JP3071637B2 - Resonator type sound absorber and sound absorbing ceiling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonator-type sound absorber utilizing the principle of a Helmholtz resonator and a sound-absorbing ceiling in which the resonator-type sound absorber is suspended from a ceiling surface.

[0002]

2. Description of the Related Art Conventionally, as a resonator type sound absorber, FIG.
As shown in FIG. 1, there is a type in which a flat plate 21 (thickness 1) having a plurality of holes 21a (diameter d) is arranged at an interval L in parallel with the wall surface W. This resonator type sound absorber has a flat plate 21 and a wall surface W.
Assuming a plurality of virtual spaces defined by dotted lines so as to correspond to the holes 21a, a space between the space and the holes 21a of the flat plate 12 constitutes a plurality of Helmholtz resonators. Conceivable. The Helmholtz resonance frequency fr of this Helmholtz resonator is given by: fr = c / (2π) · (where l is the length of the hole 21a, s is the cross-sectional area of the hole, and V is the volume of the virtual space per hole 21a. s / (V (l + δ)) ^1/2
(δ: pipe end correction value). When the shape of the hole 21a of the flat plate 21 is a circle, the pipe end correction value δ = 0.8d. Thus, the resonator-type sound absorber has a high sound absorption coefficient in a sound range of the Helmholtz resonance frequency fr due to the plurality of Helmholtz resonators.

As another resonator-type sound absorber, as shown in FIG. 19, each of the holes 22a is provided on one flat surface side of a flat plate 22 (thickness 1) having a plurality of holes 22a (diameter d). According to Japanese Patent Application Laid-Open No. 54-77414, there is provided a configuration in which a plurality of substantially triangular prism-shaped spaces are formed by providing the partition plates 23 each having a substantially isosceles triangular cross section. This resonator type sound absorber has a flat plate 22 with a distance 2L from the apex of two equal sides of an isosceles triangle of the cross section of the space to the flat plate 21.
Since the volume of the substantially triangular prism-shaped space facing the plane on the partition plate 23 side is the same as the volume V of the space of the Helmholtz resonator of the resonator type sound absorber of FIG. 18, the resonator type sound absorption of FIG. It has the same Helmholtz resonance frequency fr as the body. The resonator type sound absorber shown in FIG.
The sound absorption characteristics are improved as compared with a resonator type sound absorber having no partition between the first and wall surfaces W.

[0004]

The resonator-type sound absorber shown in FIGS. 18 and 19 has a high sound absorption coefficient in a narrow sound range near the Helmholtz resonance frequency fr, but has a sound absorption frequency other than that. Has the disadvantage that sound absorption is not sufficient.

Further, the resonator type sound absorber shown in FIGS. 18 and 19 has a high sound absorption coefficient with respect to a sound in a middle to high frequency range of 500 Hz or more, and has a high sound absorption coefficient with respect to a sound in a low frequency range less than 500 Hz. By combining with a porous sound absorber having an insufficient sound absorption coefficient, it is possible to obtain sound absorption characteristics capable of coping with sounds in a wide range. However, since the resonator-type sound absorber shown in FIGS. 18 and 19 has high sound absorption performance only in a narrow sound range near the Helmholtz resonance frequency fr, the opening efficiency of the perforated plate of the cylinder and the inner surface of the cylinder are not suitable. Since it is necessary to combine a plurality of types of resonator-type sound absorbers corresponding to a plurality of resonance frequencies by changing the volume of the space to be used, there is a disadvantage that the manufacturing cost is high.

SUMMARY OF THE INVENTION An object of the present invention is to provide a resonator-type sound absorber having a sound absorbing ability in a frequency range other than the Helmholtz resonance frequency and capable of increasing the sound absorption coefficient in a wide range including the two frequency ranges. Is to provide.

Another object of the present invention is to provide a sound absorbing performance corresponding to a wide range from a low range to a high range by combining a small number of types of resonator type sound absorbers and a porous type sound absorber. To provide a sound-absorbing ceiling.

