JPH08177887A - Fan coupling - Google Patents

Abstract

PURPOSE: To efficiently recover viscosity fluid into a storing chamber with a simple structure so as to maintain its effect for a long time so as to cancel the function of a viscosity coupling when an engine is rotated with low speed. CONSTITUTION: An input shaft 16 and a rotor 17 are covered with a housing 18, and its housing 18 is rotated relatively with the input shaft 16 and the rotor 17. A fan 14 is mounted on the outer circumference of the housing 18. The inside of the housing 18 is partitioned into an operating chamber 28 and a storing chamber 30 by a partition board 27. A viscosity coupling 37 is provided to function by a viscosity fluid between the rotor 17 and the partition board 27 in the operating chamber 28. A communicating hole 40 for making the viscosity fluid flow from the operating chamber 28 into the storing chamber 30 is provided on the outer circumferential part of the partition board 27. An engaging means 41 is arranged on the outer circumferential part of the partition board 27 adjacently to the communicating hole 40. At the time of low speed rotation of the input shaft 16, the engaging means 41 is engaged with the rotor 17, the viscosity fluid is guided to the communicating hole 40. At the time of intermediate and high speed rotation of the input shaft 16, the engaging means 41 is moved on the basis of centrifugal force, and then, engaging of the rotor 17 of the means 41 is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan coupling applied to a cooling device or the like and configured to transmit a rotational torque of a drive source to a fan by using a viscous joint.

[0002]

2. Description of the Related Art Generally, a cooling device mounted on a vehicle or the like includes a radiator and a fan for cooling the radiator. In the type in which the fan is rotated by using the engine as a drive source, a fan coupling interposed between the engine output shaft and the fan transmits the rotational torque of the engine to the fan.

FIG. 6 shows an example of this type of fan coupling. The coupling 51 includes an input shaft 52 that receives a rotational torque from an engine output shaft (not shown) and a rotor 53 that is integrally rotatable with the input shaft 52. Further, the coupling 51 covers a part of the input shaft 52 and the rotor 53, and the input shaft 52 and the rotor 5
The housing 54 is provided so as to be rotatable relative to the housing 3. A fan 55 is mounted on the outer periphery of the housing 54. The viscous joint 56 provided between the rotor 53 and the housing 54 inside the housing 54 is
3, 54 are selectively connected. The viscous fluid enclosed inside the housing 54 for selectively operating the viscous joint 56 moves inside the housing 54 according to the magnitude of the engine rotation speed. That is, the partition plate 57 disposed inside the housing 54 partitions the internal space into the working chamber 58 and the storage chamber 59. When the viscous fluid is located in the working chamber 58, the viscous joint 56 functions and the rotational torque transmitted to the input shaft 52 is the rotor 53 and the viscous joint 5.
The fan 55 is transmitted to the housing 54 via 6 and rotates integrally. The viscous fluid is collected in the storage chamber 59 and the working chamber 5
When it is not located at 8, the viscous joint 56 does not function, the rotational torque transmitted to the input shaft 52 is not transmitted from the rotor 53 to the housing 54, and the fan 55 does not rotate.

By the way, in this type of coupling 51, when the output shaft of the engine rotates at a medium or high speed equal to or higher than a predetermined value, the fan 55 is rotated to cool the radiator so that the output shaft is less than the predetermined value. When rotating at low speed,
That is, when the engine is idling, the fan 55 is rotated at a low speed. When the engine shifts to the idling state, the viscous fluid in the working chamber 58 needs to be collected in the storage chamber 59 in order to rotate the fan 55 at a low speed. Communication hole 6 opened in the partition plate 57
0 stores the viscous fluid in the working chamber 58 at this time in the storage chamber 59.
Shed to. In this case, the viscous fluid flows into the communication hole 60 by the relative rotation between the rotor 53 and the partition plate 57 and the centrifugal force. Here, as shown in FIGS. 6 and 7, the protrusion 61 fixed to the partition plate 57 adjacent to the communication hole 60 guides the flow of the viscous fluid to the communication hole 60. However, even if there is such a protrusion 61, some gap G remains between the protrusion 61 and the rotor 53. Then, the amount of the fluid flowing through the communication hole 60 is reduced by the amount of the viscous fluid that escapes from the gap G, and the recovery of the viscous fluid in the storage chamber 59 tends to be delayed. Therefore, when the engine speed rises from the idling state when the vehicle starts, the viscous fluid remaining in the working chamber 58, which has not been recovered, acts on the viscous joint 56, and the fan 55 immediately starts rotating. The rotation caused noise when the vehicle started.

