Position sensor utilizing a linear hall-effect sensor
AssigneeBEI Sensors & Systems Company, Inc.
InventorMikhail Godkin
Life of this patent
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Abstract
A magnetic field assembly and method of configuring the same for use in position sensors of the type which include a magnetic field sensor. First and second magnets in the field assembly are positioned on a surface of a magnetic plate (return path) and separated from one another by a separation distance. The first magnet has a magnetic axis substantially transverse to the surface of the magnetic plate, and the first magnet has a polarity opposite a polarity of the second magnet. The thicknesses of the first and second magnets are selectively varied along a stroke direction, and the separation distance is selected along with a gap length distance between the magnetic sensor and the field assembly, so that a predetermined flux density versus stroke characteristic can be provided for the position sensor.
Claims33
A magnetic field assembly for use in a position sensor device of the type which includes a magnetic field sensor and having a stroke direction, the field assembly comprising
- first and second magnets positioned on a surface of a magnetic plate and separated from one another by a separation distance, wherein the first magnet has a magnetic axis substantially transverse to the surface of the magnetic plate, and the first magnet has a polarity orientation opposite a polarity orientation of the second magnet;
- and
- further wherein cross sectional thicknesses of the first and second magnets are selectively varied along the stroke direction, the magnetic field assembly is positionable for movement relative to the magnetic field sensor at a gap length distance, and the separation distance is selected to be greater than the gap length distance, so that a predetermined flux density versus stroke characteristic can be provided for the position sensor.
A position sensor device having a stroke direction, comprising
- a magnetic field sensor;
- and
- a magnetic field assembly including first and second magnets positioned on a surface of a magnetic plate and apart from one another by a separation distance;
- wherein the first magnet has a magnetic axis substantially transverse to the surface of the magnetic plate, and the first magnet has a polarity orientation opposite a polarity orientation of the second magnet, and the magnetic field assembly is positioned for movement relative to the magnetic field sensor at a gap length distance;
- and
- further wherein the thickness of the first and second magnets is selected to vary along the direction of the stroke of the position sensor, and the gap length distance and the separation distance are selected so that the separation distance is greater than the gap length distance, so that a predetermined flux density versus stroke characteristic is provided for the position sensor.
A method for configuring a magnetic field assembly for use in a position sensor device of the type which includes a magnetic field sensor and a stroke direction, the method comprising the steps of
- positioning first and second magnets on a surface of a magnetic plate to be separated from one another by a separation distance, wherein the first magnet has a magnetic axis substantially transverse to the surface of the magnetic plate, and the first magnet has a polarity orientation opposite a polarity orientation of the second magnet;
- positioning the magnetic field assembly for movement relative to the magnetic field sensor at a gap length distance;
- and
- selectively varying the thicknesses of the first and second magnets along the stroke direction and selecting the separation distance to be greater than the gap length distance, so that a predetermined flux density versus stroke characteristic can be provided for the position sensor.
A magnetic field assembly for use in a position sensor device of the type which includes a magnetic field sensor and having a stroke direction, the field assembly comprising
- first and second magnets positioned on a surface of a component providing a magnetic return path having a cylindrical cross section and separated from one another by a separation distance, wherein the first magnet has a magnetic axis substantially transverse to the surface of the component providing the magnetic return path, and the first magnet has a polarity orientation opposite a polarity orientation of the second magnet,
- wherein the first and second magnets are ring magnets, and the component providing the magnetic return path is a magnetic ring;
- and
- further wherein cross sectional thicknesses of the first and second magnets are selectively varied along the stroke direction, and the separation distance is selected, so that a predetermined flux density versus stroke characteristic can be provided for the position sensor.
Dependencies are inferred from the claim text.