Patent ID: 8667854

Claim:
A torque sensor for detecting torque about a predetermined rotation axis, comprising: an annular deformation body made of a material that produces elastic deformation due to exertion of torque to be detected, having a through-opening portion through which the rotation axis is inserted; a left side support body disposed at a position adjacent to a left side of the annular deformation body, when viewed in such a reference observation direction that the rotation axis creates a horizontal line extending left and right; a right side support body disposed at a position adjacent to a right side of the annular deformation body, when viewed in the reference observation direction; a left side connection member for connecting a left side connection point on a left-hand side surface of the annular deformation body to the left side support body; a right side connection member for connecting a right side connection point on a right-hand side surface of the annular deformation body to the right side support body; a displacement electrode fixed to an inner peripheral surface or an outer peripheral surface of the annular deformation body, for producing displacement caused by elastic deformation of the annular deformation body; a fixed electrode disposed at a position opposed to the displacement electrode, fixed to the left side support body or the right side support body; and a detector circuit for outputting an electrical signal indicating torque about the rotation axis exerted on one of the right side support body and the left side support body with the other loaded, based on an amount of fluctuation in capacitance value of a capacitive element composed of the displacement electrode and the fixed electrode; wherein an orthogonal projection image of the left side connection point and an orthogonal projection image of the right side connection point with respect to a plane of projection orthogonal to the rotation axis are formed at different positions; the displacement electrode is constructed by a conductive layer formed on an inner peripheral surface of the annular deformation body; and the fixed electrode is constructed by a conductive plate disposed at a position opposed to the conductive layer and projecting in a direction along the rotation axis from the left side support body or the right side support body.