A NOVEL FINISH HOBBING METHODOLOGY FOR LONGITUDINAL CROWNING OF A HELICAL GEAR WITH TWIST-FREE TOOTH FLANKS BY USING DUAL-LEAD HOB CUTTERS

摘要

In the gear finish hobbing process, to obtain a twist-free tooth flank of helical gears, a novel hobbing method for longitudinal crowning is proposed by applying a new hob's diagonal feed motion with a dual-lead hob cutter. Wherein the hob's diagonal feed motion is set as a second order function of hob's traverse movement and tooth profile of hob cutter is modified in a dual-lead form with pressure angle changed in it's longitudinal direction. The proposed method is verified by using two computer simulation examples to compare topographies of the crowned work gear surfaces hobbed by the standard and dual-lead rack cutters. The results reveal the superiority of the proposed novel finish hobbing method.