A Novel Finish Hobbing Methodology for Longitudinal Crowning of a Helical Gear With Twist-Free Tooth Flanks by Using Dual-Lead Hob Cutters

Abstract

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.

Generation of a double-crowned involute helical gear with twist-free tooth flanks by a CNC hobbing machine with three synchronous axes

“…The mathematical models of the standard and double-crowned involute hobs are given in [18,19]. Conventionally, a double-crowned involute helical work gear can be achieved through two modifications: making the cross-profile tooth of the hob cutter with a parabolic curve for profile crowning, and making the radial feed movement along the center distance between the hob and work gear with a second-order polynomial for longitudinal crowning.…”

“…Lastly, Hsu and Su [16] investigated the gear tooth surface topologies, contact ellipses, and transmission errors of work gear pairs generated by a modified hob with variable tooth thickness. And Tran et al [17][18][19] proposed a novel hobbing method to generate anti-twist tooth flanks of the involute helical gear in longitudinal tooth crowning by supplementing an additional rotation angle of work gear during its hobbing process.…”

Manufacturing helical gears with double-crowning and twist-free tooth flanks using a variable pressure angle shaving cutter

“…18 Ling et al 19 proposed two gear-grinding techniques to improve pitch deviations in ultra-precision gears: the offset-compensated technique and the neighbour-tooth translocation technique. Recently, Tran et al 20,21 proposed a methodology for finish-hobbing of twist-free tooth flank of helical gears for longitudinal tooth crowning by setting the hob's diagonal feed motion as a second-order function of the hob's traverse movement and using a dual-lead hob cutter wherein the pressure angle changes in its longitudinal direction. Wang et al 22 presented a milling method and a milling principle for generating a spur face gear using a five-axis computer numerical control milling machine.…”

A Method for Generating Helical Surface of the VPA Hob on a CNC Worm Grinding Machine

“…Ophey and Reimann [13] introduced a thermomechanical model for describing influence on the surface zone in the gear generating grinding process. Recently, Tran et al [14], [15] proposed a novel hobbing method to free twist tooth flanks of the longitudinal crowned helical gear by using variable pressure angle hob cutter on CNC hobbing machine. Besides, the topologies, contact bearings and transmission errors of the double-crowned work gear pairs generated by a modified hob in the gearhobbing process are investigated.…”