentrated in the metal frame,pole piece and armature.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。There is however a gap in the magneti
18、c circuit between the pole piece and armature so a force is created which acts to close this gap and complete the magnetic circuit.PROPORTIONAL SOLENOIDPROPORTIONAL SOLENOID1)顶针连接着电磁铁和阀芯，通常移动阀芯压缩弹簧。The push-pin connects the solenoid to the valve spool and normally moves the spool against a spring.2)
19、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force created by the solenoid is determined by the strength of the magnetic field which itself is proportional to the current flowing through the coil.PROPORTIONAL SOLENOIDPROPORTIONAL SOLENOID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。Increasing the coil current will incr
20、ease the solenoid force and hence move the spool a greater amount against the spring.PROPORTIONAL SOLENOIDPROPORTIONAL SOLENOIDIncreasing the coil current will increase the solenoid force and hence move the spool a greater amount against the spring.PROPORTIONAL SOLENOIDPROPORTIONAL SOLENOIDIncreasin
21、g the coil current will increase the solenoid force and hence move the spool a greater amount against the spring.FIFIPROPORTIONAL SOLENOIDPROPORTIONAL SOLENOID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。开关电磁阀阀芯开关电磁阀阀芯开关电磁阀阀芯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。A further difference between a switching sol
22、enoid valve and a proportional valve is in the design of the spool.SSQQSWITCHING SOLENOID SPOOLSWITCHING SOLENOID SPOOL1)对于开关阀，阀芯被设计为当阀得电时，将压降最小化。2)这意味着，控制小流量 阀开口要求非常小并且很困难。Which would mean that to control low flow rates,the amount of spool opening required would be very small and difficult to contr
23、ol.SSQPROPORTIONAL SPOOLPROPORTIONAL SPOOL1)比例阀阀芯具有比较宽的边缘带有槽口的台肩。A proportional valve spool therefore has wider lands with notches cut into the edges.SSQPROPORTIONAL SPOOLPROPORTIONAL SPOOL2)因此尽管通过阀的最大流量被减少了（与开关阀对照）但小流量特别容易控制，阀的开口更有规则。So although the maximum flow through the valve may be reduced(com
24、pared to a switching valve)low flows in particular are more easily controlled and the opening of the valve is more gradual.1)比例阀阀芯具有比较宽的边缘带有槽口的台肩。SSQPROPORTIONAL SPOOLPROPORTIONAL SPOOL依据控制的最大流量，不同的阀芯能被适用于不同形状、大小或阀芯槽口的大小特定的阀Depending upon the maximum flow to be controlled,different spools can be fit
25、ted to a particular valve which have different shape,size or number of spool notches.直动式比例溢流阀直动式比例溢流阀直动式比例溢流阀直动式比例溢流阀1)比例阀也可以被用来控制压力。在此比例电磁铁被用来推动一个锥阀芯通过一个弹簧压缩阀座。电磁力越大，推开锥阀芯离开阀座打开阀的压力要求越大。Proportional valves can also be used to control pressure.In this case a proportional solenoid is used to push a p
26、oppet against a seat via a spring.The greater the solenoid force the greater the pressure required to push the poppet off its seat and open the valve.DIRECT ACTING PROPORTIONAL RELIEF VALVEDIRECT ACTING PROPORTIONAL RELIEF VALVE2)这里提供一个直动式溢流阀功能，但象多数此类阀一样，只能允许一个小流量通过该阀。This provides a direct acting r
27、elief valve function but like most such valves,it is only possible to pass small flow rates through the valve.1)比例阀也可以被用来控制压力。在此比例电磁铁被用来推动一个锥阀芯通过一个弹簧压缩阀座。电磁力越大，推开锥阀芯离开阀座打开阀的压力要求越大。Proportional valves can also be used to control pressure.In this case a proportional solenoid is used to push a poppet a
28、gainst a seat via a spring.The greater the solenoid force the greater the pressure required to push the poppet off its seat and open the valve.两两两两-级比例溢流阀级比例溢流阀级比例溢流阀级比例溢流阀为控制大流量，直动式比例溢流阀能被用来作为一个两级溢流阀（或减压阀）的先导级To control higher flow rates,the proportional direct acting relief valve can be used as th
