Torque transmission device, braking apparatus, and power transmission apparatus

A braking apparatus comprising a torque transmission apparatus that generates torque corresponding to a relative rotational speed between two shafts by using a shearing force of a viscous fluid so as to reduce a speed difference, the torque transmission apparatus comprising:

• a case member that forms an operation chamber that contains the viscous fluid;
• a shaft that is inserted through the case member so as to be capable of rotating relative to the case member;
• a plurality of first plates that are connected to the case member;
• and
• a plurality of second plates that are connected to the shaft and provided spaced apart from the first plates in a thickness direction,
• wherein the second plates are movable plates capable of swinging within a plane perpendicular to an axis of the shaft, and
• the first plates are attached to an inner circumferential surface of the case member, and the movable plates are swingably supported about a position at a distance from the rotational axis of the shaft,
• the movable plates are held at a first position, at which the interlocking area between the first plates and the movable plates is small, by the elastic member when a relative rotational speed between the case member and the shaft is small, and
• when the relative rotational speed between the case member and the shaft exceeds a predetermined value, the movable plates are pivotally moved toward the first plates by the shearing force of the viscous fluid generated between plates by relative rotation, and held at a second position at which the interlocking area between the movable plates and the first plates is large, so as to switch an interlocking area between the plates and control a value of torque generated between the case member and the shaft.