Patent ID: 8627794

Claim:
A fluid brake device comprising: a case defining a fluid chamber inside; magneto-rheological fluid, which has a viscosity variable according to a magnetic flux passing therethrough, contained in the fluid chamber; a viscosity control section to carry out variable control of the viscosity of the magneto-rheological fluid by modifying magnetic flux passing through the magneto-rheological fluid in the fluid chamber; a brake member which has a brake shaft penetrating the case and is rotatably supported on the case to come into contact with the magneto-rheological fluid so that the brake member receives a braking torque according to the viscosity of the magneto-rheological fluid; a sealing structure which seals between the case and the brake shaft; a thermo-sensitive chamber formed on a supporting member provided by one of the case and the brake member so as to be thermally conductive with the fluid chamber; a movable member which has an inner part accommodated in the thermo-sensitive chamber, and an exposed part exposed to the fluid chamber by being supported on the supporting member; and a variable-volume member disposed in the thermo-sensitive chamber, the variable-volume member being configured to change a volume itself in response to a temperature in the thermo-sensitive chamber, and applying force on the inner part to move the movable member so that a volume of the fluid chamber is increased as the temperature in the thermo-sensitive chamber is increased.