JPS645117Y2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to the improvement of a wind tunnel for a blower, particularly a wind tunnel for a multi-blade blower having a short cylindrical casing.

(Prior Art) The content and structure of the prior art will be explained with reference to FIGS. 1 to 3.

Figures 1 a to d show a conventional multi-blade blower and its impeller. When the impeller 1 is rotated in the direction of the arrow, the air inside the blade is absorbed by the rotation of the impeller. Due to the centrifugal force caused by the centrifugal force, the air is guided inside the vortex of the casing 2 and is discharged from the casing 2 through the exhaust hole 4.The inside of the vane becomes a vacuum, and new air is taken in from the suction hole 3 of the casing 2 and flows into the exhaust hole 4. Air flows in the direction of arrows A, B, C, D, and E.

The general air volume characteristics of such a blower are that the wind pressure is proportional to the product of the diameter of the blade and the rotational speed, the air volume is proportional to the cross section of the suction hole and exhaust hole, and the general pressure - flow rate during operation at a certain speed As shown in FIG. 2a, the characteristic is a drooping characteristic in which the pressure gradually decreases as the flow rate increases.

However, the applications for blowers are diverse, and many applications require specific pressure-flow characteristics.
For example, the characteristics required of a blower for a magnetic disk drive device used as an external storage device for a computer are as shown in FIG. 2b, such as high pressure, small flow rate, and small change in flow rate due to changes in load resistance.

To obtain such characteristics, the diameter of the impeller is increased to increase the pressure, as shown in Figure 3 a to e, and the cross-sectional area of the impeller and the air flow path inside the casing, including the exhaust hole, is increased. It is sufficient to reduce the resistance and increase the resistance of the flow path.

In the blower shown in FIGS. 3a to 3e, if the wind tunnel 23 is not provided in the casing 22, the suction side will have a hole approximately equal to the inner diameter of the impeller 21, and if the blower is operated sideways, the static pressure will reach the desired value. , the flow rate becomes excessive, resulting in, for example, the characteristics shown in c in FIG.

Therefore, the wind tunnel 23 is provided so as to completely cover the suction side of the casing 22, and the cross-sectional area of the suction hole 23-1 is made smaller than the area surrounded by the inner circumference of the impeller 21.
Furthermore, it is conceivable that if the cross-sectional area of the exhaust hole 24 is made smaller than the cross-sectional area of the suction hole 23-1, the resistance of the flow path will increase and an increase in the flow rate can be prevented.
If the inside of 3 has a simple small cylindrical shape, the characteristics shown in b in FIG. 2 cannot be obtained, and only the characteristics shown in d in the same figure, for example, can be obtained.

The reason for this is that in order to achieve high pressure and low flow rate, the area of the exhaust hole 24 is smaller than the area of the suction hole 23 - as shown in Figure 3c.
1, the pressure Po near the exhaust hole of the impeller 21 becomes higher than the pressure Pi near the suction hole of the impeller 21, as shown in Fig. 3d.
This is because a short circuit occurs in the path of the arrow S through the wind tunnel 23 located on the entire surface of the blade, and the air blowing efficiency of the blades is extremely reduced.

(Problems to be Solved by the Invention) The aim of the present invention is to obtain a wind tunnel that can solve the problem of limiting air volume characteristics and reducing whistling noise due to the difference in pressure between the suction side and the discharge side in the wind tunnel.

(2) Structure of the invention (means for solving problems) The wind tunnel of the blower of the present invention has first to fifth wind tunnels arranged in a short cylindrical wind tunnel attached to the air suction side of the casing of a multi-blade blower. One end of each partition plate contacts the inside of the wind tunnel, the other end faces the side that contacts the casing, and one side of the first partition plate faces the arc-shaped part of the wind tunnel at a position opposite to the inlet. One side of the second to fifth partition plates is in contact with the arcuate inner surface of the wind tunnel at both sides of the inlet, and the other side of the first to third partition plates extends to the center of the wind tunnel. The fourth and fifth partition plates are characterized in that they touch each other, and the other sides of the fourth and fifth partition plates extend inward from the center of the wind tunnel to a position closer to the suction port and touch each other.

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

Figures 4a and 4b show an embodiment of the wind tunnel according to the present invention.

In Figure 4 a and b, 33 is a wind tunnel, 34, 3
5, 36, 37, and 38 are first to fifth partition plates disposed inside the wind tunnel 33 to prevent air short-circuiting, one end of each partition plate is in contact with the inside of the wind tunnel 33, and the other end is in contact with the casing 22. It faces the side 33-2 that comes into contact with.

