JP2001099092A - Multi-blades blowing fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict the wind noise, and increase the capacity in a multi-blades blowing fan. SOLUTION: Plural narrow and long blades 17 are integrally provided with the peripheral part of a support plate 1 with the predetermined space in the circumferential direction. A tip of each blade 17 is connected to each other through an auxiliary ring 9. Each blade 17 is formed so that a lower end thereof is fallen while displaced in the circumferential direction of the support plate 1 in relation to an upper end thereof, and twisted between the upper and the lower ends thereof.

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 fan, and more particularly to an improvement of a multi-blade blower fan for use in electronic equipment, electric equipment, an air conditioner, etc., which generates a wind by centrifugal force.

[0002]

2. Description of the Related Art Hitherto, as this kind of multi-blade blower fan, a configuration shown in FIGS. 9 and 10 is known.

That is, a central portion of a support plate 1 formed in a disk shape is curved and bulged, and a boss 5 is formed on the bulged portion 3 while an outer peripheral portion of the support plate 1 is formed along a circumferential direction. A plurality of elongated arc-shaped plate-shaped blades 7 are erected at predetermined arc intervals and arranged in an annular shape (only a part is shown in the figure; the same applies hereinafter). The upper ends of these blades 7 are connected by an auxiliary ring 9. Having a support plate 1
The blade 7 and the auxiliary ring 9 have been made into a product by being integrally molded with, for example, a polypropylene resin or the like.

[0004] The multi-blade fan is used by inserting a support hole 11 formed in a boss 5 into a shaft 15 of a motor 13 and rotating the shaft 15 to rotate the blade 7.
When the blade rotates, air is sucked in from the inner regions of the plurality of blades 7 arranged in an annular shape and discharged to the outer peripheral side of the blades 7 to form a centrifugal wind.

[0005]

However, in such a conventional multi-blade fan, the airflow that sucks air from the inner region of the plurality of blades 7 and discharges the air toward the outer periphery is
As shown in FIG. 11, air is cut off at the inner end 7 a of each blade 7, which is located in the longitudinal direction (axial direction) facing the inner region, and is sucked in the longitudinal direction (axial direction) facing the outer region. Since the air is discharged while cutting the air at the outer end 7b located at the position (1), there is a problem that the wind noise is loud.

In order to reduce the wind noise by lowering the rotation speed, there is a correlation that the reduction of the wind noise causes a decrease in the air volume. Therefore, it is necessary to maintain and increase the air volume while reducing the wind noise. Is difficult, and the improvement has been desired.

The inventors of the present invention have conducted intensive studies on the cause of the increase in the wind noise when the air volume is increased in the multi-blade blower fan. As shown in FIG. The present invention was completed by standing upright from the support plate 1 and finding that the wind noise was increased by the synergistic effect of the suction sound at the inner end 7a and the discharge sound at the outer end 7b.

The present invention has been made under such circumstances, and provides a multi-blade blower fan capable of suppressing the noise due to wind noise and increasing the air volume.

[0009]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a disk-shaped support plate which is rotated by a rotary drive shaft, and which has a predetermined shape along a circumferential direction near an outer periphery of the support plate. A plurality of blades erected at an arc interval and an auxiliary ring connecting the upper portions of the blades. In particular, the blade is formed by shifting the lower end of the blade in the circumferential direction with respect to the upper end thereof. ing.

In the present invention, the blade is preferably formed by twisting between the lower end and the upper end of the blade.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals are given to portions common to the conventional example.

FIGS. 1 and 2 are a plan view and a vertical half sectional view showing an embodiment of a multi-blade blower fan according to the present invention.

The disk-shaped support plate 1 is formed of a synthetic resin having a bulged portion 3 whose central portion is bulged so as to be curved, and a boss is provided at the central portion of the bulged portion. 5 are protrudingly provided.

The boss 5 of the support plate 1 has a motor 13
The support hole 11 into which the shaft 15 is inserted is formed through.

The cross section of the shaft 15 has a shape resembling, for example, a semicircle, and the cross section of the support hole 11 also has a shape corresponding to the shape, so that the rotation of the shaft 15 causes the support plate 1 to rotate. It has become.

On the outer peripheral portion of the support plate 1 on the same side as the bulging portion 3 in the bulging direction (the upper surface side in FIG. 2), a predetermined same arc interval is provided along the circumferential direction of the supporting plate 1. A plurality of elongated blades 17 are integrally erected without projecting or slightly projecting from the outer peripheral edge of the support plate 1.

Each of the blades 17 has the same arc plate shape in which the cross section intersecting in the longitudinal direction is formed in an arc shape, and is similarly arranged with the inner arc surface facing the adjacent blade 17. Each upper end is integrally connected by an auxiliary ring 9.

