Abstract
The drive-system noises of motor vehicles are composed of electric apparatus noise and mechanical gear noise. In recent years, the drive-system noise generating from the motor vehicles on the narrow gauge are decreased by adoption of the low noise traction motor. However, the sound of gear noise is increased relatively. The purpose of this paper is to investigate the fundamental noise characteristics of the vehicle gear systems. Therefore, we carried out the mechanical dynamic behavior analysis to parallel cardan driving gear device which consists of helical pinion and gear systems. Furthermore, we carried out FEM and BEM analysis to predict the sound power reductions of gear systems under a condition where the casting iron material applied to the device using the damping factor obtained from simple damping test. Consequently, in case of comparing with current one, we found that the gear case which apply to the material has decreased 2dB of sound power approximately.
