A Study on Hourglass Worm Gearing With Developable Tooth Surfaces

The authors developed a new type of hourglass worm gearing based on the authors’ own theories [1, 2]. The worm having the developable tooth surface can be ground precisely. The pair of the tooth surfaces of the gearing have comparatively small relative curvature and contact with each other with the contact line lying perpendicularly to the relative sliding velocity. The manufactured gears showed the efficiency of 80 percent with the authors’ experimental apparatus without trouble in continuous running test over 3000 hours. Conditions are: reduction ratio, 40; center distance, 100 mm; input power, 3.7 kW; rotating speed of the worm, 1800 rpm.