Tolerance-Insensitive Design of the Magnet Shape for a Surface Permanent Magnet Synchronous Motor

Many studies have been conducted to reduce the cogging torque of electric power steering motors. However, in the mass production of such motors, it is essential to enhance performance robustness in relation to tolerances. For such motors, this work analyzes performance robustness in relation to tolerances by applying a cycloid curve to the surface magnet of the rotor. Applying a cycloid curve to the magnet surface of the rotor is one of several ways to reduce cogging torque. To evaluate the performance of the cycloid curve, we compare it with an eccentric curve. The two curves are compared for the same specifications and evaluated using the indicator, tolerance insensitivity rate, which is used to assess performance robustness in relation to tolerances. The cycloid curve was evaluated to be more robust in relation to tolerances, as compared with the eccentric curve. Finally, an experiment was conducted to validate the robustness of the cycloid curve.

Microstructure of magnetic field on permanent magnet surface

In this case we investigate the NdFeB permanent magnet by the atomic force microscopy. Obtained phase diagrams in the center and on the edge of the sample. We investigate the uniformity of the magnetic structure.

Research on Bonded NdFeB Arc-Magnets

The manufacture technology and mould structure of bonded NdFeB arc-magnets from press molding were described. The effects of the content of binder and additives, particle size of magnetic powder, the molding pressure, the treatment of magnet surface on the mechanical property, processing property, magnetic property and anti-oxidation property of press molding magnets were investigated. The press molding bonded magnets were prepared by using the MQP-B rapidly quenching NdFeB magnetic powder and epoxy binder. The magnetic properties are: Br = 0.722 T, Hcb = 457 kA/m, Hci = 718 kA/m, and (BH) max = 83.5 kJ/m3.

Research on Composite Powder and Magnet Properties of Bonded NdFeB Magnets Prepared by Press Molding

The manufacture technology and properties testing method of composite powder and bonded NdFeB magnets from press molding were described in detail. The effects of the content of binder and additives, the molding pressure, the treatment of magnet surface on the mechanical property, processing property, magnetic property and anti-oxidation property of press molding magnets were investigated. Furthermore, the effect mechanism was revealed microcosmically. The press molding bonded magnets was prepared by using the MQP-B rapidly quenching NdFeB magnetic powder and epoxy binder. The magnetic properties are: Br = 0.722 T, Hcb = 457 kA/m, Hci = 718 kA/m, and (BH) max = 83.5 kJ/m3.