WO2003002874A1

WO2003002874A1 - Impeller for multiblade blower, and multiblade blower having the same

Info

Publication number: WO2003002874A1
Application number: PCT/JP2002/005883
Authority: WO
Inventors: Masahito Higashida
Original assignee: Daikin Industries, Ltd.
Priority date: 2001-06-28
Filing date: 2002-06-12
Publication date: 2003-01-09
Also published as: EP1411247A1; DE60229060D1; EP1411247B1; CN1212478C; ES2312576T3; ATE409287T1; CN2572074Y; EP1411247A4; CN1395046A

Abstract

The invention provides an impeller capable of reducing the noise due to turbulence vortexes produced in the vicinity of the main plate of the impeller, and provides a low-noise multiblade blower. A multiblade blower (40) consists mainly of an impeller (43), a casing (11) covering the impeller (43), and a motor (14) for rotating the impeller (43). The impeller (43) comprises a plurality of blades (33) fixed in the outer peripheral edge of a main plate (61) in the form of a circular plate, the blades (33) being connected together at their other ends by an annular side plate (62). Interblade portions (65) between the blades (33) on the main plate (61) are cut at their front portions as seen in the direction of rotation. These interblade portions (65) are greater than the circumferential thickness of the blades (33) and are cut to such a length that they do not reach the rear of the other blades (33) that are adjacent the front as seen in the direction of rotation. Further, the radial portions of the interblade portions (65) are cut along the shape of the blades (33) to a length extending from the outer peripheral edge to the inner peripheral edge.

Description

Description Multi-blade impeller impeller and multi-blade blower provided with the impeller

The present invention relates to an impeller of a multi-blade fan and a multi-blade fan including the same, and more particularly, to an impeller of a multi-blade fan having ends of a plurality of blades extending from a main plate connected by an annular side plate, and a multi-blade including the same. It relates to a wing blower. Background art

2. Description of the Related Art In air conditioners such as gas purifiers and air conditioners (hereinafter referred to as air conditioners), multi-blade blowers are used to blow air. Figures 1 to 3 show a conventional multi-blade blower. Here, FIG. 1 shows a side view of a conventional multi-blade fan, FIG. 2 shows a perspective view of an impeller of the conventional multi-blade fan, and FIG. 3 shows a blade of the conventional multi-blade fan. FIG. 2 shows a plan view of the car.

The multi-blade blower 10 includes an impeller 13, a casing 11 for covering the impeller 13, a motor 14 for rotating the impeller 13, and the like. In the impeller 13, one end of a number of blades 33 is fixed to an outer peripheral edge of a disk-shaped main plate 31, and the other ends of the blades 33 are connected by an annular side plate 32. The casing 11 has a gas outlet 11 a and a gas inlet 11 b surrounded by a bell mouth 12. The suction port 11b faces the side plate 32 of the impeller 13. The outlet 11a is formed in a direction perpendicular to the inlet 11b so as to blow out gas in a direction substantially perpendicular to the rotation axis 0-0 of the impeller 13.

When the motor 14 is rotated to operate the multi-blade blower 10, the impeller 13 rotates in the rotation direction R of FIG. 3 with respect to the casing 11. As a result, each blade 33 of the impeller 13 pumps out gas from the space on the inner circumference side to the space on the outer circumference side, and gas flows from the suction port 11 b into the space on the inner circumference side of the impeller 13. While being sucked, the gas pushed to the outer peripheral side of the impeller 13 is sent out through the outlet 11a. That is, the multi-blade blower 10 sucks gas from the inlet 11b and sends gas from the outlet 11a. I do.

In such a multi-blade blower 10, there is noise due to turbulent vortices generated near the main plate 31. Specifically, it is caused by the following generation mechanism. Inside the impeller 13, the gas sucked from the inlet 11 b flows mainly from the direction toward the main plate 31 toward the outer periphery gradually as shown in FIG. 1 (a). Yes (see gas flow W). By the way, as shown in Fig. 1 (b), a part of the gas sucked from the suction port 11b flows toward the outer periphery after colliding with the main plate 31 near the main plate 31. Yes (see gas flow X). In this gas flow X, a turbulent vortex is generated due to collision with the main plate 31. The turbulent vortex develops gradually as the gas flow X moves toward the outer periphery and the flow colliding with the main plate 31 further merges. Form a vortex. The developed turbulent vortex is ejected toward the outer peripheral side by the wings 33 to generate noise.

Also, in the blower as described above, if reduction of manufacturing cost is important, the cross-sectional shape of the wing is almost the same at each position so that the pair of upper and lower dies can be integrally molded from a resin material. It is designed to be. In other words, the wings with inclined wings are not bent so that they can be formed only by the upper and lower dies (see wing 33 in Figs. 2 and 3). However, such a wing shape creates a condition in which the amount of inflow and outflow of air is different at each position of the wing, which contributes to noise generation.

As a measure to reduce such noise, it is effective to take measures such as tilting the wing at an appropriate position, but by doing so, the wing shape cannot be integrally formed with only the upper and lower dies. And the cost of producing the impeller is greatly increased. In other words, a resin molding operation using a slide is required to form the inclined part of the wing, which increases the manufacturing cost by increasing the number of dies and increases the molding time. Disclosure of the invention

An object of the present invention is to reduce noise caused by turbulent vortices generated near the main plate of an impeller. It is an object of the present invention to provide an efficient impeller and a low-noise multi-blade blower.

The impeller of the multi-blade blower according to claim 1, further comprising: a main plate that rotates around a rotation axis; and a plurality of blades that are annularly arranged around the rotation axis and each of which has one end fixed to the main plate. An annular side plate connecting the other ends of the plurality of wings. The interblade located between the plurality of wings of the main plate is notched at least forward in the rotation direction of the wing.

In the impeller of this multi-blade blower, the inter-blade located between the multiple blades of the main plate is notched at least forward in the rotational direction, so that the gas flow impinges on the main plate and the flow merges. A part of the developed turbulent vortex escapes from the space between the wings cut just before being ejected by the wings toward the outside of the main plate in the axial direction. As a result, noise generated when the gas flow is extracted by the wing can be reduced.

In the impeller for a multi-blade blower according to claim 2, the side plate has an inner diameter equal to or larger than the outer diameter of the main plate in claim 1. The inter-blade portion located between the wings of the main plate is notched larger than the outer dimensions of the wing.

Here, the notch between the blades of the main plate, which had not been cut off in the past, was cut out so that the wings of the other impeller were inserted between the wings of one impeller. So that two impellers can be overlapped. In the superposition, the side plate having an inner diameter equal to or larger than the outer diameter of the main plate does not become an obstacle, and the two impellers are superposed as long as the blades of the other impeller can pass through the cutout in the blade section of the main plate. Is done. Since a notch larger than the outer dimensions of the wing is formed in the space between the wings, the two impellers can be overlapped. As a result, the space efficiency during transportation is approximately doubled when two impellers are stacked, compared to the conventional method. If there is a large space between the blades and a notch that allows the two blades to pass through is formed in the space between the blades, it is possible to improve the space efficiency by about three times by overlapping three impellers.

