| 摘要 |
PROBLEM TO BE SOLVED: To make an electric motor generate brake force for input of an external force through a simple structure. SOLUTION: An auxiliary magnet 7 is juxtaposed axially to a permanent magnet 6 enclosing a rotor 5. Circumferential length of the rotor in the auxiliary magnet is set slightly longer than the circumferential width of one tooth but shorter than the width between the opposite outer ends of two teeth. The auxiliary magnet is disposed while being shifted by a predetermined swing angle from the circumferential central position of the permanent magnet. Since a part of a plurality of teeth is in magnetically coupled state with the auxiliary magnet under suspension of a motor, the rotor can be held at a stop position. Consequently, a brake force can be generated for input of an external force through a simple structure of providing an auxiliary magnet. With such an arrangement structure, a large cogging torque becoming a brake force is generated and torque ripple can be reduced. COPYRIGHT: (C)2007,JPO&INPIT
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