JP2002155895A - Impeller of multiblade blower and multiblade blower provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a impeller capable of improving efficiency of a multiblade blower and reducing noise. SOLUTION: The impeller 13a of the multiblade blower comprises a main shroud 34, a plurality of blades 33 and 36, and a side shroud 32. The plural blades 33 and 36 are annularly arranged around a rotation axis, and one end of each of the blades is fixed to the main shroud 34. The other ends of the plural blades 33 and 36 are connected to one another by the annular side shroud 32. In the improved blades 36, an angle formed by a front face in a rotating direction at inner peripheral side and a front face in a rotating direction at an outer peripheral side is set smaller at the other end (side shroud 32 side) than a vicinity of one end (main shroud 34 side). Further, a chord length of each of the improved blades 36 is longer at the vicinity of the other end (side shroud 32 side) than the vicinity of the one end (main shroud 34 side).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller of a multi-blade blower and a multi-blade blower provided with the impeller, and more particularly to a multi-blade blower having ends of a plurality of blades extending from a main plate connected by an annular side plate.

[0002]

2. Description of the Related Art In an air conditioner (hereinafter, referred to as an air conditioner) such as an air purifier or an air conditioner, a multi-blade blower is used to blow air. 1 to 3 show an example of a multi-blade fan called a sirocco fan. The sirocco fan shown here is a blower provided with a large number of blades that are short in the radial direction and long in the axial direction.

The sirocco fan 10 comprises an impeller 13, a casing 11 for covering the impeller 13, a motor 14 for rotating the impeller 13, and the like. The impeller 13 has one end of a number of blades 33 fixed to the outer peripheral edge of a disk-shaped main plate 31,
The other ends of the wings 33 are connected by a ring-shaped side plate 32. The casing 11 has an air outlet 11a.
And the air inlet 1 surrounded by the bell mouth 12
1b are formed. The suction port 11 b faces the side plate 32 of the impeller 13. In addition, the outlet 11
a is formed so as to blow air in a direction substantially orthogonal to the rotation axis O of the impeller 13 and to be orthogonal to the suction port 11b.

When the sirocco fan 10 is operated by turning the motor 14, the impeller 13 rotates in the rotation direction R in FIG. This allows
Each wing 33 of the impeller 13 sweeps out air from the inner space to the outer space, and the impeller 13
The air is sucked into the space on the inner peripheral side of the impeller 13 and the air pushed out to the outer peripheral side of the impeller 13 is blown out through the outlet 11a. That is, the sirocco fan 10
Sucks air from the suction port 11b and sends out air from the blowing port 11a.

[0005]

The above-mentioned conventional multi-blade fan (sirocco fan) is often used when a low wind pressure blower is required, and has the advantages of being small and low in noise. I have.

However, multi-blade fans are required to have lower noise and higher efficiency. An object of the present invention is to provide an impeller in which the efficiency of a multi-blade fan is improved and noise is reduced, and to provide a high-efficiency, low-noise multi-blade fan.

[0007]

According to a first aspect of the present invention, an impeller for a multi-blade blower includes a main plate, a plurality of blades, and side plates. The main plate rotates about a rotation axis. The plurality of wings are arranged annularly around the rotation axis, and one ends of the wings are fixed to the main plate. The side plate is annular and connects the other ends of the plurality of wings. Also, at least one of the wings has an angle formed by the front surface in the rotation direction on the inner peripheral side near the rotation axis and the front surface in the rotation direction on the outer peripheral side far from the rotation axis, the other end (side plate) closer to the one end (main plate side). Side) is smaller.

In the conventional impeller of a multi-blade blower, as shown in FIGS. 2 and 3, the cross-sectional shape of the blades 33 hardly changes on the main plate 31 side or the side plate 32 side. That is, the wing 33
It extends substantially straight from the main plate 31 toward the side plate 32. In recent multi-blade blowers, especially medium-sized and small multi-blade blowers used for air conditioners, most of the impellers are made of resin. Wings 33 from the main plate 31 to the side plate 32
In some cases, a taper (draft) is provided so that the cross section of the mold becomes slightly smaller, so that the mold is easily removed after molding.

