CN110886709B

CN110886709B - Blower and blower device using the same

Info

Publication number: CN110886709B
Application number: CN201910851615.8A
Authority: CN
Inventors: 刘俊贤; 李柏毅
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2018-09-11
Filing date: 2019-09-10
Publication date: 2021-07-09
Anticipated expiration: 2039-09-10
Also published as: JP7119802B2; CN211202347U; CN110886709A; JP2020041480A

Abstract

The invention provides a blower and a blower device using the blower, wherein the casing of the blower is provided with: a first intake port located on one axial side of the first impeller; a second air inlet located on the other axial side of the second impeller; a blower port located radially outward of the first impeller and the second impeller; a first wind tunnel communicated with the first air intake and the air supply port; the second wind tunnel is communicated with the second air suction port and the air supply port; and a wall portion axially separating the first and second air tunnels. The first air tunnel and the second air tunnel have a first opening and a second opening, respectively, at positions on the most upstream side in the direction of air flow in the circumferential direction. The thickness of the wall portion in the axial direction becomes thinner from the start end of the wall portion located on the upstream side in the direction of air flow in the circumferential direction toward the end of the wall portion located on the downstream side.

Description

Blower and blower device using the same

Technical Field

The present invention relates to a blower and a blower device using the same.

Background

Conventionally, a centrifugal blower having two impellers has been proposed. For example, in the blower disclosed in patent document 1, a first impeller and a second impeller are connected to both ends of a rotating shaft of a motor, respectively. When the first impeller and the second impeller are rotated, air is sucked into the case from both ends in the axial direction. The air travels circumferentially within the tank.

An air tunnel (hereinafter also referred to as a first air tunnel) that forms a flow path of air that travels inside the casing as the first impeller rotates is provided inside the casing. Further, an air tunnel (hereinafter also referred to as a second air tunnel) that forms a flow path of air that travels inside the device by the rotation of the second impeller is provided inside the casing. The first wind tunnel and the second wind tunnel are completely separated from each other, and the respective air flows in the first wind tunnel and the second wind tunnel and is discharged from the respective air supply ports.

Patent document 1: international laid-open publication No. 2016-170881

In a centrifugal blower having a first wind tunnel and a second wind tunnel, as a method for increasing the blowing air volume, for example, there are the following methods: the first and second wind tunnels are shielded from the upstream end in the direction of air flow in the circumferential direction. It is considered that the amount of blown air can be increased by shielding the end portion and efficiently guiding the sucked air to the air blowing port. However, when the end portion is shielded, a large negative pressure is generated between the end portion and the impeller, and a buzzing sound (noise) is generated due to the negative pressure. Therefore, from the viewpoint of reducing the generation of noise, it is preferable to open the end portion.

However, when the end portion is opened, since the opening portion is formed in the end portion, the upstream side of the first air channel is spatially connected to the downstream side of the first air channel via the opening portion, outside the first air channel. In this case, there is a possibility that air flowing from the upstream side toward the downstream side in the circumferential direction inside the first air tunnel may again detour back into the first air tunnel via the opening portion. When such a wraparound occurs, the amount of air from the downstream side of the first wind tunnel toward the air blowing port decreases, and the amount of air discharged from the air blowing port (the amount of blowing air) decreases. In addition, when the end portion of the second air tunnel is opened, the amount of the blown air may be reduced for the same reason as described above.

Disclosure of Invention

In view of the above circumstances, an object of the present invention is to provide the following air blower and air blowing device using the same: in the structure in which air sucked in from the axial direction by the two impellers is caused to travel in the circumferential direction inside the first and second wind tunnels and is discharged from the air blowing port, it is possible to reduce noise generation at the end portions on the circumferential upstream side of the first and second wind tunnels and increase the amount of blowing air.

An exemplary blower of the present invention includes: a motor having a shaft rotating about a central axis; a first impeller and a second impeller respectively connected to both axial ends of the shaft; and a housing that houses the motor, the first impeller, and the second impeller therein, the housing having: a first intake port located on one axial side of the first impeller; a second air inlet port located on the other axial side of the second impeller; a supply port located radially outward of the shaft relative to the first impeller and the second impeller; a first wind tunnel that communicates with the first intake port, extends in the circumferential direction of the shaft, and communicates with the air supply port on the most downstream side in the direction of air flow in the circumferential direction of the first wind tunnel; a second air tunnel that communicates with the second air intake port, extends in the circumferential direction of the shaft, and communicates with the air supply port on the most downstream side in the direction of air flow in the circumferential direction of the second air tunnel; and a wall portion extending in the circumferential direction and partitioning the first air tunnel and the second air tunnel in the axial direction, wherein the first air tunnel and the second air tunnel have a first opening portion and a second opening portion at positions on an upstream side in a direction of air flow in the circumferential direction, respectively, and a thickness of the wall portion in the axial direction is reduced from a start end of the wall portion located on the upstream side in the direction of air flow in the circumferential direction toward a terminal end of the wall portion located on the downstream side.

The thickness of the wall portion that separates the first air tunnel and the second air tunnel in the axial direction becomes thinner from the start end toward the end in the circumferential direction. Accordingly, even when the first opening and the second opening are provided at the positions on the most upstream side in the circumferential direction of the first air tunnel and the second air tunnel, respectively, to reduce the noise and the noise caused by the negative pressure, it is possible to reduce the possibility that the respective air flowing in the circumferential direction inside the first air tunnel and the second air tunnel is detoured to the first air tunnel and the second air tunnel via the first opening and the second opening. Therefore, it is possible to reduce the noise caused by the negative pressure generated at the upstream side end portions of the first and second wind tunnels, and to efficiently guide the respective air from the downstream sides of the first and second wind tunnels to the air blowing ports, thereby increasing the air blowing amount.

Drawings

Fig. 1 is a perspective view of a blower according to an embodiment of the present invention.

Fig. 2 is a side view of the blower.

Fig. 3 is a perspective view of the blower viewed from a different angle than fig. 1.

Fig. 4 is a front view of the blower.

Fig. 5 is an exploded perspective view of the blower.

Fig. 6 is a longitudinal sectional view obtained by cutting the blower in the axial direction along line a-a of fig. 3.

Fig. 7 is a longitudinal sectional view obtained by cutting the blower in the axial direction along line B-B of fig. 3.

Fig. 8 is a perspective view of the blower in a state where the first upper case is omitted from illustration.

