– 7 –
Correct Pinion & Gear Tooth Contact Patterns
Incorrect Ring Gear Tooth Contact Pattern
Figure 5. Tooth Contact Pattern Correct and Incorrect
Example:
Pinion setting distance of old gear
2.883
Pinion settinq distance of new qear
2.878
Difference
.005
Remove .005 from shim gap.
3.
Install shims (Item 2.3) and pinion cage sub-assembly
(Item 2). CARE MUST BE TAKEN NOT TO DAMAGE the
pinion gear teeth by forcing them into the ring gear teeth.
GEAR SETTING PROCEDURE
The proper mounting of the gear set is essential to obtain long
life and smooth operation of the gears. The pinion and ring
gears were positioned approximately in the preceding steps.
The correct gear position is determined by the gear tooth
contact pattern and by the backlash.
With the “X” marked tooth on the pinion gear engaged between
the two “X” marked teeth on the ring gear, check the backlash
with a dial indicator as shown in Fig. 3. Lock the pinion shaft
against rotation. The amount of movement of the fan shaft,
measured at a distance equal to the outside radius of the ring
gear is the backlash. The backlash on all gear ratios should be
between .005 and .012. With the “X” teeth engaged the
backlash should be approximately in the middle of the allow-
able range. Adjust the ring gear axially until the proper back-
lash is obtained. Check the backlash at three other points
around the ring gear to be sure the backlash is within the
specified limits. The fan shaft disc and the standard place bolts
may be used to adjust the ring gear in either direction. After the
correct backlash is obtained, remove fan shaft disc and mea-
sure the distance from the end of the fan shaft with a depth
micrometer. Install a shim pack (Item 5.1) equal to this depth
and replace the disc. (Tighten the inside bolt circle before
tightening the outside bolt circle. Use 85 to 90 foot pounds
torque.)
Recheck the backlash to make sure it is within the proper limits.
With gears adjusted to the proper backlash, blue (Prussian
blue in oil) the pinion teeth. (By using a long handled brush or
swab, the pinion teeth can be reached through the inspection
opening.) Drive the pinion by turning the fan shaft in both
directions for several revolutions. Observe the markings on
both gears on both sides of the teeth. Compare the markings
with the contact pattern shown in Figure 5. If contact pattern is
incorrect, adjust the pinion position with shims between the
pinion cage cap and Geareducer case.
When tooth contact is correct, recheck backlash. If necessary,
adjust ring gear to obtain proper backlash and recheck contact
pattern. Proper contact is the more important of the two. On a
used set of gears, it may be necessary to set the gears with
slightly greater backlash in order to obtain proper tooth con-
tact. Should a condition be encountered where correct contact
cannot be obtained, the Geareducer should be returned to
Marley’s Olathe, Kansas plant in exchange for a factory
reconditioned unit.
FINAL ASSEMBLY
1.
Apply 1/8" diameter bead of Permatex No. 2 to flange of
bottom cap. Bead to be centered on flange, and to be
inside of and adjacent to bolt holes (see Figure 4).
2.
Install bottom cap and tighten attaching cap screws to 25
ft./lbs. torque.
3.
Install “O” ring (Item 17) in water slinger (Item 7).
4.
Fill grooves of the labyrinth ring (Item 8) and water slinger
(Item 7) with a lithium base grease (NLGI-2).
5.
Install water slinger on fan shaft (Item 10).
6.
Replace air vent and all pipe plugs.
7.
Fill with lubricant selected from Table 1, page 8. Refer to
Geareducer Service Manual for complete service and
lubrication instructions.
