JP3092554B2 - Centrifugal blower, method for manufacturing the same, and air conditioner equipped with the centrifugal blower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal blower having a wing structure, a method for manufacturing the same, and an air conditioner provided with the centrifugal blower.

[0002]

2. Description of the Related Art Generally, a centrifugal blower has a hub mounted on a rotating shaft of a motor, a shroud opposed to the hub at a predetermined interval, an outer peripheral portion of the hub, and an outer peripheral portion of the shroud. And a plurality of blades arranged substantially radially around the axis of the hub, and air flowing from the leading edge side to the trailing edge side of the blades by the rotation of the impeller. It is configured to generate a flow.

[0003] Further, in such a centrifugal blower, a suction port is provided at an axial portion of the impeller, and air sucked from the suction port is supplied to a periphery of the impeller from an air outlet provided at an outer peripheral portion of the impeller. The form of the suction and the blow of the air is such that the air required for the indoor unit of the air conditioner, particularly the indoor unit of the ceiling embedded type or the ceiling suspended type arranged on the ceiling of the room. A centrifugal blower is often used as a blower for an indoor unit because it matches the circulation form (that is, the form in which room air is sucked in from the center of the room, air-conditioned and then blown out to the entire area of the room).

[0004]

However, in a centrifugal blower, the pressure difference between the pressure surface and the negative pressure surface of the blade performing the blowing work is larger than that of another type of blower such as an axial blower. Big. For this reason, with the rotation of the impeller,
A high-pressure airflow flowing from the leading edge to the trailing edge on the pressure surface side of the blade and a low-pressure airflow flowing from the leading edge to the trailing edge on the suction surface side merge at the trailing edge side of the blade. When the pressure is balanced to the predetermined pressure, the pressure gradient at the trailing edge portion is large, and the velocity loss is large accordingly. In addition, since the trailing edge of the blade in the conventional general centrifugal blower has a shape extending linearly in the blade width direction, the above-described velocity defect occurs simultaneously in the entire region of the trailing edge of the blade. As a result, the turbulence of the air flow in the trailing edge portion of the wing becomes large, and a relatively large blowing noise is generated. Therefore, in the centrifugal blower, there is a strong demand for its silence, and although various solutions have been conventionally proposed, sufficient results have not yet been obtained. Such a demand for silencing is particularly strong in an indoor unit of an air conditioner that includes a centrifugal blower for blowing air-conditioned air and is disposed indoors.

Accordingly, the present invention provides a centrifugal blower capable of reducing blowing noise with a simple and inexpensive configuration, a silent air conditioner equipped with the centrifugal blower, and suitable manufacturing of the centrifugal blower. It is intended to propose a method.

[0006]

Means for Solving the Problems In the present invention, the following configuration is adopted as specific means for solving such problems.

In the first aspect of the present invention, the hub 11 is mounted on the rotating shaft 19a of the motor 19, and is opposed to the hub 11 at a predetermined interval. The formed shroud 12 and a plurality of blades 13, 13, 13, 13, which straddle between the outer peripheral portion of the hub 11 and the outer peripheral portion of the shroud 12 and are arranged substantially radially about the axis of the hub 11. A centrifugal blower configured to generate an airflow flowing from the leading edge 13a side to the trailing edge 13a side of the wing 13 by rotation of the impeller 10;
Edge 13b after, with a saw tooth profile 20 extending in the spanwise direction while bent alternately in spanwise, said saw teeth
A plurality of teeth (21), (21),.
・ If the tooth height is “H” and the tooth pitch is “S”
The outer diameter “D” of the impeller (10)
05 <(H / D) <0.015 "and" 0.01 <S /
D <0.02 ” .

According to a second aspect of the present invention, in the centrifugal blower according to the first aspect, each of the plurality of teeth 21, 21,... Constituting the saw tooth shape 20 is substantially triangular. And

According to a third aspect of the present invention, in the centrifugal blower according to the second aspect, the teeth 21, 21,...
Is characterized in that the front end portion is flat or arc-shaped.

