magnetostriktiver drehmomentsensor and electrical power steering with such a sensor

摘要

PROBLEM TO BE SOLVED: To provide a magnetostrictive torque sensor capable of detecting a failure of a magnetostrictive film easily and accurately with a simple constitution, and shortening as much as possible a magnetostrictive film formation space on a rotating shaft, and an electric power steering device.;SOLUTION: The magnetostrictive torque sensor is constituted of a rotating shaft 11; the first magnetostrictive film 14A, the second magnetostrictive film 14B and the third magnetostrictive film 14C formed over the whole periphery in the circumferential direction on the surface of the rotating shaft; the first detection coil 13A, the second detection coil 13B and the third detection coil 13C for detecting each impedance change of the first magnetostrictive film, the second magnetostrictive film and the third magnetostrictive film; a torque calculation part 17 for inputting a signal with respect to the impedance change output from the first to third detection coils, and calculating a torque applied to the rotating shaft based on an output signal from the first detection coil and an output signal from the second detection coil; and a failure detection part 18 for detecting a failure of the first magnetostrictive film or the second magnetostrictive film by comparing each output signal from the first to third detection coils.;COPYRIGHT: (C)2007,JPO&INPIT