Rotation detection sensor
First Claim
1. A rotation detection sensor for detecting a rotational direction of a rotating body having a gear with a tooth moving with rotation of the rotating body, the rotation detection sensor comprising:
- a magnet configured to produce a magnetic field directed to the tooth of the gear, the magnetic field varying with movement of the tooth;
a plurality of magnetic sensors located between the gear and the magnet and aligned along an imaginary straight line perpendicular to a magnetic center axis of the magnet, the plurality of magnetic sensors outputtinga plurality of sensor signals shifted in phase from each other, each sensor signal having a voltage or current value that changes depending on the magnetic field;
a rotational position detection circuit configured to receive the sensor signals from at least two of the plurality of magnetic sensors, the rotational position detection circuit performing a differential operation on the received sensor signals to output a position signal indicating a rotational position of the rotating body; and
a rotational direction detection circuit configured to receive the sensor signal from at least one of the at least two magnetic sensors, the rotational direction detection circuit outputting a direction signal, indicating a rotational direction of the rotating body, based on the position signal and the received sensor signal.
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Accused Products
Abstract
A rotation detection sensor for detecting both rotational position and direction of a rotating body with a gear includes a magnet, multiple magnetic sensors, a rotational position detection circuit, and a rotational direction detection circuit. The magnet produces a magnetic field directed to a gear tooth of the rotating body. When the rotating body rotates, the magnetic sensors output sensor signals shifted in phase from each other. The rotational position detection circuit performs a differential operation on the sensor signals received from at least two magnetic sensors and outputs a rotational position signal. The rotational direction detection circuit outputs a rotational direction signal based on the position signal and the sensor signal received from at least one of the at least two magnetic sensors.
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Citations
7 Claims
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1. A rotation detection sensor for detecting a rotational direction of a rotating body having a gear with a tooth moving with rotation of the rotating body, the rotation detection sensor comprising:
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a magnet configured to produce a magnetic field directed to the tooth of the gear, the magnetic field varying with movement of the tooth; a plurality of magnetic sensors located between the gear and the magnet and aligned along an imaginary straight line perpendicular to a magnetic center axis of the magnet, the plurality of magnetic sensors outputting a plurality of sensor signals shifted in phase from each other, each sensor signal having a voltage or current value that changes depending on the magnetic field; a rotational position detection circuit configured to receive the sensor signals from at least two of the plurality of magnetic sensors, the rotational position detection circuit performing a differential operation on the received sensor signals to output a position signal indicating a rotational position of the rotating body; and a rotational direction detection circuit configured to receive the sensor signal from at least one of the at least two magnetic sensors, the rotational direction detection circuit outputting a direction signal, indicating a rotational direction of the rotating body, based on the position signal and the received sensor signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification