JPH1039875A - Sound insulating material structure and soundproof structure of air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the frequency at which the change in the cavity volume by recessed parts is suppressed and a sound reduction effect is expected even when the material is used in a curved state at an initial state and to obtain a stable noise decreasing effect by specifying the number of the communicating holes of a sound insulating layer formed to be communicated with the cavities by the recessed parts of a sound insulating material to >=2. SOLUTION: The many recessed parts 111 of a prescribed depth for forming the cavities are formed on the surface of the sound insulating material body 11. The sound insulating layer 12 is laminated on the surface of the sound insulating material body 11. The plural communicating holes 121 communicating the cavities formed by the recessed parts 111 with respect to the recessed parts 111 of the sound insulating material body 11 are formed in this sound insulating layer 12. In such a case, the cavity volume V for determining the prescribed resonance frequency f and the ratio S/l of the area and the length by the communicating holes 121 are determined and the total sum area S of these communicating holes 121 is made coincident with the area by the single communicating hole for obtaining the prescribed resonance frequency f. Namely, the area for obtaining the prescribed resonance frequency f is assured by forming a plurality of the slender communicating holes 121.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound insulating material used for an air conditioner and the like and a sound insulating structure of the air conditioner.

[0002]

2. Description of the Related Art Conventionally, as an air conditioner, as shown in FIG. 8, a heat exchanger 2 and a blower 3 are arranged inside a housing 1, and a compressor is separated from the heat exchanger 2 and the blower 3. In such a configuration, for the purpose of isolating the noise generated from the compressor 4, the outer periphery of the compressor 4 is covered, and the sound insulating material 5 is provided on the inner surface of the housing 1 near the compressor 4. There is something.

[0003] However, in such a structure, although the noise generated from the compressor 4 can be expected to have a certain effect by the sound insulating material 5 by the sound insulating material 5, at present the surrounding consciousness of the noise is increasing. Not enough.

[0004] In particular, in a variable speed driven compressor that has recently been widely used, it is known that the electromagnetic noise generated remarkably only at a specific frequency driven by an inverter is generated. However, it is a big problem such as being harsh.

[0005] In addition, the adoption of a new refrigerant has been promoted due to environmental problems. However, with the adoption of the new refrigerant, the refrigerant pressure during the operation of the compressor tends to increase, so that fluid noise is likely to be generated. This resonates in the volume in the compressor and the refrigerant piping system, and noise of a resonance frequency is protruded and generated, and this noise has also been a major cause of annoyance.

Therefore, a sound insulating material configured as disclosed in JP-A-59-52299 has been proposed. FIGS. 9 and 10 show a schematic configuration of such a sound insulating material 5. The sound insulating material main body 6 having a concave portion 61 having a predetermined depth is shown.
On the other hand, a sound insulation layer 7 having a communication hole 71 communicating with the concave portion 61 of the sound insulation material main body 6 is laminated to obtain sound insulation using so-called Helmholtz type resonance.

Here, Helmholtz-type resonance can obtain a large noise reduction effect at a frequency f expressed by the following equation. f = c / (2π) · (C0 / V) 1/2 where, c; speed of sound, a; diameter of the communication hole 71, the length of the communication hole 71, V; cavity by the recess 61 volume, C0 =? pa ² /
(L + πa / 2).

Accordingly, in the air conditioner, for the noise of a frequency which is particularly problematic, the structure of the above-mentioned sound insulating material 5, that is, the cavity volume V by the concave portion 61, the communication with the frequency f of the above equation is adjusted so as to correspond to the above-mentioned frequency f. If the diameter a and the length L of the hole 71 are set, a large noise reduction effect on noise can be expected.

[0009]

However, according to the sound insulating material 5 configured as described above, as shown in FIG. 8, the sound insulating material 5 covers the outer periphery of the compressor 4 or is provided on the inner surface of the housing 1, so that the whole is curved. In such a case, the frequency f at which the sound reduction effect can be expected may fluctuate. That is, FIG.
When the sound-insulating material body 6 and the sound-insulating layer 7 are curved as shown in FIG. 1, the sound-insulating layer 7 is greatly expanded and deformed as shown by the broken line in the figure because the opening diameter of the communication hole 71 corresponding to the recess 61 is large. However, since the cavity volume of the concave portion 61 changes from the original volume, the frequency f at which the sound reduction effect can be expected may fluctuate.

