Analyses and experimental validation of coaxial magnetic planetary gear

Gears are widely used to transmit torque between shafts of mechanisms with corresponding changing in rotational speed and torque. The most commonly used mechanical gears have several drawbacks that limit their usage. Amongst them are low reliability, high maintenance requirements and acoustic noise. Due to these peculiarities of the traditional mechanical gears, recently magnetic gears have drawn a lot of attention. Magnetic gears have no mechanical contact between input and output shafts. Thus, they have improved reliability, high efficiency and do not require lubrication. This paper presents review of different topologies of magnetic gears. It also includes analyses and testing of a coaxial magnetic planetary gear prototype having power of about 500 W and gear ratio of 11.5. The calculations are done by numerical simulation software EasyMAG 3D based on spatial integral equation method and developed in Moscow Power Engineering Institute. The simulation results are validated by the experiments that are also presented in the paper. The article shows that coaxial magnetic planetary gears are devoid of the disadvantages of mechanical ones and have high efficiency, torque density and built-in overload protection. The main contribution of this paper is implementation of spatial integral equation method for analyses of coaxial magnetic planetary gear and description of testing procedure that was not covered in previous papers.