Optimum design of teeth shapes of rotating serration and spline-type torque converter parts operating in a high temperature fluids

The tooth shapes of serration-type and spline-type reactors are optimized using finite element methods to improve the working life of the part and to lower the stress concentration during rotation resulting from contact with the outer race for a reactor operating with 170°C transmission oil. The results of thermal expansion analyses between an Al reactor and the steel outer race indicate that, before optimization, the gap between the two parts increases further as the serration-type reactor expands by 0.1 mm and the spline-type one strains by 0.08 mm. Because of shape optimization, a trapezoidal shape is obtained from the initial triangular serration and the rectangular spline of the two reactors. The maximum von Mises stress of the serration-type convertor decreased by 24.5 %, and by 9.3 % for the spline-type convertor. In addition, there is a 13 % reduction in the axial thickness, as compared to the initially designed model.