JP2017116706A - Resonance absorption structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resonance absorption structure compactly made and capable of effectively absorbing middle/low frequency sound.SOLUTION: A resonance absorption structure 1 includes, arranged side-by-side in a width direction, a plurality of resonance tubes 2 extending in a depth direction with an end at one side open and an end at the other side closed. The cross sectional area of an opening 5 is 400 mmor more. The number of the plurality of resonance tubes 2 is 100 or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resonance sound absorbing structure.

  Transporters such as automobiles and trains are required to have high comfort for drivers and passengers. In order to improve this comfort, various measures for reducing noise such as road noise from the tire, engine noise, and wind noise during running have been adopted.

  In particular, in recent years, automobiles have been required to reduce the thickness and weight of components from the viewpoint of energy saving, and as a result, the above-mentioned noise is more likely to enter the interior of the vehicle interior.

  Therefore, in order to reduce these noises, it has been proposed to use a sound absorbing material made of a fiber material or sponge as an interior material of an automobile.

  However, these sound-absorbing materials are intended to absorb high-frequency sounds such as wind noise, and have low sound absorption performance for medium to low-frequency sounds such as road noise and engine noise. For this reason, if these sound absorbing materials are used to effectively absorb medium and low frequency sounds, the thickness of the sound absorbing material needs to be very thick, and it is used in a limited space such as an automobile casing. The problem is that this is difficult.

  On the other hand, a sound absorbing structure including tube resonance (air column resonance tube) has been proposed as a sound absorbing material for medium and low frequency sound other than fiber materials and sponges (see, for example, Patent Document 1).

  Patent Document 1 discloses a sound absorbing structure having a structure in which a plurality of cavities having different lengths in which one is closed and the other is opened are arranged adjacent to each other on the open side.

In such a resonance tube, resonance with a wavelength corresponding to the length of the tube is generated. Specifically, in a single-opened resonance tube, resonance occurs at a resonance wavelength λ _n of λ ₁ = 4L, λ ₂ = 4 / 3L,... Resonance of λ ₁ = 2L, λ ₂ = L... occurs and absorbs sound having these wavelengths.

JP 7-302087 A

  However, the sound absorbing structure of Patent Document 1 is intended to be used in a wide space such as for a house or a hall, and is not suitable for use in a limited space such as a vehicle compartment.

  An object of the present invention is to provide a resonant sound absorbing structure that is compact and capable of effectively absorbing medium and low frequency sound.

In the present invention [1], a plurality of resonance cylinders extending in at least the first direction, having one end opened and the other end closed is a second direction orthogonal to the first direction. Are arranged side by side, the cross-sectional area of the opening is 400 mm ² or less, and the number of the plurality of resonance tube portions is 100 or more.

According to this resonance sound absorbing structure, a plurality of resonance tube portions having one end opened and the other end closed are arranged side by side in the second direction, and the number thereof is 100. Since it is the above, it is excellent in the sound-absorbing property of middle and low frequency sound. Moreover, since the cross-sectional area of the opening is 400 mm ² or less, a compact structure can be achieved. Therefore, it is possible to efficiently absorb the sound of medium and low frequency sound in a limited space such as a vehicle cabin.

  The present invention [2] includes the resonant sound absorbing structure according to [1], wherein the length of the resonant tube portion is 20 mm or less in the first direction and the third direction orthogonal to the two directions.

  According to the resonance sound absorbing structure, a more compact structure can be achieved.

  The present invention [3] includes the resonant sound-absorbing structure according to [1] or [2], wherein the length in the first direction of the resonant cylinder portion is not less than 200 mm and not more than 1700 mm.

  According to the resonance sound absorbing structure, a more compact structure can be achieved.

  The present invention [4] provides the resonant sound absorbing structure according to any one of [1] to [3], wherein the resonant sound absorbing structure includes a plurality of the resonant cylinder portions having different lengths in the first direction. Contains.

  According to this resonance sound absorbing structure, it is possible to absorb a wide range of sounds with medium and low frequency sounds.

  According to the present invention [5], the first length of the resonance tube portion having the maximum first direction length is set to the first direction length of the resonance tube portion having the minimum first direction length. The resonance sound absorbing structure according to [4], wherein the ratio (maximum / minimum) is 1.4 or more and 4.0 or less.

  According to this resonance sound absorbing structure, it is possible to more reliably absorb a wide range of sounds with medium and low frequency sounds.

  The present invention [6] includes the resonant sound absorbing structure according to any one of [1] to [5], which is curved along the second direction.

  According to this resonance sound absorbing structure, it can also be arranged in a curved space.

  The present invention [7] is the resonant sound absorbing structure according to any one of [1] to [6], wherein at least one of the resonant tube portions has a curved portion that bends in a direction other than the first direction. Is included.

  According to this resonance sound absorbing structure, it can be arranged according to the shape of a complicated space.

  As for this invention [8], the said opening is arrange | positioned toward the 3rd direction orthogonal to the said 1st direction and the said 2 direction in the edge part of the said one side, Any one of [1]-[7] The resonance sound absorbing structure according to one item is included.

  According to this resonance sound absorbing structure, sound can be efficiently absorbed even when the resonance tube is disposed in a narrow space where it is difficult to absorb sound from the first direction while ensuring the length of the resonance cylinder portion in the first direction.

