JPH10299695A - Axial flow fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noises and generate a large amount of blowing and intensive static pressure evenly all over an inner peripheral part and an outer peripheral part by connecting a first fan in which blades are arranged on an outer peripheral part of a cylindrical outer boss, and a second fan arranged on an inner side of the outer boss, to a rotary shaft of the same motor. SOLUTION: An axial flow fan 6 is mainly composed of a first fan 17 in which a plurality of blades 16 are arranged on an outer periphery of a cylindrical outer boss 15 and a second fan 18 arranged on an inner side of the outer boss 15. Both fans 17, 18 are connected to a rotary shaft 19 of the same fan motor 9. Generation of a large blowing amount and intensive static pressure is enabled evenly all over an inner peripheral part and an outer peripheral part within a limited space, by enlarging areas of blades 16, 25. Rotational speed of the first fan 17 is decreased, while that of the second fan 18 is increased, through a deceleration mechanism 25 for unnecessitating excessive increase of the rotational speed of the first fan 17. Noises are thus reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Generally, an outdoor unit of an air conditioner is provided with an outdoor heat exchanger inside an outdoor unit main body, and an axial fan opposed to the heat exchanger to blow air from the outdoor to the heat exchanger. Thus, heat exchange is performed between the outside air and the refrigerant flowing in the heat exchanger, so that the refrigerant is condensed or evaporated.

[0003] As shown in FIG.
Is composed of a boss portion 52 and a plurality of blades 53 attached to the outer periphery of the boss portion 52. The boss portion 52 is connected to a rotating shaft of a fan motor (not shown) supported by a motor base (not shown). And blow the air by rotating the fan motor at a predetermined number of revolutions.

[0004]

Incidentally, in order to increase the efficiency of heat exchange, it is necessary to generate a large air volume and a large static pressure with an axial fan. However, when the axial fan is rotated at a certain number of revolutions, the energy generated in the axial fan increases in the outer periphery and decreases in the inner periphery, and the air volume and pressure in the inner periphery decrease. I was

[0005] The diameter and depth of the axial fan are as follows:
Due to the limitation, in order to generate a large air volume and a large static pressure in the entire heat exchanger, it was necessary to increase the rotational speed of the axial fan to increase the energy. However, there is a problem that the noise increases as the rotational speed of the axial fan increases.

Accordingly, an object of the present invention is to provide an axial fan capable of reducing noise and generating a large air volume and a large static pressure uniformly in the entire inner and outer peripheral portions.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a first fan having a blade mounted on the outer periphery of a cylindrical outer boss, and a second fan disposed inside the outer boss. A first fan and a second fan are connected to a rotation shaft of the same motor.

The inner boss portion of the second fan is connected to the rotating shaft of the motor, and the outer boss portion of the first fan is connected to the rotating shaft via a reduction mechanism comprising a torque converter. It is preferable that the rotation speed of the second fan be different from that of the second fan.

Further, it is preferable that the speed reduction mechanism has a reduction ratio set such that the second fan rotates at a speed of 1.5 times or more the rotation speed of the first fan.

[0010] The blades of the first fan and the second fan are mounted so that their mounting directions are reversed, and the speed reduction mechanism controls the rotation of the second fan in a direction opposite to the rotation direction of the first fan. It may be set to rotate in the direction.

According to the above configuration, the area of the blade portion is increased, and the rotational speed of the first fan on the outer peripheral side is reduced and the rotational speed of the second fan on the inner peripheral side is increased through the speed reduction mechanism. By doing so, a large air volume and a large static pressure can be uniformly generated over the entire inner peripheral portion and the outer peripheral portion. Also,
Since the rotational speed of the first fan on the outer peripheral side does not need to be increased more than necessary, noise can be minimized.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a front view and a sectional view showing an embodiment of an axial fan according to the present invention, FIG. 2 is an exploded perspective view of the axial fan according to the present invention, and FIG. It is sectional drawing which showed the outline of the air conditioner outdoor unit in which such an axial fan was installed.

First, the configuration of the axial fan according to the present invention will be described.