However, when the present inventor examined the air flow in the multi-blade fan in order to improve the blowing efficiency of the multi-blade fan, it was found that the blade 33 had a substantially uniform cross-sectional shape. It was found that the contribution of the wing 33 to the airflow near the side plate 32 was low. That is, inside the sirocco fan 10, the air flow W is as shown in FIG. 1A, and a portion of the length L1 of the blade 33 that mainly contributes to the air flow W is shown in FIG.
Has been found to be limited to the length L2 shown in FIG. This means that the blade 3 near the outer peripheral end of the impeller 13
This is supported by measuring the wind speed at a plurality of locations in the length direction of the three. As described above, in the conventional multi-blade blower, the blades do not work effectively over the entire length, and a part of the side plate side does not function sufficiently, so that it is difficult to improve the blowing efficiency and noise. I understood.

Therefore, in the impeller of the multi-blade blower according to the first aspect, at least one blade (hereinafter referred to as “improved”) is used in order to effectively use the entire length of the blade to improve the blowing efficiency and reduce noise of the multi-blade blower. Wing), the angle formed by the rotation-direction front surface on the inner peripheral side near the rotation axis and the rotation-direction front surface on the outer peripheral side far from the rotation axis is closer to the other end (side plate side) than near the one end (main plate side). It was made smaller in the vicinity. By doing so, the amount of air that is swept from the inner peripheral side to the outer peripheral side of the portion near the other end of the wing increases, and the wing approaches a state in which the wing works effectively over the entire length. As a result, the blowing efficiency of the entire multi-blade blower is improved, and noise is reduced.

It is to be noted that all of the plurality of blades may be improved blades, or only one blade or one out of several blades may be improved blades. By adopting such an improved blade, it is desirable that the wind speed distribution in the vicinity of the outer peripheral end of the impeller becomes substantially uniform as a whole in the blade length direction (rotation axis direction).

The impeller of the multi-blade blower according to claim 2 is the impeller of the multi-blade blower according to claim 1, wherein at least one of the blades (improved blade) has a chord length of: It is longer near the other end than near the one end.

In this case, in order to effectively use the entire length of the blade to improve the blowing efficiency of the multi-blade blower and to realize low noise, the chord length of the improved blade is greater than that near the one end (main plate side). (The side plate side) was made longer in the vicinity. By doing so, the amount of air that is swept from the inner peripheral side to the outer peripheral side of the portion near the other end of the wing increases, and the wing approaches a state in which the wing works effectively over the entire length. This allows
The blowing efficiency of the multi-blade fan as a whole is improved, and the noise is reduced.

According to a third aspect of the present invention, there is provided an impeller for a multi-blade blower according to the first or second aspect, wherein the plurality of blades extend from the main plate to the side plate without twist. The impeller of the multi-blade blower according to claim 4 is the impeller of the multi-blade blower according to any one of claims 1 to 3, which is formed by integrally molding a resin by using a plurality of molds. It is. The main plate has an opening for removing a part of the mold.

In the impeller of the multi-blade blower according to any one of the first to third aspects, the angle formed by the inner peripheral front surface and the outer peripheral front surface is smaller near the other end than near the one end. By adopting improved wings and improved wings whose chord length is longer near the other end than near one end, the blowing efficiency of the multi-blade blower is improved and noise is reduced.

However, in recent multi-blade blowers, particularly in a medium-sized or small-sized multi-blade blower used for an air conditioner, most of the impellers are made of resin. In the case where the impeller is integrally formed of resin, a taper (draft) in which the chord length and the cross section of the blade become slightly smaller from the main plate toward the side plate is provided, and the die after molding is removed. There are many ways to improve it. That is, it is extremely difficult to integrally mold the impeller including the above-mentioned improved blade with resin.

Therefore, in the impeller of the multi-blade blower according to the present invention, an opening for removing a part of the mold is provided in the main plate so that the impeller can be integrally formed of resin even when the improved blade is present. I have. That is, for example, when there is a first type that hits the main plate from the outside and a second type that hits the side plate from the outside,
Instead of using only the second mold to form the improved wing, it is possible to form a part of the improved wing by inserting a part of the first mold into the side plate side of the main plate through the opening. In this way, even with the improved wing as described above, the mold can be removed by performing integral molding with resin.

The impeller of the multi-blade blower according to claim 5 is the impeller of the multi-blade blower according to any one of claims 1 to 3, and is made of resin. The main plate is provided with an opening corresponding to at least one of the wings (improved wing).

Here, an opening corresponding to the improved wing is provided in the main plate. For this reason, even if there is an improved blade, it is possible to integrally mold the impeller with resin. That is, for example, when there is a first mold that contacts the main plate from the outside and a second mold that contacts the side plate from the outside, the improved wing is not formed only by the second mold, but is formed by the first mold through the opening. The part can be inserted into the side plate side of the main plate to form a part of the improved wing. With this configuration, even with the improved blade in the impeller of the multi-blade blower according to any one of claims 1 to 3, the mold can be removed by performing integral molding with resin.