  The present invention [9] is any one of [1] to [8], wherein at least two of the resonance cylinders arranged adjacent to each other share a first wall that partitions the first direction. The resonance sound absorbing structure is included.

  According to this resonance sound absorbing structure, since a member for connecting the resonance cylinder portions arranged adjacent to each other is not required, the number of parts can be reduced and the size can be further reduced. Moreover, since the resonance cylinder parts arranged adjacent to each other are continuously integrated by the first wall, the strength of the resonance sound absorbing structure can be improved.

  The present invention [10] is any one of [1] to [9], wherein at least two of the resonance cylinder portions arranged adjacent to each other share a second wall that partitions the second direction. The resonance sound absorbing structure is included.

  According to this resonance sound absorbing structure, since a member for connecting the resonance cylinder portions arranged adjacent to each other is not required, the number of parts can be reduced and the size can be further reduced. In addition, since the resonance cylinder portions arranged adjacent to each other are continuously integrated by the second wall, the strength of the resonance sound absorbing structure can be improved.

  In the present invention [11], at least two of the resonance cylinders arranged adjacent to each other share a third wall that partitions the first direction and a third direction orthogonal to the two directions [1] to [10] The resonant sound absorbing structure according to any one of [10] is included.

  According to this resonance sound absorbing structure, since a member for connecting the resonance cylinder portions arranged adjacent to each other is not required, the number of parts can be reduced and the size can be further reduced. In addition, since the resonance cylinders arranged adjacent to each other are continuously integrated by the third wall, the strength of the resonance sound absorbing structure can be improved.

  The present invention [12] further includes an adhesive layer on at least one surface in the third direction orthogonal to the first direction and the two directions of the resonant sound-absorbing structure, according to any one of [1] to [11]. The resonance sound absorbing structure according to the item is included.

  According to this resonance sound absorbing structure, it can be easily attached to a space where sound absorption is desired.

  This invention [13] contains the resonance sound absorption structure as described in any one of [1]-[12] which is an interior material of a motor vehicle.

  According to this resonance sound absorbing structure, it can be compactly installed in the interior of the automobile and the comfort of the automobile can be improved.

  According to the sound absorbing structure of the present invention, it is compact and can effectively absorb medium and low frequency sound. Therefore, it is possible to absorb medium and low frequency sound in a limited space such as a vehicle cabin.

FIG. 1 shows a perspective view of a first embodiment of a sound absorbing structure of the present invention. 2A to 2C are partially enlarged views of the sound absorbing structure shown in FIG. 1, FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a rear view. 3A to 3B show a modification of the first embodiment (a configuration in which the resonance tube has a substantially rectangular frame shape), FIG. 3A is a perspective view, and FIG. 3B is a front view. 4A to 4B show a modification of the first embodiment (a configuration including two types of longitudinally-resonating resonant tubes), FIG. 4A is a perspective view, and FIG. 4B is a plan view. FIGS. 5A to 5B show a modification of the first embodiment (a configuration in which two resonance tubes are provided in the vertical direction), FIG. 5A is a perspective view, and FIG. 5B is a front view. FIG. 6: shows the front view of the modification (form which curves along the left-right direction) of 1st Embodiment. 7A to 7C show a curved pipe, FIG. 7A shows an L-shaped pipe, FIG. 7B shows a U-shaped pipe, and FIG. 7C shows a U-shaped pipe whose external shape is I-type. 8A to 8D show a second embodiment of the sound absorbing structure of the present invention, FIG. 8A is a plan view, FIG. 8B is a bottom view, and FIG. 8C is a cross-sectional view taken along line AA in FIG. 8D shows a cross-sectional view taken along the line BB of FIG. 8A. FIG. 9 shows an automobile provided with the sound absorbing structure shown in FIG. 8 and a partially enlarged view thereof. FIG. 10 shows a measurement graph of the sound absorption rate of Examples 1 and 2 and Comparative Example 1. FIG. 11 shows a measurement graph of the sound absorption coefficient of Example 3.

  In FIG. 2A, the vertical direction of the paper surface is the front-back direction (first direction), the lower side of the paper surface is the front side (one side in the first direction), and the upper side of the paper surface is the rear side (the other side in the first direction). The left and right direction on the paper surface is the left and right direction (second direction orthogonal to the first direction), the left side on the paper surface is the left side (second side in the second direction), and the right side on the paper surface is the right side (the other side in the second direction). The paper thickness direction is a vertical direction (a third direction orthogonal to the first direction and the second direction), the front side of the paper is the upper side (one side in the third direction), and the back side of the paper is the lower side (the other side in the third direction). is there. Drawings other than FIG. 2A also conform to the direction of FIG. 2A.

(First embodiment)
As shown in FIG. 1, the resonance sound absorbing structure 1 (also referred to simply as a sound absorbing structure) according to the first embodiment of the present invention includes a plurality of resonance tubes 2 as an example of a resonance cylinder portion.

  As shown in FIGS. 1 and 2A, the resonance tube 2 has a tubular structure extending in the front-rear direction, the front end portion is open, and the rear end portion is closed. That is, the resonance tube 2 has a bottomed cylindrical shape that opens at the front end. Specifically, the resonance tube 2 is integrally provided with a tube portion 3 and a lid portion 4 that closes the rear end portion of the tube portion 3.

