Abstract
Abstract
This paper presents a general method to determine the critical modification coefficient (CMC) for a cylindrical worm gear drive with the worm generated by a surface of revolution. Unlike the existing methods for the determination of the first boundary points, to avoid tedious partial derivatives the curvature information of generating surface and relative motion parameters is directly applied to the worm and the concept of equivalent generation is applied to obtain an explicit form of the equation of meshing; thus it is a very efficient way to determine the first boundary points on the worm gear tooth surface. By solving a system of non-linear equations, the CMC can be obtained and the gear undercutting can be avoided. On the basis of the proposed method, a computer program is created and applied to four commonly used worm gear drives: ZK1, ZK2, F-I and F-II.