JP2940751B2 - Multi-wing 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 multi-blade blower, and more particularly, to a multi-blade blower suitable for use in an air conditioner mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, a multi-blade fan used for an air conditioner or the like has a multi-blade fan having a large number of blades as disclosed in JP-A-2-146298 and JP-A-2-151519. It is housed in a case with a bellmouth. Multi-wing fans
The structure is such that a number of blades are arranged between the bottom plate and the retaining ring. These conventional techniques disclose techniques for preventing a backflow of a flow flowing from an inlet of a blade in a multi-blade blower.

[0003]

[0004]

The multi-blade fan
The wind speed distribution of the air blown out from the
Because the air is uneven on the side opposite to the air intake,
Case for accommodating multi-blade fans due to uneven speed distribution
The wind pressure (pressure) distribution in the interior also becomes non-uniform. Accordingly
When the unevenness of the wind speed distribution becomes large,
Loss due to eddy currents and backflow
Fan efficiency is reduced and noise is generated.

[0005]

[0006]

[0007] In view of the above, the present invention provides a multi-blade fan.
By making the wind speed distribution of the blown air uniform,
The purpose is to improve noise efficiency and reduce noise
You.

[0008]

According to the present invention, there is provided a case having a bell mouth forming an air intake, and a plurality of blades housed in the case and arranged in a circumferential direction. A centrifugal multi-blade fan having an annular shroud formed at an air suction side end of the plurality of blades and a bottom plate formed at a counter air suction side end of the number of blades, wherein the shroud is It is formed in a substantially arc-shaped cross-sectional shape along the air flow that flows from the air inlet between the blades in the direction of the fan diameter outside from the fan axis direction, and the inner wall cross-sectional shape of the case near the bell mouth is formed. The blade is formed so as to follow the cross-sectional shape of the shroud via a minute gap between the shroud and the blade.
Over the air inlet to the site opposite the air intake
And the case is opposite to the air intake.
On the other side, the radially outward side of the centrifugal multi-blade fan
It extends toward the side opposite to the air intake and tilts
It is characterized in that an inclined portion is formed .

[0009]

[0010]

[0011]

First, the blade (25) is connected to the air inlet (3).
6) From the side, beyond the bottom plate (24), the air intake (3)
6), the blade (2)
The air blown out from 5) is the air intake of the blade (25).
From the mouth (36) end to the air intake (36) opposite end
Distributed in the range up to the site. Therefore, in the present invention,
Raid (25) is the bottom plate from the air inlet (36) side
(24) Compared to a centrifugal multi-blade fan that does not extend beyond
And the wind speed of the air blown out of the centrifugal multi-blade fan (20)
The point of the cloth where the wind speed is maximum is the opposite of the air intake (36).
Moving to the other side and the maximum wind speed
Then, the wind speed of the air blown out from the centrifugal multi-blade fan (20)
The cloth becomes uniform. Therefore, in the present invention, the wind speed distribution
Vortex and backflow in the case (22) due to unevenness of
To improve fan efficiency and reduce noise.
Can be Second, the air collection of the case (22)
On the opposite side of the inlet (36), a centrifugal multi-blade fan
The air inlet (36) is closer to the outside of the diameter of (20).
An inclined portion (54) is formed extending toward the opposite side and inclined.
Of the centrifugal multi-blade fan (20)
(54) Air blown out from the vicinity (hereinafter this air
This is called the rate side outlet flow. ) Is tilted by the Coanda effect
Circulates along the part (54) and blows out on the plate side
Accelerate the blown air near the flow. Therefore, the plate
Can increase the wind speed of the blown air near the side blowout
Therefore, the wind of air blown out from the centrifugal multi-blade fan (20)
The speed distribution can be made more uniform. In the end,
Improve fan efficiency and reduce noise
it can.

[0012]

REFERENCE EXAMPLE Before describing an embodiment of the present invention, the embodiment of the present invention will be described.
A reference example serving as a premise of the embodiment will be described. Below, reference
An example will be described with reference to the drawings. A first reference example will be described using a blower that takes in air from a vehicle air conditioner as an example .