A multi-blade blower according to a sixth aspect includes the impeller according to any one of the first to fifth aspects, a driving means, and a casing. The driving means rotates the main plate.
The casing covers the impeller, and has a suction port and a discharge port. The suction port faces the opening on the inner peripheral side of the side plate. The outlet is provided on the outer peripheral side of the impeller, and sends out gas in a direction substantially orthogonal to the rotation axis.

Here, when the driving means rotates the main plate, the impeller rotates with respect to the casing. Then, each blade of the impeller raked out air from the space on the inner peripheral side to the space on the outer peripheral side, air was sucked into the space on the inner peripheral side of the impeller from the suction port, and was pushed out to the outer peripheral side of the impeller. Air is pumped through the outlet. That is, the multi-blade blower sucks air from the suction port and sends out air from the blowing port.

At this time, since the suction port and the discharge port are arranged so as to be substantially orthogonal to each other, air from the suction port easily flows near one end of the blade (on the side of the main plate). It becomes difficult to flow near the (side plate side). In this case, variations occur in the wind speed distribution on the outer peripheral side of the impeller, which causes a reduction in efficiency of the multi-blade blower and an increase in noise, so that the blade according to any one of claims 1 to 5 is used here. A car is used to increase the amount of air scraped from the inner peripheral side to the outer peripheral side near the other end (side plate side) of the wing. As a result, the blade approaches a state in which it works effectively over the entire length, and the blowing efficiency as a multi-blade blower is improved, and noise is reduced.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sirocco fan (multi-blade blower) according to an embodiment of the present invention is the same as the sirocco fan 10 shown in FIGS. The improved wing 36 shown in FIG. 5, FIG. 6 (b) and FIG.
In order to form an improved wing 36.
This adopts a main plate 34 having b. This sirocco fan 10a is shown in FIG.

<Structure of Sirocco Fan 10a> The sirocco fan 10a mainly includes an impeller 13a and an impeller 1
It is composed of a casing 11 that covers 3a and a motor 14 that rotates an impeller 13a.

The impeller 13a has a plurality of blades 33 and one end of an improved blade 36 fixed to the outer peripheral edge of a disk-shaped main plate 34.
The other ends of the wings 33 and the improved wings 36 are connected by a ring-shaped side plate 32. Details of the impeller 13a will be described later.

The casing 11 has an air outlet 1
1a and an air inlet 11b surrounded by a bell mouth 12 are formed. Suction port 11b
Are arranged to face the side plate 32 of the impeller 13a. The air flowing through the suction port 11b into the space at the inner peripheral portion of the impeller 13a flows substantially along the rotation axis O of the impeller 13a, and moves away from the rotation axis O by the rotation of the impeller 13a ( (The outer circumferential direction of the impeller 13a). The outlet 11a is provided with an impeller 13a.
It is formed so as to blow out air in a direction substantially perpendicular to the rotation axis O, and perpendicular to the suction port 11b.

The motor 14 has a rotary shaft whose main plate 3
4 is mounted in the center hole 34a (see FIG. 5), and by rotating the main plate 34, the entire impeller 13a is rotated. The main body of the motor 14 is fixed to the casing 11.

<Operation of Sirocco Fan 10a> Motor 1
When the sirocco fan 10a is operated by turning 4, the impeller 13a rotates in the rotation direction R shown in FIGS. 5 and 7 with respect to the casing. That is, in the sirocco fan 10a, air is mainly scraped off by the concave front surface of the blades 33 and 36 in the rotation direction R. As a result, the blades 33 and 36 of the impeller 13a sweep out air from the space on the inner circumference side of the impeller 13a to the space on the outer circumference side, and the air is sucked into the space on the inner circumference side of the impeller 13a from the suction port 11b. At the same time, the air scraped to the outer peripheral side of the impeller 13a is collected at the outlet 11a and is blown out (see the air flow W in FIG. 4). That is, the sirocco fan 10a sucks air from the suction port 11b along the rotation axis O, and sends out the air from the blowing port 11a in a direction orthogonal to the rotation axis O. Although only the air flow W on the right side of the rotation axis O is shown in FIG. 4, the air scraped to the outer peripheral side of the impeller 13a on the left side of the rotation axis O
It flows to and is blown out from there.

