JP7344665B2 - Ventilation opening structure - Google Patents

Description

The present invention provides a ventilation opening structure that takes into consideration not only indoor noise reduction but also outdoor noise reduction in the surrounding environment.

Until now, the inventor has described a method for reducing noise propagation from ventilation openings provided in a building using a long slit resonator, for example, in Patent Document 1 (Japanese Patent Application Laid-open No. 2017-101530). As a noise reduction structure that reduces noise from ventilation openings, we proposed arranging resonators having slit-shaped openings in pairs to face each other on the interior wall where the ventilation openings are provided. .
Japanese Patent Application Publication No. 2017-101530

In the noise reduction method using a resonator described in Patent Document 1, a large noise reduction effect can be obtained at frequencies close to the resonance frequency determined by the cross-sectional shape of the resonator having slits (also referred to as "slit resonator"). On the other hand, there is a problem that the frequency range in which the noise reduction effect can be obtained is narrow, and almost no effect can be obtained at frequencies far from the resonance frequency. Such a problem becomes particularly noticeable when attempting to reduce noise having components in a wide frequency range, such as road noise.

In order to solve such a problem, the invention described in Patent Document 1 proposes an embodiment in which a sound absorbing material is incorporated together with a slit resonator, with reference to FIG. Porous sound-absorbing materials such as glass wool and polyester sound-absorbing materials are often used as sound-absorbing materials, and generally porous sound-absorbing materials exhibit a large sound-absorbing effect in high frequency ranges.

Therefore, by designing the slit resonator so that the resonant frequency is a low frequency at which it is difficult to obtain the effect of sound absorbing materials, it is possible to expect a noise reduction effect over a wide frequency band by complementing the two. However, when using a slit resonator and a sound absorbing material in combination, no guidelines have been provided so far on how to set their positional relationship to be effective, which is a problem.

The present invention solves the above-mentioned problems, and the ventilation opening structure according to the present invention includes a resonator provided in an inner wall of an opening of a building, and a resonator having a slit-like opening; and a sound absorbing material provided adjacent to the ventilating opening structure, the space surrounded by the inner wall functioning as a ventilation path, and the slit-shaped opening formed on one side of the casing constituting the resonator. The sound-absorbing material is disposed closer to the sound source than the resonator so that the one surface of the resonator and the surface of the sound-absorbing material are flush with each other to form a ventilation path without a step difference . The sound-absorbing material is characterized in that it exhibits a sound-absorbing effect at frequencies apart from the resonant frequency of the resonator .

Further, the ventilation opening structure according to the present invention is characterized in that the resonators are arranged in pairs so that the slit-shaped openings face each other.

Further, the ventilation opening structure according to the present invention is characterized in that it includes a plurality of the resonators adjacent to each other , and the sound absorbing material is arranged closer to the sound source than all the resonators.

Further, the ventilation opening structure according to the present invention is characterized in that the resonator has an air layer.

In the ventilation opening structure according to the present invention, the sound absorbing material is flush with the resonator and is placed closer to the sound source than the resonator. Compared to the case where the resonator is placed on the sound receiving side, the noise re-radiated from the ventilation opening structure can be reduced, and the noise in the entire environment including the surrounding area can be reduced.

It is a figure explaining the resonator 10 used for the ventilation opening structure 100 based on embodiment of this invention. FIG. 1 is a diagram illustrating a ventilation opening structure 100 according to an embodiment of the present invention. (A) is a diagram showing a structure in which the sound absorbing material 150 is placed closer to the sound source than the resonator 10 (the present invention); (B) is a diagram showing a structure in which the sound absorbing material 150 is placed closer to the sound receiving side than the resonator 10 (comparative example); ). FIG. 3 is a diagram showing the dimensions of an analysis target by a two-dimensional boundary element method. It is a figure which shows the acoustic energy which passes the virtual surface 2 calculated|required by analysis to the sound receiving side. FIG. 3 is a diagram showing the energy of noise absorbed by a sound absorbing material determined by analysis. FIG. 3 is a diagram showing acoustic energy passing through the virtual surface 1 to the sound receiving side, which is determined by analysis. It is a figure explaining opening structure 100 for ventilation concerning other embodiments of the present invention. It is a figure explaining opening structure 100 for ventilation concerning other embodiments of the present invention. It is a figure explaining opening structure 100 for ventilation concerning other embodiments of the present invention. It is a figure explaining opening structure 100 for ventilation concerning other embodiments of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. The ventilation opening structure 100 according to the present invention utilizes a resonator 10 having a closed cavity behind it as shown in FIG. 1, in which a resonance phenomenon occurs due to a slit structure. FIG. 1(A) is a perspective view of such a resonator 10. Moreover, FIG. 1(B) is a cross-sectional view taken perpendicularly to the longitudinal direction of the slit-shaped opening 50 of the resonator 10 of FIG. 1(A).