The notch of the main plate between the blades seems to reduce the performance of the multi-blade blower on the other hand, so it has not been tried before. However, the inventor of the present application reviewed the impeller from various viewpoints, and the performance (efficiency and noise) of the blower was hardly reduced even if the notch was provided in the blade portion of the main plate as described above. Came to recognize. Based on this knowledge, the impeller according to the present invention has been created, and this impeller achieves both maintenance of the blowing capacity and improvement of transportability.

If there is no problem in strength and a slight decrease in performance can be tolerated, the option to cut out the entire wing between the wings instead of a part of the wing between the main plates and maximize space efficiency is selected. You can also.

In the impeller of the multi-blade blower according to claim 3, the inter-blade portion according to claim 1 or 2 is partially notched in a circumferential direction.

In the impeller of this multi-blade blower, the interblade portion is partially notched in the circumferential direction at least in front of the main plate in the rotation direction, and is not cut to the rear in the rotation direction of the interblade portion.

By the way, cutting out the rear part of the space between the blades in the rotational direction has the effect of releasing the turbulent vortex from the rear part in the rotational direction to the outside in the axial direction of the main plate together with the gas flow. Since it is the negative pressure surface of the wing, the gas flow becomes large. As a result, the gas flow may be separated, and the effect of noise reduction may be reduced. Therefore, in the impeller of this multi-blade fan, the gas flow does not increase because the rear portion in the rotational direction of the blade portion is not cut off. As a result, the effect of noise reduction due to the notch in the rotation direction of the space between the blades is not impaired.

In the impeller of the multi-blade blower according to claim 4, the inter-blade portion is cut off from the outer peripheral edge to the inner peripheral edge of the blade in any one of claims 1 to 3.

In the impeller of this multi-blade blower, the interblade is cut from the outer peripheral edge to the inner peripheral edge of the blade, so that the turbulent vortex is cut before reaching the outer peripheral edge of the blade. Easily escaped from the missing wings. As a result, the turbulent vortex reaching the outer peripheral edge of the blade is further reduced, and the noise can be reduced.

The multi-blade blower according to claim 5 is the multi-blade blower according to any one of claims 1 to 4, wherein each of the plurality of blades has an inclined portion that is inclined forward in the rotation direction. The inter-blade part is cut off at least by the projected partial force of the slope of each wing.

Here, the slopes are provided on the multiple blades, so that the difference in the amount of gas inflow and outflow at each position of the blades can be kept small, improving the ventilation efficiency and reducing noise. It will be easier. Also, besides providing an inclined part on each wing, Interference (main plate) is removed from the projected part of the slope of each wing. For this reason, the plurality of blades including the main plate can be integrally formed from the resin material using a pair of molds. In other words, the mold that enters through the notch (blade) of the main plate to form the inner surface of the inclined portion and the mold that forms the outer surface of the inclined portion from the opposite side allows the inclined portion that could not be integrally molded in the past. Wings can be formed. That is, with this blower, it is possible to obtain not only the effect of reducing noise but also the effect that resin integral molding becomes possible.

In the multi-blade blower according to claim 6, in claim 5, the plurality of blades are entirely inclined.

Here, the entire wing is inclined and the entire wing is inclined, so that the gas flow can be changed almost uniformly as a whole.

A multi-blade blower according to claim 7, an impeller according to any one of claims 1 to 6, a driving unit for rotating the main plate, a suction port and an impeller opposed to an inner peripheral opening of the side plate. And a casing which is provided on the outer peripheral side of the nozzle and has an air outlet for sending out gas in a direction substantially perpendicular to the rotation axis and which covers the impeller.

In this multi-blade blower, when the main plate is rotated by the driving means, the impeller rotates with respect to the casing. Then, each blade of the impeller blows out gas from the space on the inner circumference side to the space on the outer circumference side, and the gas pushed out from the suction port to the outer circumference side of the impeller is sent out through the outlet. That is, the multi-blade blower sucks gas from the inlet and sends out gas from the outlet.

At this time, since the impeller according to any one of claims 1 to 6 is employed, turbulent vortices generated by the collision of the gas flow with the main plate and the merge of the flows are generated from the interblade between the notched main plate. You can escape. This reduces turbulent vortices reaching the outer peripheral edge of the impeller, thereby reducing noise. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 (a) is a side view of a conventional multi-blade blower (the casing is a sectional view). FIG. 1 (b) is a side view of a conventional multi-blade blower, illustrating a noise generation mechanism in the vicinity of a main plate (partially showing a cross section of an impeller). FIG. 1 (c) is a side view of a conventional multi-blade fan, illustrating a noise generation mechanism near a side plate (a cross-section of a part of the impeller is shown).

FIG. 2 is a perspective view of an impeller of a conventional multi-blade fan.

FIG. 3 is a plan view of an impeller of a conventional multi-blade fan.

FIG. 4 is a side view of the multi-blade blower of the first embodiment (a casing is a sectional view). FIG. 5 is a side view (partially sectioned) of the impeller of the multi-blade fan of the first embodiment. FIG. 6 is a plan view of an impeller of the multi-blade blower according to the first embodiment.

Fig. 7 (a) is an enlarged view of the waveform shape (triangular wave shape).

Fig. 7 (b) is an enlarged view of the waveform (sinusoidal).

Fig. 7 (c) is an enlarged view of the waveform (rectangular waveform).

FIG. 8 (a) is a side view of the multi-blade blower of the first embodiment, illustrating a noise reduction effect of a corrugated shape formed on a main plate (a part of the cross section of the impeller is shown).

FIG. 8 (b) is a side view of the multi-blade blower of the first embodiment, illustrating the noise reduction effect of the corrugated shape formed on the side plate.

FIG. 8 (c) is a side view of the multi-blade blower of the first embodiment, illustrating a noise reduction effect of a shape in which the main plate is cut off between blades (a cross-sectional view of a part of the impeller is illustrated). ). FIG. 9 is a front view of an impeller according to a second embodiment of the present invention.

FIG. 10 (a) is a side view of the impeller of the second embodiment.

FIG. 10 (b) is a bb sectional view.

FIG. 11 (a) is a side view showing a state in which the impeller of the second embodiment is overlaid. Fig. 11 (b) is a side view showing a state in which conventional impellers are stacked.

FIG. 12 is a front view of an impeller according to a third embodiment of the present invention.

FIG. 13 (a) is a side view of the impeller of the third embodiment.

Fig. 13 (b) is a bb sectional view.

FIG. 14 is a top view of an impeller according to a fourth embodiment of the present invention.

Fig. 15 is a side view of the impeller.

FIG. 16 is a sectional view taken along the line VI-VI of FIG.

Fig. 17 is an enlarged view of part VII in Fig. 14.