29、e pilot stage of a two-stage relief(or reducing valve).TWO-STAGE PROPORTIONAL RELIEF VALVETWO-STAGE PROPORTIONAL RELIEF VALVETo control higher flow rates,the proportional direct acting relief valve can be used as the pilot stage of a two-stage relief(or reducing valve).BENEFITS OF PROPORTIONAL SYSTE
30、MSBENEFITS OF PROPORTIONAL SYSTEMS比例系统的优点比例系统的优点比例系统的优点比例系统的优点远程控制远程控制远程控制远程控制 传统系统传统系统传统系统传统系统在常规系统中为了调整执行器的速度，流量控制阀必须安装在一个方便的或便于接近的位置，这意味着与操纵台连接的液压管路经常运行在高压下。远程控制远程控制远程控制远程控制 比例系统比例系统比例系统比例系统对于比例系统，控制阀为电子调节，仅需要低功率的电缆连接操纵台和比例阀即可。With a proportional system however,where control valve adjustment is e
31、lectronic,only low-power electrical cables need to be connected between the operators desk and the valve.PLC PLC 远程控制远程控制远程控制远程控制 比例系统比例系统比例系统比例系统今天更多的是，机械控制被数字电子控制所取代，这里情况也是一样，比例阀的电子控制能力为液压系统和电子控制器之间提供一个简单的接口。比例压力控制比例压力控制比例压力控制比例压力控制使用比例方向和压力控制阀意味着机器的所有液压功能（运动和力）能被电子地控制。电磁阀的反应时间电磁阀的反应时间电磁阀的反应时间电磁阀的
32、反应时间 SOLENOID VALVE RESPONSE TIMESOLENOID VALVE RESPONSE TIMEA further benefit of proportional valves is the ability to electronically control the speed of operation of the valve.比例阀地进一步功能是电子控制阀操作速度的能力。0.015SSOLENOID VALVE RESPONSE TIMESOLENOID VALVE RESPONSE TIMEDepending upon its size and voltage
33、supply,a conventional switching solenoid valve will have an energisation response time of approximately 15 milli-seconds.依据阀的大小和提供的电压，一个传统的开关电磁阀对于一个得电动作的反应时间是15毫秒。0.040SSOLENOID VALVE RESPONSE TIMESOLENOID VALVE RESPONSE TIMEThe de-energisation response time will be only slightly slower(typically ar
34、ound 25 ms)since the return spring produces less force than the solenoid.由于回程弹簧的力小于电磁铁，断电的反应时间稍慢（通常25ms左右），S比例阀的反应时间比例阀的反应时间比例阀的反应时间比例阀的反应时间 PROPORTIONAL VALVE RESPONSE TIMEPROPORTIONAL VALVE RESPONSE TIME比例阀阀芯的运动速度能被阀电磁铁的供给电子信号确定。通过逐渐地增加或降低信号（叫做斜坡）可以完成几秒的得电和断电时间。The speed ofmovement of a proportion
35、al valve spool however can be determined by the electronic signal fed to the valve solenoid.By gradually increasing or decreasing the the signal(known as ramping),it is possible to achieve energisation and de-energisation response times of several seconds.1.000SPROPORTIONAL VALVE RESPONSE TIMEPROPOR
36、TIONAL VALVE RESPONSE TIME比例阀阀芯的运动速度能被阀电磁铁的供给电子信号确定。通过逐渐地增加或降低信号（叫做斜坡）可以完成几秒的得电和断电时间。2.000 SPROPORTIONAL VALVE RESPONSE TIMEPROPORTIONAL VALVE RESPONSE TIME比例阀阀芯的运动速度能被阀电磁铁的供给电子信号确定。通过逐渐地增加或降低信号（叫做斜坡）可以完成几秒的得电和断电时间。3.000SPROPORTIONAL VALVE RESPONSE TIMEPROPORTIONAL VALVE RESPONSE TIME比例阀阀芯的运动速度能被阀电磁
37、铁的供给电子信号确定。通过逐渐地增加或降低信号（叫做斜坡）可以完成几秒的得电和断电时间。顶升举例顶升举例顶升举例顶升举例-传统系统传统系统传统系统传统系统 LIFT EXAMPLE-CONVENTIONAL SYSTEMLIFT EXAMPLE-CONVENTIONAL SYSTEM为什么控制阀的阀芯运动速度是用用处的原因是减少系统中的震动，这可以通过控制执行器的加速和减速来完成。假设举例，一个简单的液压系统被用于宾馆中的乘客电梯操作，比较容易说明。顶升举例顶升举例顶升举例顶升举例-传统系统传统系统传统系统传统系统 LIFT EXAMPLE-CONVENTIONAL SYSTEMLIFT EX
38、AMPLE-CONVENTIONAL SYSTEM.当这磁阀得电降低电梯时，阀芯将快速运动，这意味着油缸将极快地加速到其最大速度（最大速度由控制阀F的设置确定），这个突然的启动会给电梯乘客一个极不舒服的感受。F顶升举例顶升举例顶升举例顶升举例-传统系统传统系统传统系统传统系统 LIFT EXAMPLE-CONVENTIONAL SYSTEMLIFT EXAMPLE-CONVENTIONAL SYSTEM同样地,当电梯达到终点时，电磁阀将非常快地关闭产生一个突然地 停止，当然又是一个极不舒服地动作。在一个真正地液压系统中，由于执行器突然起停而产生地震动会产生一个高的尖峰压力，从原理上来说这将导致
39、液压泄漏。顶升举例顶升举例顶升举例顶升举例-比例系统比例系统比例系统比例系统PROPORTIONAL SYSTEMPROPORTIONAL SYSTEM如果电磁阀和流量控制阀被一个比例阀取代，不仅电梯的速度可以被电子地调整，而且电梯的起停也可以被控制。顶升举例顶升举例顶升举例顶升举例-比例系统比例系统比例系统比例系统LIFT EXAMPLE-PROPORTIONAL SYSTEMLIFT EXAMPLE-PROPORTIONAL SYSTEM比例阀能够足够慢地打开以提供一个平滑加速度使电梯达到最大速度。The proportional valve can be opened sufficien
