High resolution non-contacting multi-turn position sensor
First Claim
1. A device, comprising:
- a housing;
a rotatable shaft having a longitudinal axis, wherein at least a portion of the shaft is within the housing;
a movable carrier disposed substantially within the housing and coupled to the shaft such that rotation of the shaft results in linear motion of the carrier along the longitudinal axis;
a magnet having a magnetization axis and disposed on the carrier so as to move with the carrier such that a range of rotation of the shaft results in a range of linear motion of the magnet along the longitudinal axis, the magnet oriented such that the magnetization axis is substantially perpendicular to the longitudinal axis; and
a magnetic sensor circuit having a sensor element disposed relative to the magnet and substantially within the housing, the sensor element configured to sense a first flux density along the magnetization axis and a second flux density along a direction perpendicular to the magnetization axis resulting from the magnet and generate a signal based on the sensed first flux density and the second flux density, the range of linear motion of the magnet including both longitudinal sides of the sensor element such that the sensed first flux density has a maximum magnitude when the magnet is approximately aligned with the sensor element.
1 Assignment
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Accused Products
Abstract
Disclosed are systems and methods for effectively sensing rotational position of an object. In certain embodiments, a rotational position sensor can include a shaft configured to couple with the rotating object. The shaft can be configured to couple with a magnet carrier such that rotation of the shaft yields translational motion of the carrier. A magnet mounted to the carrier also moves longitudinally with respect to the axis of the shaft, and relative to a magnetic field sensor configured to detect the magnet'"'"'s longitudinal position. The detected longitudinal position can be in a range corresponding to a rotational range of the shaft, where the rotational range can be greater than one turn. In certain embodiments, the rotational position sensor can include a programmable capability to facilitate ease and flexibility in calibration and use in a wide range of applications.
52 Citations
41 Claims
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1. A device, comprising:
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a housing; a rotatable shaft having a longitudinal axis, wherein at least a portion of the shaft is within the housing; a movable carrier disposed substantially within the housing and coupled to the shaft such that rotation of the shaft results in linear motion of the carrier along the longitudinal axis; a magnet having a magnetization axis and disposed on the carrier so as to move with the carrier such that a range of rotation of the shaft results in a range of linear motion of the magnet along the longitudinal axis, the magnet oriented such that the magnetization axis is substantially perpendicular to the longitudinal axis; and a magnetic sensor circuit having a sensor element disposed relative to the magnet and substantially within the housing, the sensor element configured to sense a first flux density along the magnetization axis and a second flux density along a direction perpendicular to the magnetization axis resulting from the magnet and generate a signal based on the sensed first flux density and the second flux density, the range of linear motion of the magnet including both longitudinal sides of the sensor element such that the sensed first flux density has a maximum magnitude when the magnet is approximately aligned with the sensor element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A multi-turn rotational position sensor, comprising:
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a rotatable shaft having a longitudinal axis; a movable carrier coupled to the shaft such that rotation of the shaft results in linear motion of the carrier along the longitudinal axis; a magnet disposed on the carrier so as to move with the carrier such that N rotations of the shaft results in a range of linear motion of the magnet along the longitudinal axis, the quantity N being greater than 1; a programmable integrated circuit configured to define the N rotations of the shaft as an operating range of the rotational position sensor, the programmable integrated circuit including a magnetic sensor disposed relative to the magnet and configured to measure at least two separate directional components of a magnetic field resulting from the magnet to generate an output signal representative of a longitudinal position of the magnet relative to the magnetic sensor and thus a corresponding rotational position of the shaft within the operating range the at least two directional components including a first direction parallel with a magnetization axis of the magnet and a second direction perpendicular to the magnetization axis.
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23. A sensor for determining a rotational position of an object, comprising:
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a rotatable shaft having a longitudinal axis and configured to allow rotational coupling with the object; a sensed assembly coupled to the shaft such that rotation of the shaft results in linear motion of the sensed assembly along the longitudinal axis, the sensed assembly including a magnet; a sensor assembly disposed relative to the sensed assembly and configured to measure at least two separate directional components of a magnetic field resulting from the magnet and generate an output signal so as to allow determination of longitudinal position of the sensed assembly at a plurality of locations along the longitudinal axis the at least two directional components including a first direction parallel with a magnetization axis of the magnet and a second direction perpendicular to the magnetization axis; and a housing configured to house at least some portions of the sensed assembly, the sensor assembly, and the rotatable shaft, the housing configured to be mountable to a mounting structure, the housing dimensioned to have a curved wall, the housing further having first and second substantially straight walls extending from the ends of the curved wall so as to define a U-shape when viewed along the longitudinal axis. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A rotational position sensor, comprising:
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a housing; a rotatable shaft having a longitudinal axis, wherein at least a portion of the shaft is within the housing; a movable carrier disposed substantially within the housing and coupled to the shaft such that rotation of the shaft results in linear motion of the carrier along the longitudinal axis; and a magnet disposed on the carrier so as to move with the carrier such that a range of rotation of the shaft results in a range of linear motion of the magnet along the longitudinal axis; a magnetic sensor circuit disposed relative to the magnet and substantially within the housing, the magnetic sensor circuit configured to sense two or more separate components of a magnetic field resulting from the magnet and generate an output signal representative of a linear position of the magnet, and thus a rotational position of the shaft the two or more components of the magnetic field including a first direction parallel with a magnetization axis of the magnet and second direction perpendicular to the magnetization axis. - View Dependent Claims (38, 39, 40, 41)
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Specification