Planetary precessional transmission: Geometry and contact bearing capacity, kinematics and profile generation

Abstract

In this study, we propose a new gear with convex-concave multipair contact teeth contact for mechanical transmissions. The paper presents various kinematic structures of planetary precessional transmissions with multiple pair convex-concave gearings and the minimum difference of the flank curves at contact points of the teeth. We examined the influence of the gearings’ geometric and kinematic parameters on the shape of the teeth profiles and the difference in the flank curvatures at the contact points of the pairs of simultaneously conjugated teeth and, respectively, on the bearing capacity of the multiple pair contact. It describes the mathematical modeling of teeth contact with relative sliding friction in the contacts of pairs of simultaneously conjugated teeth depending on the precession angle of the driving shaft. Technical solutions are proposed to reduce the energy losses in the gearings and, respectively, to increase the mechanical efficiency of the precessional transmission as a whole. Technological aspects of the methods of generating conical wheel teeth with a non-standard convex/concave profile developed and patented by the authors are presented, including generation in the Gleason system on numerically controlled multiaxial machine tools. Constructive-functional variants of precessional transmissions with various kinematic structures with multiple pair convex-concave gearings were described, including precessional moto reducers and servo-motor reducers. Technical solutions for the development of precessional transmissions are protected by international patents USA and Germany.