JPH05312194A - Sirocco fan - Google Patents

Abstract

PURPOSE:To restrain generation of vortex in a casing so as to reduce noise, and reduce the loss so as to improve operation efficiency, concerning a sirocco fan used as the blower fan of an air conditioner for automobile and the like. CONSTITUTION:This sirocco fan is provided with a wane wheel 3A constituted by arranging many wanes facing front in the rotational direction and cylindrically, and a casing 1A in which a flow passage 1a is formed in the outer circumference in the radial direction of the vane wheel 3A and the wane wheel 3A is received. The upper wall 11 of the casing 1A is formed with an opening part 12 of nearly same diameter as that, of the vane wheel 3A, and the wane wheel 3A is rotated in the casing 1A. Hereby, inflow air sucked from the opening part 12 is fed to the outside of the casing 1A through the flow passage 1a. In the such constituted fan, the lower wall 10 of the casing 1A is formed to be inclined from the vicinty of the outer circumference position in the radial direction of the wane wheel 3A to the outward in the radial direction of the wane wheel 3A, so as to spread out against the upper wall 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sirocco fan used for a blower or the like of a vehicle air conditioner, and more particularly to a structure of a sirocco fan that can reduce blower noise and improve efficiency.

[0002]

2. Description of the Related Art A sirocco fan (a multi-blade fan) is an impeller having a large number of forward blades attached thereto, which rotates in a casing to blow air, and has the advantage of being small and inexpensive. Therefore, it is widely used for blowers of air conditioners for automobiles, and for supplying and exhausting ships and buildings.

A single intake type sirocco fan generally used as a blower for an automobile air conditioner will be described with reference to FIGS. In FIGS. 12 and 13, 1 is a casing, 2 is a bell mouth (a trumpet-shaped upper opening) formed on the upper surface of the casing 1, 3 is an impeller housed in the casing 1, and 4 is an impeller 3. It is a drive motor for rotationally driving. The impeller 3 includes a large number of blades 5 having a long blade width H in the rotation axis direction and a small blade chord length W in the radial direction.
Forward in the direction of rotation (the tip of the outer periphery of the impeller is inclined in the direction of rotation)
And arranged in a cylindrical shape, and its end is fixed to a ring-shaped frame 6 as shown in FIG. 14, for example.

Further, a conical boss portion 3a protruding upward is formed in the central portion of the impeller 3, and the boss portion 3 is formed.
The drive motor 4 is housed and arranged in a, and the impeller 3 is directly attached to the rotary shaft (not shown) of the drive motor 4. The impeller 3 is housed in the casing 1 while forming a flow passage 1a on the outer circumference in the radial direction, and the impeller 3 has a diameter substantially the same as that of the impeller 3 on the upper surface of the casing 1 facing the upper surface of the impeller 3. Bell mouth 2 is formed.

With the above structure, the drive motor 4 rotationally drives the impeller 3 in the casing 1 so that the arrow 7
The inflow air indicated by (4) is sucked from the bell mouth 2 and passes between the many blades 5 forming the impeller 3, and is blown in the direction of the white arrow 8 (outside the casing 1) through the flow path 1a on the outer periphery of the impeller 3. Then, the temperature is adjusted through an evaporator or a heater core (not shown), and then the air is blown into the vehicle compartment from an air outlet provided on a dashboard or the like.

[0006]

By the way, in recent automobiles, it is required to reduce various running noises such as engine noise and to provide a quiet and comfortable vehicle interior environment. In such a situation, it is naturally necessary to reduce the noise generated from the air conditioner. In the case of an air conditioning system for automobiles, a blower (that is, a sirocco fan) is a main noise source, and therefore it is expected that the noise reduction of the blower greatly contributes to the reduction of operating noise of the entire air conditioning system. Also, for sirocco fans used for other purposes, it is very preferable to reduce the operating noise.

Inflow air sucked from the bell mouth 2 into the casing 1 is separated near the end of the impeller 3 on the bell mouth 2 side as shown by an arrow 7a (see FIGS. 13 and 14).
As shown in FIG. 15, a large vortex generated in the upper part of the casing 1 is an important factor that causes noise.
Further, as shown in FIG. 15, the large vortex generated in the upper part of the casing 1 also causes a decrease in the operating efficiency of the sirocco fan.

The present invention was devised in view of the above problems. By reducing the vortex generated in the casing, noise can be reduced and loss can be reduced to improve operating efficiency. The purpose is to provide the sirocco fan who did.

