JPH03294699A - Impeller of blower - Google Patents

Abstract

PURPOSE:To reduce a pressure variation following an exfoliation of the airflow and to achieve a further lower noise by providing plural vanes around a hub, and arranging plural dimples of about a circular form on the lower pressure surface side of the vanes. CONSTITUTION:An impeller (a) has plural vanes (b) at the hub (f) of about a conical trapezoid form, and plural dimples (g) of about a circular form are provided on the lower pressure surface sides of the vanes (b). In this case, the typical size phi of the dimples (g) is made 1mm to 20mm, and the depth (h) is limited in the scope of 5% to 50% the thickness of the vanes. The phiand h of the dimples (g) may be arranged in the grid form, a zigzag form, or an irregular form. Consequently, an exfoliation of the airflow on the lower pressure surface sides of the vanes can be reduced, and a pressure variation following the exfoliation can be reduced. A lower noise effect lower than the conventional impeller is realized consequently.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a technique for reducing noise of a blower.

BACKGROUND ART A conventional blower has a structure as shown in FIG. 7, as shown in, for example, Japanese Unexamined Patent Publication No. 1-96498. As a blower, this impeller a is housed in a suitable casing and rotated in the direction of the arrow to generate the air blowing action. The impeller rotates with the motor shaft fixed to the impeller boss e. - Also, in Fig. 7a, which is a perspective view of this blower, the cut plane on the warp line of the blade has a simple structure as shown in Fig. 7. The structure of the blower (further improvement is required to reduce noise).

General ζmi One of the noises generated from blowers is thought to be the separation of the flow from the low-pressure surface of the blades, which causes pressure fluctuations. The present invention aims to improve this problem and achieve noise reduction.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention includes a plurality of blades around a hub, and a plurality of approximately circular dimples on the low pressure side of the blades. .

action The effects of the above means are as follows.

Reduces multiple large approximately circular flakes on the low-pressure side of the blower blade. This reduces pressure fluctuations associated with peeling and achieves even lower noise.

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

Here, we will explain the application to a mixed flow blower as an example.

Figures 1 and 2 illustrate a first embodiment of the present invention.

Fig. 1a It is a perspective view of the blower impeller @ Fig. 1 is a cross-sectional view of the impeller along the warp line.

Impeller a 11 A substantially truncated conical hub portion f is provided with blades. A plurality of approximately circular dimples g are provided on the low pressure side of the blade.

Fix the motor shaft to the impeller boss part e and place it in an appropriate casing.The motor will flow out in the direction of the arrow d.

At this time, the dimple g reduces flow separation on the low-pressure surface side of the blade, and as a result, pressure fluctuations due to separation are reduced, resulting in an even lower noise effect. As shown in Figure 2 (l:, φ360mm mixed flow impeller (number of blades: 4)
Experimental data on air volume and noise with an orifice inner diameter of 372 mm indicates a low noise level of about 0.5 dB.Also, the noise spectrum shows a range of about 200H2 to about 2500H2.
The sound pressure level has decreased in a wide frequency range of Hz.

FIG. 3 explains the second technical means of the present invention.

In Fig. 3, φ indicates the representative dimension of the approximately circular dimple g (for example, the length of the direct fine if it is a circle, or the length of the major axis if it is an ellipse).
, , h indicates the depth of the dimple g. Here, φ
is 1 mm to 20 mm, and h is limited to a dimple size within a range of 5% to 50% of the thickness of the blade. In addition to reducing the separation of the flow from the low-pressure side b' of the blade and having a low noise effect (similar to the first embodiment), there is no problem with the blade's resistance to strong impact. Note again
It increases the degree of freedom in manufacturing and can also contribute to productivity and cost reduction.

FIG. 4 is a plan view of the impeller described regarding the third technical means of the present invention.

In other words, the dimples g are irregularly arranged on the low-pressure surface side b' of the blade, with the representative dimensions φ and depth h of the dimples varied within the range shown in the second technical means mentioned above. be.

If irregularities are created in both the size and arrangement of the dimples g in this arrangement, the lower pressure side b of the blade will be larger than in the first embodiment.
This makes it possible to control peeling more than 100 cm, and has an even further low noise effect.

Fig. 5a, bl;j is a plan view of the impeller described in relation to the fourth technical means of the present invention.

Low-pressure side b'cQ of the blade Within the dimple size range described in the second technical means, dimples g of the same size are arranged in a lattice pattern (Fig. 4a), and dimples arranged in a zigzag pattern are used. (Figure 4b).

Even in such a shape and arrangement of dimples g, the first
In addition to being able to prevent separation of the flow from the low-pressure surface side b of the blade, the arrangement is regular, making it easy to manufacture and reducing production costs.

FIG. 6 is a plan view of the impeller described regarding the fifth technical means of the present invention.

This (toward the low pressure side b' of the blade) dimples g of the same size are arranged irregularly within the dimple size range described in the second technical means. By creating irregularities in the blade, it is possible to control the separation of the flow from the low-pressure side b of the blade more than in the first embodiment, and to have an even more low noise effect, which is even more effective than the manufacturing invention. Thus, the blower impeller of the present invention has a plurality of blades around the hub, and a plurality of approximately circular dimples are provided on the low-pressure side of the blade. Separation of flow on the low-pressure surface of the blade can be reduced.This reduces pressure fluctuations caused by separation, resulting in a lower noise effect than in the past.

[Brief explanation of drawings]

FIG. 1(-a) is a perspective view of the blower impeller according to the first embodiment of the present invention. FIG. 1(-b) is a perspective view of the blower impeller according to the first embodiment of the present invention. Cross-sectional view Figure 2 shows the same transsonal characteristic@, Figure 3 shows the second embodiment of the present invention, Figure 4 shows the third flat surface of the present invention, Figure 6 shows the fifth embodiment of the present invention. The principal parts of the blower impeller according to the embodiment are shown in FIG. a... Feather handle b... Feather maple C... Leading edge
d... Revenge... Impeller boss starvation f...
Hub Kg...Ding/k b"...Low pressure surface of the blade (KL b"...High pressure surface of the blade L φ
...Representative size? & h...depth.

Claims (5)

[Claims] (1) A blower impeller including a plurality of blades around a hub, and a plurality of approximately circular dimples provided at a predetermined density on the low-pressure side of the blades. (2) A claim in which the approximately circular dimple provided on the low-pressure surface side of the blade has a typical dimension of 1 mm to 20 mm, and the depth of the dimple has a shape of 5% to 50% of the thickness of the blade. The blower impeller according to item 1. (3) The blower impeller according to claim 1, wherein the representative dimensions and depths of the dimples are varied and the dimples of various dimensions are irregularly arranged on the low pressure surface side of the blade. (4) The blower impeller according to claim 2, wherein dimples of the same size are arranged on the low-pressure side of the blade in a lattice or zigzag pattern. (5) The blower impeller according to claim 2, wherein the dimples of the same size are arranged irregularly on the low pressure side of the blade.