JP6896091B2 - Multi-wing blower - Google Patents

Description

The present invention relates to a multi-blade blower equipped with an impeller.

Patent Document 1 describes an impeller of a centrifugal fan. The blade of this impeller has a turbofan shape that is convex on the pressure surface side on the inner peripheral side of the impeller, and has a sirocco fan shape that is concave on the pressure surface side on the outer peripheral side of the impeller. There is.

Japanese Unexamined Patent Publication No. 2005-69183

In an impeller as described in Patent Document 1, in order to prevent the air flow from being largely separated from the wing, from the inner peripheral end which is the front edge of the wing to the outer peripheral end which is the trailing edge of the wing. It is necessary to prevent the radius of curvature of the warp of the wing from becoming small. If a large radius of curvature of the warp of the blade is secured, the blade length becomes long. Therefore, when maintaining the outer diameter of the impeller, it is necessary to bring the inner peripheral end of the blade closer to the rotation axis. When the inner peripheral end of the blade is brought closer to the rotation axis, the area ratio occupied by the inner peripheral end of the blade increases, and the inlet portion of the air flow path between the blades becomes narrower. Therefore, when the air flowing in the direction of the rotation axis flows into the air flow path between the blades, the contraction at the inlet of the air flow path between the blades becomes excessive, so that the efficiency of the fan is lowered. was there.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a multi-blade blower capable of improving efficiency.

The multi-blade blower according to the present invention is a multi-blade blower including an impeller that rotates about a rotation axis, and the impeller includes a plurality of blades arranged in a circumferential direction around the rotation axis. In the first cross section of the impeller, which has a main plate that supports the plurality of blades from one side in a direction along the rotation axis and is cut by a first plane perpendicular to the rotation axis, the plurality of blades. Each of the blades has an inner peripheral end and an outer peripheral end provided on the outer peripheral side of the inner peripheral end and inclined forward in the rotational direction of the impeller, and the plurality of blades. Has a plurality of first wings and a plurality of second wings, and in the first cross section, each of the plurality of first wings is derived from the respective blade lengths of the plurality of second wings. Also has a long blade length, and in the first cross section, the distance between the rotation shaft and the inner peripheral end of each of the plurality of first blades is determined by the rotation shaft and the plurality of second blades, respectively. It is shorter than the distance to the inner peripheral end of the plurality of first wings, and at least of the plurality of second wings is between the two first wings adjacent to each other in the circumferential direction. One second wing is arranged, and each of the plurality of first wing is composed of a part closer to the main plate in the direction along the rotation axis, and is formed so that the wing length becomes longer as it approaches the main plate. a first portion, consists portions other than the first portion, possess a second portion blade length is formed to have a constant length in the direction along the rotational axis of the first portion The length of the second portion is shorter than the length in the direction along the rotation axis, and the entire main plate is composed of a plane perpendicular to the rotation axis .

According to the present invention, at least one second wing having a wingspan shorter than that of the first wing is arranged between the two first wings adjacent to each other in the circumferential direction, and therefore between the two first wings. It is possible to prevent the inlet portion of the air flow path formed in the above from being narrowed. Therefore, the contraction at the inlet of the air flow path between the blades can be relaxed, so that the efficiency of the multi-blade blower can be improved.

FIG. 5 is an external view schematically showing a configuration in which a multi-blade blower according to a first embodiment of the present invention is viewed along a rotation shaft 11. It is a figure which shows typically the II-II cross section of FIG. It is a perspective view which shows the structure of the impeller 10 of the multi-blade blower which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the IV-IV cross section of FIG. It is sectional drawing which shows the VV cross section of FIG. It is a figure explaining the shape of the 1st wing 12A in the 1st cross section in the multi-blade blower which concerns on Embodiment 1 of this invention.

Embodiment 1.
The multi-blade blower according to the first embodiment of the present invention will be described. FIG. 1 is an external view schematically showing a configuration of a multi-blade blower according to the present embodiment as viewed along a rotation shaft 11. FIG. 2 is a diagram schematically showing a cross section of II-II of FIG. As shown in FIGS. 1 and 2, the multi-blade blower includes an impeller 10 that rotates about a rotating shaft 11, a casing 30 that houses the impeller 10, and a drive motor 40 that drives the impeller 10. Have.

