Design and Analysis of a Double Coaxial Magnetic Coupling to Improve Torque Density

Coaxial magnetic couplings are an attractive alternative to traditional mechanical machine couplings which bring several desirable advantages but are limited by their relatively low torque density and torque to mass ratio. The optimum magnetic design of a coaxial magnetic coupling possesses a significant volume of inactive material due to the radius of the permanent magnet arrays. In this paper, the torque density of a coaxial magnetic coupling is increased by up to 82% by utilizing a second set of permanent magnet rings to form a double coaxial magnetic coupling. The proposed design enhancement achieves the aim of reducing the total volume of the coupling, whilst maintaining the same mass and peak torque transmission capacity.