Prediction of the vibroacoustic response of an electric window-lift gear motor

A numerical approach is proposed for analyzing the vibroacoustic behavior of an electric window-lift gear motor and differentiating the different excitation sources. These ones correspond to the normal electromagnetic forces applied to steel stator, the electromagnetic input torque fluctuation, the rotor mechanical imbalance, the worm gear static transmission error and mesh stiffness fluctuations and the gear wheel eccentricity. The computing of the vibroacoustic response is performed using an iterative spectral method. Spectrograms of the dynamic response show components corresponding to the harmonics of the excitation spectra as well as a frequency enrichment generated by the coupling between the mesh stiffness fluctuation and the other driveline excitation sources. Finally, the contributions of the different excitation sources to the spatial average of the mean square velocity of the radiating surface and the equivalent global dynamic force transmitted to the supporting structure are compared.