電液比例閥基本原理

1、PROPORTIONAL VALVES - BASIC PRINCIPLESCopyright Eaton Hydraulics 2000Steve Skinner, Eaton Hydraulics, Havant, UK比例閥基本原理BASIC SYSTEM1) 一般認(rèn)為一個(gè)簡單的液壓系統(tǒng)由油箱（A）、電動(dòng)機(jī)（B）、泵（C）、溢流閥（D）、過濾器（E）、流量控制閥（F）、方向控制閥（G）、和油缸（H）組成。2) 油缸的運(yùn)動(dòng)是由流量控制閥（確定運(yùn)動(dòng)的速度）和方向控制閥（油缸運(yùn)動(dòng)的方向）控制。ABCDEFHGBASIC SYSTEM當(dāng)電磁閥得電時(shí)，油缸活塞將伸出和回縮,其速度由流量控制閥確定，

2、而電磁閥不具有控制速度的能力。BASIC SYSTEMA three position solenoid valve can:- extend the cylinderBASIC SYSTEMA three position solenoid valve can:- extend the cylinder- retract the cylinderBASIC SYSTEMA three position solenoid valve can:- extend the cylinder- retract the cylinder- stop the cylinder因此電磁閥的動(dòng)作非常象一個(gè)電路

3、中的開關(guān)在此位置燈是關(guān)閉狀態(tài). 在另外一個(gè)位置是開啟狀態(tài)，而沒有中間狀態(tài)。and in the other position it is switched on but there are no intermediate states.然而眾所周知，另一種形式的開關(guān)能夠用來控制燈泡，調(diào)光開關(guān)However, another type of switch can be used for controlling a light bulb known as a dimmer switch.在這個(gè)例子中，這個(gè)開關(guān)能夠被轉(zhuǎn)到全開和全關(guān)的任一位置，來調(diào)整燈泡的亮度In this case, the swi

4、tch 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.In this case, the switch can be turned to any position between fully off and fu

5、lly 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 brightness of the bulb.In this case, th

6、e switch can be turned to any position between fully off and fully on to vary the brightness of the bulb.在這個(gè)例子中，這個(gè)開關(guān)能夠被轉(zhuǎn)到全開和全關(guān)的任一位置，來調(diào)整燈泡的亮度。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

7、 to any position between fully off and fully on to vary the brightness of the bulb.BASIC SYSTEM2) 閥芯能夠移動(dòng)到在任一位置，而不僅僅是三個(gè)不連續(xù)的位置。閥芯在離開中位的方向仍然確定油缸運(yùn)動(dòng)的方向，但閥芯離開中位的距離控制活塞的速度。1) 比例方向閥能夠被看作與調(diào)光開關(guān)具有同樣功能。A proportional directional valve can be thought of as the dimmer switch equivalent of an electrical switch.BAS

8、IC SYSTEM于是在實(shí)際上比例閥可以同時(shí)作為方向閥和流量閥來使用。So in effect the proportional directional valve is acting as both a directional valve and a flow control valve.SWITCHING SOLENOID VALVE一個(gè)傳統(tǒng)的電磁閥能夠被認(rèn)為是一個(gè)簡單的開關(guān)閥。A conventional solenoid valve can be thought of as a simple switching valve.它可以被一些只有簡單電流通斷的開關(guān)的電設(shè)備來控制It is c

9、ontrolled by some form of electrical device which simply switches the electrical current on or off.SWITCHING 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

10、 off.SWITCHING 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.PROPORTIONAL VALVE一個(gè)比例方向閥是由與一個(gè)與調(diào)光開關(guān)非常象的電設(shè)備控制的。A proportional directional valve however wi

11、ll be controlled by an electrical device more like a dimmer switch.PROPORTIONAL VALVE通過改變兩個(gè)之一電磁鐵的電流，閥芯移動(dòng)的位移能夠被改變，因此控制了通過閥的流量。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 VALVEBy var

12、ying 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 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

13、be controlled.PROPORTIONAL 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 VALVEBy varying the current to either solenoid, the amount of spool movement can be varied and hence the

14、 amount of flow through the valve can be controlled.PROPORTIONAL 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 SOLENOID因此不像傳統(tǒng)的電磁閥，通過比例閥線圈的電流需要被調(diào)整，而不僅僅是開關(guān)式的通斷。比例閥電磁鐵的結(jié)構(gòu)與開關(guān)式電磁鐵是相似