FIG. 18 is a cross-sectional view taken along arrow VI 11 of FIG. FIG. 19 is a cross-sectional view of the mold in the cross section of FIG.

FIG. 20 is a longitudinal sectional view of a wing of a modified example (A) of the wing.

FIG. 21 is a longitudinal sectional view of a wing of a modified example (B) of the wing.

FIG. 22 is a longitudinal sectional view of a wing of a modified example (C) of the wing.

Fig. 23 is an enlarged top view of the wing of the modified example (D) of the wing.

FIG. 24 is an enlarged top view of another wing of the modified example (D) of the wing.

FIG. 25 is an enlarged top view of the wing of the modified example (E) of the wing. BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment]

(1) Configuration of multi-blade fan

A multi-blade blower (centrifugal blower) according to an embodiment of the present invention includes an impeller 13 of a conventional multi-blade blower 10 shown in FIGS. It has a corrugated shape in the vicinity of the edge, a corrugated shape on the side of the main plate 31 of the side plate 32, and a cutout at the front in the rotation direction of the plurality of interblades 35 of the main plate 31. The only difference is that it has a curved shape.

FIG. 4 shows a side view of the multi-blade blower 40 of the present embodiment, and FIGS. 5 and 6 show a side view and a plan view of the impeller 43 of the multi-blade blower 40.

The multi-blade blower 40 is mainly composed of an impeller 63, a casing 11 for covering the impeller 63, and a motor 14 for rotating the impeller 43.

The impeller 43 has a plurality of blades 33 fixed to an outer peripheral edge of a disk-shaped main plate 61, and the other ends of the plurality of blades 33 are connected by an annular side plate 62. Details of the impeller 43 will be described later.

The casing 11 has a gas outlet 11 a and a gas inlet 11 b surrounded by a bell mouth 12. The suction port 11b is arranged to face the side plate 62 of the impeller 43. The gas flowing through the suction port 1 1b into the space around the inner periphery of the impeller 4 3 generally flows along the rotation axis 0-0 of the impeller 43, and the rotation of the impeller 43 As a result, it flows in the direction away from the rotation axis 0-0 (in the outer circumferential direction of the impeller 43). In addition, the outlet 1 1a corresponds to the rotation axis 0-0 of the impeller 43. It is formed so as to blow out the gas in a direction substantially orthogonal to the suction port 11b.

The rotary shaft of the motor 14 is mounted in the center hole 61 a of the main plate 61 (see FIG. 6), and the entire impeller 43 is rotated by rotating the main plate 61. The main body of the motor 14 is fixed to the casing 11.

Next, the impeller 43 will be described.

The impeller 43 includes a main plate 61, a plurality of blades 33, and an annular side plate 62, as shown in FIGS. In the present embodiment, the impeller 43 is a resin product in which the main plate 61, the plurality of blades 33, and the side plates 62 are all integrally formed using a mold.

As shown in FIG. 6, the main plate 61 is a disc-shaped member having a center hole 61a formed therein, and the rotating shaft of the motor 14 is fixed to the center hole 61a.

On the outer peripheral edge of the main plate 61, a plurality of blades 33 described later are formed at equal intervals in the rotation direction, and near the inner peripheral edge of the plurality of blades 33, an inner peripheral edge is formed. An irregular corrugated shape 64 is formed along the periphery of. Here, the waveform shape 64 has a triangular wave shape, and has a wave pitch P of 3 mm and a wave height H of 2 mm (see FIG. 7 (a)). The waveform shape is not limited to a triangular wave shape, but may be a sine wave shape or a rectangular wave shape as shown in FIGS. 7 (b) and 7 (c). Also, the dimensions of the waveform shape are not limited to the dimensions of the present embodiment, and the pitch P is in the range of 2 mm or more and 8 mm or less, and the wave height H is 1 mm or more and 5 mm or less. It only has to be within the range.

In addition, the interblade portion 65 located between the plurality of wings 33 of the main plate 61 is notched forward in the rotation direction. These inter-blade portions 65 are circumferentially thicker than the circumferential thickness of the wing 33 and do not reach the rotational direction rearward of the other adjacent wings 33 in the rotational direction. Cut out in length. The radial direction of the interblade portion 65 is notched along the shape of the blade 33 so as to extend from the outer peripheral edge to the inner peripheral edge. The wing 33 is a member having a concave shape in the front in the rotation direction and arranged in a plurality of rings around the rotation axis 0-0. One end of the wing 33 is fixed to the outer peripheral edge of the main plate 61, and extends therefrom without any twist along the rotation axis 0-0. And the other end of wing 3 3 As shown in FIGS. 5 and 6, they are connected by an annular side plate 62.

The annular side plate 62 is arranged on the outer peripheral side of the other end of the wing 33, and connects the wings 33. The side plate 62 is also integrally formed with the main plate 61 and the plurality of blades 33. An uneven corrugated shape 66 is formed on the surface of the side plate 62 on the main plate 61 side. Here, the waveform shape 66 is, like the waveform shape 64 of the main plate 61, a triangular waveform having a wave pitch P of 3 mm and a wave height H of 2 mm (see FIG. 7 (a)). The waveform shape is not limited to a triangular wave shape, but may be a sine wave shape or a rectangular wave shape as shown in FIGS. 7 (b) and 7 (c). Also, the dimensions of the waveform shape are not limited to the dimensions of the present embodiment, and the pitch P is in the range of 2 mm or more and 8 mm or less, and the wave height H is in the range of 1 mm or more and 5 mm or less. Should be fine.

(2) Operation of multi-blade blower

When the motor 14 is turned to operate the multi-blade blower 40, the impeller 43 rotates in the direction of rotation R shown in FIG. 6 with respect to the casing 11. That is, in the multi-blade blower 40, air is mainly extracted by the concave surface of the blade 33 in the front in the rotation direction. As a result, the blades 3 3 of the impeller 4 3 discharge gas from the space on the inner peripheral side of the impeller 4 3 to the space on the outer peripheral side, and the inner peripheral side of the impeller 4 3 from the suction port 1 1 b. While the gas is sucked into the space, the gas discharged to the outer peripheral side of the impeller 43 is collected at the outlet 11a and blown out (see the gas flow Z in FIG. 4). That is, the multi-blade blower 40 sucks gas from the inlet 11b along the rotation axis 0-0, and sends out gas from the outlet 11a in a direction perpendicular to the rotation axis 0-0. In FIG. 4, only the gas flow Z on the right side of the rotating shaft 0-0 is shown, but the gas discharged to the outer peripheral side of the impeller 13 on the left side of the rotating shaft 0-0 is a casing. It flows along the outlet 11 to the outlet 11a and is blown out from there.

