Optimization of hypoid gear macro/micro geometries for high efficiency drives, taking into consideration NVH and strength

摘要

Continuous improvement of vehicle fuel economy is strongly needed to protect the global environment and save energy. One effective way to improve the fuel economy of vehicles is to reduce the meshing friction of hypoid gear drives. However, it is known that reducing hypoid gear meshing friction adversely affects noise, vibration and harshness (NVH) and strength. A method of predicting hypoid gear meshing efficiency with high accuracy was previously proposed to design high-efficiency hypoid gears. A more precise method of predicting hypoid gear meshing efficiency was newly developed by calculating the load distribution, sliding velocity, and coefficient of friction on each meshing point along the path of contact, taking into account not only the gear dimensions but also actual tooth micro geometries. In this study, hypoid gear macro/micro geometries were optimized for high efficiency drives by using our newly developed prediction method. The influence of hypoid gear macro geometries (gear dimensions) and micro geometries (tooth profile geometries) on meshing efficiency was examined along with evaluating the side effects on strength and noise. The effect of hypoid gear macro geometries and micro geometries on friction loss was also investigated. Consequently, the spiral angle, pinion offset and face width were mainly optimized for high efficiency and micro geometries were changed to maintain strength and NVH performance.