[0008]

According to a first aspect of the present invention, there is provided a resonator-type sound absorber having a substantially rectangular cross section formed of a perforated plate having a predetermined aperture ratio. On the inner periphery of the first partition plate made of a sound insulating material provided parallel to the axis of the cylinder along the diagonal line of the cylinder, and on the inner periphery of the cylinder, the other of the other of the cylinder A second partition plate made of a sound insulating material provided along a diagonal line parallel to the axis of the cylindrical body and intersecting with the first partition plate, and a sound insulating material for closing openings at both ends of the cylindrical body. It is characterized by having a closed lid.

Further, the resonator-type sound absorber according to claim 2 is provided in the resonator-type sound absorber according to claim 1 in four spaces partitioned by the first and second partition plates in the cylinder. And an adjusting partition plate made of a sound insulating material that forms a space facing the inner surface of the cylindrical body with a smaller volume than the space.

Furthermore, the resonator-type sound absorber according to claim 3, in the resonator-type sound absorber according to claim 1 or 2, the length of one side of the substantially rectangular cross-section of the tubular body and l ₀ The resonance frequency based on the volume of the four spaces partitioned by the first and second partition plates in the cylinder, the aperture ratio of the perforated plate of the cylinder, and the length of the holes of the perforated plate, It is characterized in that the frequency is not more than 500 Hz and does not coincide with the frequency c / (4l ₀ ) (where c is the sound speed).

According to a fourth aspect of the present invention, there is provided the resonator type sound absorbing body according to the third aspect, wherein the axial length of the cylindrical body is l1, and the _first length of the first cylindrical body in the cylindrical body is l1. The resonance frequency based on the volume of the four spaces partitioned by the second partition plate, the aperture ratio of the perforated plate of the cylindrical body, and the length of the hole of the perforated plate is set to a frequency c / (4l ₁ ) (where , C are sound speeds).

According to a fifth aspect of the present invention, there is provided a resonator type sound absorber, wherein the resonator type sound absorber according to any one of the first to fourth aspects and the porous sound absorber are suspended from a ceiling surface. .

[0013]

According to the resonator type sound absorber of the first aspect, four Helmholtz resonators are formed by the four spaces partitioned by the first and second partition plates in the cylinder, and the space is formed by the four Helmholtz resonators. Based on the volume of the perforated plate, the aperture ratio of the perforated plate, the length of the hole of the perforated plate, and the like, the sound absorption coefficient in a narrow sound range near one Helmholtz resonance frequency is increased. Further, the sound absorption coefficient is increased even in a sound range of a frequency based on the length of two sides of the substantially rectangular section of the cylindrical body and the axial length of the cylindrical body.

Therefore, the sound range of at least one of the frequencies based on the length of the two sides of the substantially rectangular cross section of the cylindrical body and the axial length of the cylindrical body and the sound range of the Helmholtz resonance frequency do not match. Accordingly, it is possible to increase the sound absorption coefficient in the sound range of different frequencies, and to obtain sound absorption characteristics in a wide range.

According to the resonator type sound absorber of the second aspect, in the resonator type sound absorber of the first aspect, the volume of the four spaces facing the inner surface of the cylindrical body is reduced by the adjusting partition plate. By adjusting each of them, the Helmholtz resonance frequency can be arbitrarily adjusted. Further, by adjusting the volumes of the four spaces so as to be different from each other, it is possible to realize a resonator type sound absorber having sound absorption characteristics corresponding to up to four kinds of Helmholtz resonance frequencies.

According to the resonator type sound absorber of the third aspect, in the resonator type sound absorber of the first or second aspect, the length of one side of the substantially rectangular cross section of the cylindrical body is l _0. And 4 divided by the first and second partition plates in the cylindrical body.
The Helmholtz resonance frequency based on the volume of one space, the aperture ratio of the perforated plate of the cylinder, and the length of the hole of the perforated plate is set to 500H.
z or less and the Helmholtz resonance frequency is frequency c /
(4l ₀ ) (where c is the sound speed).
Therefore, it is possible to increase the sound absorption coefficient in the sound range of a frequency different from the Helmholtz resonance frequency and the frequency based on the length l ₀ of one side of the substantially rectangular cross section of the cylinder, and to widen the range in which the sound absorption coefficient is high in the low sound range. .