[0009]

Therefore, the sirocco fan of the present invention has an impeller in which a large number of blades are arranged in a cylindrical shape with the forward direction in the rotational direction, and a flow passage is formed on the outer circumference in the radial direction of the impeller. A casing for accommodating the impeller is also formed, and an opening having a diameter substantially the same as the diameter of the impeller is formed on one surface of the casing facing one end surface of the impeller, and the impeller is defined as follows. The other surface of the casing facing the other end surface of the impeller, in which the inflow air sucked from the opening is blown to the outside of the casing through the flow passage by rotating in the casing. Is formed so as to extend from the vicinity of the outer peripheral position of the impeller in the radial direction toward the outer side in the radial direction of the impeller and to be expanded from one surface of the casing.

Further, at the end of the impeller on the side of the opening,
A shielding plate may be provided to shield the range corresponding to the length of 10 to 25% of the blade width from the end portion over the entire circumference. Furthermore, the inclination angles of the one surface and the other surface of the casing may be set to an angle that maximizes the effect on efficiency and noise.

[0011]

In the above-described sirocco fan of the present invention, the other surface of the casing having the opening portion, which faces one surface of the casing, extends from the vicinity of the radially outer peripheral position of the impeller to the outer side of the impeller in the radial direction of the impeller. It is formed to be inclined so as to spread from one surface. As a result, the flow of gas blown from the impeller to the flow passage radially outward of the impeller smoothly expands, the upper vortex can be suppressed, and the lower pressure in the casing (pressure on the other surface of the casing) is recovered. be able to. Especially, based on the results of the parameter study, the inclination angle of the one surface and the other surface of the casing is set to the angle that maximizes the effect on efficiency and noise, thereby effectively suppressing the upper vortex and recovering the lower pressure. It turns out that

Further, the blade width is 10 to 10 from the end of the impeller on the opening side.
In the range of 25%, the flow of the fluid is blocked by the shielding plate provided over the entire circumference. This makes it possible to remove the conventional frame that was the source of noise due to a large flow of obstacles, while gas cannot pass through the area that was the cause of many noises due to separation from the blade surface, The separation of the blade as a whole is reduced. Further, since the function of the blade has not been effectively exhibited in the region where the shield plate is provided, the efficiency is not lowered.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sirocco fan as an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view thereof, FIG. 2 is a perspective view showing its impeller, and FIG. 3 is a lower wall angle. Fig. 4 is an isoefficiency diagram for the upper wall angle, Fig. 4 is a contour noise diagram for the lower wall angle and the upper wall angle, and Fig. 5 is a schematic sectional view for explaining the lower wall angle and the upper wall angle in the casing. 6 is a graph showing the relationship between the flow rate coefficient and specific noise in the present embodiment in comparison with the conventional example, and FIG. 7 is a graph showing the relationship between the flow rate coefficient in this example and the efficiency in comparison with the conventional example. FIG. 8 is a graph showing the relationship between the frequency and the noise level in this embodiment in comparison with the conventional example, FIG. 9 is a diagram showing the flow of inflow air and vortex inside the casing in this embodiment, and FIG. Top shielding ratio, efficiency and specific noise in Examples Graph showing the relationship, FIG. 11 is a schematic cross-sectional view of the impeller for illustrating the upper end shield ratio in this embodiment. The same parts as those of the conventional example are designated by the same reference numerals as those described above, and detailed description thereof will be omitted.

As shown in FIG. 1, a casing 1A of the present embodiment accommodates an impeller 3A as shown in FIG. 2 while forming a flow passage 1a in its radial direction. On the upper wall 11 of the casing 1A facing the end face, the impeller 3
An opening 12 having a diameter substantially the same as the diameter A is formed. Also,
As shown in FIG. 2, the impeller 3A in this embodiment is provided with a ring-shaped shield plate 9 made of a thin plate over the entire circumference.

The shielding plate 9 is provided in the range of the length L in the span direction with respect to the blade 5 having the span H, and the ratio of the length L to the span H is appropriately in the range of 10 to 25%. It may be set (especially about 16% is the optimum value). The shield plate 9 is fixed to a cut surface formed by cutting out the upper end portion of each blade 5 on the upper wall 11 side, and the cutout shape of the upper end portion of each blade 5 is defined by the impeller 3
A substantially arc-shaped curve is formed so as to project downward from the inner upper end portion of A toward the outer side, and the maximum outer cut length is L. This curve is preferably set so as to be substantially parallel to the flow of the inflow air from the opening 12.

Further, the shielding ratio w / W of the upper end of each wing 5
Is 1.0 as a result of the parameter study shown in FIG. That is, the shield plate 9 is provided over the entire chord length of each wing 5.
To provide. Here, as shown in FIG. 11, the shielding ratio of the upper end of each blade 5 is the ratio of the width w of the impeller 3A in the radial direction of the shielding plate 9 to the chord length W of each blade 5, and this ratio w / When W is 1.0, as shown in FIG. 10, the effect on efficiency and noise is large.

