JP2021011867A - Fan device - Google Patents

Abstract

To improve fan efficiency while improving cooling performance of components.SOLUTION: In a fan device 1, a housing 10 has a first housing 11 and a second housing 12 disposed in an axis x direction, and a motor base portion 120 of the second housing 12 formed into a cylindrical shape and covering a motor 20 from a lower side in the axis x direction, has a base main body portion 121 extended in a radial direction and covering the motor 20 from a lower side in the axis x direction, and a base outer peripheral wall portion 124 extended from an end portion of the base main body portion 121 toward an upper side from a lower side in the axis x direction. A hub 27 has a hub main body portion 272 as a face extended in the radial direction orthogonal to the axis x direction and covering the motor 20 from an upper side a in the axis x direction, and a hub outer peripheral wall portion 271 extended from an end portion of the hub main body portion 272 toward a lower side from an upper side in the axis x direction, and 1.05<b1/a1<1.13 is established when a diameter of an outer peripheral face of the hub outer peripheral wall portion 271 is a1, and a diameter of an outer peripheral face of the base outer peripheral wall portion 124 is b1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fan device.

Fan devices include axial fans that are widely used in applications such as cooling, ventilation, air conditioning, and ventilation in electronic devices, home appliances, OA devices, industrial devices, and vehicles. As an axial fan, for example, a pillow portion having a pillow portion on the fan base forms a vent and a flow path on the opposite side of the imperabos, so that a part of the air flow by the fan is introduced into the imperabos. A fan heat dissipation structure that dissipates heat from the entire motor is known (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-177309

By the way, in the fan device, a circuit board is provided inside a motor base portion on which a motor for rotating an impeller is mounted. The circuit board is equipped with electronic components for forming a control circuit that controls the operation of the motor. In the conventional fan device, the circuit board is mounted on the motor base portion so as not to protrude outward in the radial direction from the outer circumference of the hub of the impeller so as not to obstruct the air flow generated by the rotation of the impeller.

However, when mounted in the motor base portion as described above, a sufficient air flow is not introduced into the inside of the motor base portion in the circuit board in the conventional fan device. For this reason, in the conventional fan device, when the heat generated by the electronic components mounted on the circuit board increases, the heat is trapped inside the motor base portion, and the temperature of the circuit board rises. As a result, the fan device can be used as a fan device. There was a problem that the life was shortened.

Further, in the heat dissipation structure of the fan described in Patent Document 1, the pillow portion provided on the fan base as the motor base portion forms a vent and a flow path on the opposite side of the imperabos as the hub, so that the impeller can be formed. A part of the air flow generated by rotation was introduced into the imperabos to dissipate heat from the motor.

However, in the structure described in Patent Document 1, the outer circumference of the pillow portion protrudes outward in the radial direction from the outer circumference of the hub of the impeller. Therefore, in the structure described in Patent Document 1, when the protrusion of the pillow portion is increased to promote heat dissipation of the motor, the air flow is obstructed, and as a result, the air flow is discharged from the exhaust port of the housing. There was a problem that the air volume decreased and the fan efficiency decreased.

The present invention is an example of the above-mentioned problems, and an object of the present invention is to provide a fan device capable of improving fan efficiency while improving cooling performance of components.

In order to achieve the above object, the fan device according to the present invention includes a hub, an impeller having a plurality of blades provided on the hub, a motor for rotating the impeller, and a housing accommodating the impeller. The housing is formed in a cylindrical shape and has a motor base portion that covers the motor from the lower side in the axial direction, and the motor base portion is a surface extending in a radial direction orthogonal to the axial direction. The hub has a base main body portion that covers the motor from the lower side in the axial direction, and a base outer peripheral wall portion that extends from the lower side to the upper side in the axial direction from the end portion of the base main body portion. A surface extending in the radial direction orthogonal to the axial direction, the hub main body portion covering the motor from the upper side in the axial direction, and the outer periphery of the hub extending from the upper end to the lower side in the axial direction from the end portion of the hub main body portion. 1.05 <b1 / a1 <1.13 when the diameter of the outer peripheral surface of the hub outer peripheral wall portion is a1 and the diameter of the outer peripheral surface of the base outer peripheral wall portion is b1. is there.

In the fan device according to one aspect of the present invention, the diameter of the inner peripheral surface of the base outer peripheral wall portion is larger than the diameter of the outer peripheral surface of the hub outer peripheral wall portion over the entire circumference.

