JPH05106592A - Axial flow fan for air-conditioner - Google Patents

Abstract

PURPOSE:To enhance the blowing performance and reduce noise by furnishing at least one cylinder at the periphery of a 1st impeller, which is mounted on a rotary shaft, in such a way as surrounding the impeller, and forming a 2nd impeller on the periphery of the cylinder or cylinders. CONSTITUTION:An axial flow farm 24 is composed of a 1st impeller 13 fitted with a fan boss 12 where a shaft fixing part 11 is formed, a ring 14 as a cylindrical body formed on the periphery of the impeller 13 in such a way as surrounding it, and a 2nd impeller 15 formed on the periphery of this ring 14. These impellers 13, 15 are each fitted with four blades 16, 17, but if necessary, the 1st impeller 13 will have more blades 16 than the 2nd impeller 15. The 2nd impeller mounting position is set off in the circumferential direction from the 1st impeller mounting position. Further, the ring 14 is, if necessary, formed tapered so that the dia. enlarges gradually from the suction side toward the blowout side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial flow fan used in an outdoor unit of an air conditioner.

[0002]

2. Description of the Related Art An air blower for an outdoor unit of an air conditioner generally uses an axial flow fan having a plurality of blades (blades) having a single curved surface attached to the outer periphery of a boss portion. However, such an axial fan has drawbacks that it is difficult to improve the blowing performance and it is difficult to mechanically control high frequency noise.

In order to eliminate such drawbacks, a blower as shown in FIG. 10, for example, has been proposed. This blower has a hub 2 having a truncated cone shape at one end of a biaxial motor 1.
The main impeller 4 provided with a plurality of blades 3 on the outer peripheral portion of
A follower impeller 5 is provided at the other end, and an air suction port 6 is provided at the end surface of the hub 2.
It has a structure with a hole.

[0004]

However, since the blower has a structure in which the mixed flow fan is attached to one end of the biaxial motor 1 and the axial flow fan is attached to the other end, the number of parts and the depth dimension are increased. There are drawbacks.

Therefore, an object of the present invention is to provide an axial-flow fan for an air conditioner, which can improve the blowing performance and reduce the noise, and which does not increase the number of parts and the depth dimension.

[0006]

In order to achieve the above object, the present invention is formed so as to surround a first impeller mounted on a rotary shaft and the outer periphery of the first impeller. It is characterized by including at least one cylindrical body and a second impeller formed on the outer circumference of the cylindrical body.

[0007]

According to the above construction, by appropriately selecting the positions and the number of blades of the first impeller and the second impeller arranged inside and outside the cylindrical body, it is easy to improve the blowing performance and reduce the noise. Can be achieved. Further, since the first impeller and the second impeller are concentrically formed via the cylindrical body, the number of parts and the depth dimension can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1 and 2 show a first embodiment of the present invention, in which an axial fan 24 has a shaft fixing portion 11 for mounting on a rotary shaft (not shown). First impeller 13 integrally having the fan boss 12
And a ring 14 that is a cylindrical body formed so as to surround the first impeller 13 and surrounds the first impeller 13, and a second impeller 15 that is formed on the outer periphery of the ring 14.

The first impeller 13 is formed by four blades 16 attached to the fan boss 12, and a ring 14 formed of a thin plate is concentrically fixed integrally with the outer peripheral end of the blade 16. ing. The second impeller 15 is also composed of four blades 17, and is concentrically and integrally fixed to the outer wall of the ring 14. These blades 16 and 17 are formed with optimum curved surface shapes and optimum mounting angles at their radial positions, in other words, optimum peripheral speeds.

Further, in this embodiment, the first impeller 13 and the second impeller 15 are formed so as to have different phases, and as shown in FIG. The trailing edge a of the blade 16 of 13 and the corresponding second impeller 1
The rear edge b of the blade 17 of FIG.

By virtue of such construction, the ring 1
The curved shapes of the blades 16 and 17, the mounting angle, the number of blades, etc. can be optimized between the inside and the outside of the blade 4, and the improvement of the blowing performance can be achieved without increasing the number of parts and the depth dimension. By offsetting the mounting positions of the blades 16 and 17 in the circumferential direction, a phase difference in pressure pulsation on the blow side and the suction side occurs, the pressure fluctuation near the ring 14 is canceled, and noise generation is suppressed. You can

FIG. 3 shows a specific example in which the axial fan of the first embodiment is applied to an outdoor unit of an air conditioner. The outdoor unit includes a heat exchanger 22 in a cabinet 21 and a heat exchanger 22. A compressor 23 for sending a refrigerant is provided and configured, and a base 26 is provided on the bottom plate 25 near the heat exchanger 22.
A motor 27 is installed via. Axial fan 24
Is provided with the fan boss 12 attached to the output shaft 28 of the motor 27.