(3) Impeller transportation

When transporting the impeller 43, a plurality of impellers 43 are loaded in the rotation axis 0-0 direction. Here, the inter-blade portion 65 of the main plate 61 of the impeller 43 of the present embodiment is, as described above, circumferentially larger than the circumferential thickness of the blade 33, and radially. Each of the wings 33 is notched so as to extend from the outer peripheral edge to the inner peripheral edge of the wing 33 along the curved shape of the wing 33. Utilizing this shape, the two impellers 4 3 are moved from the rotation axis 0-0 direction. Overlap. The corresponding blades 33 of the other impeller 43 can be fitted into the cutouts of the plurality of blade portions 65 of one impeller 43. The two impellers 43 fitted in this way are further transported after being loaded to a predetermined loading height.

(4) Experimental example

The results of a noise measurement experiment performed on a multi-blade blower using the impeller of the present embodiment will be described.

In this experiment, a measurement experiment was performed on the conventional example shown in FIGS. 2 and 3 and on the present embodiment shown in FIGS. 5 and 6. In the present embodiment, for the purpose of reducing noise, the corrugated shape 64 formed on the main plate 61, the corrugated shape 66 formed on the side plate 62, and the inter-blade portion 65 of the main plate 61 are formed. The notched part is formed at the same time. Therefore, in order to confirm the noise reduction effect of each of these three shapes, we prepared an impeller molded with only one of each of these three shapes, and conducted a noise measurement experiment. The results of the noise measurement experiment are shown below.

① In the case of an impeller in which only the corrugated shape 6 4 is formed on the main plate 6 1

The noise value was reduced by 0.8 dB compared to the conventional example.

② In the case of an impeller in which only the corrugated shape 6 6 is formed on the side plate 6 2

The noise value was reduced by 0.5 dB compared to the conventional example.

(3) In the case of the impeller having only the shape in which the interblade portion 65 of the main plate 61 is notched, the noise value has been reduced by 0.5 dB compared to the conventional example.

From the above results, it was confirmed that the noise value was reduced in any of the three shapes applied for the purpose of reducing noise in the present embodiment.

(5) Characteristics of multi-blade blower

The features of the multi-blade blower of the present embodiment include the following.

① Noise reduction by the corrugated shape formed on the main plate of the impeller

In the conventional multi-blade fan 10, there is noise caused by turbulent vortices generated near the main plate 31. Specifically, it is caused by the following generation mechanism. As shown in Fig. 1 (b), a part of the gas sucked from the suction port 11b inside the impeller 13 collides with the main plate 31 in the vicinity of the main plate 31, and then the outer peripheral side. Some are flowing toward (see Gas Flow X). This gas flow X However, a turbulent vortex is generated due to the collision with the main plate 31. In the turbulent vortex, as the gas flow X moves toward the outer periphery, the flow colliding with the main plate 31 further joins. Then, the turbulent vortex of the gas flow X gradually develops and forms the largest turbulent vortex at the inner peripheral edge of the wing 33. The developed turbulent vortex is blown out toward the outer periphery by the wings 33, and noise is generated.

On the other hand, in the impeller 43 of the multi-blade blower 40 of the present embodiment, the corrugated shape 64 of the concavo-convex shape is formed at least in the vicinity of the inner peripheral edge of the blade 33 on the side of the side plate 62 of the main plate 61. As shown in Fig. 8 (a), the turbulent vortex developed due to the collision of the gas flow Z1 with the main plate 61 and the merging of the flows is collapsed just before reaching the wings 33, as shown in Fig. 8 (a). It becomes smaller. Thus, noise generated when the gas flow Z1 is extracted by the wings 33 can be reduced.

② Noise reduction by the corrugated shape formed on the side plate of the impeller

In the multiblade blower 10 of the conventional example, a swirling vortex having a vortex center near the outer peripheral end of the side plate 32 is generated. Since the swirling vortex does not contribute to the air blowing work of the impeller 13, as a result, it lowers the fan efficiency and causes noise. Specifically, it is caused by the following generation mechanism.

As shown in FIG. 1 (c), a part of the gas in the casing 11 is discharged to the outer periphery of the impeller 13 near the side plate 32, and then is discharged from the impeller 13. A swirling vortex Y is generated from the vicinity of the bellmouth 12 to the inner periphery of the impeller 13 again. Therefore, in the impeller 13, the ratio b ZB (hereinafter referred to as a blockage factor _BF ) of the axial length b of the portion where the swirl vortex Y is generated with respect to the axial total length B of the impeller 13 is given. For the corresponding part, the ventilation work has not been effectively performed. This results in reduced fan efficiency and noise.

On the other hand, in the impeller 43 of the multi-blade blower 40 of the present embodiment, since the corrugated shape 66 of the uneven shape is formed on the surface of the side plate 62 on the main plate 61 side, the impeller 4 of the side plate 62 is formed. (3) Pressure fluctuation near the outlet is reduced. Then, as shown in FIG. 8 (b), the gas flow discharged to the outlet side by the impeller 43 changes from the rotation axis side plate 62 side of the impeller 43 to the inner periphery of the impeller 43 again. Since it is difficult to be sucked into the side, the swirl vortex Z 2 generated near the side plate 62 is reduced. This reduces the _BF value to b 1 ZB 1 Since the portion of the small impeller 43 that can effectively perform the blowing work is increased, the efficiency of the blower is improved and the noise is reduced.

③ Noise reduction by cutting out the blades of the main plate of the impeller

In the impeller 43 of the multi-blade blower 40 according to the present embodiment, at least the front in the rotation direction of the inter-blade portion 65 located between the plurality of blades 33 of the main plate 61 is notched. As shown in (c), the turbulent vortex developed due to the collision of the gas flow Z3 with the main plate 61 and the merged flow forms a cut-off wing 6 just before being ejected by the wing 33. Part of the main plate 61 is relieved from 5 toward the outside in the axial direction. This makes it possible to reduce the noise generated when the wings 33 extract the gas flow, like the corrugated shape 64 formed on the main plate 61 shown in FIG. 8A.

Further, in the inter-blade portion 65 of the impeller 43 of the present embodiment, the front of the main plate 61 in the rotation direction is partially cut out in the circumferential direction, and the inter-blade portion 65 of the impeller 43 to the rear in the rotation direction of the inter-blade portion 65 is not included. Not notched. Therefore, there is no increase in gas flow separation behind the interblade 65 in the rotational direction. As a result, the effect of noise reduction by cutting off the front portion in the rotation direction of the interblade portion 65 is not impaired.

Further, the inter-blade portion 65 of the impeller 43 of the present embodiment is cut out from the outer peripheral edge to the inner peripheral edge of the blade 33, so that the turbulent vortex of the gas flow Z3 is generated by the blade. Before reaching the outer peripheral edge of 33, it is easy to escape from the cut-out space 65. Thereby, the turbulent vortex reaching the outer peripheral edge of the wing 33 can be further reduced, and the noise can be reduced.

向上 Improvement of loading efficiency during transportation of impeller

As described above, the inter-blade portion 65 of the main plate 61 of the impeller 43 of the present embodiment has, in the circumferential direction, a thickness greater than the circumferential direction of the blade 33 and a radial direction. Is cut off so that the curvature of the wing 33 extends from the outer peripheral edge to the inner peripheral edge of the wing 33 along the rib shape. By utilizing this shape, two impellers 43 can be overlapped from the rotation axis 0-0 direction, and the corresponding blades 33 can be fitted into the notches of the plurality of blade portions 65. Thereby, the loading efficiency when loading the impeller 43 can be improved.

[Second embodiment]

(Configuration of multi-blade blower) The multi-blade blower according to the second embodiment of the present invention includes an impeller 13 of the conventional multi-blade blower 10 shown in FIGS. 1 to 3, and an impeller 11 shown in FIGS. 9 and 10. O replaced

The impeller 1 13 is a resin product integrally formed by a mold, and includes a main plate 13 1, a side plate 13 2, and a plurality of blades 13 3. The main plate 13 1 is circular, and is rotated around a rotation axis 0-0 (see FIG. 1) by a motor 14. The main plate 13 1 is provided with a center hole 31 a, and the rotating shaft of the motor 14 is mounted in the center hole 13 a. The plurality of wings 133 are arranged annularly around the rotation axis 0-0, and extend along the rotation axis 0-0. One end of each wing 13 33 is fixed to the outer peripheral portion of the main plate 13 1. The side plate 1332 is an annular member and has an inner diameter that is the same as or slightly larger than the outer diameter of the main plate 1331. This side plate 13 2 is connected to the outer peripheral edge of the wings 13 3 at the other end of the plurality of wings 13 3. As shown in FIG. 10 (b), a cutout 13b is formed in a portion of the main plate 131 located between the adjacent wings 13 (hereinafter referred to as an inter-wing portion). ing. The notch 1 3 1b extends from the outer edge of the main plate 13 1 to the radial position of the inner edge of the wing 13 3, more specifically, from the outer edge of the main plate 13 1 to the wing 13 3 It has reached a position slightly inward of the inner edge from the radial position. The circumferential width of the notch 13 1 b is larger than the maximum value of the circumferential width of the blade 13. That is, the inter-blade portion of the main plate 13 1 is cut out larger than the cross-sectional outer dimension of the wing 13 3. In the space between the wings of the main plate 131, in addition to the notch 131b, there are a wing front plate 131c and a wing rear plate 13d. The wing front plate 13 G is an outer peripheral portion of the main plate 13 1 extending forward from the root of the wing 13 3 in the rotation direction. The wing rear plate portion 131d is an outer peripheral portion of the main plate 131 extending rearward in the rotational direction from the root of the wing 133.

As shown in FIG. 1, the casing 11 has an air outlet 11 a and an air inlet 11 b surrounded by a bell mouth 12. The suction port 1 1b faces the side plate 13 2 of the impeller 1 13. The outlet 11 a is formed so as to blow air in a direction substantially perpendicular to the rotation axis 0-0 of the impeller 113 so as to be orthogonal to the inlet 11 b.

(Features of multi-blade blower and impeller) (1) In the impeller 1 13 of the present embodiment, as shown in FIG. 11A, one of the impellers 1 The two impellers 1 1 3 and 1 1 3 are superimposed such that the other impeller 1 1 3 wing 1 3 3 is inserted between the wing 1 3 3 and the wing 1 3 3 be able to. At the time of superposition, the side plate 13 2 having an inner diameter equal to or larger than the outer diameter of the main plate 13 1 does not become an obstacle, and the cutout 13 1 b between the blades of the main plate 13 1 As the three wings 13 pass, the two impellers 1 13 and 1 13 are superimposed. Such overlapping is realized by forming a notch 1 31 b larger than the cross-sectional shape of the blade 13 3 in the inter-blade portion of the main plate 13 1.

As a result, as shown in Fig. 11 (b), the space efficiency during transportation has been improved by a factor of about 2, compared to the conventional method where only two impellers 13 'and 13' could be stacked. ing. If the notch 1 3 1b is large enough to allow two blades 1 3 3 to pass, it is possible to improve the space efficiency by about 3 times by stacking three impellers. .

(2) Notching the inter-blade part of the main plate 13 1 as described above, on the other hand, seems to impair the performance of the multi-blade fan, so we have not tried it before. The impeller was re-examined from various viewpoints and tests were conducted. The performance (efficiency and noise) of the blower was low even if a cut-out 13 1 b was provided between the blades of the main plate 13 1 It has been confirmed that it will not go down.

The reason why the performance of the multi-blade fan does not decrease even if the notch 1 3 1b is present is assumed as follows.

Among the gas flows in the multi-blade blower, there is a gas flow that is sucked into the inner peripheral space of the impeller 1 13 from the inlet 11 b and then collides with the main plate 13 1 and flows to the outer peripheral side. This gas flow contains turbulent vortices generated and developed by collision with the main plate 13 1 and merging with other gas flows. Then, the turbulent vortex generates noise when gas is discharged to the outer peripheral side of the impeller 113 by the blades 133. However, since the notch 13 板 b is provided between the wings of the main plate 13 ここ, the turbulent vortex passes through the notch 13 b 1 b just before the wing 13 3 0—Escaped in the 0 direction. For this reason, the noise is smaller than that of the conventional impeller without the notch 1 3 1b. It is thought to be. This noise reduction effect is presumed to play a role in compensating for any performance degradation due to the presence of the notches 13b.

(3) In the impeller 1 13 of the present embodiment, the inter-blade portion of the main plate 13 1 is substantially cut out from the radial position of the inner peripheral end of the wing 13 13 on the outer peripheral side (see FIG. 10 ( b)). Therefore, it is considered that the gas sucked into the inner peripheral space of the impeller 1 13 from the suction port 1 1 b is prevented from flowing unnecessarily to the back side of the main plate 13 1, and a decrease in the blowing efficiency was confirmed. It has not been.

多 The multi-blade blower of the present embodiment uses the impeller 113 which has good space efficiency during transportation and does not decrease in performance, so that the production cost can be reduced while maintaining the performance.

[Third embodiment]

In the impeller 1 13 of the second embodiment, the notch 1 3 1 b of the main plate 13 1 in the space between the wings is formed in the intermediate portion between the wings 13 3 and 13 3, If there is no problem, it is desirable to arrange the notch forward in the rotation direction of the wing as shown in FIGS.

(Configuration of impeller)

In the present embodiment, an impeller 2 13 shown in FIGS. 12 and 13 is used instead of the impeller 113 of the second embodiment. The impeller 2 13 includes a main plate 2 3 1, a side plate 1 3 2, and a plurality of blades 1 3 3. The main plate 2 31 is circular, and is rotated about a rotation axis 0-0 (see FIG. 1) by a motor 14. The main plate 231 is provided with a center hole 231a, and the rotation shaft of the motor 14 is mounted in the center hole 231a. The plurality of wings 133 are arranged annularly around the rotation axis 0-0, and extend along the rotation axis 0-0. One end of each wing 13 3 is fixed to the outer peripheral portion of the main plate 2 31. The side plate 1332 is an annular member and has an inner diameter that is the same as or slightly larger than the outer diameter of the main plate 231. This side plate 13 2 is connected to the outer peripheral edge of the wings 13 3 at the other end of the plurality of wings 13 3.