In the fan device according to one aspect of the present invention, the hub main body has an exhaust hole penetrating in the axial direction.

In the fan device according to one aspect of the present invention, a gap portion is provided between the inner peripheral surface of the motor base portion and the outer peripheral surface of the hub.

In the fan device according to one aspect of the present invention, the housing has a first housing and a second housing arranged in the axial direction, and the first housing is an intake port opened on the upper side of the impeller. The second housing has an exhaust port that is open to the lower side of the impeller, and a part of the air flow from the intake port to the exhaust port due to the rotation of the impeller is described as described above. It is introduced into the inside of the motor base portion from the gap portion.

According to the fan device according to the present invention, it is possible to improve the fan efficiency while improving the cooling performance of the components.

It is sectional drawing which shows schematic the structure of the fan apparatus which concerns on embodiment of this invention. FIG. 5 is an enlarged cross-sectional view schematically showing the configuration of the fan device shown in FIG. FIG. 5 is a schematic view schematically showing the relationship between the diameter of the outer peripheral wall portion of the base and the diameter of the outer peripheral wall portion of the hub in the fan device shown in FIG. FIG. 5 is an enlarged cross-sectional view schematically showing an air flow in the fan device shown in FIG. 6 is a graph showing the relationship between the ratio of the outer diameter of the motor base portion to the outer diameter of the hub and the fan efficiency in the fan device shown in FIG. FIG. 5 is an enlarged cross-sectional view schematically showing a configuration of a fan device according to another embodiment of the present invention.

Hereinafter, the fan device 1 according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a configuration of a fan device 1 according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view schematically showing the configuration of the fan device 1 shown in FIG.

In the following description, for convenience, the arrow a direction is the upper side a and the arrow b direction is the lower side b in the axis x direction. Further, in the radial direction perpendicular to the axis x, the direction away from the axis x (direction of arrow c in FIG. 1) is defined as the outer peripheral side c, and the direction toward the axis x (direction of arrow d in FIG. 1) is defined as the inner peripheral side d. .. In the following description, for convenience, the direction shown in FIG. 1 is referred to as the side surface of the fan device 1. Further, in the following description, for convenience, the direction in which the fan device 1 is viewed from the upper side a toward the lower side b is the front surface, and the direction in which the fan device 1 is viewed from the lower side b toward the upper side a is the bottom surface.

As shown in FIGS. 1 and 2, the fan device 1 according to the present embodiment includes a motor 20 for rotating the shaft 15, an impeller 25 mounted on the shaft 15, and a housing 10 for accommodating the impeller 25. To be equipped. The impeller 25 covers the motor 20 from the upper side a in the axis x direction and has a hub 27 and a plurality of blades 28 provided on the hub 27. The second housing 12 of the housing 10 has a motor base portion 120 which is formed in a cylindrical shape and covers the motor 20 from the lower side b in the axis x direction. The motor base portion 120 is a surface extending in the radial direction orthogonal to the axis x direction, and is a base main body portion 121 that covers the motor 20 from the lower side b in the axis x direction and a lower portion in the axis x direction from the end of the base main body portion 121. It has a base outer peripheral wall portion 124 extending from the side b toward the upper side a. The hub 27 is a surface extending in the radial direction orthogonal to the axis x direction, from the hub body 272 covering the motor 20 from the upper side a in the axis c direction, and from the upper side a in the axis x direction from the end of the hub body 272. When the hub outer peripheral wall portion 271 extending toward the lower side b is provided, the outer diameter of the outer peripheral surface of the hub outer peripheral wall portion 271 is a1, and the outer diameter of the outer peripheral surface of the base outer peripheral wall portion 124 is b1. 1.05 <b1 / a1 <1.13. Hereinafter, the configuration and operation of the fan device 1 will be specifically described.

[Fan device configuration]
The fan device 1 includes a motor 20, an impeller 25, a first housing 11, and a second housing 12 as main components.

The impeller 25 is arranged about the axis x inside the first housing 11 and the second housing 12. The impeller 25 has a cup-shaped hub 27 formed in a cylindrical or substantially cylindrical shape that is open toward the lower side b, and a hub outer peripheral wall portion 271 provided on the outer peripheral surface of the hub 27 in the circumferential direction. It has a plurality of (for example, five) blades 28 facing toward it, and all the blades 28 have the same shape and are arranged at equal intervals in the circumferential direction. In the impeller 25, the hub 27 and the blade 28 are integrally molded with resin.

