Selecting the Number of Teeth on a Planet for a simple planetary set 4

[Spurs]

How is it possible in a simple planetary gear set that the tooth count on the planet gear can be adjusted plus or minus one tooth without affecting timing while trying to maintain equally spaced planets.

As an example, if you had a sun gear with 18 teeth and a ring gear of 60 teeth, and you wanted 3 equally spaced planets, why is possible (according to AGMA 6123) to choose the number of teeth on the planet of either 20, 21 or 22 teeth and not affect the timing or efficiency of the mesh. I would think in such a case 21 teeth would be ideal, and selecting 20 or 22 teeth would result in an unequal load sharing (and hence efficiency loss).

Cany anyone shed some light as to why this is the case

 

[carburized]

Spurs

Of course the action is not as smooth. Now you taking away from the contact ratio. All I am saying to you is, if you have a negative shift on the planet you will have loss in stregtn as the planet is always in reverse bending. You are correct in saying the timing is not proper on all the planet. When I say proper means having a nice contact ratio.