As shown in FIG. 1, the resonator 10 used in the ventilation opening structure 100 according to the present invention is basically composed of a quadrangular prism-shaped housing 40 with a hollow inner space. One surface of the casing 40 constituting the resonator 10 includes a longitudinal slit-shaped opening 50 and partition walls 60 arranged on both sides of the slit-shaped opening 50 and extending into the space inside the resonator 10. It is characterized by having the following. The two opposing partition walls 60 have similar dimensions. Here, each dimension of the resonator 10 in which the resonance phenomenon occurs is represented by the symbols shown in FIG. Note that one surface of the housing 40 where the slit-shaped opening 50 is formed and the main surface of the partition wall 60 are orthogonal to each other.

When each dimension of the resonator 10 is sufficiently small relative to the wavelength, the acoustic impedance ratio Z at the slit-shaped opening 50 can be determined by the following equation (1).

However, f represents the frequency of the noise, c represents the speed of sound, and ρ represents the density of the medium (air). Further, V _n is the volume of the space other than the shaded area in FIG. It is calculated using the following equation (2) in consideration of edge correction. Note that the second term in brackets [ ] in equation (2) is a term related to the aperture end correction. In addition, the hatched space in FIG. 1(B) corresponds to the air layer of the resonator 10 in which the resonance phenomenon occurs.

Further, V is the volume of the cavity of the resonator 10 (volume of the air layer), which is calculated by the following equation (3).

Further, S is the area of the slit-shaped opening 50 (slit opening), and is calculated by the following equation (4).

The first term on the right side of equation (1), r, is acoustic resistance such as friction that occurs between the surface of the partition wall 60 of the resonator 10 and air, where the resonance phenomenon occurs. When the partition wall 60 is made of a material with a smooth surface such as metal, the acoustic resistance r becomes an extremely small value, and the acoustic impedance ratio Z at the opening of the slit-shaped opening 50 becomes almost 0 at a resonance frequency f that satisfies the following equation. Become.

When two resonators 10, which function as resonators that produce such a resonance phenomenon, are arranged oppositely along the upper and lower inner walls 105 of the ventilation opening structure 100, as shown in FIG. The opposing slit portions are in an acoustically "soft" state, and the noise of frequency f propagating from the sound source side is reflected back to the sound source side and does not propagate to the sound receiving side.

FIG. 2 is a diagram illustrating a ventilation opening structure 100 according to an embodiment of the present invention. FIG. 2 is a sectional view of the ventilation opening structure 100 taken perpendicularly to the longitudinal direction of the ventilation opening structure 100 (or the longitudinal direction of the slit-shaped opening 50). The ventilation opening structure 100 has an inner wall 105, and a space surrounded by the inner wall 105 functions as a ventilation path.

In the ventilation opening structure 100 according to the present embodiment, there is a noise source on the sound source side (outdoor side outside the building), and the noise from the noise source is propagated to the sound receiving side (indoor side inside the building). This will be explained using as an example. In addition, although the explanation will be made assuming that the longitudinal direction (perpendicular to the plane of the paper) of the ventilation opening structure 100 itself is installed in the horizontal direction, the installation method of the ventilation opening structure 100 is limited to this example. I can't do it.

In this ventilation opening structure 100, of the four inner walls 105 forming the ventilation opening structure 100, two of the inner walls 105 that face each other vertically are set in an acoustically "soft" state. That is, as shown in FIG. 2, two resonators 10 are provided inside the ventilation opening structure 100 so as to face the upper and lower inner walls 105, so that the opposing wall surfaces are acoustically "soft", That is, the acoustic impedance ratio Z on the surface of the wall becomes 0, and the noise propagated from the sound source side is reflected back to the sound source side and is prevented from propagating to the sound receiving side.

