A method has been developed for predicting the sound radiation characteristics of transmission cases in order to reduce gear whine noise radiating from transmissions. Normal components of frequency response vectors on the transmission case surface calculated using an FE -model of the case are used to predict sound radiation characteristics. To study the validity of the method, the correlation between sound pressure level and the level of vibration of the case surface during operation and the predicted sound radiation characteristics was investigated. Results showed a good correlation between the figures and enabled equations of correlation between them unaffected by shape or type of transmission to be obtained, indicating that this method is sufficiently accurate for studying case specifications at the design stage.This method enables the design of transmission cases fulfilling performance requirements for gear whine noise using only an FE -model of the case. The employment of the method in the development process commenced with the development of 2004 model year LIFE AT.
Article of Honda R&D Technical Review Vol.17 No.1 (42 - 45)