Patent ID: 6341535
Filing Date: 2002-01-29
Classification: G01L

Abstract:
A torque detection assembly comprising:an elastic member disposed between a first shaft and a second shaft, said elastic member allowing torsional displacement to occur between said first shaft and said second shaft in response to torque acting between said first shaft and said second shaft; magnetic elements each being fastened to said first shaft and said second shaft, said magnetic elements being displaced by said torsional displacement between said first shaft and said second shaft; a coil wound so as to surround said magnetic elements, magnetic flux being generated by passage of an alternating drive current through said coil; and a yoke disposed so as to surround said coil, said yoke guiding said magnetic flux to said magnetic elements, the thickness of said yoke and said magnetic elements being not more than twice a skin depth &dgr; calculated by a formula: &dgr;={square root over ( )}(2&rgr;/(2&pgr;.F.&mgr;s.&mgr;0))â€ƒâ€ƒ(1) where&rgr; is the specific resistance of said magnetic elements, F is the frequency of the magnetic field, &mgr;s is the specific permeability of said magnetic elements, and &mgr;0 is the permeability of a vacuum.