JP2001349299A - Axial blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial blower that can improve characteristics of both large air quantity and high air pressure that a single conventional bell mouth alone can hardly achieve and that can reduce noise. SOLUTION: The axial blower is so constructed that a suction opening part is formed by a face member 2a with a suction opening, a wall surface 2b raised to an air delivery side over the overall circumference of the suction opening of the face member, and a connecting surface 2c for connecting the wall surface and the face member, and that the connecting surface is nonuniform in section along the radius of the opening part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial blower used for an indoor unit of an air conditioner, office equipment, or an industrial equipment such as a cooling / heating equipment using oil or gas, a boiler, and the like. In particular, by devising the shape of the suction opening of the axial blower (the so-called bell mouth shape), it is possible to improve both high air volume and high wind pressure characteristics that were difficult to achieve with a conventional bell mouth using a single bell mouth. The present invention relates to an axial blower capable of reducing noise.

[0002]

2. Description of the Related Art The structure of a conventional axial blower will be described with reference to the drawings. FIG. 9 is a sectional view of a conventional axial blower. As shown in the figure, in the axial blower, a propeller fan 12 is arranged in a suction opening (bell mouth) 11,
As the propeller fan 12 rotates, the arrow W
Wind is flowing in the direction. The suction opening 11 is provided with a face material 11 having a suction opening as shown in FIG.
a, a wall surface 11b erected on the wind discharge side over the entire circumference of the suction opening of the surface material 11a, and a connection surface 11c connecting the surface material 11a to the wall surface 11b, This connection surface 11c is usually formed from a curved surface having a constant radius R as shown in the figure. In the figure, 1
Reference numeral 3 denotes a mounting side member of the axial blower.

Since the blower is used for various purposes, it is preferable that the noise is as low as possible in consideration of the surrounding environment and the like. Recently, various studies have been made on the noise reduction of such a blower. For example, there is a type in which a groove 13 is formed in the suction opening of the blower over the entire circumference as shown in FIG. 10, and the action of the groove 13 changes the flow of air in the suction opening to reduce sound.

[0004]

However, the conventional suction opening having a devised shape has the same (uniform) radial cross-section over the entire circumference of the opening. Noise control has also reached its limits. further,
In the conventional axial flow blower, since the radial cross section of the bell mouth is constant, at the time of design, the wind pressure, without considering the shape of the bell mouth in consideration of the air volume, in the axial flow blower, depending on the usage mode, There were also problems such as insufficient wind pressure and air volume in the wind blowing range. In particular, in the conventional axial blower, increasing the air pressure characteristic while increasing the air volume characteristic is a contradictory request, and in order to satisfy such a request, change the shape of the fan while sacrificing one characteristic to some extent, The only way to change the diameter of the fan or increase the number of revolutions was forced to design in an unsatisfactory situation. Therefore, the present inventors have studied the shape of the suction opening from a completely new viewpoint, and found that the conventional fan does not change the rotation speed of the fan, that is, has a higher rotation speed than the conventional fan at the same rotation speed. We succeeded in developing a blower that satisfies both the characteristics of air volume and high wind pressure and that can significantly reduce the noise generated near the suction opening.
In this blower, by weaving both the high air volume shape and the high air pressure shape on the connection surface of the suction opening, in other words, by preventing the radial cross sections of the openings from being the same,
The noise can be reduced while satisfying both the pressure characteristic and the air volume characteristic by one bell mouth. Also, regarding the noise, the frequency of the sound generated around the suction opening is made different by preventing the radial cross section of the opening from being the same, and the noise is reduced by interference of the generated frequency.

[0005]

For this reason, the technical solution adopted by the present invention is as follows. In the suction opening of the axial blower, the suction opening has a surface material provided with a suction opening, and a suction material for the surface material. It is formed from a wall surface erected on the wind discharge side over the entire circumference of the opening, and a connection surface connecting the wall surface and the surface material, wherein the connection surface has a non-identical radial cross section at the opening. Which is a means for solving the problem.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of an axial blower according to a first embodiment of the present invention as viewed from a suction opening, FIG. 2 is a cross-sectional view taken along line AA of a bell mouth portion in FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along line CC of FIG.

In FIG. 1, reference numeral 1 denotes a propeller fan,
A suction opening member (bell mouth) 2 is arranged around the propeller fan 1. The suction opening member 2 includes a face member 2a having a suction opening as in the related art, a wall surface 2b erected on the wind discharge side over the entire circumference of the suction opening, and
It is formed of a connecting surface 2c for connecting the face material 2a and the wall surface 2b, and the connecting surface 2c is configured such that the radial cross sections in the openings are not the same.

More specifically, in the AA cross section shown in FIG.
The connection cross section 2c has a perfect circle R shape, the connection cross section 2c has an elliptical shape in the BB cross section shown in FIG. 3, and further has the connection cross section 2c in the CC cross section shown in FIG. Is an n-order curve, and the cross sections are connected by a smooth curve.

It should be noted that the shape of the connection section 2c is not limited to the above-mentioned one, and it is natural that other shapes can be used. The cross section of a certain part of the entire circumference of the part is different from the cross section of the remaining part, the whole circumference of the opening is divided into a plurality of parts, and the cross section of each part is different, and the cross-sectional shape Is a curved surface such as a convex shape (a perfect circle or an ellipse) on the fan side, and further includes a concave shape (n-th order shape) on the fan side. In other expressions, The term includes “not uniform”, “not uniform”, and the like. Also, it is natural that the cross-sectional shape can be freely modified and designed depending on the size of the propeller fan, the installation location of the propeller fan, and the like.