<Detailed Configuration of Impeller 13a> Impeller 13a
As shown in FIGS. 4 and 5, the main plate 34, the plurality of blades 33, the plurality of improved blades 36, and the ring-shaped side plate 32
It is composed of The impeller 13a is a resin product integrally formed using a mold as described later.

[Main Plate 34] The main plate 34 has a disc shape, and has a center hole 34a and a plurality of die-cut holes 34b as shown in FIG. The rotating shaft of the motor 14 is fixed to the center hole 34a. Die release hole 34b
Are provided for the number of improved wings 36 described later.
As shown in FIG. 5, it is arranged so as to overlap a second portion 36b (described later) of the improved wing 36 in plan view. That is, the punching holes 34b are provided corresponding to the respective improved blades 36.

[Wings 33, 36] Wings 33 and improved wings 36
Are arranged annularly around the rotation axis O, one end of which is fixed to the outer peripheral edge of the main plate 34, and extend therefrom along the rotation axis O without twisting. The other ends of the wing 33 and the improved wing 36 are connected by a ring-shaped side plate 32 as shown in FIGS. The number of wings 33 is twice the number of improved wings 36. The improved wings 36 are arranged at equal intervals in the circumferential direction. Further, the wings 33 are each improved wing 3
The two blades are arranged between the six blades so that the gaps between adjacent blades 33 or improved blades 36 are equal.

The shape of the wing 33 is the same as that of the conventional wing.
As shown in FIG. 6, the wing 33 has a shape in which the chord length C1 at one end connected to the main plate 34 is slightly smaller than the chord length C2 at the other end connected to the side plate 32. Therefore, when forming the wing 33, 1
The wing 33 is covered with the two dies, and the dies can be pulled out to the left side in FIG. 6A. Further, as shown in FIG. 7, the cross-sectional shape of the wing 33 may be at one end connected to the main plate 34.
The other end connected to the side plate 32 has substantially the same shape.

[Improved wing 36] On the other hand, the shape of the improved wing 36 is mainly in the vicinity of the other end connected to the side plate 32,
The blade 33 has a shape protruding in an inner circumferential direction (a direction toward the rotation axis O). As shown in FIG. 6B, the improved wing 36 has a shape such that a chord length C1 at one end connected to the main plate 34 is larger than a chord length C3 at the other end connected to the side plate 32. is there. Therefore,
The improved blade 36 has a first portion 36a extending along the rotation axis O from a blade cross section at one end, and a second portion 36b protruding inward from the first portion 36a.

The other end of the improved blade 36 connected to the side plate 32 has an angle formed between the front surface in the rotation direction near the rotation axis O and the front surface in the rotation direction far from the rotation axis O at the other end. The angle is θ2 (see FIG. 7). On the other hand, at one end of the improved wing 36 connected to the main plate 34,
The angle formed between the inner circumferential side front surface in the rotational direction and the outer circumferential side front surface in the rotational direction is an angle θ1. This angle θ1 is
The angle θ1 is equal to the angle θ1 (see FIG. 7) formed by the inner circumferential front surface and the outer circumferential front surface at one end of the third end 3. That is, the cross-sectional shape at one end of the wing 33 and the cross-sectional shape at one end of the improved wing 36 are substantially the same. And the angle θ2
Is smaller than the angle θ1 (see FIG. 7), and the angle formed between the inner circumferential side front surface and the outer circumferential side front surface in the cross section of the improved wing 36 is near the one end connected to the main plate 34. It is smaller near the other end connected to the side plate 32 than it is.

The improved wing 36 is also connected to the side plate 32 from the main plate 34.
7, the cross section at one end (on the side of the main plate 34) of the improved wing 36 is within the cross section at the other end (on the side of the side plate 32), as shown in FIG.

[Side plate 32] The ring-shaped side plate 32 is
3 and the other end of the improved wing 36 are arranged on the outer peripheral side, and are connected to the respective wings 33 and the improved wing 36. That is, the side plate 32 connects the respective wings 33 and the improved wings 36. The side plate 32 is also integrally formed with the main plate 34, the wing 33, and the improved wing 36.

<Molding of Impeller 13a> The impeller 13a having the above-described configuration is formed by integrally molding resin using two molds 51 and 52.

In the molds 51 and 52, a portion for forming the improved wing 36 has a shape as shown in FIG. As shown in FIG. 9, when the molds 51 and 52 are brought together, the improved wing forming part 52a of the mold 52 forms the first portion 36a of the improved wing 36, and the improved wing forming part 51a of the mold 51 is improved by the improved wing. The second part 36b of 36 is formed.

