777 AMM 飞机维护手册 发动机排气 Engine Exhaust PW 777 AIRCRAFT MAINTENANCE MANUAL(35)

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You must remove the strut access panels to get access to the DCV.
DCV Proximity Sensor
The directional control valve (DCV) proximity sensor sends DCV position data to the T/R indicating and fault detection system. The proximity sensor has an electrical connector. The DCV proximity sensor senses the position of the auxiliary slide. When the DCV is in the retract position, the signal from the sensor is target NEAR. When the DCV is in the extend position, the signal from the sensor is target FAR. See section 78-36 for more information.
Functional Description
Control hydraulic pressure from the isolation valve (IV) enters the directional control valve (DCV) through the control pressure port (CONTROL). The control pressure moves the auxiliary slide and main slide against spring force to a mid-mode position in the DCV. This opens internal passages which allows hydraulic pressure from the TRAS pressure port (TRAS PRESS) to move the main slide to the extend position. The main slide connects the TRAS pressure port (TRAS PRESS) to the extend pressure port (EXTEND) and retract (RETRACT) pressure port which go to the hydraulic actuators. The TRAS return port (TRAS RTN) is blocked by the main slide.

EFFECTIVITY BEJ ALL  78-34-00 
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TRAS -DIRECTIONAL CONTROL VALVE

When control pressure from the isolation valve is removed, the auxiliary slide and main slide are pushed back the the retract position by spring force and hydraulic pressure from the TRAS pressure port (TRAS PRESS). The main slide connects the TRAS return port (TRAS RTN) to the extend pressure port (EXTEND) and the TRAS pressure port (TRAS PRESS) to the retract pressure port (RETRACT) that goes to the hydraulic actuators. Hydraulic fluid in the extend line goes to TRAS return port (TRAS RTN).
EFFECTIVITY BEJ ALL  78-34-00 
Page 26 
D633W101-BEJ  May 05/2003 

PW4000 SERIES ENGINES

 

777 AIRCRAFT MAINTENANCE MANUAL

 

TRAS -DIRECTIONAL CONTROL VALVE

EFFECTIVITY BEJ ALL  78-34-00 
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TRAS -HYDRAULIC ACTUATORS, SYNC SHAFTS AND TUBING -INTRODUCTION

General
The sync shafts connect the drive mechanisms of the actuators together. The sync shafts on the left thrust reverser half operate

The thrust reverser actuation system (TRAS) uses six hydraulic independently of sync shafts on the right thrust reverser half.
actuators to extend and retract the thrust reverser sleeves.

The sync shafts make sure the actuators on each sleeve move together.
Hydraulic Actuators

The actuators are linear movement actuators and attach to the torque box and the thrust reverser sleeves. They get hydraulic power from the directional control valve (DCV).
The TRAS uses these two types of actuators:
　
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