MAGNETIC POSITION DETECTION DEVICE AND MAGNETIC POSITION DETECTION METHOD
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Abstract
A magnetic position detection device configured to detect a relative movement position of a magnetic encoder, which includes N-magnetic poles and S-magnetic poles arranged alternately in a moving direction, by a magnetosensitive portion as a change in direction of a magnetic field from the encoder. As the magnetosensitive portion, direction detection type magnetoresistive elements are arranged, which each have a resistance value that changes depending on a direction of an applied magnetic field. The encoder further includes non-magnetized portions arranged at boundaries between the N-magnetic poles and the S-magnetic poles so that changes through the movement of the encoder of a magnetic-field component Bs in the moving direction of the encoder and a magnetic-field component Br in a direction in which the magnetosensitive portion and the encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are approximately sinusoidal.
11 Citations
24 Claims
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1-10. -10. (canceled)
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11. A magnetic position detection device, comprising:
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a magnetic encoder comprising N-magnetic poles and S-magnetic poles alternately arranged in a moving direction; and a magnetosensitive portion configured to detect a change in magnetic field along with movement of the magnetic encoder so as to detect a position of the movement of the magnetic encoder, wherein; the magnetosensitive portion comprises direction detection type magnetoresistive elements, each having a resistance value that changes depending on a direction of an applied magnetic field; and when a magnetic-field component in the moving direction of the magnetic encoder and a magnetic-field component in a direction in which the magnetosensitive portion and the magnetic encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are Bs and Br, respectively, the magnetic encoder further comprises non-magnetized portions that are unmagnetized and are arranged at boundaries between the N-magnetic poles and the S-magnetic poles so that changes in the magnetic-field component Bs and the magnetic-field component Br through the movement of the magnetic encoder are approximately sinusoidal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A magnetic position detection method for detecting a relative movement position of a magnetic encoder, which includes N-magnetic poles and S-magnetic poles arranged alternately in a moving direction, by a magnetosensitive portion as a change in magnetic field from the magnetic encoder, the magnetic position detection method comprising:
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arranging, as the magnetosensitive portion, direction detection type magnetoresistive elements, each having a resistance value that changes depending on a direction of an applied magnetic field; and arranging, when a magnetic-field component in the moving direction of the magnetic encoder and a magnetic-field component in a direction in which the magnetosensitive portion and the magnetic encoder are opposed to each other, which are formed at a position of the magnetosensitive portion, are Bs are Br, respectively, non-magnetized portions that are unmagnetized in the magnetic encoder at boundaries between the N-magnetic poles and the S-magnetic poles so that changes in the magnetic-field component Bs and the magnetic-field component Br through the movement of the magnetic encoder are approximately sinusoidal.
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Specification