Patent ID: 8635917

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; a radially-extending magnetorestrictive magnetically conditioned region 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 a plurality of magnetic field sensors disposed proximate to the magnetically conditioned region, each of the magnetic field sensors having a sensitive direction that is perpendicular to a direction of polarization of the magnetically conditioned region, wherein the magnetic field sensors are symmetrically arranged such that, for a first magnetic field sensor having its sensitive direction oriented in a first direction, a second corresponding magnetic field sensor has its sensitive direction oriented in a second direction, opposite the first direction, to cancel the effect of common mode noise sensed by the first and second magnetic field sensors, and 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.