Further, according to the resonator-type sound absorber of the fourth aspect resonator type sound absorber according to claim 3, the axial length of the cylindrical body and l _1, of the tubular body above the 1. The Helmholtz resonance frequency based on the volume of the four spaces partitioned by the second partition plate, the aperture ratio of the perforated plate of the cylindrical body, and the length of the hole of the perforated plate does not match the frequency c / (4l ₁ ). (However, c is the speed of sound). Therefore, it is possible to increase the sound absorption coefficient in a sound range having a frequency different from the Helmholtz resonance frequency and the frequency based on the axial length l ₁ of the cylinder, and to widen the range in which the sound absorption ratio is high in the low sound range.

According to the sound absorbing ceiling of the fifth aspect,
The sound absorbing coefficient in the low range is increased by the resonator type sound absorbing body according to any one of claims 1 to 4, and the sound absorbing rate in the middle and high range is increased by the porous sound absorbing body. The resonator type sound absorber has a sound absorption characteristic of a frequency range different from the Helmholtz resonance frequency, a frequency based on the length of two sides of a substantially rectangular cross section of the cylinder, and the length of the cylinder in the axial direction. With the above-described resonator type sound absorber, sound absorption characteristics having a high sound absorption coefficient with respect to a low sound range can be obtained. Therefore, by combining a small number of resonator-type sound absorbers and porous sound absorbers, it is possible to realize a sound-absorbing ceiling with a high sound absorption coefficient over a wide range of sounds.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a resonator type sound absorber according to the present invention.

FIG. 1 is a perspective view of a resonator-type sound absorber according to an embodiment of the present invention, and FIG. 2 is a front view of a perforated plate 10. 3 shows a side view of the resonator-type sound absorber, FIG. 4 shows a sectional view taken along line IV-IV in FIG. 2, and FIG. 5 shows a sectional view taken along line VV in FIG. Is shown.

In FIG. 1, reference numeral 1 denotes a cubic cylinder having a substantially square cross section and a side length l ₀ of 450 mm, and 2 denotes the cylinder 1
The first partition plate 3 made of a calcium silicate plate as an example of a sound insulating material provided on the inner periphery of the cylinder 1 along the diagonal line of the cylinder 1 and in parallel with the axis of the cylinder 1, A second partition plate made of a calcium silicate plate as an example of a sound insulating material provided so as to be parallel to the axis of the cylindrical body 1 and intersect with the first partition plate 2 along the other diagonal line of the cylindrical body 1. . The cylindrical body 1 has a substantially rectangular L-shaped frame 6 (shown in FIG. 2) and a substantially square-shaped frame 6 with the long sides adjacent to each other of four substantially rectangular perforated plates 10 formed of a calcium silicate plate. It is fixed by a frame 7 (shown in FIG. 3) and forms a tube having a substantially square cross section. The perforated plate 10 has a plurality of holes 10a arranged in a lattice so as to have a predetermined aperture ratio. Although not shown in the opening portion of the cylindrical body 1 in FIG. 1, as shown in FIGS. 3 and 5, the opening portions at both ends of the cylindrical body 1 are sealed with a substantially square sealing lid 4. . Further, hanging hooks 5 (shown in FIGS. 2, 3, and 4) are fixed to the closed lids 4 in parallel with each other and near the corners of the closed lids 4, respectively. Further, the first partition plate 2 and the second partition plate 3 are divided into two portions at intersections in advance, and the divided four partition plates are combined and fixed in the cylindrical body 1.

In the resonator-type sound absorber having the above-described structure, the first partition plate 2, the second partition plate 3, and the sealing lid 4 surround the back of the four perforated plates 10, that is, the inner periphery of the cylindrical body 1. Formed in a substantially triangular prism shape, and based on the volume of this space, the aperture ratio of the perforated plate 10, the length of the hole 10a of the perforated plate 10, etc., a high sound absorption coefficient in a sound range of a specific resonance frequency. And a Helmholtz resonator having the following. The air in the hole 10a of the perforated plate 10 vibrates at the Helmholtz resonance frequency fr, consumes sound energy as frictional heat at that time, and has a sharp sound absorption characteristic in an extremely narrow frequency range around the Helmholtz resonance frequency fr. It has.