  As shown in FIG. 2B, the pipe portion 3 has a cylindrical shape extending in the front-rear direction having a substantially annular shape when viewed from the front, and the front end portion and the rear end portion thereof are open. The tube portion 3 is formed so that its outer diameter shape and inner diameter shape are the same from the front end portion to the rear end portion.

  2A and 2C, the lid portion 4 is disposed at the rear end portion of the tube portion 3 so as to close the opening of the rear end portion of the tube portion 3. The lid portion 4 has a substantially circular disc shape when viewed from the front, and the size thereof matches the inner diameter of the tube portion 3.

  As shown in FIGS. 2A and 2B, an opening 5 that opens toward the front side is formed at the front end portion of the resonance tube 2, that is, the front end portion of the tube portion 3. The shape of the opening 5 is substantially circular when viewed from the front, and matches the inner diameter of the tube portion 3.

  The material forming the resonance tube 2 (the tube portion 3 and the lid portion 4) is not limited, and examples thereof include synthetic resin (plastic), paper, metal, and composite materials thereof.

  Examples of synthetic resins include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, styrene resins such as polystyrene, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-styrene copolymers, Examples include vinyl chloride.

  Examples of paper include craft paper and Japanese paper.

  Examples of the metal include aluminum, iron, zinc, nickel, copper, and stainless steel.

  Preferably, a synthetic resin and a metal are mentioned, More preferably, polyolefin and aluminum are mentioned.

The cross-sectional area of the opening 5 (opening) (that is, the inner diameter area of the tube portion 3; see the hatched portion in FIG. 2A) is 400 mm ² or less in a front view. Preferably, it is 300 mm ² or less, more preferably 80 mm ² or less. For example, it is 10 mm ² or more, preferably 30 mm ² or more. By making the cross-sectional area of the opening 5 not more than the above upper limit, the sound absorbing structure 1 can be made compact. Moreover, by making the cross-sectional area of the opening part 5 more than the said minimum, while being excellent in productivity and making sound absorption favorable, the intensity | strength of the sound-absorbing structure 1 can be maintained.

  The diameter D of the opening 5 (that is, the inner diameter D of the resonance tube 2; see FIG. 2B) is, for example, 20 mm or less, preferably 10 mm or less, more preferably 8 mm or less, and for example, 1 mm or more, preferably Is 3 mm or more.

  The vertical length H of the resonance tube 2 (that is, the outer diameter of the tube portion 3; see FIG. 2B) is, for example, 20 mm or less, preferably 10 mm or less, more preferably 9 mm or less, and for example, 1 mm. As mentioned above, Preferably, it is 3 mm or more. By setting the length H in the vertical direction of the resonance tube 2 to be equal to or less than the above upper limit, a compact structure can be obtained, and the sound absorbing structure 1 can be efficiently arranged in the passenger compartment of the automobile.

  The longitudinal length L1 (see FIG. 2A) of the resonance tube 2 is, for example, 200 mm or more, preferably 300 mm or more, and, for example, 1700 mm or less, preferably 1000 mm or less, more preferably 500 mm or less. . By setting the length L1 in the front-rear direction within the above range, it is possible to more reliably absorb the mid-low frequency sound.

  The thickness T of the resonance tube 2 (that is, the thickness of the tube portion 3 and the lid portion 4; see FIG. 2B) is, for example, 0.1 mm or more, preferably 0.2 mm or more, and, for example, 3 mm or less, preferably Is 1 mm or less.

  The plurality of resonance tubes 2 are arranged side by side in the left-right direction. Specifically, the plurality of resonance tubes 2 are linearly aligned in the left-right direction so that the adjacent resonance tubes 2 are in contact with each other.

  The number of the resonance tubes 2 is 100 or more, preferably 150 or more, more preferably 200 or more. For example, it is 500 or less, preferably 300 or less. By setting the number of the resonance tubes 2 to be equal to or more than the above lower limit, it is possible to more effectively absorb the medium / low frequency sound. Moreover, the sound absorption structure 1 can be made into a compact structure by making the number of the resonance tubes 2 below the upper limit.

  The length in the front-rear direction, the length in the left-right direction, and the length in the vertical direction of the plurality of resonance tubes 2 are all substantially the same. The sound absorbing structure 1 has a substantially rectangular shape in plan view extending in the left-right direction in plan view. That is, the plurality of resonance tubes 2 are arranged so that the front end edges of the respective sound absorbing structures 1 are flush with each other in the left-right direction in plan view, and the rear end edges of the respective sound absorbing structures 1 are surfaces in the left-right direction. They are aligned so as to be one. Further, the plurality of resonance tubes 2 are aligned and arranged so that the vertical positions of these upper end edges coincide with each other and the vertical positions of these lower end edges coincide.

  The left-right direction length L2 (refer FIG. 1) of the sound-absorbing structure 1 is 500 mm or more, for example, Preferably, it is 1000 mm or more, for example, 3000 mm or less, Preferably, it is 2000 mm or less, More preferably, it is 1700 mm or less. is there. The longitudinal length and the vertical length of the sound absorbing structure 1 are the same as the longitudinal length L1 and the vertical length H of the resonance tube 2, respectively.

  The sound absorbing structure 1 can be manufactured, for example, by connecting a plurality of resonance tubes 2 using a fixing member such as an adhesive sheet, a connecting band, a screw, or a rivet. Further, when the sound absorbing structure 1 is made of a synthetic resin, it can be integrally formed by extrusion molding or the like.

