Experimental study on transmission abnormal sound based on side-band frequency analysis

The transmission abnormal sound affects the vehicle interior sound quality and subjective comfort. In order to control the transmission abnormal sound, the noise sources were explored. The transmission vibration and noise field tests were performed on the basis of theoretical guidelines. The experimental study indicates that one of frequencies of vehicle interior noise falls within the range of gear meshing frequency (GMF). And also the abnormal vibration of gear engagement displayed the characteristics of sideband frequency, which caused the failure of fourth driving gear. With the help of disconnecting transmission, it was found that the fourth driving gear was badly worn out, which is consistent with the analysis result of sideband frequency. After replacing the worn gears in pair, the transmission abnormal sound disappeared and the gear meshing vibration reduced significantly at 1^st order GMF and 2^nd order GMF.