ACCESSORY DRIVES - DESCRIPTION AND OPERATION
1. General
A. Accessory drive section consists of inlet gearbox, radial driveshaft, transfer gearbox, horizontal
driveshaft, and accessory gearbox.
B. Power to drive engine and airplane accessories is extracted from accessory drive system.
2. Component Details
A. Inlet Gearbox
(1) High pressure compressor forward shaft transmits power to inlet gearbox. Inlet gearbox then
transmits power through radial driveshaft to transfer gearbox.
B. Radial Driveshaft
(1) Radial driveshaft is mounted within a pressure tube in the No. 7 fan frame strut. Shaft transmits
torque from inlet gearbox to transfer gearbox.
(2) Radial driveshaft is made of steel alloy and is hollow. It measures approximately 20 inches
(508 mm) long and 1.2 inches (30.5 mm) in diameter. Both ends are splined to mate with
transfer and inlet gearbox bevel gears.
C. Transfer Gearbox
(1) Transfer gearbox assembly is bolted to a mount on fan frame aft end at number 7 strut.
Gearbox transmits torque from radial drive shaft to horizontal drive shaft.
(2) Transfer gearbox consists of a main housing, adapters and lower cover, bevel gears, bearings,
and oil jets. Main housing and aft adapter have internal passages and oil jets to provide
lubrication for gears and bearings. Each bevel gear is supported by a ball bearing and roller
bearing. Bevel gear that rotates on vertical axis is splined to the radial drive shaft; bevel gear
that rotates on horizontal axis is splined to horizontal drive shaft.
D. Horizontal Driveshaft
(1) Horizontal driveshaft assembly is mounted between transfer and accessory gearboxes. Its
function is to transmit torque from transfer gearbox to accessory gearbox.
(2) Driveshaft consists of a one piece, machined, tubular steel shaft and an aluminum alloy
housing. Shaft is splined at forward end to transfer gearbox, and at aft end to accessory
gearbox. Forward and aft movement of shaft is limited by an internal flange in transfer gearbox
and by starter output shaft in accessory gearbox. Housing is fitted into gearboxes and held in
position by retaining rings, which fit into grooves at each end of housing. Two additional
grooves in each end of housing are for preformed packings to prevent oil leakage.
E. Accessory Gearbox
(1) Accessory gearbox is installed on bottom of core engine with a mounting rail system, enclosed
in an accessory drive compartment. Gearbox receives torque from the horizontal driveshaft
and distributes torque through spur gears to drive gearbox mounted accessories.
(2) Gearbox assembly consists of a one piece main housing, pad adapters, spur gears, bearings,
seals, and oil nozzles. Pad adapter feature, used to install the gears, bearings, and seals,
permits removal and replacement of these parts without disassembling gearbox. Internal tubes
and oil nozzles provide lubrication of gears and bearings. All gearbox seals are carbon face
rubbing seals which are retained from outside of the gearbox and can be replaced without
disassembly of the gearbox. Gearbox installation system consists of two beams located along
each side of high pressure compressor stator, and a turnbuckle tie rod. Forward ends of
beams attach to hinge mounts on fan frame, aft ends attach to brackets on compressor rear
frame forward flange. Turnbuckle rod attaches to fan frame and gearbox to provide vertical
stabilization and alignment of gearbox.
767
AIRCRAFT MAINTENANCE MANUAL
CF6-80A SERIES ENGINES
72-60-00
NoC
Page 1
D633T1B7 Dec 22/2016
ECCN 9E991 BOEING PROPRIETARY - Copyright © Unpublished Work - See title page for details
EFFECTIVITY
ABX 001-007, 011, 012, 016-019, 021, 022, 025, 101,
109, 114, 115, 314-999
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