With these dies 51, 52, the impeller 1
When the mold 3a is formed, the two dies 51, 52 shown in FIG. 9 are pulled out on both sides. At this time, the improved wing forming portion 51a of the dies 51 is formed with the die-cut holes 34b of the main plate 34 of the impeller 13a.
Will be removed from

<Features of Sirocco Fan 10a> (1) When the motor 14 rotates the main plate 34, the impeller 13a rotates with respect to the casing 11. Then, each blade 33, 36 of the impeller 13a sweeps out air from the space on the inner peripheral side of the impeller 13a to the space on the outer peripheral side of the impeller 13a, and from the suction port 11b to the space on the inner peripheral side of the impeller 13a. The air is sucked in, and the air pushed to the outer peripheral side of the impeller 13a passes through the outlet 11a, and the sirocco fan 1
It is sent out of 0a. That is, the sirocco fan 10a sucks air from the suction port 11b and sends out air from the blowing port 11a.

At this time, since the suction port 11b and the blowout port 11a are arranged so as to be substantially orthogonal to each other, the air from the suction port 11b flows near one end (the main plate 34 side) of the blades 33, 36. It ’s easy, but the wings 33, 36
Flow near the other end (side plate 32 side).

On the other hand, in the sirocco fan 10a, several improved blades 36 are employed to increase the amount of air scraped from the inner space to the outer space in the vicinity of the suction port 11b. I have.

More specifically, the improved blade 36 is attached to the side plate 32 with respect to the chord length C1 at one end connected to the main plate 34.
The shape is such that the chord length C3 at the other end connected thereto is large. In addition, the angle formed between the inner circumferential rotation front face and the outer circumference rotation direction front face in the cross section of the improved wing 36 is more connected to the side plate 32 than near the one end connected to the main plate 34 (angle θ1). It is smaller near the end (angle θ2) (angle θ2 <angle θ
1). By using the improved wing 36 having such a shape in addition to the wing 33, air is swept from the inner circumference to the outer circumference of the impeller 13a even near the suction port 11b, and the rotation of the impeller 13a on the outer circumference is performed. The wind speed distribution along the axis O approaches evenly.

For this reason, even if the output of the motor 14 is the same, the amount of air blown out from the blowout port 11a of the sirocco fan 10a increases as compared with a conventional multiblade blower that does not use the improved blade 36. Noise is reduced. That is, the blowing efficiency as a multi-blade blower is improved, and noise is reduced.

(2) Here, the impeller 13a is made of resin.
Wing forming part 51a of the mold 51
The main plate 34 is provided with a mold release hole 34b for removing the mold.
This enables the impeller 13a to be integrally molded with the resin using the improved blades 36.

By providing the punching holes 34b in the main plate 34 in this manner, the improved wings 36 are not formed only by the die 52, but the die 51 is formed through the punching holes 34b.
With the improved wing forming portion 51a inserted into the side plate 32 side of the main plate 34, a part of the improved wing 36 (second portion 36b) can also be formed by the mold 51.

<Modifications> (1) In the above embodiment, the present invention is applied to the sirocco fan 10a using the resin impeller 13a. However, the present invention is applied to a multi-blade blower using a sheet metal impeller. The present invention can also be applied to such cases. Also, not only for sirocco fans,
The present invention can be applied to other multi-blade blowers.

(2) In the above embodiment, the number of the improved wings 36 is set to half of the number of the wings 33 in consideration of the pitch between the wings 33 and 36 and the strength of the main plate 34. It is also possible to increase the number, to make all the wings the shape of the improved wings 36, or to reduce the number of the improved wings 36.

The number and shape of the improved blades 36 are desirably determined so that the wind speed distribution near the outer peripheral end of the impeller 13a is substantially uniform in the direction of the rotation axis O as a whole of the impeller 13a.

(3) In the above embodiment, the present invention is applied to the so-called one-suction type sirocco fan 10a. However, even in the double-suction type multi-blade blower, the suction side of the impeller from the inner side of the impeller. The effect of the present invention can be obtained by employing an improved wing that increases the amount of air scraped to the outer peripheral side.

(4) In the above embodiment, the chord length C3 at the other end is larger than the chord length C1 at the one end, and the angle formed by the inner circumferential side front surface in the rotational direction and the outer circumferential side front surface in the rotational direction is larger. Although the improved blade 36 that is smaller in the vicinity of the other end than in the vicinity of one end is employed, even when an improved blade that satisfies only one of the conditions is used, a multi-blade fan is As a result, the blowing efficiency is improved and the noise is reduced.

