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.

A viscous clutch (20) includes a housing assembly (28), a rotor assembly (26), a reservoir (38) to hold a supply of a shear fluid, a working chamber (40) operatively positioned between the housing assembly and the rotor assembly, and a fluid return bore (26-1B) that optionally extends radially through at least an outer diameter portion of the rotor assembly to the working chamber. Selective introduction of the shear fluid to the working chamber facilitates selective torque transmission between the housing assembly and the rotor assembly. The fluid return bore can form at least a portion of a fluid return path (50) from the working chamber to the reservoir.

A viscous clutch (20) includes a housing assembly (28), a rotor assembly (26), a reservoir (38) to hold a supply of a shear fluid, a working chamber (40) operatively positioned between the housing assembly and the rotor assembly, and a fluid return bore (26-1B) that optionally extends radially through at least an outer diameter portion of the rotor assembly to the working chamber. Selective introduction of the shear fluid to the working chamber facilitates selective torque transmission between the housing assembly and the rotor assembly. The fluid return bore can form at least a portion of a fluid return path (50) from the working chamber to the reservoir.

A viscous clutch (20) includes a housing assembly (28), a rotor assembly (26), a reservoir (38) to hold a supply of a shear fluid, a working chamber (40) operatively positioned between the housing assembly and the rotor assembly, and a fluid return bore (26-1B) that optionally extends radially through at least an outer diameter portion of the rotor assembly to the working chamber. Selective introduction of the shear fluid to the working chamber facilitates selective torque transmission between the housing assembly and the rotor assembly. The fluid return bore can form at least a portion of a fluid return path (50) from the working chamber to the reservoir.

A viscous clutch (20) includes a housing assembly (28), a rotor assembly (26), a reservoir (38) to hold a supply of a shear fluid, a working chamber (40) operatively positioned between the housing assembly and the rotor assembly, and a fluid return bore (26-1B) that optionally extends radially through at least an outer diameter portion of the rotor assembly to the working chamber. Selective introduction of the shear fluid to the working chamber facilitates selective torque transmission between the housing assembly and the rotor assembly. The fluid return bore can form at least a portion of a fluid return path (50) from the working chamber to the reservoir.

A torque converter includes a torsional damper assembly. The torsional damper assembly includes a damper. The damper has an electromagnetic coil and a magnetorheological fluid. The electromagnetic coil is positioned such that a magnetic field from the electromagnetic coil adjusts a viscosity of the magnetorheological fluid when a current flows through the electromagnetic coil.

A power transmission device according to an aspect of the present disclosure includes a first drive unit having a first drive source, a first transmission connected to the first drive source and the driving force to be transmitted, a second drive source, and a second transmission connected to the second drive source and the driving force to be transmitted, and includes a second drive unit arranged in parallel with the first drive unit, and a frictional differential limiting element disposed between the first transmission and the second transmission and limiting a differential between the rotational drive of the first transmission and the rotational drive of the second transmission.

A power transmission device according to an aspect of the present disclosure includes a first drive unit having a first drive source, a first transmission connected to the first drive source and the driving force to be transmitted, a second drive source, and a second transmission connected to the second drive source and the driving force to be transmitted, and includes a second drive unit arranged in parallel with the first drive unit, and a frictional differential limiting element disposed between the first transmission and the second transmission and limiting a differential between the rotational drive of the first transmission and the rotational drive of the second transmission.

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.