Effect of Hardness on Tooth Strength and Surface Durability and on Failure Modes of Gears

Abstract

In order to elucidate the effect of surface hardness on tooth strength and surface durability and on failure modes of gears, fatigue tests were conducted. The results obtained are summarized as follows : There are hardness ranges in which pitting, tooth breakage and spalling will break out. The degree of tooth profile deterioration can be used as a measure to evaluate the life for pitting. At the fatigue limit load, the dynamic load increase which is induced by tooth profile deterioration is not so large as to be taken into consideration. The failure mode and fatigue life can be affected by the performance of lubricant.