Figure 2-39.--PT rear frame.
bearing housings have flanges to which air and
is installed between nozzle shrouds and casing to
oil seals are attached to form the D sump. The
protect the casing from the high temperature of
frame casing supports the outer cone of the
the gas stream.
exhaust system and provides attaching points for
Rear Frame
the GTE rear supports. The struts provide passage
for lubrication and scavenge oil, C- and D-sump
The PT rear frame (fig. 2-39) has an outer
seal pressurization air, D-sump vent, cooling air,
casing, eight equally spaced radial struts, and a
and PT balance piston air services. The two PT
single-piece cast-steel hub. It forms the PT exhaust
speed pickups also pass through the struts (No.
flow path and supports the aft end of the PT. It
3 and No. 7).
also supports the forward end of the high-speed
flexible-coupling shaft. The turbine rear frame
HIGH-SPEED FLEXIBLE
hub supports the inner deflector of the exhaust
COUPLING SHAFT
system. It also has a bearing housing for the No.
The high-speed flexible-coupling shaft has a
7B and No. 7R bearings. The No. 7B bearing is
forward adapter, which mates with the PT, two
the thrust bearing for the PT. The hub and the
2-32