Note that in this embodiment, the explanation is based on an example in which two opposing wall surfaces whose surfaces have an acoustic impedance ratio Z of 0 face each other in the vertical direction, but the acoustic impedance ratio Z of the surfaces is 0. The two opposing wall surfaces may be horizontally opposing.

According to the ventilation opening structure 100 as shown in FIG. 2, at the resonant frequency of the resonator 10, the acoustic impedance ratio in the slit-shaped openings 50 of the opposing resonators 10 becomes almost 0, and the The incident noise is reflected outdoors and does not propagate indoors (downstream).

On the other hand, although a noise reduction effect can be expected for the resonant frequency f based on the above equation (5), almost no effect can be obtained at frequencies far from the resonant frequency. Therefore, in order to reduce noise having components in a wide frequency range, the ventilation opening structure 100 according to the present invention uses a porous sound absorbing material 150 such as glass wool or polyester together with the two resonators 10. ing. In the present invention, the two resonators 10 are assigned to reduce noise in a low frequency range, while the sound absorbing material 150 is assigned to reduce noise in a high frequency range, so that a noise reduction effect is produced over a wider frequency range. I have to.

Furthermore, in the ventilation opening structure 100 according to the present invention, the two resonators 10 and the two sound absorbing materials 150 are arranged adjacent to each other. Further, in the ventilation opening structure 100 according to the present invention, the ventilation path is arranged so that the surface has no level difference. That is, the resonator 10 and the sound absorbing material 150 that are adjacent to each other are arranged flush with each other.

Further, in the ventilation opening structure 100 according to the present invention, the sound absorbing material 150 is arranged closer to the sound source than the resonator 10. Note that when a plurality of adjacent resonators and a sound absorbing material are arranged side by side, the sound absorbing material is arranged closer to the sound source than all the resonators.

Below, the results of verifying the effects of the present invention using the theoretical background and numerical analysis will be described regarding the arrangement of the sound absorbing material 150 closer to the sound source than the resonator 10.
[Theoretical background]
FIG. 3 shows a cross-sectional view of a part of the outer wall of a building and an example of a slit-shaped ventilation opening structure 100 provided therein, and FIG. 3(B) is a diagram showing a structure in which the sound absorbing material 150 is arranged closer to the sound receiving side than the resonator 10 (comparative example). FIG.

The resonators 10 are arranged facing each other for the purpose of reducing noise propagating from the outdoor side, that is, the sound source side, to the indoor side, that is, the sound receiving side, through this ventilation opening structure. Furthermore, the present invention proposes that the sound absorbing material 150 be placed closer to the sound source than the resonator 10.

Note that in FIG. 3, the sound absorbing materials 150 are arranged opposite to each other across the ventilation path similarly to the resonator 10, but they do not necessarily need to be arranged opposite to each other as illustrated. Even when the sound absorbing material 150 is placed only on one side, a certain degree of noise reduction effect can be expected.

Here, consider the energy of noise that enters the air passage from the sound source side, propagates to the sound receiving side, or is re-radiated to the sound source side. Note that the generally known effect of changing the energy of the noise propagating through the ventilation path depending on the frequency of the noise and the length of the ventilation path will not be particularly described below.

Let E _i be the energy of the noise that enters the air passage from the sound source side, and E _t be the energy of the noise that propagates to the sound receiving side via the air passage. Also, let E _r be the energy of the noise that enters from the ventilation path and re-radiates toward the sound source.

When no sound absorbing material is arranged, the relationship between the energy E _i of the noise incident on the ventilation path and the energy E _t of the noise propagating to the sound receiving side can be expressed by the following equation (7).
_Et =τ× _Ei ...(7)
In the above equation (7), τ indicates the rate at which noise propagates from the sound source side to the sound receiving side through the portion where the resonator 10 is arranged, that is, the noise transmission rate (0≦τ≦1). Near the resonance frequency of the resonator 10, τ becomes extremely small, and the energy of the noise propagating to the sound receiving side is significantly reduced. In addition, since the rate at which noise is reflected at the part where the slit resonator is placed and propagated to the sound source side again is (1-τ), the energy Er of the noise re-radiated from the sound source side of the air passage can be calculated using the following formula. As in (8).
E _r = (1-τ)×E _i ...(8)
As shown in FIG. 3A, when the sound absorbing material 150 is placed on the sound source side of the resonator 10, the energy absorbed by the sound absorbing material 150 when the noise propagates through the part where the sound absorbing material 150 is placed is α× It can be expressed as E _i . Here, α indicates the rate at which energy is absorbed by the sound absorbing material when noise propagates through the portion where the sound absorbing material 150 is arranged (0≦α≦1). In other words, the proportion of energy that propagates through the portion where the sound absorbing material 150 is arranged without being absorbed by the sound absorbing material 150 is (1-α).