As shown in FIG. 3, the air conditioner outdoor unit 1 is provided with a heat exchanger 3 so as to cover the inside rear side of the main body casing 2, and a heat exchanger 3 is provided at a front portion thereof.
An axial fan 6 for sucking outside air from the air suction port 4 on the rear surface portion through the heat exchanger 3 and blowing it out from the air outlet 5 on the front surface portion is provided. A fan guard 7 is attached to the main body casing 2 so as to cover the front surface of the axial fan 6, and a bell mouth 8 is provided around the axial fan 6 so as to surround the fan guard 7. I have. Behind the axial fan 6, a fan motor 9 for rotating the fan is fixed to a motor base 10 erected substantially at the center of the bottom of the main body casing 2. In the drawings, reference numeral 11 denotes a compressor, 12 denotes an electric component storage unit, and 14 denotes a refrigerant pipe storage unit.

As shown in FIGS. 1 and 2, the axial fan 6
A plurality of blades 16 on the outer periphery of the cylindrical outer boss 15
The first fan 17 having the outer boss 15
The first fan 17 and the second fan 18 are connected to the rotation shaft 19 of the same fan motor 9. Things.

The rotation shaft 19 of the fan motor 9 has a reduction mechanism 21 composed of a torque converter near the front end thereof, and is divided into two parts. Here, the front rotation shaft 19 is referred to as a front rotation shaft 19a, and the rear rotation shaft 19 on the motor side is referred to as a rear rotation shaft 19b. The speed reduction mechanism 21 can adjust the number of rotations of the front rotation shaft 19a and the rear rotation shaft 19b, and can reverse the rotation direction.

Inside the outer boss 15 of the first fan 17, four spokes 2 for connecting to the front rotating shaft 19a are provided.
2 are formed radially. The spokes 22 extend from the inside of the front end of the outer boss 15 to the front rotation shaft 1 at the center thereof.
9a, and is connected to the front rotation shaft 19a.

The spokes 22 are connected to the first fan 1
7 for connecting and fixing to the rotating shaft 19,
The number is not limited to four, and the second fan 1
In order to increase the amount of air blow of No. 8, it is preferable to increase the opening area in front of the inside of the outer boss 15 by reducing the number or reducing the width.

The second fan 18 is mounted on the rear rotating shaft 19b through a mounting portion 23 provided so as to cover the vicinity of the front end thereof, and has a bottomed cylindrical shape connected to the mounting portion 23. It comprises a boss 24 and a plurality of blades 25 mounted on the outer periphery of the inner boss 24.

The inner boss portion 24 is disposed so that the opening side of the bottomed cylinder faces forward, and the bottom portion is fixedly attached to the attachment portion 23. The speed reduction mechanism 21 is configured to be housed inside the inner boss portion 24.

The blade 25 is formed in the same direction as the blade 16 of the first fan 17 and the second fan 18
Rotates in the same direction as the first fan 17. In this case, the speed reduction mechanism 21 determines that the rotation speed of the rotation shaft 19b after the second fan 18 is connected is at least 1.5 times the rotation speed of the front rotation shaft 19a to which the first fan 17 is connected (this embodiment). The speed reduction ratio is set to 1.5 times in the embodiment).

The second fan 18 housing the speed reduction mechanism 21 is housed behind the spoke 22 inside the outer boss 15.

The outer diameter D1 of the first fan 17 is substantially equal to the outer diameter of the conventional axial flow fan 51 (see FIG. 6), and the outer diameter D2 of the second fan 18 is Is formed so as to be approximately half of the outer diameter D1.

Next, the operation of the axial fan will be described.

When the fan motor 9 is driven, the rear rotation shaft 19b rotates and the front rotation shaft 19b also rotates at the reduced rotation speed. Here, the rotation speed of the rear rotation shaft 19b is set to 1.5 times the rotation speed of the front rotation shaft 19a by the reduction mechanism 21.
The second fan 1 on the inner peripheral side
8 rotates at a peripheral speed 1.5 times that of the outer peripheral first fan 17.

Here, a comparison between the axial fan according to the present invention and a conventional axial fan will be described with reference to a PQ diagram of FIG. In the figure, the airflow characteristic a of the conventional axial fan is indicated by a broken line, the airflow characteristic b of the first fan is indicated by a one-dot chain line, the airflow characteristic c of the second fan is indicated by a two-dot chain line, and the axial flow of the first and second fans The air volume characteristic d of the fan 6 is indicated by a solid line. At this time, the rotation speed of the axial fan is the same as the rotation speed N of the conventional axial fan, the rotation speed N1 of the first fan 17 is the same as this, and the rotation speed N2 of the second fan 18 is 1 of N1. .5 times. As shown, the airflow characteristic d of the axial fan 6 according to the configuration of the present invention is the sum of the airflow characteristic b of the first fan 17 having the outer diameter D1 and the airflow characteristic c of the second fan 18 having the outer diameter D2. As a result, the air flow characteristics a of the conventional axial flow fan are greatly improved, and a large air flow and a large static pressure can be efficiently generated in a limited space.

