A Study on Hourglass-Worm Gearing Designed to Concentrate Surface Normals. A Gear Design Using an Hourglass-Worm Gearing Whose Worm Tooth Surface Is Generated by the Grinding Wheel with an Involute Helicoid.

Abstract

Displacement of the worm axis relative to the wheel axis under load is considered to be the helical movement rotating about the instantaneous axis. In order to avoid the influence of the displacement of gear axes under load upon tooth contact, the authors propose that the surface normals should be intersected perpendicular to the direction of helical velocity of the displacement. This idea was applied to the gear design using all hourglass-worm gearing whose worm tooth surface is generated by the grinding wheel with an involute helicoid. Numerical analyses indicated that as much as 80% of the theoretical area of the utilized gear contributed to meshing at their estimated displacement positions.