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Enlarged...
For gears with small numbers of teeth, you can get thinner teeth than you would like. In particular, the teeth are weaker than the gear it is mating with.
We want to make the teeth on the smaller gear stronger.
There are a number of strategies but they generally involve 2 methods:
1) leaving the larger gear alone and increasing the center distance over the standard distance. The smaller gear then grows ("enlarges") to fill the extra backlash. The how this is done varies, but typically both the OD and the Root Dia. grow.
2) leaving the gears on the same standard center distance and simultaneouly thinning the teeth on the large gear and thickenning the teeth on the smaller gear.
Obviously #2 won't work well if both gears are the same size (one gets stronger, one gets weaker).
Sometimes aon planetary gearsystems they drop a tooth from the planets and add a tooth to the sun and the add 2 or even 3 teeth to the ring gear. This adds gaps that give the gears room to be enlarged.
FYI.
Joe J.
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