抄録
This paper described a study on effects of the case depth, the helix angle and the carburized part on the residual stress, bending fatigue strength and the bending fatigue crack path of case-carburized helical gears. A heat conduction analysis and an elastic-stress analysis during the case-hardening process of helical gears were carried out for various case-hardening conditions by the three-dimensional finite-element method (3D-FEM), and then residual stresses were obtained. The effects of the case depth, the helix angle and the carburized part (tooth surface, gear-side) on the residual stress were determined. Bending fatigue tests of case-carburized helical gear pairs of different case depths, helix angles and carburized parts were carried out, and S-N curves were obtained. Effects of the case depth, the helix angle and the carburized part on bending fatigue strength and the bending fatigue crack path of case-carburizing helical gears were determined. Furthermore, the relationship between the residual stress and the bending fatigue strength was examined.
