JP2020133582A - Centrifugal fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve air volume characteristics. A centrifugal fan 1 includes a motor 10 having a shaft 111 and rotating the shaft 111, an impeller 30 mounted on the shaft 111 and rotating together with the shaft 111, and a first case 41 covering one of the impellers 30. , A second case 42 that covers the other side of the impeller 30 by combining with the first case 41, and a space 44 provided in the first case 41 between the first case 41 and the second case 42 are communicated with each other. The suction port 412, the air outlet 45 formed between the first case 41 and the second case 42 and communicating with the space 44, and the air outlet 45 formed in the second case 42 and communicating with the space 44. It is provided with a ventilation hole 424. [Selection diagram] Fig. 1

Description

The present invention relates to a centrifugal fan.

Conventionally, as a centrifugal fan, for example, an impeller is housed between a first case portion and a second case portion having an opening for sucking air, and an outer peripheral portion of the first case portion and an outer peripheral portion of the second case portion are used. It is known that an air outlet for discharging the air blown from the impeller toward the outside of the case is formed between the two (see Patent Documents 1 and 2).

JP-A-2017-223203 Japanese Unexamined Patent Publication No. 2016-031022

By the way, the centrifugal fan is required to increase the air volume characteristic, that is, the air volume (air flow rate). As a measure to increase the air volume in the centrifugal fan, for example, it is conceivable to increase the rotation speed of the impeller, but in this case, the noise from the impeller has increased.

Further, as another measure for increasing the air volume in the centrifugal fan, the outlet formed between the outer peripheral portion of the first case portion and the outer peripheral portion of the second case portion is enlarged, in other words, the outlet It is conceivable to increase the height in the axial direction. However, in order to prevent other members and the like from coming into contact with the impeller, it is desirable that the height of the air outlet in the centrifugal fan in the axial direction is kept low. Further, in the centrifugal fan, the height of the air outlet in the axial direction is increased, so that the configuration of the entire device is increased.

The present invention is an example of the above-mentioned problems, and an object of the present invention is to provide a centrifugal fan capable of improving air volume characteristics.

In order to achieve the above object, the centrifugal fan according to the present invention covers one of a motor having a shaft and rotating the shaft, an impeller mounted on the shaft and rotating together with the shaft, and the impeller. The first case, the second case that covers the other side of the impeller by combining with the first case, and the space provided in the first case between the first case and the second case communicate with each other. The suction port, the air outlet formed between the first case and the second case and communicating with the space, and the ventilation formed in the second case and communicating with the space. With a hole.

In the centrifugal fan according to one aspect of the present invention, a plurality of the ventilation holes are provided along the circumferential direction of the impeller.

In the centrifugal fan according to one aspect of the present invention, the ventilation hole is provided outside the outer peripheral end portion of the impeller.

In the centrifugal fan according to one aspect of the present invention, the second case covers the impeller and the motor from the axial direction of the shaft.

In the centrifugal fan according to one aspect of the present invention, the impeller comprises a hub to be coupled to the shaft, a plurality of blades provided along the circumferential direction of the hub, and a shroud formed in a disk shape. The plurality of blades extend from the shroud in the longitudinal direction of the shaft.

According to the centrifugal fan according to the present invention, it is possible to improve the air volume characteristics.

It is sectional drawing which shows schematic the structure of the centrifugal fan which concerns on embodiment of this invention. It is a front view which shows typically the structure of the 2nd case of the centrifugal fan shown in FIG. It is a front view which shows typically the structure of the 2nd case of the centrifugal fan which concerns on the comparative example of this invention. It is a bottom view which shows schematic structure of the 2nd case of the centrifugal fan which concerns on the modification of this invention.

Hereinafter, the centrifugal fan 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 the configuration of a centrifugal fan 1 according to an embodiment of the present invention. Further, FIG. 2 is a front view schematically showing the configuration of the second case 42 of the centrifugal fan 1.

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 centrifugal fan 1. Further, in the following description, for convenience, the direction in which the centrifugal fan 1 is viewed from the upper side a toward the lower side b is the front surface, and the direction in which the centrifugal fan 1 is viewed from the lower side b toward the upper side a is the bottom surface.