For this reason, it is conceivable to partially change the cavity capacity in advance in consideration of frequency fluctuations. However, in this case, the sound insulation material 5 is individually designed for each compressor and air conditioner. Therefore, there is a problem that the sound insulating material 5 has low commonality and is expensive. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sound insulating material structure and a soundproofing structure of an air conditioner that can expect a stable noise reduction effect.

[0011]

According to the first aspect of the present invention,
A cavity is formed by providing a concave portion of a predetermined depth on one surface of the sound insulating material, and at least two cavities communicating with the cavity are formed on the surface.
A sound insulation layer having the above communication holes is laminated.

According to a second aspect of the present invention, in the first aspect, a sound absorbing layer made of a porous material is mounted on the surface of the sound insulating layer. According to a third aspect of the present invention, in the second aspect, the porous material is made of an open-cell foam.

According to a fourth aspect of the present invention, in the first aspect, a reinforcing portion for preventing deformation is provided in the cavity. According to a fifth aspect of the present invention, a cavity is formed by providing a concave portion having a predetermined depth on one surface of the sound insulating material, and a sound insulating layer having at least two or more communication holes communicating with the cavity is laminated on the surface. The outer periphery of the compressor is covered by the sound insulation material.

According to a sixth aspect of the present invention, there is provided a sound insulating layer in which a concave portion having a predetermined depth is provided on one surface of a sound insulating material to form a cavity, and the surface has at least two or more communication holes communicating with the cavity. Are attached to the inner surface of the housing that houses the noise-generating device.

As a result, according to the present invention, by providing at least two or more communication holes in the sound insulation layer formed so as to communicate with the cavity formed by the concave portion of the sound insulation material, if the sound insulation material is used in a curved state, However, since the extent to which the opening of the communication hole is widened and deformed can be kept small, the change in the cavity volume due to the concave portion is suppressed, and the frequency at which the noise reduction effect can be expected is maintained in the initial state, and stable noise reduction The effect can be expected, and since the contact resistance with air can be increased by two or more communication holes, a large volume reduction can be obtained in a wide frequency range. Especially, even if the resonance frequency is slightly shifted, the noise reduction effect can be obtained. Can be expected to have a stable noise reduction effect on noise in a wide frequency range without abrupt reduction.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 and 2 show a schematic configuration of a sound insulating material structure to which the present invention is applied. In the figure, 1
Reference numeral 1 denotes a sound insulating material main body, and on the surface of the sound insulating material main body 11, a large number of concave portions 111 having a predetermined depth forming a cavity are formed.

The sound insulating layer 1 is formed on the surface of the sound insulating material main body 11.
2 are stacked. The sound insulation layer 12 is provided on the sound insulation material main body 11.
A plurality of (three in the illustrated example) communicating holes 121 communicating with the cavity formed by the concave portion 111 is formed in the concave portion 111.

In this case, in order to determine the predetermined resonance frequency f, the cavity volume V and the ratio S / l (= C0) of the area to the length of the communication hole 121 are determined. 121 is composed of a plurality of parts, and if the area of each communication hole 121 is Si, the total sum S of the areas of these communication holes 121 is:

[0019]

(Equation 1) The total area S is made equal to the area of a single communication hole for obtaining a predetermined resonance frequency f. That is,
By providing a plurality of elongated communication holes 121, an area for obtaining a predetermined resonance frequency f is secured.

The sound insulation material structure thus configured covers the outer periphery of the compressor 4 in the same manner as described with reference to FIG. 8, and is provided on the inner surface of the air conditioner housing 1 in which the compressor 4 is housed. I have to.

