Landing Gear Selector Valve Control Quadrant Assembly Wear Limits 500
32-31-61 Figure 601 (Sheet 1) Nov 15/72
Page 602
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
500 Landing Gear Selector Valve Control Quadrant Assembly Wear Limits
Nov 15/72 Figure 601 (Sheet 2) 32-31-61
Page 603
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
INDEX NO. PART NAME DIM. DESIGN LIMITS WEAR LIMITS REPLACE WORN PART REPAIR WORN PART REPAIR INSTR.
DIAMETER MAX WEAR DIM. MAX DIAM. CLEAR-ANCE
MIN. MAX.
1 BEARING ID 0.9995 1.0000 1.0005 0.0005 X
SHAFT OD 1.0001 1.0004 0.9999 X
2 BEARING ID 0.9995 1.0000 1.0015 0.002 X
SHAFT OF 0.9992 0.9997 0.9985 X
3 SUPPORT ID 1.9997 2.0003 2.0010 0.002 X *[1]
BEARING OD 1.9995 2.0000 1.9990 X
4 SUPPORT ID 1.9988 1.9993 2.0000 0.001 X *[2]
BEARING OD 1.9995 2.0000 1.9990 X
5 CRANK ID 0.005 *[3] X
SHAFT OD X
6 CRANK ID 0.250 0.254 0.261 0.0115 X *[4]
BOLT OD 0.2485 0.2495 0.2475 X
7 VALVE ID 0.250 0.254 0.261 0.0115 X *[4]
BOLT OD 0.2485 0.2495 0.2475 X
*[1] Install 0.060 wall steel bushing in 2.1212 maximum oversize hole. Bushing interference minimum, 0.0013; maximum, 0.0031.
*[2] Install NAS75-4 steel bushing or equivalent in 2.0093 maximum oversize hole. Bushing interference minimum, 0.0013; maximum, 0.0031.
*[3] Spline backlash measured at pitch diameter of spline.
*[4] Install NAS75-4 steel bushing or equivalent in 0.3754 maximum oversize hole. Bushing interference minimum, 0.0002; maximum, 0.0013.
Landing Gear Selector Valve Control Quadrant Assembly Wear Limits 500
32-31-61 Figure 601 (Sheet 3) Nov 15/72
Page 604
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
MAIN GEAR EXTENSION AND RETRACTION - DESCRIPTION AND OPERATION
1. General
A. The main gear extension system raises and lowers the main gear. The main gear retracts or extends simultaneously with the nose gear when the landing gear control handle is moved into the UP or DN detent. The retraction mechanism includes the following components. A main gear actuator applies the force required to raise and lower the gear. The actuator works in conjunction with a walking beam to apply force to the main gear shock strut and swing the gear inboard. Both the actuator and the walking beam are connected to lugs on the shock strut. The outboard ends of the actuator and the walking beam pivot on a beam hanger attached to the airplane structure (Fig. 1). A main gear lock mechanism locks the gear positively in the up or down positions. The lock mechanism is mounted on a reaction link located between the upper ends of the shock strut and side strut. A lock actuator to engage and disengage the uplock is mounted on the side strut end of the reaction link. The gear is locked down by a folding lock strut located between the center of the reaction link and the side strut center hinge. The lock strut is operated by the downlock actuator, mounted on the shock strut end of the reaction link. Spring bungees between the shock strut and lock strut serve to hold the lock strut in either the locked or unlocked positions.
B. Isolation valves are provided for the main landing gear to shut off hydraulic pressure to each main gear. This enables work to be done on the landing gear without depressurizing the hydraulic system. The valves are located in the left wheel well.
2. Main Gear Actuator
A. The main gear actuator converts hydraulic pressure into mechanical power for retraction and extension of the main landing gear. The actuator is a hydraulic piston type, with snubbing action to slow its movement when limits of travel are approached (Fig. 2). The cylinder head end of the actuator is attached to the beam hanger. The piston rod is attached to a lug on the shock strut. The actuator and the walking beam are located in the wing, outboard of the shock strut. Hydraulic fluid is directed to the head end of the actuator through two flexible hoses. Fluid from one hose flows into the cylinder head. A transfer tube built onto the actuator directs fluid from the second hose to the rod end of the cylinder.
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