Vibration and sound radiation analysis of the final drive assembly considering the gear-shaft coupling dynamics

A generalized dynamic model of driveline system is formulated that includes the coupling effect and gyroscopic moments of the propeller shaft and hypoid gear rotor assembly. Firstly, the dynamic models with only gear-shaft coupling, with only gyroscopic effect, and with both gear-shaft coupling and gyroscopic effect are analyzed and compared. The results show that the combined effects of the gear-shaft interaction and gyroscopic behavior have considerable influence on the system dynamic responses surrounding gear bending resonances, especially for the bearing responses. However, the gear out-of-phase torsional modes still dominate the gear mesh frequency response. Secondly, the influence of pinion bending moment of inertia, propeller shaft stiffness and bearing stiffness on the system dynamic responses are examined. The system responses are then applied to perform further vibration and acoustic analysis for an axle housing structure. Computational results reveal that NVH (noise, vibration, and harshness) refinement can be achieved by tuning the pinion bearing rotational stiffness and pinion bending moment of inertia for the example considered. This study provides an understanding of the interaction between hypoid gear pair and propeller shaft, and can be employed to enhance driveline system design.