In this case, the energy of the noise that passes through the portion where the sound absorbing material 150 and the resonator 10 are arranged and propagates to the sound receiving side is expressed by the following equation (9).
E _t = (1-α) τ×E _i ...(9)
Furthermore, the energy of the noise reflected at the part where the resonator 10 is placed and re-radiated from the sound source side is:
E _r = (1-α) ² (1-τ)×E _i ...(10)
It is.

Here, (1-α) ² is when the noise propagates from the sound source side of the air passage through the part where the sound absorbing material 150 is arranged toward the part where the resonator 10 is arranged, and after that when the resonator 10 is arranged. This indicates that energy is absorbed twice by the sound absorbing material 150 when the noise is reflected at the portion where the sound absorbing material 150 is placed and propagating toward the sound source side through the portion where the sound absorbing material 150 is arranged.

If the energy of noise absorbed by the sound absorbing material 150 is E _a , the following relational expression (11) holds true from the law of conservation of energy,
E _i =E _t +E _r +E _a ...(11)
By substituting equations (9) and (10), the following equation (12) is obtained.
E _a = {α+(1-α)(1-τ)α}E _i ...(12)
The first term in { } of the above equation (12) is the absorption by the sound absorbing material when noise propagates from the sound source side of the air passage toward the part where the resonator 10 is located. The second term is the energy absorbed by the sound absorbing material 150 when the noise is then reflected at the part where the resonator 10 is placed and propagates through the part where the sound absorbing material 150 is placed towards the sound source. means.

On the other hand, when the sound absorbing material 150 is placed on the sound receiving side of the resonator 10 as shown in FIG. The energy of the noise is
E _t = τ(1-α)×E _i ...(13)
It is. In addition, the noise energy reflected from the part where the resonator 10 is placed and re-radiated from the sound source side is
E _r =(1-τ)×E _i ...(14)
It is.

In this case, the noise energy E _a absorbed by the sound absorbing material 150 is expressed by the following equation (15) according to the law of conservation of energy.
E _a = τα × E _i (15)
From the above, a case where the sound absorbing material 150 is placed on the sound source side of the resonator 10 and a case where the sound absorbing material 150 is placed on the sound receiving side will be compared.

First, when comparing equations (9) and (13), the energy of the noise propagating through the air passage to the sound receiving side remains the same regardless of the placement position of the sound absorbing material 150. That is, even if the sound absorbing material 150 is arranged in a different position, the original performance of reducing noise propagation from the ventilation passage provided in the building is not impaired.

Next, subtracting the right side of equation (15) from the right side of equation (12) yields (2 - α) (1 - τ) α × E _i , and from the conditions of 0≦τ≦1 and 0≦α≦1. It becomes a positive value. This is because when the sound absorbing material 150 is placed on the sound source side of the resonator 10, the energy of the noise is absorbed by the sound absorbing material. In other words, when the sound absorbing material 150 is used together with the resonator 10, the noise energy is absorbed more effectively. Show what you can do.

Furthermore, when comparing equations (10) and (14), E _r in equation (10) is clearly smaller than E _r in equation (14). From this, it is clear that when the sound absorbing material 150 is placed on the sound source side of the resonator 10, the energy of the noise re-radiated from the air passage is smaller. This means that it is possible to reduce noise in the entire environment, including the building and its surroundings.

If there are other buildings of similar height or higher around the building in question, the noise re-radiated from the ventilation passages will be reflected on the exterior walls of the surrounding buildings and then enter the exterior walls and ventilation passages of the building again. . Reducing noise in the entire environment including the surrounding area is also effective from the perspective of reducing noise propagating from the outdoors into the interior of the building.
[Numerical analysis]
The two-dimensional boundary element method was used for the analysis.

