Soundproof structure and soundproof system
10789929 ยท 2020-09-29
Assignee
Inventors
Cpc classification
F24F13/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24F13/24
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24F2013/245
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
G10K11/16
PHYSICS
F24F13/24
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24F13/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A soundproof structure has two or more soundproof units. Each of the soundproof units has an outer shell having a cylindrical shape, has a hollow inner space inside the outer shell, and has a first opening portion opened to outside on a surface that is one end portion of the outer shell in an axis direction of the cylindrical shape. The two soundproof units adjacent to each other are disposed in the axis direction such that the first opening portions face each other. The first opening portions facing each other are spaced apart from each other in the axis direction. An average distance in the axis direction between the first opening portions facing each other is less than 20 mm. Accordingly, there are provided a soundproof structure and a soundproof system which can insulate sounds on the low frequency side with a simple configuration, are small and lightweight, and can easily change the frequency characteristics.
Claims
1. A soundproof structure, comprising: two or more soundproof units, wherein each of the soundproof units has an outer shell having a cylindrical shape, has a hollow inner space inside the outer shell which is not filled with an acoustic material, and has a first opening portion opened to outside on a surface that is one end portion of the outer shell in an axis direction of the cylindrical shape and a second end portion opposite the one end portion, wherein the second end portion is a closed surface, the two soundproof units adjacent to each other are disposed in the axis direction such that the first opening portions face each other, the first opening portions facing each other are spaced apart from each other in the axis direction, and an average distance in the axis direction between the first opening portions facing each other is less than 20 mm, which is significantly less than a length L between the second end portion and the one end portion.
2. The soundproof structure according to claim 1, wherein a lid member that separates the inner space from the outside is provided on a surface that is the other end portion of the outer shell in the axis direction of the cylindrical shape.
3. The soundproof structure according to claim 2, wherein the lid member blocks the inner space of the outer shell from the outer space.
4. The soundproof structure according to claim 1, wherein a second opening portion smaller in size than the first opening portion is provided on a surface that is the other end portion of the outer shell in the axis direction of the cylindrical shape.
5. The soundproof structure according to claim 1, wherein the outer shell blocks the inner space is blocked from the outside except for two surfaces that are both end portions of the outer shell in the axis direction of the cylindrical shape.
6. The soundproof structure according to claim 1, wherein the outer shell has one or more second opening portions smaller in size than the first opening portions.
7. The soundproof structure according to claim 1, wherein the soundproof structure is a structure in which the inner space and the outside are connected to each other through the first opening portion so as to be able to transmit a gas propagating sound, and is a structure that causes a resonance phenomenon with respect to a sound flowing through the first opening portion.
8. The soundproof structure according to claim 7, wherein the soundproof unit causes air column resonance of an approximately closed tube with respect to sound, as the resonance phenomenon, by the inner space and the first opening portion.
9. The soundproof structure according to claim 1, wherein the outer shell of the soundproof unit is formed of the same material.
10. The soundproof structure according to claim 1, further comprising: a duct-shaped member that has a space thereinside, wherein the two or more soundproof units are disposed inside the duct-shaped member.
11. The soundproof structure according to claim 1, wherein the two or more soundproof units are disposed on a wall.
12. The soundproof structure according to claim 1, further comprising: a moving mechanism that moves the first opening portion of one of the two adjacent soundproof units relative to the first opening portion of the other soundproof unit, wherein the moving mechanism changes a distance between the first opening portions of the two adjacent soundproof units.
13. The soundproof structure according to claim 12, wherein the moving mechanism is a rail traveling mechanism comprising a rail and a wheel on which at least one of the two adjacent soundproof units is mounted and which travels on the rail.
14. The soundproof structure according to claim 12, wherein the moving mechanism is a screw moving mechanism, which comprises a ball screw and a nut to which at least one of the two adjacent soundproof units is attached and which is screwed to the ball screw, a rack to which at least one of the two adjacent soundproof units is attached and a rack and pinion mechanism with pinion engaged with the rack.
15. A soundproof system, comprising: the soundproof structure according to claim 1; a measurement unit that measures noise in a surrounding environment of the soundproof structure; and an analysis unit that analyzes a frequency of noise measured by the measurement unit, wherein a distance between the first opening portions of the two adjacent soundproof units is changed according to an analysis result of the analysis unit.
16. The soundproof system according to claim 15, wherein the soundproof mechanism is the soundproof structure according to claim 12, the moving mechanism is an automatic moving mechanism further comprising a driving source and a control unit that controls driving of the driving source, the analysis unit determines a movement amount of at least one of the two adjacent soundproof units according to the analysis result, and the control unit controls the driving of the driving source according to the determined movement amount to automatically move at least one of the two adjacent soundproof units such that a distance between the first opening portions of the two adjacent soundproof units is changed.
17. The soundproof system according to claim 16, further comprising: a plurality of the measurement units, wherein the analysis unit analyzes the frequency of noise measured by each of the plurality of measurement units, and determines the movement amount of at least one of the two adjacent soundproof units according to the analysis result.
18. The soundproof structure according to claim 1, wherein a film that vibrates with respect to sound is not attached to the first opening portion.
19. The soundproof structure according to claim 1, wherein at least one of the soundproof units is formed by only a cylindrical outer shell.
20. The soundproof structure according to claim 1, wherein the soundproof structure absorbs sound using air column resonance.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
(36) Hereinafter, a soundproof structure and a soundproof system according to the embodiment of the present invention will be described in detail with reference to preferred embodiments shown in the accompanying diagrams.
(37) The soundproof structure according to the embodiment of the present invention is characterized in that the resonance frequency is shifted to the low frequency side by arranging opening portions of soundproof units each having a cylindrical outer shell, which has a hollow inner space thereinside and comprises an opening portion opened to the outside on a surface that is one end portion, close to each other less than 20 mm, so that it is possible to insulate sounds on the low frequency side with the same volume.
(38) According to the present invention, it is possible to insulate sounds on the low frequency side (that is, selectively strongly shield low-frequency sounds) with a simple configuration, realize reductions in size and weight, and easily change the frequency characteristics.
(39) In addition, according to the present invention, it is possible to easily adjust the center frequency of soundproofing according to the external noise environment.
(40) Air column resonance is a well-known resonance phenomenon in the field of sound, and is a phenomenon in which resonance occurs in a case where the length obtained by performing opening end correction for the length of the cylinder (tube) matches the length of (wavelength/4) of the wavelength in a one side open and one side closed cylindrical structure (for example, a cylindrical structure (for example, an air column resonance tube) of a one side closed tube or a cylindrical structure in which five surfaces of a quadrangular prismatic tube having a quadrangular cross section are closed and only one surface is open). At this time, in the air column resonance tube, absorption or reflection of sound occurs due to strong resonance in the tube. In a structure using the air column resonance tube, since only a cylindrical structure is necessary, the configuration can be made very simple and strong. In such a structure, sound is absorbed by the entire tube without having a specific thin film absorption structure, a micro through-hole, or the like. Therefore, since no load is applied to only a specific thin sound absorbing portion, durability can also be increased. In addition, since there is no specific thin sound absorbing structure, the absorption frequency or the absorbance depends on the size of the entire cylinder. Therefore, there is a merit that the robustness with respect to the size is relatively large. On the other hand, as a problem at the time of use for soundproofing or muffling, since the length of the cylinder is on the order of a wavelength, the structure becomes very large especially for use for muffling on the low frequency side. (For example, in a structure using a vibration film type sound absorbing material, a Helmholtz resonance type sound absorbing body, or the like, sound absorption can be realized with a structure smaller than wavelength by using the phase change of the vibration film and the through-hole).