15、的。電磁鐵包括:- 線圈 (A)- 框架 (B)- 電樞 (C)- 電極片 (D)- 頂針 (E)電樞被 包在一個(gè)芯軸管（F）中。 (同時(shí)全部的總成經(jīng)常被壓進(jìn)一個(gè)樹脂塑料的外罩（G）中）ABCDFGEPROPORTIONAL SOLENOIDWhen a voltage is applied to the coil connections, an electrical current will flow through the coil.PROPORTIONAL SOLENOID1) 接下來，電流生成一個(gè)磁場，磁場主要集中在金屬框架、電機(jī)片和電樞中In turn, the electrical

16、 current creates a magnetic field which is concentrated in the metal frame, pole piece and armature.2) 然而在磁回路的電機(jī)片和電樞之間有一個(gè)間隙，于是產(chǎn)生一個(gè)力，其作用是關(guān)閉這個(gè)間隙以完成這個(gè)磁回路。There is however a gap in the magnetic circuit between the pole piece and armature so a force is created which acts to close this gap and complete th

17、e magnetic circuit.PROPORTIONAL SOLENOID1)頂針連接著電磁鐵和閥芯，通常移動(dòng)閥芯壓縮彈簧。 The push-pin connects the solenoid to the valve spool and normally moves the spool against a spring.2) 電磁鐵產(chǎn)生的力The 大小由磁場強(qiáng)度決定，磁場強(qiáng)度與通過線圈的電流成比例force created by the solenoid is determined by the strength of the magnetic field which itself

18、is proportional to the current flowing through the coil.PROPORTIONAL SOLENOID增大線圈電流將加大電磁的力，因此推動(dòng)閥芯壓縮彈簧產(chǎn)生一個(gè)更大的位移。Increasing the coil current will increase the solenoid force and hence move the spool a greater amount against the spring.PROPORTIONAL SOLENOIDIncreasing the coil current will increase the

19、solenoid force and hence move the spool a greater amount against the spring.PROPORTIONAL SOLENOIDIncreasing the coil current will increase the solenoid force and hence move the spool a greater amount against the spring.FIFIPROPORTIONAL SOLENOID電磁鐵被設(shè)計(jì)成電磁力(F)與線圈電流(I)成線性比例關(guān)系。這意味著電磁力僅與線圈電流有關(guān)。開關(guān)電磁閥閥芯開關(guān)電磁

20、閥閥芯比例閥與開關(guān)電磁閥之間的另一個(gè)區(qū)別是閥芯的設(shè)計(jì)。A further difference between a switching solenoid valve and a proportional valve is in the design of the spool. SSQQSWITCHING SOLENOID SPOOL1) 對于開關(guān)閥，閥芯被設(shè)計(jì)為當(dāng)閥得電時(shí)，將壓降最小化。2)這意味著，控制小流量 閥開口要求非常小并且很困難。Which would mean that to control low flow rates, the amount of spool opening r

21、equired would be very small and difficult to control.SSQPROPORTIONAL SPOOL1) 比例閥閥芯具有比較寬的邊緣帶有槽口的臺(tái)肩。A proportional valve spool therefore has wider lands with notches cut into the edges.SSQPROPORTIONAL SPOOL2) 因此盡管通過閥的最大流量被減少了（與開關(guān)閥對照）但小流量特別容易控制，閥的開口更有規(guī)則。So although the maximum flow through the valve ma

22、y be reduced (compared to a switching valve) low flows in particular are more easily controlled and the opening of the valve is more gradual.1) 比例閥閥芯具有比較寬的邊緣帶有槽口的臺(tái)肩。SSQPROPORTIONAL SPOOL依據(jù)控制的最大流量，不同的閥芯能被適用于不同形狀、大小或閥芯槽口的大小特定的閥Depending upon the maximum flow to be controlled, different spools can be f

23、itted to a particular valve which have different shape, size or number of spool notches.直動(dòng)式比例溢流閥直動(dòng)式比例溢流閥1)比例閥也可以被用來控制壓力。在此比例電磁鐵被用來推動(dòng)一個(gè)錐閥芯通過一個(gè)彈簧壓縮閥座。電磁力越大，推開錐閥芯離開閥座打開閥的壓力要求越大。Proportional valves can also be used to control pressure. In this case a proportional solenoid is used to push a poppet agains

