JPH01169195A - Silencer - Google Patents

Abstract

PURPOSE:To obtain a silencing effect for a predetermined noise by forming a resonance chamber by laminating two or more blocks and changing the characteristic of resonance frequency to be silenced by changing a quantity of the laminated blocks. CONSTITUTION:A cylindrical external wall 2 is provided for a cylindrical internal wall 1 forming a wind tunnel 5 in the center part, and by forming a side plate 6 in one side surface, a block 9 is constituted. Further by providing packings 7A and 7B to be interposed, an opening part 9A in the other side surface of the block 9 is adapted to a side end surface 8A of a member 8, and a resonance chamber 3 is formed. While providing partitions 9B in the resonance chamber 3 and dividing it into two or more resonance chamber 3, the respective resonance chamber 3 communicates with the wind tunnel 5 through a communication hole 4 provided in the internal wall 1.

Description

[Detailed Description of the Invention] [Summary] A resonance chamber is formed around the outer periphery of a wind tunnel that guides air through a cylindrical side wall, and the noise sent into the wind tunnel is muffled by communicating the wind tunnel with the resonance chamber. With regard to silencers, the purpose of which is to form multiple resonance chambers by stacking blocks and improve the silencing characteristics against a certain amount of noise, by providing a side plate on one side of the inner and outer walls. A resonance chamber is constructed by bringing the opening on the other side of the block into contact with the side end face of a predetermined member, and packing is provided at the tips of each of the inner wall and the outer wall that come into contact with the side end face. The system is configured so that

[Industrial application field]

The present invention relates to a muffler that forms a resonance chamber around the outer periphery of a wind tunnel that guides air through a cylindrical side wall, and that communicates the wind tunnel with the resonance chamber to muffle the noise that is sent into the wind tunnel.

In an electronic device, the heat generated by the internally installed electronic equipment is cooled by air cooling, which takes outside air into the device into a membrane and exhausts the taken air outside the device.

A blower is normally used to blow the air, and the blower is driven.

However, since noise is generated when these blowers are driven, especially when these electronic devices are installed in general offices, etc., it is necessary to use highly silencing devices to reduce the lateral force of such noise. A silencer is requested.

[Conventional technology]

Conventionally, the configuration was as shown in the conventional explanatory diagram of FIG. Figure 3 (a) is a side sectional view, (b) is the attenuation in dB
It is a relationship graph between and resonance frequency f.

As shown in FIG. 3(a), a blower 10 is locked at one end, and the air sent out from the blower 10 is sent out from the other end as shown by arrow A into a duct 11 forming a wind tunnel 13. Boxes 15A and 15B form the resonance chamber 14.

15G, each resonance chamber 14 is configured to communicate with the wind tunnel 13 via a through hole 12 provided in the side wall 11A of the duct 11, and each box 15A.

The volume of the hollow resonance chamber 14 formed in 15B and 15G is Vl.

V2. It is formed differently like V3.

Therefore, the noise passing through the wind tunnel 13 is attenuated according to the resonance frequency f formed by the unique frequency of the resonance chamber 14.

In this case, the resonance frequency f is expressed by equation (1), where the speed of sound at room temperature is C, the volume of the resonance chamber 14 is V, the cross-sectional area of the communication hole 12 is S, and the length of the communication hole 12 is l. Can be done.

Therefore, as shown in (c), for example, in order to obtain the attenuation value of a predetermined silencing characteristic, for example, the point P1 of the resonance frequency f due to the volume v1 and the point P2 of the resonance frequency f due to the volume v2 are required. resonance frequency f due to the location and volume v3,
It is possible to obtain a predetermined sound silencing effect corresponding to each of the P3 locations.

[Problem that the invention seeks to solve]

In such a configuration, by analyzing the noise, the frequency range of the noise in Hz to be silenced is estimated in advance, and the frequency range of the noise in Hz is
The volumes of the resonance chamber 14 according to Vl, V2. Setting V3 is performed.

However, when configured as described above to actually perform noise reduction, the frequency of the noise in Hz often deviates from a predetermined value.

Therefore, a deviation occurs from the resonance frequency f due to the resonance chamber 14, and a predetermined silencing characteristic cannot be obtained, so that the volume is reduced to V.
l, V2. To change V3, Box 15A, 1
There was a problem that required changes to 5B and 15C.

Therefore, an object of the present invention is to form a plurality of resonance chambers by stacking blocks and to improve the silencing characteristics against a predetermined noise.

[Means for solving problems]

FIG. 1 is a sectional view showing the principle of the present invention.

As shown in Figure 1, a resonance chamber is constructed by bringing the opening on the other side of the block formed by providing a side plate on one side of the inner wall and the outer wall into contact with the side end face of a predetermined member. At the same time, banking is provided at the tips of each of the inner wall and the outer wall that come into contact with the side end surface.

With this configuration, the above-mentioned problems are solved.

[Effect]

That is, a resonance chamber communicating with a wind tunnel through which noise is transmitted can be easily formed by stacking blocks on predetermined side end surfaces.