(41) The present invention is an invention capable of insulating sounds on the low frequency side with a compact structure by preparing the cylindrical structures of the one side closed tubes described above and bringing opening portions thereof close to each other so that the resonance frequency is shifted to the low frequency side.
(42) In the present invention, the frequency amount shifted to the low frequency side depends on the distance between two first opening portions, and shifting to the low frequency side increases as the distance decreases. Accordingly, there is also a feature that a soundproofing frequency can be adjusted simply by adjusting the distance between the two first opening portions. Therefore, by combining a distance adjusting mechanism, such as a rail, as a soundproof unit moving mechanism, it is possible to easily change the soundproofing frequency. In addition, by measuring the noise with a microphone or the like and analyzing the frequency with an analyzer or the like, appropriate sound insulation can be achieved by adjusting the distance between the two soundproof units according to the analysis result.
(43) As described above, the present invention is a new soundproof structure which is a small and lightweight low-frequency soundproof material and which can easily change the frequency characteristics.
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(45) A soundproof structure 10 according to the embodiment of the present invention shown in
(46) In the example shown in
(47) In the soundproof structure 10 of the illustrated example, the two soundproof units 12a and 12b are disposed close to each other by aligning the axis directions (for example, central axis directions) of the cylindrical shapes of the outer shells 16a and 16b so that the opening portion 14a of the outer shell 16a and the opening portion 14b of the outer shell 16b face each other.
(48) Here, between two soundproof units 12a and 12b disposed close to each other, specifically, between the opening portions (opening ends) 14a and 14b of the outer shells 16a and 16b of the two soundproof units 12a and 12b, a rectangular parallelepiped slit 20 communicating with the inner spaces 13a and 13b is formed.
(49) In the present invention, the fact that the two soundproof units 12a and 12b are close to each other means that the opening portions (hereinafter, also referred to as opening ends) 14a and 14b, which are respective one end portions of the two outer shells 16a and 16b are close to each other. That is, the fact that the two soundproof units 12a and 12b are close to each other means that the average distance between the opening portions 14a and 14b of the two outer shells 16a and 16b is as short as less than 20 mm but the two soundproof units 12a and 12b are spaced apart from each other.
(50) Incidentally, in the present invention, the distance between the opening ends of the two outer shells 16a and 16b (for example, the distance between the two opening portions 14a and 14b) refers to a distance or an interval between the two opening ends (that is, the opening portions 14a and 14b). In the present invention, therefore, it is preferable that positions of both opening end surfaces of the two opening ends 14a and 14b, that is, positions of the opening end surface of the opening end 14a and the opening end surface of the opening end 14b, are made to face each other so as to match in the axis direction by aligning or matching the axis directions (for example, central axis directions) of the cylindrical shapes of the outer shells 16a and 16b. However, the present invention is not limited thereto, and both the opening end surfaces of the two opening ends 14a and 14b may not necessarily face each other as long as the resonance frequency of the air column resonance of the two outer shells 16a and 16b can be shifted to the low frequency side by bringing the two outer shells 16a and 16b close to each other. For example, one of the two opening ends 14a and 14b may be translated (shifted in parallel) or rotated with respect to the other one as in a soundproof structure 10d shown in
(51) In this case, in a case where the two outer shells 16a and 16b face each other in a state in which there is no overlap between both the opening ends 14a and 14b, frequency shift disappears compared with the case of a single body. That is, translation and/or rotation is allowed, but it is necessary that the two outer shells 16a and 16b face each other in a state in which there is an overlap between both the opening end surfaces. The state in which there is an overlap between both the opening end surfaces means that, in a case where a projection view obtained by projecting an opening end portion of one of the soundproof units in a direction perpendicular to the opening end surface from the opening end of the one soundproof unit is shown on the opening end of the other soundproof unit, there is a portion overlapping the other opening end.
(52) In the present invention, the distance between the opening end surfaces of the two soundproof units is defined as follows.
(53) First, as shown in
(54) In the case of the soundproof structure 10d in which there is a positional shift (translation) as shown in
(55) As a result of intensive studies on sound insulation in a low frequency region that has been difficult by the inventors of the present invention, it has been found that the sound absorption frequency is shifted to the low frequency side by bringing the opening ends of the air column resonance tubes, such as cylindrical outer shells, which are not known hitherto close to each other, that is, the effect of the low frequency shift occurs in a case where the average distance between the opening ends is less than 20 mm and the effect becomes noticeable as the average distance between the opening ends decreases. Conceivably, the reason why these findings were not made is that the wavelength of sound is extremely large compared with the gap size that a distance between the opening ends. In addition, in a case where the air column resonance tube is used for sound absorption, it is common that the opening end is mainly disposed relative to the sound or at least as shown in JP3831263B, the opening end is disposed so as to face a surface through which the sound passes (such as a structure placed in a horizontal direction with respect to the wall in a duct). Since a structure that absorbs sound based on the arrangement, in which the opening ends are brought close to each other so that the opening end surface does not directly face the surface through which the sound passes, is not common, it is thought that it was not easy to imagine the findings.
(56) In contrast, the soundproof structure 10 according to the embodiment of the present invention is preferably a structure in which the inner space 13 (13a and 13b) and the outer space are connected to each other through the opening portion 14 (14a and 14b) so as to be able to transmit a gas propagating sound, and more preferably a structure that causes an air column resonance phenomenon with respect to the sound flowing through the opening portion 14 (14a and 14b).
(57) In the present invention, it is necessary to limit the average distance D between the opening ends of the two opening ends 14a and 14b shown in
(58) In the present invention, the average distance D between the opening ends 14a and 14b is preferably 15 mm or less, more preferably 10 mm or less, even more preferably 5 mm or less, and most preferably 2 mm or less.
(59) Incidentally, in the soundproof structure 10 according to the embodiment of the present invention, in a case where the average distance D between the opening ends 14a and 14b is reduced by increasing the size Ls of the frame (rectangular tube body) around each of the opening portions 14a and 14b of the two soundproof units 12a and 12b, both the absorption peak due to air column resonance of the present invention and the absorption peak due to slit Helmholtz resonance caused by the generation of frictional heat due to thermoacoustic effect in a slit portion interposed between the frames (rectangular tube bodies) can appear together.
(60) In the following description, in a case where components of the soundproof structure 10, such as the two soundproof units 12a and 12b, the inner spaces 13a and 13b, the opening portions (opening ends) 14a and 14b, the outer shells 16a and 16b, and the lid members 18a and 18b, have the same configuration and it is not necessary to distinguish therebetween, the two soundproof units 12a and 12b, the inner spaces 13a and 13b, the opening portions (opening ends) 14a and 14b, the outer shells 16a and 16b, and the lid members 18a and 18b will be collectively described without distinction as the soundproof unit 12, the inner space 13, the opening portion (opening end) 14, the outer shell 16, and the lid member 18, respectively.
