执行器操作原则-中英对照
介绍
本章描述TM-25LP 和TM-200LP 执行器的操作。示意图，图4-1，说明了各部件之间的工作关系。
操作
执行器由3 个基本部分组成：
• 一个力矩电动机伺服阀门
• 弹簧中位四面滑阀
• 带线性输出轴的双面、等面积伺服活塞
TM-25LP 和TM-200LP 执行器装备有力矩电动机伺服阀件。使用一个双喷嘴和活动挡板产生不同压力操作第二级滑阀。力矩电动机从电气控制装
置接受直流电信号，并且把力矩作用于支撑扭转弯曲的单片电枢和活动挡板上。伺服阀门将这些活动挡板作为流量限制器使用，并且对活动挡
板喷嘴两端的液压流体进行节流。 两个喷嘴通过单独固定孔，提供来自执行器的液压流体。 在稳态运行期间，活动挡板集中在喷嘴中间。为
压力 Pel和Pc2，两个压力值相等。
当输入电流增加到力矩电动机绕组时，受限制的(图解上逆时针方向)活动挡板的活动将会增加，从而限制液压流动到低的喷嘴，而流动到上喷
嘴流体将会增加。结果是导致滑阀的末端产生了不同的压力，将滑阀从弹簧中间的零位提高。
在举升的过程中，滑阀直接对底部伺服活塞提供压力，同时，从顶部的入孔对控制部件输入流体，伺服活塞然后上升，提高执行器输出轴位置
。伺服活塞运动也给伺服阀门提供位置反馈。
活动挡板的扩展在反馈弹簧和水平(调整弹簧)之间进行。 提高伺服活塞运动增加了反馈弹簧力矩，使活动挡板再次对准中心。当力矩电动机获
得力量平衡时，水平调整弹簧和反馈弹簧，滑阀重新回到中点，更进一步的伺服运动停住。
执行器的降低操作相似。活动挡板的运动从上喷嘴限制流体，在提高低的喷嘴的流量时，这次施加不同的压力使滑阀降低，并且暴露入口引导
供应压力降低执行器输出位置，再居中行动促使伺服活塞运动压缩弹簧，活动挡板重新回到中心位置。
Chapter 4. Principles of Operation
Introduction
This chapter describes the operation of TM-25LP and TM-200LP actuators. A schematic drawing, Figure 4-1, illustrates the working relationship of the various parts.
Operation
The actuator consists of three basic sections:
• a torque motor servo-valve
• a spring-centered, four-land spool valve
• a double-sided, equal-area servo piston with a linear output shaft
The TM-25LP and TM-200LP actuators have torque motor servo-valves. They use a double nozzle and flapper to generate a differential pressure to operate the second-stage spool valve. The torque motor received dc current signals from the electric control and applies torque to the single-piece armature and flapper which is supported on a torsion flexure. The servo-valve uses the flapper as a variable flow restrictor and throttles the flow of hydraulic fluid from a nozzle on each side of the flapper. The two nozzles are supplied hydraulic fluid from the actuator supply pressure inlet via separate fixed orifices. During steady state operation, the flapper is centered between the nozzles and the two pressures. Pel and Pc2, are equal.
When input current is increased to the torque motor coil, the limited pivotal movement of the flapper to increase (counterclockwise on the schematic) restricts hydraulic flow from the lower nozzle while flow from the upper nozzle increases. The resulting differential pressure is applied to the ends of the spool valve, raising it from its spring-centered null position.
When raised, the spool valve directs supply pressure to the bottom side of the servo piston and, at the same time, vents the top side to drain at the upper control port, the servo piston then moves up, increasing actuator output shaft position. Servo piston movement also provides position feedback to the servo-valve.
An extension of the flapper is held between the feedback spring and level adjusting spring. Increasing servo piston movement increases the feedback spring torque on the flapper to re-center it. When a force balance is obtained among the torque motor, level adjusting spring, and the feedback spring, the spool valve is re-centered and further servo movement is halted.
Operation of the actuator is similar in the decrease direction. Movement of the flapper restricts flow from the upper nozzle, while increasing flow of the lower nozzle, the pressure differential this time lowers the spool valve and uncovers ports to direct supply pressure to decrease actuator output position, the re-centering action is provided as servo piston movement decreases compression of the lower spring, re-centering the flapper.
2014.9.9