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outside diameters of the shaft are precision ground.
Two of the ground
surfaces located near the forward (or closed) end of the shaft are zinc
plated and provide an interference fit upon assembly to the front frame.
The two ground surfaces near the aft (or open) end of the shaft provide
a seat for the bearing inner races.
Four shank nuts are swaged to four
holes inside the forward end of the shaft to provide attachment to the
front frame.
Eight shank nuts are swaged to the flange at the aft end
of the shaft to provide attachment to the rear frame cover plate.
2.15
Bearing System
a.
A two-bearing system consisting of a ball thrust bearing and
a roller bearing, supports the over-hung rotor.
The bearings are mounted
to the shaft which extends from the front frame hub.
The roller bearing
is assembled to the forward end of the shaft; the roller bearing is
assembled to the aft end of the shaft.
The balls, rollers, and races
are made of 52100 steel; the cage material is silver plated bronze.
b. Both bearing inner races are press fitted to the rotor shaft at
assembly.
The inner races are separated by a spacer which is machined
from 'titanium. Both outer races are press fitted to their respective
housings in the hub of the rotor disc.
c.
The ball thrust bearing has a split inner race.
The forward
half of the split inner race contains a puller groove.
The bore diameter
of the ball bearing is 3.9350" - 3.9361".
The tolerance of the bearing is
ABEC-5 grade (aircraft quality).
It contains 14 balls which are 0.5625"
diameter.
The ball bearing is designed to give 600 hour B10 life at a
maximum temperature of 300OF when lubricated with grease.
d.
The roller bearing bore diameter is 3.9350" - 3.9361".
The
bearing has a tolerance of ABEC-5 (aircraft quality).
It contains 20
rollers which measure 0.3937" long by 0.3937" diameter.
The roller bearing
is desi-ned to give 600 hour BI0 life at a maximum temperature of 3001F
when lubricated with grease.
11-2.8
R-1
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