Further, one side of the first partition plate 34 has a suction port 33-
1, one side of the second to fifth partition plates 35 to 38 are in contact with the arcuate inner surface of the wind tunnel 33 at positions on both sides of the suction port 33-1, respectively. ~Third partition plates 34-36
The other side extends to the center of the wind tunnel 33 and touches each other there, and the fourth and fifth partition plates 37 and 38 extend inward at an angle shallower than the angle toward the center of the wind tunnel 33 and touch each other.

Note that the fourth and fifth partition plates 37 and 38 may be curved in an arc shape.

Furthermore, the end surface 34-1 of the first partition plate 34 on the side of the surface 33-2 has a structure for adjusting flow characteristics and reducing whistle noise.
Its height is gradually reduced toward the center of the wind tunnel 33.

To explain the operation of the wind tunnel of the present invention shown in FIGS. enters the inside of the impeller 21, and the pressure rises to Po due to the centrifugal force of the impeller, but the third and fifth partition plates 36 and 38 prevent short circuit with the pressure Ps at the entrance of the wind tunnel, and the first partition The plate 34 prevents a short circuit between the pressures Po and Pi on both sides thereof, and the second and fourth partition plates 35 and 37 function to prevent a short circuit between the pressures Pi and Ps.

As mentioned above, in the present invention, the inside of the wind tunnel 33 is divided into four areas by the first to fifth partition plates 34 to 38, so the pressure is higher and the flow rate is smaller than in the case where such partition plates are not provided. It is possible to easily obtain characteristics such that the flow rate changes little with respect to load changes.

In addition, depending on the degree of inclination of the blade-side end surface 34-1 of the first partition plate 34, leakage between the pressures Po and Pi can be adjusted to adjust the flow rate characteristics and reduce whistling noise. second and third partition plates 35, 36, 37,
The space Q surrounded by 38 is located between the spaces Ps and Po or Pi, where there is a large pressure difference, and serves as an adjustment chamber to adjust the sudden pressure difference, which has the effect of reducing the whistling sound of the blades. be.

(3) Effects of the invention Since the wind tunnel of the invention has the above configuration,
This has the advantage of preventing short circuits due to pressure differences in the air flow in the wind tunnel, making it possible to adjust the flow rate, and reducing whistling noise caused by large pressure differences.

[Brief explanation of drawings]

Figure 1a is a front view of a conventional blower, Figure 1b is a side view, Figure 1c is a sectional view of its impeller, Figure 1d is a side view, and Figure 2 shows the flow rate and pressure. Characteristic diagram, Fig. 3a is a front view of another conventional blower, Fig. 3b is a side view thereof, Fig. 3c is an explanatory diagram of its exhaust hole, and Fig. 3d is a cross-sectional view of its impeller. , Figure 3e
is its side view, Figure 4a is the front view of the wind tunnel of the present invention,
FIG. 4b is a longitudinal sectional side view thereof. DESCRIPTION OF SYMBOLS 1... Impeller, 2... Casing, 3... Suction hole, 4... Exhaust hole, 5... Drive electric motor, 21...
...Impeller, 22...Casing, 23, 33...
Wind tunnel, 23-1, 33-1... Suction hole, 24...
Exhaust hole, 25... Drive motor, 33-2...
Surface, 34, 35, 36, 37, 38... partition plate,
34-1...End face.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A multi-blade blower having first to fifth partition plates disposed in a short cylindrical wind tunnel attached to the air suction side of the casing, one end of each partition plate. are in contact with the inside of the wind tunnel, the other end faces the side that contacts the casing, one side of the first partition plate is in contact with the arcuate inner surface of the wind tunnel at a position opposite to the suction port, and the second to fifth partitions One side of the plate is in contact with the arcuate inner surface of the wind tunnel at both sides of the inlet, the other sides of the first to third partition plates extend to the center of the wind tunnel and touch each other there, and the fourth and fifth partition plates are in contact with each other. A wind tunnel of a blower characterized in that the other side extends inward from the center of the wind tunnel to a position closer to the suction port and touches each other. (2) The wind tunnel of the blower according to claim 1, wherein the fourth and fifth partition plates have an arcuate shape from one side to the other side. (3) Utility model registration claim 1, characterized in that the height of the surface of the first partition plate that is joined to the casing of the blower is gradually lowered toward the center of the wind tunnel. Or a wind tunnel of the blower described in paragraph 2.