Performance of Halbach Cycloidal Magnetic Gears with Respect to Torque Density and Gear Ratio

Abstract

This paper investigates the volumetric torque density performance of a radial and an axial cycloidal magnetic gear when using a Halbach magnet rotor typology. The analysis is conducted in order to determine the geometric design rules that yield the highest volumetric torque density. The performance is studied with respect to pole-pair number, orbit length as well as the permanent magnet thickness and pole-pitch. Several parameter design guidelines are presented and shown to be valid regardless of gear ratio. Using 3-D finite element analysis a calculated torque density of up to 463 N.m/L and 475 N.m/L is shown to be achievable for the radial and axial cycloidal magnetic gear typology. The problems with unbalanced radial forces within both the radial and axial cycloidal magnetic gear is highlighted.