Patent ID: 7870939

Claim:
A magnetorheological clutch comprising: a stationary part, a rotatable primary part with primary discs, and a secondary part having secondary discs which surrounds the primary part and is rotatable about a common axis of rotation; a space containing a magnetorheological fluid formed between the primary part and the secondary part in which the primary discs and the secondary discs alternate in the axial direction; and a regulatable magnetic field which acts on the magnetorheological fluid, wherein a) a plurality of magnetic coils are axially arranged in front of or behind the space containing the magnetorheological fluid and are operable to build up the magnetic field in a first yoke; b) the first yoke has an end face parallel to the discs which is adjoined by the space containing the magnetorheological fluid, wherein magnetic field lines emerge substantially at right angles from said end face and enter into it respectively, and c) a second yoke having an end face parallel to the discs is provided at the side of the space remote from the first yoke, wherein the discs are plates which consist of a material having a magnetic permeability in the range from 0.6 to 1.2 Tesla, and wherein the plurality of magnetic coils are uniformly distributed over the periphery and each is associated with one of the first and second yokes, said magnetic coils each having a winding axis and magnetic core radially aligned with the respective axis of rotation.