24、t 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 VALVE2) 這里提供一個(gè)直動(dòng)式溢流閥功能，但象多數(shù)此類閥一樣，只能允許一個(gè)小流量通過該閥。This provides a direct acting relief valve function but like most such valves, i

25、t is only possible to pass small flow rates through the valve.1)比例閥也可以被用來控制壓力。在此比例電磁鐵被用來推動(dòng)一個(gè)錐閥芯通過一個(gè)彈簧壓縮閥座。電磁力越大，推開錐閥芯離開閥座打開閥的壓力要求越大。Proportional valves can also be used to control pressure. In this case a proportional solenoid is used to push a poppet against a seat via a spring. The greater the sol

26、enoid force the greater the pressure required to push the poppet off its seat and open the valve.兩兩-級比例溢流閥級比例溢流閥為控制大流量，直動(dòng)式比例溢流閥能被用來作為一個(gè)兩級溢流閥（或減壓閥）的先導(dǎo)級To control higher f l o w r a t e s , t h e proportional direct acting relief valve can be used as the pilot stage of a two-stage relief (or reducing

27、valve).TWO-STAGE PROPORTIONAL RELIEF VALVETo control higher f l o w r a t e s , t h e proportional direct acting relief valve can be used as the pilot stage of a two-stage relief (or reducing valve).BENEFITS OF PROPORTIONAL SYSTEMS比例系統(tǒng)的優(yōu)點(diǎn)比例系統(tǒng)的優(yōu)點(diǎn)遠(yuǎn)程控制遠(yuǎn)程控制 傳統(tǒng)系統(tǒng)傳統(tǒng)系統(tǒng)在常規(guī)系統(tǒng)中為了調(diào)整執(zhí)行器的速度，流量控制閥必須安裝在一個(gè)方便的或便于接近的

28、位置，這意味著與操縱臺(tái)連接的液壓管路經(jīng)常運(yùn)行在高壓下。遠(yuǎn)程控制遠(yuǎn)程控制 比例系統(tǒng)比例系統(tǒng)對于比例系統(tǒng)，控制閥為電子調(diào)節(jié)，僅需要低功率的電纜連接操縱臺(tái)和比例閥即可。With a proportional system however, where control valve adjustment is electronic, only low-power electrical cables need to be connected between the operators desk and the valve.PLC 遠(yuǎn)程控制遠(yuǎn)程控制 比例系統(tǒng)比例系統(tǒng)今天更多的是，機(jī)械控制被數(shù)字電子控制所取代

29、，這里情況也是一樣，比例閥的電子控制能力為液壓系統(tǒng)和電子控制器之間提供一個(gè)簡單的接口。比例壓力控制比例壓力控制使用比例方向和壓力控制閥意味著機(jī)器的所有液壓功能（運(yùn)動(dòng)和力）能被電子地控制。電磁閥的反應(yīng)時(shí)間電磁閥的反應(yīng)時(shí)間 SOLENOID VALVE RESPONSE TIMEA further benefit of proportional valves is the ability to electronically control the speed of operation of the valve.比例閥地進(jìn)一步功能是電子控制閥操作速度的能力。0.015SSOLENOID VALVE

30、RESPONSE TIMEDepending upon its size and voltage supply, a conventional switching solenoid valve will have an energisation response time of approximately 15 milli-seconds. 依據(jù)閥的大小和提供的電壓，一個(gè)傳統(tǒng)的開關(guān)電磁閥對于一個(gè)得電動(dòng)作的反應(yīng)時(shí)間是15毫秒。0.040SSOLENOID VALVE RESPONSE TIMEThe de-energisation response time will be only sligh

31、tly slower (typically around 25 ms) since the return spring produces less force than the solenoid . 由于回程彈簧的力小于電磁鐵，斷電的反應(yīng)時(shí)間稍慢（通常25ms左右），S比例閥的反應(yīng)時(shí)間比例閥的反應(yīng)時(shí)間 PROPORTIONAL VALVE RESPONSE TIME比例閥閥芯的運(yùn)動(dòng)速度能被閥電磁鐵的供給電子信號確定。通過逐漸地增加或降低信號（叫做斜坡）可以完成幾秒的得電和斷電時(shí)間。The speed ofmovement of a proportional valve spool howeve

