| 摘要 |
PROBLEM TO BE SOLVED: To allow reduction in cogging torque, that is hard to demagnetize, and to allow improvement in the drive torque, being useful for higher performance and smaller size of an AC servo permanent magnet motor, DC brusshless permanent magnet motor, and the like, for high utilization in industrial application. SOLUTION: The permanent magnet, having a D-shape cross section, comprises an arc-like top face, a flat bottom face, and both side faces. When a plurality of D-type permanent magnets are arranged in the circumferential direction so as to penetrate the tip at the center of the top surface of each magnet, drawing a vertical large circle, the outside profile at the center of the top surface of the permanent magnet coincides with the arc of a virtual small circle, whose center of outer diameter is so deviated as to be smaller than the outside diameter of the virtual large circle; at the same time, each upper edge at both ends in the width direction of the arc-like top surface is located closer to the virtual large circle, beyond the intersection between the virtual small circle and both side surfaces of the magnet, which will not go over intersection between the virtual large circle and both side surfaces of the magnet. COPYRIGHT: (C)2008,JPO&INPIT
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