[0052]

According to the first aspect of the present invention, at least 1
For one wing (improved wing), the angle formed between the inner circumferential front side and the outer circumferential front side becomes smaller near the other end (side plate side) than near one end (main plate side). I did it. Therefore, the amount of air scraped from the inner peripheral side to the outer peripheral side in the vicinity of the other end of the blade increases, and the distribution of the wind velocity at the exit of the impeller approaches evenly. Is also smaller.

In the invention according to claim 2, the chord length of the improved blade is made longer near the other end (side plate side) than near one end (main plate side). Therefore, the amount of air scraped from the inner peripheral side to the outer peripheral side in the vicinity of the other end of the blade increases, and the distribution of the wind velocity at the exit of the impeller approaches evenly. Is also smaller.

According to the third aspect of the present invention, the improved blade is employed for a multi-blade blower of a type in which a plurality of blades extend from the main plate to the side plate without twisting, and the above-described effects can be obtained. In the invention according to claim 4, since the opening for removing a part of the mold is provided in the main plate, even when the wing according to any one of claims 1 to 3 is provided, integral molding with resin becomes easy.

According to the fifth aspect of the present invention, since the main plate is provided with an opening corresponding to at least one of the wings according to any one of the first to third aspects, a resin impeller is integrally molded. Can be easily removed.

According to the invention of claim 6, in claims 1 to 5,
And the amount of air scraped from the inner peripheral side to the outer peripheral side near the other end (side plate side) of the blade is increased, so that the blowing efficiency as a multi-blade blower is increased. And noise is reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a conventional multi-blade blower (a casing is a sectional view).

FIG. 2 is a perspective view of a conventional impeller.

FIG. 3 is a front view of a conventional impeller.

FIG. 4 is a side view (a sectional view of a casing portion) of the multi-blade blower according to the embodiment of the present invention.

FIG. 5 is a front view of the impeller.

FIG. 6 (a) is a side view of a wing (a main plate and side plate portions are sectional views). (B) A side view of the improved wing (a main plate and side plate portions are sectional views).

FIG. 7 is a partially enlarged view of FIG. 5;

FIG. 8 is a view showing a shape of a part of a mold.

FIG. 9 is a diagram showing molding of an improved wing by a mold.

[Explanation of symbols]

 Reference Signs List 10a Multi-blade blower 11 Casing 11a Blow-out port 11b Suction port 13a Impeller 14 Motor (drive means) 32 Side plate 33 Blade 34 Main plate 34b Drilled hole (opening) 36 Improved blade (at least one of blades) 51, 52 Mold 51a Improved wing formation part O Rotation axis R Rotation direction C1, C2, C3 Chord length

Claims (6)

[Claims] 1. A main plate (34) rotating about a rotation axis (O), and a plurality of annularly arranged around the rotation axis (O), one ends of which are fixed to the main plate (34). A wing (33, 36); and an annular side plate (32) connecting the other ends of the plurality of wings (33, 36), wherein at least one of the wings (36) is the rotation axis (O).
The angle formed between the front side in the rotation direction on the inner peripheral side near to and the front side in the outer peripheral direction far from the rotation axis (O) is smaller in the vicinity of the one end than in the vicinity of the one end. Impeller (13a) of a wing blower. 2. A multi-blade blower according to claim 1, wherein at least one of the wings has a chord longer near the other end than near the one end. Impeller (13a). 3. An impeller (13) for a multi-blade blower according to claim 1, wherein said plurality of blades (33, 36) extend without twist from said main plate (34) to said side plate (32).
a). 4. An opening for removing a part (51a) of the mold from the main plate (34), the resin being formed integrally by using a plurality of molds (51, 52). 4. The method according to claim 1, wherein (34b) is provided.
An impeller (13a) for a multi-blade blower according to any one of the above. 5. The resin-made multi-layer structure according to claim 1, wherein said main plate (34) is provided with an opening (34b) corresponding to at least one of said wings (36). Impeller (13a) of a wing blower. 6. An impeller (13a) according to any one of claims 1 to 5, a driving means (14) for rotating said main plate (34), and a suction opposed to an inner peripheral opening of said side plate. Mouth (11
b) and an outlet (11a) which is provided on the outer peripheral side of the impeller (13a) and sends out gas in a direction substantially perpendicular to the rotation axis (O), and covers the impeller (13a). And a casing (11).
a).