A control device for a clutch, which is provided between an operation machine and a drive shaft of an engine, controls an operation of a valve member for opening and closing an oil supply port through which an oil reservoir chamber and a torque transmission chamber communicate. The control device refers to a desired rotation speed of a rotating body of the operation machine and to an acquired rotation speed of the rotating body of the operation machine, calculates a proportional term manipulated variable based on a deviation between an angular acceleration of the rotating body and a desired angular acceleration, and controls the operation of the valve member on the basis of this calculated proportional term manipulated variable.

A viscous clutch includes an input member rotatable about an axis of rotation, an output member selectively rotatable about the axis of rotation, a working chamber bounded by the input member and the output member, a reservoir, a release bore that fluidically connects the reservoir to the working chamber, a leading wiper that extends into the working chamber, a leading pump bore positioned adjacent to the leading wiper that fluidically connects the working chamber to the reservoir, a trailing wiper that extends into the working chamber, and a trailing pump bore positioned adjacent to the trailing wiper and downstream of the leading pump bore that fluidically connects the working chamber to the reservoir. The trailing wiper has a width that is greater than a width of the leading wiper.

A controller includes: a control unit configured to calculate a control command value of an opening degree of a solenoid valve to control an opening degree of the solenoid valve; and an acquisition unit configured to acquire an estimated amount and a target amount of a working fluid in a labyrinth chamber, and a rotation speed of a drive shaft. The control unit calculates a final control command value based on a feedback control command value and a feedforward control command value, and controls the solenoid valve, the feedback control command value being calculated based on deviation between the estimated amount and the target amount, the feedforward control command value being used to maintain a rotation speed of a fan constant based on the estimated amount and the rotation speed of the drive shaft.

A controller of a fan coupling device includes: an acquisition unit that acquires an acceleration parameter and a deviation parameter; a control unit that controls a regulation mechanism; a prediction unit that predicts that hunting occurs in the rotation speed of the fan, when an operating point of the fan expressed with the deviation parameter and the acceleration parameter belongs to a predicted region; and a restraining unit that executes, when the hunting is predicted to occur, a hunting restraining process of executing at least one of lowering an integral gain of a feedback control to be lower than when the hunting is not predicted to occur and increasing a derivative gain of the feedback control to be higher than when the hunting is not predicted to occur.

A fluid friction clutch may include a rotatably mounted shaft, a drive disk arranged on the shaft in a rotationally fixed manner, a driven body rotatably arranged on the shaft, and a ring-shaped transfer region disposed between the drive disk and the driven body. The transfer region may be configured to receive a viscous fluid via which the drive disk is couplable to the driven body for transferring a torque. The transfer region may be defined by a ring-shaped first groove profile of the drive disk and a ring-shaped second groove profile of the driven body that engage one another axially. The clutch may also include a storage chamber fluidically connected to the transfer region via an inflow path and via a return path. The return path may include a first retaining body and a second retaining body arranged radially offset relative to one another by an arc angle.

A viscous clutch includes a housing, an input device rotationally fixed to the housing, a rotor, a working chamber, a reservoir, a valve, and a quick disconnect bushing. The housing has a base, a cover, and a housing hub connected in in a rotationally fixed configuration. The input device is a pulley, a sprocket, and/or a gear. The rotor has a rotor disk and a rotor hub connected in a rotationally fixed configuration, and a central opening extends entirely through the rotor hub. The reservoir is carried by the housing and overlaps the input device in an axial direction. The quick disconnect bushing is removably secured to the rotor hub at the central opening and permits a rotationally fixed engagement between the rotor and an item driven by the clutch, such as an output shaft.

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 coupling may include: a housing part and an input body rotatable relative to the housing part that at least partially delimit an interior space; a shaft rotatable relative to the housing part and on which an output body arranged in the interior space may be formed for conjoint rotation with the shaft; a coupling region formed between the output and input bodies and configured to hold a viscous fluid to assure a coupling between the input body and the output body; a holding chamber for collecting coolant leaking from the coolant pump; a housing wall conformed integrally with the housing part and partially delimiting the holding chamber; and an actuator housing and an electric actuator therein by which a degree of the coupling between the input body and the output body may be adjustable. The actuator housing may at least partially cover the holding chamber.

A clutch assembly includes a clutch mechanism and an energy harvesting device. The clutch mechanism includes an input member, an output member, and an actuating mechanism to govern selective torque transmission from the input member to the output member. The actuating mechanism is powered by electrical current. The energy harvesting device is electrically connected to the actuating mechanism, and the energy harvesting device is configured to scavenge available energy to generate the electrical current that powers the actuating mechanism.

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.