Motor
First Claim
Patent Images
1. An electric motor comprising:
- a static part includes a stator;
a field magnet having a cylindrical shape;
a rotor part having the field magnet for generating a torque around a central axis with respect to the stator;
a bearing part for supporting the rotor part rotatably with respect to the static portion around the central axis;
a sensor magnet that is a substantially ring-like rare earth anisotropic magnet and magnetized in multiple poles, the sensor magnet secured on the rotor part and arranged with the field magnet coaxially; and
a sensor disposed so as to oppose the sensor magnet, for detecting the position of the sensor magnet.
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Abstract
In a motor, an sensor magnet is attached to a shaft and three hole sensors for detecting the position of the sensor magnet are mounted on a circuit board. By using neodymium-iron-boron base rare earth magnet having radial anisotropy as a sensor magnet, the detection accuracy for the position of a field magnet via the sensor magnet by the hole sensor can be improved.
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Citations
14 Claims
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1. An electric motor comprising:
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a static part includes a stator;
a field magnet having a cylindrical shape;
a rotor part having the field magnet for generating a torque around a central axis with respect to the stator;
a bearing part for supporting the rotor part rotatably with respect to the static portion around the central axis;
a sensor magnet that is a substantially ring-like rare earth anisotropic magnet and magnetized in multiple poles, the sensor magnet secured on the rotor part and arranged with the field magnet coaxially; and
a sensor disposed so as to oppose the sensor magnet, for detecting the position of the sensor magnet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification