Abstract
A harmonic drive reducer is composed of a flexible cup gear, a rigid ring gear, and an oval cambearing. Concerning the torsional stiffness of the reducer, torsional and radial bending deformations of the flexible cup gear were measured under torque-loaded conditions. The effect of balls in the oval cam bering on the torsional stiffness was also investigated experimentally. It is found that the radial deformation of cylindrical part of the cup gear goes inside in the 90 deg. angular region measured form the major axis of oval cam toward the torque-loaded direction, and that the ball bearing in this region are subjected to radial forces and have a large influence on the torsional stiffness of the reducer. The above deformation is ascertained by FEM calculations taking account of some constraints of gear meshing and the radial stiffness of the balls.