On the other hand, the opening edge 1 of the casing 1A
As shown in FIG. 1, b is formed in a substantially parallel shape which is close to the shield plate 9 attached to the impeller 3A from above. Further, the lower wall (the lower surface of the casing 1A facing the lower end surface of the impeller 5) 10 of the casing 1A of the present embodiment is directed from the vicinity of the radially outer peripheral position of the impeller 5 to the outer side of the impeller 5 in the radial direction. , Is formed so as to be inclined from the upper wall 11 of the casing 1A.

In particular, as shown in FIG. 5, the casing 1A
The angle of the lower wall 10 with respect to the horizontal plane is the lower wall angle θ.₁(Under the direction
Is positive), the corner of the upper wall 11 of the casing 1A with respect to the horizontal plane
Degree is the upper wall angle θ₂(Downward is positive)
Lower wall angle θ obtained as a result of₁, Upper wall angle θ₂To
Fig. 3 and Fig. 4 show the iso-efficiency diagram and the iso-noise diagram, respectively.
Shown in. From these figures 3 and 4, the effect on efficiency and noise
Is the largest lower wall angle θ₁And upper wall angle θ₂Want
In the present embodiment, these lower wall angles θ ₁and
Upper wall angle θ₂The lower wall 10 and the upper wall 1 of the casing 1A
A tilt angle of 1 is set.

Next, the operation of the sirocco fan of the present embodiment constructed as described above will be explained. For example, in an automobile air conditioner, a drive motor (reference numeral 4 in FIG.
When the impeller 3A is rotated by the operation of (1), the outside air or the inside air is sucked according to the opening / closing of the inside / outside air switching damper (not shown), passes between the respective blades 5 of the impeller 3A through the opening 12, and the inside of the casing 1A The air is blown to the outside of the casing 1A through the channel 1a. Such a basic operation is exactly the same as the conventional one. The gas sent to the outside of the casing 1A is guided by a duct or the like, sent to an evaporator or a heater core (not shown) to adjust the temperature, and then blown out into the vehicle interior.

By the way, the inflow wind sucked from the opening 12 and passing through the impeller 3A changes its direction from the vertical direction (direction of the rotation axis of the impeller 3A) to the horizontal direction (radial direction of the impeller 3A). Flow along the plane of 5. Then, in the vicinity of the upper end portion of the blade 5 on the opening 12 side, peeling from the blade surface is likely to occur due to a demand for rapid direction change with small R, and thus in the present embodiment, as described above, A shielding plate 9 is provided in this area to limit the flow of inflow air.

As a result, as shown in FIG. 9, the ratio of the inflow air flowing along the blade surface at the central portion of the blade 5 becomes large, and it becomes possible to change the direction with a relatively large R as a whole. Therefore, the separation of the inflow air is reduced for the blade 5 as a whole,
Noise caused by this peeling is reduced. Further, by providing the shielding plate 9 and removing the conventional frame (see reference numeral 6 in FIG. 14) to reduce the separation of the blade 5 as a whole, the flow of the inflowing air becomes smooth and the efficiency of the sirocco fan is improved. It works effectively. The shield plate 9 in the present invention
Can also have the function of a reinforcing material as in the case of the frame in the conventional structure.

Further, in the present embodiment, referring to FIG. 3 and FIG.
As described above, the lower wall 10 and the upper wall 11 of the casing 1A
About the effect on efficiency and noise by parameter study
The optimum shape with the largest fruit, that is, inside the casing 1A
Consider the optimum shape to suppress vortices, and as a result,
Optimal lower wall angle θ that can reduce the scale of₁And above
Wall angle θ₂Found. That is, the lower wall angle θ₁And upper wall angle θ
₂The optimum angle (for example, the broken line arrow in FIGS. 3 and 4).
Lower wall angle and upper wall angle θ corresponding to the position indicated by mark ₂)
As a result, the inclination of the lower wall 10 becomes
Functioning like a user and flowing outward from the impeller 3A in the radial direction.
Smoothly expands the flow of gas blown into the path 1a
The upper vortex can be suppressed and the lower part in the casing 1A
Recovers the partial pressure (pressure on the lower wall 10 side of the casing 1A)
be able to.

As described above, according to the apparatus of this embodiment, the end of the impeller 3A on the side of the opening 12 is shielded over the entire circumference in the range of 10 to 25% (the optimum value is about 16%). By optimizing the shapes of the lower wall 10 and the upper wall 11 of the casing 1A, it is possible to reduce the size of the vortex generated in the separation and the casing 1A, noise can be greatly reduced, and loss can be reduced to reduce the operating efficiency. Can also be significantly improved.