In the fourth aspect of the present invention, the hub 11, the shroud 12 opposed to the hub 11 at a predetermined interval, the outer peripheral portion of the hub 11, and the shroud 12
A plurality of blades 13, 13,... Having a saw-tooth shape 20 which is arranged so as to straddle with the outer peripheral portion and has a trailing edge 13b extending in the blade width direction while alternately bending in the blade length direction.・
When manufacturing the impeller 10 in the centrifugal blower provided with the impeller 10 comprising: a first molding die for molding one of the two side surfaces in the thickness direction of the hub 11 to which the blade 13 is attached. 31, a second molding die 32 which is disposed so as to be relatively close to and detachable from the first molding die 31 and forms the other side surface of the hub 11, and the wings 13, 13,.
A plurality of third molding dies 33, 33, 33, 33, which are arranged in each of the gap portions so as to be able to advance and retreat in the wing length direction of the wing 13 and form at least the saw-tooth shape 20 provided at the trailing edge 13 b of the wing 13 .. Are used to set the first molding die 31, the second molding die 32, and the third molding dies 33, 33,.
The molten material is injected into the cavity formed between the first, second, third, third, third,.
The mold 31 and the second mold 32 are separated from each other to remove the mold, and the above-mentioned third molds 33, 33,.
Are moved in the wing length direction of the wing 13 to remove the mold, thereby producing an integrally formed body 15 in which the hub 11 and the wings 13, 13,... Are integrated. The molded body 15 is characterized in that the impeller 10 is obtained by joining and fixing the shroud 12 formed separately from the integrally formed body 15 to the ends of the wings 13, 13,.

According to a fifth aspect of the present invention, there is provided an air conditioner in which a heat exchanger 5 and a centrifugal blower X are arranged in a ventilation path 4 formed in a casing 1, wherein the centrifugal blower X is provided. , 2 or 3, characterized in that it is a centrifugal blower.

[0012]

According to the present invention, the following effects can be obtained by adopting such a configuration.

According to the centrifugal blower according to the first invention of the present application, the trailing edge 13b of the blade 13 has the saw-tooth shape 20 extending in the blade width direction while alternately bending in the blade length direction. In the trailing edge 13b portion, a long blade portion and a short blade portion are alternately present. Therefore, the trailing edge 13b portion of the airflow flowing on the pressure surface side and the airflow flowing on the suction surface side of the blade 13 is described. At the trailing edge 13b
Is performed gradually in the entire length of As a result, as compared with the conventional case where the trailing edge 13b of the blade 13 is made linear and the merging of the air flows occurs simultaneously, the air flow accompanying the merging of the air flow at the trailing edge 13b is The pressure gradient and the speed loss are reduced, and the turbulence of the air flow at the trailing edge 13b is suppressed accordingly, so that the blowing noise is reduced. That is, the trailing edge 13b of the wing 13 has a sawtooth shape 2
With a simple and inexpensive configuration of 0, the noise of the centrifugal blower can be easily reduced.

In this case, when a plurality of teeth 21, 21,... Constituting the saw-tooth shape 20 have a tooth height “H” and a tooth pitch “S”, the impeller 10
0.005 <(H / D) <0.
015 "and" 0.01 <S / D <0.02 ", the blower noise can be reduced more efficiently, and the noise reduction of the centrifugal blower is further promoted. It is.

According to the centrifugal blower according to the second invention of the present application, in addition to the effects described above, each of the plurality of teeth 21, 21,... By doing so, the structure of the molding die is simpler than, for example, a case where this is made into a complicated polygonal shape, and there is a specific effect that the manufacturing cost of the centrifugal blower can be reduced accordingly.

