Design and Analysis of an Axial Flux Coaxial Magnetic Gear with Balanced Axial Forces for Precision Aerospace Actuation Application

Magnetic gears offer an alternate technology that can overcome conventional gear reliability constraints at the expense of reduced torsional stiffness for aerospace actuation applications. Certain aerospace applications require actuators to achieve a “pancake” form factor to achieve optimal system arrangements. In this manuscript, a review of axial flux magnetic gear prototypes in the known literature is presented. Additionally, as the axial flux magnetic gear is part of a larger multi-stage gear motor, the axial flux magnetic gear is designed to minimize impact on the surrounding system by minimizing leakage flux and structural requirements to withstand axial forces. To ascertain a high performance design which has minimal axial forces and leakage flux, an extensive parametric study using 3D finite element analysis (FEA) is executed. The results reveal that, when the system is considered as a whole, the pole count is one of the most important parameters to investigate. An axial flux magnetic gear design with balanced modulator axial forces is given and a detailed modulator force analysis is presented. A technology demonstrator was fabricated.