Patent ID: 8424393

Claim:
A magnetic torque sensing device comprising: a generally disk-shaped member having opposite generally circular spaced apart surfaces, and forming a central axis of rotation; first and second ferromagnetic and magnetorestrictive magnetically conditioned regions disposed on or in at least a portion of the disk-shaped member forming a magnetoelastically active region for producing a magnetic field that varies with a torque applied to the disk-shaped member, wherein the magnetically active region possesses sufficient magnetic anisotropy to return the magnetization in the magnetoelastically active region to an initial state when the torque applied to the disk-shaped member is reduced to zero; and at least one pair of magnetic field sensors, each having a sensitive direction and disposed adjacent to one another and proximate to the magnetoelastically active region, wherein the sensitive direction of the first sensor is opposite the sensitive direction of the second sensor, and perpendicular to the direction of polarization of the first and second magnetically conditioned regions, wherein the magnetic field sensors provide an output signal that is representative of the torque applied to the disk-shaped member, and wherein variation in the output signal is substantially linear with respect to variation in the torque applied to the disk-shaped member.