Patent ID: 7658120
Filing Date: 2010-02-09
Classification: G01L,G01R

Abstract:
1. A magnetostrictive torque sensor comprising: a magnetostrictive film for which magnetic properties change in response to a magnitude of a torque acted to a shaft; a detection coil which detects variation of the magnetic properties of the magnetostrictive film; a current direction switching device which can invert a direction of a current which flows to the detection coil with respect to each predetermined time; and an inversion device which synchronizes with an inversion timing of the current by the current direction switching device and inverts a detection signal of the detection coil, wherein: when the current flows in a direction from one side to another side of the detection coil by the current direction switching device, the torque acted to the shaft is detected based on an input signal of the inversion device; and when the current flows in an inverse direction from another side to one side of the detection coil by the current direction switching device, the torque acted to the shaft is detected based on an output signal of the inversion device.