JP2000179496A - Multiblade fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit a reduction of discharge efficiency of an air by an impeller and a deterioration of a blowing performance and to inhibit an increase of a noise by a difference of a flow speed of an inflow air flow flowing from an air inlet port into the impeller at a circumferential position. SOLUTION: A distance L from a rotation axis of an impeller to a tip end of a bell mouth of a casing is varied so as to be gradually shortened in a rotation direction of the impeller from a throat portion 24 side L1 to an air discharge port 25 side L2 and is varied so as to be gradually lengthened from the air discharge port 25 side L2 to the throat portion 24 side L1. Thereby, a flow speed of an inflow air flow is made uniform and a blowing performance is enhanced to reduce a blowing noise.

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.

Hereinafter, the above-mentioned conventional multi-blade blower will be described with reference to the drawings. 6 and 7 show the structure of a conventional multi-blade blower. In the drawing, reference numeral 1 denotes a multi-blade blower, which comprises a bell mouth portion 3 forming an air intake 2, a spiral portion 4 and a throat portion 5, and a casing 7 having an air discharge port 6, and a main plate 8 accommodated in the casing 7
, An impeller 11 integrally formed with an annular side plate 9 and a plurality of blades 10, and a drive shaft 12 connected to the impeller 11
It is composed of The tip of the bell mouth portion 3 forming the air inlet 2 is formed concentrically with the drive shaft 12 as an axis, and the radius of curvature of the bell mouth portion 3 is the same in each cross section.

[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 12 and the impeller 11 rotates, air is sucked into the impeller 11 from the air intake 2, the dynamic pressure component is increased by the plurality of blades 10, and the dynamic pressure is reduced within the casing 7 by static pressure. After that, the air is discharged from the air discharge port 6 to the outside of the multi-blade blower 1.

[0006]

However, in the above configuration, the distance between the impeller 11 and the spiral part 4 near the throat part 5 of the casing spiral part 4 is small and the resistance is large, so that the air intake 2 The flow velocity of the inflow airflow sucked into the impeller 11 becomes slower, and conversely, the flow velocity increases near the discharge port 6, causing a difference in the inflow airflow velocity depending on the circumferential position. Changes, which causes a decrease in air blowing performance.

For this reason, there is a problem that the blowing performance of the multi-blade blower 1 is deteriorated and noise is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-blade blower in which the flow velocity of the inflowing air flowing into the impeller from the air intake is made uniform in the circumferential direction, thereby improving the blowing performance and reducing the blowing noise.

[0009]

In order to solve this problem, a multi-blade blower according to the present invention is arranged such that a radius of curvature of a bell mouth forming an air intake is changed by rotating an impeller from a throat portion side to an air discharge port side. In the direction from the air discharge port side to the throat portion side.

Alternatively, the distance from the rotation shaft of the impeller to the tip of the bell mouth forming the air intake of the casing is changed from the throat portion side to the air discharge port side so as to gradually decrease in the rotation direction of the impeller. The configuration is such that the length from the air discharge port side to the throat portion side is gradually increased.

With this configuration, the flow velocity of the inflowing air flowing into the impeller from the air inlet is made uniform at each circumferential position, so that the impeller discharges air efficiently and suppresses deterioration of the air blowing performance.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION
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, and a drive shaft connected to the impeller. The radius of curvature of the bell mouth was gradually changed from the throat portion side to the air discharge port side in the rotation direction of the impeller, and was gradually changed from the air discharge port side to the throat portion side. It is a multi-blade blower, and the inflow of air flowing into the impeller from the air intake is easy to flow in the throat side due to the large radius of curvature of the bell mouth, so that the inflow airflow velocity is uniform at each circumferential position Has an action.

According to a second aspect of the present invention, there is provided 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, and the impeller. A driving shaft connected to the, the distance from the shaft to the tip of the bell mouth of the casing is changed from the throat portion side to the air discharge port side so as to gradually decrease in the rotation direction of the impeller, A multi-blade blower with a gradually increasing length from the air discharge port side to the throat section side.Since the air intake port is large at the throat section side, air easily flows in and the inflow air flow velocity is uniform at each circumferential position It has the effect of becoming

[0014]

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 to avoid duplication, and the description is omitted.

(Embodiment 1) FIGS. 1 to 3 show a multi-blade blower according to Embodiment 1 of the present invention.

1 to 3, reference numeral 13 denotes a multi-blade blower, which comprises a bell mouth portion 15, a spiral portion 16, and a throat portion 17 forming an air intake port 14, and an air discharge port 18;
, A driving shaft 12 connected to the impeller 11, and a bell mouth 1 of the casing 19.
The radius of curvature R of 5 is such that the radius of curvature R1 is increased on the side of the throat portion 17 and the radius of curvature R2 is decreased on the side of the air discharge port 18, and the radius of curvature R of the bell mouth 15 is gradually reduced in the rotation direction of the impeller 11. The structure is changed so as to gradually increase from the air discharge port 18 side R2 to the throat 17 side R1.

