Analysis of the Vibration Characteristics of Coaxial Magnetic Gear

This paper investigates the vibration and noise characteristics of the coaxial magnetic gear (CMG) by the electromagnetic forces. In the CMG, the vibration and noise can be generated by the exciting forces acting on three parts, namely, low-speed rotor, high-speed rotor, and modulating pieces, respectively. The electromagnetic forces acting on three parts of the CMG and their force frequencies are calculated by using the Maxwell stress tensor method. Also, the mode shapes of the CMG full model and their resonance frequencies are obtained by the modal analysis. Through the electromagnetic forces and the result of the modal analysis, the vibration calculation is performed by using the 3-D-finite element method. Then, the effect of displacement on noise is confirmed by comparing the vibration calculation data and experiment data. The result shows the most affected part among the three parts of the CMG due to the noise is the low-speed rotor.