Fig. 9 is a perspective view of the blower in a state in which the first upper case, the first lower case, and the second upper case are not shown.

Fig. 10 is a plan view of the blower in a state where the first upper case is not shown.

Fig. 11 is a perspective view of the blower.

Fig. 12 is a perspective view of the blower device in a state in which the casing and the blower therein are not shown.

Fig. 13 is an exploded perspective view of the blower in a state where the casing is not shown.

Fig. 14 is a partial perspective view of the air blowing device during air blowing.

Fig. 15 is a side view of the blower device when the inside of the casing is viewed from the second intake port side in a state before the blower rotates.

Fig. 16 is a side view of the blower device when the inside of the casing is viewed from the second intake port side in a state where the blower is rotated.

Description of the reference symbols

1: a blower; 2: a motor; 2 a: a shaft; 3: a first impeller; 4: a second impeller; 5: a housing; 6: a first impeller housing; 7: a second impeller housing; 8: a snap-fit portion; 32: a first blade section; 42: a second blade portion; 51: a first air intake port; 52: a second air suction port; 53: an air supply outlet; 53 a: a first divided air supply outlet; 53 b: a second divided air supply outlet; 54: a first wind tunnel; 54 a: a first upper wind tunnel; 54 b: a first lower wind tunnel; 55: a second wind tunnel; 55 a: a second upper wind tunnel; 55 b: a second lower wind tunnel; 56: a wall portion; 56 a: a first dividing wall portion; 56 b: a second partition wall portion; 56U: a starting end; 56D: a terminal; 57: a first opening portion; 58: a second opening portion; 59: a rim portion; 59 a: an inner surface; 61: a first upper case; 62: a first lower case; 71: a second upper case; 72: a second lower case; 100: an air supply device; 200: a box body; 300: a filter; 400: a rotating mechanism; 401: a main body-side gear; 402: a drive gear; 403: a support roller; c: a central axis; l: and (4) a plane.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification, an axis line which is a rotation center of a shaft of the motor is referred to as a "central axis line", and a direction in which the central axis line extends is simply referred to as an "axial direction". In addition, a direction perpendicular to the central axis from the central axis is simply referred to as a "radial direction", and a direction along an arc drawn with the central axis as a center is simply referred to as a "circumferential direction".

In the present specification, for convenience of explanation, the axial direction is taken as the vertical direction, and the vertical direction of the blower is made to correspond to the vertical direction of the axial direction, and the shape and positional relationship of the respective portions will be described. In this case, one axial direction is referred to as "up" and the other axial direction is referred to as "down". One axial side is referred to as "upper side", and the other axial side is referred to as "lower side". According to this definition, for example, the "upper side" in the axial direction is the "first intake port side" and the "lower side" is the "second intake port side" of the blower. The vertical direction is not limited to the orientation and positional relationship when the blower and the blower are used.

In the present specification, a cross section parallel to the axial direction is referred to as a "longitudinal cross section". The term "parallel" used in the present specification does not mean parallel in a strict sense, and includes substantially parallel.

< 1. blower >

(1-1. schematic construction of blower)

Fig. 1 is a perspective view of a blower 1 according to an exemplary embodiment of the present invention, and fig. 2 is a side view of the blower 1. Fig. 3 is a perspective view of the blower 1 viewed from a different angle from fig. 1, and fig. 4 is a front view of the blower 1. Fig. 5 is an exploded perspective view of the blower 1. Here, the direction of the blower 1 when viewed in the direction opposite to the direction in which air is discharged from the air outlet 53 of the blower 1 is referred to as "front". The blower 1 is a centrifugal blower having a motor 2, a first impeller 3 and a second impeller 4, and a casing 5.

The motor 2 has a shaft 2a that rotates about a central axis C. The shaft 2a is a columnar member made of metal such as stainless steel, and extends upward and downward along the shaft. The motor 2 includes a shaft 2a, a bearing, a stator, and a rotor. The bearing supports the shaft 2a rotatably about the center axis C. The stator and the rotor rotate the shaft 2a in accordance with a change in magnetic flux based on the supply of the drive current. The motor 2 may be a general motor, and is not particularly limited.

The first impeller 3 is connected to an end portion of the shaft 2a on one axial side (upper side). The second impeller 4 is connected to the other axial end (lower side) of the shaft 2 a. The first impeller 3 and the second impeller 4 rotate in the same direction in the circumferential direction as the shaft 2a rotates around the central axis C. The casing 5 is a housing that accommodates the motor 2, the first impeller 3, and the second impeller 4 therein, and is made of, for example, resin.

That is, the blower 1 includes: a motor 2 having a shaft 2a that rotates about a central axis C; a first impeller 3 and a second impeller 4 connected to one axial end and the other axial end of the shaft 2a, respectively; and a casing 5 that houses the first impeller 3 and the second impeller 4 therein.

The casing 5 has a first air intake port 51, a second air intake port 52, an air supply port 53, a first air tunnel 54, a second air tunnel 55, and a wall portion 56. The first air inlet 51 and the second air inlet 52 are opening portions for taking in external air into the casing 5. In the casing 5, the first intake port 51 is located axially above the first impeller 3, and the second intake port 52 is located axially below the second impeller 4.

The air blowing port 53 is an opening portion for discharging air taken into the casing 5 through the first air inlet 51 and the second air inlet 52 to the outside. The air blowing port 53 is formed at a predetermined position on the outer circumferential surface 5a on the radially outermost side of the casing 5. Therefore, in the casing 5, the air outlet 53 is positioned radially outward of the first impeller 3 and the second impeller 4 with respect to the shaft 2 a. The number of the air blowing ports 53, that is, the number of openings forming the air blowing ports 53 is one.

The first air tunnel 54 is an air tunnel forming an air flow path for guiding air sucked from the first air intake port 51 to the air blowing port 53. The first air tunnel 54 communicates with the first intake port 51 and extends in the circumferential direction of the shaft 2 a. The most downstream side in the direction of air flow in the circumferential direction of the first air tunnel 54 communicates with the air blowing port 53.

The second air tunnel 55 is an air tunnel forming an air flow path for guiding air taken in from the second air inlet 52 to the air blowing port 53. The second air channel 55 communicates with the second air inlet 52 and extends in the circumferential direction of the shaft 2 a. The most downstream side in the direction of air flow in the circumferential direction of the second air tunnel 55 communicates with the air blowing port 53. The first air tunnel 54 and the second air tunnel 55 have a first opening 57 and a second opening 58, respectively, at positions on the most upstream side in the direction of air flow in the circumferential direction.

