Proposal of a radially differential type magnetic-geared motor

Purpose This paper aims to propose a new magnetic-geared motor (MGM) which can easily increase the gear ratio up to approximately several hundred. The operational principle is described, and the relationship between the maximum transmission torques of each layer of the differential harmonic magnetic gear is investigated using a mathematical model and finite element method (FEM). Design/methodology/approach The operational principle and maximum transmission torque are described using a mathematical model. The FEM is used to investigate the operational principle and torque characteristics. Findings As the proposed model can realize a larger gear ratio than the conventional model, the torque constant can be approximately 100 times as large as that of the conventional model. Research limitations/implications The proposed and conventional models have the same shape stator, and it is not optimized. Originality/value The relationship between the maximum transmission torques of each layer is described, and this helps the design of a differential type MGM.