However, the above-mentioned resonator type sound absorber is used in a reverberation room.
(Not shown), the resonator-type sound absorber was measured for sound absorption using the reverberation chamber method sound absorption coefficient measurement method (JIS A 1409), and as shown in FIG. The sound absorption characteristics shown were obtained. In addition, the circles indicate the sound absorption characteristics when the flat plate 21 is arranged parallel to the wall surface W shown in FIG. 18 for comparison, and the squares indicate a substantially triangular prism-shaped space behind the flat plate 21 shown in FIG. This is the sound absorption characteristic of the case.

That is, the Helmholtz resonance frequency fr of the resonator type sound absorber is about 250 Hz determined by the volume of the space, the aperture ratio of the perforated plate 10, and the length of the hole 10a of the perforated plate 10. However, the sound absorbing characteristics of the resonator type sound absorbing body are such that the sound absorbing characteristic is such that the sound absorbing area has a frequency f ₀ lower than the Helmholtz resonance frequency, that is, a frequency range having a wavelength which is about four times the length l ₀ of one side of the substantially square cross section of the cylindrical body 1. Experiments have shown that the rate is higher. It should be noted that the frequency f ₀ is maintained even when the aperture ratio of the cylindrical body 1 of the resonator type sound absorber is changed in the range of 0.8 to 3% or the axial length l ₁ of the cylindrical body ₁ is changed. There was no change. Further, the cylinder 1
Of square cross-section of one side length of l ₀ 300 mm, the axial direction of the cylinder 1 a length l ₁ as 600 mm, were subjected to the same measurements as those described above, the frequency c / (4l ₀₎ and frequency c
Sound absorption characteristics indicating an improvement in the sound absorption coefficient in two different frequency ranges of / (4l ₁ ) (where c is the sound speed) were obtained.

In the above embodiment, the cylindrical body 1 is provided with the perforated plate 1.
0, but the same measurement as described above was performed using the perforated plate 10 as a porous plate, but the frequency c / (4l ₀ )
And a frequency c / (4l ₁ ) (where c is the sound velocity), and a sound absorption characteristic indicating an improvement in the sound absorption coefficient in a range of two different frequencies was obtained.

[0026] From the above, the length l ₀ and the cylindrical body axial length l ₁ of the first side of the substantially square cross-section of the tubular body 1, the resonator differs from the sound absorption characteristic is the Helmholtz resonator It was confirmed that it had a type sound absorber.

As described above, four Helmholtz resonators are formed by the four spaces surrounded by the perforated plate 10, the first and second partition plates 2, 3 and the sealing lid 4 in the cylindrical body 1. Volume of space, aperture ratio of perforated plate 10 and hole 10 of perforated plate 10
Based on the length of a, etc., the sound absorption coefficient in a narrow sound range near the Helmholtz resonance frequency fr is increased, and the sound absorption of the frequency f ₀ based on the length l ₀ of one side of the substantially square of the cylinder 1 is also performed. Increase the rate. Therefore, the length l ₀ of one side of the substantially square cross section of the cylindrical body 1 is changed so that the Helmholtz resonance frequency fr and the frequency f ₀ do not coincide with each other, so that the sound absorption coefficient of two different frequency ranges can be increased. . In addition, since it has a high sound absorption coefficient even in a sound range of a frequency based on the axial length l ₁ of the cylindrical body 1, by changing the length l ₁ ,
Helmholtz resonance frequency fr and axial length l _{1 of} cylinder ₁
, The sound absorption coefficient of the sound range of a different frequency can be increased.

Therefore, it is possible to realize a resonator type sound absorber having a wide range of sound absorption characteristics in a low sound range.