  The sound absorbing structure 1 can be used for various members that need to absorb medium and low frequency sound. Preferably, it is used as an interior material for a transport device such as an automobile or train. Preferably, it is used as an automobile interior material. Examples of automobile interior materials include roof materials (ceiling materials), floor members, and trunk room interior materials.

(Function and effect)
The sound absorbing structure 1 has a plurality of resonance tubes 2 that extend in the front-rear direction, open at the front end and closed at the rear end, and are arranged adjacent to each other in the left-right direction. 400 mm ² or less, and the number of resonance tubes 2 is 100 or more. Therefore, it is excellent in sound absorption of medium and low frequency sound while having a compact structure.

  In particular, such a single-opened resonance tube 2 can absorb sound by resonating a frequency sound approximately calculated by the following equation according to its length L1.

Formula 1

(Where f is the frequency (Hz), c is the speed of sound (m / s), L is the longitudinal length L1 (m) of the resonance tube 2, and n is an integer of 0 or more.)
Specifically, for example, when L is 300 mm, the medium and low frequency sounds in the vicinity of 290 Hz, 860 Hz, 1440 Hz, etc. can be resonated and absorbed at room temperature, and in particular, the sound absorption in the vicinity of 290 Hz, which is the lowest frequency sound. High nature.

  Therefore, when the length L1 of the resonance tube 2 in the front-rear direction is, for example, 200 to 1700 mm, the sound absorbing property of 50 Hz to 500 Hz is particularly excellent.

  And since this sound absorption structure 1 is provided with 100 or more resonance tubes 2 whose opening cross-sectional area is less than or equal to specific, these resonance tubes 2 synergistically influence each other to absorb sound of the above frequency more effectively. And a compact structure can be adopted.

  In particular, the sound absorbing structure 1 can be compactly attached to the interior of an automobile as an automobile interior material, and the comfort of the automobile can be improved.

(Modification)
In the embodiment shown in FIG. 1, the tube portion 3 has a substantially circular shape in front view. For example, as shown in FIG. 3, the tube portion 3 has a substantially rectangular frame shape (more specifically, in front view). Can also have a substantially square shape when viewed from the front. That is, the tube part 3 can have a rectangular tube shape.

  In this case, the horizontal length W (see FIG. 3B) of the resonance tube 2 is the same as the vertical length H of the resonance tube 2, for example, 20 mm or less, preferably 10 mm or less, more preferably 9 mm or less. Also, for example, 1 mm or more, preferably 3 mm or more.

  Also, the vertical length D1 and the horizontal length D2 of the opening 5 of the resonance tube 2 are the same as the inner diameter D of the resonance tube 2 in FIG. 2B, for example, 20 mm or less, preferably 10 mm or less, More preferably, it is 8 mm or less, for example, 1 mm or more, preferably 3 mm or more.

  The sound absorbing structure 1 shown in FIG. 3 has the same configuration as the sound absorbing structure 1 shown in FIGS. 1 and 2 except for the above.

  In the embodiment shown in FIG. 1, the sound absorbing structure 1 includes the resonance tubes 2 having the same length in the front-rear direction. For example, as shown in FIGS. 4A and 4B, the sound absorbing structure 1 is A plurality of resonance tubes 2 having different lengths in the front-rear direction can also be provided.

  Specifically, the sound absorbing structure 1 shown in FIGS. 4A and 4B includes two types of longitudinally-resonating resonance tubes 2. That is, the sound absorbing structure 1 includes a plurality of relatively long resonance tubes 2 in the left-right direction and a plurality of relatively short resonance tubes 2. The plurality of relatively long resonance tubes 2 are arranged adjacent to each other, and the plurality of relatively short resonance tubes 2 are arranged adjacent to each other. The relatively long resonance tubes 2 are adjacent to the relatively short resonance tubes 2 at the center in the left-right direction.

  According to the sound absorbing structure 1 of FIGS. 4A and 4B, it is possible to absorb a wide range of frequencies with medium to low frequency sounds according to the longitudinal length L1 of the resonance tube 2.

  The ratio (Lmax / Lmin) of the longitudinal length (Lmax) of the resonant tube 2 with the largest longitudinal length L1 to the longitudinal length (Lmin) of the resonant tube 2 with the smallest longitudinal length L1 is, for example, 1.4 or more, preferably 1.5 or more, for example, 4.0 or less, preferably 2.0 or less. By setting the above ratio within the above range, it is possible to more reliably absorb a wide range of sounds with medium to low frequency sounds. In particular, by making the ratio less than or equal to the above upper limit, it is possible to suppress an excessive difference (over 2 octaves) in the frequency range of a plurality of sounds to be absorbed, and to smoothly absorb sound in a wide frequency range without leaking the range. Can be made possible. On the other hand, by setting the ratio to be equal to or higher than the lower limit, it is possible to further widen the frequency sound range to be absorbed.

  Lmin is, for example, 200 mm or more, preferably 300 mm or more. Moreover, Lmax is 1700 mm or less, for example, Preferably, it is 1000 mm or less, More preferably, it is 800 mm or less.

