MODEL
12
0
CRAWLER
UNDERCARRIAGE
1.
Carbody
and
Turntable
Bearing
RING
GEAR (INNER
RACE)
OUTER
RACE............
~
0
BOLTS
TO
0~
TURNTABLE
r
I
ID
I
~
I
1
l
.,,c.-----::.,
I I
CARBODY
Figure 21. Carbody and Bearing
The Carbody and Turntable Bearing
The Carbody
is
the
welded steel structural which
Joins
the
track frames and supports
the
upperstructure. It
is
fastened
to
the
track frames by
twenty-four bolts and
is
adjustable
to
two
traek
widths.
The turntable bearing consists
of
an inner and an
outer
race, with a single row
of
steel balls
at
its
center. The inner race
is
welded
to
the
carbody and
remains stationary. The
outer
race
is
bolted
to
the
upperstructure and rotates with it.
A large ring gear forms
the
inner race
of
the
bearing.
The teeth of
the
ring gear mesh with
the
Swing
Gearbox
output
pinions, and as
the
pinions rotate,
they· walk around
the
ring gear and cause
the
turntable
to
rotate.
Scheduled Maintenance
Periodically check
the
carbody for loose bolts. When
retracting
or
extending
the
tracks,
all
twenty-four
bolts must be re-installed,
then
torqued
1800
lb-ft
(2450
Nm).
IMPORTANT:
Remove track motor
guards
before extending or
retracting track frames to prevent damage to
drive motors.
Lubricate
the
Turntable Open Gear daily
or
every 10
hours. Lubricate
the
Turntable Bearing once a week
or
every 50 hours. Apply grease
to
the
Bearing
through
the
Central Lube fitting
in
Cab
(see
Pictorial
Listing
of
Lubrication Fittings) while slowly rotating
the
Turntable through several revolutions.
17
To Next Page
