Effects of Rim Thickness on Root Stress and Bending Fatigue Strength of Internal Gear Tooth

Abstract

This paper presents a study on the effects of rim thickness on root stress and bending fatigue strength of internal gear tooth. A root stress analysis by the 2-dimensional finite element method (FEM), a static loading test and a bending fatigue test for internal gears of different rim thicknesses were carried out. The root stresses increase with a decrease in rim thickness on both the tensile and compressive sides. The bending fatigue-limit-load of the thin-rimmed internal gears decreases with a decrease in rim thickness for lw<3m and remains almost constant for lw≥3m. The validity of the calculating formula of tooth bending strength of internal gear proposed by ISO was examined on the basis of the results of the static loading and the bending fatigue tests.