As shown in FIG. 1, the centrifugal fan 1 according to the present embodiment includes a motor 10 having a shaft 111 and rotating the shaft 111, an impeller 30 mounted on the shaft 111 and rotating together with the shaft 111, and an impeller 30. A first case 41 that covers one, a second case 42 that covers the other of the impeller 30 in combination with the first case 41, and a first case 41 and a second case 42 provided in the first case 41. The suction port 412 communicating with the space 44 between them, the air outlet 44 formed between the first case 41 and the second case 42 and communicating with the space 44, and the second case 42 are formed. It is provided with a ventilation hole 424 that communicates with the space 44. Hereinafter, the configuration and operation of the centrifugal fan 1 will be specifically described.

[Centrifugal fan configuration]
The centrifugal fan 1 includes a casing 40 composed of both a first case 41 and a second case 42 made of resin. In the centrifugal fan 1, the motor 10 and the impeller 30 are housed inside the casing 40.

The motor 10 is an outer rotor type brushless DC (Direct Current) motor. The motor 10 includes a shaft 111, a bearing holder 112, a bearing 113, a stator 114, a rotor magnet 115, and a rotor yoke 116.

The shaft 111 is a rod-shaped member arranged with the axis x direction as the longitudinal direction. The bearing holder 112 is a hollow cylindrical member provided on the outer peripheral side c of the shaft 111. The bearing holder 112 is made of metal, for example. The bearing holder 112 is fixed to the center of the concave bearing holding portion 423 formed in the second case 42. The bearing 113 is mounted inside the bearing holder 112. As the bearing 113, an appropriate type such as a ball bearing can be used. For example, two bearings 113 are provided in the bearing holder 112, and the shaft 111 is supported by the pair of bearings 113.

The stator 114 is fitted to the outer peripheral side c of the bearing holder 112 fixed to the second case 42. The stator 114 includes, for example, a stator core formed by laminating a plurality of electromagnetic steel plates, an insulator provided on the stator core, and a coil wound on the stator core via the insulator. The rotor magnet 115 is attached to, for example, the inner peripheral surface of the rotor yoke 116 attached to the impeller 30.

The impeller 30 is housed inside the casing 40 as described above. The impeller 30 is made of resin, for example, and includes a main plate 31, a shroud 32, a plurality of blades 33, a motor accommodating portion 34, a hub 35, a shaft hole 36, an edge portion 37, a flow path 38, and an impeller outlet 39. ..

The main plate 31 is formed in a shape suitable for the impeller 30 to rotate, for example, in a disk shape when viewed from a direction along the axis x. As shown in FIG. 1, the main plate 31 has, for example, a plate-like outer peripheral side c when viewed from the side surface direction of the impeller 30. Further, the main plate 31 is configured such that the portion on the inner peripheral side d is convex to the upper side a, for example.

The portion of the main plate 31 having a convex shape on the upper side a is a motor accommodating portion 34 for accommodating the components of the motor 10. A hub 35 and a shaft hole 36 are provided at the rotation center position of the impeller 30 in the motor accommodating portion 34 in order to rotatably support the impeller 30 with respect to the shaft 111. The front view shape and the side view shape of the main plate 31 are not limited to the above examples as long as they are suitable for the rotational movement of the impeller 30. The front view shape of the main plate 31 may be, for example, a substantially disk shape in which a part of the disk shape is deformed and notches and protrusions are provided. Further, the side view shape of the main plate 31 may be, for example, a substantially plate shape in which a part of the plate shape is deformed to provide unevenness.

The shroud 32 is attached so as to cover the main plate 31 from the upper side a. The shroud 32 has a shape that covers almost the entire surface of the main plate 31, and is formed in a disk shape or a substantially disk shape in a front view, for example. The shroud 32 has a front surface shown in FIG. 1 and a bottom surface which is a surface opposite to the front surface. The bottom surface of the shroud 32 faces the front surface of the main plate 31. An opening 321 is provided in the central portion of the shroud 32.