A space S is present between the first opening 57 and the air outlet 53 and between the second opening 58 and the air outlet 53 in the axial direction. Therefore, the first opening 57 and the second opening 58 are opened to face the space S, and the air blowing port 53 is also opened to face the space S. The first opening 57 and the second opening 58 are located radially outward (outer circumferential side) of the first impeller 3 and the second impeller 4, respectively, and are arranged so as to be separated in the axial direction. Further, the downstream side of the first air tunnel 54 and the downstream side of the second air tunnel 55 are connected to the air blowing port 53 via the space S. Therefore, the downstream side of the first air tunnel 54 and the downstream side of the second air tunnel 55 are also open facing the space S.

The wall portion 56 is a wall that axially partitions the first air tunnel 54 and the second air tunnel 55. In other words, the wall portion 56 is a wall for axially separating the first air tunnel 54 and the second air tunnel 55. The wall portion 56 is formed to extend in the circumferential direction of the shaft 2 a. The thickness of the wall portion 56 in the axial direction changes in the circumferential direction, but this point will be described later. In the present embodiment, the upstream side position in the circumferential direction of the wall portion 56 in the air flow direction is referred to as a start end 56U, and the downstream side position is referred to as a terminal end 56D.

That is, the housing 5 has: a first intake port 51 located on one axial side of the first impeller 3; a second inlet port 52 located on the other axial side of the second impeller 4; one air supply opening 53 located radially outward of the first impeller 3 and the second impeller 4 with respect to the shaft 2 a; a first air tunnel 54 which communicates with the first air intake port 51 and extends in the circumferential direction of the shaft 2a, and the most downstream side in the direction of air flow in the circumferential direction of the first air tunnel 54 communicates with the air blowing port 53; a second air tunnel 55 which communicates with the second air inlet 52 and extends in the circumferential direction of the shaft 2a, and the most downstream side in the direction of air flow in the circumferential direction of the second air tunnel 55 communicates with the air blowing port 53; and a wall portion 56 extending in the circumferential direction and axially partitioning the first air channel 54 and the second air channel 55. The first air tunnel 54 and the second air tunnel 55 have a first opening 57 and a second opening 58, respectively, at positions on the most upstream side in the direction of air flow in the circumferential direction.

(1-2. about the impeller casing constituting the outer casing)

Next, details of the housing 5 will be described with reference to fig. 6 and 7 in addition to fig. 1 to 5. Fig. 6 is a longitudinal sectional view obtained by cutting the blower 1 in the axial direction along the line a-a of fig. 3. Fig. 7 is a vertical cross-sectional view of the blower 1 cut along the axial direction along the line B-B in fig. 3. Fig. 7 is also a longitudinal sectional view of the terminal end 56D passing through the wall portion 56. In fig. 6 and 7, the interior of the motor 2 is not illustrated, but for convenience, only the outer shape of the motor 2 is shown by a solid line. The motor 2 may be configured by separately disposing components such as a stator and a rotor inside the housing 5.

The casing 5 has a first impeller shell 6 and a second impeller shell 7. The first impeller housing 6 houses the first impeller 3, and the second impeller housing 7 houses the second impeller 4. Therefore, the first impeller housing 6 is located on one side (upper side) in the axial direction, and the second impeller housing 7 is located on the other side (lower side) in the axial direction. The first impeller 3 and the first impeller housing 6 and the second impeller 4 and the second impeller housing 7 are symmetrical with respect to a plane L that is perpendicular to the center axis C and passes through the center in the axial direction of the wall portion 56.

The first impeller housing 6 has a first divided wall portion 56a and a first divided air blowing port 53a in addition to the first air intake port 51 and the first air tunnel 54 described above. The first dividing wall 56a is one of two parts that divide the wall 56 into two parts in the vertical direction by a plane perpendicular to the axial direction. That is, the first divided wall portion 56a is the upper half portion of the wall portion 56. The first divided air blowing port 53a is one of two divided air blowing ports 53 in the vertical direction by a plane perpendicular to the axial direction. That is, the first divided blowing port 53a is the upper half of the blowing port 53.

The second impeller casing 7 includes a second partition wall 56b and a second partition outlet 53b in addition to the second inlet 52 and the second air channel 55. The second divided wall 56b is a wall 56 divided into two parts by a surface perpendicular to the axial direction. That is, the second partition wall 56b is a lower half of the wall 56. The second split outlet 53b is the other of the two parts of the outlet 53. That is, the second split air blowing port 53b is the lower half of the air blowing port 53.

That is, the casing 5 has a first impeller casing 6 that houses the first impeller 3 and a second impeller casing 7 that houses the second impeller 4. The first impeller housing 6 has a first air intake port 51, a first air tunnel 54, a first divided wall portion 56a that divides the wall portion 56 into two parts, and a first divided air outlet 53a that divides the air outlet 53 into two parts, the first divided wall portion 56a being one part of the wall portion 56 into two parts. The second impeller casing 7 has a second air inlet 52, a second air tunnel 55, a second divided wall 56b and a second divided air outlet 53b, the second divided wall 56b being the other of the two divided walls 56, and the second divided air outlet 53b being the other of the two divided air outlets 53. With this structure, the first impeller shell 6 and the second impeller shell 7 can be separately molded and connected in the axial direction, thereby easily realizing the outer shell 5.

In addition, the first impeller housing 6 has a first upper housing 61 and a first lower housing 62. The first upper case 61 has a first air intake port 51. The first lower case 62 is located on the other side (lower side) in the axial direction than the first upper case 61, and is axially connected to the first upper case 61.

The second impeller housing 7 has a second upper housing 71 and a second lower housing 72. The second lower case 72 has the second suction port 52. The second upper housing 71 is located between the first lower housing 62 and the second lower housing 72, and is axially connected to the first lower housing 62 and the second lower housing 72.

Further, a first divided wall portion 56a constituting a part of the wall portion 56 is positioned in the first lower case 62, and a second divided wall portion 56b constituting the other part of the wall portion 56 is positioned in the second upper case 71. Thus, the wall portion 56 is located at the first lower case 62 and the second upper case 71.

That is, when one axial side is set to be up and the other axial side is set to be down, the first impeller housing 6 includes: a first upper case 61 having a first air intake 51; and a first lower case 62 axially connected to the first upper case 61. The second impeller casing 7 has: a second lower case 72 having a second suction port 52; and a second upper housing 71 axially connected with the first lower housing 62 and the second lower housing 72. The wall 56 is located in the first lower case 62 and the second upper case 71.

