Torque Characteristic Analysis of Coaxial Magnetic Gear According to Fillet Parameter of Pole Piece

Coaxial magnetic gears have the advantages of high efficiency and high reliability. However, when these magnetic gears operate, a torque ripple is generated because of the difference in magnetic resistance between the pole piece and the air. The torque ripple causes noise and vibration on the coaxial magnetic gear; therefore, it must be minimized during the design process. In this study, a pole piece with fillet was proposed to reduce torque ripple. Using a finite element analysis based on two-dimensional numerical analysis, the torque performances of the coaxial magnetic gears were compared and analyzed according to the fillet parameter value of the pole piece. Torque characteristics of magnetic gears were compared according to the various gear ratios, number of poles, and magnetic gear size. Then, the result shows that the effect of the parameters varies with the gear ratio of the magnetic gears.