Torque Density Enhancement of Magnetic Worm-Geared Motor with Half Skew Structure by Introducing Curved Tooth Shape

Magnetic Worm-Geared Motor (MWGM) is a novel low-speed high-torque motor with an integrated magnetic worm gear for high torque density. The basic structure has been previously proposed by the authors. In the previous study, it was shown that introducing a half skew structure improved its torque density. In this paper, the cause of increased torque density is investigated from the viewpoint of the flux-linkage. It is shown that the half skew structure could double no-load flux-linkage but magnetic saturation at stator teeth worsens the ratio. Therefore, a novel curved tooth shape is proposed to suppress the magnetic saturation. Finally, 3D Finite Element Analysis (3D-FEA) is carried out to compare the performance. Analysis result shows that torque density is effectively improved.