The casing 30 has a scroll wall 31, a suction port 32, and an outlet 33. The scroll wall 31 has a scroll shape such that an enlarged air passage is formed in a cross section perpendicular to the rotation axis 11. The suction port 32 is an opening formed by a bell mouth-shaped annular portion centered on the rotation shaft 11. The suction port 32 is formed on one side surface of the casing 30. The air outlet 33 is an opening formed in a cross section perpendicular to the rotation axis 11 so as to face the tangential direction of the scroll wall 31.

The drive motor 40 is arranged adjacent to the side surface of the casing 30 on the side opposite to the side surface on which the suction port 32 is formed. The motor shaft 41 of the drive motor 40 extends on the rotating shaft 11, penetrates the side surface of the casing 30, and is inserted into the casing 30.

The impeller 10 has a plurality of blades 12 arranged in the circumferential direction about the rotation shaft 11, and a main plate 13 that supports the plurality of blades 12 from one side in the direction along the rotation shaft 11. The main plate 13 is arranged along the side surface of the casing 30 on the drive motor 40 side so as to be perpendicular to the rotating shaft 11. A motor shaft 41 inserted inside the casing 30 is fixed to the central portion of the main plate 13.

When the drive motor 40 is operated, the plurality of blades 12 rotate about the rotation shaft 11 via the motor shaft 41 and the main plate 13. As a result, the outside air is sucked into the impeller 10 from the suction port 32 and blown into the casing 30 by the pressurizing action of the impeller 10. The air blown into the casing 30 is decelerated by the expanded air passage formed by the scroll wall 31 to recover the static pressure, and is blown out from the air outlet 33 to the outside.

FIG. 3 is a perspective view showing the configuration of the impeller 10 of the multi-blade blower according to the present embodiment. FIG. 4 is a cross-sectional view showing an IV-IV cross section of FIG. The cross section shown in FIG. 4 is the first cross section of the impeller 10 in which the portion of the impeller 10 near the main plate 13 is cut at the first plane 51 perpendicular to the rotating shaft 11. FIG. 5 is a cross-sectional view showing a VV cross section of FIG. The cross section shown in FIG. 5 is a second cross section of the impeller 10 in which a portion of the impeller 10 near the suction port 32 is cut at a second plane 52 perpendicular to the rotating shaft 11.

As shown in FIGS. 3 to 5, the plurality of wings 12 have a plurality of first wings 12A and a plurality of second wings 12B. The first blade 12A has an inner peripheral end 14A and an outer peripheral end 15A provided on the outer peripheral side of the inner peripheral end 14A and inclined forward in the rotation direction of the impeller 10. The inner peripheral end 14A serves as the leading edge of the first wing 12A, and the outer peripheral end 15A serves as the trailing edge of the first wing 12A. The second blade 12B has an inner peripheral end 14B and an outer peripheral end 15B which is provided on the outer peripheral side of the inner peripheral end 14B and is inclined forward in the rotation direction of the impeller 10. The inner peripheral end 14B serves as the front edge of the second wing 12B, and the outer peripheral end 15B serves as the trailing edge of the second wing 12B.

The wingspan of the first blade 12A is equal to the wingspan of the second blade 12B at the portion closer to the suction port 32 in the direction along the rotation axis 11 (see FIG. 5). On the other hand, in the portion closer to the main plate 13 in the direction along the rotation axis 11, the wingspan of the first wing 12A is longer than the wingspan of the second wing 12B (see FIG. 4), and the closer to the main plate 13. It's getting longer. As described above, in the present embodiment, the wingspan of the first blade 12A is longer than the blade length of the second blade 12B at least in a part of the direction along the rotation axis 11.

In the first cross section near the main plate 13 shown in FIG. 4, the distance between the rotating shaft 11 and the inner peripheral end 14A of the first wing 12A, that is, the inner diameter of the first wing 12A is ri_Ab. The distance between the rotating shaft 11 and the outer peripheral end 15A, that is, the outer diameter of the first blade 12A is ro_Ab. The difference between the distance ro_Ab and the distance ri_Ab is the wingspan L1b of the first blade 12A in the first cross section (L1b = ro_Ab-ri_Ab). Here, in a general multi-blade blower, the blade length in the cross section perpendicular to the rotation axis is shorter than the span of the blade in the rotation axis direction. Also in this embodiment, the maximum wingspan of the first wing 12A, that is, the wing length at the end of the first wing 12A near the main plate 13, is the width dimension W in the rotation axis direction of the first wing 12A (see FIG. 2). Is shorter than.