As shown in Fig. 13 (b), a notch 2 3 1b is formed in a portion of the main plate 2 3 1 located between adjacent wings 1 3 (hereinafter referred to as an inter-blade portion). ing. This notch 2 3 1b is located in the radial direction from the outer peripheral edge of the main plate 2 3 1 to the inner peripheral edge of the wing 1 3 3. In particular, it extends from the outer peripheral edge of the main plate 231 to a position slightly inward of the radial position of the inner peripheral edge of the wing 133. Also, the circumferential width of the notch 2 3 1 b is larger than the maximum circumferential width of the wing 1 33. That is, the inter-blade portion of the main plate 23 1 is cut out to be larger than the cross-sectional outer dimension of the wing 13 3. Further, the notch 2 3 1 b is cut out from the root in the rotation direction of the wing 13 3, and there is no plate between the wing 13 3 and the notch 2 3 1 b. In other words, only the wing rear plate portion 2131d extending rearward in the rotational direction from the root of the wing 133 exists in the space between the wings of the main plate 231 (see Fig. 13 (b)).

(Features of the impeller)

In the impeller 2 13 of the present embodiment, the notch 2 3 1 b is provided in a portion of the inter-blade portion of the main plate 2 3 1 in the rotation direction front of the blade 1 3 3. By notching the interblade in this way, the impeller 2 13 not only maintains the performance but also improves the performance when the interblade is not cut. Although this could not be imagined in the past, it is considered that the noise has been reduced and the performance of the multi-blade fan has been improved for the following reasons.

First, as in the second embodiment, the notch 231 is provided in the space between the wings of the main plate 231, so that the turbulent vortex is notched immediately before being released by the wing 1333. It is presumed that the noise is released to the outside in the axis 0-0 direction through 2 3 1b, and the noise is smaller than that of the conventional impeller without the notch 2 3 1b.

Further, in the present embodiment, since the blade portion of the main plate 2 31 of the impeller 2 13 is cut away from the root of the blade 13 3 in the rotation direction forward, the blade rear plate portion 2 3 1 d A sufficient circumferential width can be ensured, and the gas flow separation phenomenon behind the blades 133 in the rotation direction can be more effectively suppressed. For this reason, it is presumed that the noise is lower than in the second embodiment.

[Fourth embodiment]

(1) Configuration of centrifugal blower

The sirocco fan according to one embodiment of the present invention replaces the impeller 13 of the conventional sirocco fan 10 shown in FIGS. 1 to 3 with the impeller 11 13 shown in FIGS. 14 and 15. It is a thing. (2) Configuration of impeller

The impeller 1 1 1 3 is a resin product integrally molded from a resin material by a mold. As shown in FIG. 15, the main plate 1 1 3 1, the side plate 1 1 3 2, and the plurality of blades 1 1 It is composed of 33. The main plate 113 is circular, and is rotated by a motor 14 about a rotation axis 110 (see FIG. 1). The main plate 1 1 3 1 is provided with a center hole 1 1 3 1 a, and the rotating shaft of the motor 14 is mounted in the center hole 1 1 3 1 a. The plurality of wings 1 1 3 3 are annularly arranged around the rotation axis 0-0, and extend along the rotation axis 0-0. One end of each wing 1 1 3 3 is fixed to the outer peripheral portion of the main plate 1 1 3 1. The side plate 113 is an annular member, and has an inner diameter that is the same as or slightly larger than the outer diameter of the main plate 113. The side plate 1 1 3 2 is connected to the outer peripheral edge of the wings 1 1 3 3 at the other end of the plurality of wings 1 1 3 3.

The multiple wings 1 1 3 3 extending from the main plate 1 1 3 1 along the rotation axis 0-0 are bent forward in the rotation direction from the middle as shown in Fig. 14, Fig. 15, Fig. 17 and Fig. 18. The tip (the other end) is connected to the side plate 113. Therefore, as shown in Fig. 18, the wing 1 1 3 3 is composed of a main body 1 1 3 3 a on the main plate 1 1 3 1 side and an inclined section 1 1 3 3 b on the side plate 1 1 3 2 side. Will be done.

In addition, the main plate 1 13 1 has a cut-out portion in which the inclined portion 1 1 3 3 b of the wing 1 1 1 3 3 is projected on the main plate 1 1 3 1 along the rotation axis 0-0. As a result, a cutout 1 1 3 1 b is formed on the main plate 1 1 3 1 between the wing 1 1 3 3 and the adjacent wing 1 1 3 3. These notches 1 13 1 b have a shape reaching the outer peripheral edge of the main plate 1 13 1, as shown in FIG.

The notch 1 1 3 1 b has the wing 1 1 3 3 of the main plate 1 1 3 1 because the slope 1 1 3 3 b of the wing 1 1 3 3 is inclined forward in the rotation direction. It is located at the front in the rotation direction of the part (see Figures 16 and 17).

(3) Features of sirocco fans and impellers

(1) Here, the wing 1 1 3 3 is bent at an appropriate position, and the wing 1 1 3 3 is provided with an inclined portion 1 1 3 3 b. Therefore, each position along the rotation direction 0-0 of the wing 1 1 3 3 The difference in the amount of inflow and outflow of air is small, and the ventilation efficiency is improved and noise is suppressed. Also, the wings 1 1 3 3 are provided with an inclined section 1 1 3 3 b and cut into the main plate 1 1 3 1 A notch 1 1 31b is formed to remove the interfering object (main plate) from the projection of the slope 1 1 133b. For this reason, as shown in FIG. 19, the pair of dies 1 060 and 1 070 form an impeller 1 113 composed of a main plate 1 131, side plates 1 132 and wings 1 133 from a resin material. Can be molded.

The molds for resin molding the impellers 1 1 1 1 3 are an upper mold 1 060 and a lower mold 1 070 shown in FIG.

The upper mold 1060 has a protrusion 1 061 that enters between the wings 1 133 and 1 133. The projection 1 061 has a vertical surface 1 061 a that forms the rear surface of the main body 1 133 a of the wing 1 133 a in the rotation direction, and a rear surface in the rotation direction of the inclined portion 1 133 b of the wing 1 133 a. An inclined surface 1061 b that forms the surface, a horizontal surface 1061 c that forms the surface of the main plate 1 131 on which the wings 1 133 are attached, and the like are formed.

