JPH11343999A - Multiblade blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress counterflow of the discharged air flow from an impeller to a bell mouth part excessively inside a casing, suppress deterioration of the blowing performance, and suppress increase of a blowing noise. SOLUTION: A blower casing 14 has a convolution part 15 of such a structure that its radius r1 is greater on the main plate 6 side of impeller 9 and the radius r2 on the side with a side-plate 7 is made small, and the convolution part 15 is inclined from the main plate 6 side to the side-plate 7 side of the impeller 9. To the air stream willing to move toward a bell mouth 13, a force in the counter-bell mouth direction is applied from the wall surface of the casing 14 so as to suppress generation of a counterflow, and thereby the blowing performance is improved and an increase in the blowing noise is suppressed.

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 used for air conditioners and the like.

[0002]

2. Description of the Related Art Conventionally, a multi-blade blower of this type is often used because it is small in size and low in noise as compared with a turbo-type or a radial-type blower, but further reduction in noise has been demanded.

A conventional multi-blade blower is disclosed in
There is one disclosed in Japanese Patent No. 107000 gazette.

Hereinafter, the above-mentioned conventional multi-blade blower will be described with reference to the drawings. 4 and 5 show the structure of a conventional multi-blade blower. In the figure, reference numeral 1 denotes a multi-blade blower, a casing 5 comprising a bell mouth portion 3 forming an air inlet 2 and a spiral portion 4, and a casing 5
And an impeller 9 integrally formed with a main plate 6, an annular side plate 7 and a plurality of blades 8, and a drive shaft 10 connected to the impeller 9.

[0005] The operation of the multi-blade fan constructed as described above will be described below. First, when a driving force is applied to the shaft 10 and the impeller 9 rotates, air is sucked into the impeller 9 from the air intake 2, the dynamic pressure component is increased by the plurality of blades 8, and the dynamic pressure is reduced within the casing 5 by static pressure. After collecting
It is discharged out of the multi-blade blower 1.

[0006]

However, in the above configuration, the airflow discharged from the impeller 9 is almost a circumferential component, and the discharge airflow on the side plate 7 side of the impeller 9 is discharged into the casing 5. After that, a part F of the discharge airflow flows toward the bell mouth 3 while maintaining the circumferential direction component, and flows back into the side plate 7 of the impeller 9 from inside the bell mouth 3 as it is.

[0007] This backflow F not only leads to a loss of air flow itself, but also when the airflow flowing from the outside of the multi-blade blower 1 flows into the impeller 9, the flow collides and blocks the inflow passage. Further, the air volume is further reduced, and the flow of air flowing into the impeller 9 is disturbed, which causes turbulent noise.

Therefore, there is a problem that the aerodynamic performance of the multi-blade blower 1 is deteriorated and noise is increased. Therefore,
It is required that the discharge airflow flowing out of the impeller 9 be prevented from excessively flowing back into the bell mouth portion 3 inside the casing 5, to suppress the deterioration of the blowing performance, and to suppress the increase of the blowing noise.

SUMMARY OF THE INVENTION It is an object of the present invention to suppress a discharge airflow flowing out of an impeller in a multi-blade blower from excessively flowing back to a bell mouth portion inside a casing, to suppress a deterioration in ventilation performance, and to suppress an increase in ventilation noise. And

[0010]

In order to solve this problem, a multi-blade blower according to the present invention comprises a spiral casing having a bell mouth forming an air intake, a main plate accommodated in the casing and an annular main plate. A side plate and an impeller composed of a plurality of blades are provided.The spiral part of the casing has a larger spiral radius on the main plate side of the impeller and a smaller spiral radius on the side plate side, and the casing has an impeller from the main plate side of the impeller. Is provided on the side plate side.