Further, in the first cross section, the distance between the rotating shaft 11 and the inner peripheral end 14B of the second wing 12B, that is, the inner diameter of the second wing 12B is ri_Bb larger than the distance ri_Ab (ri_Bb> ri_Ab). The distance between the rotating shaft 11 and the outer peripheral end 15B, that is, the outer diameter of the second blade 12B is ro_Bb equal to the distance ro_Ab (ro_Bb = ro_Ab). The difference between the distance ro_Bb and the distance ri_Bb is the wingspan L2b of the second blade 12B in the first cross section (L2b = ro_Bb-ri_Bb). The wingspan L2b of the second blade 12B in the first cross section is shorter than the wingspan L1b of the first blade 12A in the same cross section (L2b <L1b).

The exit angle of the first wing 12A in the first cross section is βbo_Ab. The exit angle of the second wing 12B in the same cross section is βbo_Bb. The exit angle βbo_Bb of the second wing 12B is equal to the exit angle βbo_Ab of the first wing 12A (βbo_Bb = βbo_Ab).

On the other hand, in the second cross section near the suction port 32 shown in FIG. 5, the distance between the rotating shaft 11 and the inner peripheral end 14A of the first wing 12A is ri_Ai. The distance ri_Ai is longer than the distance ri_Ab between the rotating shaft 11 and the inner peripheral end 14A of the first wing 12A in the first cross section (ri_Ai> ri_Ab). The distance between the rotating shaft 11 and the outer peripheral end 15A of the first blade 12A is ro_Ai. The difference between the distance ro_Ai and the distance ri_Ai is the wingspan L1i of the first blade 12A in the second cross section (L1i = ro_Ai-ri_Ai).

Further, in the second cross section, the distance between the rotating shaft 11 and the inner peripheral end 14B of the second blade 12B is ri_Bi. The distance ri_Bi is equal to the distance ri_Ai between the rotating shaft 11 and the inner peripheral end 14A of the first wing 12A in the same cross section (ri_Bi = ri_Ai). The distance between the rotating shaft 11 and the outer peripheral end 15B of the second blade 12B is ro_Bi. The distance ro_Bi is equal to the distance ro_Ai between the rotating shaft 11 and the outer peripheral end 15A of the first blade 12A in the same cross section (ro_Bi = ro_Ai). The difference between the distance ro_Bi and the distance ri_Bi is the wingspan L2i of the second blade 12B in the second cross section (L2i = ro_Bi-ri_Bi). The wingspan L2i of the second blade 12B in the second cross section is equal to the wingspan L1i of the first blade 12A in the same cross section (L2i = L1i).

Although not shown in FIG. 5, the outlet angle of the first wing 12A and the exit angle of the second wing 12B are equal even in the second cross section.

As shown in FIGS. 3 to 5, at least one second wing 12B is arranged between the two first wings 12A adjacent to each other in the circumferential direction. Therefore, the number of the second wings 12B is equal to or larger than the number of the first wings 12A. In the present embodiment, since the two second wings 12B are arranged between the two first wings 12A, the number of the second wings 12B is twice the number of the first wings 12A. ..

When viewed in parallel with the rotating shaft 11, the first wing 12A in the second cross section shown in FIG. 5 does not protrude from the contour of the first wing 12A in the first cross section shown in FIG. It overlaps with. Therefore, the relationships of ro_Ai ≦ ro_Ab, ri_Ai ≧ ri_Ab, and L1i ≦ L1b are satisfied.

Similarly, when viewed in parallel with the rotating shaft 11, the second wing 12B in the second cross section shown in FIG. 5 does not protrude from the contour of the second wing 12B in the first cross section shown in FIG. It overlaps with 2 wings 12B. Therefore, the relationships of ro_Bi ≦ ro_Bb, ri_Bi ≧ ri_Bb, and L2i ≦ L2b are satisfied.

FIG. 6 is a diagram illustrating the shape of the first blade 12A in the first cross section in the multi-blade blower according to the present embodiment. As shown in FIG. 6, the first wing 12A in the first cross section includes the outer peripheral wing portion 12A1 located on the outer peripheral side of the circle C1 which is in contact with the inner peripheral end 14B of the second wing 12B with the rotation axis 11 as the center. It has an inner peripheral side wing portion 12A2 located on the inner peripheral side of the circle C1.