According to the centrifugal blower according to the third invention of the present application, in addition to the effects described above, the tips of the triangular teeth 21, 21,... Have a flat or arc shape. Thus, the tip is less likely to be damaged by a crack or the like than in a case where the tip is sharp at an acute angle, for example, and the durability of the centrifugal blower is improved accordingly.

The method for manufacturing a centrifugal blower according to the fourth invention of the present application is characterized in that the hub 11 constituting the impeller 10 is provided.
And the wings 13 are integrated into a first molding die for molding one of the two side surfaces of the hub 11 in the thickness direction on which the wings 13 are attached. 31
And a second molding die 3 which is disposed so as to be relatively close to and detachable from the first molding die 31 and forms the other side surface of the hub 11.
., The saw-tooth shape 2 provided at at least the trailing edge 13b of the wing 13 so as to be able to advance and retreat in the wing length direction of the wing 13 in each of the gaps between the wings 13, 13,.
It is manufactured by using a plurality of third molding dies 33, 33,.

Therefore, by using the third molding dies 33, 33,...
For example, a molding die (for example, the first molding die and the second
According to the manufacturing method using only the molding die, it is not possible to remove the die (that is, the teeth 21 are arranged in a direction orthogonal to the direction of the die).
The molding of the saw-tooth shape 20 has been impossible because of the extension of the saw-tooth shape 20.
The saw-tooth shape 20 can be easily formed by setting the direction in which the molding dies 33, 33,. For this reason, for example, after forming the hub 11 and the wings 13, 13,... Separately, and then combining the hub 11 and the wings 13, 13,. , And thus the impeller 10 can be easily manufactured, and as a result, a centrifugal blower can be provided at lower cost.

According to the air conditioner of the fifth invention of the present application, the air conditioner is used as a blower for conditioned air.
Since the centrifugal blower described in (1) is provided, an effect peculiar to the centrifugal blower, that is, high quieting performance is directly reflected in the operation performance of the air conditioner, and an air conditioner with higher silent performance is provided. This effect is particularly remarkable when the air conditioner is an indoor unit installed indoors.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a centrifugal blower according to the present invention, a method for manufacturing the same, and an air conditioner equipped with the centrifugal blower will be specifically described based on preferred embodiments shown in the accompanying drawings.

FIG. 1 shows a centrifugal blower X according to an embodiment of the present invention. FIG. 2 shows an indoor unit Z of an air conditioner including the centrifugal blower X.

As shown in FIGS. 1 and 2, the centrifugal blower X includes a motor 19 and an impeller 10 driven to rotate by the motor 19. The impeller 10
A shroud 12 which is axially mounted on a motor shaft 19a of the motor 19, is opposed to the hub 11 at a predetermined interval, and has a blower inlet 16 formed at an axial center thereof; And a plurality of blades 13, 13, ... straddling between an outer peripheral portion of the shroud 12 and an outer peripheral portion of the shroud 12 and radially arranged at equal intervals in a circumferential direction. The impeller 10 is connected to the hub 1
1 and the outer periphery of the shroud 12 are connected to a blower outlet 17.
The passage from the blower inlet 16 to the blower outlet 17 is an air flow path 18.

The hub 11 is formed by depressing the vicinity of the axis of a disk body having a predetermined diameter in the thickness direction. As will be described later, the hub 11 is made of resin together with the following wings 13, 13,. It is integrally formed by material molding.

The shroud 12 is an annular body having an arc-shaped cross section, and is formed separately from the hub 11 and the like by molding a resin material. And this shroud 12
After the molding, the hub 11 and the following wings 13, 1
Are joined and fixed to an integrally formed body 15 formed integrally with the members 3.

The wing 13 is a plate having a curved streamlined cross-sectional shape, and, as described above, straddles between the outer peripheral portion of the hub 11 and the outer peripheral portion of the shroud 12 and A plurality of (eight in this embodiment) are arranged radially at equal intervals in the circumferential direction, and are integrally formed with the hub 11 by molding a resin material.

