| 摘要 |
PROBLEM TO BE SOLVED: To efficiently and easily form a strong magnetic flux distribution around a rotor. SOLUTION: The thickness of a ring magnet 2 is about 2 mm, and the diameter of a shaft 1 is about 50 mm. The thickness of an epoxy bond 3 is about 15μm (1/6 or less of conventional value). Both are bonded together, resulting in the magnetic resistance at the bonding part being 1/6 or below of conventional value. A slit 4 is provided at an intermediate point between an N-pole magnetized part and an S-pole magnetized part, with the slit 4 being almost V-shape. Thanks to this shape, a stress is effectively concentrated on a point directly under the tip of V-shape. Almost no magnetic flux leaks at the point on the outer periphery of the ring magnet where a magnetic flux density is almost zero even if a crack occurs, with little effect on the magnetic flux distribution. So, if the slit is provided to such part as the magnetic flux density is almost zero, the part that can cause cracking is limited to the slit position, and no output torque is dropped nor cogging torque is increased even when a cracking occurs. COPYRIGHT: (C)2004,JPO
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