JP4857495B2 - Impeller of multi-blade fan and multi-blade fan equipped with the impeller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impeller of a multi-blade fan and a multi-blade fan provided with the impeller, and more particularly, an impeller of a multi-blade fan in which ends of a plurality of blades extending from a main plate are connected by an annular side plate and a multi-blade equipped with the impeller It relates to a wing blower.
[0002]
[Prior art]
In a gas conditioner (hereinafter referred to as an air conditioner) such as a gas cleaner or an air conditioner, a multi-blade blower is used to blow air. 1 to 3 show conventional examples of multiblade fans. Here, FIG. 1 shows a side view of a conventional multi-blade fan, FIG. 2 shows a side view of an impeller of the conventional multi-blade fan, and FIG. 3 shows a plan view of the impeller of the conventional multi-blade fan. The figure is shown.
[0003]
The multiblade fan 10 includes an impeller 13, a casing 11 covering the impeller 13, a motor 14 for rotating the impeller 13, and the like. In the impeller 13, one end of a plurality of blades 33 is fixed to the 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 is formed with a gas outlet 11 a and a gas inlet 11 b surrounded by the bell mouth 12. The suction port 11 b faces the side plate 32 of the impeller 13. Moreover, the blower outlet 11a is formed in the direction orthogonal to the suction inlet 11b so that gas may be blown out in the direction substantially orthogonal to the rotation axis OO of the impeller 13.
[0004]
When the multi-blade fan 10 is operated by rotating the motor 14, the impeller 13 rotates in the direction of the rotation direction R in FIG. 3 with respect to the casing 11. As a result, each blade 33 of the impeller 13 pressurizes and discharges gas from the inner space to the outer space, and the gas is sucked into the inner space of the impeller 13 from the suction port 11b. The gas pushed out to the outer peripheral side of the impeller 13 is sent out through the blower outlet 11a. That is, the multiblade blower 10 sucks gas from the suction port 11b and sends out gas from the blower port 11a.
[0005]
[Problems to be solved by the invention]
In such a multiblade fan 10, there is noise due to separation of gas flow generated on the rear side in the rotation direction of each blade 33. Specifically, noise is generated by the following generation mechanism.
[0006]
Inside the impeller 13, the gas sucked from the suction port 11 b flows mainly from the direction toward the main plate 31 toward the outer periphery as shown in FIG. 1 (see gas flow V). Further, when focusing attention on the gas flow V in the portion of the blade 33, as shown in FIG. 4, the gas sucked from the suction port 11 b is scraped mainly to the outer peripheral side of the impeller 13 by the front side in the rotation direction of the blade 33. It is flowing to be put out. However, since the separation vortex X is generated on the rear side of the blade 33 in the rotation direction, the gas flow V is separated from the rear side of the rotation direction of the blade 33 in the circumferential direction by a width W. Due to this disturbance width W, noise is generated in the multiblade fan 10.
[0007]
Further reduction in noise is required for multiblade fans used in air conditioners.
[0008]
The subject of this invention is providing the impeller which can reduce the noise resulting from the peeling of the gas flow produced on the rotation direction back side of a wing | blade, and providing the low noise multiblade fan.
[0009]
[Means for Solving the Problems]
The multiblade fan according to claim 1 includes an impeller, a driving unit that rotates a main plate of the impeller, and a casing that covers the impeller. The impeller includes a main plate rotating around a rotation axis, a plurality of blades, and an annular side plate. The plurality of blades are members that are arranged in an annular shape around the rotation axis, and one end of each of the blades is fixed to the main plate. The side plate is a member that connects the other ends of the plurality of blades. Furthermore, at least one of the plurality of wings has a protrusion toward the inner peripheral side while being inclined toward the side plate at a part of the inner peripheral side edge. The casing has a suction port facing the opening on the inner peripheral side of the side plate and a blower outlet that is provided on the outer peripheral side of the impeller and sends out gas in a direction substantially orthogonal to the rotation axis. Moreover, the end surface of the blade on the side plate side extends toward the inner peripheral side while inclining so as to protrude from the side plate toward the suction port side.
