Parameter design of double-circular-arc tooth profile and its influence on meshing characteristics of harmonic drive

Abstract

In this paper, a design method of double-circular-arc tooth profile for harmonic gear based on curve mapping and bidirectional conjugation is proposed. By considering the kinematic principle of harmonic drive, the curve mapping is used to solve the addendum circular arc, and on this basis, the dedendum circular arc is solved by the bidirectional conjugation. The influence of design parameters on the tooth profile shape and meshing characteristics of harmonic gear drive are analyzed. The results show that the proposed tooth profile design method can not only construct the mathematical relationship between basic parameters (modulus, number of teeth, deformation, etc.) and tooth profile shape, but also realize the multi-tooth engagement of harmonic drive. The change of the scaling coefficient has a great effect on the tooth profile shape. The increase of flexure coefficient will reduce the pressure angle of the tooth profile, and the smaller flexure coefficient is beneficial to reduce the maximum Von-Mises stress of the flexspline during assembly and loading stage. The research results will provide a novel design method for the tooth profile and improving meshing characteristics of harmonic gear.