The opening 321 is a hole that penetrates the front surface and the bottom surface of the shroud 32. The opening 321 serves as an air intake port (suction port) for the inside of the impeller 30 surrounded by the main plate 31, the shroud 32, and the plurality of blades 33 when the impeller 30 rotates.

A plurality of blades 33 are arranged between the main plate 31 and the shroud 32. The blades 33 are, for example, rearward blades having the same shape. That is, the shape of the blade 33 in front view is inclined backward with respect to a predetermined direction, for example, the direction in which the shaft 111 rotates. In detail, the front view shape of the blade 33 is curved in the direction opposite to the direction in which the shaft 111 rotates. The blades 33 are evenly arranged in the circumferential direction between the main plate 31 and the shroud 32. Further, the blade 33 extends from the shroud 32 in the longitudinal direction (upper a direction) of the shaft 111. The spacing and shape of the arrangement of the plurality of blades 33 in the circumferential direction is not limited to the above example.

The flow path 38 is a region formed between the main plate 31 and the shroud 32 by superimposing the main plate 31 and the shroud 32. A blade 33 is arranged in the flow path 38. The flow path 38 communicates with the opening 321 of the shroud 32 and the impeller outlet 39 provided at the edge 37 on the outer peripheral side c of the impeller 30.

As described above, the casing 40 is composed of the first case 41, the second case 42, the space 44, and the air outlet 45. In the first case 41, the impeller 30 is covered from the upper side a. The second case 42 covers the impeller 30 from the lower side b.

The first case 41 has a shape that covers almost the entire surface of the impeller 30 in order to cover the impeller 30, and is formed in a disk shape or a substantially disk shape in a front view, for example. The first case 41 is a plurality of columns provided between the first case main body 411 that defines the approximate shape of the first case 41, the suction port 412 that communicates the inside and the outside of the casing 40, and the second case 42. It is provided with 413. In the first case 41, the first case main body 411, the suction port 412, and the support column 413 are integrally molded by, for example, injection molding of resin.

The second case 42 covers the impeller 30 and the motor 10 from the axial direction of the shaft 111. The second case 42 has a shape that covers almost the entire surface of the impeller 30, and is formed in a disk shape or a substantially disk shape in a front view, for example. The second case 42 includes a circuit board accommodating portion 422, a bearing holding portion 423, and a ventilation hole 424 in the second case main body 421 that defines the approximate shape of the second case 42. In the second case 42, the second case main body 421, the circuit board accommodating portion 422, the bearing holding portion 423, and the ventilation hole 424 are integrally molded by, for example, injection molding of resin.

The circuit board accommodating portion 422 covers the motor 10 and the impeller 30 from the lower side b, and accommodates the circuit board 60 or the like on which the electronic component 70 is mounted. The bearing holding portion 423 is a concave portion provided in the central portion of the second case main body 421 and holding the bearing holder 112.

The ventilation hole 424 is a hole that communicates the inside of the second case body 421 facing the first case 41 and the outside on the opposite side thereof. As shown in FIG. 2, a plurality of ventilation holes 424 are provided at equal intervals, for example, 10 along the circumferential direction of the impeller 30. Further, the ventilation hole 424 is provided on the outer side c from the outer peripheral end portion of the impeller 30. The ventilation holes 424 are all formed, for example, in the same shape (circular shape, diameter 3 mm). The ventilation hole 424 is preferably formed at a position symmetrical with respect to the axis x, which is the center of rotation of the impeller 30.

The casing 40 is formed by connecting a first case 41 that covers the impeller 30 from the upper side a and a second case 42 that covers the impeller 30 from the lower side b. Specifically, the first case 41 and the second case 42 are combined as follows, for example. First, a boss, which is a pin-shaped protrusion, is formed at the tip of the support column 413 provided in the first case 41. The boss is inserted into a through hole 425 (see FIG. 2) formed in the second case 42. After inserting the boss, the tip of the boss protruding from the through hole 425 is thermally deformed by a method such as thermal caulking or infrared caulking. As the boss is crushed by this thermal deformation, a tip portion 43 having a diameter larger than that of the through hole 425 is formed as shown in FIG. By doing so, the casing 40 is connected to the first case 41 and the second case 42 via the support column 413. In the casing 40, a space 44 having a predetermined height is formed between the first case 41 and the second case 42 by the columns 413. Further, in the region extending outside the diameter of the space 44 and formed over the entire circumference, an air outlet 45 that connects the space 44 and the outside of the centrifugal fan 1 is formed. ..