As shown in FIG. 4, the analysis target was assumed to be a ventilation opening structure with a width of 100 mm provided in an infinite wall with a thickness of 300 mm. For two-dimensional analysis, we assume a structure in which the cross sections shown in the figure continue indefinitely in the depth direction.

FIG. 4(A) shows a calculation model when the sound absorbing material is placed on the sound source side of the resonator, and FIG. 4(B) shows a calculation model when the sound absorbing material is placed on the sound receiving side of the resonator. The dimensions of each part of the resonator are set so that the resonant frequency is around 630 Hz. It was also assumed that the sound absorbing material had a sound absorbing performance equivalent to that of glass wool with a density of 32 kg/m ³ and a thickness of 50 mm.

A plane sound wave is incident from the outdoor side, that is, the sound source side, and the acoustic energy that passes through the virtual surfaces 1 and 2 indicated by broken lines in FIG. 4 toward the indoor side, that is, the sound receiving side, was determined by analysis.

The analysis is performed on pure tones of every 1/27 octave, and the acoustic energy passing through the obtained virtual plane in the direction of the sound receiving side is averaged in 9 increments around the 1/3 octave band center frequency. The analysis results were in a 3-octave band.

FIG. 5 shows the acoustic energy passing through the virtual surface 2 to the sound receiving side, that is, the calculation result of E _t in the above. There is no difference in the calculation results when the sound absorbing material is placed on the sound source side and on the sound receiving side of the slit resonator, and as stated above, regardless of the placement position of the sound absorbing material, the ventilation path is It can be confirmed that the energy of the noise propagating to the side does not change.

FIG. 6 shows the result of subtracting the acoustic energy passing through the virtual surface 2 to the sound receiving side from the acoustic energy passing through the virtual surface 1 to the sound receiving side, that is, the calculation of the noise energy E _a absorbed by the sound absorbing material in the above. Show the results. In the band that includes the resonant frequency of the resonator and the surrounding band, when the sound absorbing material is placed on the sound source side of the resonator, the noise energy absorbed by the sound absorbing material is greater than when it is placed on the sound receiving side. As mentioned above, it can be confirmed that noise energy can be absorbed more effectively.

FIG. 7 shows the acoustic energy passing through the virtual surface 1 to the sound receiving side, that is, the calculation result of E _i −E _r in the above.

In the band including the resonant frequency of the resonator and the surrounding band, when the sound absorbing material is placed on the sound source side of the resonator, the sound passing through the virtual surface 1 to the sound receiving side is lower than when the sound absorbing material is placed on the sound receiving side. It has a lot of energy. Here, in the two analyses, since the conditions such as the position of the sound source are the same, the energy E _i that enters the air passage is the same. In other words, from these analysis results, it can be confirmed that when the sound absorbing material is placed on the sound source side of the slit resonator, the energy E _r re-radiated from the sound source side of the air passage is smaller than when it is placed on the sound receiving side. .

In the ventilation opening structure 100 according to the present invention, the sound absorbing material 150 is disposed flush with the resonator 10 and closer to the sound source than the resonator 10. For example, compared to the case where the sound absorbing material 150 is arranged on the sound receiving side of the resonator 10, the noise re-radiated from the ventilation opening structure 100 can be reduced, and the noise of the entire environment including the surroundings can be reduced. becomes possible.

Next, other embodiments of the present invention will be described. FIG. 8 is a diagram illustrating a ventilation opening structure 100 according to another embodiment of the present invention. FIG. 8 is a cross-sectional view of another embodiment of the ventilation opening structure 100 taken perpendicularly to the longitudinal direction of the ventilation opening structure 100 (or the longitudinal direction of the slit-shaped opening 50).

In another embodiment of the ventilation opening structure 100, a partition plate member 35 is further provided in the resonator 10 described above, and the space inside the resonator 10 is divided into two. Such a partition plate member 35 also functions as a partition wall part 60. By providing the partition plate member 35 as shown in FIG. 8, two slit resonators having a space A and a space B can be configured in one resonator. Note that "spaces" such as space A and space B are underbard in the drawings.

