Tuning axle whine characteristics with emphasis on gear dynamics and psychoacoustics

A combined lumped parameter, finite element (FE) and boundary element (BE) model is developed to predict the whine noise from rear axle. The hypoid geared rotor system, including the gear pair, shafts, bearings, engine and load, is represented by a lumped parameter model, in which the dynamic coupling between the engaging gear pair is represented by a gear mesh model condensed from the loaded tooth contact analysis results. The lumped parameter model gives the dynamic bearing forces, and the noise radiated by the gearbox housing vibration due to the dynamic bearing force excitations is calculated using a coupled FE-BE approach. Based on the predicted noise, a new procedure is proposed to tune basic rear axle design parameters for better sound quality purpose. To illustrate the salient features of the proposed method, the whine noise from an example rear axle is predicted and tuned. The noise prediction results indicate that the spectral components of the calculated noise are mainly caused by the gear out of phase modes and the housing structure modes. The simulation results also indicate that the loudness and sharpness of the noise radiated by the rear axle can be tuned and suppressed as gear rotor system dynamic parameters are properly modified.