| 摘要 |
<p>Variation in the torque of a synchronous motor used in a machine tool leaves trace of machining on the machined surface of a work, and is not desirable. Moreover, difficulty is generally involved in magnetizing the magnets (14) that are stuck to the rotor of the synchronous motor. In this invention, the magnets (20, 30) have a contour of the shape of nearly a parallelogram, and a change in the size in the lengthwise direction (X) relative to a position in the circumferential direction Υ is approximated to a sinusoidal wave. Therefore, the gap between the neighboring magnets is set to be broad, the magnetizing operation is facilitated, and a change in the torque decreases. The change in the torque can be further decreased if the gap $(1,3)$ between the magnet (20) and the inner periphery (50) of the stator is so formed as to gradually increase from the central position (P1) in the circumferential direction Υ toward both ends.</p> |