As shown in FIG. 8, a sound absorbing material 11 made of glass wool is attached to the inner peripheral side of the perforated plate 10 of the cylindrical body 1, or as shown in FIG. May be filled with a sound absorbing material 12 made of glass wool. In this case, the sound absorbing materials 11 and 12 provided behind the perforated plate 10 increase the flow resistance at the hole 10a of the perforated plate 10, so that the sound absorption coefficient can be further increased.

As shown in FIG. 10, four adjustment partitions are provided so that the cross section of each space partitioned by the first and second partition plates 2 and 3 on the inner periphery of the cylindrical body 1 becomes substantially trapezoidal. The volume of the space facing the inner surface of the perforated plate 10 of the cylindrical body 1 may be reduced by attaching the plate 13. Also, as shown in FIG. 11, one acute angle of the apexes of each of the substantially triangular cross-section spaces partitioned by the first and second partition plates 2 and 3 on the inner periphery of the cylindrical body 1 faces the apex. The adjustment partition plate 14 may be attached along a straight line extending to the side parallel to the axis of the cylinder 1 to reduce the volume of the space facing the inner surface of the perforated plate 10 of the cylinder 1. further,
As shown in FIG. 12, an adjusting partition plate 15 having a substantially V-shaped cross section is attached to each space partitioned by the first and second partition plates 2 and 3 on the inner periphery of the cylindrical body 1. 1 perforated plate 10
The volume of the space facing the inner surface may be reduced. Thus, the Helmholtz resonance frequency fr can be adjusted by adjusting the volume of the space facing the inner surface of the cylindrical body 1. In addition, the volumes of the four spaces in the cylindrical body 1 can be adjusted to different volumes, respectively.
A resonator type sound absorber having up to four Helmholtz resonance frequencies can be realized.

FIGS. 13 and 14 show an example of a porous sound absorbing body. The porous sound absorbing body includes a cylindrical body 11 made of rock wool 20 as a porous material having a substantially square cross section.
A sealing lid 14 made of a calcium silicate plate for sealing the opening of the cylinder 11 and a cylinder 11
First partition plate 1 made of a calcium silicate plate fixed to partition the inner periphery parallel to the axis of cylindrical body 11 along the diagonal line of
2 and a silicic acid fixed on the inner periphery of the cylindrical body 11 so as to partition the inner periphery perpendicular to the first partition plate 12 and in parallel with the axis of the cylindrical body 11 along the other diagonal line of the cylindrical body 11. A second partition plate 13 made of a calcium plate is provided, and hanging hooks 15 are fixed to the respective closed lids 14 in parallel with the plane and near the corners. At least one of the porous sound absorbers is suspended from a ceiling surface (not shown) using hanging hooks 15, 15, and as shown in FIG. By suspending the sound absorber using 5, 5, the porous sound absorber increases the sound absorption coefficient in the middle and high sound ranges, and the resonator type sound absorber increases the sound absorption coefficient in the low sound range. The resonator type sound absorber has a Helmholtz resonance frequency and a sound absorption characteristic of a sound range of a frequency different from a frequency based on a length of one side of a substantially square cross section of the cylinder 1 and an axial length of the cylinder 1, A wide variety of sound absorption characteristics can be obtained in a low sound range with a small number of resonator-type sound absorbers. Therefore, by combining the above-described porous sound absorber and a small number of resonator-type sound absorbers, it is possible to realize a sound-absorbing ceiling having a high sound absorption coefficient over a wide range from a low sound range to a high sound range.

The above-mentioned resonator type sound absorber and the porous sound absorber may be suspended independently from the ceiling surface.

Further, a plurality of resonator-type sound absorbers or a plurality of porous sound absorbers having the same cross section of the cylinder are connected in the axial direction of the cylinder to form one resonator having a different axial length. A sound absorber or a porous sound absorber may be formed and suspended from the ceiling surface. For example, as shown in FIG. 15, two resonator type sound absorbers 20 are connected in the axial direction and suspended from the ceiling surface.

