Abstract: A viscous friction clutch includes a rotor, a housing that is rotatable relative to the rotor, a working chamber located between the rotor and the housing such that a volume of shear fluid can be selectively introduced to the working chamber to contact both the rotor and the housing, an electromagnetic coil, a valve assembly that controls the volume of the shear fluid present in the working chamber, and a flux path that magnetically links the electromagnetic coil and the valve assembly. The flux path passes through a flux guide part made of a ferromagnetic material that extends through the rotor in an interior of the viscous friction clutch and across a flux gap that traverses both an air gap and a non-ferromagnetic portion of the housing.

Abstract: A viscous friction clutch includes a rotor, a housing that is rotatable relative to the rotor, a working chamber located between the rotor and the housing such that a volume of shear fluid can be selectively introduced to the working chamber to contact both the rotor and the housing, an electromagnetic coil, a valve assembly that controls the volume of the shear fluid present in the working chamber, and a flux path that magnetically links the electromagnetic coil and the valve assembly. The flux path passes through a flux guide part made of a ferromagnetic material that extends through the rotor in an interior of the viscous friction clutch and across a flux gap that traverses both an air gap and a non-ferromagnetic portion of the housing.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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, and a reservoir 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.

Abstract: 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.

Abstract: 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, and a reservoir 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.

Abstract: A fluid friction coupling for driving a fan of an internal combustion engine includes a solenoid configured such that it surrounds a drive shaft and is operatively arranged for moving a control part. The control part moves a valve body which controls the flow of a viscous fluid into a working chamber. The fluid friction coupling is of particularly compact configuration and magnetic losses are kept particularly low.