The lower mold 1070 has a protruding portion 1071, which extends downward from the cutout 1131b after molding. Further, a tip portion 1072 of the protruding portion 1071 has a tapered shape. Such a lower mold 1 070 has a horizontal plane 1 070a that forms the surface of the main plate 1 1 31 without the wings 1 133, and the main body 1 1 33a of the wing 1 133 A vertical surface 1 071 a forming a surface, an inclined surface 1 072 a forming a front surface in the rotation direction of the inclined portion 1 133 b of the wing 1 133 are formed. The vertical surface 1071a is a surface of the protruding portion 1071, and the inclined surface 1072a is a surface of a tip portion 1072 of the protruding portion 1071.

In the case of such an upper mold 1060 and a lower mold 1070, the impeller 1 1 13 including the inclined portion 1 133 b of the wing 1 133 is formed, and then both the molds 1 060 and 1 070 are formed. It can be pulled up and down. In this way, the lower die 1070, which enters the notch 1 1 31b of the main plate 1 31 to form the inner surface of the inclined portion 1 133b, and the outer surface of the inclined portion 1 133b from the opposite side, With the upper mold 1060 to be formed, the wings 1 133 and the impellers 1 1 1 3 which can not be integrally formed and which have the inclined portion 1 133 b can be formed.

By the way, here, the main plate 1 131 is cut off at the projected portion of the inclined portion 1 133 b of the wing 1 133 so that the impeller 1 1 13 can be integrally formed by a pair of molds 1 060 and 1070. However, conventionally, the main plate 1 The lack of this has not been tried before, as it is felt on the other hand as degrading the performance of the sirocco fan. However, here, the structure of the impeller was reviewed from various viewpoints, and even if the main plate 1 13 1 1 was cut off for the projected portion of the inclined portion 1 1 3 3 b of the wing 1 1 3 3 as described above, We came to recognize that the performance (efficiency and noise) of the fan did not decrease, and that the performance improvement due to the presence of the inclined portion 113 b was an advantage. Based on this finding, the impeller 1 1 1 3 according to the present embodiment has been produced, and the impeller 1 1 1 3 has improved ventilation efficiency and reduced noise as compared with the conventional one.

(2) Here, the notch 1 1 3 1 b of the main plate 1 1 3 1 including the projection of the slope 1 1 3 3 b of the wing 1 1 3 3 is changed to the main plate 1 1 3 1 as shown in Fig. 16. Reach the outer edge of Therefore, the lower mold 1 0 7 0 used for integral molding is composed of a portion that covers the outer peripheral edge of the main plate 1 1 3 1 and a notch 1 1 3 1 The structure is directly connected to 1 and the strength as a mold is easily secured.

(3) Here, the inclined portion 1 1 3 3 b of the wing 1 1 3 3 is inclined forward in the rotation direction, and the main plate 1 1 3 1 is cut off in the rotation direction forward portion of each wing 1 1 3 3. (See Figure 18). By notching the main plate 1 13 1 in this way, the impeller 1 1 13 can not only maintain its performance but also improve its performance as compared with the case where the notch 1 1 3 1 b is not provided. Although this could not have been imagined in the past, the turbulent vortex contained in the gas flowing toward the outer periphery after colliding with the main plate 1 1 3 1 escapes from the notch 1 1 3 1 b in the direction of the rotation axis 0-0 This has resulted in improved performance with reduced noise. Accordingly, in the impeller 1 1 13 of the present embodiment, in addition to the performance improvement due to the presence of the inclined portion 1 1 3 3 b of the wing 1 1 3 3, notch 1 1 3 1 b The advantage of noise reduction due to the provision of this can be enjoyed.

(4) Modified example of wing

(A)

By using the wings 1 2 3 3 shown in Fig. 20 instead of the wings 1 1 3 3 shown in Fig. 18, integral resin molding is possible, resulting in a low noise impeller. .

The plurality of wings 1 2 3 3 extending from the main plate 1 1 3 1 are entirely inclined forward in the rotation direction as shown in FIG. Further, the main plate 1 131 has a cutout portion in which the entire wing 1 233 is projected on the main plate 1 131 along the rotation axis 0-0. As a result, the wing 1

A notch 1 1 31 c is formed between 233 and the adjacent wing 1 233. Since the wings 1233 are inclined forward in the rotational direction, these cutouts 1 1 31 c are arranged in the rotationally forward portion of the main plate 1 131 with the wings 1 233.

(B)

Even if the blade 1 333 having the vertical cross section shown in FIG. 21 is used in place of the blade 1 133 having the vertical cross section shown in FIG. 18, the resin can be integrally molded and a low noise impeller can be obtained.

As shown in FIG. 21, the plurality of wings 1 333 extending from the main plate 1 131 are bent forward in the rotation direction from the root portion connected to the main plate 1 131, and the rotation axis 0-0 Parallel. Then, in the vicinity of the side plate 1 132, it is again bent forward in the rotation direction, and the tip is connected to the side plate 1 132. Therefore, as shown in FIG. 21, the wing 1 333 has an inclined portion 1 333 c on the main plate 1 131 side, an inclined portion 1 333 b on the side plate 1 132 side, and both inclined portions 1 333 b and 1 333 c. And the main body 1333a.

In addition, the main plate 1 131 has a cut-out portion in which both inclined portions 1 333 b and 1 333 c of the wing 1 333 are projected onto the main plate 1 131 along the rotation axis 0-0. As a result, the main plate 1 131 has a notch 1 131 d formed between the wing 1 333 and the adjacent wing 1 333. These cutouts 1 1 31d the wings 1

Since 333 is inclined forward in the rotation direction, it is arranged in the rotation direction forward portion of the main plate 1 131 where the wing 1 333 is attached (see FIG. 21).

Here, since a plurality of inclined portions 1 333b and 1 333c are formed on the wing 1 333, it is possible to more finely adjust the amount of gas flowing in and out at each position of the wing 1 333. The difference in the amount of gas inflow and outflow at each position of 333 can be made smaller.

(C)

A wing 1 133 having a vertical cross section shown in FIG. 18 (instead, a wing 1 433 having a vertical cross section shown in FIG. 22 may be used. The plurality of wings 1 4 3 3 extending from the main plate 1 1 3 1 along the rotation axis 0-O are bent backward in the rotation direction from the middle as shown in Fig. 22 and the tip (the other end) is the side plate 1 1 3 Connected to two. Therefore, the wing 1443 is composed of the main body 1443a on the main plate 113 side and the inclined and inclined portions 144b on the side plate 113 side. In addition, the main plate 1 13 1 has a cut-out portion in which the inclined portion 1 4 3 3 b of the wing 1 4 3 3 is projected on the main plate 1 1 3 1 along the rotation axis 0-0. As a result, a cutout 1 1 3 1 e is formed on the main plate 1 1 3 1 between the wing 1 4 3 3 and the adjacent wing 1 4 3 3. These notches 1 1 3 1 e have wings 1 4 3 3 of the main plate 1 1 3 1 because the slope 1 4 3 3 b of the wing 1 4 3 3 is inclined backward in the rotation direction. It is arranged at the rear part in the rotation direction of the part.

