Development of surface wear and lapping simulation models for hypoid gears

Surface wear is one of the failure modes observed in real-life hypoid gear sets impacting the contact patterns and the resultant noise behavior. In this study, a model is proposed to predict the surface wear of face-milled or face-hobbed hypoid gear pairs. This wear model incorporates Archard's wear model along with loaded hypoid gear tooth contact models of different types. It combines the sliding distances computed from kinematic conditions with contact pressures predicted by the contact models to find the wear distributions along the tooth surfaces. The contact pressures are obtained along the contact zones at each rotational gear position. This model is applied to a family of hypoid gear pairs having different shaft offset values to show that a larger shaft offset results in larger sliding distances and larger wear depths. Influences of the gear and pinion position errors on the resultant wear patterns are also quantified by using the wear model.;In order to reduce the computational time required by the wear simulations, an approximate method is proposed that devises an interpolation scheme to patch instantaneous wear profiles predicted at a small number of rotational increments. This approximate model is used to perform families of wear simulations with time varying gear and pinion position errors in an attempt to simulate a typical lapping process used for face-hobbed hypoid gears. As required by the lapping simulation methodology, the sensitivity of the contact positions to the magnitudes and directions of the mounting errors are quantified through the differential geometry. At the end, complete lapping simulations of hypoid gear pairs having theoretical surfaces as well as surfaces having manufacturing errors are carried out, and the influence of the lapping processes on the motion transmission error amplitudes are quantified.