  In the embodiment shown in FIGS. 4A and 4B, the sound absorbing structure 1 includes two types of resonance tubes 2 having lengths in the front-rear direction. For example, although not shown, the sound absorbing structure 1 has three or more types. A resonance tube 2 having a length in the front-rear direction can also be provided. In this case, it is preferable to adjust the length L1 in the front-rear direction of each resonance tube 2 so that a frequency within a maximum of 2 octaves can be absorbed every 1/2 to 1/3 octave.

  In the embodiment of FIG. 1, the horizontal length L1 and the vertical length H of the plurality of resonance tubes 2 are all substantially the same. For example, although not shown, The direction length and / or the vertical length may be different from each other.

  3A and 3B, the sound absorbing structure 1 can also include an adhesive layer 6 on at least one of the upper surface and the lower surface.

  The adhesive layer 6 is formed from an adhesive composition.

  The adhesive composition is preferably a pressure sensitive adhesive composition.

  Specific examples of the pressure-sensitive adhesive composition include rubber compositions (natural rubber compositions and synthetic rubber compositions) such as epoxy resin compositions.

  As a synthetic rubber composition, the acrylic rubber composition containing an acrylic rubber is mentioned, for example. The acrylic rubber can be obtained by polymerizing a monomer component mainly composed of (meth) acrylic acid ester.

  The thickness of the adhesive layer 6 is, for example, 50 μm or more, preferably 100 μm or more, and for example, 2000 μm or less, preferably 1000 μm or less.

  By providing such an adhesive layer 6, it can be easily attached to a space where sound absorption is desired.

  In the embodiment shown in FIG. 1, the sound absorbing structure 1 includes a single (one layer) resonance tube 2 in the vertical direction. For example, as shown in FIGS. 5A and 5B, the sound absorbing structure 1 Can also include a plurality (two layers) of resonance tubes 2 in the vertical direction.

  In the embodiment of FIGS. 5A and 5B, the vertical length of the sound absorbing structure 1, that is, the total vertical length of the plurality of resonance tubes 2 is preferably 20 mm or less. Thereby, the sound absorption structure 1 can be made into a compact structure, and the sound absorption structure 1 can be efficiently arrange | positioned in the compartment of a motor vehicle.

  In the embodiment of FIGS. 5A and 5B, two layers of resonance tubes 2 are provided in the vertical direction. However, the number of resonance tubes 2 in the vertical direction is not limited, and may be, for example, three or more layers. .

  In the embodiment of FIG. 1, the plurality of resonance tubes 2 are arranged in a straight line in the left-right direction. For example, as shown in FIG. 6, the plurality of resonance tubes 2 are arranged in the left-right direction. It can also be arranged to be curved.

  According to the sound absorbing structure 1 shown in FIG. 6, the sound absorbing structure 1 can also be disposed in a curved space.

  In the embodiment shown in FIG. 6, all of the plurality of resonance tubes 2 are formed so as to extend linearly in the front-rear direction. For example, the sound absorbing structure 1 is a curved tube 7 shown in FIGS. 7A to 7C. Can be provided.

  The bent tube 7 has a tubular structure in which one end is open and the other end is closed. Specifically, a linear portion 21 extending in the front-rear direction having an opening 5 at the front end, a curved portion 22 that bends in the left-right direction or the vertical direction, and a lid portion 4 that closes the other end of the curved pipe 7 are provided. The other end portion 23 is provided. More specifically, an L-shaped tube (or J-shaped tube) shown in FIG. 7A, a U-shaped tube shown in FIG. 7B, and a U-shaped tube whose external shape is I-type and whose internal shape is U-shaped are shown in FIG. 7C. It is done.

  The number of the bent portions 22 of the bent tube 7 is preferably 1 from the viewpoint of resonance.

  Since the sound absorbing structure 1 includes the curved pipe 7, the length of the sound absorbing structure 1 in the front-rear direction can be partially shortened and arranged according to the shape of a complicated space.

(Second Embodiment)
As shown in FIGS. 8A to 8D, the sound absorbing structure 1 of the second embodiment of the present invention has a substantially box shape, and includes a front wall 11 as an example of the first wall and an example of the first wall. Rear wall 12, left wall 13, right wall 14, upper wall 15 as an example of a third wall, lower wall 16 as an example of a third wall, and a plurality of partition plates as an example of a second wall 17. In addition, in each subsequent figure, the same code | symbol is attached | subjected to the member similar to the said 1st Embodiment, and the description is abbreviate | omitted.

  The front wall 11 has a substantially flat plate shape extending in the left-right direction.

  The rear wall 12 is disposed on the rear side of the front wall 11 so as to face the front wall 11 with a space therebetween, and partitions the space in the front-rear direction together with the front wall 11. The rear wall 12 has a substantially flat plate shape extending in the left-right direction, and has the same shape as the front wall 11. The rear wall 12 coincides with the front wall 11 when projected in the front-rear direction.

  The left wall 13 has a substantially flat plate shape in which the left end edge of the front wall 11 and the left end edge of the rear wall 12 are installed and extend in the front-rear direction.

  The right wall 14 is disposed on the right side of the left wall 13 so as to face the left wall 13 with a space therebetween, and the right end edge of the front wall 11 and the right end edge of the rear wall 12 are installed. The right wall 14 has a substantially flat plate shape extending in the front-rear direction, and has the same shape as the left wall 13. The right wall 14 coincides with the left wall 13 when projected in the left-right direction.

