Effects of Gase-Carburized Parts on Residual Stress and Bending Fatigue Strength of Case-Carburized Thin-Rimmed Spur Gears with Symmetric Web Arrangement

Abstract

This paper presents a study on effects of case-carburized parts on residual stress and bending fatigue strength of case-carburized thin-rimmed spur gears with symmetric web arrangement. A heat conduction analysis and an elastic-plastic stress analysis during the case-carburizing process were carried out for various case-carburizing conditions by the three dimensional finite-element method (3D-FEM), considering changes of the thermal expansion coefficient and the yield stress with the temperature, and then residual stresses were obtained. Bending fatigue tests were carried out for different case-carburized thin-rimmed spur gears with symmetric web arrangement. Effects of case-carburized parts on the residual stress and the bending fatigue strength were examined. These results were also compared with those of solid gears.