[0010]
In this multiblade blower, when the main plate is rotated by the driving means, the impeller rotates relative to the casing. Then, each blade of the impeller pressurizes and discharges gas from the space on the inner peripheral side to the space on the outer peripheral side, and the gas pushed out from the suction port to the outer peripheral side of the impeller is sent out through the outlet. That is, the multiblade blower sucks gas from the suction port and sends gas from the blower outlet.
[0011]
Here, in the impeller of the conventional multiblade fan, the inner peripheral side edge of the blade extends straight from the main plate toward the side plate.
[0012]
On the other hand, in the multi-blade fan, a portion of the inner peripheral edge of the blade of the impeller is provided with a protrusion toward the inner circumferential side while inclined to the side plate direction. This protrusion disturbs the flow to be separated behind the blade in the rotational direction. Since this disturbed flow reattaches to the blade, as a result, the generation of separation vortices generated on the rear side in the rotation direction of the blade is suppressed, the turbulence width is reduced, and noise can be reduced.
[0013]
The projections may be provided on all of the plurality of wings, or may be provided on only one or several, and are determined in consideration of the noise reduction effect.
[0014]
Moreover, in this multiblade blower, the end surface of the blade on the side plate side extends toward the inner peripheral side while inclining so as to protrude from the side plate toward the suction port side, so that a flow rectifying effect near the suction port can be obtained. it can.
[0015]
Multiblade blower according to claim 2, chord length of the wing is smaller stepwise from one end to the other end of the wing.
[0016]
Multiblade blower according to claim 3, in claim 2, chord length of the other end is less 0.85 times the chord length of the end.
[0017]
The multi-blade fan this, chord length of the blade of the impeller has to smaller shape stepwise from one end to the other end of the wing. Due to this shape, the flow to be separated at the rear of the blade in the rotation direction is disturbed and reattached to the blade. As a result, the generation of separation vortices generated on the rear side in the rotation direction of the blade is suppressed, the turbulence width is reduced, and noise can be reduced.
[0018]
Also, in this impeller of a multiblade blower, the longest one range of 0.85 times or less the length of the chord length of the wing chord shortest other end than the length (shroud side) of the (main plate side) It is desirable to do.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
(1) Configuration of Multi-blade Fan A multi-blade fan (centrifugal blower) according to an embodiment of the present invention includes a plurality of blades in the impeller 13 of the conventional multi-blade fan 10 shown in FIGS. The only difference is that the chord length is reduced stepwise from the end on the main plate side of the wing toward the end on the side plate side.
[0020]
FIG. 5 shows a side view of the multi-blade fan 40 of the present embodiment, and FIGS. 6 and 7 show a side view and a plan view of the impeller 43 of the multi-blade fan 40.
[0021]
The multiblade fan 40 mainly includes an impeller 63, a casing 11 that covers the impeller 63, and a motor 14 that rotates the impeller 43.
[0022]
In the impeller 43, a plurality of blades 33 are fixed to the outer peripheral edge of a disk-shaped main plate 61, and the other ends of the plurality of blades 63 are connected by an annular side plate 62. Details of the impeller 43 will be described later.
[0023]
The casing 11 is formed with a gas outlet 11 a and a gas inlet 11 b surrounded by the bell mouth 12. The suction port 11 b is disposed so as to face the side plate 62 of the impeller 43. The gas flowing through the suction port 11b to the space of the inner peripheral portion of the impeller 43 flows in a form substantially along the rotational axis OO of the impeller 43, and the rotational axis OO is rotated by the rotation of the impeller 43. It flows in the direction away from (the outer peripheral direction of the impeller 43). Moreover, the blower outlet 11a is formed so as to be orthogonal to the suction inlet 11b so as to blow out gas in a direction substantially orthogonal to the rotation axis OO of the impeller 43.
