A SURFACE PITTING LIFE MODEL FOR SPUR GEARS .1. LIFE PREDICTION

Surface pitting is a major failure mode for gears. Estimation of failure probability and service life are important in gear design. Current techniques give only a pass/fail rating based on semi-empirical methods. A predictive model for estimating service lives and failure probabilities has been developed. This paper discusses the life prediction analysis, which is based on propagation of a surface breaking crack under rolling/sliding contact conditions. The effects of both surface roughness and nonmetallic inclusions can be included. While predicted lives are lower than expected, trends observed through parametric variation are consistent with service behavior.