Rotational angle sensor
First Claim
1. A rotational angle sensor device, comprising:
- a casing;
a movable body rotatably supported by said casing, the position of said movable body being responsive to an angular displacement caused by an external object;
permanent magnet means rigidly secured to said movable body in said casing for providing a magnetic field;
core means disposed adjacent to a range of movement of said permanent magnet means, said core means including magnetically soft material;
electrical coil means including at least one coil wound about said core means;
means for detecting the rotational position of said movable body, comprising,means for applying a pulse voltage to a first terminal of said coil to saturate magnetically said core means, andmeans coupled to a second terminal of said coil for producing a rotational angle output signal indicative of the rotational position of said magnet means and therefore of said movable body based on the time between application of said pulse voltage and saturation of said core means.
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Accused Products
Abstract
A rotational angle sensor device includes a casing, a movable body rotatably supported on the casing, a permanent magnet secured to the movable body, a magnetically soft member adjacent to the permanent magnet, and an electrical coil wound on the magnetically soft member. The movable body is responsive to a rotational angle or angular displacement caused by an external object, in response to which the permanent magnet moves in relation to the magnetically soft member, causing variations in the external flux. Those variations in external flux cause corresponding variations in the time interval from the instant at which a voltage is applied to the electrical coil to the instant at which the coil current reaches a certain level. The variations in the time interval are detected to determine the rotational angle caused by the external object. The magnetically soft member is preferably formed from an amorphous magnetically soft material. Various embodiments of the rotational angle sensor device are disclosed.
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Citations
11 Claims
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1. A rotational angle sensor device, comprising:
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a casing; a movable body rotatably supported by said casing, the position of said movable body being responsive to an angular displacement caused by an external object; permanent magnet means rigidly secured to said movable body in said casing for providing a magnetic field; core means disposed adjacent to a range of movement of said permanent magnet means, said core means including magnetically soft material; electrical coil means including at least one coil wound about said core means; means for detecting the rotational position of said movable body, comprising, means for applying a pulse voltage to a first terminal of said coil to saturate magnetically said core means, and means coupled to a second terminal of said coil for producing a rotational angle output signal indicative of the rotational position of said magnet means and therefore of said movable body based on the time between application of said pulse voltage and saturation of said core means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification