Abstract: An apparatus measures relative displacement between a first end and a second end of a shaft. The first and second ends being centered on a shaft axis. The apparatus includes first and second ferromagnetic plates. The first ferromagnetic plate has a first side and a second side and is connected to the first end. The first ferromagnetic plate is centered on the shaft axis and has a plurality of ferromagnetic teeth extending from the first side and in a first direction parallel to the shaft. The second ferromagnetic plate has a first side and a second side and is connected to the second end. The second ferromagnetic plate is centered on the shaft axis. The first and second ferromagnetic plates form a gap. The apparatus further includes a plurality of magnets having a magnetic field and a sensing device. The magnets are coupled to the first side of the second ferromagnetic plate. The sensing device is disposed within the gap for sensing a magnetic flux of the magnetic field.

Abstract: A flux-gate magnetometer torque sensor is provided having a rotatable shaft to which a torque force is to be applied, a sleeve of conductive foil affixed to the surface of the shaft over the magnetically active regions, a plurality of saturable magnetic wires or strips mounted to the rotatable shaft and parallel to an axis of rotation, sensor circuitry containing an oscillator for generating a signal, a divider coupled to the oscillator for dividing the frequency of the signal by two, a first and second coil each surrounding a different section of the rotatable shaft and having an input coupled to the divider output, a multiplier having inputs coupled to outputs of the first coil, the second coil, and the oscillator, and an integrator having an input coupled to the multiplier output and an output coupled to both outputs of the first and second coils, wherein the output voltage of the integrator corresponds to the torque being applied to the rotatable shaft.

Abstract: An apparatus for contact-less measuring a difference angle between two parts rotating about a common axis comprises a stator having magnetic pole pairs, and a ferromagnetic rotor having pole ends for magnetically scanning the pole pairs of the stator. There are a first air gap between the pole pairs of the stator and the pole ends of the rotor; and an accessible and rotationally symmetric second air gap between the stator and the rotor. The magnetic flux across the second air gap is changed according to the difference angle between the rotor and the stator. This is determined by a magnetically sensitive element which is arranged at a fixed position within the second air gap.