Meshing characteristic analysis of a cycloid drive with epitrochoid profile and its conjugate envelope

Cycloid drives are widely adopted in the areas of industry robot, aerospace, automotive, etc., due to the advantages of large ratio, compact size and light weight. To improve the transmission efficiency and the load capability, a novel geometric design of the cycloid drive is presented based on coordinate transformation and envelope theory, including the profile generation and modification. The conjugate gear tooth pair is a concave-convex pattern of contact and composed by the epitrochoid profile and its conjugate envelope profile modified by a small fillet. The meshing characteristics, such as the contact zones, contact ratio, sliding coefficients and induced normal curvature are analyzed to estimate the performance of the proposed cycloid drive. The influence of those characteristics in varied geometrical design parameters is also discussed for optimal design. The contact stress is analyzed by using finite element method and a comparison study is conducted to compare with the conventional cycloid drive. The contact stress and sliding coefficients demonstrate a salient feature of the proposed cycloid drive.