According to this configuration, the first upper casing 61, the first lower casing 62, the second upper casing 71, and the second lower casing 72 are connected in the axial direction, whereby the casing 5 including the first impeller casing 6, the second impeller casing 7, and the wall portion 56 can be easily configured, and the assembling property of the casing 5 can be improved. Further, a space for disposing the motor 2 can be easily formed between the first lower case 62 and the second upper case 71, and the assembling property of the blower 1 can be improved.

In addition, the first upper case 61 has a first upper air tunnel 54 a. The first lower housing 62 has a first lower air tunnel 54 b. The first upper air tunnel 54a is an air tunnel forming an air flow path communicating with the first intake port 51. The first lower air tunnel 54b is an air tunnel forming an air flow path communicating with the first upper air tunnel 54 a. The first air tunnel 54 is formed by axially combining the first upper air tunnel 54a and the first lower air tunnel 54 b.

The second upper housing 71 has a second upper air tunnel 55 a. The second lower housing 72 has a second lower air tunnel 55 b. The second upper air tunnel 55a is an air tunnel forming an air flow path communicating with the second air inlet 52. The second lower air tunnel 55b is an air tunnel forming an air flow path communicating with the second upper air tunnel 55 a. The second air tunnel 55 is formed by axially combining the second upper air tunnel 55a and the second lower air tunnel 55 b. The first lower air hole 54b of the first lower housing 62 and the second upper air hole 55a of the second upper housing 71 are axially separated by the wall portion 56.

That is, the first air tunnel 54 includes a first upper air tunnel 54a communicating with the first intake port 51 and a first lower air tunnel 54b communicating with the first upper air tunnel 54 a. The second air tunnel 55 has a second lower air tunnel 55b communicating with the second suction port 52 and a second upper air tunnel 55a communicating with the second lower air tunnel 55 b. The first upper case 61 has a first upper air tunnel 54 a. The first lower housing 62 has a first lower air tunnel 54 b. The second upper housing 71 has a second upper air tunnel 55 a. The second lower housing 72 has a second lower air tunnel 55 b. The wall portion 56 axially separates the first lower air tunnel 54b of the first lower housing 62 from the second upper air tunnel 55a of the second upper housing 71.

According to this configuration, the first upper casing 61 and the first lower casing 62 are axially connected to each other, whereby the first impeller casing 6 having the first air hole 54 obtained by combining the first upper air hole 54a and the first lower air hole 54b can be realized. Further, by connecting the second upper casing 71 and the second lower casing 72 in the axial direction, the second impeller casing 7 having the second air hole 55 obtained by combining the second upper air hole 55a and the second lower air hole 55b can be realized. Then, by connecting the first lower case 62 and the second upper case 71 in the axial direction, the housing 5 can be realized in which the first lower air hole 54b and the second upper air hole 55a are axially separated by the wall portion 56.

(1-3. connection in the axial direction of the respective cases constituting the outer case)

As shown in fig. 1 to 5, the first lower case 62 has a convex portion 81. The convex portion 81 is a projection on the outer peripheral surface 62a located on the radially outer side of the first lower case 62. The upper surface of the convex portion 81 on the outer peripheral surface 62a is inclined downward on the outer peripheral side. On the other hand, the first upper case 61 has a hook portion 82. The hook portion 82 has elasticity and is located on the outer peripheral surface 61a on the radially outer side of the first upper case 61. The hook portion 82 has a curved shape that protrudes from a position on the outer peripheral surface 61a toward the first lower case 62 side and is bent along the outer shape of the convex portion 81. The outer peripheral surface 61a of the first upper case 61 and the outer peripheral surface 62a of the first lower case 62 are included in the outer peripheral surface 5a of the housing 5.

When the first upper case 61 is brought closer to the first lower case 62 side from the axial upper side, the convex portion 81 of the first lower case 62 pushes up the hook portion 82 of the first upper case 61, and the hook portion 82 is slightly elastically deformed. Then, immediately after the axial lower end of the hook portion 82 passes the projection 81, the lifting of the hook portion 82 by the projection 81 is released, and therefore the hook portion 82 is restored to the state before elastic deformation by the restoring force and is hooked to the projection 81. Thus, the first upper case 61 is fixed to the first lower case 62, and the first upper case 61 does not fall off upward in the axial direction with respect to the first lower case 62 unless the hooking of the hooking portion 82 is intentionally released.

Likewise, the second upper case 71 has a convex portion 81. The convex portion 81 is a projection on the outer peripheral surface 71a located radially outward of the second upper case 71. The lower surface of the projection 81 on the outer peripheral surface 71a inclines the outer peripheral side upward. On the other hand, the second lower case 72 has a hook portion 82. The hook portion 82 has elasticity and is located on the outer circumferential surface 72a on the radially outer side of the second lower case 72. The hook portion 82 has a curved shape that protrudes from a position on the outer peripheral surface 72a toward the second upper case 72 side and is bent along the outer shape of the convex portion 81. The outer peripheral surface 71a of the second upper case 71 and the outer peripheral surface 72a of the second lower case 72 are included in the outer peripheral surface 5a of the housing 5.

When the second lower case 72 is brought closer to the second upper case 71 side from the lower side in the axial direction, the convex portion 81 of the second upper case 71 pushes up the hook portion 82 of the second lower case 72, and the hook portion 82 is slightly elastically deformed. Immediately after the upper end of the hooking portion 82 in the axial direction passes the projection 81, the projection 81 releases the hooking portion 82 from being pushed up, and therefore the hooking portion 82 returns to the state before being elastically deformed by the restoring force and hooks onto the projection 81. Thus, the second lower case 72 is fixed to the second upper case 71, and the second lower case 72 does not fall off in the axial direction downward with respect to the second upper case 71 unless the hooking of the hooking portion 82 is intentionally released.

In this way, the first upper case 61 and the first lower case 62, and the second upper case 71 and the second lower case 72 are fixed by hooking the hook 82 to the protrusion 81. The structure in which the two members are fastened together by the elastic convex portion 81 and the hook portion 82 is referred to as a snap-fit portion 8.

