3D Mesh Generation for Static Stress Determination in Spiral Noncircular Gears Used for Torque Balancing

Abstract

Standard procedures available for evaluating gear fillet stresses are targeted to circular gears where little information is available about noncircular gears. In this paper, a mesh generation algorithm is presented for the discretization of gear tooth profiles of noncircular gear elements for static stress evaluation using FEM (Finite Element Method). The procedure assumes that the noncircular gear tooth profile is known. Delimiting a tooth domain from the gear structure and subdividing it into sectors, the gear tooth mesh is generated by mapping pregenerated patterns into the sectors. The discretized tooth domain is used in conjunction with the FEM to obtain stresses within the tooth fillet region. For comparison, this procedure was applied to determine the stress distribution in circular gears and rectangular beams. The results were in complete agreement with existing analytical solutions. An illustrating example is presented where a noncircular gear pair is introduced to eliminate the speed and torque fluctuation that exists in an electrical generator when an I.C. engine is used as the power source for the generator. The maximum fillet Von Mises stress is calculated for each angular position of the noncircular gear pair.