Therefore, by stacking a plurality of blocks to form many resonance chambers and changing the characteristics of the resonance frequency f, a predetermined silencing characteristic can be obtained. It is possible to prevent the silencing characteristics from deteriorating due to the deviation.

〔Example〕

The present invention will be explained in detail below with reference to FIG.

FIG. 2 is an explanatory diagram of an embodiment according to the present invention; (a) is a side view, (b) is a sectional view, (C) is a side sectional view, and (d) is a graph of the relationship between attenuation amount dB and frequency. be.

As shown in FIG. 2(a), a cylindrical outer wall 2 is provided for a cylindrical inner wall 1 in which a wind tunnel 5 is formed in the center, and a side plate 6 is formed on one side of the block 9. Further, the resonance chamber 3 is formed by the opening 9A on the other side of the block 9 coming into contact with the side surface of the member 8 with the packings 7A and 7B interposed therebetween. It is something.

In this case, the packings 7A and 7B must be made of a vibration-proof rubber material to seal the resonance chamber 3 and to prevent vibrations from being transmitted to the contact surfaces.

Also, in the resonance chamber 3, there is a sectional view of B-8 in (a).
As shown, a partition 9B is provided to divide the resonance chamber 3 into a plurality of resonance chambers 3, and each resonance chamber 3 is communicated with the wind tunnel 5 through a communication hole 4 provided in the inner wall 1.

Therefore, as shown in (c), the inner wall 20D and the outer wall 20
The blocks 9-1 to 9-4 can be formed so as to be stacked on top of each other by using packings 7A and 7B, respectively, on the sound deadening block 20 in which a resonance chamber 20B is formed by the side plate 20F and the side plate 20F.

In this case, a plurality of resonance chambers 3-1 to 3-4 are formed by stacking blocks 9-1 to 9-4.

When a plurality of resonance chambers 3-1 to 3-4 are formed in this way, the resonance frequency fp becomes as shown in (d,),
A wide resonance frequency f, so that a predetermined attenuation amount can be obtained even if the resonance frequency fp is in the range of 01 to C2.
A silencing effect can be obtained for.

Therefore, depending on the actual noise content, block 9-1
~9-4 can be increased or decreased to obtain the most effective condition.

In this case, the hooks 208 and 90 are attached to the sound deadening block 20 at the bottom and the block 9-4 at the top, respectively.
If a clamp 21 such as a rubber string or a spring is stretched between the hook 2OA and the hook 90, the stacking of the blocks 9-1 to 9-4 can be easily increased or decreased, and noise can be reduced. The resonant frequency f can be adjusted freely according to the content of
It becomes possible to freely adjust p, and a predetermined silencing characteristic can be obtained.

In the explanation of the present invention, the resonance chamber 3 is illustrated as being divided into four parts, but it is not necessary to divide it into four parts, and even if it is divided into two parts, the same effect can be obtained.

〔Effect of the invention〕

As explained above, the present invention forms a resonant chamber by stacking a plurality of blocks, and by changing the number of stacked blocks, the characteristics of the resonance frequency to be muted are varied, thereby achieving a silencing effect on a predetermined noise. Therefore, it is possible to prevent the resonant frequency of the resonant chamber from shifting with respect to the actual noise and deterioration of the silencing characteristics as in the past, and furthermore, it is possible to prevent the resonance frequency of the resonant chamber from shifting with respect to the actual noise and deterioration of the silencing characteristics. Even in such cases, the sound can be muffled by increasing the number of resonance chambers, the muffling characteristics can be improved, and the practical effect is great.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the principle of the present invention. FIG. 2 is an explanatory diagram of an embodiment according to the present invention, in which (a) is a side view, (b) is a sectional view, and (C) is a side sectional view. (d) is a graph of the relationship between attenuation amount dB and frequency. FIG. 3 is a conventional explanatory diagram, and (a) is a side sectional view. (b) shows a graph of the relationship between the attenuation amount dB and the resonance frequency fp. In the figure, 1 is the inner wall and 2 is the outer wall. 3 is the resonance chamber, 4 is the communication hole. 5 is the wind tunnel, 6 is the side plate. 78, 7B is packing, 8 is parts.

Claims (1)

[Claims] A hollow resonance chamber (3) is formed between a cylindrical inner wall (1) and an outer wall (2), and a communication hole (4) is provided in the inner wall (1),
In a silencer that muffles noise sent to the wind tunnel (5) by communicating a wind tunnel (5) formed at the center of the inner wall (1) with the resonance chamber (3), the inner wall (1) ) and the outer wall (2), and the opening on the other side of the block (9) formed by providing a side plate (6) on one side is brought into contact with the side end surface (8A) of the predetermined member (8). By bringing them into contact with each other, the resonance chamber (3) is formed, and
The inner wall (1) and the outer wall (
2) Packing (7A, 7B) at each tip
A silencer characterized by being provided with.