Preliminary Analysis for Two-Degree-of-Freedom Magnetic Geared Screw Motor with High Torque Density

The paper proposes a two-degree-of-freedom (2-DOF) magnetic geared screw motor. As a 2-DOF motor that generates the large thrust force, a radial-gap 2-DOF motor based on a magnetic screw structure has been proposed. The radial-gap 2-DOF motor comprises a mover part, which corresponds to a screw part of the magnetic screw, two rotor parts, which are nut parts of the magnetic screw, and two stator parts. It can generate a torque around the central axis and a thrust force along the central axis independently in the mover part. Especially, a large thrust force is generated because of the magnetic screw structure. In order to improve not only the thrust force but also the torque of the radial-gap 2-DOF motor, the paper proposes the 2-DOF magnetic geared screw motor. The 2-DOF magnetic geared screw motor is the radial-gap 2-DOF motor with which the magnetic geared screw is integrated. A magnetic gear and a magnetic screw are implemented between the rotor parts and the mover part. The paper describes the structure of the 2-DOF magnetic geared screw motor and the magnetic geared screw implemented in the 2-DOF motor. Additionally, it indicates the effectiveness of the proposed magnetic geared screw with analysis results.