Meshing Limit Line of Involute Worm Drive

Abstract

The theory to compute the meshing limit line of an involute worm pair is fully established on the basis of the meshing theory for gear drives. Some basic and important results are obtained, such as the meshing function and the meshing limit function. Unlike other types of worm drive, the equations of the meshing limit line and its conjugate line can be attained in two-parameter form for an involute worm pair. In general, there is only one meshing limit line on the tooth surfaces for an involute worm gearing, who always locates in the middle of the worm thread length. From the viewpoint of this, the working length of an involute worm generally cannot exceed the half of the thread length. On the other hand, the conjugate line of the meshing limit line usually locates in the middle of the worm gear tooth surface. As a result, the whole conjugate zone on the worm gear tooth surface is divided into two parts. This means that there are two sub-conjugate zones on the worm gear tooth surface. The numerical example is provided for validation and verification.