According to the sound insulating material structure described above, when the outer periphery of the compressor 4 is covered or provided on the inner surface of the housing 1 as described above, the entire sound insulating material structure may be curved. However, in this case, since the plurality of communication holes 121 formed in the sound insulating layer 12 have a small opening diameter, the opening of the communication hole is widened by bending and deformed as compared with a conventional communication hole having a large opening diameter. The frequency f at which the cavity volume due to the concave portion 111 does not change from the original volume can be suppressed, and the frequency f at which the sound reduction effect can be expected is maintained in the initial state.
A stable noise reduction effect can be expected.

Further, when the communication holes 121 of the sound insulation layer 12 are provided in a plurality, for example, when n communication holes 121 having the same area are provided, the area Si of each communication hole 121 is Si = S / n.
Therefore, the radius Ri is ri = r / n1 / ² with respect to the radius r of the single communication hole. In this case, the communication hole 121
Is larger as the contact resistance between the air and the wall surface of the hole becomes larger. Therefore, if there are a plurality of communication holes 121, then a single communication hole is obtained from n · 2πri · l = n1 ^{/ 2} · 2πr · l. In this case, n ^{1/2 is obtained} , the resistance of air by the plurality of communication holes 121 is increased, and the noise reduction effect on noise is improved.

That is, the noise reduction volume ΔP at this time is as follows: the volume of the cavity is V, the length of the communication hole 121 is 1;
1 is S, sound velocity is c, acoustic impedance is Z, air resistance at the communication hole 121 is R, frequency is f, and Helmholtz resonance frequency fr = c / 2π · (S / Vl).
^{Then, 1/2} is given by the following equation.

[0024]

(Equation 2)

FIG. 3A shows this equation.
It becomes as shown in. In this case, in the related art, a large sound reduction is obtained only at the resonance frequency fr as shown in FIG. 2B, whereas in FIG. 2A, the sound reduction effect at the resonance frequency fr is slightly reduced. This makes it possible to obtain a large volume reduction over a wide frequency range, thereby eliminating the inconvenience that the noise reduction effect drops sharply even when the frequency slightly deviates from the resonance frequency fr. A stable noise reduction effect on noise can be expected in the range. (Second Embodiment) FIG. 4 shows a second embodiment of the present invention, and the same parts as those in FIG.

In this case, on the surface of the sound insulating material main body 11 in which a large number of concave portions 111 having a predetermined depth for forming a cavity are formed, the concave portions 11 are formed.
A sound insulation layer 12 having a plurality of communication holes 121 communicating with the cavity formed by the first layer 1 is laminated, and a sound absorption layer 13 is provided on the surface of the sound insulation layer 12. This sound absorbing layer 13
Uses a porous material made of an open-cell foam material.

In this way, a more stable noise reduction effect can be expected due to the effect of further laminating the sound absorbing layer 13 on the above-described Helmholtz type resonance structure. (Third Embodiment) FIGS. 5 and 6 show a third embodiment of the present invention, and the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

In this case, a cylindrical reinforcing member 14 is provided on the bottom surface of the concave portion 111 having a predetermined depth formed on the surface of the sound insulating material main body 11.
When the sound insulating layer 12 having a plurality of communication holes 121 communicating with the cavity formed by the concave portion 111 is laminated on the surface of the sound insulating material main body 11, the tip of the reinforcing member 14 is attached to the sound insulating layer 1.
By contacting the two surfaces, the cavity formed by the concave portion 111 is prevented from being deformed.

In this manner, the reinforcing structure of the reinforcing member 14 can prevent the cavity from being deformed due to the deformation around the communication hole 121 of the sound insulating layer 12, and can prevent the fluctuation of the frequency at which the noise reduction effect can be expected.

In this embodiment, the reinforcing member 14
Is a columnar shape, but is not limited to this shape as long as the purpose of preventing deformation of the cavity formed by the concave portion 111 is achieved, and various shapes are possible. (Fourth Embodiment) FIG. 7 shows a fourth embodiment of the present invention, in which a compressor 21 is supported by a vibration isolator 22 in a vibration-proof manner.

