Gear design considerations

This paper discusses the parameters of gears and gear lubrication that affect wear, pitting, and scoring. Formulas for sliding and rolling velocities and for relative radii of profile and lengthwise curvatures between gear teeth are listed. The effects of load sharing between teeth are considered, and formulas for contact stress are developed. The duration of tooth contact and the variation in coefficient of friction are considered. The aspects of oil film thickness and critical temperatures are presented in relation to gear tooth wear and scoring. A discussion of gear testing and simulated gear testing by means of rollers emphasizes the advantages of each.