  The upper wall 15 bridges the upper edge of the front wall 11 and the upper edge of the rear wall 12, and bridges the upper edge of the left wall 13 and the upper edge of the right wall 14. The upper wall 15 has a substantially flat plate shape extending in the front-rear and left-right directions.

  The lower wall 16 is disposed on the lower side of the upper wall 15 so as to face the upper wall 15 with a space therebetween, and partitions the space in the vertical direction together with the upper wall 15. The lower wall 16 spans the lower end of the front wall 11 and the lower end of the rear wall 12, and spans the lower end edge of the left wall 13 and the lower end edge of the right wall 14. The lower wall 16 has a substantially flat plate shape extending in the front-rear direction, and is formed so that the length in the front-rear direction is slightly shorter than the length in the front-rear direction of the upper wall 15. The rear end edge of the lower wall 16 is continuous with the lower end edge of the rear wall 12, while the front end edge of the lower wall 16 is not continuous with the lower end edge of the front wall 11 and is slightly smaller than the lower end edge of the front wall 11. Located on the back side. Thereby, an opening 5 (described later) is formed.

  The plurality of partition plates 17 are arranged between the left wall 13 and the right wall 14 so as to be approximately equally divided in the left-right direction, and partition the space in the left-right direction. The plurality of partition plates 17 have a flat plate shape extending in the front-rear direction, and are installed on the front wall 11 and the rear wall 12. The plurality of partition plates 17 divide the internal space composed of the front wall 11, the rear wall 12, the left wall 13, the right wall 14, the upper wall 15 and the lower wall 16 into a cylindrical shape extending in the front-rear direction. A plurality of resonance cylinder portions 18 are configured.

  The resonance cylinder 18 includes a front wall 11, a rear wall 12, an upper wall 15, a lower wall 16, and two partition plates 17 adjacent to each other, and has a rectangular tube shape extending in the front-rear direction. Of the plurality of resonance cylinder portions 18, the resonance cylinder portion 18 located on the leftmost side is adjacent to the front wall 11, the rear wall 12, the upper wall 15, the lower wall 16, the left wall 13, and the left wall 13. A partition plate 17 is provided. The resonance cylinder portion 18 located on the rightmost side includes a front wall 11, a rear wall 12, an upper wall 15, a lower wall 16, a right wall 14, and a partition plate 17 adjacent to the right wall 14.

  Two adjacent resonance cylinder portions 18 share one partition plate 17 existing therebetween. Further, all the resonance tube portions 18 share one front wall 11, one rear wall 12, one upper wall 15, and one lower wall 16.

  In the resonance cylinder part 18, the opening part 5 opened toward the lower side is formed in the front end part. The opening 5 is formed in a substantially rectangular shape in plan view.

  The cross-sectional area of the opening 5 is the same as the cross-sectional area of the opening 5 of the first embodiment.

  The front-rear direction length D ′ (see FIG. 8B) of the opening 5 is, for example, not less than 80% and not more than 120% of the length of D1. By setting D ′ within the above range, it is possible to effectively absorb sound into the resonance cylinder portion 18 and improve sound absorption performance. The length in the left-right direction of the opening 5 is the same as the length D2 in the left-right direction on the inner side of the resonance cylinder portion 18.

  The longitudinal length L1 of the resonance cylinder portion 18 is the same as the longitudinal length L1 of the resonance tube 2 of the first embodiment.

  The lengths of the outer dimensions (the outer front-rear direction length H and the outer left-right direction length W) of the resonance tube portion 18 are respectively the vertical length H or the left-right direction length W of the resonance tube 2 of the first embodiment. It is the same.

  The lengths of the inner dimensions (inner up / down direction length D1 and inner left / right direction length D2) of the resonance cylinder 18 are the same as the inner dimension of the resonance tube 2 in the up / down direction length D1 and the left / right direction length D2, respectively. is there.

  The thickness of each wall (the front wall 11, the rear wall 12, the left wall 13, the right wall 14, the upper wall 15, the lower wall 16, and the partition plate 17) is the same as the thickness T of the resonance tube 2 of the first embodiment. .

  The material constituting each wall is the same as the material of the resonance tube 2 of the first embodiment. From the viewpoint of moldability and lightness, a synthetic resin is preferable, and a polyolefin is more preferable.

  The left-right direction length L2 of the sound-absorbing structure 1 is, for example, 500 mm or more, preferably 1000 mm or more, and for example, 2000 mm or less, preferably 1500 mm or less. The longitudinal length and the vertical length of the sound absorbing structure 1 are the same as the outer longitudinal length L1 and the vertical length H of the resonance cylinder portion 18, respectively.

  The sound absorbing structure 1 can be used for various members that need to absorb medium and low frequency sound. Preferably, it is used as an interior material for a transport device such as an automobile or train. Examples of the interior material for the transport aircraft include a roof material (ceiling material), a floor member, and an interior material for a trunk room.

  In particular, the sound absorbing structure 1 is preferably used as a roof material of an automobile. In this case, for example, as shown in FIG. 9, a roof panel 19 (steel plate) of the vehicle and a roof interior material 20 (resin sheet or foamed sheet) disposed opposite to each other with a space on the vehicle compartment side of the roof panel 19. Between them.

