An electronic actuator according to the present invention comprises: a shaft; a bobbin; a nut; an upper bushing; a housing; a bearing; and a lower bushing. The shaft rotates by receiving a rotational force from an engine crank shaft. The bobbin is mounted to surround the middle portion of the shaft, wherein the bobbin has a coil wound inside thereof. The nut is made of a magnetic material and mounted to surround one side in the longitudinal direction of the shaft, while being screw-connected to a clutch. The upper bushing is made of as nonmagnetic material and is press-fit between the one side in the longitudinal direction of the shaft and the nut, so as to connect the shaft and the nut to form a single body. The housing is made of a magnetic material and comprises a bottom plate and a side wall to surround the other side in the longitudinal direction of the shaft, wherein the side wall extends to partially overlap the nut. The bearing is mounted on the outer peripheral surface on the other side in the longitudinal direction of the shaft, positioned inside the housing. The lower bushing is made of a nonmagnetic material and is press-fit between the bearing and the housing so as to connect the bearing and the housing to form a single body.

A viscous clutch according to the present invention, which is composed of a main body having a fluid storage chamber of a concave shape formed at a central portion thereof and a cover having a concave fluid operation chamber formed at a central portion thereof, comprises: a fan housing in which the main body is stacked on an upper side of the cover so that an opening of the fluid operation chamber can be covered; a drive shaft which extends in a vertical direction and has a lower end inserted through a bottom plate of the main body; a rotor fixedly coupled to the lower end of the drive shaft so as to be rotatable in the fluid operation chamber; a rotary assembly integrally coupled to the main body so as to cover an opening of the fluid storage chamber; a coil core mounted on an upper surface of the rotary assembly and generating an electromagnetic force when an electric current is applied from the outside; and a valve assembly for opening or closing a fluid outlet according to whether or not an electric current is applied to the coil core.

A viscous clutch according to the present invention, which is composed of a main body having a fluid storage chamber of a concave shape formed at a central portion thereof and a cover having a concave fluid operation chamber formed at a central portion thereof, comprises: a fan housing in which the main body is stacked on an upper side of the cover so that an opening of the fluid operation chamber can be covered; a drive shaft which extends in a vertical direction and has a lower end inserted through a bottom plate of the main body; a rotor fixedly coupled to the lower end of the drive shaft so as to be rotatable in the fluid operation chamber; a rotary assembly integrally coupled to the main body so as to cover an opening of the fluid storage chamber; a coil core mounted on an upper surface of the rotary assembly and generating an electromagnetic force when an electric current is applied from the outside; and a valve assembly for opening or closing a fluid outlet according to whether or not an electric current is applied to the coil core.

A control device for a dutch, which is provided between an operating machine and a drive shaft of an engine, controls the operation of a valve member for opening and closing an oil supply hole through which an oil reservoir chamber and a torque transmission chamber communicate. The control device refers to a target rotational speed of a rotational solid of the operating machine and to the acquired rotational speed of the rotational solid of the operating machine, calculates a proportional manipulated variable based on the deviation between the angular acceleration of the rotational solid and a target angular acceleration, and controls the operation of the valve member on the basis of this calculated proportional manipulated variable.

Provided is a fluid fan clutch with excellent cooling performance capable of effectively preventing, by very simple means, a decrease in the volume of air due to backflow of cooling fan air occurring when the fan clutch is activated. The fluid fan clutch has a structure with a fan removably fixed to a housing composed of a front-side housing component (cover) and a back-side housing component (case), wherein projecting parts for preventing backflow of fan air are arranged on the back-side housing component so as to be shifted in the circumferential direction with respect to fixing projections of the front-side housing component.

Provided is a fluid fan clutch with excellent cooling performance capable of effectively preventing, by very simple means, a decrease in the volume of air due to backflow of cooling fan air occurring when the fan clutch is activated. The fluid fan clutch has a structure with a fan removably fixed to a housing composed of a front-side housing component (cover) and a back-side housing component (case), wherein projecting parts for preventing backflow of fan air are arranged on the back-side housing component so as to be shifted in the circumferential direction with respect to fixing projections of the front-side housing component.

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.

An external control type fan clutch device has an electromagnet fixed to a rotating shaft. The electromagnet is energized to activate a valve member formed of a plate spring and an armature and provided to a drive disk or a sealed housing to externally control opening and closing an oil circulating flow passage (oil supply port). The valve member is structured so that the armature attached to the plate spring of the valve member is divided into a plurality of pieces in the direction from the base end side to the oscillating end side of the plate spring to provide a plurality of bend points of the plate spring.

A cooling control system includes a prime mover, a fan to be rotated under rotational power of an output shaft of the prime mover, a housing to which the fan is attached, a rotor to be rotated under rotational power of the prime mover, the rotor and the housing, under the agency of a fluid, rotating together, a fluid setting circuit to determine an injection quantity of the fluid to be introduced into the gap, a fan rotation detection device to detect a fan actual rotation speed, a target rotation obtaining circuit to obtain a fan target rotation speed. The integral controlling circuit does not execute the integral control with a difference between the fan actual rotation speed and a fan target rotation speed being greater than or equal to a threshold, and executes the integral control with the difference being less than the threshold.

A torque generating device includes a magnetic disk configured to rotate around a rotation axis, first and second yokes located on opposite sides across the magnetic disk, a coil disposed to overlap the magnetic disk along a direction of the rotation axis, a third yoke of which at least a region proximity to the magnetic disk is located outside the magnetic disk and the coil and that makes up a magnetic path of a magnetic field generated by the coil with the first and second yokes, and a magnetic viscous fluid filled between the magnetic disk and the first and second yokes. The third yoke has a magnetic gap between the third and first yokes. The magnetic gap is formed at a position outside an outer peripheral edge of the magnetic disk or overlapping the outer peripheral edge of the magnetic disk along the direction of the rotation axis.