The impeller 25 is adhered to the rotor yoke 40 with, for example, an adhesive. The impeller 25 has first exhaust holes 32 as a plurality of openings penetrating in the axis x direction on the upper surface a of the hub main body portion 272 of the hub 27. The rotor yoke 40 is formed with a second exhaust hole 41 penetrating in the axis x direction at the same position as the first exhaust hole 32 in the radial direction. In the fan device 1, the first exhaust hole 32 and the second exhaust hole 41 form an exhaust hole that allows air flow to flow inside and outside the impeller 25. Further, the impeller 25 is provided with an opening 33 at the radial center of the hub main body 272 through which a part of the bush 35 connected to the shaft 15 can be passed.

The rotor yoke 40 may be integrally molded with the impeller 25 by insert molding.

The motor 20 includes a stator 13 that is fixedly attached to the second housing 12 side and a rotor 24 that is attached to the impeller 25 side.

The rotor 24 includes a shaft 15 provided at the center of the hub 27 with the axis x direction as the longitudinal direction via the bush 35, a rotor yoke 40 provided along the inner peripheral surface 27a of the hub 27, and a rotor yoke 40. A magnet 26 provided on the inner peripheral side d of the above is provided. The rotor yoke 40 is provided with an insertion hole 43 at the center in the radial direction through which a bush 35 to which the shaft 15 is connected can be inserted. The rotor yoke 40 is caulked and fixed to the bush 35.

The stator 13 mainly includes an insulator 16, a bearing holder 17, a stator core 18, a coil 19, and a bearing 22.

The insulator 16 is mounted from both sides of the upper side a and the lower side b in the axial direction of the stator core 18. The bearing holder 17 is attached to the boss portion 125 of the second housing 12. The bearing holder 17 is a hollow cylindrical member made of metal (for example, brass). The bearing holder 17 is attached to a resin boss portion 125 by an appropriate method such as press fitting. A pair of bearings 22 that rotatably support the shaft 15 and a coil spring 23 for applying a preload to the bearing 22 on the lower side b are mounted in the space of the inner peripheral portion of the bearing holder 17.

The stator core 18 is mounted on the outer circumference of the bearing holder 17. A donut-shaped circuit board 21, for example, is attached to the lower side b of the stator core 18. The circuit board 21 is equipped with electronic components that constitute a control circuit that controls the operation of the motor 20 in the fan device 1. The stator core 18 is formed by laminating a plurality of cores made of a soft magnetic material (for example, an electromagnetic steel plate) in the axis x direction. The stator core 18 has a plurality of salient poles extending radially outward from the annular portion.

The coil 19 is wound around each salient pole of the stator core 18 via an insulator 16. A circuit board 21 is attached to the lower side b of the insulator 16. The circuit board 21 is housed inside the motor base portion 120.

The first housing 11 is located on the intake side of the fan device 1, that is, on the upper side a in the axis x direction. The second housing 12 is located on the exhaust side of the fan device 1, that is, on the lower side b in the axis x direction. The first housing 11 and the second housing 12 are combined to form one housing for accommodating the motor 20 and the impeller 25, which are the components of the fan device 1 described above. The fan device 1 has a two-body structure that connects the first housing 11 and the second housing 12 to form the housing 10. Therefore, the first housing 11 and the second housing 12 have a high degree of freedom in shape when molding a complicated shape, for example, the shape of the inner peripheral surface and the shape of the fixed wing 123 by using a mold. Can be done.

The first housing 11 is formed so as to surround the impeller 25 from the outer peripheral side c. The first housing 11 has an intake port 111, a joint portion 112, and an inner peripheral portion 113.

The intake port 111 opens in the upper a direction of the impeller 25 in order to take air into the impeller 25. The intake port 111 is provided with an inclined surface that communicates with the inner peripheral portion 113 and increases in diameter from the lower side b toward the upper side a. The joint portion 112 is formed in a shape that can be joined to the joint portion of the second housing 12 described later, and the first housing 11 and the second housing 12 function as one housing as described above.

