,PROPORTIONAL VALVES - BASIC PRINCIPLES,Copyright Eaton Hydraulics 2000,Steve Skinner, Eaton Hydraulics, Havant, UK,比例阀基本原理,BASIC SYSTEM,1) 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。,A,B,C,D,E,F,H,G,BASIC 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 SYSTEM,A three position solenoid valve can: - extend the cylinder,BASIC SYSTEM,A three position solenoid valve can: - extend the cylinder - retract the cylinder,BASIC SYSTEM,A 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 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 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 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 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.,BASIC SYSTEM,2) 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。 A proportional directional valve can be thought of as the dimmer switch equivalent of an electrical switch.,BASIC 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 flow control valve.,SWITCHING 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.,SWITCHING SOLENOID VALVE,A 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 VALVE,A 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 device more like a dimmer switch.,PROPORTIONAL 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 VALVE,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 VALVE,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 VALVE,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 VALVE,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 VALVE,By varying the current to either solenoid, the amount of spool movement can be varied and hence th