Measurement and Torque Calculation of Magnetic Spur Gear Based on Quasi 3-D Analytical Method

This paper presents the torque characteristics analysis and torque measurement of a magnetic spur gear with a three-segment Halbach array based on the Quasi Three-Dimension (3-D) Analytical Method. It analyzes a magnetic spur gear that uses a Halbach array by employing an analytical method for torque calculation. In the analytical method, from the magnetic vector potential and a coordinate system conversion, analytical solutions are obtained for magnetic fields produced by source magnets. By using the derived magnetic field solutions, an analytical solution is obtained for the external magnetic flux density. The drive magnet is next reduced to the equivalent current densities, and the torque is computed from these currents in the external magnetic field, which is obtained from the second process. Finally, the leakage flux in the z-direction occurring in the magnetic gear is considered using the 3-D analytical method. Thus, an analytical result can be obtained. These results are validated by comparison with the finite element method.