To double-crown an involute helical gear, a hobbing method is proposed by setting the hob's diagonal feed motion as a second-order function of hob's traverse movement and modifying the tooth profile of hob cutter into a dual-lead form with pressure angle changed in its longitudinal direction. Merits of the proposed double-crowning method are also verified by using three computer simulation examples to illustrate and compare the topographies of tooth flanks, contact ellipses, and transmission errors under various assembly errors of the double-crowned gear pairs with those produced by using the conventional modified hob cutter and dual-lead hob cutter. Computer simulation results reveal the advantages of the proposed hobbing method for involute helical gear manufacturing.

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