Hall effect position sensor with flux limiter and magnetic dispersion means

摘要

A low cost Hall effect position sensor is disclosed which includes a Hall effect integrated circuit disposed in close proximity to a metallic target device. The Hall device is mounted on a flanged flux dispersion pole piece. The opposite end of the pole piece is attached to a rare earth or Alnico magnet. The flanged magnetic flux dispersion pole piece is designed to disperse a highly concentrated magnetic flux field from a magnet, typically an Alnico or rare earth magnet, into a low intensity magnetic flux field which is compatible with the Hall effect device as well as constant and evenly dispersed across the face of the flanged pole piece. The area of the dispersion flange face is designed so measured magnetic field in an air gap between the dispersion pole piece and a ferrous target is increased by a factor of 3 when compared to an open circuit field intensity field measurement at the surface of the dispersion pole piece. The open circuit field intensity of the sensor is below the release point of the Hall effect device. When a metallic body or ferrous target is near, the flux at the face of the dispersion pole piece is increased above the operate point of the Hall device and the digital Hall device is activated or "turned on". The dispersion flanged pole piece, the magnet and the Hall device function as an accurate low cost position sensor.