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(62) As shown in
(63) The soundproof unit 12 used in the present invention causes absorption and/or reflection of sound by resonance, so-called air column resonance of a one side closed tube formed by the rectangular tube body (frame) 17, the opening portion 14, and the lid member 18 of the outer shell 16. However, the outer shell 16 is a frame structure in which one side, on which air column resonance occurs, is closed, for example, a rectangular tube body structure, and has a feature that the standing wave of sound is formed in the entire tube and the sound wave is absorbed in the entire tube. Therefore, it is preferable that the outer shell 16 is a resonance tube structure in which not only the lid member 18 but also the four side plate-shaped members 17a are closed.
(64) The soundproof unit 12 used in the present invention is not particularly limited as long as it is possible to cause absorption and/or reflection of sound by the air column resonance of the outer shell 16, and any soundproof unit may be used. That is, the soundproof unit 12 may be any soundproof unit as long as air column resonance can occur in the inner space 13 formed by the outer shell 16 having the rectangular tube body 17, the opening end 14, and the lid member 18 on the rear surface, preferably, in the inner space 13 that is a closed space.
(65) As described above, the air column resonance in the soundproof unit 12 according to the embodiment of the present invention is the simplest resonance phenomenon even though the size of the soundproof unit is increased, compared with the case of using film vibration by a general vibration film, Helmholtz resonance by a through-hole, or slit Helmholtz resonance disclosed in JP3893053B. Therefore, since the soundproof unit 12 according to the embodiment of the present invention is very strong and has high robustness, the vibration of the structure is small. In such a soundproof unit 12, the peak of the frequency of the air column resonance with respect to the change in the proximity distance between the two opening ends 14 in a case where the two soundproof units 12 are disposed close to each other to form the soundproof structure 10, that is, the shift amount of the soundproofing frequency is large, various frequencies can be reliably and easily controlled with the proximity distance described above.
(66) Therefore, in the soundproof unit 12, as a resonance phenomenon, it is preferable to cause air column resonance of an approximately closed tube with respect to sound by the inner space 13 and the opening portion 14.
(67) The method of arranging the two soundproof units 12 used in the present invention is not limited. For example, the two soundproof units 12a and 12b can be disposed close to each other by aligning the central axis directions of the cylindrical shapes of the outer shells 16a and 16b such that the opening portion 14a of the outer shell 16a and the opening portion 14b of the outer shell 16b face each other. As in a soundproof structure 80A shown in
(68) In addition, as in a soundproof structure 80B shown in
(69) As shown in
(70) As shown in
(71) The outer shell 16 has the hollow inner space 13 inside the rectangular tube body 17 formed so as to annularly surround four side surfaces with the side plate-shaped member 17a having a thickness, and forms the rectangular tube body 17 that is a one side closed structure comprising the opening portion 14, which is for opening the inner space 13 to the outside on one side, and the lid member 18 that blocks the inner space 13 from the outer space on the other side. The air column resonance phenomenon occurs in the inner space 13 of the outer shell 16. Therefore, any members may be used as the side plate-shaped member 17a of the rectangular tube body 17 and the lid member 18 of the outer shell 16 as long as the members separate the inner space 13 from the outer space. For example, a member that acoustically separates both the members from each other is preferable, and a member that completely blocks both the members or airtightly blocks both the members is more preferable. Such a member is preferably, for example, a dense member, a member having high stiffness, or a member having both high mass per unit area and high stiffness.
(72) Preferably, in the outer shell 16, it is preferable to block the inner space 13 from the outer space except for two surfaces (surfaces onto which the opening portion 14 and the lid member 18 are attached) serving as both end portions of the outer shell 16 in the axis direction of the cylindrical shape, and it is more preferable to airtightly or completely block the inner space 13 from the outer space except for the two surfaces. That is, in the rectangular tube body 17, it is preferable to block the inner space 13 from the outer space, and it is more preferable to airtightly or completely block the inner space 13 from the outer space.
(73) The outer shell 16 is a tubular structure having a square cross section in which only one side (that is, one surface on one side) is opened by the opening portion 14 and the remaining five surfaces are closed (specifically, a rectangular tubular structure having a square cross section in which one surface on the other side is closed by the lid member 18 and the four side surfaces are closed by the rectangular tube body 17 formed by the side plate-shaped members 17a). However, the present invention is not limited thereto. For example, in the outer shell 16, one or more openings, such as through-holes, may be provided in the lid member 18, between the lid member 18 and the rectangular tube body 17, and in at least one of the four side plate-shaped members 17a of the rectangular tube body 17 as long as the openings do not interfere with air column resonance.
(74) For example, as in a soundproof unit 12c shown in
(75) Alternatively, as in a soundproof unit 12d shown in
(76) Although not shown, one or more through-holes may be provided in at least one of the four side plate-shaped members 17a of the rectangular tube body 17. However, from the viewpoint of absorption of sound by the entire inner surface of the tube in air column resonance, absorption is reduced in a case where there are through-holes. In particular, it is preferable that no through-hole is provided in the four side plate-shaped members 17a of the rectangular tube body 17.
(77) As described above, openings such as through-holes provided in the four side plate-shaped members 17a of the rectangular tube body 17 and the lid member 18 and between the four side plate-shaped members 17a of the rectangular tube body 17 and the lid member 18 (for example, the openings 22 and of 23 of the soundproof units 12c and 12d shown in
(78) On the other hand, each of the openings 22 and 23 of the soundproof units 12c and 12d shown in
(79) As shown in
(80) The shape of the opening portion 14 is the cross-sectional shape or the end surface shape of the outer shell 16 (that is, the shape of the opening portion 14 is a square in the examples shown in
(81) The soundproof unit 12 (12a, 12b, 12c, and 12d) may have a porous sound absorbing body arranged in contact with the inner space 13 (13a, 13b) or the outside of the soundproof unit 12.
(82) Here, the porous sound absorbing body has a minute air gap portion formed by a material and contains air in the air gap portion, and has a function of absorbing sound since viscous friction of the air in the vicinity of the material occurs in a case where sound passes through the minute air gap portion.
(83) As the porous sound absorbing body, for example, known sound absorbing materials, such as (1) materials containing a small amount of air and foamed materials, such as foamed urethane, flexible urethane foam, wood, ceramic particle sintered material, and phenol foam, (2) gypsum board, (3) fibers, such as glass wool, rock wool, microfiber (such as thinslate manufactured by 3M), floor mat, carpet, meltblown nonwoven fabric, metal nonwoven fabric, polyester nonwoven fabric, metal wool, felt, insulation board, and glass nonwoven fabric, and nonwoven fabric materials, (4) wood cement board, and (5) nanofiber-based materials such as silica nanofiber, can be appropriately used.
