TORQUE SENSOR

PROBLEM TO BE SOLVED: To provide a torque sensor which is small, has high rigidity, and whose structure is simple.SOLUTION: An annular deformable body 30 is arranged between a rotor 10 and a rotor 20. Convex parts 11, 12 projected from the rotor 10 are joined to two upper and lower parts of the left side face of the annular deformable body 30, and convex parts 21, 22 (not illustrated) projected from the rotor 20 are joined to two front/rear parts of the right side face. Outer peripheries of the rotors 10, 20 are freely rotatably supported on the inner surface of a cylindrical housing 40 by bearings 15, 25. Rotation drive force added from a drive shaft 13 to the rotor 10 is transmitted from the rotor 20 to a driven shaft 23. The annular deformable body 30 rotates while being elliptically deformed by a load to be added to the driven shaft 23, distance between the outer peripheral surface 30E of the annular deformable body 30 and a fixed electrode E fluctuates. Thus, a capacitance value of a capacitive element C to be constituted of both fluctuates. A measuring circuit 51 calculates a distance measurement value d by the capacitance value, and a detection circuit 60 detects a rotation load as torque T by its amplitude.