Therefore, in the above example, the first upper case 61 and the second upper case 71 are fixed to the first lower case 62 and the second lower case 72 by snap-fitting portions, respectively. In this case, the first upper case 61 and the first lower case 62 can be easily connected by a simple structure using the snap-fit portion 8, and the second upper case 71 and the second lower case 72 can be easily connected. Therefore, the ease of assembly of the casing 5 and the blower 1 can be improved.

The first upper case 61 and the first lower case 62, and the second upper case 71 and the second lower case 72 may be fixed by screw fixation, an adhesive, or the like.

Further, a plurality of flanges 9 are provided at the lower end of the outer peripheral surface of the first lower case 62 and the upper end of the outer peripheral surface of the second upper case 71. The flange 9 of the first lower casing 62 and the flange 9 of the second upper casing 71 are fixed by screws, whereby the first impeller casing 6 and the second impeller casing 7 are connected and fixed in the axial direction. The first lower case 62 and the second upper case 71 may be fixed to each other by snap-fitting, an adhesive, or the like.

(1-4. details of impeller)

Next, details of the first impeller 3 and the second impeller 4 housed in the first impeller casing 6 and the second impeller casing 7, respectively, will be described mainly with reference to fig. 5 to 7.

The first impeller 3 has a first impeller base 31, a first shroud 33, and a plurality of first blade portions 32. The first impeller base 31 is a disk-shaped flat plate for supporting the plurality of first blade portions 32. A first fixing portion 34 that is fixed to one end of the shaft 2a is formed at the center of the first impeller base 31. The first fixing portion 34 may be fitted into the center of the first impeller base 31, or may be formed integrally with the first impeller base 31.

The plurality of first vane portions 32 are fixed to the first impeller base 31 at equal intervals in the circumferential direction at positions radially outward of the first fixing portions 34. The first shroud 33 has a first opening 33a having a diameter larger than that of the first air intake port 51, and is provided so as to sandwich the plurality of first vane portions 32 between the first shroud 33 and the first impeller base 31.

The second impeller 4 has a second impeller base 41, a second shroud 43, and a plurality of second vane portions 42. The second impeller base 41 is a disk-shaped flat plate for supporting the plurality of second blade portions 42. A second fixing portion 44 fixed to the other end of the shaft 2a is formed at the center of the second impeller base 41. The second fixing portion 44 may be fitted into the center of the second impeller base 41, or may be formed integrally with the second impeller base 41.

The plurality of second vane portions 42 are fixed to the second impeller base 41 at equal intervals in the circumferential direction at positions radially outward of the second fixing portions 44. The second shroud 43 has a second opening 43a having a larger diameter than the second inlet 52, and is provided so as to sandwich the plurality of second vane portions 42 between the second shroud 43 and the second impeller base 41.

In the present embodiment, the number of the first blade portions 32 of the first impeller 3 is the same as the number of the second blade portions 43 of the second impeller 4. In addition, the circumferential position of each first blade portion 32 is the same as the circumferential position of each second blade portion 42. That is, the first impeller 3 and the second impeller 4 have the same number of first blade portions 32 and second blade portions 42, respectively, and the circumferential positions of the first blade portions 32 of the first impeller 3 are the same as the circumferential positions of the second blade portions 42 of the second impeller 4.

(1-5. action)

Next, an operation based on the configuration of the blower 1 will be described with reference to fig. 8, 9, and 10 in addition to fig. 6 and 7. Fig. 8 is a perspective view of the blower 1 in a state in which the first upper case 61 is omitted from illustration. Fig. 9 is a perspective view of the blower 1 in a state in which the first upper case 61, the first lower case 62, and the second upper case 71 are not shown. Fig. 10 is a plan view of the blower 1 in a state where the first upper case 61 is not shown. In these figures, the arrows indicated by thick lines indicate the direction in which the air flows. In other drawings, the arrow shown by the thick line indicates the direction in which the air flows, similarly. That is, the thick line arrows in fig. 8 and 10 indicate the blowing direction of the air flowing in the first air tunnel 54, and the thick line arrows in fig. 9 indicate the blowing direction of the air flowing in the second air tunnel 55.

When the first impeller 3 and the second impeller 4 are rotated by the motor 2, air is sucked into the blower 1 from the first air inlet 51 and the second air inlet 52 in the axial direction, respectively. More specifically, air is sucked in from the first air intake port 51 toward the axially lower side by the rotation of the first impeller 3 and enters the first air tunnel 54. The air introduced into the first air tunnel 54 travels radially outward by the first impeller 3, and then flows in the circumferential direction toward the air outlet 53.

On the other hand, the rotation of the second impeller 4 causes air to be sucked in from the second air inlet 52 upward in the axial direction and to enter the second air channel 55. The air introduced into the second air tunnel 55 travels radially outward via the second impeller 4, and then flows in the circumferential direction toward the air outlet 53. The air flowing through the first air tunnel 54 and the air flowing through the second air tunnel 55 merge in the vicinity of the air blowing port 53. The merged air is discharged to the outside through the one air outlet 53.

Here, as shown in fig. 1, 8, 9, and the like, the first air tunnel 54 and the second air tunnel 55 have a structure in which the upstream side is open because they have a first opening portion 57 and a second opening portion 58 at positions on the most upstream side in the air flow direction in the circumferential direction, respectively. Thus, even if the first impeller 3 and the second impeller 4 rotate, it is possible to reduce the occurrence of a large negative pressure on the upstream side of the first air channel 54 and the second air channel 55. Therefore, the occurrence of noise due to the negative pressure can be reduced.

< 2. Structure and Effect relating to increase of blowing air quantity

In the configuration in which the first air tunnel 54 has the first opening portion 57 on the upstream side as described above, the upstream side of the first air tunnel 54 is spatially connected to the downstream side of the first air tunnel 54 via the first opening portion 57 outside the first air tunnel 54. In the configuration in which second air tunnel 55 has second opening 58 on the upstream side, the upstream side of second air tunnel 55 is spatially connected to the downstream side of second air tunnel 55 through second opening 58 outside second air tunnel 55.

Therefore, there is a possibility that air flowing from the upstream side toward the downstream side in the circumferential direction inside the first air tunnel 54 and the second air tunnel 55 may again flow back into the first air tunnel 54 or the second air tunnel 55 through the first opening portion 57 or the second opening portion 58, thereby reducing the amount of blowing air blown from the blowing port 53.

However, the following configuration or setting is adopted in combination with the blower 1, so that the above-described decrease in the amount of blown air can be suppressed, and the amount of blown air can be increased as compared with a case where the above-described configuration or setting is not adopted.

