Design, analysis and realization of a novel magnetic harmonic gear

High performance magnetic gears are competitive with mechanical gears in terms of their torque transmission capability, and they offer significant operational benefits. Various topologies of magnetic gear have been developed, the one which is described in this paper being particularly appropriate for use in applications for which a high gear ratio is required. It is the magnetic equivalent of a mechanical harmonic gear, and can transmit ripple-free torque at a torque density of up to ~110 kNm/m³ when high energy permanent magnets are employed. The paper will describe the operating principle, design and analysis of a harmonic magnetic gear, including a dual-stage configuration which enables much higher gear ratios to be achieved. Finally, the practical realization of such a magnetic gear will be described.