(84) The shape of the outer shell 16 may have a tubular body portion whose cross-sectional shape is the same in a partial region in the central axis direction, without being limited to the case where the cross-sectional shape perpendicular to the central axis direction of the cylindrical shape is the same over the entire region in the axis direction as shown in
(85) For example, like an outer shell 16e forming each of two soundproof units 12e of a soundproof structure 10a shown in
(86) As long as the outer shell has a partially cylindrical portion like the circular tube portion 15b as shown in
(87) Alternatively, like an outer shell 16f of a soundproof unit 12f of a soundproof structure 10b shown in
(88) In the soundproof structure 10b shown in
(89) In the shape of the outer shell 16 (16a, 16b, 16c, and 16d) of the soundproof unit 12 (12a, 12b, 12c, and 12d), as shown in
(90) As in an outer shell 16g of a soundproof unit 12g of a soundproof structure 10c shown in
(91) Hereinafter, the examples shown in
(92) In the case of a regular polygon such as a square shown in
(93) In the examples shown in
(94) As shown in
(95) As the size of the outer shell 16, the length of the outer shell 16 in the central axis direction of the cylindrical shape depending on the wavelength of the standing wave of air column resonance occurring in the outer shell 16 is important. Therefore, the size of the outer shell 16 can be defined as the length Lt of the side plate-shaped member 17a that is a constituent member of the outer shell 16 interposed between the opening end 14 and the lid member 18. That is, the size of the outer shell 16 can be defined as the length Lt of the rectangular tube body 17, and can also be defined as the size of the outer shell 16 in the axis direction of the inner space 13.
(96) The size Lt of the outer shell 16, the thickness (Ls, Lc), and the size Lo of the opening portion 14 are not particularly limited, and may be set according to a soundproofing target to which the soundproof structures 10 and 10a (hereinafter, represented by the soundproof structure 10) according to the embodiment of the present invention are applied for soundproofing, for example, a copying machine, a blower, air conditioning equipment, a ventilator, a pump, a generator, a duct, industrial equipment including various kinds of manufacturing equipment capable of emitting sound such as a coating machine, a rotary machine, and a conveyor machine, transportation equipment such as an automobile, a train, and aircraft, and general household equipment such as a refrigerator, a washing machine, a dryer, a television, a copying machine, a microwave oven, a game machine, an air conditioner, a fan, a PC, a vacuum cleaner, and an air purifier.
(97) The soundproof structure 10 itself can also be used like a partition in order to shield sound from a plurality of noise sources. Also in this case, the size of the outer shell 16 can be selected from the wavelength or the frequency of the target noise.
(98) In addition, in order to prevent sound leakage due to diffraction at the absorption peak of the soundproof unit 12, it is preferable that the size Lo of the opening portion 14 of the outer shell 16 is equal to or less than the wavelength size corresponding to the absorption peak frequency.
(99) For example, the size Lo of the opening portion 14 of the outer shell 16 is preferably 0.5 mm to 200 mm, more preferably 1 mm to 100 mm, and most preferably 2 mm to 30 mm.
(100) For example, in a case where the size Lo of the opening portion 14 is 0.5 mm to 50 mm, the thickness of the outer shell 16, in particular, the thickness Ls of the side plate-shaped member 17a of the rectangular tube body 17 is preferably 0.5 mm to 20 mm, more preferably 0.7 mm to 10 mm, and most preferably 1 mm to 5 mm.
(101) In addition, in a case where the size Lo of the opening portion 14 exceeds 50 mm and 200 mm or less, the thickness of the outer shell 16, in particular, the thickness Ls of the side plate-shaped member 17a of the rectangular tube body 17 is preferably 1 mm to 100 mm, more preferably 3 mm to 50 mm, and most preferably 5 mm to 20 mm.
(102) Although the thickness Lc of the lid member 18 of the outer shell 16 is not particularly limited, it is preferable to set the thickness Lc to be the same thickness as the thickness Ls of the side plate-shaped member 17a of the rectangular tube body 17 described above.
(103) It is preferable to set the size Lt of the outer shell 16 according to the wavelength of the standing wave of air column resonance occurring in the outer shell 16. It is most preferable to set the length obtained by subtracting the opening end correction distance from the length of (/4) of the wavelength of the sound to be soundproofed since it is possible to generate the strongest air column resonance. However, the present invention is not limited thereto, and any length may be set as the size Lt of the outer shell 16 as long as the air column resonance can be caused. From the viewpoint of ease of use, the size Lt of the outer shell 16 may be 0.5 mm to 200 mm, more preferably 0.7 mm to 100 mm, and most preferably 1 mm to 50 mm.
(104) The material of the outer shell 16, for example, the side plate-shaped member 17a of the rectangular tube body 17 and the lid member 18 is not particularly limited as long as the material has a suitable strength in the case of being applied to the above soundproofing target and is resistant to the soundproof environment of the soundproofing target, and can be selected according to the soundproofing target and the soundproof environment. Examples of the material of the outer shell 16 include a metal material, a resin material, a reinforced plastic material, a rubber material, and a carbon fiber. Examples of the metal material include aluminum, titanium, magnesium, tungsten, iron, steel, chromium, chromium molybdenum, nichrome molybdenum, and alloys thereof. Examples of the resin material include acrylic resin, methyl polymethacrylate, polycarbonate, polyamideide, polyarylate, polyether imide, polyacetal, polyether ether ketone, polyphenylene sulfide, polysulfone, polyethylene terephthalate, polybutylene terephthalate, polyimide, and triacetyl cellulose. Examples of the reinforced plastic material include carbon fiber reinforced plastics (CFRP) and glass fiber reinforced plastics (GFRP). As the rubber material, silicone rubber, synthetic rubber, natural rubber, or structure obtained by adding a filler or the like can be mentioned.
(105) A plurality of materials of the outer shell 16 may be used in combination.
(106) The material of the outer shell 16 may be the same or different. That is, the material of the side plate-shaped member 17a of the rectangular tube body 17 and the material of the lid member 18 of the outer shell 16 may be the same or different.
(107) In the present invention, however, it is preferable that the outer shell 16 of the soundproof unit 12 (that is, the side plate-shaped member 17a of the rectangular tube body 17 and the lid member 18) is formed of the same material, and it is preferable that the outer shell 16 of the soundproof unit 12 (that is, the side plate-shaped member 17a of the rectangular tube body 17 and the lid member 18) is formed of a material that does not allow sound as a gas propagating sound to pass therethrough.
(108) In the present invention, in a case where the material of the rectangular tube body 17 of the outer shell 16 and the material of the lid member 18 are the same, the rectangular tube body 17 of the outer shell 16 and the lid member 18 may be integrally formed. However, from the viewpoint of manufacturability, it is preferable that the rectangular tube body 17 of the outer shell 16 and the lid member 18 are separately formed. In a case where the material of the rectangular tube body 17 of the outer shell 16 and the material of the lid member 18 are different, it is undoubtedly preferable that the rectangular tube body 17 of the outer shell 16 and the lid member 18 are separately formed.
(109) Here, in a case where the rectangular tube body 17 serving as the frame of the outer shell 16 and the lid member 18 are separately formed, it is necessary to fix the lid member 18 to the one end surface of the rectangular tube body 17.
(110) The method of fixing the lid member 18 to the rectangular tube body 17 of the outer shell 16 is not particularly limited, and any method may be used as long as the lid member 18 can be fixed to the opening end surface on one side of the rectangular tube body 17 so that the opening end surface is closed to become a node of a standing wave of the air column resonance. For example, a method using an adhesive, a method using a physical fixture, and the like can be mentioned.
