Angular position sensor with decreased sensitivity to shaft position variability

An angular position sensor, comprising:

• a magnet attached to a first shaft for rotation about a first axis;
• a first pole piece having first and second pole piece segments;
• a second pole piece having third and fourth pole piece segments, said first and third pole piece segments being spaced apart from each other by a fires predetermined distance, said first and third pole piece segments being disposed in magnetic field communication with said magnet, said magnet being disposed between said first and third pole piece segments, said first and second pole pieces being disposed in a common plane which is perpendicular to said first axis;
• and
• a magnetically sensitive device, said second and fourth pole piece segments being spaced apart form each other by a second predetermined distance, said second and fourth pole piece segments being disposed in magnetic field communication with said magnetically sensitive device, said first and second pole pieces being in magnetic field communication with said magnet and said magnetically sensitive device to form a magnetic circuit with air gaps between said first and third pole piece segments and said magnet and between said second and fourth pole piece segments and said magnetically sensitive device, said device being sensitive to the magnitude and direction of a magnetic field imposed on it for providing an output signal indicative of the angular position of said first shaft, said first and second pole pieces being generally equal in length between said magnet and said magnetically sensitive device.

An angular position sensor, comprising:

• means for rotating a magnetic field about a first axis in coordinated movement with a rotatable member;
• means for providing an electrical signal representative of the strength of said magnetic field at a preselected location spaced apart from said rotating means and indicative of the angular position of said rotatable member;
• first means for confining a first portion of said magnetic field along a first magnetic path;
• and
• second means for confining a second portion of said magnetic field along a second magnetic path, said rotating means being disposed between said first and second confining means, said rotating means and said first and second confining means being arranged to define a combined magnetic path extending through said providing means, said first and second confining means being disposed in a common plane which is perpendicular to said first axis, said first and second defined magnetic paths being generally equal in length.