The auxiliary ring 9 connects the outside at each upper end of each blade 7 and is located outside the outer peripheral edge of the support plate 1, so that the inside of the auxiliary ring 9 overlaps the outer peripheral edge of the support plate 1. Alternatively, they are formed so as to be located outside the outer peripheral edge.

As shown in FIG. 3, each blade 17 is tilted so that the lower end 17c of the base of the support plate 1 is displaced in the circumferential direction of the support plate 1 with respect to the upper end 17d on the connection side with the auxiliary ring 9. Is formed. Reference numeral 17a in FIG. 3 denotes an inner end positioned in the vertical direction (axial direction) facing the inner region surrounded by each blade 7, and reference numeral 17b denotes an outer end.

Further, as shown in FIG. 4, each blade 17 has an inner end 17a and an outer end 17a on the lower end 17c side.
b and an imaginary line connecting the outer end 17 b and the rotation center of the support plate 1 to “θ1”,
When the angle between the virtual line connecting the inner end 17a and the outer end 17b on the d side and the virtual line connecting the outer end 17b and the center of rotation of the support plate 1 is “θ2”, the angle θ1 = angle θ
2 between the lower end 17c and the upper end 17d.

In other words, as shown in FIG. 4, the blade 17 of the present invention rotates the outer end 17b of the lower end 17c and the upper end 17d about the rotation center of the support plate 1 by an arbitrary angle θ4 in the rotation direction. The imaginary line connecting the outer end 17b of the upper end 17d thus formed and the imaginary vertical line in the axial direction shown in FIG. In addition,
Even if the angle θ4 is inclined in the reverse direction with respect to the rotation direction, it is considered that there is an effect of reducing the level of the wind noise.

The support plate 1, the blade 17 and the auxiliary ring 9 are provided on the inside of the support plate 1, the auxiliary ring 9 and a first mold (not shown) forming the blade 17. And a second mold forming the outside of the blade 17 is fitted,
Injection molding ABS resin, polypropylene resin, polycarbonate resin, polyphenylene sulfide resin, etc.
Using the twist angle of the blade 17 as a guide, the molded product is protruded by a release plate (not shown) to be commercialized.

Such a multi-blade fan has a motor 13
When the blade 17 is rotated by the rotation of the shaft 15, air is sucked from the inner region of the plurality of blades 17 arranged in an annular shape and discharged to the outer peripheral side of the blade 7, and the lower end 17 c and the upper end 17 d of the blade 17 are rotated. The air will be cut off such that the inner end 17a between them is twisted in a curve oblique to the rotation direction.

Therefore, when focusing on a specific fixed virtual rotation angle with respect to each blade 17, each blade 1
The portion where the lower end 17c and the upper end 17d of 7 intersect with the rotation angle is not a line but a point.

That is, as the blade 17 rotates, the point between the lower end 17c and the upper end 17d of each blade 17
It intersects so as to sequentially move from top to bottom (or from bottom to top) with respect to the specific rotation angle.

The rotation of the blade 17 makes it possible to cut off the air without any resistance, as compared with the conventional structure in which the blade 7 is erected in the vertical direction, and the space between the support plate 1 and the auxiliary ring 9 is reduced. , The length of the blade 17 can be made longer than in the conventional configuration.

As described above, in the multi-blade blower fan of the present invention,
A plurality of elongate blades 17 are integrally erected on the outer peripheral portion of the disc-shaped support plate 1 at predetermined arc intervals along the circumferential direction of the support plate 1, and the upper end 17 d of each blade 17 is provided.
Are integrally connected by the auxiliary ring 9 and the lower end 17 is
Each of the blades 17 is formed so that c is tilted in the circumferential direction of the support plate 1 with respect to the upper end 17d, and is formed by twisting between the lower end 17c and the upper end 17d. The air is cut so that the inner end 17a between the lower end 17c and the upper end 17d of the blade 17 is twisted in an oblique curve with respect to the rotation direction, so that the blade 17 can easily cut the air and suppress the generation of wind noise. Becomes possible.

Moreover, the noise is reduced by dispersing the wind noise by changing the wind breaking points of the inner end 17a and the outer end 17b in a stepwise manner in accordance with the rotation angle, instead of a line perpendicular to the support plate 1. Can be.

Further, even if the distance between the support plate 1 and the auxiliary ring 9 is fixed, the length of the blade 17 can be increased as compared with the conventional structure in which the blade 7 is erected in the vertical direction. There is an advantage that the amount of suction and the amount of discharge can be increased even by rotation, and the amount of air can be maintained and increased.

