Patent ID: 8836267
Filing Date: 2014-09-16
Classification: B62D,G01L

Abstract:
1. A torque detection device, comprising: an elastic member that couples a first shaft to a second shaft such that the first shaft and the second shaft are rotatable relative to each other, and that is twisted as a torsional torque is input into a portion between the first shaft and the second shaft; an annular magnet that is coaxially fixed to the first shaft, and in which N-poles and S-poles are alternately formed in a circumferential direction; a pair of annular magnetic yokes that are coaxially fixed to the second shaft, that surround the magnet in a noncontact state, and that are arranged so as to face each other in an axial direction; a pair of annular magnetic flux concentration rings that respectively surround the pair of magnetic yokes and that guide and concentrate the magnetic fluxes generated in the pair of magnetic yokes, and a magnetic sensor that is arranged between the pair of magnetic flux concentration rings and that detects the density of magnetic fluxes concentrated by the magnetic flux concentration rings, wherein each of the pair of magnetic yokes includes an annular yoke ring and a plurality of lugs that are extended in the axial direction from the corresponding yoke ring and that are arranged at equal intervals in the circumferential direction, each yoke ring includes an extending portion that extends radially outward from base portions of the lugs and a bent portion that is bent in the axial direction from a radially outer end portion of the extending portion, and distal end portions of the lugs of one of the magnetic yokes distal end portions of the lugs of the other magnetic yoke are arranged alternately in the circumferential direction, and an outer size of the pair of magnetic yokes in the axial direction is larger than or equal to a length of the magnet in the axial direction.