In this case, as in the case of FIG. 1, the vibration isolator 22 has a recess 11 having a predetermined depth on one surface of the main body 11 of the sound insulating material.
1 to form a cavity, on the surface of which is laminated a sound insulation layer 12 having at least two or more communication holes 121 communicating with the cavity. And mounts and supports the compressor 21 and further attaches the vibration isolator 22 to the fixture 23.
To fix to the fixing member. Where 2
Reference numeral 11 denotes a discharge pipe of the compressor 21, and reference numeral 212 denotes a suction pipe of the compressor 21.

With this structure, the vibration isolator 22 for supporting the compressor 21 in a vibration-isolating manner has a sound-insulating material structure, so that the noise generated from the compressor 21 as well as the vibration can be reduced, and the installation can be further reduced. Can also be done easily.

In this embodiment, an example is described in which the sound insulating material structure described in the first embodiment is used as the vibration isolator 22, but the sound insulating material structure described in the second or third embodiment is used. Can also be used.

[0034]

As described above, according to the present invention, by providing at least two or more communication holes in the sound insulating layer formed so as to communicate with the cavity formed by the concave portion of the sound insulating material,
Even when used in a curved state, the extent to which the opening of the communication hole is widened and deformed can be kept small, so that the change in the cavity volume due to the concave part is suppressed, and the frequency at which the sound reduction effect can be expected is maintained in the original state. As a result, a stable noise reduction effect can be expected, and since the contact resistance with air can be increased by two or more communication holes, a large volume reduction can be obtained in a wide frequency range, and in particular, it is slightly shifted from the resonance frequency. Even in such a case, a stable noise reduction effect on noise can be expected in a wide frequency range without the noise reduction effect sharply decreasing.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of the first embodiment.

FIG. 3 is a diagram for explaining the operation of the first embodiment.

FIG. 4 is a sectional view showing a schematic configuration of a second embodiment of the present invention.

FIG. 5 is an exploded perspective view showing a schematic configuration of a third embodiment of the present invention.

FIG. 6 is a sectional view showing a schematic configuration of a third embodiment.

FIG. 7 is a sectional view showing a schematic configuration of a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a schematic configuration of a conventional air conditioner.

FIG. 9 is an exploded perspective view showing a schematic configuration of a conventional sound insulating material.

FIG. 10 is a sectional view showing a schematic configuration of the conventional sound insulating material.

FIG. 11 is a view for explaining a curved state of the conventional sound insulating material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Sound insulation material main body, 111 ... recessed part, 12 ... Sound insulation layer, 121 ... Communication hole, 13 ... Sound absorption layer, 14 ... Reinforcement member, 21 ... Compressor, 22 ... Vibration isolator, 23 ... Mounting fixture.

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[Procedure amendment]

[Submission date] September 12, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

Here, Helmholtz-type resonance can obtain a large noise reduction effect at a frequency f expressed by the following equation. f = c / (2π) · (C0 / V) 1/2 C0 = πa 2 / (L + πa / 2) where, c; speed of sound, a; diameter of the communication hole 71, L; communication hole 7
1 of length, V; a cavity volume product from the recess 61.

Claims (6)

[Claims] 1. A sound insulating material comprising a concave portion having a predetermined depth on one surface to form a cavity, and a sound insulating layer having at least two or more communication holes communicating with the cavity is laminated on the surface. Sound insulation material structure characterized by the following. 2. The sound insulating material structure according to claim 1, wherein a sound absorbing layer made of a porous material is mounted on the surface of the sound insulating layer. 3. The sound insulation material structure according to claim 2, wherein said porous material is made of a foamed material of a continuous foam material. 4. The sound insulating material structure according to claim 1, wherein a reinforcing portion for preventing the deformation is provided in the cavity. 5. A sound insulating material comprising: forming a cavity by providing a concave portion having a predetermined depth on one surface of a sound insulating material; and laminating a sound insulating layer having at least two or more communication holes communicating with the cavity on the surface. A soundproof structure for an air conditioner, wherein the outer periphery of the compressor is covered with a material. 6. A sound insulating material comprising a concave portion having a predetermined depth provided on one surface of a sound insulating material to form a cavity, and a sound insulating layer having at least two or more communication holes communicating with the cavity is laminated on the surface. A soundproof structure for an air conditioner, wherein a material is attached to an inner surface of a housing containing a device that emits noise.