A new profile for the worm gear drive of a spiral gear

The worm-spiral wheel frontal gear, known as the Helicon gear is a constructive variant of the worm gearing. The advantage of this construction is the reduced overall size in the plane of the spiral wheel, if compared with the usual worm gearing. This paper presents the geometrical modeling of this gearing type in order to define its constructive elements. It is accepted that in the proposed modeling the worm is an Archimede's worm, due to technological considerations. It also studies the constructive variant of the worm gear which ensures a longer contact line, with influences on the reduction of the gear loading. It also presents the constructive form of the new hob mill for the milling of the in-plane wheel of the spiral gear. Experimental measurements are presented for the input and output torque of a reducer with spiral gear, with a circular axial profile worm. (paper)