32、r 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 TIME比例閥閥芯的運(yùn)動(dòng)速度能被閥電磁鐵的供給電子信號確

33、定。通過逐漸地增加或降低信號（叫做斜坡）可以完成幾秒的得電和斷電時(shí)間。2.000 SPROPORTIONAL VALVE RESPONSE TIME比例閥閥芯的運(yùn)動(dòng)速度能被閥電磁鐵的供給電子信號確定。通過逐漸地增加或降低信號（叫做斜坡）可以完成幾秒的得電和斷電時(shí)間。3.000SPROPORTIONAL VALVE RESPONSE TIME比例閥閥芯的運(yùn)動(dòng)速度能被閥電磁鐵的供給電子信號確定。通過逐漸地增加或降低信號（叫做斜坡）可以完成幾秒的得電和斷電時(shí)間。頂升舉例頂升舉例-傳統(tǒng)系統(tǒng)傳統(tǒng)系統(tǒng) LIFT EXAMPLE - CONVENTIONAL SYSTEM為什么控制閥的閥芯運(yùn)動(dòng)速度是用用處的

34、原因是減少系統(tǒng)中的震動(dòng)，這可以通過控制執(zhí)行器的加速和減速來完成。假設(shè)舉例，一個(gè)簡單的液壓系統(tǒng)被用于賓館中的乘客電梯操作，比較容易說明。頂升舉例頂升舉例-傳統(tǒng)系統(tǒng)傳統(tǒng)系統(tǒng) LIFT EXAMPLE - CONVENTIONAL SYSTEM.當(dāng)這磁閥得電降低電梯時(shí)，閥芯將快速運(yùn)動(dòng)，這意味著油缸將極快地加速到其最大速度（最大速度由控制閥F的設(shè)置確定），這個(gè)突然的啟動(dòng)會(huì)給電梯乘客一個(gè)極不舒服的感受。F頂升舉例頂升舉例-傳統(tǒng)系統(tǒng)傳統(tǒng)系統(tǒng) LIFT EXAMPLE - CONVENTIONAL SYSTEM同樣地,當(dāng)電梯達(dá)到終點(diǎn)時(shí)，電磁閥將非?？斓仃P(guān)閉產(chǎn)生一個(gè)突然地 停止，當(dāng)然又是一個(gè)極不舒服地動(dòng)作。在

35、一個(gè)真正地液壓系統(tǒng)中，由于執(zhí)行器突然起停而產(chǎn)生地震動(dòng)會(huì)產(chǎn)生一個(gè)高的尖峰壓力，從原理上來說這將導(dǎo)致液壓泄漏。頂升舉例頂升舉例- 比例系統(tǒng)比例系統(tǒng)PROPORTIONAL SYSTEM如果電磁閥和流量控制閥被一個(gè)比例閥取代，不僅電梯的速度可以被電子地調(diào)整，而且電梯的起停也可以被控制。頂升舉例頂升舉例- 比例系統(tǒng)比例系統(tǒng)LIFT EXAMPLE - PROPORTIONAL SYSTEM比例閥能夠足夠慢地打開以提供一個(gè)平滑加速度使電梯達(dá)到最大速度。The proportional valve can be opened sufficiently slowly to provide a smooth

36、acceleration of the lift up to its maximum speed. 頂升舉例頂升舉例- 比例系統(tǒng)比例系統(tǒng)LIFT EXAMPLE - PROPORTIONAL SYSTEM同樣地，減加速度也能夠被控制，使閥芯運(yùn)動(dòng)回中位的速度變慢。And likewise the deceleration can be controlled by slowing down the speed of spool movement back to the centre condition. timeDistance運(yùn)動(dòng)控制運(yùn)動(dòng)控制 MOTION CONTROL因此總的來說，比例閥能夠

37、提供全部的運(yùn)動(dòng)控制包括：In general therefore, proportional valves are capable of providing full motion control in terms of:timeAccelerationDistanceMOTION CONTROL1. A smooth and controlled acceleration of an actuator up to its maximum speed.一個(gè)平滑和受控的加速度，使執(zhí)行器達(dá)到最大速度。timeAccelerationVelocityDistanceMOTION CONTROL2.