(2-1. setting about thickness of wall portion)

For convenience of the following description, a portion of the wall portion 56 shown in fig. 6 located on the upstream side in the air flow direction, that is, a portion closer to the start end 56U (see fig. 3) is denoted by reference numeral 56M. In addition, in the wall portion 56 shown in fig. 6, a portion located on the downstream side in the air flow direction, that is, a portion closer to the terminal end 56D is denoted by reference numeral 56N. In the wall portion shown in fig. 7, a portion different from the terminal 56D is denoted by reference numeral 56P. Further, the circumferential positional relationship of the start end 56U, the portion 56M, the portion 56P, the portion 56N, and the end 56D of the wall portion 56 is as shown in fig. 10. That is, the start end 56U, the portion 56M, the portion 56P, the portion 56N, and the end 56D of the wall portion 56 are arranged in this order from the upstream side toward the downstream side in the direction of air flow in the circumferential direction.

Further, the axial thicknesses of the start end 56U, the portion 56M, the portion 56P, the portion 56N, and the end 56D of the wall portion 56 are TU, T4, T3, T2, and T1, respectively. In this case, the thickness of the wall 56 in the axial direction is, for example, mm. In the present embodiment, the corner of the start end 56U is chamfered (see fig. 1 and the like). In this case, the thickness TU of the leading end 56U in the axial direction is the thickness of the axially thickest part of the chamfered parts of the leading end 56U.

In the present embodiment, the thickness of the wall portion 56 in the axial direction is set as follows. That is, the thickness of the wall portion 56 in the axial direction becomes thinner from the start end 56U of the wall portion 56 located on the upstream side in the air flow direction in the circumferential direction toward the end 56D of the wall portion 56 located on the downstream side. Therefore, the axial thicknesses of the start end 56U, the portion 56M, the portion 56P, the portion 56N, and the end 56D of the wall portion 56 are TU > T4 > T3 > T2 > T1.

In this way, the thickness of the wall portion 56 that axially separates the first air channel 54 and the second air channel 55 becomes thinner from the circumferential start end 56U toward the circumferential end 56D. Therefore, the respective air flows in the circumferential direction in the first air tunnel 54 and the second air tunnel 55 converge toward the inner side in the axial direction, i.e., the central portion side of the blower 1, from the start end 56U side toward the end 56D side of the wall portion 56.

Accordingly, each of the air discharged from the downstream sides of the first air tunnel 54 and the second air tunnel 55 collides with an end face of the start end 56U having a thickness larger than the thickness of the terminal end 56D of the wall portion 56, that is, a surface P (see fig. 1 and 2) exposed on the side of the air blowing port 53 at the start end 56U. Then, the air easily travels toward the air blowing port 53.

Therefore, even in the configuration in which the first air tunnel 54 and the second air tunnel 55 have the first opening 57 and the second opening 58, respectively, to reduce the noise, as described above, the air can be guided to the air blowing port 53 side. Therefore, it is possible to reduce the possibility that the respective air discharged from the downstream sides of the first air tunnel 54 and the second air tunnel 55 reenters the first air tunnel 54 or the second air tunnel 55 through the first opening portion 57 or the second opening portion 58.

Accordingly, even in the configuration in which the first opening 57 and the second opening 58 are provided to reduce the noise, the respective air discharged from the downstream sides of the first air tunnel 54 and the second air tunnel 55 can be efficiently guided to the air blowing port 53 and efficiently discharged from the air blowing port 53. This can increase the flow rate of the air blown by the blower 1. That is, the amount of air blown by the blower 1 can be increased while reducing the occurrence of noise due to negative pressure at the upstream end portions of the first air tunnel 54 and the second air tunnel 55.

Further, since there is only one air blowing port 53, the respective air collected in the axial central portion by the thickness setting of the wall portion 56, that is, the respective air flowing through the first air tunnel 54 and the second air tunnel 55 can be directly discharged from the one air blowing port 53 in a collected state. This can suppress the dispersion of air discharged from the air blowing port 53 and increase the amount of air blown in one direction. Further, when there is only one air blowing port 53, the respective air collected on the center portion side in the axial direction can be directly discharged, and therefore, a structure for collecting the respective air in the axial direction, that is, a structure in which the thickness of the wall portion 56 is changed as described above can be easily adopted.

Further, since the thickness of the wall portion 56 becomes thinner from the starting end 56U toward the ending end 56D in the circumferential direction, the ratio (TU/T1) of the thickness TU of the starting end 56U of the wall portion 56 to the thickness T1 of the ending end 56D in the axial direction exceeds 1, but from the viewpoint of more easily exhibiting the above-described operational effects, TU/T11 is preferably 1.5 or more, more preferably 2.0 or more, and still more preferably 3.0 or more. The thickness of the wall portion 56 in the axial direction may change at a constant rate from the upstream side to the downstream side in the circumferential direction, may change more abruptly on the downstream side than on the upstream side, or may change more abruptly on the upstream side than on the downstream side. However, from the viewpoint of smoothly flowing air in the first air tunnel 54 and the second air tunnel 55, the thickness of the wall portion 56 in the axial direction preferably changes at a constant rate from the upstream side to the downstream side in the circumferential direction.

(2-2. symmetry about impeller and impeller housing)

As described above, in the present embodiment, the first blade portions 32 of the first impeller 3 and the second blade portions 42 of the second impeller 4 have the same number of blades and the same circumferential position. Thus, when the first impeller 3 and the second impeller 4 are rotated at the same rotational speed, their rotations are synchronized. This increases the force for pushing out the air from the air blowing port 53, and can further increase the air blowing flow rate. In addition, when the rotation of the first impeller 3 and the rotation of the second impeller 4 are synchronized, noise is reduced as compared with the case of non-synchronization.

In the present embodiment, the first impeller 3 and the second impeller 4 are symmetrical with respect to the plane L, and the first impeller housing 6 having at least the first air channel 54 and the second impeller housing 7 having at least the second air channel 55 are symmetrical with respect to the plane L. This makes it possible to equalize the blowing performance of each air in the first impeller casing 6 and the second impeller casing 7. Therefore, the force for pushing out the air from the air blowing port 53 is increased, and the air blowing flow rate can be further increased. Further, since the difference in the flow rates of the air blown by the first impeller casing 6 and the second impeller casing 7 is small, the occurrence of noise due to the difference in the flow rates of the air blown can be reduced.

