Gear Bending Stress Analysis of Automatic Transmissions with Different Fillet Curves

Abstract

Gear bending strength is a core indicator to indicate reliability and operation performances of automotive transmissions. Fillet curve design of dedendum of gear teeth can improve their bending stress and complex tooth contact perfor-mance. Geometrical parameters of gears are considered important for the varia-tion of stresses in the design of gears. Bending stress analysis has been a key area of research to minimize failure and optimize design. This work presents a finite element (FE)-based analysis method of gear bending stress, which can be used for multiple spatial meshing gear teeth simultaneously. Three-dimensional (3D) models of helical gear with double and single circular fillet curves are estab-lished by using Pro/ENGINEER. By changing of meshing positions of gears, tooth contact analysis results along their paths of contact are obtained. Since FE-based tooth contact analysis are performed based on 3D models, the results of bending stress are reliable and authoritative. It is proved that bending stress of the gear with double circular fillet curves is 1.3~1.5 times as that of the gear with single circular fillet curves, which means that gear with single circular fillet curves has better loading capacity than gear with double circular fillet curves. The study will provide a good method for studying gear bending stress to improve gear de-sign of automotive transmissions.