In the axial blower, when the motor rotates, the propeller fan 1 rotates, whereby air is sucked from the suction opening, and the wind flows in the direction of arrow W in the drawing. At this time, since the connection cross section 2c of the suction opening is not the same over the entire circumference, the frequency of the sound generated by the propeller fan is different at each part around the opening, and as a result, the mutual frequency Communicates with each other and the sound is reduced. Further, by devising the shape of the connection surface of the suction opening of the bell mouth, high wind pressure characteristics,
An axial blower that can satisfy both high air volume characteristics can be easily designed.

Next, a second embodiment of the present invention will be described. FIG. 5 is a front view of the axial blower according to the second embodiment viewed from the suction opening, and FIG. 6 is a DD of the bell mouth part in FIG.
It is sectional drawing. In this embodiment, the connection section in the left-right direction in FIG. 5 has a predetermined R shape as shown in FIG. 6, and the connection section in the up-down direction is linear, and a smooth curve is provided between the respective sections. It has a connected shape. Thus, also in this embodiment, the connection cross section is configured such that the radial cross section at the opening is not the same.

FIG. 7 is a graph showing a state in which noise is reduced. In the graph, (A) shows a case where the radial cross section of the suction opening is uniform, and (A) shows a case where the radial cross section of the suction opening is not the same (irregular shape). From this graph, it is clear that the one having a different connection section 2c has significantly reduced noise at the same air volume, and the one having a different connection shape has a larger air volume at the same noise level.

FIG. 8 is a comparison diagram of the static pressure-air flow characteristics when the curvature of the bell mouth connection cross section in the diagonal direction is increased and the curvature of the bell mouth connection cross section in the substantially perpendicular direction is reduced. In the graph, it can be seen that the fan having the diagonal bell mouth connection cross-sectional shape changed has a larger bell mouth connection cross-sectional shape over substantially the entire range for the fan having the same bell mouth connection cross-sectional shape.

As described above, in the suction opening, the connecting surface for connecting the face material provided with the suction opening and the wall surface erected on the wind discharge side over the entire circumference of the suction opening is formed by the opening. By ensuring that the radial cross-sections of the parts are not identical,
Compared with a conventional circular suction opening having the same cross section, noise can be significantly reduced, and the wind pressure or air volume can be adjusted. Depending on the shape of the bell mouth, the generated wind pressure and air volume may be lower than those of the conventional bell mouth, but when viewed with one bell mouth, the wind pressure is high by changing the shape of the connection cross section. The portion and the portion having a large air volume can be divided around the opening of the bell mouth, thereby satisfying both the characteristics of a large air volume and a high wind pressure as compared with the conventional bell mouth.

Although the embodiments have been described above, the present invention can be embodied in various other forms without departing from the spirit and main features thereof. Therefore, the above-described embodiment is merely an example and should not be construed as limiting. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

[0016]

As described in detail above, the axial blower according to the present invention is configured such that the radial cross section of the opening of the suction opening member disposed around the fan is not the same. The noise in a conventional axial blower can be greatly reduced, and the air volume can be greatly increased with the same noise value. In particular, the connection surface of the suction opening of the bell mouth is formed in a radial cross section of the opening. By not devising so that they are the same, a single bell mouth can satisfy both high wind pressure characteristics and high air volume characteristics, and can be used in a wide range of applications. it can.

[Brief description of the drawings]

FIG. 1 is a front view of an axial blower according to a first embodiment of the present invention as viewed from a suction opening.

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

FIG. 3 is a sectional view taken along line BB in FIG.

FIG. 4 is a sectional view taken along line CC in FIG.

FIG. 5 is a front view of an axial blower according to a second embodiment of the present invention, as viewed from a suction opening.

FIG. 6 is a sectional view taken along line DD in FIG. 5;

FIG. 7 shows the flow rate of an airflow blower using a 110φ propeller fan with a constant cross section in the radial direction of the suction opening (conventional type) and an airflow shape of an irregular shape (the present invention).
It is the figure which compared the characteristic of noise.

FIG. 8 is a comparison diagram of static pressure-air flow characteristics when the curvature of the bell mouth connection cross section in the diagonal direction is increased and the curvature of the bell mouth connection cross section in the substantially perpendicular direction is reduced.

FIG. 9 is a cross-sectional view of a conventional axial blower.

FIG. 10 is a cross-sectional view of another conventional fan.

[Explanation of symbols]

 Reference Signs List 1 propeller fan 2 suction opening member (bell mouth) 2a face material 2b wall face 2c connection face

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H032 BA03 CA02 CA04 3H034 AA02 AA18 BB02 BB08 CC03 DD02 EE06 EE08 3H035 DD04 DD06

Claims (2)

[Claims] 1. A suction opening of an axial blower, wherein the suction opening has a surface material provided with a suction opening, and a wall surface erected on the wind discharge side over the entire circumference of the suction opening of the surface material. An axial flow blower formed from a connecting surface that connects the wall surface and the face material, wherein the connecting surface has a non-identical radial cross section at an opening. 2. The axial blower according to claim 1, wherein the connection surface is formed as a curved surface.