The kinetic property affected by the clearance between the outer rotor and the cylinder was analyzed with ignoring the influence of other clearances. The influence of the gap between gears was studied in detail. Numerical iterative method was employed in calculation for an example. The deflection angle of the outer rotor

the sequence number of teeth on the outer rotor taking part in the meshing process and the actual generating angle of the inner rotor were obtained. The result shows that the clearance between the outer rotor and cylinder will cause impact effect during the start-up process and the gap between gears will transform the ideal multi-point mesh into the actual one-point mesh. If the rotate speed of the shaft was constant

the gap would cause the speed fluctuation of the outer rotor.