Residual Stress and Bending Fatigue Strength of Case-Carburized Thin-Rimmed Spur Gears with Symmetric Web Arrangements - Effects of Carburized Parts, Rim and Web Thicknesses

摘要

This paper presents a study on effects of carburized parts on residual stress and bending fatigue strength of case-carburized thin-rimmed spur gears with symmetric web arrangements. A heat conduction analysis and an elastic-plastic stress analysis for the case-carburizing process of thin-rimmed spur gears with symmetric web arrangements were carried out by the three-dimensional finite-element method (3D-FEM), considering changes of the thermal expansion coefficient and of the yield stress with the temperature and the carbon content distribution, and then residual stresses were obtained. Effects of the case depth, the carburized part and the rim thickness on the residual stress of case-carburized thin-rimmed spur gears were determined. Bending fatigue tests were carried out for case-carburized thin-rimmed spur gears with symmetric web arrangements, and S-N curves and bending fatigue limit loads were obtained. Effects of the case-depth, the carburized part and the rim thickness on the bending fatigue strength of the case-carburized thin-rimmed spur gear with symmetric web arrangements were determined.