Further, a plurality of resonator-type sound absorbers or a plurality of porous sound absorbers having the same axial length as one side of the substantially square cross section of the cylindrical body are formed by connecting each cylindrical body so that its axis is parallel and perpendicular to the axis. It is also possible to form a resonator-type sound absorber or a porous sound absorber having different lengths of sides in a direction perpendicular to the axis, and to suspend from the ceiling surface. For example, as shown in FIG. 16, two resonator-type sound absorbers 30 are connected to each other in a direction parallel to each axis and perpendicular to the axis, and suspended from a ceiling surface.

As described above, when a plurality of types of resonator-type sound absorbers or porous sound absorbers are arranged side by side and connected to each other, various types of resonator-type sound absorbers or porous sound absorbers having different side lengths can be formed. Sound absorbers having sound absorbing characteristics of various frequencies can be obtained based on the lengths of different sides.

Also, the resonator type sound absorber and the porous sound absorber are
Connected in the axial direction of the cylinder, or connected side by side at right angles to the axis of the cylinder, or connected side by side at right angles to the axis and axis of the cylinder, and connected in any combination Different shapes of sound absorbers may be formed and suspended from the ceiling surface. For example, as shown in FIG. 17, the resonator-type sound absorber 40 and the porous sound absorber having the same cross section of the cylindrical body may be connected in the axial direction and suspended from the ceiling surface.

The porous sound absorbing body is not limited to the cylindrical body having the rectangular cross section of the above embodiment, but may be any cylindrical, plate, spherical, etc. as long as it can be suspended from the ceiling surface.

In the porous sound absorber shown in FIG. 13 of the above embodiment, the length of the side of the cross section square of the cylindrical body 11 is l _2.
The length in the axial direction of the cylindrical body 11 is l _3, and the frequency c / (4l ₂ ) and the frequency c / based on the respective lengths l ₂ and l _3.
(4l ₃ ) (where c is the sound speed) may be set to 500 Hz or less. In this case, a porous sound absorber having an insufficient sound absorption coefficient with respect to a sound having a low frequency range of 500 Hz or less can have sound absorption characteristics that can cope with the low frequency range.

In the above embodiment, the first partition plate 2 and the second partition plate 3 are each divided into two portions at the intersections, and the four partition plates are fixed in the cylindrical body 1. Board or second
Alternatively, only one of the partition plates may be divided into two portions at intersections and fixed in the cylinder.

In the above embodiment, glass wool was used for the sound absorbing members 11 and 12 provided in the cylindrical body 1 shown in FIGS. 8 and 9. However, the present invention is not limited to this. , Felt and thick cloth may be used.

In the above embodiment, rock wool was used as the porous material of the porous sound absorber. However, the present invention is not limited to this, and glass wool, wood wool cement board, wood chip cement board, felt, plastic Foam (polyurethane foam or urea foam), soft fiberboard, thick cloth, ceramic material made by sintering inorganic material to make it permeable, aluminum made by sintering inorganic material to make it permeable A sponge or the like may be used.

In the above embodiment, the calcium silicate plate was used as the sound insulating material. However, the sound insulating material is not limited to this. Plywood, plaster board (gypsum board), acrylic plate, plastic plate, polycarbonate plate, vinyl chloride Plates, metal plates (such as aluminum plates, steel plates and iron plates), glass plates, hard boards, insulation boards, particle boards and gypsum cement plates may be used.

In the above embodiment, the perforated plate 1
Although a calcium silicate plate was used for 0, it is a matter of course that the cylindrical perforated plate may be one in which the sound absorbing material or the sound insulating material listed above has holes formed in the material satisfying the strength.

In the above embodiment, the cross-sectional shape of the cylindrical body 1 is substantially square, but the cylindrical body may be substantially rectangular in cross section. In this case, separately from the Helmholtz resonance frequency sound range, a sound absorption characteristic is obtained which shows improvement in the three frequency ranges based on the two sides of the cylinder having a substantially rectangular cross section having different lengths and the length of the cylinder in the axial direction. .

