After adjusting the pre-load of the planetary gear case bearings and the crown gear and pinion teeth backlash, it will be indispensable to control, and if necessary, to adjust the contact pattern of their teeth.
The correct contact pattern will be obtained varying the depth of the pinion or teeth backlash, and it is of fundamental importance for the durability of the assembly.
Checking the contact pattern
1 | Apply gear-marking compound on two teeth of the ring gear displaced 180° to each other |
2 | Spin the pinion forward and back braking the ring gear at same time with a hard wood piece |
3 | Compare the obtained contact markings with the examples below |
If necessary: | |
| |
Carry out the required corrections. |
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In practice, generally the ideal contact pattern is not obtained. However, it is important that they do not touch in any place the outside edge of the tooth surface.
Correct contact marks |
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Contact markings on the tooth flank |
4 | Increase a little bit the assembly distance (basic measurement) of the pinion. |
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Contact markings on the tooth face |
5 | Reduce the assembling distance (basic measure) of the pinion. |
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Contact markings close to the thicker flanks of the tooth |
6 | Bring the pinion closer the ring gear |
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Contact markings close to the thinner flanks of the tooth |
7 | Move the pinion away from the ring gear |
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