(111) In the method using an adhesive, an adhesive is applied onto the surface surrounding the opening end surface on the one side of the rectangular tube body 17 and the lid member 18 is placed thereon, so that the lid member 18 is fixed to the rectangular tube body 17 with the adhesive. Examples of the adhesive include epoxy based adhesives (Araldite (registered trademark) (manufactured by Nichiban Co., Ltd.) and the like), cyanoacrylate based adhesives (Aron Alpha (registered trademark) (manufactured by Toagosei Co., Ltd.) and the like), and acrylic based adhesives. Instead of using the adhesive directly, a double-sided tape (for example, a double-sided tape manufactured by Nitto Denko Corporation) having an adhesive on its both surfaces may be used.
(112) As a method using a physical fixture, a method can be mentioned in which the lid member 18 disposed so as to cover the opening end surface on one side of the rectangular tube body 17 is interposed between the opening end surface on one side of the rectangular tube body 17 and a fixing member, such as a rod, and the fixing member is fixed to the rectangular tube body 17 by using a fixture, such as a screw.
(113) In the soundproof structures 10, 10a, 10b, and 10c of the illustrated example, the two soundproof units 12 (12a and 12b, 12c, 12d, 12e, 12f, and 12g) are the same. However, the present invention is not limited thereto, and one soundproof unit 12 and the other soundproof unit 12 may be different soundproof units.
(114) Here, the case where the two adjacent soundproof units 12 are different is a case where the shapes or structures of the two soundproof units 12 are different. For example, the case where the two adjacent soundproof units 12 are different may be a case where different two soundproof units 12 of the soundproof units 12a (or 12b), 12c, 12d, 12e, 12f, and 12g are combined, or may be a case where the outer shells 16 (16a and 16b), 16c, 16e, 16f, or 16g used as the two soundproof units 12, the rectangular tube bodies 17 and 17c, the bent tube body 17b, and the like are different, or may be a case where the two opening ends 14 (14a and 14b, 14c, 14d, or 14e) disposed so as to face each other are different.
(115) In the soundproof structures 10, 10a, 10b, and 10c of the illustrated example, the two soundproof units 12 facing each other, that is, adjacent to each other so as to face each other are provided. However, the present invention is not limited thereto. As long as the two adjacent soundproof units 12 are included, three or more soundproof units 12 may be included.
(116) For example, as in a soundproof structure 11 shown in
(117) The method of fixing the two soundproof units 12a and 12b to the wall 26 of the structure is not particularly limited, and a known method can be used. However, as shown in a soundproof structure 90 in
(118) As a method of fixing each soundproof unit to the end surface of the protrusion 92, a method can be mentioned in which a hole portion or a recessed portion, into which the end portion of the outer shell 16a and the end portion of the outer shell 16b can be inserted, is formed in the protrusion 92.
(119) In addition, as in a soundproof structure 11a shown in
(120) In addition, as in a soundproof structure 11b shown in
(121) Here, in the soundproof structures 11, 11a, and 11b shown in
(122) In the soundproof structures 11, 11a, and 11b shown in
(123) In the following description, the two soundproof units 12a and 12b of the soundproof structure 10 shown in
(124) In addition, as in a soundproof structure 30 shown in
(125) In addition, as in a soundproof structure 30a shown in
(126) Also in this case, by increasing the number of soundproof unit sets 24, it is possible to increase the peak value of the absorbance at the absorption peak frequency.
(127) In addition, as in a soundproof structure 30b shown in
(128) As in the soundproof structure 30b shown in
(129) In addition, as in a soundproof structure 30c shown in
(130) As in a soundproof structure 30d shown in
(131) In the soundproof structures 30 and 30a to 30d shown in
(132) In addition, as in a soundproof structure 30e shown in
(133) In addition, as in a soundproof structure 30f shown in
(134) In the soundproof structures 30e and 30f shown in
(135) The soundproof unit used in the present invention and the soundproof structure according to the embodiment of the present invention using the two soundproof units are basically configured as described above.
(136) A soundproof structure 60 shown in
(137) Here, the soundproof unit 12a of the soundproof structure 10 is supported by a base (not shown), and the drive screw 66, such as a ball screw, is rotatably supported on the base.
(138) In this manner, by rotating the drive screw 66 manually or automatically to move the soundproof unit 12b with respect to the soundproof unit 12a, the average distance between the opening end 14a of the soundproof unit 12a and the opening end 14b of the soundproof unit 12b can be changed. Therefore, it is possible to adjust the absorption peak frequency at which the absorbance is the peak.
(139) In a case where a moving mechanism such as the screw moving mechanism 68 is an automatic moving mechanism that moves automatically, the moving mechanism comprises a driving source, such as a motor, and a control unit for controlling the driving of the driving source, which are not shown. The control unit automatically controls the driving source according to the movement amount given to the control unit, so that it is possible to perform automatic movement by the movement amount.
(140) Here, the screw moving mechanism 68 in the example shown in
(141) That is, the moving mechanism used in the present invention may change the average distance between the two opening ends 14a and 14b by moving one of the soundproof units 12a and 12b relatively with respect to the other one.
(142) Such a moving mechanism is not particularly limited, and any moving mechanism may be used as long as at least one of the two adjacent soundproof units 12a and 12b can be moved. For example, in addition to the screw moving mechanism 68 in the illustrated example, although not shown, a rail traveling mechanism comprising a rail and a wheel on which at least one of the two adjacent soundproof units 12a and 12b is mounted and which travels on the rail, a rack to which at least one of the two adjacent soundproof units 12a and 12b is attached, a rack and pinion mechanism with pinion engaged with the rack, and a moving mechanism such as a piezoactuator using a piezoelectric element can be mentioned.
(143) The soundproof structure such as the soundproof structure 60 comprising the screw moving mechanism 68 described above can also be configured as a soundproof system that appropriately insulates sound according to noise from a noise source.
(144) A soundproof system 70 shown in
(145) The soundproof system 70 has the soundproof structure 10 comprising the two adjacent soundproof units 12a and 12b shown in
(146) Here, the mike 72 is a measurement device for measuring the sound pressure of the noise from the noise source 78 in the surrounding environment of the soundproof structure 10, and configures a measurement unit. In this case, it is preferable that the position of the mike 72 is located closer to the noise source 78 than the soundproof structure 10. However, the mike 72 can be disposed anywhere as long as noise can be measured, so that analysis can be made anywhere.
(147) The PC 74 receives sound pressure data of the noise measured by the mike 72, converts the sound pressure data into frequency characteristics, that is, frequency spectrum, and determines a soundproofing target frequency to be soundproofed or muffled. The soundproofing target frequency is not particularly limited, and is preferably a frequency of maximum sound pressure in the audible range. For example, it is preferable to determine the soundproofing target frequency on the assumption that it is desired to remove the maximum value in the frequency spectrum (that is, assuming a frequency to be shielded).
(148) Then, the PC 74 calculates an average distance (hereinafter, referred to as an interlayer distance) between the opening ends 14a and 14b corresponding to the soundproofing target frequency. Specifically, the PC 74 refers to data stored in advance in a storage unit, such as a memory, and determines the interlayer distance between the opening ends 14a and 14b corresponding to or closest to the soundproofing target frequency (that is, the absorption peak frequency is the soundproofing target frequency) from the data. Here, the PC 74 is a frequency spectrum analyzer, and configures an analysis unit. The data stored in the memory of the PC 74 is a look-up table (that is, a correspondence table (data) between interlayer distances and frequencies) showing the relationship between the interlayer distance between the opening ends 14a and 14b of the two adjacent soundproof units 12a and 12b and the absorption peak frequency.
