Electromagnetic shaft position sensor and method
First Claim
1. A rotational position sensing system, comprising:
- a rotor having at least an outer surface;
a stator having at least an inner surface and surrounding at least a portion of the rotor outer surface, the stator inner surface spaced-apart from the rotor outer surface to form a gap therebetween;
one or more magnets coupled to, and circumscribing at least a section of, one of the rotor outer surface and the stator inner surface, to thereby generate a magnetic field in the gap; and
at least two magnetic field sensors disposed at least partially in the gap and positioned at a predetermined angle relative to one another.
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Accused Products
Abstract
A rotational position sensing system includes a rotor, one or more magnets, a stators and at least two magnetic field sensors. The stator has an inner surface and surrounds at least a portion of an outer surface of the rotor. The stator inner surface is spaced-apart from the rotor outer surface to form a gap therebetween. The magnets are coupled to, and circumscribe at least a section of, either the rotor outer surface or the stator inner surface. The magnetic field sensors are disposed at least partially in the gap and are positioned at a predetermined angle relative to one another. The sensors detect variations in magnetic field flux as the rotor and stator rotate relative to one another and supply signals that are processed to determine the rotational position of the rotor relative to the stator.
32 Citations
26 Claims
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1. A rotational position sensing system, comprising:
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a rotor having at least an outer surface;
a stator having at least an inner surface and surrounding at least a portion of the rotor outer surface, the stator inner surface spaced-apart from the rotor outer surface to form a gap therebetween;
one or more magnets coupled to, and circumscribing at least a section of, one of the rotor outer surface and the stator inner surface, to thereby generate a magnetic field in the gap; and
at least two magnetic field sensors disposed at least partially in the gap and positioned at a predetermined angle relative to one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A rotational position sensing system, comprising:
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a rotor having at least an outer surface;
a stator having at least an inner surface and surrounding at a portion of the rotor outer surface, the stator inner surface spaced-apart from the rotor outer surface to form a gap therebetween;
a permanent magnet coupled to, and circumscribing at least a section of, one of the rotor outer surface and the stator inner surface, the permanent magnet being magnetized across its diameter and generating a magnetic field in the gap; and
at least two magnetic field sensors disposed at least partially in the gap and positioned at a predetermined angle relative to one another. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of determining a rotational position of a first element relative to at least a second element, comprising:
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coupling one or more magnets to, and circumscribing at least a portion of, the first element, the first element configured to rotate relative to the second element;
surrounding the magnets with the second element such that it is spaced-apart from the first element to form a gap therebetween; and
sensing magnetic field flux magnitude variations at least at two positions in the gap when the first element rotates relative to the second element. - View Dependent Claims (25, 26)
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Specification