Patent ID: 7287440

Claim:
A torque sensor comprising a housing, a first shaft and a second shaft accommodated in the housing and connected coaxially by a torsion bar, and a magnetism generation portion attached to the first shaft so as to surround the outer circumference of the first shaft and outputting a magnetic flux in the axis core direction of the first shaft, in which a plurality of magnetic yoke portions comprising a first magnetic yoke and a second magnetic yoke for guiding the magnetic flux outputted from the magnetism generation portion are attached to the second shaft; and a torque between the first shaft and the second shaft is detected magnetically by a magnetic sensor through detection of the magnetic flux in a magnetic gap between the first magnetic yoke and the second magnetic yoke, wherein the first magnetic yoke and the second magnetic yoke have their one end opposed to the magnetism generation portion, respectively, and the first magnetic yoke and the second magnetic yoke are bent in the L shape in the middle and extended in the direction crossing the axis core of the second shaft, respectively, and the other ends of the first magnetic yoke and the second magnetic yoke are provided separately from each other in the axis core direction on the outer circumference side of the second shaft; the other ends of the first magnetic yokes of each magnetic yoke portion are connected to each other by a first magnetic ring; the other ends of the second magnetic yokes of each magnetic yoke portion are connected to each other by a second magnetic ring; and the magnetic sensor is provided in the magnetic gap between the first magnetic ring and the second magnetic ring.