< 3. Structure for reducing turbulence >

In the present embodiment, the following configuration is adopted for the blower 1, and turbulence generated in the vicinity of the air blowing port 53 during air blowing can be reduced, thereby reducing noise generation due to turbulence. Hereinafter, the description will be made in more detail.

(3-1. positional relationship between the end of the wall portion and the air supply opening)

As shown in fig. 10, the end 56D of the wall 56 is located upstream of the air blowing port 53 in the air flow direction. By the positional relationship between the terminal 56D and the air blowing port 53, the air flowing in the circumferential direction in the first air tunnel 54 and heading for the air blowing port 53 and the air flowing in the circumferential direction in the second air tunnel 55 and heading for the air blowing port 53 can be merged between the terminal 56D and the air blowing port 53, that is, inside the housing 5. This enables the merged air to be discharged from the blowing port 53 after the flow direction of the merged air is aligned in the casing 5. As a result, the generation of turbulence in the air blowing port 53 and the generation of noise due to the turbulence can be reduced.

In addition, to achieve the main object of the present embodiment of increasing the amount of blowing air, the terminal end 56D of the wall portion 56 may be connected to the blowing port 53.

(3-2. positional relationship between the end of the wall portion and the edge portion)

As shown in fig. 10, the housing 5 has a rim 59. The edge portion 59 forms a downstream edge of the blowing port 53. An inner surface 59a, which is a radially inner surface of the edge portion 59, is a flat surface extending from the terminal end 56D of the wall portion 56 in the circumferential tangential direction of the outer peripheral surface 5a when viewed in the axial direction. That is, the casing 5 has a rim 59 forming a downstream edge of the air blowing port 53, and a radially inner surface of the rim 59 has an inner surface 59a extending in the circumferential tangential direction from the terminal end 56D of the wall 56.

As described above, since the casing 5 has the edge portion 59 and the edge portion 59 has the inner surface 59a, the respective air flowing in the first air channel 54 and the second air channel 55 travels in the circumferential tangential direction along the inner surface 59a of the edge portion 59, that is, along the plane perpendicular to the radial direction, on the downstream side of the air blowing port 53. This can improve the straightness of the air discharged from the air outlet 53, reduce the occurrence of turbulence in the air outlet 53, and reduce the occurrence of noise due to the turbulence. Further, since the straightness of the air is improved, the flow rate of the air blown in one direction can be increased.

In particular, the edge portion 59 protrudes toward the air-blowing port 53 from a position radially outward of the terminal end 56D of the wall portion 56. Thereby, the air flowing through the first air channel 54 and the second air channel 55 travels in the projecting direction of the edge portion 59. That is, the air travels straight from the terminal end 56D of the wall 56 toward the air blowing port 53 along the inner surface 59a of the edge 59. Therefore, the straightness of the air discharged from the air blowing port 53 can be improved, and the air flow rate in one direction can be increased.

< 4. air supply device

The blower 1 of the present embodiment can be applied to a blower device such as an air cleaner. Hereinafter, a blowing device to which the blower 1 can be applied will be described.

(4-1. schematic construction of blowing device)

Fig. 11 is a perspective view of air blower 100, and fig. 12 is a perspective view of air blower 100 with the cabinet and the internal air blower omitted. Fig. 13 is an exploded perspective view of air blower 100 with the casing omitted from illustration, and fig. 14 is a partial perspective view of air blower 100 during air blowing. The blower 100 includes a casing 200 and a filter 300 in addition to the blower 1 described in the present embodiment. The case 200 houses the blower 1 therein. Further, the case 200 has a louver 201. The louver 201 is a discharge port for guiding air discharged from the blower 1 inside the casing 200 to the outside.

The filter 300 is a dust collecting filter for removing dust, pollen, and the like in the air, and is disposed axially outward of the first air inlet 51 and the second air inlet 52 of the blower 1 disposed in the casing 200, respectively. The Filter 300 includes, for example, an activated carbon Filter 301 and a HEPA Filter (High Efficiency Particulate Air Filter) 302. The activated carbon filter 301 is a general dust collecting filter used in an air cleaner. The HEPA filter 302 is a high-performance dust collecting filter having a higher dust collecting capacity than the activated carbon filter 301. The filter 300 may have at least one of an activated carbon filter 301 and a HEPA filter 302. The Filter 300 may be a dust collecting Filter having higher performance such as an Ultra Low permeability Air Filter (ULPA Filter).

That is, the air blowing device 100 includes: a blower 1; a case 200 that houses the blower 1; and a filter 300 disposed in the casing 200 at a position facing the first intake port 51 and the second intake port 52 of the blower 1. By disposing the filters 300 at positions facing the first air inlet 51 and the second air inlet 52, which are two air inlets of the blower 1, respectively, it is possible to remove dust contained in air sucked from the respective air inlets by the respective filters 300, and realize the blower device 100, for example, an air cleaner, which discharges clean air from the louver 201.

(4-2. rotating structure of blower)

The blower device 100 includes a rotation mechanism 400, and the rotation mechanism 400 rotates the blower 1 with respect to the casing 200 to adjust the blowing direction of the blower 1. The details of the rotating mechanism 400 will be described below.

Fig. 15 and 16 are side views of the interior of the housing 200 of the blower device 100 as viewed from the second air inlet 52 side. Fig. 15 shows a state before the blower 1 rotates. Fig. 16 shows a state after the blower 1 is rotated. In fig. 15 and 16, for convenience, the outer shape of the case 200 is shown by a broken line. The rotation mechanism 400 includes a main body-side gear 401, a drive gear 402, and a support roller 403.

The main body-side gear 401 is formed on the outer peripheral surface 5a of the blower 1 in the circumferential direction. The main body-side gear 401 may be formed on the outer circumferential surface 5a over the entire circumferential range, or may be formed only in a part of the circumferential direction. The drive gear 402 is engaged with the main body-side gear 401 and rotates about a rotation shaft 402a arranged parallel to the center axis C. The rotary shaft 402a is supported by the housing 200 via a bearing (not shown). The support roller 403 is a roller that supports the blower 1 so as to be rotatable in the circumferential direction with respect to the casing 200. The support roller 403 is supported by the case 200 so as to be parallel to the central axis C of the blower 1, and supports the blower 1 by contacting the outer peripheral surface 5a of the blower 1. In the present embodiment, three support rollers 403 are provided, but the number is not limited to three as long as the number can support the blower 1.

