車載モータ静音化のための音圧に基づくロータバランスの試み

抄録

This paper describes a confirmation of noise reduction by rotor balance of automotive motors. Rotor balances were executed in a high-speed dynamic balance (HDB) test equipped with a bush bearing and a ball bearing of the target motor. Firstly, the bearing stiffnesses were identified from the critical speed map comparing with measurement natural frequencies of the rotor. Using the identified bearing stiffnesses, the critical speed and natural vibration modes were calculated and verified by the impact testing. The correction plane for HDB is determined by the first eigen mode obtained by the calculation. Secondly, the noise levels of the target motor were measured using the rotor balance based on the 4-Run method. The effect vector was obtained using the bearing dynamic load or the sound pressure at operating the target motor. By evaluating acoustic response, instead of commonly used bearing vibration, the noise levels of the target motor were finally able to reduce by max 9 dB.