Linear position sensor having a permanent magnet that is shaped and magnetized to have a flux field providing a sensor output that varies linearly between opposite end points of relative linear movement between the magnet and sensor
First Claim
1. A sensor system for measuring linear displacement of a first member relative to a second member in a linear direction of relative movement comprising:
- an analogue Hall Effect sensor secured to the first member in an orientation to sense magnetic flux in a sensing direction perpendicular to said direction of relative movement, a permanent magnet secured to the second member and having a front surface that faces the Hall Effect sensor and extends along the direction of relative movement between the first and second members, the permanent magnet having opposite ends spaced-apart in said direction of relative movement, the permanent magnet being magnetized to have a magnetic pole of one magnetic polarity on said front surface adjacent one of said opposite ends and a second magnetic pole of an opposite magnetic polarity on said front surface adjacent the other of said opposite ends.
1 Assignment
0 Petitions
Accused Products
Abstract
A sensor system for measuring linear displacement of a first member relative to a second member, includes an analogue Hall Effect sensor secured to the first member in an orientation to sense magnetic flux in a sensing direction perpendicular to said direction of relative movement, and a permanent magnet secured to the second member and having a front surface facing the Hall Effect sensor and extending along the direction of relative movement between the first and second members. The permanent magnet is magnetized so that the front surface has a first magnetic pole of a first magnetic polarity at a first end and a second magnetic pole of a second magnetic polarity at a second end spaced from the first end in the direction of travel.
-
Citations
23 Claims
-
1. A sensor system for measuring linear displacement of a first member relative to a second member in a linear direction of relative movement comprising:
an analogue Hall Effect sensor secured to the first member in an orientation to sense magnetic flux in a sensing direction perpendicular to said direction of relative movement, a permanent magnet secured to the second member and having a front surface that faces the Hall Effect sensor and extends along the direction of relative movement between the first and second members, the permanent magnet having opposite ends spaced-apart in said direction of relative movement, the permanent magnet being magnetized to have a magnetic pole of one magnetic polarity on said front surface adjacent one of said opposite ends and a second magnetic pole of an opposite magnetic polarity on said front surface adjacent the other of said opposite ends. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- 13. In a position sensing device including a permanent magnet and a sensor relatively movable parallel to one another, said magnet having opposite ends and a length between said opposite ends in the direction of relative movement between said magnet and sensor, said magnet having a front face that faces toward said sensor, said magnet being magnetized to provide magnetic flux extending outwardly from said front face that includes at least three flux fields providing sensor responsive flux to which said sensor responds, and said magnetic flux providing sensor responsive flux in said at least three flux fields with a density that varies substantially linearly along said length of said magnet.
-
16. In a position sensing device including a permanent magnet and a sensor relatively movable parallel to one another, said magnet having opposite ends and a length between said opposite ends in the direction of relative movement between said magnet and sensor, said magnet having a front face that faces toward said sensor, said magnet being magnetized to provide at least three flux fields extending outwardly from said front face along said length and to which said sensor responds, and said at least three magnetic flux fields being shaped to provide said sensor with an output that varies substantially linearly along said length of said magnet.
- 17. A permanent magnet having front and rear faces and opposite ends, a thickness dimension between said front and rear faces, and a length between said opposite ends, said magnet being magnetized in the direction of said thickness dimension to provide magnetic poles on said front and rear faces, said magnetic poles being positioned and having a polarity to provide at least three different flux fields extending outwardly from said front face along said length.
- 22. A permanent magnet having opposite front and rear faces, opposite ends, and a midpoint that is midway between said opposite ends, said magnet being magnetized to have a north magnetic pole on said rear face and a south magnetic pole on said front face between said midpoint and one of said ends and to have a south magnetic pole on said rear face and a north magnetic pole on said front face between said midpoint and the other of said ends, said poles providing end flux fields of opposite polarity that extend outwardly of said ends between end surface portions of said front and rear faces, and said poles providing intermediate flux fields that extend outwardly from said front and rear faces across said midpoint between intermediate portions of said front and rear faces located on opposite sides of said midpoint.
Specification