Passive magnetorheological clutch

摘要

A passive magnetorheological clutch includes an input member that is constantly driven at engine speed, or some selected proportion thereof. An output member is journaled on the input member so as to be supported thereon in a nonrotating state and to be concentrically rotatable in concert therewith. A space presented between the input and output members contains a quantity of magnetorheological fluid. The space also contains an engagement mechanism including a permanent magnet and a ferromagnetic ring concentrically positioned with an operative gap therebetween, wherein the operative gap's dimension is variable to effect changes in the magnetic field passing between the magnet and the ring. When an actuator effects a reduction in the distance between the magnet and ring, the amount of magnetic field increases in density adjacent the ring. The resultant torque transfer from the input member to the output member is effected across the operative gap and through the magnetorheological fluid. As the operative gap is reduced, the torque transfer increases in a gradual and progressive manner.