Therefore, in order to efficiently collect the viscous fluid into the storage chamber 59 through the communication hole 60, as shown in FIGS. 8 and 9, an elastic body 62 such as rubber is attached to the protrusion 61 and the protrusion 61 and the rotor 53. It is conceivable to fill the gap G of.

[0006]

However, as shown in FIGS. 8 and 9, if the elastic pair 62 is simply fixed to the protrusion 61, the elastic body 62 is always in contact with the rotor 53. Here, the elastic body 62 effectively exhibits its function when the viscous fluid in the working chamber 58 is collected in the storage chamber 59, that is, when the engine is idling. Therefore, in other cases, the contact of the elastic body 62 with the rotor 53 causes a problem only by promoting wear of the elastic body 62. If the elastic body 62 wears faster, the recovery efficiency of the viscous fluid in the storage chamber 59 decreases. On the other hand, as a measure against abrasion of the elastic body 62, it is possible to treat the contact surface of the rotor 53 with the elastic body 62 with a state having a small friction coefficient, for example, teflon coating. However, in this case, the outer peripheral surface of the rotor 53 must be precisely machined over the entire circumference.

The present invention has been made in view of the above-mentioned circumstances, and its object is to cancel the function of the viscous joint when the output shaft of the drive source rotates at a low speed on the premise of a fan coupling using the viscous joint. To provide a fan coupling that enables a viscous fluid to be efficiently recovered from the working chamber to the storage chamber with a relatively simple structure, and that can maintain its stable effect for a long period of time. It is in.

[0008]

In order to achieve the above object, in the present invention, an input shaft connected to an output shaft of a drive source, a rotor rotatable integrally with the input shaft, an input shaft, and A housing that covers the rotor and is rotatable relative to the input shaft and the rotor, and in which a fan is mounted,
A partition plate that partitions the internal space of the housing into a working chamber and a storage chamber and that is rotatable integrally with the housing,
A viscous joint that is provided between the rotor and the partition plate in the working chamber and that functions as a medium with the viscous fluid, and at least one communication that is provided on the outer periphery of the partition plate and that allows the viscous fluid to flow from the working chamber to the storage chamber. When a viscous fluid is located in the working chamber and acts on the viscous joint, the rotational torque transmitted to the input shaft is transmitted to the housing via the rotor and the viscous joint to rotate the fan and When the fluid is collected in the storage chamber and not located in the working chamber, the fan coupling is designed to cancel the transmission of the rotational torque transmitted to the input shaft from the rotor to the housing. When the output shaft is placed adjacent to the hole and rotates at a low speed below the specified value, it engages the rotor to guide the flow of viscous fluid to the communication hole, and the output shaft also moves to the specified value. And purpose in that a engagement means to disengage the rotor to move in a direction away from the rotor based on the centrifugal force acting on itself when rotating at high speed in the above.

[0009]

According to the above construction, when the output shaft of the drive source rotates at a low speed less than the predetermined value, the engaging means engages the rotor and the partition plate and the rotor are positioned adjacent to the communication hole. Is sealed and the viscous fluid is efficiently guided to the communication hole and collected in the storage chamber. Therefore, the viscous fluid does not remain in the working chamber, the transmission of the rotational torque transmitted to the input shaft from the rotor to the housing is canceled, and the fan rotates at a low speed. On the other hand, when the output shaft of the drive source rotates at a medium or high speed equal to or higher than a predetermined value, the engagement means moves in the direction away from the rotor due to the centrifugal force, and the engagement with the rotor is released.

Therefore, the engaging means engages with the rotor to function only when the viscous fluid is collected in the storage chamber, and does not engage with the rotor otherwise.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the fan coupling according to the present invention is applied to a vehicle cooling device will be described in detail below with reference to FIGS.

As shown in FIG. 5, an automobile 1 according to this embodiment.
1 is equipped with an engine 12 as a drive source, a radiator 13 and the like. The radiator 13 is one of the elements forming a cooling device for cooling the engine 12, and the engine 1
The cooling water circulated through 2 is introduced to radiate heat. The fan 14 arranged on the back side of the radiator 13 cools the radiator 13 by its rotation. The fan 14 is a type that rotates using the engine 12 as a drive source. A fan coupling (hereinafter simply referred to as "coupling") 15 interposed between the output shaft 12a of the engine 12 and the fan 14 connects the two shafts 12a and 14 to each other.
The rotational torque of a is selectively transmitted to the fan 14.