That is, the rotation mechanism 400 includes: a main body-side gear 401 formed on the outer peripheral surface 5a of the blower 1 along the circumferential direction; a drive gear 402 that is meshed with the main body-side gear 401 and rotates about a rotation shaft 402a parallel to the center axis C; and a support roller 403 that supports the blower 1 rotatably with respect to the casing 200. In this structure, for example, when the drive gear 402 rotates in the E direction of fig. 15, the rotational driving force of the drive gear 402 is transmitted to the blower 1 via the main body side gear 401, whereby the blower 1 rotates in the G direction. This changes the blowing direction of the air blown from the blowing port 53 of the blower 1 downward. On the other hand, when the drive gear 402 rotates in the F direction of fig. 16, the rotational driving force of the drive gear 402 is transmitted to the blower 1 via the main body side gear 401, whereby the blower 1 rotates in the H direction. Thereby, the blowing direction of the air blown from the blowing port 53 of the blower 1 is changed upward.

As described above, since the blower 1 includes the rotation mechanism 400, the blower 1 can be rotated by the rotation mechanism 400, and the direction of the air discharged from the air outlet 53 of the blower 1 can be freely changed, thereby improving convenience.

For example, the outer peripheral surface of the casing 5 of the blower 1 of the present embodiment is preferably cylindrical extending in the direction of the central axis C. At this time, the plurality of support rollers 403 hold the casing 5, which is a cylindrical surface, and can easily rotate the blower 1. In particular, according to the above configuration of the turning mechanism 400, the blower 1 can be turned in the circumferential direction with respect to the casing 200 in a state where the blower 1 is supported by the support rollers 403. This makes it possible to easily adjust the blowing direction of the blower 1 in a plane perpendicular to the center axis C of the blower 1.

While the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications can be made without departing from the scope of the present invention. The above embodiments and modifications thereof can be combined as appropriate.

[ industrial applicability ]

The blower of the present invention can be used in a blower device such as an air cleaner.

Claims

1. An air blower having:

a motor having a shaft rotating about a central axis;

a first impeller and a second impeller connected to an end of one side in an axial direction and an end of the other side in the axial direction of the shaft, respectively; and

a housing that houses the motor, the first impeller, and the second impeller therein,

the housing has:

a first intake port located on one axial side of the first impeller;

a second air inlet port located on the other axial side of the second impeller;

a supply port located radially outward of the shaft relative to the first impeller and the second impeller;

a first wind tunnel that communicates with the first intake port, extends in the circumferential direction of the shaft, and communicates with the air supply port on the most downstream side in the direction of air flow in the circumferential direction of the first wind tunnel;

a second air tunnel that communicates with the second air intake port, extends in the circumferential direction of the shaft, and communicates with the air supply port on the most downstream side in the direction of air flow in the circumferential direction of the second air tunnel; and

a wall portion extending in a circumferential direction and axially separating the first wind tunnel and the second wind tunnel,

the first air tunnel and the second air tunnel have a first opening and a second opening at positions on the most upstream side in the direction of air flow in the circumferential direction,

the thickness of the wall portion in the axial direction becomes thinner from a start end of the wall portion located on an upstream side in the direction of the air flow in the circumferential direction toward a terminal end of the wall portion located on a downstream side.

2. The blower according to claim 1, wherein,

the terminal end of the wall portion is located upstream of the air blowing port in the air flow direction.

3. The blower according to claim 1, wherein,

the first impeller and the second impeller have the same number of first blade portions and second blade portions, respectively,

the positions in the circumferential direction of the first blade portions of the first impeller are the same as the positions in the circumferential direction of the second blade portions of the second impeller.

4. The blower according to claim 1, wherein,

the housing has:

a first impeller housing that houses the first impeller; and

a second impeller housing that houses the second impeller,

the first impeller casing has the first air intake port, the first wind tunnel, a first divided wall that divides the wall into two parts, and a first divided air blowing port that divides the air blowing port into one of the two parts,

the second impeller casing has the second air inlet, the second air tunnel, a second divided wall that divides the wall into the other of the two parts, and a second divided air outlet that divides the air outlet into the other of the two parts.

5. The blower according to claim 4, wherein,

the first impeller and the first impeller housing and the second impeller housing are in a shape symmetrical with respect to a plane that is perpendicular to the center axis and passes through a center of an axial direction of the wall portion.

6. The blower according to claim 4, wherein,

when one axial side is set to be up and the other axial side is set to be down,

the first impeller housing has:

a first upper casing having the first air intake; and

a first lower case axially connected with the first upper case,

the second impeller shell has:

a second lower case having the second suction port; and

a second upper housing connected in an axial direction with the first lower housing and the second lower housing,

the wall portion is located at the first lower case and the second upper case.

7. The blower according to claim 6, wherein,

the first wind tunnel is provided with a first upper wind tunnel communicated with the first air suction port and a first lower wind tunnel communicated with the first upper wind tunnel,

the second wind tunnel is provided with a second lower wind tunnel communicated with the second air suction port and a second upper wind tunnel communicated with the second lower wind tunnel,

the first upper housing has the first upper air tunnel,

the first lower housing has the first lower air tunnel,

the second upper housing has the second upper air tunnel,

the second lower housing has the second lower wind tunnel,

the wall portion axially separates the first lower wind tunnel of the first lower housing and the second upper wind tunnel of the second upper housing.

8. The blower according to claim 6, wherein,

the first upper case and the second upper case are fixed to the first lower case and the second lower case, respectively, by snap-fit portions.

9. The blower according to claim 1, wherein,

the casing has a rim portion forming a downstream side rim of the air blowing port,

a radially inner face of the rim has an inner surface extending from the terminal end of the wall portion in a circumferential tangential direction.

10. The blower according to claim 9, wherein,

the edge portion protrudes toward the air-blowing port from a position radially outward of the terminal end of the wall portion.

11. An air supply device includes:

the blower of any one of claims 1 to 10;

a case that houses the blower; and

and a filter disposed in the case at a position facing the first intake port and the second intake port of the blower.

12. The air supply arrangement of claim 11,

the blower device has a rotating mechanism for adjusting the blowing direction of the blower by rotating the blower with respect to the casing.

13. The air supply arrangement of claim 12,

the rotating mechanism has:

a main body-side gear formed on an outer peripheral surface of the blower in a circumferential direction;

a drive gear that is meshed with the main body-side gear and rotates about a rotation axis parallel to the central axis; and

and a support roller that supports the blower so as to be rotatable with respect to the casing.