Hourglass Worm Tooth Modification Using CNC-Hobbing Machine.

Abstract

This paper describes a new method for hourglass worm tooth modification using a CNC-hobbing machine. In the hourglass worm gear modified by this method, the worm tooth surface never contacts the mating wheel tooth surface at the end of worm tooth thread when the wheel tooth surface becomes worn. This modification method was applied to the design of an hourglass worm gear with arcuate tooth profile. In the case of tooth surface generation, the hobbing machine was controlled with an external control unit connected to a personal computer by using a manual handle interrupter attached to the hobbing machine.