As shown in FIG. 1, this coupling 15
Includes an input shaft 16 connected to the output shaft 12a, and a rotor 17 fixed to the tip of the input shaft 16 and integrally rotatable with the coaxial shaft 16. Further, the coupling 15 covers the input shaft 16 and the rotor 17, and
The housing 18 is provided so as to be rotatable relative to 6 and 17. The fan 14 mounted on the outer periphery of the housing 18 is fixed by a plurality of bolts 19,
It is possible to rotate together with 8.

The case 20 and the cover 21 forming the housing 18 are fastened to each other by a plurality of bolts 22. A packing 23 for sealing is provided between the both 20 and 21. The case 20 is supported on the input shaft 16 via a bearing 24, so that the input shaft 1
It is possible to rotate relative to 6.

The first and second partition plates 26 and 27 fixed to the case 20 and the cover 21 by a plurality of screws 25 define the working space 28 inside the housing 18.
And the first and second storage chambers 29 and 30. Both partition plates 26 and 27 rotate integrally with the housing 18. A plurality of (only one is shown in FIG. 1) first communication holes 31 provided in the second partition plate 27 communicate between the working chamber 28 and the second storage chamber 30.

A valve plate 3 for opening and closing the first communication hole 31.
The center of 2 is attached to the cover 21 by a rod 33. The rod 33 is rotatably supported by the cover 21 via a bearing 34. A spiral bimetal 35 as a heat-sensitive member provided at the tip of the rod 33 is fixed to the cover 21.

The rotor 17 located in the working chamber 28 is provided with a second communication hole 36 corresponding to the first communication hole 31. The communication hole 36 is opened and closed by a valve member (not shown). This valve member opens based on the centrifugal force acting on itself when the rotation speed of the rotor 17 becomes a predetermined value or more, that is, when the rotation speed of the output shaft 12a of the engine 12 becomes a predetermined value or more. Here, the above-mentioned predetermined value relating to the rotation speed is set to a value slightly higher than the rotation speed value of the output shaft 12a in the idling state of the engine 12.

A second viscous joint 37 is provided in the working chamber 28 between the rotor 17 and the second partition plate 27.
A first viscous joint 38 is provided between the rotor 17 and the first partition plate 26. Both viscous joints 38 and 37 function using viscous fluid as a medium. This viscous fluid is previously sealed in the internal space of the housing 18, and can flow between the working chamber 28 and the storage chambers 29 and 30.

A plurality of third and fourth communication holes 39 and 40 are provided on the outer peripheral portions of the first and second partition plates 26 and 27, respectively. The third communication hole 39 allows the flow of the viscous fluid between the working chamber 28 and the first storage chamber 29. The fourth communication hole 40 allows the flow of the viscous fluid from the working chamber 28 to the second storage chamber 30. Here, when the viscous fluid is located in the working chamber 28 and acts on both viscous joints 38 and 37, the rotational torque transmitted to the input shaft 16 is transmitted to the housing via the rotor 17 and both viscous joints 38 and 37. 18 and the fan 14 is rotated. On the other hand, when the viscous fluid is collected in the second storage chamber 30 and is not located in the working chamber 28,
The rotational torque transmitted to the input shaft 16 is not transmitted from the rotor 17 to the housing 18.

In the coupling 15 of this embodiment, the fan 14 is rotated to cool the radiator 13 when the output shaft 12a rotates at a medium or high speed of a predetermined value or more,
When the output shaft 12a rotates at a low speed less than a predetermined value, that is, when the engine 12 is in an idling state, the fan 14 is rotated at a low speed. Therefore, when the engine 12 shifts to the idling state, in order to rotate the fan 14 at a low speed, the viscous fluid in the working chamber 28 is changed to the second state.
It is necessary to collect it in the storage room 30 of. Both partition plates 26, 2
Each communication hole 39, 40 provided in 7 functions at this time to finally flow the viscous fluid in the working chamber 28 to the second storage chamber 30. In this case, the rotor 17 and each partition plate 2
The viscous fluid passes through the communication holes 39 and 40 by the relative rotation with respect to 6 and 27 and the centrifugal force.

