Page 299 - Gear Technology Solutions

For hypoid gearsets, which are the subject of Table 6, the offset tolerance E
only allows positive deviations. Already small amounts of negative offset devia-
tions would diminish the backlash rapidly. The tolerances for pinion cone P,
gear cone G and shaft angle ALPHA are identical to spiral bevel gears. Differ-
ent to spiral bevel gears is the contact displacement which is 30% to 40% less
for hypoid gears. The reason is to one part that the tolerance in E direction is
only positive and to a second part that hypoid gears are typically less sensitive
than spiral bevel and straight bevel gears.

Table 6: Hypoid gear shaft positioning tolerance table

The last bevel gear category covered in Table 7 of this guideline is super re-
duction hypoids (SRH). While the tolerance in offset (E) is equal to hypoid
gears, the pinion cone tolerance (P) has a plus/minus value because of the
slim pinion cone, which has only a very small influence to the backlash. The
gear cone tolerance (G) is smaller than for hypoid gears, which is justified with
the higher sensitivity regarding top-root contact and fillet transition interfer-
ence. SRH gearsets have the same shaft angle tolerances as all other bevel
gear types and contact displacement limits are identical to spiral bevel gears..

Table 7: Super reduction hypoid gear shaft positioning tolerance table

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