NOTE
When installing carrier to gear housing,
ensure alignment of flange mounting holes is
correct (see Fig. 2.10)
3.
Place the carrier on the gear housing ensuring
gear teeth are meshed. Temporarily fasten by
tightening at least three of the six screws
supplied with the gearbox. Rotate the pinion
gear to make sure it turns freely.
4.
Attach the drive unit backlash tool to the
gearbox as shown in Fig. 2.11. Make sure the
dial indicator is aligned as shown.
5.
Install the flag assembly on the spur gear with
the flag in the upright position.
6.
Rotate the flag until it moves about halfway
into the dial indicator's range of motion.
Then, rock the flag back and forth (firmly, but
not hard enough to rotate the motor shaft) and
observe the dial indicator readings. The
difference between the highest and lowest
reading is the backlash.
Backlash should be
greater than 0.003" but should not exceed
0.013".
Check backlash at every other tooth
for a full revolution. If this condition is not
met, disassemble the carrier from the gear
housing and add or remove shims as required
(if backlash is too great, remove shims; if
backlash is too small, add shims). Repeat
these steps as necessary until backlash
conditions are met.
7.
Once backlash conditions are met, remove
the flag assembly and backlash tool. Rotate
the motor shaft several revolutions both
forward and reverse. Remove the carrier
from the gear housing and observe the
contact pattern on the gear:
a. The correct pattern, as shown in
Example 1, is well centered on the bevel gear
tooth with lengthwise contact clear of the toe.
The length of the pattern in an unloaded
condition is approximately one-half to
two-thirds of the bevel gear tooth. The
backlash (6-hole) and motor to gear box
(4-hole) shims are correct.
b. Example 2 indicates an incorrect 4-hole
shimming package between the motor and the
gear housing. The contact pattern in the left
illustration indicates that the pattern is too
close to the root of the gear tooth or off the
tooth root. If this condition occurs, add some
4-hole shims between the motor and the
gearbox and test again. The illustration to the
right shows a pattern that is too close to the
tooth top land and off center. If this condition
exists, remove some 4-hole shims between
the motor and gearbox and test again.
c. Example 3 indicates a backlash error
caused by an incorrect 6-hole shim package
between the carrier and the gear housing. The
illustration to the left shows the pattern too far
off the tooth toe. As was noted in Example 1,
there should be an area between the contact
E
lectric
C
ounterbalance
H
igh
O
utput
Drive
12/20/99
2.10
Example 2
Example 1
Figure 2.11 - Backlash Tool