The wing 13 has the greatest feature in the structure of the trailing edge 13b. That is, as shown in FIGS. 1 to 4, the wing 13 of this embodiment does not have a trailing edge 13 b formed in a straight line as in the related art, but alternately bends in the wing length direction and in the wing width direction. The saw tooth shape 20 extends. The saw-tooth shape 20 corresponds to the trailing edge 13.
., the teeth 21 are continuous along the line b. In this embodiment , as shown in FIG. 3 and FIG. When the tooth height of the tooth 21 is "H" and the tooth pitch is "S" in the relationship between the tooth 21 and the outer diameter "D" of the impeller 10 in addition to the substantially trapezoidal shape. , "0.005
<(H / D) <0.015 "and" 0.01 <S / D <
0.02 ".

Here, a method of manufacturing the impeller 10 (ie, a method of manufacturing the centrifugal blower X) will be described.

As described above, the impeller 10 has a hub 11, a shroud 12, and a plurality of blades 1 as its constituent members.
The hub 11 and each of the wings 13, 1
Are molded integrally (integrally molded body 15), while the shroud 12 is used to mold the integrally molded body 1
5, and is obtained by joining (for example, welding or bonding) the shroud 12 to the integral molded body 15 after molding these members, and integrating them. Such a manufacturing procedure is well known in the art.

However, in the conventional centrifugal blower, since the trailing edge 13b of the blade 13 has a linear shape, when the integrated molded body 15 is molded, the integral molded body 15 is disposed so as to face each other and contact each other in the facing direction. The blade 13 of this embodiment can be easily obtained by using a pair of molds (for example, a lower mold and an upper mold) that can be separated. , And the above-mentioned hub 11 are integrated with each other to form the integral molded body 15 using the pair of molding dies as described above. This is not possible due to the relationship with the stamping of the part.

Therefore, in this embodiment, the manufacturing method of the present invention is applied to the molding of the integrated molded body 15,
The following three types of molds (that is, the lower mold 31 and the upper mold 32)
And a plurality of punching dies 33, 33,...).

As shown in FIGS. 5 and 6, the lower mold 31 is formed with a hub inner surface forming surface 31a for forming the surfaces of the integrally formed body 15 on the 13, 13,... A wing forming surface 31b for forming the edge 13a side and a die 3 to be described below.
And a pull-out fitting portion 31c that secures a fitting space for the third die.
Corresponds to.

The upper die 32 is a molding die provided with a hub outer surface molding surface 32a for molding a surface of the integrally molded body 15 on which the wings 13, 13,... Are not arranged. Corresponds to the “second molding die”.

The blanking die 33 is disposed between the respective 13, 13,... Of the integrally formed body 15 to form the saw-tooth shape 20 and the saw blade forming surface 33a.
And a wing forming surface 33b for forming a portion on the side of the trailing edge 13b, the "third forming die" in claims.
Corresponds to.

Then, the hub inner surface forming surface 3 of the lower die 31 is formed.
The upper die 32 is placed on the upper side of the upper die 1a, and the hub outer surface forming surface 3
2a is arranged in a posture oriented toward the lower mold 31 so that the upper mold 32 can be moved toward and away from the lower mold 31 in a direction opposite to the lower mold 31, while each of the removal dies 33, 33,. Each of these is formed between the lower die 31 and the upper die 32 in a direction orthogonal to the direction in which the lower die 31 and the upper die 32 face each other, and each of the unmolded dies 33, 33,. It is arranged so as to be located between the respective wings 13 in the molded body 15. Thus, each of the molding dies 31, 3
By arranging 2, 33, 33,..., A cavity for molding the integrated molded body 15 is formed therebetween. Therefore, by injecting the molten resin material into the cavity, the above-mentioned integrally formed body 15 is formed.

