Torque sensor, robot, and torque calculation method

A robot comprising a torque sensor at a tip of an arm, wherein

• the torque sensor includes
• a strain body, and
• a sensor configured to detect a deformation of the strain body,
• the strain body includes
• an outer peripheral body having a ring shape,
• an inner peripheral body of which at least a part is disposed inside the outer peripheral body in a radial direction, and
• a protrusion provided in the outer peripheral body, and protruding from an end of the inner peripheral body in an axial direction toward one side of the axial direction, and the torque sensor further includes
• a seal disposed between the protrusion and a functional operator to which the outer peripheral body or the inner peripheral body is fixed, the functional operator including a slide bearing that is provided with an outer ring, and an inner ring rotatable with respect to the outer ring along with a sliding body disposed between the inner ring and the outer ring.

A torque calculation method comprising:

• providing a torque sensor including
• a strain body, and
• a plurality of optical sensors arranged at a plurality of positions of the strain body in a circumferential direction, and configured to detect a deformation of the strain body,
• wherein the strain body includes
• an outer peripheral body having a ring shape, and
• an inner peripheral body of which at least a part is disposed inside the outer peripheral body in a radial direction, and
• wherein each of the plurality of optical sensors includes
• a scale fixed to one of the outer peripheral body and the inner peripheral body, and disposed between the outer peripheral body and the inner peripheral body, and
• a detector fixed to a remaining one of the outer peripheral body and the inner peripheral body, and disposed to face the scale between the outer peripheral body and the inner peripheral body, and
• wherein a substrate of the torque sensor is disposed in a space formed between the outer peripheral body and the inner peripheral body, and is provided with the detector,
• acquiring outputs of the plurality of optical sensors;
• and
• adding the outputs of the plurality of optical sensors, thereby calculating a torque based on a result of the addition.