As shown in FIG. 2, the ventilation system supplies the air taken in from the outside air intake 2 for taking in the air outside the vehicle compartment or the inside air intake 3 for taking in the air inside the vehicle compartment from the air intake 36 of the blower 6. It is taken into the case 1 and guided to the evaporator 7 by the centrifugal multi-blade fan 20. The outside air inlet 2 and the inside air inlet 3 are opened and closed by a rotatable damper 5. An air mix damper 8 is provided on the outlet side of the evaporator 7, and a second flow path 18 on one side of the first flow path 18 and the second flow path 19 partitioned by the air mix damper 8 is provided.
The heater core 17 is attached to the flow path 19. The air mix chamber 9 formed on the outlet side of the air mix damper 8 and the heater core 17 includes a defroster outlet 13,
It communicates with the chest outlet 12 and the foot outlet 10. Dampers 14, 15, 16 for adjusting the opening degree of the outlets are rotatably attached to the inlet side of each of the outlets 10, 12, 13.

The specific structure of the blower 6 is shown in FIG.
Is shown in The blower 6 includes a centrifugal multi-blade fan 20 and a case 22. Here, the case 22 is formed by integrally assembling a resin-molded upper case 22a and a lower case 22b with a clamp, a screw or the like, is formed in a well-known scroll shape, and extends in a radially outward direction. 2 and is connected to the air inlet side of the evaporator 7.

A fan driving motor 33 shown in FIG. 2 is fixed to the lower case 22b of the case 22. The centrifugal multi-blade fan 20 includes a bottom plate 24, a number of blades 25, and a shroud 26 formed in an annular shape on the top of the blade 25 and serving as a reinforcing ring. The bottom plate 24 is provided with a motor 33 for driving the fan shown in FIG.
Boss portion 28 to which the driving force is transmitted. The top surface 24a of the bottom plate 24 is formed into a curved surface that smoothly curves from the center to the outer periphery. The blades 25 are formed so as to rise from the vicinity of the outer peripheral end 24b of the bottom plate 24, and are arranged in the vicinity of the outer peripheral end 24b of the bottom plate 24 at a predetermined arc interval along the circumferential direction. . Shroud 26 is blade 2
5, the line connecting the inner peripheral end 26a of the shroud and the outer peripheral end 24b of the bottom plate coincides with the parting line. For this reason, a centrifugal fan with a sufficiently long shroud
The fan 6 can be formed by simple upper and lower mold splitting.
Further, the upwardly from the shroud inner peripheral edge 26a Ru Tei formed annular projection 26b is.

The case 22 accommodating the centrifugal multi-blade fan 20 is formed with a bell mouth 31 having a semicircular cross section so as to enclose the projection 26b of the shroud 26, and the bell mouth inner wall 31a and the projection 26b There is a small constant interval δ between them, for example, about 3 mm. The inner wall 22c of the case near the base of the bell mouth 31 is at a substantially constant minute interval δ, for example, about 3 m from the top surface 26c of the shroud 26.
They are formed at intervals of about m. Such a substantially constant minute interval δ is such that the top surface 2 which is smoothly curved from the outer peripheral wall of the projection 26 b of the shroud 26 toward the radially outward direction is formed.
6c to the radially outer end 26d.

According to the first embodiment , the air intake 36
The shroud 26 is formed into a substantially arc-shaped cross-sectional shape so as to change the air flow taken in from the fan axial direction to the fan radial outside direction. Since it is formed narrow by δ and over a long distance from the inner diameter side to the outer diameter side, the amount of air flowing backward from the outlet of the blade 25 to the inner diameter side through this gap is reduced.
Therefore, it is possible to improve fan efficiency and reduce noise.

According to the experimental data of the present inventor, the first
With the configuration of the reference example , it was found that the fan efficiency was improved by about 3% and the noise was reduced by about 1.5 dBA compared with the conventional example.

Next, the first reference example of the present invention and a conventional comparative example will be described with reference to FIGS. 3 (A) and 3 (B). Backflow Prevention Effect In the first reference example shown in FIG. 3A, an air flow is formed from the air intake 36 of the bell mouth 31 in the direction of the arrow,
The air flow direction is gradually changed from the fan axial direction to the fan radial outward direction, and a flow is formed from the outer end of the blade 25 in the direction of the arrow. At this time, since the bellmouth inner wall 31a, the case inner wall 22c, and the shroud 26 are kept in a narrow gap over a long area, backflow flowing through this gap hardly occurs. In contrast, FIG.
In the conventional comparative example shown in (B), the area of the narrow gap between the tip 42b of the reinforcing ring 42 and the case 43a is very short, and the backflow 101 flowing through this gap cannot be completely eliminated. This backflow causes a reduction in fan efficiency and an increase in noise.