The engaging means 41 arranged adjacent to the fourth communication hole 40 on the outer peripheral portion of the second partition plate 27 has a movable projection 42 and an elastic body 43 fixed to one side surface of the movable projection 42. And a biasing member 44 for biasing the movable protrusion 42.
And As the movable protrusion 42, for example, a metal plate or the like can be applied. As the elastic body 43, for example, rubber or the like can be applied. As the biasing member 44, for example, a coil spring or a leaf spring can be applied. As shown in FIG. 2, in this embodiment, three fourth communication holes 40 are formed in the outer peripheral portion of the second partition plate 27 at equal angular intervals. Three engaging means 41 are provided corresponding to each communication hole 40. As shown in FIGS. 1 to 3, the biasing member 44 biases the movable protrusion 42 toward the center of the housing 18. This urging force causes the movable projection 42 to move.
Is arranged in a working position close to the second viscous joint 37,
In this state, the elastic body 43 engages with one side surface of the rotor 17. The elastic body 43 and the movable projection 42 are used to remove viscous fluid
Functioning as a guide to the communication hole 40. Here, when the output shaft 12a rotates at a low speed less than a predetermined value, the movable projection 42 and the elastic body 43 resist the centrifugal force acting on the both 42, 43 based on the urging force of the urging member 44. As shown in FIG. 3, the elastic body 43 and the rotor 17 are arranged at an operating position where they engage with each other. When the output shaft 12a rotates at a medium or high speed equal to or higher than a predetermined value, the movable protrusion 42 and the elastic body 43 resist the urging force of the urging member 44 based on the centrifugal force, so that the rotor 17 is moved from the rotor 17 as shown in FIG. When the elastic body 43 and the rotor 17 are disengaged, the elastic body 43 and the rotor 17 are disengaged.

On the other hand, the projection 45 formed adjacent to the third communication hole 39 on the outer peripheral portion of the first partition plate 26 allows the viscous fluid in the first storage chamber 29 to pass through the third communication hole 39.
I will guide you to.

Next, the operation of the coupling 15 constructed as described above will be described below. When the engine 12 starts and its output shaft 12a starts to rotate, the coupling 15
The input shaft 16 starts to rotate. At this time, the viscous fluid located in the first storage chamber 29 is guided to the third communication hole 39 by the protrusion 45 and flows into the working chamber 28. Further, the viscous fluid located in the working chamber 28 is guided to the fourth communication hole 40 by the engaging means 41 and flows into the second storage chamber 30, and most of it is collected in the second storage chamber 30. Here, when the engine 12 is not sufficiently warmed up, the automobile 1
Since the temperature of the air passing through the radiator 13 is low during traveling of No. 1 and the bimetal 35 does not deform, the valve plate 32 keeps the first communication hole 31 closed.

When the engine 12 warms up while the automobile 11 is running, the temperature of the air passing through the radiator 13 also rises. Therefore, the bimetal 35 is deformed and the valve plate 32 is displaced, and the valve plate 32 opens the first communication hole 31. Here, when the rotation speed of the input shaft 12a is a low speed less than a predetermined value, a very large centrifugal force does not act on the valve member related to the second communication hole 36, so that the valve member communicates with the second communication hole 36. The hole 36 remains closed. Further, since a large centrifugal force does not act on the movable protrusion 42 and the elastic body 43, the elastic body 43 remains engaged with the rotor 17. And the second
Of the viscous fluid located in the storage chamber 30 of the first communication hole 3
1 to the working chamber 28 and is supplied only to the second viscous joint 37. Therefore, the rotational torque transmitted to the rotor 17 is transmitted to the housing 18 via the second viscous joint 37 and the second partition plate 27, and the fan 14 rotates.

Here, the viscous fluid that has flowed into the second viscous joint 37 moves to the outermost peripheral portion of the working chamber 28 due to the centrifugal force acting on the second viscous joint 37, and again through the fourth communication hole 40 to the second communicating hole 40.
Flows to the storage room 30 of. That is, the viscous fluid is the first and the fourth
It circulates between the working chamber 28 and the second storage chamber 30 through the communication holes 31 and 40.

On the other hand, the valve member opens the second communication hole 36 when the rotation speed of the input shaft 12a reaches a medium or high speed equal to or higher than a predetermined value while the first communication hole 31 is open. Further, a certain amount of centrifugal force acts on the movable protrusion 42 and the elastic body 43. Therefore, as shown in FIG. 4, the movable protrusion 42 and the elastic body 43 move to the non-acting position, and the elastic body 43 moves to the rotor 17 side.
Move away from Therefore, the viscous fluid in the second storage chamber 30 flows into the working chamber 28 through the first communication hole 31, and the fluid is supplied to both the first and second viscous joints 38 and 37.

