Non-Contacting Position Sensor Using a Rotating Magnetic Vector

Abstract

A sensor for sensing the position of an object includes a magnet and a magnetic flux sensor. The magnet has dimensions that include a length, a width and a height. The magnet is adapted to generate a flux field. The flux field has a magnitude of flux and a flux direction. The flux direction changes along at least one of the dimensions. The magnetic flux sensor is mounted adjacent the magnet. The magnet provides a rotating magnetic field vector. A method for magnetizing a magnet to create the rotating magnetic field vector is also disclosed.

1 . A sensor comprising:
 a) a magnet having a first, second, third, fourth, fifth and sixth surface;   b) the magnet being adapted to generate a flux vector within the magnet, the flux vector having a magnitude of flux and a flux direction; and   c) the flux direction within the magnet being co-planar with the first and second surfaces and changing a plurality of times along the third surface.   
     
     
         2 . The sensor of  claim 1 , wherein the flux direction changes in increments less than ninety degrees. 
     
     
         3 . The sensor of  claim 1 , wherein the flux vector comprises at least two orthogonal components. 
     
     
         4 . The sensor of  claim 1 , wherein a magnetic flux sensor is mounted adjacent the magnet, the magnetic flux sensor being adapted to sense the flux direction. 
     
     
         5 . The sensor of  claim 4 , wherein the magnetic flux sensor is insensitive to temperature changes in the magnet. 
     
     
         6 . The sensor of  claim 4 , wherein the magnetic flux sensor is insensitive to amplitude related variations. 
     
     
         7 . The sensor of  claim 4 , wherein the magnetic flux sensor comprises a Hall effect device. 
     
     
         8 . The sensor of  claim 4 , wherein the magnet is affixed to a movable object such that when the object moves the magnet moves relative to the magnetic flux sensor.