(149) In such a correspondence table, it is preferable to measure in advance the relationship between the interlayer distance between the opening ends 14a and 14b and the absorption peak frequency and determine the interlayer distance between the opening ends 14a and 14b based on the actually measured value.
(150) The PC 74 transmits (inputs) the interlayer distance between the opening ends 14a and 14b determined in this manner to the automatic stage 76.
(151) Although not shown, the automatic stage 76 is an automatic moving mechanism comprising a moving mechanism such as the screw moving mechanism 68 shown in
(152) In this manner, the soundproof system 70 according to the embodiment of the present invention can appropriately muffle the noise of the soundproofing target frequency.
(153) Although the soundproof system 70 in the illustrated example comprises the automatic stage 76, the soundproof system 70 may comprise only a moving mechanism instead of the automatic stage 76. In that case, the moving mechanism may be manually moved according to the interlayer distance determined by the PC 74.
(154) In a case where the PC 74 does not have a correspondence table between interlayer distances and frequencies prepared in advance, feedback may be written in the automatic stage 76 while taking the sound pressure by using two mikes.
(155) A soundproof system 70a shown in
(156) The soundproof system 70a has the soundproof structure 10, two mikes (mike 1) 72a and (mike 2) 72b, the automatic stage 76, and the PC 74.
(157) Similarly to the soundproof system 70, in the soundproof system 70a, the sound pressure of noise is measured by at least one mike of the two mikes 72a and 72b, and the soundproofing target frequency is determined from the spectrum information (frequency spectrum data) of the mike by the PC 74.
(158) The two mikes 72a and 72b measure the sound pressure at the soundproofing target frequency of the noise from the noise source 78. Here, one mike, for example, the mike 72a takes noise with a larger sound pressure at the soundproofing target frequency, and the other mike, for example, the mike 72b takes noise with a smaller sound pressure at the soundproofing target frequency. Here, as shown in
(159) In the soundproof system 70a, feedback adjustment is performed by the automatic stage 76 so that the smaller sound pressure p2 is minimized with respect to the larger sound pressure p1, that is, p2/p1 is minimized.
(160) First, a sound pressure ratio abs(p2)/abs(p1) before moving the automatic stage 76 is measured using the two mikes 72a and 72b.
(161) Then, the sound pressure ratio abs(p2)/abs(p1) is measured while moving the automatic stage 76. By searching for an interlayer distance at which the sound pressure ratio abs(p2)/abs(p1) is minimized among these, it is possible to determine an appropriate interlayer distance.
(162) Finally, by matching the absorption frequency to the soundproofing target frequency by adjusting the interlayer distance with the automatic stage 76 so as to match the appropriate interlayer distance, it is possible to reduce the noise of the soundproofing target frequency most.
(163) In the illustrated example, noise with a larger sound pressure and noise with a smaller sound pressure taken by the two mikes 72a and 72b are transmitted to the PC 74, the sound pressure ratio p2/p1 is calculated, and feedback adjustment is performed by the automatic stage 76. However, the present invention is not limited thereto, and the outputs of the two mikes 72a and 72b may be directly transmitted to the direct automatic stage 76 without passing through the PC 74.
(164) Hereinafter, the physical properties or characteristics of a structural member that can be combined with a soundproof member having the soundproof structure according to the embodiment of the present invention will be described.
(165) [Flame Retardancy]
(166) In the case of using a soundproof member having the soundproof structure according to the embodiment of the present invention as a soundproof material in a building or a device, flame retardancy is required.
(167) For this reason, the outer shell (tube body (frame) and lid member) are also preferably a flame-retardant material. A metal such as aluminum, an inorganic material such as ceramic, a glass material, flame-retardant polycarbonate (for example, PCMUPY 610 (manufactured by Takiron Co., Ltd.)), and/or flame-retardant plastics such as flame-retardant acrylic (for example, Acrylite (registered trademark) FR1 (manufactured by Mitsubishi Rayon Co., Ltd.)) can be mentioned.
(168) As a method of fixing the lid member to the tube body (frame), a bonding method using a flame-retardant adhesive (Three Bond 1537 series (manufactured by Three Bond Co. Ltd.)) or solder or a mechanical fixing method, such as fixing the lid member to the tube body (frame) with a screw or the like, is preferable.
(169) [Heat Resistance]
(170) There is a concern that the soundproofing characteristics may be changed due to the expansion and contraction of the structural member of the soundproof structure according to the embodiment of the present invention due to an environmental temperature change. Therefore, the material forming the structural member is preferably a heat resistant material, particularly a material having low heat shrinkage.
(171) As the outer shell (tube body (frame) and lid member), it is preferable to use heat resistant plastics, such as polyimide resin (TECASINT 4111 (manufactured by Enzinger Japan Co., Ltd.)) and/or glass fiber reinforced resin (TECAPEEKGF 30 (manufactured by Enzinger Japan Co., Ltd.)) and/or to use a metal such as aluminum, an inorganic material such as ceramic, or a glass material.
(172) As the adhesive, it is preferable to use a heat resistant adhesive (TB 3732 (Three Bond Co., Ltd.), super heat resistant one component shrinkable RTV silicone adhesive sealing material (manufactured by Momentive Performance Materials Japan Ltd.) and/or heat resistant inorganic adhesive Aron Ceramic (registered trademark) (manufactured by Toagosei Co., Ltd.)). In the case of applying these adhesives to the lid member or the tube body (frame), it is preferable to set the thickness to 1 m or less so that the amount of expansion and contraction can be reduced.
(173) [Weather Resistance and Light Resistance]
(174) In a case where the soundproof member having the soundproof structure according to the embodiment of the present invention is disposed outdoors or in a place where light is incident, the weather resistance of the structural member becomes a problem.
(175) Therefore, as the material of the outer shell (tube body (frame) and lid member), it is preferable to use plastics having high weather resistance such as polyvinyl chloride, polymethyl methacryl (acryl), metal such as aluminum, inorganic materials such as ceramics, and/or glass materials.
(176) As an adhesive, it is preferable to use epoxy resin based adhesives and/or highly weather-resistant adhesives such as Dry Flex (manufactured by Repair Care International).
(177) Regarding moisture resistance as well, it is preferable to appropriately select an outer shell (tube body (frame) and lid member) and an adhesive having high moisture resistance. Regarding water absorption and chemical resistance, it is preferable to appropriately select an appropriate outer shell (tube body (frame) and lid member) and adhesive.
(178) The soundproof structure and the soundproof system according to the embodiment of the present invention are basically configured as described above.
(179) Since the soundproof structure and the soundproof system according to the embodiment of the present invention are configured as described above, low-frequency shielding that is difficult in the conventional soundproof structure can be realized and the frequency can be lowered. In addition, since the absorption peak frequency can be adjusted in the low frequency region, there is also a feature that it is possible to design a structure that is strongly soundproofed or insulated according to noise of various frequencies.
(180) The soundproof structure according to the embodiment of the present invention can be used as the following soundproof members.