The inner peripheral portion 113 is a peripheral surface of the first housing 11 facing the impeller 25. The inner peripheral portion 113 is formed with an inclined surface at a portion facing the intake port 111 side of the upper side a of the first housing 11 and a portion facing the upper side a of the second housing 12 described later near the joint portion 112. Has been done. The portion of the inner peripheral portion 113 facing the upper side a of the second housing 12 is formed so as to increase the diameter of the portion continuous with the inclined surface.

The second housing 12 is formed in a shape that surrounds the circuit board 21 from the outer peripheral side c. The second housing 12 includes a motor base portion 120, a base main body portion 121, an exhaust port 122, a fixed wing 123, a base outer peripheral wall portion 124, a joint portion 126, an inner peripheral portion 127, and a substrate accommodating portion 128.

The motor base portion 120 covers the motor 20 from the lower side b in the axis x direction. The motor base portion 120 extends from the base main body portion 121 formed by a surface extending in the radial direction orthogonal to the axis x direction and the end portion of the base main body portion 121 from the lower side b in the axis x direction toward the upper side a. It has a vertical wall-shaped base outer peripheral wall portion 124 formed as described above. The base main body 121 is formed in a circular shape or a substantially circular shape centered on the axis x. The motor base portion 120 is formed in a cylindrical shape or a substantially cylindrical shape that is open toward the upper side a, with the base main body portion 121 as the bottom surface and the base outer peripheral wall portion 124 as the side surface. The motor base portion 120 has a substrate accommodating portion 128 capable of accommodating the circuit board 21 formed on an inner peripheral surface having a cylindrical or substantially cylindrical shape.

FIG. 2 is an enlarged cross-sectional view schematically showing the configuration of the fan device 1 shown in FIG. Further, FIG. 3 is a schematic view schematically showing the relationship between the diameter (outer diameter b1, inner diameter b2) of the base outer peripheral wall portion 124 and the diameter (outer diameter a1) of the hub outer peripheral wall portion 271 in the fan device 1. ..

As shown in FIGS. 2 and 3, in the motor base portion 120, the outer diameter b1 of the base outer peripheral wall portion 124 is larger than the diameter of the outer peripheral surface of the hub outer peripheral wall portion 271 of the hub 27 of the impeller 25, that is, the outer diameter a1. large. Further, the base outer peripheral wall portion 124 has a predetermined thickness in the radial direction, but the diameter of the inner peripheral portion 124a, that is, the inner diameter b2 is also larger than the outer diameter a1 of the hub outer peripheral wall portion 271. Here, the motor base portion 120 and the hub 27 of the impeller 25 are formed in a cylindrical shape or a substantially cylindrical shape as described above. Therefore, the inner diameter b2 of the base outer peripheral wall portion 124 is larger than the outer diameter a1 of the hub outer peripheral wall portion 271 over the entire circumference around the axis x.

The fan device 1 has an inner peripheral surface of the base outer peripheral wall portion 124 of the motor base portion 120 and a hub outer peripheral wall due to the difference between the outer diameter b1 and the inner diameter b2 of the base outer peripheral wall portion 124 and the outer diameter a1 of the hub outer peripheral wall portion 271. A gap portion G is formed between the portion 271 and the portion 271. As shown in FIG. 2, the gap G is open toward the upper side a of the fan device 1, that is, the intake port 111 side. Therefore, a part of the air flow sent toward the exhaust port 122 by the blades 28 of the impeller 25 is introduced into the substrate accommodating portion 128 formed on the inner peripheral side d of the gap portion G.

The exhaust port 122 opens in the upper a direction of the impeller 25 in order to exhaust the air taken into the housing 10 from the intake port 111 to the outside of the fan device 1. The exhaust port 122 communicates with the inner peripheral portion 113 of the first housing 11 and the inner peripheral portion 127 of the second housing 12. The joint portion 126 is formed in a shape that can be joined to the joint portion 112 of the first housing 11, and the first housing 11 and the second housing 12 function as one housing as described above.

A plurality of fixed wings 123 are formed on the outer peripheral surface of the motor base portion 120 which is formed in a circular shape or a substantially circular shape on the exhaust port 122 side of the lower side b of the second housing 12. The fixed wing 123 extends from the outer peripheral surface of the motor base portion 120 to the outer peripheral side c in the radial direction and is coupled to the inner peripheral portion 127 of the second housing 12. The second housing 12, the motor base portion 120, and the fixed wing 123 are integrally formed of resin.