(D)

Instead of the wings 1 133 having the inclined portion 113 b shown in FIG. 17, the wings 150 3 3 having the inclined portion 135 33 b shown in FIG. 23 can be used.

The plurality of wings 1 5 3 3 extending from the main plate 1 1 3 1 are bent forward in the rotation direction from the middle, and the tips (the other ends) are connected to the side plates 1 1 3 2. Therefore, as shown in Fig. 23, the wing 1 53 3 is composed of a main body 1 15 3 3a on the main plate 1 1 3 1 side and an inclined portion 1 5 3 3 b on the side plate 1 1 3 2 side. Will be done. The inclined portion 1 5 3 3 b has a large forward inclination in the rotation direction on the inner peripheral side and a smaller inclination on the outer peripheral side.

In addition, the main plate 1 13 1 has a cut-out portion in which the inclined portion 1 5 3 3 b of the wing 1 5 3 3 is projected on the main plate 1 1 3 1 along the rotation axis 0-0. As a result, a cutout 1 1 3 1 f is formed on the main plate 1 1 3 1 between the wing 1 5 3 3 and the adjacent wing 1 5 3 3. These notches 1 1 3 1 f reach the outer peripheral edge of the main plate 1 1 3 1, but the width dimension of the part that goes outward is small.

If the width of the part that goes outside of this notch 1 1 3 1 f is small, it is difficult to secure the strength of the mold for molding the impeller integrally with the resin, so the notch is used to avoid this. 1 13 1 f may be expanded to form notches 1 13 1 g as shown in FIG. 24 in the main plate 1 13 1. The notch 1 1 3 1 g includes the projected portion of the wing 1 5 3 3 on the main plate 1 1 3 1 along the axis of rotation 0-0 along the inclined portion 1 5 3 3 b of the wing 15 3 3 While reaching the outer peripheral edge while maintaining This cut If the notch 1 1 3 1 g is formed, a part of the mold that enters the notch 1 1 3 1 g will be firmly connected to the mold body located around the main plate 1 1 3 1. (4) It is easy to secure the strength of the mold.

(E)

Instead of the wing 113 having the inclined portion 11333b shown in FIG. 17, a wing 163 having the inclined portion 16333b shown in FIG. 25 can be used.

The plurality of wings 1633 extending from the main plate 113 are bent forward in the rotational direction from the middle, and the ends (the other ends) are connected to the side plates 113. Therefore, the wing 1633, as shown in Fig. 25, is composed of the main body 1163a on the main plate 1131 side and the inclined portion 16333b on the side plate 1132 side. Will be done. The inclined portion 1 6 3 3 b has a smaller inclination on the inner peripheral side and a larger inclination on the outer peripheral side in the rotation direction.

In addition, the main plate 1 13 1 is notched at a projected portion where the inclined portion 16 3 3 b of the wing 16 3 3 is projected on the main plate 1 13 ″ I along the rotation axis 0-0. As a result, a cutout 1 1 3 1 h is formed on the main plate 1 1 3 1 between the wing 1 6 3 3 and the adjacent wing 1 6 3 3.

[Fifth Embodiment]

In the fourth embodiment, the present invention is applied to a sirocco fan, which is one of centrifugal fans, but the present invention can be applied to other centrifugal fans, for example, a turbo fan. . In this case, the projected portion of the turbofan blade, which is entirely inclined, projected onto the main plate along the rotation axis is cut out, so that the main plate and the multiple blades can be integrally molded with only a pair of upper and lower molds. May be configured. The shroud, which corresponds to the side plate of the sirocco fan, will be installed on the main plate and the multiple wings, which are molded integrally.

As described above, if the present invention is applied to a turbofan in which each blade is conventionally formed using a slide, the main plate and the blade can be formed only by the upper die and the lower die. The cost and molding time can be reduced, and a low-cost turbofan can be provided.

[Other embodiments]

(A) In the impeller of each of the above embodiments, a part of the inter-blade portion of the main plate is cut out. However, if there is no problem in strength and a slight reduction in performance is allowed, the blade is not a part of the inter-blade portion. It is possible to choose to cut out all the parts to maximize space efficiency.

(B)

The inventions described in the first to third embodiments can be applied not only to a resin-made impeller integrally formed, but also to a sheet-metal-made impeller.

Industrial applicability

By using the present invention, in an impeller of a multi-blade blower, noise generated when a gas flow is emitted by a blade can be reduced.

Claims

The scope of the claims

1. A main plate (61, 231, 1131) rotating about a rotation axis (0-0) and an annular arrangement around the rotation axis (0-0), and one end of each of the main plates (61, 231, 1 131) fixed to the wings (33, 133, 1 133 3-1333, 1533, 1633) and

An annular side plate (62, 132, 1132) connecting the other ends of the plurality of wings (33, 133, 1133 to 1333, 1533, 1633);

With

The inter-blade portion of the main plate (61, 231, 1131) located between the wings (33, 133, 1133 to 1333, 1533, 1633) is at least the wing (33, 133, 1133). ~ 1333, 1533, 1633) are cut off in the rotation direction,

Impellers of multi-blade blowers (43, 213, 11 13).

2. The side plate (62, 132, 1132) has an inner diameter equal to or larger than the outer diameter of the main plate (61, 231, 1131);

The wing portion (33, 133, 1133) of the main plate (61, 231, 1131) located between the plurality of wings (33, 133, 1133 to 1333, 1533, 1633) is provided. ~ 1333, 1533, 1633)

The impeller (43, 213, 1113) of the multi-blade blower according to claim 1.

3. The impeller (43, 213, 1113) of the multi-blade blower according to claim 1 or 2, wherein the inter-blade portion is partially notched in a circumferential direction.

4. The said wing | blade part is notched from the outer periphery side edge of the said wing (33, 133, 1133-1333, 1533, 1633) from the inner periphery side edge, The 1-3 of Claims 1-3. The impeller of a multi-blade blower as described in any of them (43, 213, 113).

5 ■ Each of the wings (1133-"! 333, 1533, 1633) has an inclined portion (1133b-1333b, 1333c, 153) that is inclined forward in the rotation direction. 3 b, 1633 b)

The inter-blade portion is at least an inclined portion (1 133 b to 1 333 b, 1 333 c, 1 533 b, 1 633 b) of each of the wings (1 133 to 1 333, 1 533, 163 3). The projection of is cut off,

The impeller of a multi-blade blower according to any one of claims 1 to 4.

6. The impeller (111) of a multi-blade fan according to claim 5, wherein the plurality of blades (1233) are entirely inclined.

7. The impeller (43, 213, 1113) according to any one of claims 1 to 6, driving means (14) for rotating the main plate (61, 231, 1131), and the side plate (62, 1 32, 1 1 32) Suction port (1

1b) and an outlet (11a) which is provided on the outer peripheral side of the impeller (43, 213, 1113) and sends out gas in a direction substantially perpendicular to the rotating shaft (0-0). And a casing (11) covering the impeller (43, 213, 1113).

Multi-blade blower with.