The meshing frequency of gears refers to the meshing times of teeth in unit time. For NGW type planetary gear system, the calculation method is different according to different fixed central members. The calculation method is as follows.

When the inner ring gear is fixed:

When the sun wheel is fixed:

When the planet carrier is fixed:

Where:

Zi, Ω I — the number of teeth and the rotation frequency of the corresponding gear respectively, (I = s, R).