  Specifically, the sound absorbing structure 1 is arranged so that the vertical direction of the sound absorbing structure 1 coincides with the vertical direction of the automobile. That is, it arrange | positions so that the opening part 5 may open toward lower side (namely, vehicle interior side). The sound absorbing structure 1 is arranged so that the front-rear direction of the sound absorbing structure 1 coincides with the left-right direction of the automobile.

  As a result, the sound absorbing structure 1 having a larger area is arranged in a limited space of the automobile, so that medium and low frequency sound (road noise, engine noise, etc.) entering the passenger compartment is more effectively obtained. Can absorb sound. Moreover, since this sound absorption structure 1 is a compact structure, even if it arrange | positions in the space near the ceiling of the said motor vehicle, it does not press too much the interior space. In particular, if the vertical length of the sound absorbing structure 1 is 20 mm or less, there is usually a case where a predetermined space may exist between the roof panel and the ceiling interior material. The sound-absorbing structure 1 can be disposed while reducing the depression of the vehicle interior to the vehicle interior (that is, the position of the ceiling interior material is kept high).

  Further, even if the sound absorbing structure 1 is arranged in a narrow space near the ceiling of the passenger compartment, the opening 5 opens downward, so that the sound absorption structure 1 enters the passenger compartment and reflects off the ceiling. High frequency sound can be absorbed efficiently.

  Therefore, the sound absorbing structure 1 can be compactly attached to the interior of the automobile as an automobile interior material, and the comfort of the automobile can be improved more reliably.

(Function and effect)
The sound absorbing structure 1 of the second embodiment also has the same effects as the sound absorbing structure 1 of the first embodiment.

  Moreover, in this sound-absorbing structure 1, the opening part 5 is arrange | positioned toward the lower side in the front-end part.

  For this reason, even if it arrange | positions in the narrow space (for example, compartment of a motor vehicle) where it is difficult to absorb sound from the front-back direction, ensuring the front-back direction of the resonance cylinder part 18, it can absorb sound efficiently.

  In the sound absorbing structure 1, the two resonance cylinders 18 arranged adjacent to each other share one front wall 11 and one rear wall 12 that partition the front-rear direction.

  For this reason, since the member for connecting the resonance cylinder parts 18 mutually adjacently arranged is not required, while being able to reduce a number of parts, it can be made still more compact. In addition, since the resonance cylinder portions 18 arranged adjacent to each other are continuously integrated by the front wall 11 and the rear wall 12, the strength of the sound absorbing structure 1 can be improved.

  In the sound absorbing structure 1, the two resonance cylinders 18 arranged adjacent to each other share one partition plate 17 that partitions the left-right direction.

  For this reason, since the member for connecting the resonance cylinder parts 18 mutually adjacently arranged is not required, while being able to reduce a number of parts, it can be made still more compact. Moreover, since the resonance cylinder portions 18 disposed adjacent to each other are continuously integrated by the partition plate 17, the strength of the sound absorbing structure 1 can be improved.

  In the sound absorbing structure 1, the two resonance cylinders 18 arranged adjacent to each other share one upper wall 15 and one lower wall 16 that partition the vertical direction.

  For this reason, since the member for connecting the resonance cylinder parts 18 mutually adjacently arranged is not required, while being able to reduce a number of parts, it can be made still more compact. Moreover, since the resonance cylinder portions 18 arranged adjacent to each other are continuously integrated by the upper wall 15 and the lower wall 16, the strength of the sound absorbing structure 1 can be improved.

(Modification)
In the embodiment of FIGS. 8A to 8D, the sound absorbing structure 1 is provided with the resonance cylinder portion 18 having the same length in the front-rear direction. For example, although not shown, the sound absorbing structure 1 has a plurality of different front and rear directions. A length of the resonant cylinder 18 can also be provided.

  In the embodiment of FIGS. 8A to 8D, the lengths in the left-right direction and the length in the vertical direction of the plurality of resonance cylinders 18 are all substantially the same. The horizontal length and / or the vertical length of the cylindrical portion 18 may be different from each other.

  8A to 8D, the sound absorbing structure 1 can also include an adhesive layer 6 on at least one of the upper surface and the lower surface, as indicated by the phantom lines in FIGS. 8C and 8D.

  In the embodiment of FIG. 9, the sound absorbing structure 1 is arranged in the space so that the front-rear direction of the sound absorbing structure 1 coincides with the left-right direction of the automobile. The front-rear direction can be arranged in the space so as to coincide with the front-rear direction of the automobile. Further, the sound absorbing structure 1 can be divided into a plurality of parts depending on the size of the automobile.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, this invention is not limited to an Example and a comparative example at all. In addition, specific numerical values such as a blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned “Mode for Carrying Out the Invention”, and a blending ratio corresponding to them ( Substituting the upper limit value (numerical value defined as “less than” or “less than”) or the lower limit value (number defined as “greater than” or “exceeded”) such as content ratio), physical property values, parameters, etc. be able to.

Example 1
A sound-absorbing structure was manufactured by arranging 200 annular aluminum tubes having a front end opened and a rear end closed so as to be adjacent to each other in the left-right direction (see FIG. 1).

The aluminum tube used (thickness T0.2 mm) has a longitudinal length L1 of 300 mm, an inner diameter D of 8.0 mm, and a vertical length H (outer diameter) of 8.4 mm. The area of the opening was 50 mm ² .

Example 2
A sound-absorbing structure was manufactured by arranging 100 annular aluminum tubes having a front end opened and a rear end closed so as to be adjacent to each other in the left-right direction (see FIG. 1).

The aluminum tube used (thickness T0.2 mm) has a longitudinal length L1 of 300 mm, an inner diameter D of 16.0 mm, and a vertical length H (outer diameter) of 16.4 mm. The area of the opening was 200 mm ² .

Comparative Example 1
A sound absorbing structure was manufactured by arranging 50 annular aluminum tubes having a front end opened and a rear end closed so as to be adjacent to each other in the left-right direction (see FIG. 1).

The used aluminum tube (thickness T0.2 mm) has a longitudinal length L1 of 300 mm, an inner diameter D of 32.0 mm, and a vertical length H (outer diameter) of 32.4 mm. The area of the opening was 803 mm ² .

Example 3
Using a plate material made of polypropylene (PP) having a thickness of T0.5 mm, a rectangular tube-shaped resonance tube A having an opening cross-sectional area of 100 mm ² , a vertical length (H) of 11 mm, and a longitudinal length (Lmax) of 500 mm And 100 resonance tubes A were arranged adjacent to each other in the left-right direction.

  Further, in the resonance tube A, a resonance tube B having a longitudinal length (Lmin) changed to 330 mm was produced, and 100 resonance tubes B were arranged adjacent to each other in the left-right direction.

  The assembly of the resonance tube A and the assembly of the resonance tube B were disposed adjacent to each other in the left-right direction to manufacture a sound absorbing structure (see FIGS. 4A and 4B).

(Measurement of sound absorption rate)
The sound absorption rate of these sound absorbing structures was measured by the reverberation chamber method. That is, each sound absorbing structure was measured in a room with a volume of 9 m ³ . In addition, about each Example and the comparative example, since the total cross-sectional areas of the opening part of these sound absorption structures differ from each other, the sound absorption coefficient converted so that these total cross-sectional areas became mutually the same was calculated | required. Specifically, the sound absorption rate was converted based on the total cross-sectional area of the opening of Example 2 (converted to a thickness of 16 mm). The results are shown in FIG. 10 and FIG.

  From the results of FIG. 10, the sound absorbing structures of Examples 1 and 2 are generally excellent in sound absorption coefficient (particularly around the frequency of 290 Hz to 300 Hz) as compared with the sound absorbing structure of Comparative Example 1. I understand.

  Moreover, it can be seen from the results of FIG. 11 that the sound absorbing structure of Example 3 is wide in the low frequency sound range of 150 Hz to 250 Hz and exhibits a good sound absorbing effect.

DESCRIPTION OF SYMBOLS 1 Sound absorption structure 2 Resonance pipe 5 Opening part 6 Adhesive layer 7 Curved pipe 11 Front wall 12 Rear wall 15 Upper wall 16 Lower wall 17 Partition plate 18 Resonance cylinder part

Claims (13)

A plurality of resonance tube portions that extend in at least the first direction, open at one end, and close at the other end are arranged side by side in a second direction orthogonal to the first direction. ,
A cross-sectional area of the opening is 400 mm ² or less;
The resonance sound absorbing structure according to claim 1, wherein the number of the plurality of resonance cylinder portions is 100 or more.   2. The resonance sound absorbing structure according to claim 1, wherein a length of the resonance cylinder portion is 20 mm or less in the first direction and a third direction orthogonal to the two directions.   The resonance sound absorbing structure according to claim 1 or 2, wherein the length in the first direction of the resonance cylinder portion is 200 mm or more and 1700 mm or less.   The resonance sound absorbing structure according to any one of claims 1 to 3, wherein the resonance sound absorbing structure includes a plurality of the resonance cylinder portions having different lengths in the first direction.   The ratio (maximum / minimum) of the first direction length of the resonance cylinder portion having the maximum first direction length to the first direction length of the resonance cylinder portion having the minimum first direction length. The resonance sound absorbing structure according to claim 4, wherein the resonance sound absorbing structure is 1.4 or more and 4.0 or less.   The resonance sound absorbing structure according to any one of claims 1 to 5, wherein the structure is curved along the second direction.   The resonance sound absorbing structure according to any one of claims 1 to 6, wherein at least one of the plurality of resonance tube portions has a curved portion that bends in a direction other than the first direction.   The said opening is arrange | positioned in the 3rd direction orthogonal to the said 1st direction and the said 2 direction in the edge part of the said one side, The Claim 1 characterized by the above-mentioned. The resonance sound absorbing structure as described.   The resonance sound absorption according to any one of claims 1 to 8, wherein at least two of the resonance tube portions arranged adjacent to each other share a first wall that partitions the first direction. Structure.   The resonance sound absorption according to any one of claims 1 to 9, wherein at least two of the resonance tube portions arranged adjacent to each other share a second wall that partitions the second direction. Structure.   The at least two resonance cylinders arranged adjacent to each other share a third wall that partitions the first direction and a third direction orthogonal to the two directions. The resonance sound-absorbing structure according to any one of the above.   The adhesive layer is further provided on at least one surface of the third direction orthogonal to the first direction and the two directions of the resonance sound absorbing structure. Resonant sound absorbing structure.   It is an interior material of a motor vehicle, The resonance sound absorption structure as described in any one of Claims 1-12 characterized by the above-mentioned.

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