38、Control of the actuator velocity and if necessary maintaining it constant with varying loads.執(zhí)行器速度的控制，如果必要維持其在變化負(fù)載下的穩(wěn)定。timeAccelerationDecelerationVelocityDistanceMOTION CONTROL3. A smooth deceleration with minimal pressure peaks.一個(gè)平滑的帶有最小化壓力峰值的減加速度timePositionAccelerationDecelerationVelocityDistanc

39、eMOTION CONTROL4. By using suitable sensing devices, the proportional valve can also be used to control the actuator stopping position to high levels of accuracy.通過使用合適的傳感裝置，比例閥也可以被用來高精度地控制執(zhí)行器的位置timeForce力控制力控制 FORCE CONTROL比例閥也能夠被用來控制執(zhí)行器力地輸出，通過控制應(yīng)用于執(zhí)行器上地壓強(qiáng)。（例如在壓機(jī) 中 或 注 塑 機(jī) 應(yīng) 用 ）Proportional valves

40、can also be used to control the force output from an actuator (for example in press or plastic i n j e c t i o n m o u l d i n g applications) by controlling the pressure applied to the actuator.timeForceFORCE CONTROL在這樣的實(shí)例中，不僅要求控制最大的執(zhí)行器壓力。而且要求控制應(yīng)用中或運(yùn)動(dòng)中的壓力等級。In such cases it is often necessary to co

41、ntrol not o n l y t h e m a x i m u m actuator pressure but also the rate at which the pressure is applied or removed.timeForceFORCE CONTROLIn fact the machine cycle may consist of a series of ramps and holding periods all of which can be achieved w i t h j u s t t h e o n e proportional valve.實(shí)際上機(jī)器

42、工作周期可能由一系列的斜坡和停止階段組成，所有這些可以由一個(gè)比例閥來完成。timeForceFORCE CONTROLA t t h e e n d o f t h e machine cycle the rate at which the pressure is reduced is also critical in many processes. 在機(jī)器運(yùn)行周期后段，在很多工序中壓力等級的降低也是要求很嚴(yán)格的。FORCE CONTROLMotion and force control can thus be achieved using proportional valves, and i

43、n 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 providing a simple interface to

44、 the machine controller. 運(yùn)動(dòng)和力的控制因此能夠通過使用比例閥來完成，同時(shí)在某些場合同一個(gè)閥能夠同時(shí)用于運(yùn)動(dòng)控制和力控制。這通常被稱為PQ”控制，也就是說同時(shí)控制壓力和流量。此外，所有這些控制功能可以使用輸入到閥的電子輸入信號被完成，只需通過提供的到機(jī)械控制器的簡單接口。ELECTRONIC CONTROL電子控制電子控制閥輸入信號閥輸入信號 VALVE INPUT SIGNAL As described earlier, the electrical current to the solenoid of a proportional valve needs to be

45、 regulated and not just simply switched on or off as is the case with a conventional valve.作為簡單描述，提供給比例閥電磁鐵的電流需要被調(diào)節(jié)，不象應(yīng)用常規(guī)閥的時(shí)僅有開關(guān)通或斷那樣簡單。閥輸入信號閥輸入信號 VALVE INPUT SIGNAL In theory, this could be achieved by using a dimmer switch type component (ie. a variable resistor). Practical problems such as heat

46、generation and drift however mean that such a device would not normally be used except for the very simplest applications. 在理論上這可以通過使用一個(gè)調(diào)光開關(guān)式的元件來完成（例如，一個(gè)可變電阻）。實(shí)際上由于發(fā)熱和漂移這樣的設(shè)備一般不被使用，除非一些最簡單的應(yīng)用中。24 V DC比例閥放大器比例閥放大器 PROPORTIONAL VALVE AMPLIFIER Normally, the current flowing through the proportional sol

47、enoid will be controlled by some form of electronic amplifier. The amplifier itself will require a power supply (usually 12 or 24 VDC) and a command input signal.一般地，通過比例閥電磁鐵地電流由一些形式地電子放大器控制。放大器要求一個(gè)電源和一個(gè)命令輸入信號。24 V DC比例閥放大器比例閥放大器 PROPORTIONAL VALVE AMPLIFIER 放大器地輸出（電流）由輸入信號控制，所有零輸入信號，電流輸出也是零。The output of the amplif