The connection between the first case 41 and the second case 42 may be configured by a fastening member such as a screw or a bolt instead of the method of thermally deforming the boss as described above. Further, the support column 413 is not limited to the one provided in the first case main body 411 as described above. That is, the support column may be integrally molded together with the second case main body 421 by injection molding of resin.

In the second case 42, a connector 50 for electrically connecting the circuit board 60 of the centrifugal fan 1 and the like, such as a connector of an external power supply (not shown), is provided on the lower side b of the circuit board accommodating portion 422. The connector 50 is composed of a connector housing 51, a connector accommodating portion 52, and a connector pin 53. The connector housing 51 is integrally molded with the second case main body 421 of the second case 42 with resin. The connector accommodating portion 52 can accommodate a mating connector (not shown) formed inside the connector housing 51. The connector pin 53 is a terminal of a conductive member that is integrally molded with the second case main body 421 inside the connector accommodating portion 52 by insert molding. One end of the connector pin 53 exposed in the connector housing 52 is electrically connected to the connector pin of the mating connector housed in the connector housing 52. The other end of the connector pin 53 is electrically connected to a wiring pattern (not shown) of the circuit board 60. An electronic circuit and an electronic component 70 necessary for driving a motor are mounted on the circuit board 60.

The connector 50 is formed by insert-molding the connector pin 53 into the second case main body 421 and integrally molding the connector housing 51, but instead of this, a lead wire may be connected.

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

The motor 10 rotates the shaft 111 by flowing a drive current. The shaft 111 of the motor 10 is rotatably supported by a pair of bearings 113 mounted on the bearing holder 112, and is coupled to a shaft hole 36 provided in the hub 35 of the impeller 30. Therefore, when the motor 10 is driven, the shaft 111 rotates about the axis x, and the impeller 30 also rotates about the axis x accordingly.

As the impeller 30 rotates, the air outside the centrifugal fan 1 is sucked into the space 44 inside the casing 40 from the suction port 412 provided in the center of the first case 41. The air sucked into the space 44 of the casing 40 is sucked into the flow path 38 inside the impeller 30 through the opening 321 provided in the shroud 32. The air sucked into the flow path 38 of the impeller 30 passes between the openings 321 and the blades 33 and is blown out to the impeller outlet 39 provided at the edge 37 on the outer peripheral side c of the impeller 30. The air blown from the impeller outlet 39 of the impeller 30 into the space 44 inside the casing 40 is blown out of the casing 40 from the outlet 45 which is the outlet of the space 44 in the casing 40.

Here, in the second case 42 that covers the lower side b of the impeller 30 in the casing 40, the centrifugal fan 1 communicates the inside of the second case body 421 facing the first case 41 and the outside on the opposite side thereof. It is equipped with a ventilation hole 424. A part of the air blown out from the impeller outlet 39 passes through the ventilation hole 424 and is sent out to the outside.

The position where the ventilation hole 424 is provided is preferably in the vicinity of the support column 413. In the vicinity of the support column 413, the air flow blown out from the outlet of the impeller 30 collides with each other, so that the flow velocity in the vicinity of the support column 413 is biased. In this way, by providing the ventilation holes 424 in the vicinity of the support columns 413, it is possible to suppress the deviation of the flow velocity of the wind sent from the centrifugal fan 1.

Next, the presence / absence of the ventilation holes 424 and the change in the air volume characteristics depending on the number of the ventilation holes 424 in the centrifugal fan 1 will be described with reference to comparative examples and modification examples.

FIG. 3 is a front view schematically showing the configuration of the second case 42 of the centrifugal fan 100 according to the comparative example of the present invention. As shown in FIG. 3, the centrifugal fan 100 according to the comparative example is different from the centrifugal fan 1 only in that the ventilation hole 424 is not provided in the second case main body 421 of the second case 420.