Therefore, the rotational torque transmitted to the rotor 17 is determined by the first and second viscous joints 38, 37 and the first and second viscous joints.
The fan 14 is rotated by being transmitted to the housing 18 through the partition plates 26 and 27 of the. Here, the viscous fluid that has flowed to the first and second viscous joints 38 and 37 moves to the outermost peripheral portion of the working chamber 28 due to the centrifugal force that acts on the same fluid, and again to the fourth
Through the communication hole 40 of the second storage chamber 30. That is, the viscous fluid is the first, second, and fourth communication holes 31, 36, 40.
Through the working chamber 28 and the second storage chamber 30.

By the way, the coupling 15 of this embodiment
Then, when the vehicle 11 is stopped once and the engine 12 is in the idling state, the viscous fluid in the working chamber 28 is collected in the second storage chamber 30 in order to rotate the fan 14 at a low speed. In this idling state, that is, in a state in which the output shaft 12a of the engine 12 rotates at a low speed less than a predetermined value, the movable projection 42 and the elastic body 43 are arranged in the operating position, and the elastic body 43 is Engage the rotor 17. Then, at a position adjacent to the fourth communication hole 40, the space between the second partition plate 27 and the rotor 17 is sealed. Therefore, most of the viscous fluid flowing near the fourth communication hole 40 is moved to the fourth position by the movable protrusion 42 and the elastic body 43.
And is collected in the second storage chamber 30. Therefore, the viscous fluid does not remain in the working chamber 28, and the second viscous joint 37 does not function with the viscous fluid. Alternatively, the working chamber 28 does not have enough viscous fluid left to contribute to the function of the second viscous joint 37. Then, the rotor 17 of the rotational torque transmitted to the input shaft 12a
Is canceled to the housing 18, and the fan 14 rotates at a low speed. As a result, when the vehicle 11 restarts and the rotation speed of the output shaft 12a of the engine 12 rises from the idling state, the fan 14 does not immediately start rotating at high speed, and the fan 14 does not rotate at the time of starting. There is no noise generated.

Further, in the coupling 15 of this embodiment,
When the output shaft 12a rotates at a medium or high speed equal to or higher than a predetermined value, the movable protrusion 42 and the elastic body 43 are separated from the rotor 17, and the engagement between the rotor 17 and the elastic body 43 is released. Therefore, the elastic body 43 engages with the rotor 17 only when the viscous fluid is collected in the second storage chamber 30, and does not engage with the rotor 17 in other cases. Therefore, the sliding contact time between the elastic body 43 and the rotor 17 is reduced, and the opportunity for the elastic body 43 to wear is reduced.

Therefore, according to the coupling 15 of this embodiment, the viscous fluid can be efficiently moved from the working chamber 28 to the second storage chamber 30 and collected only when the engine 12 rotates at a low speed. This can be achieved by the relatively simple structure of the movable protrusion 42, the elastic body 43, and the biasing member 44. As a result, it is not necessary to perform a precise surface treatment on the contact surface of the rotor 17 with the elastic body 43 to reduce the wear of the elastic body 43. Moreover, the stable effect of the elastic body 43 can be maintained for a longer period because the elastic body 43 is less worn.

Further, in this embodiment, when the rotor 17 rotates at medium and high speeds, the rotor 17 and the elastic body 43 do not come into contact with each other, so that the contact resistance between the rotor 17 and the elastic body 43 is eliminated and the fan 14 is driven. The loss can be reduced.

In addition, in this embodiment, since the engaging means 41 and the rotor 17 are engaged with each other by the elastic body 43 such as rubber, mechanical contact between the both 41, 17 is prevented by the elastic body 4.
It can also be buffered by 3.

The present invention can be embodied in the following other embodiments. In another example below,
It is possible to obtain the same actions and effects as those of the above-mentioned embodiment. (1) In the above embodiment, the coupling 15 of the type in which the two storage chambers 29 and 30 and the two viscous couplings 38 and 37 are provided for one working chamber 28 is embodied. On the other hand, it is also possible to embody a type of coupling in which one storage chamber and one viscous joint are provided for one working chamber.

(2) In the above embodiment, the three communication holes 4 for flowing the viscous fluid from the working chamber 28 to the second storage chamber 30.
0 is provided, and three engaging means 41 are provided accordingly. On the other hand, the number of communication holes and the number of engaging means may be one, or two, four, or more.