According to this configuration, after the discharge airflow on the side plate side of the impeller is discharged into the casing, it also flows along the casing to the bell mouth side, but the casing is moved from the main plate side of the impeller to the side plate side of the impeller. As a result, a force acting on the anti-bellmouth side acts on the airflow moving toward the bellmouth side, thereby suppressing the flow. Therefore, it is possible to prevent the discharge airflow from the impeller from excessively flowing back into the bell mouth portion inside the casing, thereby suppressing deterioration of the air blowing performance.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION
A spiral casing having a bell mouth that forms an air intake, an impeller including a main plate, an annular side plate, and a plurality of blades housed in the casing, and a spiral portion of the casing is provided on a main plate side of the impeller. It is a multi-blade fan in which the spiral radius is increased and the spiral radius is reduced on the side plate side, and the casing is inclined from the main plate side of the impeller to the side plate side of the impeller, and part of the discharge airflow on the side plate side of the impeller is After being discharged into the casing, it flows to the bell mouth side along the casing, but since the casing is inclined from the main plate side of the impeller to the side plate side of the impeller, the airflow that tends to move to the bell mouth side is A force in the direction opposite to the bell mouth acts from the casing wall to suppress the flow. Therefore, it has an effect of suppressing the discharge airflow from the impeller from excessively flowing back into the bell mouth portion inside the casing.

According to a second aspect of the present invention, there is provided a spiral-shaped casing having a bell mouth forming an air intake, an impeller including a main plate, an annular side plate, and a plurality of blades housed in the casing. This is a multi-blade blower in which an inclined portion is provided at a corner portion between a flange portion and a spiral portion of a bell mouth, and a step or a protrusion along the spiral shape is further provided at the inclined portion, and an air flow moving toward the bell mouth side , A force in the direction opposite to the bell mouth acts from the casing wall surface to suppress the flow. Therefore, it has an effect of suppressing the discharge airflow from the impeller from excessively flowing back into the bell mouth portion inside the casing.

Further, since a step or a projection along the spiral shape is provided on the inclined portion, the backflow is effectively suppressed by the short inclined portion, and the backflow to the bell mouth portion is suppressed without increasing the outer diameter of the casing. Has an action.

According to a third aspect of the present invention, there is provided a spiral-shaped casing having a bell mouth forming an air intake, an impeller including a main plate, an annular side plate and a plurality of blades housed in the casing. It is a multi-blade blower provided with a ring-shaped projection having an inner diameter larger than the outer diameter of the impeller on the outer peripheral portion of the flange portion of the bell mouth, and a part of the discharge airflow on the side plate side of the impeller is discharged into the casing. After flowing along the casing to the bell mouth side, since the outer periphery of the flange portion of the bell mouth is provided with a ring-shaped projection having an inner diameter larger than the outer diameter of the impeller, it tries to move to the bell mouth side The generated airflow is blocked by the ring-shaped projections, and has the effect of preventing the discharge airflow from the impeller from excessively flowing back into the bell mouth portion inside the casing.

Further, a spiral chamber having a large circumferential component and a bellmouth chamber having a large radial component are separated by the ring-shaped projection, and the circumferential component of the airflow flowing backward to the bellmouth portion is reduced and flows into the blade. This also has the effect of reducing the collision loss of the airflow at the time.

[0017]

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

The same components as in the conventional example are denoted by the same reference numerals in order to avoid duplication, and description thereof will be omitted.

(Embodiment 1) FIG. 1 shows a multi-blade blower according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 11 denotes a multi-blade blower,
The casing 14 includes a casing 14 including a bell mouth portion 12 and a spiral portion 13 forming an air inlet 12, and an impeller 9 housed in the casing 14. The spiral portion 15 of the casing 14 is located on the main plate 6 side of the impeller 9. The spiral radius r1 is increased, and the spiral radius r2 is reduced on the side plate 7 side.
Of the impeller 9 is inclined from the main plate 6 side of the impeller 9 to the side plate 7 side.

With this configuration, when a driving force is applied to the shaft 10 and the impeller 9 rotates, air is sucked into the impeller 9 from the air intake 12, the dynamic pressure component is increased by the plurality of blades 8, and After collecting the dynamic pressure to static pressure,
It is discharged outside the multi-blade blower 11.

