According to kinematics method of gear geometry principle

the tubular enveloping surface is firstly proposed.It is generated by the sphere motion along an equidistant curve which is developed based on a selected smooth curveГattached to the planetary wheel external tooth surface in the given direction.The new meshing pair is formed in terms of the established tubular surface and the general equations of gear pair are derived.Then the generation of tooth profiles of planetary wheel drive is discussed.Meanwhile

the conjugated contact curve for selected smooth curveГis determined. Finally

the meshing characteristics of point-contact involute planetary gear transmission with small teeth difference are also discussed.The point-contact engagement pair of this gear drive has the property of low sliding condition and high transmission efficiency

etc.