The inner peripheral portion 127 is a peripheral surface facing the impeller 25 in the second housing 12. The inner diameter of the inner peripheral portion 127 has the same diameter in the axis x direction. The inner peripheral portion 127 of the second housing 12 has a diameter larger than the diameter of the inner peripheral portion 113 of the first housing 11 in which the blade 28 of the impeller 25 rotates. The fan device 1 increases the pressure (static pressure) by increasing the diameters of the inner peripheral portions 113 and 127 from the intake port 111 toward the exhaust port 122.

[Operation of fan device]
Next, the operation of the fan device 1 having the configuration described above will be described.

FIG. 4 is an enlarged cross-sectional view schematically showing the air flow in the fan device 1. As shown in FIG. 4, the motor 20 rotationally drives the impeller 25 by rotating the rotor 24 with respect to the stator 13. As the impeller 25 is rotated by the motor 20, the plurality of blades 28 provided on the impeller 25 are opened from the intake port 111 of the first housing 11 to the lower side of the second housing 12 which are open on the upper side a of the impeller 25. An air flow is generated that is discharged to the outside through between the fixed blades 123 toward the exhaust port 122 that is open to b.

The outer diameter b1 of the motor base portion 120 is formed to be larger than the outer diameter a1 of the hub outer peripheral wall portion 271 of the hub 27 in the impeller 25. Further, the inner diameter b2 of the motor base portion 120 is formed to be larger than the outer diameter a1 of the hub outer peripheral wall portion 271 of the hub 27 in the impeller 25. Therefore, in the fan device 1, among the air flows F1 and F2 discharged from the exhaust port 122 through the blades 28 by the rotation of the impeller 25, the air flow F2 flowing along the hub outer peripheral wall portion 271. A part of the portion is introduced from the gap portion G into the inside of the substrate accommodating portion 128 of the motor base portion 120. Then, in the fan device 1, the electronic components mounted on the circuit board 21 are cooled by the air flow F2 introduced in the motor base portion 120, and heat dissipation is promoted.

FIG. 5 is a graph showing the relationship between the ratio b1 / a1 of the outer diameter b1 of the motor base portion 120 to the outer diameter a1 of the hub 27 and the fan efficiency E in the fan device 1. The fan efficiency E is shown as a ratio based on the fan efficiency E when the ratio b1 / a1 of the outer diameter b1 of the motor base portion 120 to the outer diameter a1 of the hub 27 is 1.

As shown in FIG. 5, when the ratio b1 / a1 is between 1 and 1.05, the fan efficiency E hardly changes. On the other hand, when the ratio b1 / a1 becomes 1.05 or more, the fan efficiency E improves, and when the ratio b1 / a1 is about 1.105, the fan efficiency E shows the maximum value. The fan efficiency E decreases after showing the maximum value, and when the ratio b1 / a1 reaches the position of about 1.13, the ratio b1 / a1 shows 1 to 1.05, which is almost the same value as before the change.

As described above, in the fan device 1, the range of the ratio b1 / a1 that can improve the fan efficiency E is 1.05 <b1 / a1 <1.13. Preferably, in the fan device 1, by setting 1.09 <b1 / a1 <1.12, the cooling of the circuit board 21 can be enhanced and the fan efficiency E can be improved.

In the fan device 1, in order to form a gap G for introducing an air flow into the substrate accommodating portion 128 of the motor base portion 120, the inner diameter of the inner peripheral surface of the base outer peripheral wall portion 124 of the motor base portion 120 is formed. It is required that b2 is larger than the outer diameter a1 of the hub outer peripheral wall portion 271. Therefore, it is desirable that the outer diameter b1 of the base outer peripheral wall portion 124 is set in consideration of the thickness dimension (for example, about 1 mm) of the base outer peripheral wall portion 124. Here, the thickness dimension of the base outer peripheral wall portion 124 is not limited to the above-mentioned about 1 mm depending on the molding method of the motor base portion 120 or the mechanical strength of the base outer peripheral wall portion 124, for example, a predetermined one. It may be in the numerical range (0.5 to 1.5 mm). Then, it is desirable that the outer diameter b1 of the base outer peripheral wall portion 124 is set in consideration of the above numerical range of the thickness dimension of the base outer peripheral wall portion 124.

