Noise and Vibration Reduction Method for Electric Drivetrain System under Multiple Excitation Resources

Due to the lack of masking effect from the engine, noise and vibration from the drivetrain system have become a critical issue in electric vehicles. To address this problem, this study aims at proposing a comprehensive optimization method with respect to multiple internal excitation sources to reduce the noise and vibration of the electric drivetrain system (EDS). A rigid-flexible coupling dynamic (RFCD) model is first proposed by incorporating the elements of electric motors, gear pairs, bearings, shafts, and housing. Based on the proposed model, optimizations concerning multiple internal excitations are carried out by designing the notch width of the stator core and optimizing the modification parameters of the tooth surface along the flank and lead direction. Meanwhile, multiple operating conditions are considered in the optimization of the tooth surface to cover a complete working condition of the EDS. The results show that the torque ripple of the electric motor and the transmission error (TE) fluctuation of the gear pair is effectively reduced. Besides, the dynamic vibrations on the gearbox housing are also significantly decreased, which verifies the validity of the proposed optimization method. Then, focusing on the resonance phenomenon on the housing, a strengthened design by adding reinforced ribs in critical positions is developed to reduce the resonance vibration. At last, an experiment test is performed to verify the validity of the proposed method. In general, this study proposes a comprehensive noise and vibration reduction method for EDS, which can shed light upon the design of EDS with lower noise and vibration for engineers.