The gas producer compressor assembly is supported at its
forward end by the No. 1 main bearing, figure 4.6, which is a ball
bearing to absorb thrust and radial loads, mounted within a leaf
spring retainer that dampens minor torsional vibrations. The aft
side of the bearing is sealed by a positive contact carbon seal aided
by springs and pressurized air. A radial labyrinth seal is located
forward of the carbon seal, operating on pressurized air through
bleed holes; it assists in positive sealing of the bearing area. The
forward end of the power shaft is supported by an unnumbered roller
bearing within the inlet housing. All main bearings may be seen by
referring back to figure 4.4.
The following subparagraphs give some information about the
T53L13 output reduction carrier and gear assembly and the T53L701
propeller reduction carrier and gear assembly.
a. Output reduction carrier and gear assembly on the
turboshaft engine in the T53L13 is located in the inner inlet
housing as shown in figure 4.7. It consists of the support housing
(1), carrier assembly (2), three planetary gear assemblies (3), oil
transfer tubes (4), an output gear shaft (5), and a torquemeter
assembly (not shown). The sun gearshaft is splined and bolted to the
forward end of the power shaft and drives the three planetary gears,
which in turn drive the output gearshaft. Reduction ratio of the
turboshaft engine is 3.2 to 1.
b. Propeller reduction carrier and gear assembly used in the
T53L701 engine utilizes a revolutionized reduction gear system
called split power gearing. This type of power gear system has the
ability to absorb greater torque loads, which permits the delivery of
increased horsepower. Figure 4.8 is a cross sectional view of the
split power reduction gear system. The power turbine speed reduction
is accomplished within the split power gearing by primary and
secondary drive systems, with power being transmitted to the
propeller shaft through each of these systems.
ACCESSORY DRIVE ASSEMBLY
This assembly provides drive for both the N1driven accessory
numbers in parentheses in the following paragraphs are used in figure
4.9 to show the accessory gear drives.