Axle gear whine originates at the hypoid gearset, and can be amplified by the driveline system dynamics as well as the transfer paths into the vehicle. In addition to tremendous efforts in improving the gear quality, it is of some importance that optimized system dynamics be achieved so that the system sensitivity to the gear excitation can be greatly reduced. This methodology has been extensively utilized in American Axle through a combined numerical simulation (FEA) and testing approach.
This paper presents the FEA modeling techniques in studying axle system dynamics and the level of accuracy of the model that can be achieved in predicting forced system responses. The use of a driveline system model in the development of a design optimization for total system NVH performance is discussed. Examples are provided to demonstrate the effects of modal alignments and appropriate system tuning.