執(zhí)行器操作原則-中英對照

介紹
本章描述TM-25LP 和TM-200LP 執(zhí)行器的操作。示意圖，圖4-1，說明了各部件之間的工作關(guān)系。

操作
執(zhí)行器由3 個(gè)基本部分組成：
• 一個(gè)力矩電動(dòng)機(jī)伺服閥門
• 彈簧中位四面滑閥
• 帶線性輸出軸的雙面、等面積伺服活塞

TM-25LP 和TM-200LP 執(zhí)行器裝備有力矩電動(dòng)機(jī)伺服閥件。使用一個(gè)雙噴嘴和活動(dòng)擋板產(chǎn)生不同壓力操作第二級(jí)滑閥。力矩電動(dòng)機(jī)從電氣控制裝

置接受直流電信號(hào)，并且把力矩作用于支撐扭轉(zhuǎn)彎曲的單片電樞和活動(dòng)擋板上。伺服閥門將這些活動(dòng)擋板作為流量限制器使用，并且對活動(dòng)擋

板噴嘴兩端的液壓流體進(jìn)行節(jié)流。 兩個(gè)噴嘴通過單獨(dú)固定孔，提供來自執(zhí)行器的液壓流體。 在穩(wěn)態(tài)運(yùn)行期間，活動(dòng)擋板集中在噴嘴中間。為

壓力 Pel和Pc2，兩個(gè)壓力值相等。

當(dāng)輸入電流增加到力矩電動(dòng)機(jī)繞組時(shí)，受限制的(圖解上逆時(shí)針方向)活動(dòng)擋板的活動(dòng)將會(huì)增加，從而限制液壓流動(dòng)到低的噴嘴，而流動(dòng)到上噴

嘴流體將會(huì)增加。結(jié)果是導(dǎo)致滑閥的末端產(chǎn)生了不同的壓力，將滑閥從彈簧中間的零位提高。

在舉升的過程中，滑閥直接對底部伺服活塞提供壓力，同時(shí)，從頂部的入孔對控制部件輸入流體，伺服活塞然后上升，提高執(zhí)行器輸出軸位置

。伺服活塞運(yùn)動(dòng)也給伺服閥門提供位置反饋。

活動(dòng)擋板的擴(kuò)展在反饋彈簧和水平(調(diào)整彈簧)之間進(jìn)行。 提高伺服活塞運(yùn)動(dòng)增加了反饋彈簧力矩，使活動(dòng)擋板再次對準(zhǔn)中心。當(dāng)力矩電動(dòng)機(jī)獲

得力量平衡時(shí)，水平調(diào)整彈簧和反饋彈簧，滑閥重新回到中點(diǎn)，更進(jìn)一步的伺服運(yùn)動(dòng)停住。

執(zhí)行器的降低操作相似�；顒�(dòng)擋板的運(yùn)動(dòng)從上噴嘴限制流體，在提高低的噴嘴的流量時(shí)，這次施加不同的壓力使滑閥降低，并且暴露入口引導(dǎo)

供應(yīng)壓力降低執(zhí)行器輸出位置，再居中行動(dòng)促使伺服活塞運(yùn)動(dòng)壓縮彈簧，活動(dòng)擋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