Patent ID: 7191668

Claim:
A torque measuring device for a rotating body, the device comprising: a rotary section including a first flange provided at a driving side, a second flange provided at a driven side, and a hollow cylinder provided between the first and second flanges; a plurality of light emitting elements provided at an outer circumference of the rotary section, and functioning to emit light based on output from each of torque detectors provided at an inner surface of the hollow cylinder thereby sending an optical signal; a light conductive member comprising a rod member shaped substantially into a rectangular pole, the conductive member functioning to receive the optical signal at a light receiving surface thereof facing toward the rotary section, and to guide the optical signal along its longitudinal directions, the light conductive member having an optical path converting means formed at one of the light receiving surface and a surface opposite to the light receiving surface and having a plurality of grooves formed in a longitudinal direction of the light conductive member each defining inclined planes with a flat portion defined between adjacent grooves, the grooves having ridges extending in a direction orthogonal to a longitudinal direction of the light conducting member; and, a torque calculator to calculate torque of the rotary section based on the optical signal guided by the light conductive member.