FIG. 4 is a bottom view schematically showing the configuration of the centrifugal fan 1B according to the modified example of the present invention. As shown in FIG. 4, the centrifugal fan 1B according to the modified example differs from the centrifugal fan 1 in that the number of ventilation holes 424B provided in the second case main body 421 of the second case 42B is 22. ..

Table 1 shows the centrifugal fan 100 of the comparative example in which the second case 42 is not provided with ventilation holes when the static pressure is 600 Pa, and the number of ventilation holes is 4, 6, 8, and 10 (centrifugal). The difference in the flow rate (m ³ / h) between the centrifugal fan provided with 12 (corresponding to fan 1), 12 and 22 (corresponding to centrifugal fan 1B) is shown.

According to Table 1, the centrifugal fan 1 provided with the ventilation hole 424 in the second case 42 has a flow rate of the air to be sent out as compared with the centrifugal fan 100 having no ventilation hole in the second case 42. Can be increased. Further, according to Table 1, it can be seen that it is desirable that the number of ventilation holes 424 in the centrifugal fan 1 is about 4 to 10 as compared with the centrifugal fan 1B of the modified example.

In the centrifugal fan 1 configured as described above, the second case 42 located on the main plate 31 side of the impeller 30 in the casing 40 is provided with a ventilation hole 424 that communicates the inside and the outside of the casing 40. There is. With this configuration, according to the centrifugal fan 1, the air volume to be sent can be increased. In particular, according to the centrifugal fan 1, unlike the case where the rotation speed of the impeller is increased, the air volume can be increased without increasing the noise from the impeller. Further, according to the centrifugal fan 1, unlike the case where the air outlet is enlarged, the configuration of the entire device can be miniaturized, and the air volume can be increased while preventing other members and the like from coming into contact with the impeller.

Therefore, according to the centrifugal fan 1 in which the ventilation hole 424 is provided in the second case 42 of the casing 40, the air volume of the fan as a whole can be increased, so that the air volume characteristics can be improved.

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

1 ... Centrifugal fan, 10 ... Motor, 30 ... Impeller, 31 ... Main plate, 32 ... Shroud, 33 ... Blade, 34 ... Motor housing, 35 ... Hub, 36 ... Shaft hole, 37 ... Edge, 38 ... Flow path, 39 ... impeller outlet, 40 ... casing, 41 ... first case, 42 ... second case, 43 ... tip, 44 ... space, 45 ... outlet, 50 ... connector, 51 ... connector housing, 52 ... connector housing , 53 ... connector pin, 60 ... circuit board, 70 ... electronic component, 111 ... shaft, 112 ... bearing holder, 113 ... bearing, 114 ... stator, 115 ... rotor magnet, 116 ... rotor yoke, 321 ... opening, 411 ... 1 case body, 412 ... suction port, 413 ... support, 421 ... second case body, 422 ... circuit board housing part, 423 ... bearing holding part, 424 ... ventilation hole, 425 ... through hole

Claims (5)

A motor that has a shaft and rotates the shaft,
An impeller mounted on the shaft and rotating with the shaft,
The first case that covers one of the impellers,
A second case that covers the other side of the impeller by combining with the first case,
A suction port provided in the first case and communicating with the space between the first case and the second case,
An air outlet formed between the first case and the second case and communicating with the space,
A ventilation hole formed in the second case and communicating with the space,
Equipped with a centrifugal fan. A plurality of the ventilation holes are provided along the circumferential direction of the impeller.
The centrifugal fan according to claim 1. The ventilation hole is provided outside the outer peripheral end of the impeller.
The centrifugal fan according to claim 2. The second case covers the impeller and the motor from the axial direction of the shaft.
The centrifugal fan according to any one of claims 1 to 3. The impeller has a hub to be coupled to the shaft, a plurality of blades provided along the circumferential direction of the hub, and a shroud formed in a disk shape.
The plurality of blades extend from the shroud in the longitudinal direction of the shaft.
The centrifugal fan according to any one of claims 1 to 4.

Images