The system includes: a driver; a rotating load configured to be driven into rotation by the driver; a controller, for controllably changing a rotation speed of the load; and a variable speed transmission, arranged between the driver and the load. The variable speed transmission includes a speed summing gear arrangement with a first input shaft, a second input shaft and an output shaft. The output shaft is drivingly coupled to the rotating load. The first input shaft is drivingly coupled to the driver. A continuous variable transmission device is mechanically coupled to the driver and to the second input shaft of the speed summing gear arrangement. The continuous variable transmission device is functionally coupled to the controller.

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.

An internal combustion engine including a cooling liquid circuit, which is connected to a cylinder head and an engine block of the internal combustion engine and which includes a cooling liquid pump. The cooling liquid pump includes a drive shaft and is capable of conveying cooling liquid in the cooling liquid circuit. Further, the internal combustion engine includes a Visco clutch. The Visco clutch is arranged for the drive by the internal combustion engine. The Visco clutch includes a clutch fluid for torque transmission. At the output side, the Visco clutch is connected to the drive shaft of the cooling liquid pump. The drive shaft of the cooling liquid pump include at least one heat pipe. The heat pipe is in heat exchange with the clutch fluid as a heat source and the cooling liquid as a heat sink.

Outer plates have a doughnut-like disk shape and are attached to the inner circumferential surface of a case member. On the other hand, inner plates have a substantially arc shape and are swingably supported about a position at a distance from the center of rotation of a shaft. The inner plates are held at a first position, at which the interlocking area between the outer plates and the inner plates is small, by a tension coil spring when the relative rotational speed between the case member and the shaft is small, and, when the relative rotational speed between the case member and the shaft exceeds a predetermined value are pivotally moved toward the outer plates by the shearing force of a viscous fluid and held at a second position at which the interlocking area between the movable plates and the first plates is large.

Outer plates have a doughnut-like disk shape and are attached to the inner circumferential surface of a case member. On the other hand, inner plates have a substantially arc shape and are swingably supported about a position at a distance from the center of rotation of a shaft. The inner plates are held at a first position, at which the interlocking area between the outer plates and the inner plates is small, by a tension coil spring when the relative rotational speed between the case member and the shaft is small, and, when the relative rotational speed between the case member and the shaft exceeds a predetermined value are pivotally moved toward the outer plates by the shearing force of a viscous fluid and held at a second position at which the interlocking area between the movable plates and the first plates is large.

A clutched compressor section of a gas turbine engine coupled to a rotor shaft. The clutched compressor section includes at least one decoupleable rotor stage, the decoupleable rotor stage switchable between a coupled condition and a decoupled condition with a clutch mechanism, the coupled condition coupling the decoupleable rotor stage with the rotor shaft, the decoupled condition decoupling the decoupleable rotor stage from the rotor shaft.

A clutched compressor section of a gas turbine engine coupled to a rotor shaft. The clutched compressor section includes at least one decoupleable rotor stage, the decoupleable rotor stage switchable between a coupled condition and a decoupled condition with a clutch mechanism, the coupled condition coupling the decoupleable rotor stage with the rotor shaft, the decoupled condition decoupling the decoupleable rotor stage from the rotor shaft.

A viscous clutch includes an input member, an output member, a working chamber, a reservoir to hold a supply of a shear fluid, an outlet, a return bore, an accumulator, and a first wall having an arcuate segment. The reservoir is connected to the working chamber by a fluid circuit, along which the outlet passes the shear fluid from the reservoir to the working chamber and the return bore returns the shear fluid pumped out of the working chamber to the accumulator. The accumulator is arranged in series with the reservoir in the fluid circuit. The first wall is positioned within the reservoir to separate a first portion from a second portion.

A viscous clutch head may be replaced by selecting a viscous clutch head and a mount adapter. The viscous clutch head and the mount adapter may be selected from a group of universal modular fan drives and from a group of mount adapters. The mount adapter of a threaded type or a flange and bolt type may be selected. Depending on the viscous clutch head to be replaced, a fan adapter and/or a pilot adapter may also be selected from a group of fan adapters and from a group of pilot adapters. Accordingly, a range of models of viscous fan clutch systems may be replaced by using a limited number of parts. These parts may be stored on a tool cart. As different models of viscous fan clutch systems may be replaced using a limited number of parts, the in-stock inventory of replacement parts may be reduced.

A viscous clutch head may be replaced by selecting a viscous clutch head and a mount adapter. The viscous clutch head and the mount adapter may be selected from a group of universal modular fan drives and from a group of mount adapters. The mount adapter of a threaded type or a flange and bolt type may be selected. Depending on the viscous clutch head to be replaced, a fan adapter and/or a pilot adapter may also be selected from a group of fan adapters and from a group of pilot adapters. Accordingly, a range of models of viscous fan clutch systems may be replaced by using a limited number of parts. These parts may be stored on a tool cart. As different models of viscous fan clutch systems may be replaced using a limited number of parts, the in-stock inventory of replacement parts may be reduced.