The length of the chord wire 20 of the outer peripheral side wing portion 12A1 is defined as the chord length L_Ab1 of the outer peripheral side wing portion 12A1, and the maximum distance between the chord wire 20 and the warp line 22 of the outer peripheral side wing portion 12A1 is defined as the warp height d_Ab1 of the outer peripheral side wing portion 12A1. .. Here, the warp height in the direction opposite to the rotation direction of the impeller 10 is represented by a positive value, and the warp height in the rotation direction of the impeller 10 is represented by a negative value. Since the outer peripheral side wing portion 12A1 is warped in the direction opposite to the rotation direction of the impeller 10, the warp height d_Ab1 is a positive value (d_Ab1> 0). The ratio of the warp height d_Ab1 to the chord length L_Ab1 (d_Ab1 / L_Ab1) is defined as the warp ratio of the outer peripheral side wing portion 12A1.

Further, the length of the chord wire 21 of the inner peripheral side wing portion 12A2 is set to the chord length L_Ab2 of the inner peripheral side wing portion 12A2, and the maximum distance between the chord wire 21 and the warp line 23 of the inner peripheral side wing portion 12A2 is set to the inner peripheral side wing portion 12A2. The warp height is d_Ab2. In the present embodiment, since the inner peripheral side blade portion 12A2 is warped in the rotation direction of the impeller 10, the warp height d_Ab2 has a negative value (d_Ab2 <0). However, the inner peripheral side blade portion 12A2 may be warped in the direction opposite to the rotation direction of the impeller 10. The ratio of the warp height d_Ab2 to the chord length L_Ab2 (d_Ab2 / L_Ab2) is defined as the warp ratio of the inner peripheral side wing portion 12A2. At this time, the warp ratio (d_Ab1 / L_Ab1) of the outer peripheral side wing portion 12A1 is larger than the warp ratio (d_Ab2 / L_Ab2) of the inner peripheral side wing portion 12A2 (d_Ab1 / L_Ab1> d_Ab2 / L_Ab2).

As described above, the multi-blade blower according to the present embodiment is a multi-blade blower including an impeller 10 that rotates about a rotating shaft 11. The impeller 10 has a plurality of blades 12 arranged in the circumferential direction about the rotation shaft 11, and a main plate 13 that supports the plurality of blades 12 from one side in the direction along the rotation shaft 11. In the first cross section (for example, the cross section shown in FIG. 4) of the impeller 10 cut by the first plane 51 perpendicular to the rotation axis 11, each of the plurality of blades 12 has an inner peripheral end (for example, an inner peripheral end 14A). Alternatively, it has an inner peripheral end 14B) and an outer peripheral end (for example, outer peripheral end 15A or outer peripheral end 15B) provided on the outer peripheral side of the inner peripheral end and inclined forward in the rotation direction of the impeller 10. ing. The plurality of wings 12 have a plurality of first wings 12A and a plurality of second wings 12B. In the first cross section, each of the plurality of first wings 12A has a wingspan L1b longer than the wingspan L2b of each of the plurality of second wings 12B. In the first cross section, the distance ri_Ab between the rotating shaft 11 and the inner peripheral ends 14A of the plurality of first wings 12A is the distance ri_Bb between the rotating shaft 11 and the inner peripheral ends 14B of the plurality of second wings 12B. Is shorter than. At least one of the plurality of second wings 12B is arranged between the two first wings 12A adjacent to each other in the circumferential direction among the plurality of first wings 12A.

According to this configuration, since the wingspan L1b of the first wing 12A is longer than the wingspan L2b of the second wing 12B, the pressurizing action due to the centrifugal force can be enhanced at least in the first wing 12A. On the other hand, at least one second wing 12B having a wingspan shorter than that of the first wing 12A is arranged between the two first wings 12A adjacent to each other in the circumferential direction. As a result, it is possible to prevent the inlet portion of the air flow path formed between the two first blades 12A from narrowing, so that the contraction at the inlet portion of the air flow path between the blades can be alleviated. it can. Therefore, according to the above configuration, the efficiency of the multi-blade blower can be improved, and the required power of the multi-blade blower can be reduced.