[0045]

As is apparent from the above description, the resonator type sound absorber according to the first aspect of the present invention is formed by a perforated plate and is divided into first and second partition plates in a cylindrical body having a substantially rectangular cross section. The four spaces form four Helmholtz resonators, and based on the volume of the space, the aperture ratio of the perforated plate, the length of the holes in the perforated plate, etc., a narrow sound range near one Helmholtz resonance frequency. And also increases the sound absorption coefficient for a sound range having a frequency based on the length of two sides of a substantially rectangular cross section of the cylindrical body and the axial length of the cylindrical body.

Therefore, according to the resonator type sound absorber of the first aspect of the present invention, at least one of the frequencies based on the length of two sides of the substantially rectangular cross section of the cylindrical body and the axial length of the cylindrical body. By making the sound range of one frequency and the Helmholtz resonance frequency not coincide with each other, it is possible to increase the sound absorption coefficient of different frequencies and obtain sound absorption characteristics in a wide range of sound range.

Further, the resonator-type sound absorber according to the second aspect of the present invention is the resonator-type sound absorber according to the first aspect, wherein the four spaces partitioned by the first and second partition plates in the cylinder are: Since the adjustment partition plates made of sound insulation material are provided to form a space facing the inner surface of the cylinder with a smaller volume than that space, the volume of each space facing the inner surface of the cylinder is adjusted respectively, and Helmholtz is adjusted. The resonance frequency can be set arbitrarily, and a resonator type sound absorber having sound absorption characteristics corresponding to up to four kinds of Helmholtz resonance frequencies can be realized.

[0048] Also, the resonator-type sound absorber of the invention of claim 3, in the resonator-type sound absorber according to claim 1 or 2, the length of one side of the substantially rectangular cross-section of the tubular body and l ₀ The resonance frequency based on the volumes of the four spaces partitioned by the first and second partition plates in the cylinder, the aperture ratio of the perforated plate of the cylinder, and the length of the holes in the perforated plate is 500 Hz or less, and Since the frequency c / (4l ₀ ) (where c is the sound speed) does not match, the sound absorption coefficient of the frequency range f = c / (4l ₀ ) different from the resonance frequency is increased, and the low frequency range of 500 Hz or less is set. Can increase the sound absorption coefficient in a wide range.

According to a fourth aspect of the present invention, there is provided a resonator-type sound absorber according to the third aspect, wherein the axial length of the cylindrical body is l1, and the _first and the second in the cylindrical body. The resonance frequency based on the volume of the four spaces partitioned by the two partition plates, the opening ratio of the perforated plate of the cylindrical body, and the length of the holes of the perforated plate is represented by a frequency c.
/ (4l ₁ ) (where c is the speed of sound), so that the sound absorption coefficient in the frequency range f = c / (4l ₁ ) different from the resonance frequency is also increased, and in the low frequency range of 500 Hz or less, The sound absorption coefficient can be increased over a wider range.

In the sound absorbing ceiling according to the fifth aspect of the present invention, the resonator type sound absorbing body according to any one of the first to fourth aspects and the porous sound absorbing body are suspended from the ceiling surface, so that a small number of types of resonance can be obtained. A sound absorbing ceiling having a high sound absorption coefficient in a wide sound range can be realized by the sound absorber and the porous sound absorbing body. That is,
The resonator type sound absorber has a sound range of a Helmholtz resonance frequency, a sound range of a frequency range based on the length of two sides of a substantially rectangular cross section of the cylinder, and a frequency range based on the axial length of the cylinder,
A wide variety of sound absorption characteristics can be obtained in the low range with a small number of resonator-type sound absorbers, and by combining with a porous sound absorber that has sound absorption characteristics in the middle and high range, a wide range from the low range to the high range. High sound absorption can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a resonator-type sound absorber according to an embodiment of the present invention.

FIG. 2 is a front view of a perforated plate of the resonator type sound absorber.

FIG. 3 is a side view of the resonator type sound absorber.

FIG. 4 is a view taken along line IV-IV in FIG. 2;

FIG. 5 is a view as seen from line VV in FIG. 3;

FIG. 6 is a diagram showing a relationship between a 1/3 octave band center frequency and a sound absorption coefficient of the resonator type sound absorber.

