| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor which delivers high output, and is inexpensive and is small-sized by forming a rotor out of a cylindrical permanent magnet portion with at least its circumferential surface being divided in the circumferential direction and alternately magnetized in different poles. SOLUTION: The outside surface of a cylindrical magnet 1 constituting the permanent magnet portion of a rotor is circumferentially divided into (n) areas, which are in turn alternately magnetized in south poles and north poles. Then coils are arranged in the direction of the axis of the magnet 1, and the outer magnetic poles 18a and 18b and inner magnetic poles 18c and 18d of a stator 18 excited by the coils are made to face the circumferential surface and inner circumferential surface of the magnet 1. A cover is provided with a permanent magnet, which holds the centers K1, K2, K3, and K4 of the poles of the magnet 1 at positions which are off the straight line connecting the centers Q1 and Q2 of the outer magnetic poles 18a and 18b and the rotational center Q3 of the magnet 1, when the coils are not energized. As a result, force exerted on the magnet is prevented from being directed towards the rotational center of the magnet, and rotation can be started up with stability.
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