Apparatus for detecting a rotary position of a shaft

Abstract

A noncontact rotary position sensor for measuring the rotary position of a shaft includes an annular magnetic member mounted for rotation with the shaft and a Hall effect device spaced from the shaft. The annular magnetic member includes a magnetic pole pair radially oriented. The magnetic field produced radially outwardly from the annular magnetic member is monopolar. In one embodiment, the annular magnetic member is circular and produces a magnetic field having a uniform magnetic flux density around its entire circumference at equidistant locations extending radially outwardly of the annular magnetic member and the annular magnetic member is mounted eccentric with respect to the shaft. In another embodiment of the invention, an annular magnetic member is circular and produces a magnetic field having a nonuniform magnetic flux density around the circumference of the member at equidistant locations extending radially outwardly of the annular magnetic member and the annular magnetic member is mounted coaxial with respect to the shaft. As the shaft rotates, the magnetic flux density at the Hall effect device varies.

Dependencies are inferred from the claim text.