The fan device 1 has a first exhaust hole 32 provided in the hub main body 272 and a second exhaust provided in the rotor yoke as exhaust holes penetrating the inside and the outside of the hub 27 in the axis x direction. It has a hole 41. The first exhaust hole 32 and the second exhaust hole 41 allow the air flow F2 introduced from the gap portion G into the substrate accommodating portion 128 of the motor base portion 120 to pass through the motor 20 provided inside the hub 27. It can be discharged to the outside again.

FIG. 6 is an enlarged cross-sectional view schematically showing the configuration of the fan device 100 according to another embodiment of the present invention. As shown in FIG. 6, when the hub outer peripheral wall portion 271 is formed so as to be inclined in a tapered shape or the like, the outer diameter a1 of the hub outer peripheral wall portion 271 of the hub 27 in the fan device 100 is the base outer peripheral wall portion 124. It is defined at the lower end of the hub outer peripheral wall portion 271 which is an opposed portion. Further, when the base outer peripheral wall portion 124 is formed so as to be inclined in a tapered shape or the like, the outer diameter b1 of the base outer peripheral wall portion 124 of the motor base portion 120 is a portion facing the hub outer peripheral wall portion 271. It is defined at the upper end of the wall portion 124.

According to the fan device configured as described above, it is possible to improve the fan efficiency while improving the cooling performance of the components.

In addition, those skilled in the art can appropriately modify the fan device of the present invention according to conventionally known knowledge. As long as the modification still has the structure of the present invention, it is, of course, included in the category of the present invention.

1,100 ... fan device, 10 ... housing, 11 ... first housing, 12 ... second housing, 13 ... stator, 15 ... shaft, 16 ... insulator, 17 ... bearing holder, 18 ... stator core, 19 ... coil, 20 ... Motor, 21 ... Circuit board, 22 ... Bearing, 24 ... Rotor, 25 ... Impeller, 26 ... Magnet, 27 ... Hub, 27a ... Inner peripheral surface, 28 ... Blade, 32 ... First exhaust hole, 33 ... Opening, 35 Bush, 40 ... rotor yoke, 41 ... second exhaust hole, 43 ... insertion hole, 111 ... intake port, 112 ... joint, 113 ... inner circumference, 120 ... motor base, 121 ... base body, 122 ... exhaust Mouth, 123 ... Fixed wing, 124 ... Base outer wall, 124a ... Inner circumference, 125 ... Boss, 126 ... Joint, 127 ... Inner circumference, 128 ... Board housing, 271 ... Hub outer wall, 272 … Hub body

Claims (5)

With a hub
An impeller having a plurality of blades provided on the hub and
The motor that rotates the impeller and
The housing containing the impeller and
With
The housing is formed in a cylindrical shape and has a motor base portion that covers the motor from the lower side in the axial direction.
The motor base portion is a surface extending in the radial direction orthogonal to the axial direction, and covers the motor from the lower side in the axial direction and from the end portion of the base main body portion to the lower side in the axial direction. It has a base outer peripheral wall that extends upward,
The hub is a surface extending in a radial direction orthogonal to the axial direction, and a hub main body portion that covers the motor from the upper side in the axial direction and an end portion of the hub main body portion from the upper side to the lower side in the axial direction. Has an outer peripheral wall of the hub that extends toward
When the diameter of the outer peripheral surface of the hub outer peripheral wall portion is a1 and the diameter of the outer peripheral surface of the base outer peripheral wall portion is b1
1.05 <b1 / a1 <1.13
Is,
Fan device. The diameter of the inner peripheral surface of the base outer peripheral wall portion is larger than the diameter of the outer peripheral surface of the hub outer peripheral wall portion over the entire circumference.
The fan device according to claim 1. The hub body has an exhaust hole penetrating in the axial direction.
The fan device according to claim 1 or 2. A gap is provided between the inner peripheral surface of the motor base portion and the outer peripheral surface of the hub.
The fan device according to any one of claims 1 to 3. The housing has a first housing and a second housing arranged in the axial direction.
The first housing has an intake port that is open on the upper side of the impeller.
The second housing has an exhaust port that is open to the underside of the impeller.
A part of the air flow from the intake port to the exhaust port due to the rotation of the impeller is introduced into the inside of the motor base portion from the gap portion.
The fan device according to claim 4.

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