2) Nozzles are segmented with multiple vanes in each segment. Nozzle segments
have an integral honeycomb interstage seal.
3) Segmented turbine shrouds are of conventional honeycomb design. Shrouds, which
are located axially in line with shrouded turbine rotor blades, provide close tolerance
sealing and also have heat shields to reduce casing wall temperature.
4) A clearance control manifold discharges fan air onto surface of case through an
array of small holes. Cooling air reduces radial clearances of low pressure turbine
rotor improving the low pressure turbine efficiency.
(4) Low Pressure Turbine Rotor
(a) Low pressure turbine rotor drives fan rotor through fan midshaft. Rotor is located between
low pressure turbine forward case and turbine rear frame. Rotor is supported by No. 6
bearing in the C sump.
1) Low pressure turbine rotor consists of four similar turbine disks. They are
assembled by a bolt hole circle in spacer arm flange. Turbine shaft outer flange and
interstage seal race are sandwiched between spacer arms of 2nd and 3rd-stage
disks and bolted together. 1st-stage disk has an air seal integral with the forward
side of the disk.
2) All four stages of blades contain individual interlocking tip shrouds to lower vibratory
stresses and are secured in disk dovetails by means of tab retainers. Blade
platforms provide extended angle wings to improve inner flow path smoothness and
to increase the blade-to-vane spacing to reduce noise generation.
C. Turbine Rear Frame
(1) Turbine rear frame consists of a cast outer casing with integral flanges and strut ends, a hub
with inner strut end casings, 12 semi-tangential struts, stationary oil seal support, inner flow
path liner, and sump service piping with hot air deflectors.
(2) Turbine rear frame provides following structural and aerodynamic functions:
(a) Supports low pressure turbine rotor through No. 6 roller bearing in sump.
(b) Forms a smooth aerodynamic transition into exhaust system.
(c) Provides service piping for No. 6 bearing lubrication.
(d) Attaches to low pressure turbine stator case, houses rear main engine mount, and
supports exhaust nozzle.
(3) Frame Structure
(a) Turbine rear frame is aft structural support of engine having 12 equally spaced struts
supported by rings at both hub and outer diameter. Inner ring, or hub, is a one piece
fabrication which provides a smooth transition into struts. Outer casing with integral strut
ends assures a uniform transfer of strut to ring loads into outer case structure.
(4) Bearing Area
(a) Sump stationary oil seal support is a one piece flanged casting which is bolted to turbine
rear frame forward inner flange inner diameter. Stationary oil seal is composed of oil seal,
No. 6 bearing housing, No. 6 bearing tube jet, No. 6 bearing sump cover seal, and a
sump insulation blanket.
767
AIRCRAFT MAINTENANCE MANUAL
CF6-80A SERIES ENGINES
72-50-00
NoC
Page 7
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
To Next Page
Loading...
