Effect of Compound Asymmetric Gearing on Dynamics of Gear Transmission

The fast-growing automotive industry and rapid development of new E-drive technology nowadays brings about higher gear design requirements. E-motor applications challenge gear performance due to their higher load and speed levels compared to traditional internal combustion engines (ICE). The advantages of using asymmetric gears include lower stress, higher efficiency, better bending and contact strength, increased durability, etc. However, asymmetric gear dynamics are not well understood or analyzed. This paper performs extensive study on the effect of asymmetric gears on NVH performance of compound gear transmissions. The parametric study covers different combinations of pressure angles and root fillet settings on the drive and coast sides of the gear. The analysis is focused on the sensitivity of gear transmission error (TE) towards different symmetric and asymmetric gear designs. On the system level, the influence of asymmetric gearing on the line-of-action (LOA) and effective mesh stiffness is investigated and compared with symmetric design. Finally, this study aims at providing an effective method of asymmetric gear design optimization for automotive applications in view of noise and vibration characteristics.