Page 297 - Gear Technology Solutions

contact pattern position, which is why the backlash adjustment in the assembly
is done by shifting the gear axially (G) until the correct backlash is obtained. In
case of miter gears, both the pinion axial position P and the gear axial position
G influence the backlash equally. However, shifting only one of both will also
change the contact pattern position. In case of small changes within the toler-
ances shown in Table 2 (equal for pinion cone P and gear cone G) the contact
movements are within permissible limits.

Table 3: Straight bevel gear shaft positioning tolerance table

The tolerances in Table 3 were compiled for straight bevel gears. The offset
tolerance allows equal positive and negative deviations. The pinion cone toler-
ance prohibits negative values due to the risk of metal-to-metal tooth jamming.
The positive P tolerance is rather large, because of the small effect to the
backlash. Backlash is commonly adjusted by changing the gear cone during
the bevel gear assembly. A gear cone deviation tolerance which will change
the backlash by +/-50% of the backlash range is shown in the table. (range
equal maximum backlash - minimum backlash).

Table 4: Miter spiral bevel gear shaft positioning tolerance table

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