Patent ID: 7621368

Claim:
An electric power steering apparatus, comprising: a motor for providing steering assist torque to a steering system; a steering torque sensor for detecting a steering torque in the steering system; and control means for controlling an operation of the motor on the basis of at least a steering torque signal output from the steering torque sensor, wherein the steering torque sensor is a magnetostrictive torque sensor including a magnetostrictive coat provided on a rotational shaft, the magnetostrictive coat having a magnetic anisotropy imparted thereto by subjecting the magnetostrictive coat to a heating process with a predetermined twisting torque kept applied to the rotational shaft and then removing the twisting torque from the rotational shaft, the magnetostrictive coat provided on the rotational shaft being then subjected to a reheating process at a temperature higher than a normal use temperature at which the magnetostrictive torque sensor is actually used for torque detection.