A viscous clutch includes a shaft, a rotor attached to the shaft, a housing located adjacent to the rotor, a working chamber defined between the rotor and the housing, a reservoir used to store a shear fluid, a valve assembly, an electromagnetic coil, and a flux insert in the housing. Selective introduction of the shear fluid to the working chamber facilitates selective torque transmission between the rotor and the housing. The valve assembly regulates flow of the shear fluid between the reservoir and the working chamber, and includes an armature. Selective energization of the electromagnetic coil governs actuation of the valve assembly. A flux circuit is provided that extends from the electromagnetic coil to the armature and back to the electromagnetic coil. The flux circuit passes through the flux insert and through the shaft, and the flux circuit crosses a radial air gap between the flux insert and the armature.

A viscous clutch (30; 130; 230) includes a shaft (32; 132; 232), a rotor (34; 134; 234) attached to the shaft, a housing (36; 136; 236) located adjacent to the rotor, a working chamber (40; 140; 240) defined between the rotor and the housing, and a reservoir (38; 138; 238) used to store a shear fluid. Selective introduction of the shear fluid to the working chamber facilitates selective torque transmission between the rotor and the housing. The reservoir is attached to the shaft separately from the rotor.

Viscous fan drive systems with wiper members positioned on the OD of the clutch disks, and which rotate at high speed. The fluid reservoir also rotates at input speed. The wiper member directs viscous fluid radially back to the fluid reservoir. The valves in the viscous fan drive systems can be activated by a bimetal mechanism.

A device that employs shear forces to transmit energy includes an outer housing assembly, a disk, and a reservoir with a working fluid. The disk is received in and rotatable relative to the outer housing assembly. A working cavity is formed between a rotor portion of the disk and the outer housing assembly into which the working fluid is received to create shear forces. A plurality of flow altering structures are disposed on the outer housing assembly and are configured to reduce a thickness of a boundary layer of the working fluid in the working cavity in areas that are local to the flow altering structures.

A fluid fan clutch according to the present invention comprises: a fan housing provided with a housing main body having a concave fluid operating chamber formed at a center part thereof, and a housing cover, which has a concave fluid storing chamber formed at the center part thereof and is laminated to cover an opening of the fluid operating chamber, and having a fluid collecting hole and a fluid outlet respectively formed on a bottom plate and a side wall of the fluid storing chamber; a rotor rotation shaft provided so as to penetrate the bottom plate of the housing main body; a rotor fixed and coupled to the rotor rotation shaft in the fluid operating chamber; a valve ring formed in a ring-shape to be adhered to an inner wall of the fluid storing chamber and having a penetration hole formed at a point corresponding with the fluid outlet; and a check valve provided inside the fluid storing chamber as a rotatable structure to seal one of the fluid collecting hole and the penetration hole according to the rotation angle and open the other.

The invention relates to an auxiliary drive device (1) comprising an electric motor (10, 11); and a mechanical clutch, wherein the electric motor (10, 11) and the mechanical clutch have the same axis of rotation (R), the mechanical clutch is designed as a fluid-friction clutch (20), and the electric motor (10, 11) and the fluid-friction clutch (20) are mechanically connected to one another.

A viscous clutch assembly includes a rotationally fixed center shaft, a rotor rotatably supported on the center shaft, a housing rotatably supported on the center shaft, a working chamber, a reservoir carried by the rotor, an electromagnetic coil located at or near a front end of the center shaft, a valve subassembly magnetically operable to control flow of a shear fluid between the reservoir and the working chamber, a flux guide extending axially across a cover of the housing, and a magnetic flux insulating material positioned adjacent to and radially inward from the flux guide. A flux circuit located forward of the rotor connects the electromagnetic coil and the valve subassembly and passes through the flux guide and the center shaft, with the magnetic flux insulating material at least partially surrounded by the flux circuit.

A viscous clutch assembly includes a rotationally fixed center shaft, a rotor rotatably supported on the center shaft, a housing rotatably supported on the center shaft, a working chamber, a reservoir carried by the rotor, an electromagnetic coil located at or near a front end of the center shaft, a valve subassembly magnetically operable to control flow of a shear fluid between the reservoir and the working chamber, a flux guide extending axially across a cover of the housing, and a magnetic flux insulating material positioned adjacent to and radially inward from the flux guide. A flux circuit located forward of the rotor connects the electromagnetic coil and the valve subassembly and passes through the flux guide and the center shaft, with the magnetic flux insulating material at least partially surrounded by the flux circuit.