[0024]
The rotation shaft of the motor 14 is mounted in the center hole 61a (see FIG. 6) of the main plate 61, and the impeller 43 is rotated by rotating the main plate 61. The main body portion of the motor 14 is fixed to the casing 11.
[0025]
Next, the impeller 43 will be described in detail.
[0026]
As shown in FIGS. 6 and 7, the impeller 43 includes a main plate 61, a plurality of blades 63, and an annular side plate 62. In this embodiment, the impeller 43 is a resin product in which all of the main plate 61, the plurality of blades 63, and the side plates 62 are integrally formed using a mold.
[0027]
The main plate 61 is a disk-shaped member in which a center hole 61a is formed, and the rotation shaft of the motor 14 is fixed to the center hole 61a. A plurality of holes 61b (six in this embodiment) penetrating the main plate 61 are formed on the outer peripheral side of the center hole 61a. Further, a plurality of wings 63 described later are formed at equal intervals in the rotation direction on the outer peripheral edge of the main plate 61.
[0028]
The wing 63 is a member having a concave shape in front of the rotation direction and arranged at equal intervals in a plurality of rotation directions around the rotation axis OO. One end of the wing 63 is fixed to the outer peripheral edge of the main plate 61, extends from there along the rotation axis OO without being twisted, and the other end is fixed to the inner peripheral edge of the side plate 62.
[0029]
The wing 63 has a shape in which the chord length decreases stepwise as it extends from the main plate 61 side to the side plate 62 side. Specifically, as shown in FIG. 8, the wing 63 is formed most on the main plate 61 side. The first wing portion 64, the second wing portion 65 formed on the side plate 62 side of the first wing portion 64, and the third wing portion 66 formed on the side plate 62 side most.
[0030]
The chord length L1 of the first wing portion 64 is the longest, the chord length L2 of the second wing portion 65 is long, and the chord length L3 of the third wing portion 66 is shortest. That is, as shown in FIG. 6, the second wing portion 65 is directed toward the inner circumferential side by a length corresponding to the difference between the two chord lengths L2 and L3 with respect to the third wing portion 66. A projecting second corner 65a (projection) is formed. Similarly, the first wing portion 64 projects from the second wing portion 65 toward the inner peripheral side by a length corresponding to the difference between the two chord lengths L1 and L2. 64a (protrusion) is formed.
[0031]
Further, as shown in FIG. 8A, the second wing part 65 is formed so as to be included in the cross section of the first wing part 64, and the third wing part 66 is included in the cross section of the second wing part 65. Is formed.
[0032]
In the present embodiment, the chord length of the wing 63 is changed in three stages, but may be changed in any number of stages as long as it is a plurality of stages. In this embodiment, the chord length ratio L3 / L1 is set to 0.85. However, the ratio is not limited to this value, and may be in the range of 0.85 or less.
[0033]
The annular side plate 62 is disposed on the outer peripheral side of the other end of the blade 63 and connects all the blades 63. The side plate 62 is also integrally formed with the main plate 61 and the plurality of wings 63.
[0034]
(2) Molding of Impeller The impeller 43 having the above-described configuration is obtained by integrally molding a resin by using two molds 71 and 72.
[0035]
In the molds 71 and 72, the portion for forming the wing 63 has a shape as shown in FIG. As shown in FIG. 10, when the molds 71 and 72 are combined, the impeller 43 including the wing parts 64, 65, and 66 of the wing 63 is formed by the wing forming parts 71a and 72a of the respective molds. The Thereafter, the molds 71 and 72 are pulled out on both sides.
