Optimizing Design of Magnetic Planetary Gearbox for Reduction of Cogging Torque

Compared with the conventional mechanical gears, magnetic gears have some advantages such as low mechanical loss, maintenance-free operation and inherent overload protection. However, the interaction among the permanent magnets on the each part can inevitably produce cogging torque and torque ripple, which may cause noise and vibration. In this paper, a new design method to reduce the cogging torque is presented for the magnetic planetary gearbox. In order to achieve the goal of minimizing the cogging torque and maximizing the transmission efficiency, a global optimization algorithm and the finite element analysis (FEA) are integrated to obtain the best pole arc combination. In the process of size optimization, two optimization methods, single parameter independent optimization and Quasi Newton optimization, are applied respectively. The investigation results indicate that by using the two kinds of optimization algorithm, the cogging torque and torque ripple can be reduced significantly while the transmission efficiency can be greatly improved.