In order to confirm the effect of the multi-blade fan according to the present invention, the inventor has set the angle at which the blade 17 is tilted from the support plate 1 in the multi-blade fan according to the present invention to 15 degrees.
Comparison between the wind noise and the air volume between the conventional configuration (C) in which the product (A) of 5 ° and the product (B) of 5 ° are selected and the blade 7 is erected vertically from the support plate 1 is as follows. I went to.

FIGS. 5 to 7 show JIS Z8731 by rotating a product A having a configuration in which the blade 17 is tilted by 15 °, a product B having a configuration in which the blade 17 is tilted by 5 °, and a product C having a conventional configuration at 3000 rpm.
FIG. 5 is a measurement diagram showing the relationship between the frequency and the sound pressure of wind noise measured in a background noise chamber based on the noise level measurement method and the JISC1513 band analyzer.

According to this, the sound pressure around 800 Hz is high in any of the multi-blade blowers,
The sound pressure of z is 40.1 dB for product A and 47.
8 dB and 52.4 dB for the C product of the conventional configuration, and it can be seen that the level of the wind noise decreases as the angle at which the blade 17 is tilted increases. This is due to a change from a linear windbreak to a diagonal windbreak.

Further, when focusing on about 800 Hz, A
It can be seen that the product C and the product B gradually decrease, while the product C of the conventional configuration shows a prominent sound pressure level only around 800 Hz, which is annoying.
In other words, the unpleasant wind noise of the multi-blade fan of the present invention can be reduced.

FIG. 8 is a graph showing the air flow versus static pressure characteristics of the product A, the product B, and the product C of the conventional configuration.

According to FIG. 8, for example, a static pressure of 12 mm
Comparing the vicinity of Aq, it is 1.6 m ³ / mi for product A
n and B products are 1.45 m ³ / min, and the conventional product C is 1.3 m ³ / min.
It can be seen that the larger the angle of tilting the air, the larger the air volume.

However, in the multi-blade blower fan of the present invention,
Although the wind noise and wind pressure can be improved as the blade 17 is tilted at a larger angle, it is difficult to manufacture the blade 17 at a too large angle.

Further, in the present invention, the wind noise and the air volume can be improved to some extent only by tilting each blade 17 without twisting, but twisting is more preferable.

The auxiliary ring 9 connecting the blades 17 does not necessarily need to connect the upper end 17d of each blade 17, but may be an upper part.

[0039]

As described above, the present invention provides a disk-shaped support plate, and a plurality of blades standing upright at predetermined arc intervals along the circumferential direction near the outer periphery of the support plate.
An auxiliary ring for connecting the upper parts of these blades is provided. In particular, since the lower ends are shifted in the circumferential direction with respect to the upper ends, the blades are formed. Becomes possible. In the configuration in which the blade is formed so that the lower end side or the upper end side of the blade is twisted, the wind noise can be further reduced while the air volume can be increased.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a multi-blade blower fan according to the present invention.

FIG. 2 is a vertical half sectional view (half sectional view between II and II in FIG. 1) of the multi-blade fan of FIG.

FIG. 3 is a perspective view showing a main part of a blade of the multi-blade fan of FIG. 1;

FIG. 4 is a diagram illustrating blades of the multi-blade fan of FIG. 1;

FIG. 5 is a measurement diagram of wind noise with respect to frequency in the multi-blade blower fan of the present invention.

FIG. 6 is a measurement diagram of wind noise with respect to frequency in the multi-blade blower fan of the present invention.

FIG. 7 is a measurement diagram of wind noise with respect to frequency in a conventional multi-blade fan.

FIG. 8 is a characteristic diagram of air volume and static pressure in the present invention and a conventional multi-blade fan.

FIG. 9 is a plan view showing a conventional multi-blade fan.

10 is a vertical half sectional view (half sectional view taken along line X-X in FIG. 9) of the multi-blade fan of FIG. 9;

FIG. 11 is a perspective view of a main part showing the blades of the multi-blade fan of FIG. 9;

[Explanation of symbols]

 Reference Signs List 1 support plate 3 bulging portion 5 boss 7, 17 blade 7a, 17a inner end 7b, 17b outer end 9 auxiliary ring 11 support hole 13 motor 15 shaft 17c lower end 17d upper end

Claims (2)

[Claims] 1. A disk-shaped support plate rotated by a rotary drive shaft, a plurality of blades erected at predetermined arc intervals along a circumferential direction near an outer periphery of the support plate, and A multi-blade blower fan comprising: an auxiliary ring connecting an upper portion; and a blade formed by shifting a lower end of the blade in a circumferential direction with respect to an upper end of the multi-blade blower. 2. The multi-blade blower fan according to claim 1, wherein the blade is formed so as to twist between the lower end side and the upper end side.