The influences of an optimum cross-section and beads on the expansion of a torque converter toroidal shell under internal pressure and rotation

A new torque converter structure that looks like a toroidal shell under a high pressure and rotation has been analyzed in order to reduce weight and ballooning deformations, and to increase the stiffness of the structure by using the finite element analysis, shape optimization of a front cover structure, and creation of beads with accurate loadings, such as a dynamic pressure. The curved cross-sectional shape of the circular front cover structure, which produces large ballooning, has been calculated by the FEM-based shape optimization. The creation of beads on a front cover was studied to further increase the structural stiffness. The sizes and locations of the beads were also investigated using FEM. The new model with beads and an optimum cross-section shows 10% less ballooning, 0.5 mm less thickness, and 33% less von Mises stress, compared to a model without beads and optimization because of the enhanced stiffness. A prototype torque converter was fabricated and tested for ballooning under pressurization and high-speed rotation. A good correlation was achieved, judging from the 3% gap between experiment and analysis.