(3) In the above embodiment, the movable projection 42 and the elastic body 43 are composed of separate members.
43 may be configured of the same member. For example, the entire movable protrusion may be made of a thick elastic body so that it can be engaged with the rotor.

Furthermore, it will be described below together with the effect that each of the above-described embodiments includes various embodiments related to the technical idea described in the claims as follows. (A) In the invention according to claim 1, a fan coupling in which a portion of the engaging means that engages with the rotor is made of an elastic body.

According to this structure, the mechanical contact between the engaging means and the rotor can be buffered by the elastic body. In this specification, means and the like relating to the constitution of the invention are defined as follows.

(A) A drive source means a power source for giving a rotational torque to a fan, an automobile means an engine, and an electric motor and the like. (B) The viscous joint means one that transmits torque by utilizing the shear of a highly viscous viscous fluid (such as silicone oil), and includes a viscous coupling.

[0039]

According to the invention described in claim 1, in the fan coupling using the viscous joint, the engaging means is arranged adjacent to the communication hole in the outer peripheral portion of the partition plate. Then, when the output shaft of the drive source rotates at a low speed lower than a predetermined value, the engaging means is engaged with the rotor to guide the flow of the viscous fluid to the communication hole and collect the viscous fluid in the storage chamber. Then
When the output shaft rotates at a medium or high speed equal to or higher than a predetermined value, the engagement means is moved away from the rotor based on the centrifugal force acting on the output shaft to release the engagement with the rotor.

Therefore, the engaging means engages with the rotor to function only when the viscous fluid is collected in the storage chamber, and does not engage with the rotor otherwise. As a result, since the function of the viscous joint is canceled when the output shaft rotates at a low speed, the viscous fluid can be efficiently collected in the storage chamber with a relatively simple structure, and the stable effect can be maintained for a long period of time. The effect of being able to do is exhibited.

[Brief description of drawings]

FIG. 1 is a sectional view of a fan coupling according to an embodiment.

FIG. 2 is an explanatory view showing an arrangement of engaging means and the like on a partition plate according to an embodiment.

FIG. 3 is an explanatory view showing the action of the engaging means according to the embodiment.

FIG. 4 is an explanatory view showing the action of the engaging means according to the embodiment.

FIG. 5 is a conceptual diagram showing an arrangement of automobile fans according to one embodiment.

FIG. 6 is a partial cross-sectional view of a conventional fan coupling.

FIG. 7 is an explanatory view showing the action of the protrusions in the fan coupling of FIG.

FIG. 8 is a partial cross-sectional view of another prior art fan coupling.

9 is an explanatory view showing the action of a protrusion in the fan coupling shown in FIG.

[Explanation of symbols]

12 ... Engine as drive source, 12a ... Output shaft, 14
... fan, 16 ... input shaft, 17 ... rotor, 18 ... housing, 27 ... second partition plate, 28 ... working chamber, 30 ... second
Storage chamber, 40 ... Fourth communication hole, 41 ... Engaging means, 42
... Movable protrusion, 43 ... Elastic body, 44 ... Biasing member.

Claims (1)

[Claims] 1. A fan coupling for connecting an output shaft of a drive source and a fan to transmit rotational torque of the output shaft to the fan, the input shaft being connected to the output shaft of the drive source. A rotor that can rotate integrally with the input shaft; a housing that covers the input shaft and the rotor and is rotatable relative to the input shaft and the rotor, and in which the fan is mounted; And a partition plate that divides the partition into a working chamber and a storage chamber and is rotatable integrally with the housing, and a viscous fluid that is provided between the rotor and the partition plate in the working chamber and that functions with a viscous fluid as a medium. A joint and at least one communication hole provided on an outer peripheral portion of the partition plate for flowing the viscous fluid from the working chamber to the storage chamber; When a viscous fluid is located and acts on the viscous joint, the rotational torque transmitted to the input shaft is transmitted to the housing via the rotor and the viscous joint to rotate the fan, In a fan coupling configured to cancel the transmission of the rotational torque transmitted to the input shaft from the rotor to the housing when the gas is collected in the storage chamber and is not located in the working chamber. Is arranged adjacent to the communication hole at the outer peripheral portion of the rotor, and engages the rotor to guide the flow of the viscous fluid to the communication hole when the output shaft rotates at a low speed less than a predetermined value. , When the output shaft rotates at a medium or high speed equal to or higher than a predetermined value, it disengages from the rotor by moving in the direction away from the rotor based on the centrifugal force acting on the output shaft. A fan coupling, characterized in that it is provided with engaging means.