Transmission error has been well known as the main source of excitation about transmission gear whine noise. To minimize transmission error in the gear system, various analysis methods have been studied and applied for long time. Many researchers were focused on gear micro geometry to achieve the low level of transmission error. But, if the gear is misaligned by several factors such as clearance and manufacturing tolerance error, then the gear noise can rapidly and unexpectedly be increased.
To overcome this problem, this new analysis method has been developed and introduced.
A transmission system simulation model was constructed, which considers various factors of transmission components such as clearance, stiffness and so on. The deformation and vibration characteristics of finite element models were validated by making comparison with frequency response function experiment.
Through the Placket-Burman screening method, the lead slope was found out one of the most sensitive factor for the transmission error. Full factorial combination analysis for the lead slope was performed under the various driving conditions. As a result, the transmission error distribution map according to the gear tooth modifications and various torque conditions was introduced. The transmission error map proposed by this analysis could make it easy to find the correction of gear micro geometry which is robust to noise.
After all, vibration distribution of new planetary gear could result in 5dB reduction compared to former transmission. Hyundai-Motors 8 speed automatic transmission was developed successfully by using this new analysis method.