Apparatus for sensing angular positions of an object

摘要

An apparatus for sensing a position of an object is provided that may include a magnet (22) mounted for rotation about an axis and a magnetic field-sensing device (24) mounted in fixed relation to and spaced from the magnet wherein the magnet is shaped to define a distance (26) between an exterior surface of the magnet (22) and a surface of the magnetic field-sensing device whereby rotation of the magnet causes the distance to change at a rate so that a flux density distribution sensed by the magnetic field-sensing device changes at a substantially linear rate. In one aspect the magnet is configured to have a substantially elliptical shape and the magnetic field-sensing device is a Hall-effect sensor. A sensor system (40) may include a housing (42), a magnet having an exterior surface defining a radius of curvature and a shaft (44) rotatably coupled with the housing with the magnet connected to the shaft for rotation about an axis in response to an angular displacement of an object. A magnetic field-sensing device may be provided that is coupled with the housing and spaced from the magnet to define an air gap (26) there between. The air gap may change at a rate in response to rotation of the magnet so that a flux density level sensed by the magnetic field-sensing device changes at a substantially linear rate.