After the injection of the resin material and the completion of the molding, the molding dies 31, 32, 33, 33,. In this case, the upper mold 32 is removed by moving the upper mold 32 in a direction in which the lower mold 31 is separated. Also,
Each of the dies 13 is laterally moved along the blade length direction of the wing 13 to perform the dies. By such a molding method, the above-mentioned integrally molded body 15 can
The integrated molded body 15 can be easily formed by molding in spite of the configuration in which the trailing edge 13b is provided with the saw-tooth shape 20 on the rear edge 13b. After the molding of the integrally molded body 15, the respective 13, 13,.
The impeller 10 is obtained by joining and fixing the shroud 12 to an end of the impeller.

In the centrifugal blower X manufactured as described above, the trailing edge 13b of each of the blades 13, 13,... When air is blown by rotating the impeller 10, the blowing sound is of a conventional structure (ie, the blade 13
(In which the trailing edge 13b is linear), and high noise reduction performance can be obtained.

That is, by forming the trailing edge 13b of the wing 13 into the saw-tooth shape 20, a portion having a long blade length and a short portion are alternately present at the trailing edge 13b.
For this reason, the merging of the airflow flowing on the pressure surface side and the airflow flowing on the suction surface side of the blade 13 at the trailing edge 13b is gradually performed stepwise over the entire length of the trailing edge 13b. As a result, the pressure gradient and the velocity loss of the air flow due to the merging of the air flows at the trailing edge 13b are reduced, and the turbulence of the air flow at the trailing edge 13b is suppressed, thereby reducing the blowing noise. It is.

Also, as in this embodiment, the size of each tooth 21, 21,... In the sawtooth shape 20 is set in relation to the outer diameter “D” of the impeller 10. When the height is “H” and the tooth pitch is “S”, “0.0”
05 <(H / D) <0.015 "and" 0.01 <S /
By setting D <0.02 ”, the blowing noise can be more efficiently reduced, and the noise reduction of the centrifugal blower is further promoted.

On the other hand, as shown in FIG. 2, in the indoor unit Z provided with the centrifugal blower X having the above-described structure, the effect unique to the centrifugal blower Z, that is, the high static The performance is directly reflected on the operation performance of the indoor unit Z, and as a result, the indoor unit Z with higher silent performance can be provided by employing the centrifugal blower X.

The structure of the indoor unit Z will be briefly described as follows. That is, the indoor unit Z is configured by disposing the centrifugal blower X in the center of the ventilation path 4 in the casing 1 and disposing the heat exchanger 5 around the centrifugal blower X. In the figure, reference numeral 2 denotes a suction port corresponding to the blower suction port 16 of the centrifugal blower X, and a bell mouth 8 is disposed in the suction port 2 and a bell mouth 8 is provided below the bell mouth 8. A suction grill 6 having a filter 7 is mounted. An outlet 3 is formed on the outer peripheral side of the suction grill 6 so as to face the downstream side of the heat exchanger 5.

In the indoor unit Z, by operating the centrifugal blower X, the room air sucked from the suction port 2 is blown out from the blower outlet 17 of the centrifugal blower X toward the heat exchanger 5. . The blown air exchanges heat with the refrigerant circulating on the side of the heat exchanger 5 while passing through the heat exchanger 5 and is blown into the room from the outlet 3 as warm air or cold air. Heat or cool.

[Brief description of the drawings]

FIG. 1 is a perspective view of a centrifugal blower according to the present invention.

FIG. 2 is a cross-sectional view of an indoor unit of an air conditioner including the centrifugal blower shown in FIG.