The effect of preventing eddy currents between the blades The wind speed distribution at the outlet of the blade 25 is biased to the lower side of the blade 25 as shown in FIG. Yes, blade 2
There is almost no air flow above 5. For this reason, when the ventilation resistance is slightly increased, a vortex 102 and a backflow 103 are generated in the comparative example of FIG. On the other hand, in the first reference example shown in FIG. 3A, since the shroud 26 is provided, no eddy current or backflow occurs between the blades 25, so that the fan efficiency can be improved and the noise can be effectively reduced. .

The effect of preventing eddy currents at the upper portion of the scroll The multi-blade blowers of the first reference example and the comparative example are blowers applied to a ventilation system of an air conditioner for a vehicle. Is relatively large. Therefore, in the comparative example shown in FIG.
Due to the extra space 38 inside the scroll above the position of, a vortex 104 is generated, which tends to cause a reduction in fan efficiency and an increase in noise. In contrast, FIG.
In the first reference example shown in (A), since the extra space on the radially outer side of the blade 25 is formed narrow,
Whirlpools and backflows are less likely to occur, improving fan efficiency and effectively reducing noise.

In the first embodiment , the above-mentioned effect is obtained when the present invention is applied to a multi-blade blower in general. Particularly, when applied to a ventilation system having a relatively large ventilation resistance, such as a ventilation system for an air conditioner, The effect is remarkable.

Next, experimental data will be shown. The experimental conditions were as follows: fan diameter: 150 mm, fan width: 85 mm, scroll divergence angle: 5.5 °, blower motor voltage: 12 V (constant), gap between shroud and case / fan outer diameter: 0.
02. As a result, the relationship between the flow coefficient Φ, the specific noise K _S and the pressure coefficient ψ was as shown in FIG. It can be seen that, in the first reference example , the specific noise K _S is relatively low and the pressure coefficient ψ is relatively large in the first reference example as compared with the comparative example.

Next, an experiment was conducted on how the minimum specific noise K _S and the fan efficiency were changed by changing the ratio of the gap between the shroud and the case / the fan outer diameter. Here, the minimum specific noise K _S refers to a value at which the specific noise when the flow coefficient is changed is minimized. The result is shown in FIG. FIG.
It was found from the results shown in that the value of the minimum specific noise K _S was significantly reduced when the ratio of the clearance / fan outer diameter was 0.05 or less.

FIG. 10 shows the relationship between the flow coefficient φ, the specific noise Ks, and the pressure coefficient と き when the tip position of the bell mouth 31 is changed. As shown in the shape of the bell mouth 31 in FIG. 10, the positions A0 and A1 are respectively the clearance 1 between the tip of the bell mouth 31 and the fan blade / the fan outer diameter D.
Are specifically 0.02 and 0.04, and specifically, the gap l at the position A0 is 3 mm, and the gap l at the position A1 is 6 mm. Position A2 is shroud inner peripheral end 2
6A, the position A3 is at the same height as the protrusion 26b (B0) of the shroud 26. Thus, as a result of an experiment in which the tip position of the bell mouth 31 was changed with respect to the projection 31, it was found that the noise was lowest at the position A0. From this experimental result, it is presumed that providing the tip of the bell mouth 31 on a substantially extended line of the arc of the shroud 26 smoothens the flow of air and reduces noise.

Next, the height of the projection 26b of the shroud 26 was examined. The result is shown in FIG. As shown in the shape of the protrusion 26b in FIG.
No. 2 is when the ratio of the height (= h) of the protrusion 26b / the fan outer diameter D is 0.06, 0.03, 0, and specifically, the height h at the height B0 is The height h at the time of 9 mm and the height B1 is 4.5 mm. As a result of this experiment, it was found that the noise was lowest when the height was B0. From this experimental result, if the distance between the protrusion 26b and the inner wall 31a of the bell mouth is set to a very small value, the backflow can be prevented, so that noise can be reduced. Note that the above-described experiments whose experimental results are shown in FIGS. 4 and 5 use a combination of a bell mouth A0 and a shroud B0.

Next , examples of a multi-blade blower according to another reference example are shown in FIGS. Second reference example shown in FIG. 6, the first ginseng
This is an example in which the protrusion 26b shown in the example is not formed. A space in which the gap between the top surface 26c of the shroud 26 and the case inner wall 22c is substantially constant is formed extending in the radial direction.

A third reference example shown in FIG.
Is an example in which the outer peripheral end 33a is extended radially outward. An outer peripheral end 33 a of the bottom plate 33 extends to an outer end of the shroud 26. In this case, the bottom plate 33 and the blade 25
Are formed integrally, while the shroud 26 is
Is formed by post-installation.

