Angular position detection device having linear output characteristics
First Claim
1. An angular position detection device comprising a magnet device for generating a magnetic field and a magnetism detection device disposed in the magnetic field for detecting magnetism, one of said magnet device and said magnetism detection device being installed in a stator and the other being installed in a rotor, so that an angular position of said rotor is detected based on an output from said magnetism detection device, wherein said stator or said rotor in which said magnet device is installed is configured so that an intensity distribution of the magnetic field is asymmetric with respect to a center of rotation of said rotor, and wherein said stator and said rotor are configured so that an air gap between them varies gradually in a circumferential direction.
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Abstract
An angular position detection device has a rotor that comprises two magnets and a primary yoke, and a stator that comprises a pair of auxiliary yokes and a magnetism detection element. The rotor is fixed to a rotary shaft of an object to be detected. The primary yoke forms a magnetic circuit in a ring, and the magnets are configured so that the intensity distribution of the magnetic field is asymmetric with respect to the center of rotation of the rotor. The magnetism detection element is placed in a gap between the auxiliary yokes. This stator is disposed in the inside of the rotor so that an air gap between the rotor and the stator varies gradually in the circumferential direction. Thus, the magnetism detection element is enabled to produce a linear output over a range wider than 180°.
26 Citations
11 Claims
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1. An angular position detection device comprising a magnet device for generating a magnetic field and a magnetism detection device disposed in the magnetic field for detecting magnetism, one of said magnet device and said magnetism detection device being installed in a stator and the other being installed in a rotor, so that an angular position of said rotor is detected based on an output from said magnetism detection device,
wherein said stator or said rotor in which said magnet device is installed is configured so that an intensity distribution of the magnetic field is asymmetric with respect to a center of rotation of said rotor, and wherein said stator and said rotor are configured so that an air gap between them varies gradually in a circumferential direction.
Specification