基于EMI技术的小型直流电机振动噪声研究

Research on Vibration Noise of Small DC Motors based on EMI Technology

针对某型高档轿车用于座椅调节的小型直流电机工作时出现的振动噪声问题,探索一种准确有效且受环境因素影响小的方法,找到振动噪声产生的原因并确定解决方案。首先对电机进行声压实验以及压电阻抗实验,通过对比发现压电阻抗技术在振动噪声分析方面的优异性;结合测得的电机阻抗有效峰值频率,划分共振区,确定产生振动噪声的原因是定子和转子在8kHz处存在同频共振;基于改变定子机壳厚度和添加辐条2种优化方案对电机进行有限元仿真,结果显示有效峰值频率与机壳厚度、辐条数存在一定的变化关系;最后结合压电阻抗技术,用2种不同厚度的辐条对电机进行阻抗实验,验证了添加辐条方案的有效性,可为有效规避小型直流电机振动噪声的研究提供参考。

The vibration and noise problem of small DC motors for high grade car seat adjustment is studied. The solution method, which is accurate, effective and less affected by environmental factors, is proposed. Firstly, the acoustic pressure and piezoelectric impedance experiments are carried out for the motor, and the superiority of the piezoelectric impedance technology in vibration and noise test is found by comparison. According to the measured effective peak frequency of the motor impedance, the resonance region is determined. It is confirmed that the reason of vibration and noise is the resonance between the stator and the rotor at 8 kHz frequency. Then, two improvement strategies, changing the thickness of the stator shell and adding spokes to the rotor, are proposed for the motor and the finite element simulation is carried out. The relationship of the effective peak frequency with the thickness of the shell and the number of spokes is obtained. Finally, using piezoelectric impedance technology, the experiments of the motor with two different thickness spokes are carried out, the scheme of adding spokes is verified effective. Result of the study is helpful for the research of small DC motors to effectively avoid vibration and noise.