The fourth reference example shown in FIG.
Is an example of a cut at the inner diameter side. In the fourth reference example , since the bell mouth inner end 31b is cut off halfway, the air intake 36 can be formed large, and thus there is an effect that the amount of air intake can be increased.

The fifth reference example shown in FIG. 9 is an example in which the shape of the shroud is formed in a straight, conical shape. The shroud 35 extends in a conical slope. The case inner wall 22c extends obliquely in a straight line substantially in parallel with a narrow gap corresponding to the shape of the shroud 35.

A sixth reference example shown in FIG.
This is an example in which 4 is inclined in the direction opposite to the shroud 26 side as going outward in the radial direction. Since the air flows in from the axial direction of the fan 20 and flows out in the radial direction, if the bottom plate is inclined in the flow direction of the air, the air flows along the inclination of the bottom plate 24, so that the turbulence of the air flow is reduced. . Therefore, by forming the bottom plate 24 together with the shroud and the bell mouth of the present invention, it is possible to further increase the noise reduction effect.

[0032]

EXAMPLES Next, a description will be given of an embodiment of the present invention. What
For components having the same function as the above reference example,
The same reference numerals are given. FIG. 13 shows an embodiment of the present invention in which the side wall 5 opposite to the air inlet 36 provided in the case 22 is provided.
2 is an annular flat portion 521 corresponding to the fan 20;
And a flow path wall 50 that forms a discharge flow path. The flow path wall 50 includes an inclined flat plate portion 53 and an inclined connecting portion (inclined portion) 5.
4 The inclined flat plate portion 53 is provided substantially orthogonal to the outer peripheral wall on the outer peripheral wall side, and is formed in a spiral shape that gradually enlarges the flow path area of the discharge flow path toward the outlet side of the discharge flow path. The discharge channel is formed so as to be inclined in a direction to enlarge the discharge channel toward the outlet side of the discharge channel. The inclined connecting portion 54 extends toward the side (motor 33 side) opposite to the air intake 36 toward the radially outer side of the fan 20, and is provided to be inclined. Part 53
To the inner peripheral end of Further, the blades 25 extend from the air inlet 36 side to the air inlet 3 beyond the bottom plate 24.
6 (the motor 33 side).

Here, the angle θ of the inclined connecting portion 54
The relationship between _s and the blowing angle θf of the airflow flowing out of the fan 20 will be described. FIG. 14 shows a case 2 used for the fan 20 in which the airflow flowing out of the fan 20 flows out at an angle θf with respect to a horizontal plane perpendicular to the axial direction of the fan.
2 shows an optimum angle θ _s of the inclined connecting portion 54.

The optimum inclination angle is an angle at which the lowest specific noise ks is lowest. It should be noted that the fan efficiency ηf is related to the fact that the lower the specific noise ks, the higher the efficiency.
This in fan efficiency ηf may determine the optimum tilt angle θ _s.

In this experiment, a fan 20 having a different blowing angle θf was formed by changing the diameter of the fan 20 and the height of the blade 25, and an experiment was performed using the fan 20 having a different blowing angle θf. However, the optimum inclination angle θ _s for each fan 20 is θ _s = (θf−5) ° with respect to the angle θf of the airflow flowing out of the fan 20 as shown by hatching in FIG. Θθf °.

As described above, the shape of the inclined side wall 52 is
By forming with the shapes of the shroud and the bell mouth of the present invention, the noise reduction effect can be further enhanced.

Further the shape of the bottom plate 24 of the sixth reference example, the combination of the side wall 52 of the real施例case 22 can be reduced even more noise.

[0038]

