Abstract
Quieter transmissions in modern automotive vehicles had become an overwhelming priority. Gear noise is a major contributor to the overall transmission noise. Noise measurements involve high cost equipment and testing conditions. In many scenarios, it is very challenging to the noise engineer to come up with design directions for resolving noise issues. In this work Multibody Dynamics (MBD) analysis approach is used considering gear contact definition with static transmission error. Transmission error is calculated using Load Distribution Program (LDP) incorporating gear micro geometry variation as excitation. Dynamic bearing loads are calculated at the interface of transmission housing for given loading and speed sweep. The calculated loads are applied on the FE system level transmission model. FE model includes lumped mass and inertia of transmission non-structural components of transmission along with transmission housing. This model is used to identify critical noise paths by considering calculated acceleration on housing as a noise metric. The system model is validated with transmission noise test measured sound power correlation with pseudo sound power calculated with mass compensated FE model using ABAQUS. Stiffening/softening the critical noise paths and hot spot regions on the housing are used to minimize noise by avoiding the resonance. A unique process flow is proposed to mitigate gear noise issues at the early stage of design.