Further, in the multi-blade blower according to the present embodiment, in the first cross section, each of the plurality of first blades 12A is in contact with the inner peripheral end 14B of each of the plurality of second blades 12B about the rotation shaft 11. It has an outer peripheral side wing portion 12A1 located on the outer peripheral side of the circle C1 and an inner peripheral side wing portion 12A2 located on the inner peripheral side of the circle C1. In each of the outer peripheral side wing portion 12A1 and the inner peripheral side wing portion 12A2, the ratio of the warp height to the chord length is defined as the warp ratio, and the warp height in the direction opposite to the rotation direction is represented by a positive value. The warp height is represented by a negative value. At this time, the warp ratio (d_Ab1 / L_Ab1) of the outer peripheral side wing portion 12A1 is larger than the warp ratio (d_Ab2 / L_Ab2) of the inner peripheral side wing portion 12A2.

According to this configuration, the angle difference between the air flow direction and the blade surface of the first blade 12A can be reduced at the inlet of the air flow path formed between the two first blades 12A. As a result, separation in the air flow path between the blades can be suppressed, so that the efficiency of the multi-blade blower can be further improved.

Further, in the multi-blade blower according to the present embodiment, the plane perpendicular to the rotation axis 11 and the distance from the main plate 13 is longer than the distance between the first plane and the main plate 13 is defined as the second plane 52. .. The distance ri_Ai between the rotating shaft 11 and the inner peripheral ends 14A of the plurality of first wings 12A in the second cross section (for example, the cross section shown in FIG. 5) of the impeller 10 cut by the second plane 52 is the above-mentioned first. The distance between the rotating shaft 11 in one cross section and the inner peripheral end 14A of each of the plurality of first wings 12A is longer than the distance ri_Ab.

According to this configuration, the inner diameter of the first blade 12A centered on the rotating shaft 11 is larger on the suction port 32 side of the impeller 10 than on the main plate 13 side of the impeller 10. Therefore, on the suction port 32 side of the impeller 10, the cross-sectional area of the air flow path that flows into the impeller 10 from the suction port 32 and flows along the rotation shaft 11 can be increased. As a result, the velocity component of the air flowing into the impeller 10 in the rotation axis 11 direction can be reduced, so that the loss when the flow of the air flowing into the impeller 10 is bent in the radial direction of the impeller 10. Can be reduced. Therefore, the efficiency of the multi-blade blower can be further improved. On the other hand, the air circulating inside the impeller 10 has a momentum in the direction of the rotating shaft 11 from the suction port 32 toward the main plate 13. Therefore, the air volume distribution of the air flowing out from the impeller 10 is biased toward the main plate 13 in the direction of the rotation axis 11. In the above configuration, since the wingspan of the first blade 12A is longer in the portion closer to the main plate 13, the pressurizing action in the first blade 12A can be enhanced in the portion where the air volume distribution is large. Therefore, the output of the multi-blade blower can be effectively improved.

Further, in the multi-blade blower according to the present embodiment, when viewed in parallel with the rotating shaft 11, each of the plurality of blades 12 in the second cross section is derived from the contours of the plurality of blades 12 in the first cross section. It overlaps with each of the plurality of wings 12 in the first cross section so as not to protrude.

According to this configuration, the main plate 13 and the plurality of blades 12 can be integrally formed by using a simple mold that opens in the direction of the rotation shaft 11. Therefore, the manufacturing cost of the multi-blade blower can be reduced.

Further, in the multi-blade blower according to the present embodiment, in the first cross section, the distance ro_Ab between the outer peripheral end 15A of each of the plurality of first blades 12A and the rotating shaft 11 is the distance ro_Ab of each of the plurality of second blades 12B. It is equal to the distance ro_Bb between the outer peripheral end 15B and the rotating shaft 11. In the first cross section, each outlet angle βbo_Ab of the plurality of first wings 12A is equal to each exit angle βbo_Bb of the plurality of second wings 12B.

According to this configuration, the direction of the airflow flowing out from the impeller 10 can be made uniform regardless of the circumferential position of the impeller 10. If the direction of the airflow flowing out of the impeller 10 varies depending on the circumferential position of the impeller 10, noise such as rotation noise is generated. Therefore, according to the above configuration, noise such as rotating noise can be suppressed.

In the above embodiment, a multi-blade blower provided with a single-suction impeller 10 in which a plurality of blades 12 are formed only on one side of the main plate 13 is given as an example, but the present invention has described both sides of the main plate 13. It can also be applied to a multi-blade blower equipped with a double-suction impeller with multiple blades formed on each.

