Comparative Analysis of the Mechanical Behavior of Conjugated Face-Milled and Face-Hobbed Hypoid Gear Drives

Abstract A comparative analysis of the mechanical behavior of conjugated face-milled and face-hobbed hypoid gear drives is presented. The analytical determination of the basic machine-tool settings is conducted for both systems of generation and applicable to hypoid gear drives at any shaft angle, assuring the absence of kinematic transmission errors. However, the implementation of a tip relief is required to ensure a smooth load transition between consecutive pairs of teeth while preserving the conjugated action between tooth surfaces. The impact of the generating process and cutter radius selection on contact stress, bending stress, loaded transmission errors, efficiency, and sensitivity of the contact pattern to the presence of errors of alignment is presented. The comparative analysis reveals a similar mechanical behavior for both systems of generation, although in face-hobbed hypoid gear drives it is possible to slightly reduce the level of contact stress compared to face-milled hypoid gear drives for the same cutter radius selection. Furthermore, although increasing the cutter radius provides a modest reduction in contact stresses, a detailed sensitivity analysis of contact pattern shifts due to alignment errors highlights the importance of selecting the cutter radius within the lower bounds of the range recommended by the Information Sheet AGMA 22849-A12.