FIG. 7 is a diagram illustrating a state where the resonator-type sound absorber is suspended from a ceiling.

FIG. 8 is a sectional view of a resonator-type sound absorber according to another embodiment of the present invention.

FIG. 9 is a sectional view of a resonator-type sound absorber according to another embodiment of the present invention.

FIG. 10 is a sectional view of a resonator-type sound absorber according to another embodiment of the present invention.

FIG. 11 is a sectional view of a resonator-type sound absorber according to another embodiment of the present invention.

FIG. 12 is a sectional view of a resonator-type sound absorber according to another embodiment of the present invention.

FIG. 13 is a diagram illustrating a state where a porous sound absorber is suspended from a ceiling.

FIG. 14 is a sectional view of the porous sound absorber.

FIG. 15 is a diagram illustrating a state where the resonator-type sound absorber is connected in the axial direction and is suspended from a ceiling.

FIG. 16 is a diagram showing a state in which the resonator type sound absorbers are connected in a direction perpendicular to an axis and are suspended from a ceiling.

FIG. 17 is a diagram showing a state in which the resonator type sound absorber and the porous sound absorber are combined and connected in the axial direction, and are suspended from a ceiling.

FIG. 18 is a sectional view of a conventional resonator type sound absorber.

FIG. 19 is a sectional view of a resonator-type sound absorber using a conventional partition plate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylindrical body, 2 ... 1st partition plate, 3 ... 2nd partition plate, 4 ... Sealing lid, 5 ... Hanging hook, 10 ... Perforated plate, 10a ... Hole.

──────────────────────────────────────────────────続 き Continued on the front page (72) Shinya Kimura, Inventor 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Inside Okumura Gumi Co., Ltd. No. 2 No. 2 Okumura Gumi Co., Ltd. (56) References JP-A-54-77414 (JP, A) JP-A-53-21822 (JP, A) JP-A-49-32419 (JP, A) −78808 (JP, U) Fully open 1983-129911 (JP, U) Fully open 60-165517 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E04B 1/82 E04B 1/84 G10K 11/16

Claims (5)

(57) [Claims] 1. A tubular body having a substantially rectangular cross-section made of a perforated plate having a predetermined aperture ratio, and an inner periphery of the tubular body being parallel to an axis of the tubular body along a diagonal line of the tubular body. A first partition plate made of a sound insulating material provided; and an inner periphery of the cylindrical body being parallel to the axis of the cylindrical body and intersecting with the first partition plate along another diagonal line of the cylindrical body. A resonator-type sound absorber comprising: a second partition plate made of a sound insulating material provided in the above; and a sealing lid made of a sound insulating material for closing openings at both ends of the cylindrical body. 2. The resonator type sound absorber according to claim 1, wherein each of said plurality of spaces is provided in said cylinder in four spaces partitioned by said first and second partition plates, and has a smaller volume than said space. A resonator-type sound absorber comprising an adjusting partition made of a sound insulating material forming a space facing an inner surface of the cylindrical body. 3. The resonator-type sound absorber according to claim 1 or 2, the length of one side of the substantially rectangular cross-section of the tubular body and l _0, the first of said tubular body, the second The resonance frequency based on the volume of the four spaces partitioned by the partition plate, the aperture ratio of the perforated plate of the cylindrical body, and the length of the hole of the perforated plate is set to 500 Hz or less, and the frequency c / (4l ₀ ) (Where c is the speed of sound). 4. The resonator type sound absorber according to claim 3, wherein the axial length of the cylindrical body is l _1, and the first and second partition plates in the cylindrical body are divided into four parts. The resonance frequency based on the volume of the space, the aperture ratio of the perforated plate of the cylindrical body, and the length of the hole of the perforated plate is made not to coincide with the frequency c / (4l ₁ ) (where c is the speed of sound). A resonator type sound absorber characterized by the above-mentioned. 5. A sound absorbing ceiling, wherein the resonator type sound absorbing body according to claim 1 and a porous sound absorbing body are suspended from a ceiling surface.