Effects of misalignment on the transmission characteristics of magnetic couplings

Abstract

Magnetic couplings possess no mechanical contact and permit higher assembly tolerance for transmitting torque from a primary driver to a follower by magnetic force. This paper investigates the effects of misalignment on the transmission characteristics of synchronous magnetic couplings. The misalignment can be categorized into the following three types: transverse, angular and a combination of these two misalignments. Without loss of generality, an axial synchronous magnetic coupling is adopted in the present because of its simplicity both in design and fabrication. The phenomenon and influence of shafts with assembly misalignment are described first. The mathematical model for the magnetic coupling with misalignment is then constructed for the purpose of deriving the equations governing the torque transmission and force interaction characteristics. The method of equivalent magnetic charge is employed to calculate the variations in the transmitted torque owing to each type of misalignment. Finally, a test apparatus is constructed for verifying the static and dynamic characteristics of the designed coupling under various misalignment conditions. Good agreement between numerical simulation and experimental results is obtained.