Patent ID: 8650969

Claim:
An electrically-assisted power steering apparatus comprising: a magnetostrictive torque sensor comprising: a rotation shaft rotationally supported, the rotation shaft serving as a steering axle; a magnetostrictive member disposed on a surface of the rotation shaft and being deformable in accordance with a magnitude of rotation torque applied to the rotation shaft to change magnetic permeability; and a plurality of detectors disposed on a periphery of the rotation shaft each of the detectors being configured to detect a change in magnetic permeability of the magnetostrictive member in a form of an electrical change, the detectors being configured to detect different amounts of electrical change from one another if amounts of change in deformation are same throughout the magnetostrictive member; a rack and pinion gear mechanism to transfer rotation of the steering axle; and a bearing disposed between the detector and the rack and pinion gear mechanism, the bearing rotatably supporting the steering axle, wherein the detectors are disposed to be shifted from each other in an axis direction of the rotation shaft, wherein the at least two detectors includes a first detector and a second detector, the second detector being disposed nearer to the bearing than the first detector, and wherein if amounts of change in deformation are the same throughout the magnetostrictive member, the second detector detects an electrical change that is smaller than an electrical change detected by the first detector.