(181) For example, as soundproof members having the soundproof structure according to the embodiment of the present invention, it is possible to mention: a soundproof member for building materials (soundproof member used as building materials); a soundproof member for air conditioning equipment (soundproof member installed in ventilation openings, air conditioning ducts, and the like to prevent external noise); a soundproof member for external opening portion (soundproof member installed in the window of a room to prevent noise from indoor or outdoor); a soundproof member for ceiling (soundproof member installed on the ceiling of a room to control the sound in the room); a soundproof member for floor (soundproof member installed on the floor to control the sound in the room); a soundproof member for internal opening portion (soundproof member installed in a portion of the inside door or sliding door to prevent noise from each room); a soundproof member for toilet (soundproof member installed in a toilet or a door (indoor and outdoor) portion to prevent noise from the toilet); a soundproof member for balcony (soundproof member installed on the balcony to prevent noise from the balcony or the adjacent balcony); an indoor sound adjusting member (soundproof member for controlling the sound of the room); a simple soundproof chamber member (soundproof member that can be easily assembled and can be easily moved); a soundproof chamber member for pet (soundproof member that surrounds a pet's room to prevent noise); amusement facilities (soundproof member installed in a game centers, a sports center, a concert hall, and a movie theater); a soundproof member for temporary enclosure for construction site (soundproof member that covers the construction site and prevents leakage of noise around the construction site); and a soundproof member for tunnel (soundproof member installed in a tunnel to prevent noise leaking to the inside and outside the tunnel).
EXAMPLES
(182) The soundproof structure according to the embodiment of the present invention will be specifically described by way of examples.
(183) First, a single soundproof unit (single cell) used in the soundproof structure according to the embodiment of the present invention was manufactured as Reference example 1.
Reference Example 1
(184) First, as Reference example 1, the soundproof unit (single cell) 12 shown in
(185) Using an acrylic plate having a thickness Ls of 2 mm as the side plate-shaped member 17a of the rectangular tube body 17 of the outer shell 16, the rectangular tube body 17 having a cylindrical structure opened at both ends was manufactured. The rectangular tube body 17 had a square shape in which the size Lt of the outer shell 16 (the length of the rectangular tube body 17), that is, the length Lt of the side plate-shaped member 17a interposed between the opening portion 14 and the lid member 18 was 30 mm and the (inner) size Lo of one side of the opening portion 14 was 10 mm. As the lid member 18, an acrylic plate having a square shape with a side length of 14 mm and a thickness Lc of 2 mm was prepared. The lid member 18 was attached to one surface of the rectangular tube body 17 having a cylindrical structure. As a method for attaching the lid member 18 to the rectangular tube body 17, a double-sided tape (manufactured by Nitto Denko Corporation) was attached to the frame portion of the end surface of the cylindrical structure of the rectangular tube body 17. In this manner, the soundproof unit (single cell) 12 having a cylindrical structure in which the size Lt of the outer shell 16 was 30 mm was manufactured.
(186) The soundproof unit 12 of the single cell was measured.
(187) The acoustic characteristics were measured by a transfer function method using four mikes in a self-made acrylic acoustic tube (tubular member 32: refer to
(188) The inner diameter of the acoustic tube (32) is 40 mm, and can be sufficiently measured up to 4000 Hz or higher. The acoustic characteristics of the soundproof unit 12 of a single cell were measured using the transfer function method. The arrangement was that the opening end 14 of the soundproof unit 12 of the single cell was parallel to the cross section of the acoustic tube (32) (the opening end 14 was perpendicular to the longitudinal direction of the acoustic tube (32)). Considering the cross section including the soundproof unit 12 of the single cell, the soundproof unit 12 of the single cell occupies only 16% of the acoustic tube (32). That is, approximately 84% of the acoustic tube (32) is an opening portion. The transmittance and the reflectivity were measured in this measurement, and the absorbance was calculated as (1-transmittance-reflectivity). The absorbance calculated in this manner is shown in
(189) The measurement results (absorption peak frequency and frequency difference from the single body) of Reference example 1 are shown in Table 1.
Example 1
(190) Next, a total of two soundproof units 12 of the single cell described above were manufactured. As in the case of the soundproof structure 10 shown in
(191) In the measurement of Example 1, the transmittance and the reflectivity were measured, and the absorbance was calculated as (1transmittance-reflectivity). The absorbance calculated in this manner is shown in
(192) The measurement results (absorption peak frequency and frequency difference from the single body) of Example 1 are shown in Table 1.
(193) Hereinafter, unless otherwise stated, measure was performed under the arrangement based on the same arrangement method as in Example 1.
Examples 2 to 6 and Comparative Example 1
(194) In the same manner as in Example 1, the acoustic characteristics were measured with the distance between the opening portions 14 as 1 mm (Example 2), 2 mm (Example 3), 3 mm (Example 4), 5 mm (Example 5), 10 mm (Example 6), and 20 mm (Comparative example 1).
(195) Including Example 1 and Reference example 1, the frequency dependencies of the absorbance and the reflectivity of the measurement results of Examples 2 to 6 and Comparative example 1 are shown in
(196) TABLE-US-00001 TABLE 1 Absorption Frequency Distance peak difference from (mm) frequency single body Example 1 0.5 1540 885 Example 2 1 1665 760 Example 3 2 1880 545 Example 4 3 2030 395 Example 5 5 2160 265 Example 6 10 2310 115 Comparative 20 2440 15 example 1 Reference Single body 2425 example 1
(197) As is apparent from
(198) As is apparent from
(199) From these results,
Reference Example 2
(200) Next, using a 3D printer, the rectangular tube body (frame) 17 having a cylindrical structure with both ends opened was created in which the thickness Ls was 3 mm, the (inner) size Lo of the opening portion 14 was 15 mm46 mm, and the size of the outer shell 16 and the length (frame thickness) Lt of the rectangular tube body 17 were 35 mm. The material was ABS resin. As the lid member 18, an acrylic plate having a rectangular shape of 21 mm52 mm and a thickness of 3 mm was prepared. The plate was fixed to one surface of the rectangular tube body 17 having a cylindrical structure, thereby forming the lid member 18. The lid member 18 was fixed to the rectangular tube body 17 with a double-sided tape so that there was no gap therebetween in the same manner as in Example 1. In this manner, the soundproof unit (single cell) 12 having a cylindrical structure larger than that of Example 1 was manufactured as Reference example 2.
(201) The soundproof unit 12 of the single cell of Reference Example 2 was measured in the same manner as in Example 1.
Example 7
(202) Next, a total of two soundproof units 12 of the single cell described above were manufactured.
(203) The acoustic characteristics were measured by a transfer function method in the same manner as in Example 1 except that a self-made acoustic tube (tubular member 32: refer to
Examples 8 to 11 and Comparative Example 1
(204) In the same manner as in Example 7, the acoustic characteristics were measured with the distance between the opening portions 14 as 2 mm (Example 8), 3 mm (Example 9), 5 mm (Example 10), and 10 mm (Example 11).
(205) In the measurement of Reference example 2 and Examples 7 to 11, the transmittance and the reflectivity were measured in the same manner as in Example 1. In addition, the absorbance was calculated as (1transmittance-reflectivity). The absorbance calculated in this manner is shown in
(206) The measurement results (absorption peak frequency and frequency difference from the single body) of Reference example 2 and Examples 7 to 11 are shown in Table 2.