The present inventors measured the noise in the outdoor unit having the structure shown in FIG. 3 in order to confirm the effect of the present invention. The measurement is to analyze the frequency of noise at a position 1 m from the suction side, the same conditions such as rotation speed (= 740 rpm) are used, and the conventional axial fan (having a blade with a single curved surface) Compared with an outdoor unit equipped with. The frequency analysis results are shown in FIG. 4 (present invention) and FIG. 5 (conventional). As shown in the figure, in the outdoor unit provided with the axial fan 24 of the present invention, it was particularly effective in reducing the components of the fourth order and above.

Next, referring to FIGS. 6 and 7, the second embodiment of the present invention will be described.
An example will be described.

In the second embodiment, as in the first embodiment, a first impeller 32 composed of four blades 31, a ring 33 formed on the outer circumference thereof, and a first impeller mounted on the outer circumference thereof are provided. And the second impeller 35 including the blades 34 having different phases. The diameter of the ring 33 is gradually increased from the suction side toward the blowout side. That is, the ring-side radius c of the ring 33 is formed to be larger than the suction-side radius d (c> d).

Due to such a structure, the ring 33
The flow in the vicinity is improved and the fluid performance can be improved. Other configurations and operational effects are similar to those of the first embodiment.

Next, referring to FIGS. 8 and 9, the third embodiment of the present invention will be described.
An example will be described.

In the third embodiment, a first impeller 41 having a fan boss 12 as a boss mounted on a rotary shaft (not shown) and an outer periphery of the first impeller 41 are surrounded. An inner ring 42 as a first cylindrical body formed as described above, a second impeller 43 formed on the outer periphery of the inner ring 42, and a second
The outer ring 44, which is a second cylindrical body, is formed on the outer circumference of the inner impeller 43 so as to surround it, and the second outer impeller 45 is formed on the outer circumference of the outer ring 44. .

The first impeller 41 has six blades 46.
The inner ring 42 is concentrically fixed to the outer peripheral end of the inner ring 42. The second inner impeller 43 is formed of five blades 47, and the outer wall of the inner ring 42 and the outer ring 4 are formed.
It is fixed to the inner wall of No. 4 so as to be hung on these. The second outer impeller 45 is formed by four blades 48, and the inner end is fixed to the outer wall of the outer ring 44.
That is, the blades 46, 4 of the impellers 41, 43, 45
The number of 7,48 is increased as it goes radially inward. Also, by changing the number of blades,
These phase differences naturally occur. Similar to the first and second embodiments, each of these blades 46, 47 and 48 is formed so as to have an optimum curved surface shape and mounting angle for its peripheral speed.

With this configuration, noise can be suppressed more than in the above embodiment. That is, the blade rotation sound frequency f is expressed by the following equation.

F = NZ / 60 Here, N is the fan rotation speed (rpm), and Z is the number of blades.

Therefore, the impeller 4 having the same rotation speed is integrally formed.
In Nos. 1, 43, and 45, the air blow work is increased by increasing the number of inner blades, and at the same time, the air volume is increased, and at the same time, the harmonic component can be reduced by decreasing the number of outer blades. It is a thing.

Other functions and effects are similar to those of the first and second embodiments.

In the above embodiment, the number of blades is 4-6.
However, the present invention is not limited to this, and may be increased or decreased as necessary.

[0026]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) By improving the position and number of blades of the first impeller and the second impeller arranged inside and outside the cylindrical body, it is possible to easily improve the blowing performance and reduce the noise.

(2) Since the first impeller and the second impeller are concentrically formed through the cylindrical body, the number of parts and the depth dimension can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of an axial-flow fan showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

3 is a cross-sectional plan view of an outdoor unit in which the axial fan of FIG. 1 is used.

FIG. 4 is a noise analysis diagram when the axial fan of the present invention is operated.

FIG. 5 is a noise analysis diagram when a conventional axial fan is operated.

FIG. 6 is a front view of an axial flow fan showing a second embodiment of the present invention.

7 is a sectional view taken along the line BB of FIG.

FIG. 8 is a front view of an axial flow fan showing a third embodiment of the present invention.

9 is a cross-sectional view taken along the line CC of FIG.

FIG. 10 is a cross-sectional view showing an example of a conventional axial fan.

[Explanation of symbols]

 13 First Impeller 14 Ring (Cylindrical Body) 15 Second Impeller

Claims (4)

[Claims] 1. A first impeller mounted on a rotating shaft, at least one cylindrical body formed so as to surround the first impeller on the outer circumference of the first impeller, and formed on the outer circumference of the cylindrical body. An axial fan for an air conditioner, comprising: 2. The axial fan for an air conditioner according to claim 1, wherein the mounting position of the second impeller is displaced from the mounting position of the first impeller in the circumferential direction. 3. The axial fan for an air conditioner according to claim 1, wherein the diameter of the cylindrical body is gradually increased from the suction side to the blowing side. 4. The axial fan for an air conditioner according to claim 1, wherein the first impeller has more blades than the second impeller.