As a result, the heat exchange efficiency of the outdoor unit of the air conditioner can be improved, and the outdoor unit can be downsized.

The air volume characteristics can be changed by changing the outer diameter ratio or the rotation speed ratio between the first fan 17 and the second fan 18.

As described above, the second fan 18 is provided inside the outer boss portion 15 of the first fan 17 on the outer peripheral side, and the area of the blade portion is made larger than that of the conventional axial flow fan. When the first fan 17 is rotated at the rotation speed, a larger air volume and a larger static pressure can be generated as compared with the related art as described above.

Further, since the peripheral speed of the first fan 17 is made lower than the peripheral speed of the second fan 18, even if the rotational speed of the second fan 18 is increased, the rotational speed of the first fan 17 on the outer peripheral side is increased. There is no need to increase the number more than necessary, and noise can be minimized.

Next, another embodiment will be described.

In the above embodiment, the first fan 1
The blade 16 of the second fan 18 and the blade 25 of the second fan 18 are formed in the same direction. However, as shown in FIG. The second fan 18 is formed so that the direction of the first fan 17 is opposite to the direction of the blade 16 of the first fan 17, and the speed reduction mechanism 21
7 is set to rotate in a rotation direction opposite to the rotation direction. In addition, the same components as those of FIG. 1 in other configurations are denoted by the same reference numerals, and description thereof will be omitted.

According to the above configuration, in addition to the operation described in the above embodiment, the flow of the air blown from the axial fan 6 is controlled by the first fan 17 on the outer peripheral side and the second fan 18 on the inner peripheral side.
Therefore, the two blowing winds cancel each other out, and are blown straight out. Thus, noise due to the blowing wind can be reduced.

[0035]

In summary, according to the present invention, by increasing the area of the blade portion, a large air volume can be uniformly distributed over the entire inner and outer peripheral portions in a limited space.
An excellent effect that a large static pressure can be generated is exhibited.

Further, the rotational speed of the first fan on the outer peripheral side is made slower and the rotational speed of the second fan on the inner peripheral side is made faster through the speed reduction mechanism, whereby the rotational speed of the first fan on the outer peripheral side is increased. Since it is not necessary to raise the noise more than necessary, noise can be minimized.

[Brief description of the drawings]

FIG. 1A is a front view and FIG. 1B is a cross-sectional view showing an embodiment of an axial fan according to the present invention.

FIG. 2 is an exploded perspective view showing the axial fan of FIG. 1;

3A is a horizontal sectional view, FIG. 3B is a vertical sectional view, and FIG. 3C is a rear view schematically showing the outdoor unit of the air conditioner.

FIG. 4 is a graph showing air volume characteristics of an axial fan.

FIG. 5 is a front view showing an axial fan according to another embodiment.

FIG. 6 is a front view showing a conventional axial fan.

[Explanation of symbols]

 Reference Signs List 6 axial fan 9 fan motor (motor) 15 outer boss 16 blade 17 first fan 18 second fan 19 rotating shaft 21 reduction mechanism 24 inner boss 25 blade

Claims (5)

[Claims] 1. A first fan having a blade mounted on the outer periphery of a cylindrical outer boss, and a second fan disposed inside the outer boss, wherein the first fan and the second fan are provided. The axial fan is connected to a rotating shaft of the same motor. 2. An inner boss portion of the second fan is connected to a rotating shaft of a motor, and an outer boss portion of the first fan is connected to the rotating shaft via a speed reduction mechanism. 2. The axial flow fan according to claim 1, wherein the number of rotations of the fan is varied. 3. The axial fan according to claim 1, wherein the speed reduction mechanism comprises a torque converter. 4. The speed reduction mechanism according to claim 1, wherein the reduction ratio is set such that the second fan rotates at a speed of 1.5 times or more the rotation speed of the first fan. 3. The axial fan according to 1. 5. The blades of the first fan and the second fan are mounted so that their mounting directions are opposite to each other, and the speed reduction mechanism causes the second fan to rotate in a direction opposite to the rotation direction of the first fan. The axial fan according to any one of claims 1 to 4, wherein the axial flow fan is set to rotate in the rotation direction.