Abstract: A viscous clutch includes a shaft, a rotor disk, a housing having a base, a working chamber, a reservoir fluidically connected to the working chamber, a valve, an electromagnetic coil, and a flux guide that passes through the housing. The rotor disk includes a conductive portion made of a magnetic flux conductive material that forms a hub of the rotor disk that contacts the shaft and another portion. The base includes a hub with an axially-extending ring, and an armature of the valve is located radially outward of the axially-extending ring. The electromagnetic coil is located at an opposite side of the rotor disk from the reservoir. A magnetic flux circuit extends from the electromagnetic coil to the flux guide, then to the armature of the valve, then to the conductive portion of the rotor disk, then to the shaft, and then back to the electromagnetic coil.

Abstract: A viscous clutch includes an input member, an output member, a working chamber defined between the input member and the output member, a reservoir to hold a supply of a shear fluid, a valve that controls a flow of the shear fluid between the reservoir and the working chamber along a fluid circuit that fluidically connects the reservoir and the working chamber, a bearing, and an electromagnetic coil supported by the bearing. The electromagnetic coil includes a coil housing and a winding that forms multiple turns within an interior volume of the coil housing, wherein the coil housing has a stepped configuration to at least partially accommodate the bearing within a first step. Selective energization of the electromagnetic coil actuates the valve.

Abstract: A viscous clutch (20; 20?) includes a rotor (26), a housing (24) that at least partially surrounds the rotor, a center shaft (22) rotationally fixed to the housing, a mounting disk (30) rotationally fixed to the rotor, a working chamber (38) defined between the rotor and the housing, a reservoir (36) for holding a supply of shear fluid, an electromagnet (34), a valve assembly (32) to selectively control flow of the shear fluid between the reservoir and the working chamber, and a flux guide (54) operatively positioned between the electromagnet and the armature. At least a portion of the mounting disk extends outside the housing. The valve assembly including an armature (32-3) that is selectively movable in response to magnetic flux generated by the electromagnet, and the magnetic flux is transmitted between the armature and the electromagnet along a flux circuit. The flux guide extends through the mounting disk.

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 (20) includes an input member (26), an output member (24), a working chamber (30) defined between the input member and the output member, a reservoir (28) to hold a supply of a shear fluid, a valve (32) that controls a flow of the shear fluid between the reservoir and the working chamber along a fluid circuit that fluidically connects the reservoir and the working chamber, a bearing (48), and an electromagnetic coil (34) supported by the bearing. The electromagnetic coil includes a coil housing (34-1) and a winding (34-2) that forms multiple turns within an interior volume (34-3) of the coil housing, wherein the coil housing has a stepped configuration to at least partially accommodate the bearing within a first step (34-4). Selective energization of the electromagnetic coil actuates the valve.

Abstract: A viscous clutch includes a shaft, a rotor disk, a housing having a base, a working chamber, a reservoir fluidically connected to the working chamber, a valve, an electromagnetic coil, and a flux guide that passes through the housing. The rotor disk includes a conductive portion made of a magnetic flux conductive material that forms a hub of the rotor disk that contacts the shaft and another portion. The base includes a hub with an axially-extending ring, and an armature of the valve is located radially outward of the axially-extending ring. The electromagnetic coil is located at an opposite side of the rotor disk from the reservoir. A magnetic flux circuit extends from the electromagnetic coil to the flux guide, then to the armature of the valve, then to the conductive portion of the rotor disk, then to the shaft, and then back to the electromagnetic coil.

Abstract: A viscous clutch (20; 20?) includes a rotor (26), a housing (24) that at least partially surrounds the rotor, a center shaft (22) rotationally fixed to the housing, a mounting disk (30) rotationally fixed to the rotor, a working chamber (38) defined between the rotor and the housing, a reservoir (36) for holding a supply of shear fluid, an electromagnet (34), a valve assembly (32) to selectively control flow of the shear fluid between the reservoir and the working chamber, and a flux guide (54) operatively positioned between the electromagnet and the armature. At least a portion of the mounting disk extends outside the housing. The valve assembly including an armature (32-3) that is selectively movable in response to magnetic flux generated by the electromagnet, and the magnetic flux is transmitted between the armature and the electromagnet along a flux circuit. The flux guide extends through the mounting disk.

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 rotor, a housing member, a working chamber located between the housing member and the rotor, a reservoir to hold viscous fluid that is configured to rotate with the rotor, a return bore in fluid communication between the working chamber and the reservoir, a first passage from the reservoir to the working chamber, a second passage from the reservoir to the working chamber, and a valve. The second passage is spaced from the first passage, and can extend substantially radially through the rotor. The valve is configured to selectively regulate flow of the viscous fluid through the first passage, and the second passage is unobstructed such that the viscous fluid can pass from the reservoir to the working chamber regardless of the operational state of the valve. Viscous fluid present in the working chamber rotationally couples the rotor and the housing member.

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 viscous clutch includes a rotor, a housing member, a working chamber located between the housing member and the rotor, a reservoir to hold viscous fluid that is configured to rotate with the rotor, a return bore in fluid communication between the working chamber and the reservoir, a first passage from the reservoir to the working chamber, a second passage from the reservoir to the working chamber, and a valve. The second passage is spaced from the first passage, and can extend substantially radially through the rotor. The valve is configured to selectively regulate flow of the viscous fluid through the first passage, and the second passage is unobstructed such that the viscous fluid can pass from the reservoir to the working chamber regardless of the operational state of the valve. Viscous fluid present in the working chamber rotationally couples the rotor and the housing member.

Abstract: A valve assembly for a viscous clutch includes an orifice plate defining a bore to allow the passage of a fluid through the orifice plate, a reed valve secured relative to the orifice plate, an armature comprising a magnetic flux-conducting material, an anchor spring secured to the armature, and a stiffening plate. The reed valve includes a tongue configured to selectively cover the bore of the orifice plate, and a first pivot location along the tongue. A second pivot location is defined along the anchor spring at an edge of the stiffening plate. The first and second pivot locations are spaced from each other. The armature is configured to selectively apply a force to the reed valve to pivot at least a portion of the tongue about the first pivot location.

Abstract: A valve assembly for a viscous clutch includes an orifice plate defining a bore to allow the passage of a fluid through the orifice plate, a reed valve secured relative to the orifice plate, an armature comprising a magnetic flux-conducting material, an anchor spring secured to the armature, and a stiffening plate. The reed valve includes a tongue configured to selectively cover the bore of the orifice plate, and a first pivot location along the tongue. A second pivot location is defined along the anchor spring at an edge of the stiffening plate. The first and second pivot locations are spaced from each other. The armature is configured to selectively apply a force to the reed valve to pivot at least a portion of the tongue about the first pivot location.