At this time, a part of the discharge airflow on the side plate 7 side of the impeller 9 is discharged into the casing, and
Of the impeller 9 from the main plate 6 side to the side plate 7 side, so that the air current moving to the bell mouth 13 side , A force in the direction opposite to the bell mouth acts from the wall surface of the casing 14 to suppress the flow.

Accordingly, it is possible to prevent the discharge airflow from the impeller 9 from excessively flowing back into the bell mouth 13 inside the casing 14 to improve the air blowing performance and to improve the air blowing performance.
When the airflow flowing from outside 1 flows into the impeller 9, the flow can be prevented from colliding with the backflow, and an increase in turbulence noise due to the turbulence of the inflow airflow can be suppressed.

(Embodiment 2) FIG. 2 shows a multi-blade blower according to Embodiment 2 of the present invention.

In FIG. 2, reference numeral 16 denotes a casing comprising a bell mouth portion 18 forming an air inlet 17 and a spiral portion 19, and reference numeral 20 denotes a flange portion 18a of the bell mouth 18.
And a spiral portion provided at the corner of the spiral portion 19,
A plurality of steps 2 along the spiral shape are provided on the inner surface of the inclined portion 20.
1 is provided. The step 21 is a plane 2 parallel to the spiral part 19.
1a and a surface 21b substantially parallel to the flange portion 18a.

According to this configuration, a part of the discharge airflow on the side plate 7 side of the impeller 9 tends to flow toward the bell mouth 18 along the spiral part 19 of the casing after being discharged into the casing 16. The flow is suppressed because strong resistance is received from the inclined part 20 provided on the inner surface of the inclined part 20 and the step 21 provided on the inner surface of the inclined part 20.

Accordingly, it is possible to prevent the discharge airflow from the impeller 9 from excessively flowing back toward the bell mouth portion 18 inside the casing 16 to improve the air blowing performance, and to prevent the airflow flowing from outside the casing 16 from flowing into the impeller. When flowing into the interior 9, the flow can be prevented from colliding with the backflow, and an increase in turbulent noise due to turbulence in the inflow airflow can be suppressed.

Further, the inclined portion 2 having a step 21 on the inner surface.
Since 0 is provided at the corner of the casing 16, the backflow can be effectively suppressed in a small space, and the blowing performance can be improved and the turbulent noise can be reduced without increasing the outer diameter and outer dimensions of the casing 16.

In the present embodiment, the inclined portion 20 has a linear shape, but the same effect can be obtained by using a curved shape. Further, a plurality of steps 21 along the spiral shape are provided on the inner surface of the inclined portion 20, but the same effect can be obtained by providing a projection.

(Embodiment 3) FIG. 3 shows a multi-blade blower according to Embodiment 3 of the present invention.

In FIG. 3, reference numeral 22 denotes a casing formed of a bell mouth portion 24 and a spiral portion 25 forming an air inlet 23. The outer periphery of the bell mouth 24 has a ring shape whose inner diameter is larger than the outer diameter of the impeller 9. Are provided.

According to this configuration, a part of the discharge airflow on the side plate 7 side of the impeller 9 tends to flow toward the bell mouth 24 along the spiral part 25 of the casing after being discharged into the casing 22, but the ring is one end. The protrusion 26 is dammed. Therefore, the discharge airflow from the impeller 9 is
2 suppresses excessive backflow to the bell mouth portion 24 inside, improves the air blowing performance, and prevents the flow colliding with the backflow when the airflow flowing from the outside of the casing 22 flows into the impeller 9. Thus, the increase in turbulent noise due to the turbulence of the inflow airflow can be suppressed.

Moreover, the spiral chamber 27 having a large circumferential component and the bell mouth chamber 28 having a large radial component are separated by the ring-shaped projection 26, and the circumferential component of the airflow flowing back to the bell mouth portion 24 is reduced. It is possible to reduce the collision loss of the airflow when flowing into the blades 8, and further to improve the blowing performance and reduce the turbulent noise.