FIG. 3 is an enlarged view of an edge of a blade of the centrifugal blower shown in FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is an explanatory view of a manufacturing method of the impeller by molding.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5;

[Explanation of symbols]

1 is a casing, 2 is a suction port, 3 is an outlet, 4 is a ventilation path, 5 is a heat exchanger, 6 is a suction grill, 7 is a filter,
8 is a bell mouth, 9 is a ceiling, 10 is an impeller, 11 is a hub, 12 is a shroud, 13 is a wing, 14 is a boss, 15 is an integrally molded body, 16 is a blower inlet, 17 is a blower outlet, 18 is a blower outlet. An air flow path, 19 is a motor, 20 is a saw-tooth shape, 21 is a tooth, 22 is a blade joining surface, 31 is a lower mold (first molding mold), 32 is an upper mold (second molding mold), and 33 is a blanking mold ( X is a centrifugal blower, and Z is an indoor unit (air conditioner).

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F04D 29/30 F04D 29/28

Claims (5)

(57) [Claims] 1. A hub (11) which is axially mounted on a rotating shaft (19a) of a motor (19), and which is arranged to face the hub (11) at a predetermined interval and has a suction port formed in its axial center. A shroud (12) formed with (16) and an outer peripheral portion of the hub (11) and an outer peripheral portion of the shroud (12) are straddled and substantially radially centered on the axis of the hub (11). Wings (13), (1)
3) An impeller (10) comprising: a leading edge (13a) of the wing (13) by rotation of the impeller (10).
A centrifugal blower configured to generate an airflow flowing from the side to the trailing edge (13a) side, wherein the trailing edge (13b) of the blade (13) is alternately bent in the blade length direction to form the blade. to a saw tooth shape extending in the width direction (20)
And a plurality of teeth constituting the saw-tooth shape (20).
(21), (21),.
When the switch is set to "S", the outer diameter of the impeller (10)
“0.005 <(H / D) <0.01 with respect to“ D ”
5 "and" 0.01 <S / D <0.02 " . 2. The plurality of teeth (21) constituting the saw-tooth shape (20) according to claim 1,
(21) A centrifugal blower characterized in that each of them has a substantially triangular shape. 3. The centrifugal blower according to claim 2, wherein each of the teeth (21), (21),... Has a flat or arc-shaped tip. 4. A hub (11) and a shroud (12) which is arranged to face the hub (11) at a predetermined interval.
And the outer peripheral portion of the hub (11) and the shroud (12)
And a plurality of blades (20) having a saw-tooth shape (20) which is arranged so as to straddle the outer peripheral portion of the blade and has a trailing edge (13b) extending in the blade width direction while being alternately bent in the blade length direction. 1
When manufacturing the impeller (10) in the centrifugal blower provided with the impeller (10) composed of 3), (13),..., The blades on both sides in the thickness direction of the hub (11) (1
A first molding die (3) for molding one side surface to which the 3) is attached.
1), a second molding die (32) that is disposed so as to be relatively close to and detachable from the first molding die (31) and that molds the other side surface of the hub (11); ), (13),..., The saw-tooth shape provided at at least the trailing edge (13b) of the wing (13) so as to be able to advance and retreat in the wing length direction of the wing (13). 20) to form a plurality of third molds (3
3), (33),..., And the first molding die (31), the second molding die (32), and the third molding dies (33), (33),. It is set at a predetermined assembly position, and each of these molds (31), (3)
2), (33), (33),..., And the molten material is injected into the cavity formed between the first and second molding dies (31) and (3).
2) are separated from each other to remove the mold, and each of the third molding dies (33), (33),... Is moved in the blade length direction of the wing (13) to remove the mold. To produce an integrally formed body (15) in which the hub (11) and the wings (13), (13),... Are integrated, and thereafter, the wings (15) in the integrally formed body (15) are manufactured. 1
3), (13), .. at the end of the integral molded body (15)
A method for manufacturing a centrifugal blower, wherein the impeller (10) is obtained by joining and fixing the shroud (12) formed separately from the shroud (12). 5. An air conditioner comprising a heat exchanger (5) and a centrifugal blower (X) arranged in a ventilation path (4) formed in a casing (1), wherein the centrifugal blower (X) is provided. An air conditioner, wherein X) is the centrifugal blower according to claim 1, 2, or 3.