Action force detecting unit for rotary member

An action force detecting unit for a rotary member that is arranged between a predetermined rotary member and a predetermined stationary member supporting the rotary member in a rotatable manner to detect a force acting on the rotary member, comprising:

• a first rotor that is connected to the rotary member to be rotated integrally with the rotary member;
• a second rotor that is arranged coaxially with the first rotor to be opposed to the first rotor while being allowed to rotate relatively to the first rotor;
• a supporting member that is fixed to the stationary member while supporting the first rotor and the second rotor respectively in a rotatable manner;
• a first thrust bearing that is interposed between the first rotor and the supporting member to support the first rotor by receiving a thrust force acting on the first rotor in a direction along a rotational center axis;
• a second thrust bearing that is interposed between the second rotor and the supporting member to support the second rotor by receiving a thrust force acting on the second rotor in the direction along the rotational center axis;
• a load translating mechanism that is arranged between the first rotor and the second rotor to be rotated integrally with the first rotor and the second rotor, so as to transmit a torque between the first rotor and the second rotor while translating the torque partially into a thrust force transmitted between the first rotor and the second rotor;
• a detector including
• a flexure element that is partially fixed to the supporting member, and that is deformed by at least any one of the thrust force acting on the first thrust bearing and the thrust force acting on the second thrust bearing, and
• a sensor element that is attached to the flexure element to detect a physical amount relating to the thrust force deforming the flexure element;
• a calculator that calculates the force acting on the rotary member based on the physical amount detected by the detector;
• and
• a transmitter that is arranged on the supporting member, and that transmits an output signal to the calculator in accordance with the physical amount detected by the detector, or to an external element in accordance with the force calculated by the calculator.