Some automobile transmissions (AT, CVT, etc.) generate a unique noise, and a soundproof material cover is attached to reduce the noise. The cover is fixed to the transmission body and reduces (sound absorbing and insulating) the sound radiated from the transmission, but the sound radiated from the cover may affect the transmission of vibrations. In this study, we attached a simple-shaped cover to a jig assuming a transmission, and measured the vibration acceleration and sound pressure level when the jig was vibrated. In addition, the jig and cover were modeled by FEM, and vibroacoustic analysis was performed. The material of the cover is felt or GW, and calculated using the Biot-allard model. We will report changes in vibration acceleration and sound pressure level when the cover fixing method and cover material are changed.