In the resonators based on each space, the acoustic impedance ratio Z of the slit portion 50 is approximately 0 at the respective resonance frequencies f ₁ and f ₂ , and as shown in FIG. By arranging them, the noise reduction effect can be achieved for multiple frequencies. In this embodiment, the sound absorbing material 150 is further arranged flush with the resonator 10 and closer to the sound source than the resonator 10.

In the noise reduction structure 1 according to such another embodiment, by appropriately changing the position of the partition plate member 35, it is possible to configure resonators 10 having various resonance frequencies even when using the resonator 1 of the same size. be. Further, according to this embodiment as well, it is possible to reduce the noise re-radiated from the ventilation opening structure 100, and it is possible to enjoy the effect that it is possible to reduce the noise in the entire environment including the surrounding area. .

Next, other embodiments of the present invention will be described. FIG. 9 is a diagram illustrating a ventilation opening structure 100 according to another embodiment of the present invention. FIG. 9 is a sectional view taken vertically in the longitudinal direction of the ventilation opening structure 100 (or in the longitudinal direction of the slit-shaped opening 50).

In the ventilation opening structure 100 according to another embodiment of FIG. 9, the resonator 10 has two resonators, each consisting of a space A and a space C, separated by two partition plate members 35 separated by a distance a _t . The structure is as follows. In this case, the slit between the two resonators becomes a slit-like opening 50 without an air layer behind it. In this case, the partition plate member 35 also functions as a partition wall part 60.

When such resonators 10 are disposed facing each other along the inner wall of the ventilation opening structure 100, for frequencies where the cross-sectional dimension of the ventilation opening structure 100 and the interval a _t of the partition plate members 35 are half a wavelength or less, The slit-shaped opening 50 having no air layer behind it functions as an acoustic tube (space B).

At this time, the dimension D of the outer shell member 20 corresponds to the pipe length of the acoustic tube, and at the frequency f _t where 1/4 of the wavelength is equal to D and the odd multiples thereof, the acoustic wave of the slit-shaped opening 50 of the acoustic tube is The impedance ratio Z becomes 0 and exhibits a noise reduction effect.

In general, f _t as described above is higher than the resonance frequency f ₁ or f ₂ of the slit resonators (space A and space C), so the structure of the combination of the slit resonator and acoustic tube as shown in Fig. 9 is The noise reduction structure 1 using the resonator 10 can exhibit a noise reduction effect over a wide range of frequencies. In forming the space A and the space C, the lengths l _a and l _c of the partition wall portions 60 in the slit resonators (space A and space C) are made different.

Furthermore, in this embodiment, the sound absorbing material 150 is arranged flush with the resonator 10 and closer to the sound source than the resonator 10 .

The noise reduction structure 1 according to such another embodiment is configured to include a resonator 10 including an acoustic tube (space B) and a sound absorbing material 150, and is capable of reducing noise in a wide range of frequencies. , it is possible to reduce the noise re-radiated from the ventilation opening structure 100, and it is possible to enjoy the effect that it is possible to reduce the noise in the entire environment including the surrounding area.

Next, other embodiments of the present invention will be described. In the embodiments described so far, the resonators 1 of the same size are arranged so that their slit portions 50 face each other. In contrast, in this embodiment, the resonator 1 is provided only on one side of the ventilation path in the ventilation opening structure 100. FIG. 10 is a diagram showing such a ventilation opening structure 100. FIG. 10(A) shows a case where the resonators 10 are arranged in "one side arrangement", and FIG. 10(B) shows a case where the resonators 10 are arranged in "one side parallel arrangement". ” are shown in each case. The sound absorbing material 150 is flush with the resonators 10 and is arranged closer to the sound source than any of the resonators 10 .

Numerical analysis has confirmed that sufficient noise reduction effects can be expected from such arrangement methods such as ``one-sided placement'' and ``one-sided parallel placement.'' If only "one side arrangement" or "one side parallel arrangement" can be adopted due to layout or other reasons, such an arrangement can be adopted as appropriate.

Furthermore, in this embodiment as well, the sound absorbing material 150 is disposed closer to the sound source than any of the resonators 10, and can reduce the noise re-radiated from the ventilation opening structure 100, and can reduce the noise that is re-radiated from the ventilation opening structure 100. It is possible to enjoy the effect that the overall noise can be reduced.