40、tly slowly to provide a smooth acceleration of the lift up to its maximum speed.顶升举例顶升举例顶升举例顶升举例-比例系统比例系统比例系统比例系统LIFT EXAMPLE-PROPORTIONAL SYSTEMLIFT EXAMPLE-PROPORTIONAL SYSTEM同样地，减加速度也能够被控制，使阀芯运动回中位的速度变慢。And likewise the deceleration can be controlled by slowing down the speed of spool movement ba
41、ck to the centre condition.timetimeDistanceDistance运动控制运动控制运动控制运动控制 MOTION CONTROLMOTION CONTROL因此总的来说，比例阀能够提供全部的运动控制包括：In general therefore,proportional valves are capable of providing full motion control in terms of:timetimeAccelerationAccelerationDistanceDistanceMOTION CONTROLMOTION CONTROL1.A sm
42、ooth and controlled acceleration of an actuator up to its maximum speed.一个平滑和受控的加速度，使执行器达到最大速度。timetimeAccelerationAccelerationVelocityVelocityDistanceDistanceMOTION CONTROLMOTION CONTROL2.Control of the actuator velocity and if necessary maintaining it constant with varying loads.执行器速度的控制，如果必要维持其在变
43、化负载下的稳定。timetimeAccelerationAccelerationDecelerationDecelerationVelocityVelocityDistanceDistanceMOTION CONTROLMOTION CONTROL3.A smooth deceleration with minimal pressure peaks.一个平滑的带有最小化压力峰值的减加速度timetimePositionPositionAccelerationAccelerationDecelerationDecelerationVelocityVelocityDistanceDistanceM
44、OTION CONTROLMOTION CONTROL4.By using suitable sensing devices,the proportional valve can also be used to control the actuator stopping position to high levels of accuracy.通过使用合适的传感装置，比例阀也可以被用来高精度地控制执行器的位置timeForce力控制力控制力控制力控制 FORCE CONTROLFORCE CONTROL比例阀也能够被用来控制执行器力地输出，通过控制应用于执行器上地压强。（例如在压机 中 或 注
45、塑 机 应 用）Proportional valves can also be used to control the force output from an actuator(for example in press or plastic injection moulding applications)by controlling the pressure applied to the actuator.timeForceFORCE CONTROLFORCE CONTROL在这样的实例中，不仅要求控制最大的执行器压力。而且要求控制应用中或运动中的压力等级。In such cases it
46、is often necessary to control not only the maximum actuator pressure but also the rate at which the pressure is applied or removed.timeForceFORCE CONTROLFORCE CONTROLIn fact the machine cycle may consist of a series of ramps and holding periods all of which can be achieved with just the one proporti
47、onal valve.实际上机器工作周期可能由一系列的斜坡和停止阶段组成，所有这些可以由一个比例阀来完成。timeForceFORCE CONTROLFORCE CONTROLAt the end of the machine cycle the rate at which the pressure is reduced is also critical in many processes.在机器运行周期后段，在很多工序中压力等级的降低也是要求很严格的。FORCE CONTROLFORCE CONTROLMotion and force control can thus be achieved
48、 using proportional valves,and in some cases the same valve can be used for both motion and force control.This is usually referred to as PQ control ie.the control of both pressure(P)and flow(Q).Furthermore,all of these control functions can be achieved using electronic inputs to the valve thus provi
49、ding a simple interface to the machine controller.运动和力的控制因此能够通过使用比例阀来完成，同时在某些场合同一个阀能够同时用于运动控制和力控制。这通常被称为PQ”控制，也就是说同时控制压力和流量。此外，所有这些控制功能可以使用输入到阀的电子输入信号被完成，只需通过提供的到机械控制器的简单接口。ELECTRONIC CONTROLELECTRONIC CONTROL电子控制电子控制电子控制电子控制阀输入信号阀输入信号阀输入信号阀输入信号 VALVE INPUT SIGNAL VALVE INPUT SIGNAL As described ear
50、lier,the electrical current to the solenoid of a proportional valve needs to be regulated and not just simply switched on or off as is the case with a conventional valve.作为简单描述，提供给比例阀电磁铁的电流需要被调节，不象应用常规阀的时仅有开关通或断那样简单。阀输入信号阀输入信号阀输入信号阀输入信号 VALVE INPUT SIGNAL VALVE INPUT SIGNAL In theory,this could be a