With this configuration, when a driving force is applied to the drive shaft 12 and the impeller 11 rotates, air is sucked into the impeller 11 from the air intake 18, the dynamic pressure component is increased by the plurality of blades 10, and the inside of the casing 19 is increased. After the dynamic pressure is recovered to a static pressure by the above, it is discharged outside the multi-blade blower 13.

At this time, the impeller 11 is
Since the radius of curvature of the bell mouth 15 is large at the throat portion 17 side, the inflow air flowing into the air outlet becomes easy to flow in, and since the radius of curvature of the bell mouth 15 is small at the air discharge port 18 side, the inflow air flow can be suppressed. Further, the change in the radius of curvature of the bell mouth 15 is gradually reduced from the throat portion 17 side to the air discharge port 18 side in the rotation direction of the impeller 11, and is gradually reduced from the air discharge port 18 side to the throat portion 17 side. Thereby, the shape of the air intake 14 becomes smooth.

Therefore, the inflow airflow velocity is equalized at each circumferential position, and the impeller 11 efficiently evacuates air to the casing 19.
It discharges outside to improve the blowing performance and reduce the blowing noise.

(Embodiment 2) FIGS. 4 and 5 show a multi-blade blower according to Embodiment 2 of the present invention.

4 and 5, reference numeral 20 denotes a multi-blade blower, which includes a bell mouth portion 22 forming an air intake 21, a spiral portion 23, and a throat portion 24, and a casing 26 having an air discharge port 25. The throat portion is formed by an impeller 11 housed in a casing 26 and a drive shaft 12 connected to the impeller 11. The distance L from the rotation axis of the impeller 11 to the tip of the bell mouth 22 of the casing 26 is determined by a throat portion. The impeller 11 extends from the L1 side 24 to the air discharge port 25 side L2.
Is gradually changed in the rotation direction of the air outlet port 25, and the length from the air discharge port 25 side L2 to the throat portion 24 side L1 is gradually increased.

With this configuration, the air is easily introduced due to the large air inlet 21 on the throat portion 24 side, and the air is suppressed due to the small air inlet 21 on the air discharge port 25 side. Further, by gradually changing the flow rate, it is possible to make the inflow air flow velocity uniform at each circumferential position, and the impeller 11 efficiently discharges air to the outside of the casing 26 at each circumferential position, thereby improving the blowing performance and improving the blowing performance. Noise can be reduced.

[0024]

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. A driving shaft connected to the impeller, wherein the radius of curvature of the bell mouth is changed from the throat portion side to the air discharge port side so as to gradually decrease in the rotation direction of the impeller, and the air discharge port From the side to the throat part side, by gradually changing it, the inflow air flowing into the impeller from the air intake has a large radius of curvature on the throat part side, so that air flows in more easily than in the past. The inflow airflow velocity is made uniform at each circumferential position, so that the impeller can efficiently discharge air, improve the blowing performance, and reduce the blowing noise.

The distance from the shaft to the tip of the bell mouth of the casing is gradually changed from the throat portion side to the air discharge port side in the rotating direction of the impeller, and the distance from the air discharge port side to the throat portion side is changed. By gradually changing the length, the air intake is large at the throat part side, so that air easily flows in, the inflow air flow velocity is made uniform at each circumferential position, and the impeller efficiently discharges air out of the casing, The effect of improving the blowing performance and reducing the blowing noise can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a characteristic diagram showing a change in a radius of curvature R of FIG. 2;

FIG. 4 is a side view of a multi-blade blower according to Embodiment 2 of the present invention.

FIG. 5 is a sectional view of a main part of the multi-blade blower.

FIG. 6 is a cross-sectional view of a conventional multi-blade blower.

FIG. 7 is a sectional view of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Impeller 12 Drive shaft 13,20 Multi-blade blower 14,21 Air intake 15,22 Bell mouth part 16,23 Swirl part 17,24 Throat part 18,25 Air discharge port 19,26 Casing

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takumi Kida 4-5-2-5 Takaida Hondori, Higashiosaka-shi, Osaka Matsushita Refrigerator Co., Ltd. F-term (reference) 3H022 AA02 BA01 DA11 DA15 3H034 AA02 BB02 BB06 CC03 DD02 EE06 EE18 3H035 DD01 DD05

Claims (2)

[Claims] 1. 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, and a drive connected to the impeller. And the radius of curvature of the bell mouth is gradually changed from the throat part side to the air discharge port side in the rotation direction of the impeller, and gradually increased from the air discharge port side to the throat part side. Multi-blade blower changed to become. 2. 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, and a driving device connected to the impeller. The distance from the rotation axis of the impeller to the tip of the bell mouth of the casing is changed from the throat portion side to the air discharge port side so as to gradually decrease in the rotation direction of the impeller. A multi-blade blower whose length is gradually increased from the outlet to the throat.