Next, other embodiments of the present invention will be described. FIG. 11 is a diagram illustrating a resonator 10 used in a noise reduction structure 1 according to another embodiment of the present invention. FIG. 11(A) shows the resonator 10 used in the ventilation opening structure 100 according to the embodiments described so far, and FIG. 11(B) shows the resonator 10 used in the noise reduction structure 1 according to the present embodiment. It shows. The ventilation opening structure 100 according to this embodiment is characterized in that the resonator 10 shown in FIG. 11(B) is arranged in the ventilation opening structure 100. The other configurations are the same as those of the embodiments described so far, and therefore their description will be omitted.

As shown in FIG. 11(A), the resonator 10 of the ventilation opening structure 100 according to the embodiments described so far is provided with partition parts 60 disposed on both sides of the slit part 50, and these partition parts 60 had a length l in the depth direction.

On the other hand, the resonator 10 of the ventilation opening structure 100 of this embodiment shown in FIG. 11(B) has a structure in which the partition wall portions 60 on both sides of the slit portion 50 are omitted. The partition wall portion 60 is omitted, but instead, the front surface of the resonator 10, which includes at least the slit portion 50, has a thickness of l.

Due to the plate thickness l, the V _n described in the first embodiment occurs also in the resonator 10 used in this embodiment. As a result, even with the ventilation opening structure 100 according to this embodiment in which the resonator 10 in which the partition wall portion 60 is omitted is used, it is possible to enjoy the same effects as the ventilation opening structure 100 described so far. .

As described above, in the ventilation opening structure according to the present invention, the sound absorbing material is flush with the resonator and is placed closer to the sound source than the resonator. Compared to the case where the material is placed on the sound receiving side from the resonator, the noise re-radiated from the ventilation opening structure can be reduced, and the noise in the entire environment including the surrounding area can be reduced.

Further, according to the ventilation opening structure according to the present invention, by arranging the sound absorbing material and the resonator adjacent to each other, it is possible to downsize the noise reduction device. It is also possible to configure a noise reduction section by integrating a space for arranging a sound absorbing material and a resonator.

Further, according to the ventilation opening structure according to the present invention, the downsized and integrated ventilation opening structure can keep manufacturing costs low, and can be easily installed in the ventilation path, thereby keeping construction costs low. be able to.

In addition, according to the ventilation opening structure according to the present invention, by arranging the sound absorbing material and the resonator so that the surface forms a ventilation path without any level difference, a smooth flow of air is realized, and turbulence due to the level difference is realized. This can prevent the ventilation performance from deteriorating due to this.

According to the ventilation opening structure according to the present invention, by arranging the sound absorbing material closer to the sound source than the resonator, noise energy can be more effectively absorbed by the sound absorbing material.

In addition, according to the ventilation opening structure according to the present invention, the noise reflected at the part where the resonator is arranged and re-radiated to the outdoors from the ventilation opening is reduced, and the noise is reduced in the entire environment including the building and its surroundings. can do.

Each of the above effects can be achieved without impairing the original performance of reducing noise propagation from ventilation openings provided in buildings.

10... Resonator 35... Partition plate member 40... Housing 50... Slit-shaped opening 60... Partition wall part 100... Ventilation opening structure 105... Inner wall 110... Interior wall 120...Exterior wall 150...Sound absorbing material

Claims (4)

a resonator provided in an inner wall of an opening in a building and having a slit-like opening;
A ventilation opening structure including a sound absorbing material provided adjacent to the resonator,
The space surrounded by the inner wall functions as a ventilation path,
The slit-shaped opening is arranged on one surface of a housing constituting the resonator,
The sound-absorbing material is arranged closer to the sound source than the resonator so that the one surface of the resonator and the surface of the sound-absorbing material are flush with each other and form a ventilation path without a step ,
A ventilating opening structure characterized in that the sound absorbing material exhibits a sound absorbing effect at frequencies apart from the resonant frequency of the resonator . The ventilation opening structure according to claim 1, wherein the resonators are arranged in pairs so that the slit-like openings face each other. The ventilation opening structure according to claim 1 or 2, comprising a plurality of adjacent resonators, and wherein the sound absorbing material is arranged closer to the sound source than all the resonators. The ventilation opening structure according to any one of claims 1 to 3, wherein the resonator has an air layer.

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