Although the above embodiment has been described with two air intakes having two air intakes, the same effect can be obtained with a single air intake having one air intake.

[0035]

As described above, according to the present invention, a spiral casing having a bell mouth forming an air intake, an impeller housed in the casing and comprising a main plate, an annular side plate, and a plurality of blades are provided. The spiral part of the casing has a larger spiral radius on the main plate side of the impeller and a smaller spiral radius on the side plate side, and the casing is inclined from the main plate side of the impeller to the side plate side of the impeller, whereby a bell is provided. A force acting on the anti-bellmouth side acts on the airflow that is going to move to the mouse side, preventing the discharge airflow from the impeller from excessively flowing back to the bellmouth part inside the casing, improving the blowing performance and Thus, an effect of preventing an increase in turbulent noise due to turbulence of the inflow airflow can be obtained.

Further, the bell mouth is provided with an inclined portion at the corner between the flange portion and the spiral portion, and further provided with a step or a projection along the spiral shape on the inclined portion, so that the bell mouth side is provided. A force in the direction opposite to the bell mouth acts on the airflow to be moved from the casing wall surface, and while suppressing the discharge airflow from the impeller from excessively flowing back to the bellmouth portion inside the casing, improving the blowing performance, The effect of preventing an increase in turbulent noise due to turbulence of the inflow airflow is obtained.

Further, since a step or a projection along the spiral shape is provided on the inclined portion, the backflow can be effectively suppressed by the short inclined portion, and the blowing performance can be improved without increasing the outer diameter of the casing. The effect is obtained.

Further, by providing a ring-shaped projection having an inner diameter larger than the outer diameter of the impeller on the outer peripheral portion of the flange portion of the bell mouth, the air current moving to the bell mouth side is formed in a ring shape. It prevents the airflow from the impeller from flowing back excessively to the bellmouth inside the casing, improves the air blowing performance, and prevents the increase in turbulence noise due to the turbulence of the inflow airflow. The effect is obtained.

Furthermore, the circumferential component of the airflow flowing backward to the bell mouth portion is reduced by the ring-shaped projections, so that the collision loss of the airflow when the backflow flows into the blade is reduced, and the effect of reducing turbulent noise is obtained. Can be

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a multi-blade blower according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view of a main part of a multi-blade blower according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a multi-blade blower according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a conventional multi-blade blower.

FIG. 5 is a sectional view of a main part of the conventional example.

FIG. 6 is a sectional view of the conventional example.

[Explanation of symbols]

 Reference Signs List 6 Main plate 7 Side plate 8 Blade 9 Impeller 11 Multi-blade blower 12 Air intake 13 Bell mouth 14 Casing 15, 20 Inclined portion 21 Step 26 Ring projection

Claims (3)

[Claims] 1. A spiral casing having a bell mouth forming an air intake, an impeller including a main plate, an annular side plate and a plurality of blades housed in the casing, wherein the spiral portion of the casing is A multi-blade fan in which the spiral radius is increased on the main plate side of the impeller and the spiral radius is reduced on the side plate side, and the casing is inclined from the main plate side of the impeller to the side plate side of the impeller. 2. A spiral-shaped casing having a bell mouth forming an air intake, an impeller including a main plate, an annular side plate, and a plurality of blades housed in the casing, wherein a flange portion of the bell mouth is provided. A multi-blade blower in which an inclined portion is provided at a corner portion with a spiral portion, and a step or a projection portion along the spiral shape is provided at the inclined portion. 3. A bell-shaped casing having a bell mouth forming an air intake, an impeller comprising a main plate, an annular side plate, and a plurality of blades housed in the casing, wherein a flange portion of the bell mouth is provided. A multi-blade blower provided with a ring-shaped projection having an inner diameter larger than an outer diameter of the impeller on an outer peripheral portion.