Patent ID: 6443020
Filing Date: 2002-09-03
Classification: B62D

Abstract:
A sensor for measuring differential angular displacement between an upper shaft segment and a lower shaft segment, comprising:an upper ring-shaped target wheel coupled to the upper shaft segment, the upper target wheel forming a plurality of enclosed slots; a lower ring-shaped target wheel coupled to the lower shaft segment and coaxially aligned with the upper target wheel, the lower target wheel forming a plurality of enclosed slots; at least one excitation coil energizable to create an alternating current magnetic field that generates eddy current in the target wheels, the excitation coil being coaxial with the upper and lower target wheels and placed below the upper and lower target wheels; and at least one ring-shaped receiver/reference coil assembly placed above the upper and lower target wheels, the receiver/reference coil assembly including at least one ring-shaped receiver coil and at least one ring shaped reference coil within the ring-shaped receiver coil, the ring-shaped reference coil being concentric to the ring-shaped receiver coil.