The concrete effects are shown in FIGS. As shown in FIG. 6, the noise level is about 3 dB (A).
It can be reduced and the efficiency is about 5% as shown in Fig. 7.
Will be improved. By improving the efficiency by about 5%, the rotation speed can be reduced and the noise level can be further reduced by 1 dB when the air volume is the same. Further, as shown in FIG. 8, the noise level is reduced in almost the entire band as compared with the conventional one.

In the above-described embodiments, the case where the sirocco fan of the present invention is applied to the air conditioner for automobiles is explained, but the present invention is not limited to this, and other things such as ships and buildings. It is used as various blowers for supplying / exhausting objects, and the same effects as those of the above-described embodiment can be obtained.

[0026]

As described in detail above, according to the sirocco fan of the present invention, the other surface of the casing opposite to the other end surface of the impeller is provided with a radius of the impeller from the vicinity of the radial outer peripheral position of the impeller. With a very simple structure that is formed so that it extends outward in the direction of the casing so that it spreads out from one surface of the casing, the flow of gas blown out from the impeller to the flow passage radially outward is smoothly expanded. However, there is an effect that the upper vortex can be suppressed, the pressure on the other surface of the casing can be recovered, and noise can be reduced and efficiency can be improved. Particularly effective when one surface of the casing is formed so as to be substantially orthogonal to the rotation axis direction of the impeller and the inclination angle of the other surface of the casing is set to an angle that maximizes the effect on efficiency and noise. The upper vortex is suppressed and the lower pressure is recovered, resulting in the optimum shape for noise reduction and efficiency improvement.

In addition, the blade width is 10 to 10
In the range of 25%, the flow of the fluid is blocked by the shielding plate provided over the entire circumference, so that separation of the blade as a whole is reduced, which contributes to noise reduction and efficiency improvement.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a sirocco fan as one embodiment of the present invention.

FIG. 2 is a perspective view showing the impeller of the present embodiment.

FIG. 3 is a contour map for a lower wall angle and an upper wall angle.

FIG. 4 is a contour noise diagram for a lower wall angle and an upper wall angle.

FIG. 5 is a schematic cross-sectional view for explaining a lower wall angle and an upper wall angle in the casing of this embodiment.

FIG. 6 is a graph showing the relationship between the flow coefficient and the specific noise in the present embodiment in comparison with the conventional example.

FIG. 7 is a graph showing the relationship between the flow rate coefficient and efficiency in this example in comparison with the conventional example.

FIG. 8 is a graph showing the relationship between the frequency and the noise level in the present embodiment in comparison with the conventional example.

FIG. 9 is a diagram showing a state of an inflow air flow and a vortex inside the casing in the present embodiment.

FIG. 10 is a graph showing the relationship between the upper end shielding ratio and the efficiency and specific noise in this example.

FIG. 11 is a schematic cross-sectional view of an impeller for explaining the upper end shielding ratio in this embodiment.

FIG. 12 is a perspective view showing a conventional sirocco fan.

FIG. 13 is a sectional view showing a conventional sirocco fan.

FIG. 14 is an enlarged sectional view showing a main part of a conventional sirocco fan.

FIG. 15 is a view showing a state of vortices inside a casing of a conventional sirocco fan.

[Explanation of symbols]

 1A Casing 1a Flow path 1b Opening edge 3A Impeller 3a Boss 5 Blade 9 Shielding plate 10 Lower wall 11 Upper wall 12 Opening

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunio Nakagawa 5-3-8, Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation (72) Inventor Hiroshi China, 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Automotive Industry Co., Ltd.

Claims (3)

[Claims] 1. An impeller having a large number of blades arranged in a cylindrical shape in a front direction of rotation, and a casing accommodating the impeller with a flow passage formed on an outer periphery of the impeller in a radial direction. An opening having a diameter substantially the same as the diameter of the impeller is formed on one surface of the casing facing one end surface of the impeller, and the impeller is rotated in the casing to be sucked from the opening. In a sirocco fan configured to blow inflow air to the outside of the casing through the flow path, the other surface of the casing facing the other end surface of the impeller,
A sirocco fan, characterized in that the sirocco fan is formed so as to extend radially outward of the impeller from a position near a radial outer periphery of the impeller and to be expanded from one surface of the casing. 2. A shield plate is provided at an end portion of the impeller on the side of the opening, which shields a range corresponding to a length of 10 to 25% of a blade width from the end portion over the entire circumference. And
The sirocco fan according to claim 1. 3. The sirocco fan according to claim 1, wherein the inclination angles of the one surface and the other surface of the casing are set to an angle that maximizes the effect on efficiency and noise.