Computer Aided Design of Hobs for Gear Manufacture of the Worm Gear Drive with Ground Worm

Summary

The shape of the ground worm is determined by the geometry and the kinematics of the grinding. Due to the helical generating motion of the grinding wheel with straight-lined profiles, the ground worm possesses a curvilinear profile both in the axial and the normal section.

The prerequisite for the correct worm gear pair mating is, that the worm gear should have the adequate conjugated tooth surface. Therefore, the worm gear manufacturing should he done with a hob whose generation surface corresponds the ground worm surface. The design of such a hob requires a complicated calculation and only the use of a computer makes it possible. The method of the computer aided design of such a hob is presented in this paper.

This method has been applied to the products of the company “Jugoalat” in Novi Sad, and found accurate and useful.