[0036]
(3) Operation of the multiblade fan When the motor 14 is rotated to operate the multiblade fan 40, the impeller 43 rotates in the direction of the rotation direction R shown in FIG. That is, in the multiblade fan 40, the pressure of the gas is increased and released by the front surface in the rotational direction which is mainly the concave surface of the blade 63. As a result, the blades 63 of the impeller 43 pressurize and release the gas from the inner space of the impeller 43 to the outer space, and the gas is sucked into the inner space of the impeller 43 from the suction port 11b. At the same time, 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 Y in FIG. 5). That is, the multiblade blower 40 sucks the gas from the suction port 11b along the rotation axis OO, and sends the gas from the blowout port 11a in a direction orthogonal to the rotation axis OO. In FIG. 5, only the gas flow Y on the right side of the rotation axis OO is displayed, but the gas released to the outer peripheral side of the impeller 43 on the left side of the rotation axis OO is along the casing 11. It flows to the blower outlet 11a and blows out from there.
[0037]
(4) Experimental example The result of having conducted the noise measurement experiment about the multiblade fan using the impeller of this embodiment is demonstrated.
[0038]
Noise measurement was performed on the conventional example shown in FIGS. 1 to 3 and the present embodiment shown in FIGS. As a result, in the multiblade fan using the impeller of this embodiment, it was confirmed that the noise value was reduced by 0.5 dB compared to the conventional example.
[0039]
(5) Features of the multiblade fan The features of the multiblade fan of the present embodiment are as follows.
[0040]
<1> Noise reduction by a shape in which the blade chord length of the blade is changed stepwise (projection toward the inner peripheral side at the inner peripheral side edge of the blade) In the impeller 43 of the multiblade blower 40 of the present embodiment, the blade The chord length of 63 has a shape that decreases stepwise in order of the first wing portion 64, the second wing portion 65, and the third wing portion 66 from one end of the wing toward the other end. The second wing portion 65 has a second corner portion 65a that protrudes toward the inner circumference side by a length corresponding to the difference between the two chord lengths L2 and L3 with respect to the third wing portion 66. The first wing portion 64 is formed with a first corner portion 64a projecting toward the inner peripheral side by a length corresponding to the difference between the two chord lengths L1 and L2 with respect to the second wing portion 65. Is formed. That is, protrusions are formed on the inner peripheral edge of the blade 63 by changing the chord length of the blade 63 in a stepped manner.
[0041]
As shown in FIG. 11, the flow to be separated at the rear of the blade 63 in the rotational direction is disturbed and reattached to the blade due to the shape of the blade 63, resulting in the rear of the blade 63 in the rotational direction. Generation of the separation vortex X1 is suppressed, and the disturbance width W1 becomes smaller than the disturbance width W of the conventional example. Thereby, noise can be reduced.
[0042]
<2> Ease of Molding When Resin-Integrated Molding In this embodiment, in addition to the chord length being stepped, as shown in FIG. Since it is formed so as to be included in the cross section of the first wing part 64 and the third wing part 66 is formed so as to be included in the cross section of the second wing part 65, in the case of integrally molding the impeller 43, It has a shape that can be easily removed. Accordingly, it is not necessary to use a special mold, and the resin integral molding by the simple molds 71 and 72 shown in FIGS. 9 and 10 is possible.
[0043]
[Second Embodiment]
As shown in FIG. 6, the first corner portion 64a and the second corner portion 65a of the wing 63 of the above-described embodiment protrude straight toward the inner peripheral side, and the end surface of the wing 63 on the side plate 62 side is also inward. It extends straight towards the circumference. On the other hand, the impeller 73 of the multiblade blower of the present embodiment has blades 93 formed so that these portions are directed toward the inner peripheral side while being inclined in the side plate direction. Specifically, as shown in FIG. 12, the first corner portion 94 a and the second corner portion 95 a of the wing 93 protrude toward the inner peripheral side while being inclined toward the side plate 92 , and the wing 93 has a side plate 92 side. The end surface extends to the inner peripheral side while inclining in a direction protruding from the impeller 73 to the outside (in the suction port direction).
[0044]
Also in the present embodiment, noise can be reduced as in the above-described embodiment, and the mold can be easily removed even when the resin is integrally molded. Furthermore, in this embodiment, since the end surface of the blade 93 on the side plate 92 side extends to the inner peripheral side while inclining in the direction protruding from the impeller 73, it also has a flow rectifying effect near the suction port. .