10 impeller, 11 rotating shaft, 12 wings, 12A 1st wing, 12A1 outer peripheral wing, 12A2 inner peripheral wing, 12B 2nd wing, 13 main plate, 14A, 14B inner peripheral end, 15A, 15B outer peripheral end, 20, 21 string wire, 22, 23 warp wire, 30 casing, 31 scroll wall, 32 suction port, 33 outlet, 40 drive motor, 41 motor shaft, 51 first plane, 52 second plane, C1 circle.

Claims (6)

A multi-blade blower equipped with an impeller that rotates around a rotating shaft.
The impeller has a plurality of blades arranged in a circumferential direction about the rotation axis, and a main plate that supports the plurality of blades from one side in a direction along the rotation axis.
In the first cross section of the impeller cut in the first plane perpendicular to the rotation axis, each of the plurality of blades is provided on the inner peripheral end and the outer peripheral side of the inner peripheral end, and the impeller is provided. Has an outer peripheral edge that is inclined forward in the direction of rotation of
The plurality of wings have a plurality of first wings and a plurality of second wings.
In the first cross section, each of the plurality of first wings has a wingspan longer than the wingspan of each of the plurality of second wings.
In the first cross section, the distance between the rotating shaft and the inner peripheral end of each of the plurality of first wings is larger than the distance between the rotating shaft and the inner peripheral end of each of the plurality of second wings. It's getting shorter
At least one second wing of the plurality of second wing is arranged between the two first wing adjacent to each other in the circumferential direction among the plurality of first wing.
Each of the plurality of first wings
A first portion composed of a part closer to the main plate in the direction along the rotation axis and formed so that the wingspan becomes longer as it approaches the main plate.
It consists portions other than the first portion, possess a second portion blade length is formed so as to be constant,
The length of the first portion in the direction along the rotation axis is shorter than the length of the second portion in the direction along the rotation axis.
The entire main plate is composed of a plane perpendicular to the rotation axis.
Multi-wing blower. In the first cross section, each of the plurality of first wings has an outer peripheral wing portion located on the outer peripheral side of the circle in contact with the inner peripheral end of each of the plurality of second wings about the rotation axis. It has an inner peripheral wing located on the inner peripheral side of the circle.
The first portion of each of the plurality of first wings includes the outer peripheral side wing portion and the inner peripheral side wing portion.
The second portion of each of the plurality of first wings includes the outer peripheral wing portion.
In each of the outer peripheral side wing portion and the inner peripheral side wing portion, the ratio of the warp height to the chord length is defined as the warp ratio, the warp height in the direction opposite to the rotation direction is represented by a positive value, and the warp height in the rotation direction is expressed as a positive value. When the warp height is expressed as a negative value,
The multi-blade blower according to claim 1, wherein the warp ratio of the outer peripheral side blade portion is larger than the warp ratio of the inner peripheral side blade portion. When the plane perpendicular to the axis of rotation and the distance from the main plate is longer than the distance between the first plane and the main plate is defined as the second plane.
The distance between the rotating shaft in the second cross section of the impeller cut in the second plane and the inner peripheral end of each of the plurality of first blades is the distance between the rotating shaft in the first cross section and the plurality. The multi-blade blower according to claim 1 or 2, which is longer than the distance of each of the first blades from the inner peripheral end. When viewed in parallel with the rotation axis, each of the plurality of blades in the second cross section does not protrude from the contours of the plurality of blades in the first cross section. The multi-blade blower according to claim 3, which overlaps with each of the above. In the first cross section, the distance between the outer peripheral end of each of the plurality of first wings and the rotating shaft is equal to the distance between the outer peripheral end of each of the plurality of second wings and the rotating shaft.
The multi-blade blower according to any one of claims 1 to 4, wherein in the first cross section, the outlet angle of each of the plurality of first blades is equal to the outlet angle of each of the plurality of second blades. .. In the third cross section of the impeller cut at the center of each of the plurality of first blades and the plurality of second blades in the direction along the rotation axis, the said one of the plurality of first blades. The multiple according to any one of claims 1 to 5, wherein the distance between the inner peripheral end and the rotating shaft is equal to the distance between the inner peripheral end of each of the plurality of second blades and the rotating shaft. Wing blower.

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