Abstract: A method for determination of load distribution along the instantaneous contact lines of worm threads and gear teeth is presented the bending and shearing deflection of them, the contact deformation, the axial deformation of worm body, and the manufacturing and alignment errors of the worm and gear are studied followed by the resolution of the integral equations with approximation and an iterative technique for the load distributions of both the classic and the new type of double enveloping worm gear drives. Analysis is also carried out for the influence of design parameters on load distribution.

Key words: Contact line, Double enveloping, Load distribution, Worm gear drive