According to the present invention, first, the blade is empty.
From the air intake side to the side opposite the air intake beyond the bottom plate
Air that blows out from the blade
Is like a wind speed distribution curve D1 shown in FIG.
From the air inlet end of the blade to the opposite end of the air inlet
Are distributed in the range up to the site. In contrast, FIG.
As shown in (B), the blade extends beyond the bottom plate.
From the air intake side to the bottom plate
And the air blown out of the blade is, of course, the blade
From the air inlet side end to the bottom plate
(See wind speed distribution curve D2). By the way, wind speed distribution curve
Areas S1 and S2 of a portion surrounded by D1 and D2 are
It indicates the volume of air blown from the centrifugal fan.
These areas S1 and S2 are given to the air from the centrifugal multi-blade fan.
The quantity has a positive correlation with the given kinetic energy.
For this reason, the movement energy given to the air from the centrifugal multi-blade fan
If the energies are equal, both areas S1, S2 are equal
Therefore, the vertex of the wind speed distribution curve D1 (the point where the wind speed becomes maximum)
Is opposite to the air intake compared to the top of the wind speed distribution curve D2.
Side, the maximum wind speed decreases. This
In addition, the wind speed distribution range of the wind speed distribution curve D1 is
Since it is larger than the cloth curve D2, the wind speed distribution curve
D1 is more uniform than the wind speed distribution curve D2. But
Thus, in the present invention, the air blown out of the centrifugal multi-blade fan
Since the wind speed distribution can be made uniform, the wind speed distribution
Vortex and backflow of air in case due to unevenness
To improve fan efficiency and reduce noise.
Can be achieved. Second, the air intake of the case
On the side opposite to the radially outward side of the centrifugal multiblade fan.
The inclination that extends toward the opposite side of the air intake and tilts
Since the slope is formed, the centrifugal multi-blade fan
The plate side blow-off flow blown out from the vicinity of the
Fruit flows along the slope, and the plate side
Accelerates the blowing air near the blowing flow. Therefore, play
The wind speed of the blown air near the
Wind velocity distribution of air blown out from the centrifugal multi-blade fan
Can be further uniformized. After all, a fan
Improved efficiency and reduced noise
You.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a right half of a multi-blade blower according to a first reference example .

FIG. 2 is the first reference in which a multi- blade blower is applied to a vehicle air conditioner.
It is a schematic block diagram which shows a consideration example.

FIG. 3A is a schematic configuration diagram illustrating a main part of a multi-blade blower according to a first reference example ; (B) is a schematic configuration diagram showing a main part of a multi-blade blower of a comparative example.

4 is a characteristic diagram of comparing Comparative Example with the first reference example with the flow coefficient and the specific noise and pressure coefficient.

FIG. 5 is a characteristic diagram showing an influence of a ratio between a gap between a shroud and a case and a fan outer diameter on a fan efficiency and a minimum specific noise.

FIG. 6 is a sectional view of a main part showing a second reference example .

FIG. 7 is a sectional view of a main part showing a third reference example .

FIG. 8 is a sectional view of a main part showing a fourth reference example .

FIG. 9 is a sectional view of a main part showing a fifth reference example .

FIG. 10 is a diagram showing characteristics according to a bellmouth shape.

FIG. 11 is a diagram showing characteristics according to the height of a protrusion.

FIG. 12 is a diagram showing a sixth reference example ;

13 is a diagram showing the real施例of the present invention.

FIG. 14 shows an optimum inclination angle θs and a blowing angle θ from a fan.
It is a figure showing relation with f.

FIG. 15 is an explanatory diagram for easily understanding the effects of the present invention.

[Explanation of symbols]

 Reference Signs List 6 multi-blade blower 20 centrifugal multi-blade fan (fan) 22 case 22a upper case (case) 22b lower case (case) 22c case inner wall 24 bottom plate 25 blade 26 shroud 26b protrusion (annular protrusion) 26c top surface 31 bell mouth 36 air Intake

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Teruhiko Kameoka 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside of Denso Corporation (72) Inventor Takahiro Tokunaga 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Nihon Denso Co., Ltd. (72) Inventor Hideo Asano 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (72) Inventor Sugi Hikari 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Nippon Denso Co., Ltd. (56) References JP-A-60-33000 (JP, A) JP-A-56-81297 (JP, A) JP-A-50-49711 (JP, A) JP-A-60-261997 (JP, A) (JP, U) JP 60-10200 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04D 29/28 F04D 29/44

Claims (1)

(57) [Claims] 1. A case having a bell mouth forming an air intake, a plurality of blades housed in the case and arranged in a circumferential direction, and formed at an air suction side end of the plurality of blades. A centrifugal multi-blade fan having an annular shroud and a bottom plate formed at a non-air suction side end of the plurality of blades, wherein the shroud has a fan diameter between the blades from the air intake port in a fan axial direction. It is formed in a substantially arc-shaped cross-sectional shape along the air flow flowing while turning in the outward direction, and the inner wall cross-sectional shape near the bell mouth of the case is the
Of the shroud through a small gap between the shroud and
The blade is formed so as to conform to the cross-sectional shape, and the bottom plate is formed from the air intake side.
Extending to a site opposite to the air intake
And further, of the case on the side opposite to the air intake.
In the part, as it goes to the radial outside of the centrifugal multi-blade fan,
An inclined portion extending toward the side opposite to the air intake and inclined
A multi-blade blower characterized in that a multi-blade fan is formed .