[0045]
[Other Embodiments]
In the said embodiment, although this invention is applied to the multiblade fan using the resin-made impeller, this invention is applicable also to the multiblade fan using the sheet-metal impeller.
[0046]
【Effect of the invention】
As described above, according to the present invention, the following effects can be obtained.
[0047]
In the invention according to claims 1 to 3 , the impeller of the multiblade blower is provided with a protrusion toward the inner peripheral side while being inclined in the side plate direction on a part of the inner peripheral side edge of the blade. The flow to be separated at the rear of the rotation direction is disturbed and reattaches to the wing. As a result, the generation of separation vortices generated on the rear side in the rotation direction of the blade is suppressed, the turbulence width is reduced, and noise can be reduced. In addition, since the end surface of the blade on the side plate side extends toward the inner peripheral side while inclining so as to protrude from the side plate to the suction port side, a flow rectifying effect in the vicinity of the suction port can be obtained.
[Brief description of the drawings]
FIG. 1 is a side view of a conventional multiblade blower (a casing part and a part of an impeller are cross-sectional views).
FIG. 2 is a side view of the impeller of a conventional multiblade fan (partial cross section shown).
FIG. 3 is a plan view of an impeller of a conventional multiblade fan.
FIG. 4 is a cross-sectional view taken along a line DD showing a conventional impeller, illustrating a noise generation mechanism.
FIG. 5 is a side view of the multiblade fan of the first embodiment (a casing part and a part of an impeller are cross-sectional views).
FIG. 6 is a side view of the impeller of the multiblade blower of the first embodiment (partial cross section shown).
FIG. 7 is a plan view of an impeller of the multiblade fan according to the first embodiment.
FIG. 8A is a view taken along the arrow Z in FIG. 6;
(B) The figure which shows only the wing | blade of the AA cross section of FIG.
(C) The figure which shows only the wing | blade of the BB cross section of FIG.
(D) The figure which shows only the wing | blade of CC cross section of FIG.
FIG. 9 is a view showing the shape of a part of a mold of an impeller according to the first embodiment.
FIG. 10 is a view for explaining molding by the mold of the impeller according to the first embodiment.
FIG. 11 is a cross-sectional view taken along the line CC of the impeller according to the first embodiment, illustrating a noise generation mechanism.
FIG. 12 is a side view of the impeller of the multiblade fan of the second embodiment (partial cross section shown).
[Explanation of symbols]
10, 40 Multiblade blower 11 Casing 11a Air outlet 11b Air inlet 12 Bell mouth 13, 43, 73 Impeller 14 Motor (drive means)
31, 61, 91 Main plate 32, 62, 92 Side plate 33, 63, 93 Wing 71, 72 Mold

Claims (3)

A main plate ( 91 ) that rotates about the rotation axis ( OO ), and a plurality of blades that are arranged in an annular shape about the rotation axis (OO), each having one end fixed to the main plate ( 91 ) and (93), and a side plate of the annular connecting the other end of said plurality of blades (93) (92), at least one of said plurality of blades (93), a part of the inner peripheral edge An impeller (73) having protrusions ( 94a, 95a ) toward the inner peripheral side while inclining in the side plate direction ,
Drive means (14) for rotating the main plate (91);
The suction port (11b) facing the opening on the inner peripheral side of the side plate (92) and the gas provided in the direction substantially orthogonal to the rotary shaft (OO) provided on the outer peripheral side of the impeller (73). A casing (11) having a blowout opening (11a) for delivering and covering the impeller (73);
With
The end face of the wing on the side plate side extends to the inner peripheral side while inclining so as to protrude beyond the side plate toward the suction port side,
Multi-blade blower . The wing (93) has a chord length (L1, L2, L3) that decreases stepwise from one end of the wing ( 93 ) to the other end.
The multiblade fan according to claim 1 . The chord length of the other end (L3) is less 0.85 times the chord length of the end (L1), the multi-blade fan according to claim 2.

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