(207) TABLE-US-00002 TABLE 2 Absorption Frequency Distance peak difference from (mm) frequency single body Example 7 1 958 1050 Example 8 2 1102 906 Example 9 3 1192 816 Example 10 5 1294 714 Example 11 10 1500 508 Reference Single body 2008 example 2
(208) As is apparent from
(209) Focusing on absorption, it can be seen that another absorption peak appears at 590 Hz on the low frequency side particularly in a case where the distance is 1 mm. In the present invention, it has been shown that the air column resonance peak frequency is shifted to the low frequency side by reducing the distance between the opening portions 14 of the soundproof structures 10. In the soundproof structure according to the embodiment of the present invention, the length (frame thickness) Lt of the rectangular tube body 17 is large and the area (size) of the opening portion 14 is large. Accordingly, even in a cylindrical structure, end portions (frame portions) of the opening portions 14 of the rectangular tube bodies 17 in a case where the opening portions 14 are brought close to each other form a narrow slit shape. Therefore, it is considered that friction occurs in the slit portion, that is, a Helmholtz resonance phenomenon using the slit occurs. That is, by using the cylindrical structure, it is possible to use both soundproofing with high absorbance using the air column resonance frequency and slit Helmholtz resonance soundproofing using slit friction on the lower frequency side.
(210) As described above, also in a soundproof unit having a larger cylindrical structure than that of Example 1, it could be seen that the absorption peak or the reflection peak due to the air column resonance phenomenon was shifted to the low frequency side by reducing the distance between the opening portions of the two soundproof units. In addition, since the shift amount depends on the distance, it could be seen that the soundproofing frequency control using the distance as a parameter could be easily performed.
Example 12
(211) In the soundproof structure of Example 3, a frequency change in the case of shifting two cells (soundproof units 12a and 12b shown in
(212) That is, as shown in
(213)
Comparative Example 2
(214) In the same manner as in Example 3, the opening portion 14 (14a and 14b) is a square with one side of 10 mm, in which the facing distance is 2 mm and the translational shift is 10 mm. Under these conditions, there is no overlap between the opening portions 14. Measurement of the soundproof structure was performed, and the measurement results are summarized in
(215) As is apparent from the measurement results shown in
(216) From the above-described measurement results, it became obvious that the frequency could be adjusted by using a shift in the translation direction for the proximity structure instead of the facing distance between the opening portions 14 of the two soundproof units 12.
(217) TABLE-US-00003 TABLE 3 Facing Translational Absorption Frequency distance shift peak difference from (mm) (mm) frequency single body Example 3 2 0 1880 545 Example 12 2 5 2135 290 Comparative 2 10 2425 0 Example 2 Reference Single body 2425 example 1
(218) The soundproof system according to the embodiment of the present invention was checked.
(219) The soundproof system 70 shown in
(220) As shown in
(221) In addition, by providing a feedback mechanism in the soundproof system 70, it was possible to construct an automatic muffling system without creating the correspondence table between the absorption frequency and the distance between the opening ends in advance. As a result, even in a case where the device characteristics were changed, the automatic muffling mechanism could be made to function.
(222) From the above, the effects of the soundproof structure and the soundproof system according to the embodiment of the present invention are obvious.
(223) Here, the soundproof structure according to the embodiment of the present invention is a soundproof structure using absorption by air column resonance that is more robust.
(224) In contrast, the above-described JP3893053B discloses a sound absorption method using slit type Helmholtz resonance instead of absorption using air column resonance. In order to obtain the slit type Helmholtz resonance disclosed in JP3893053B, it is necessary to increase the friction in the slit portion by increasing the slit thickness or the like. For this reason, in the invention disclosed in JP3893053B, the structure is limited.
(225) In this respect, the present invention uses absorption by air column resonance that is more robust. For this reason, compared with the slit Helmholtz that relies only on the slit portion friction for absorption as in the invention disclosed in JP3893053B, vibration of structure is less likely to affect absorption. In addition, compared with the slit Helmholtz structure in which it is necessary to increase the thickness of the side wall portion for friction, in the structure according to the embodiment of the present invention, it is not necessary to increase the thickness of the frame serving as a slit thickness as long as the side wall portion shields the sound. Therefore, the soundproof structure can be kept light.
(226) From the viewpoint of controlling the frequency by the distance between the opening ends, the frequency shift of the air column resonance of the present invention is larger than the frequency shift amount of the slit Helmholtz resonance disclosed in JP3893053B. In addition, as can be seen in
(227) Although JP3893053B discloses soundproofing according to a frequency using the slit Helmholtz phenomenon that is a friction phenomenon of an end portion slit by using the C-type channel structure, air column resonance does not appear since the channel structure is used. A resonance tube based on the concept of a cylindrical shape that causes air column resonance is used in the present invention, whereas a channel structure is used in JP3893053B. Accordingly, the present invention is structurally different.
(228) In JP3893053B, considering the friction phenomenon, it is conceivable that the friction is increased and the resonance frequency is shifted by shortening the slit width of the slit Helmholtz. However, unlike in the present invention, it is not possible to shift the resonance frequency by bringing the opening portions, which are only a part of the size of the resonance tube, close to each other using the air column resonance that is a phenomenon of absorption in the entire resonance tube.
(229) In the present invention, in the above-described Examples 7 and 8 and the like, a pattern in which slit Helmholtz resonance and air column resonance appear together is found. In the present invention, unlike the channel structure used in JP3893053B, broadband absorption in which two absorption peaks appear can be realized by forming the air column as a structure in which five surfaces of the rectangular tube body are closed.
(230) The invention disclosed in JP3831263B is a technique for controlling the wavefront by arranging a plurality of one side closed rectangular tubes up to wavelength order instead of a single resonance cell formed by a one side closed rectangular tube, and the cell structure of a duct muffler requires the size of the wavelength order. For this reason, the invention disclosed in JP3831263B does not insulate sound by controlling the resonance frequency by interaction of two cells facing each other, unlike in the present invention. In addition, since the invention disclosed in JP3831263B is an invention for controlling the wavefront by arranging a number of cells, it is not possible to extract only a pair of cells forming a pair and bring the cells close to each other so that the two cells interact with each other.
(231) In the invention disclosed in JP3831263B, it is necessary to create a wavefront at which the duct end portion becomes a soft boundary by securing the distance between air column resonance tubes. For this reason, in the invention disclosed in JP3831263B, in a case where there is an interaction between the air column resonance tubes facing each other as in the present invention, the wavefront is affected. Therefore, the invention disclosed in JP3831263B is an invention on the premise of use in a state in which the air column resonance tubes facing each other are separated from each other in a region where the interaction between the tubes is small (that is, a region where the duct is thick to some extent).
(232) In addition, making the duct thin to bring the air column resonance tubes facing each other close to each other causes a phenomenon in which wind or heat hardly passes through the duct due to friction. Therefore, in the invention disclosed in JP3831263B, the air column resonance tubes are not brought close to each other unlike in the present invention.
(233) The present invention is a method of absorption using a robust structure having a very strong air column resonance, and can be used in various fields, such as suppression of explosion sound inside the tunnel, other than duct resonance. In these fields, in particular, the problem of low frequency sound is a problem that the structure size is increased. Therefore, the shift to the low frequency and the frequency tuning of the present invention are advantageous in various fields.
(234) While the soundproof structure and the soundproof system according to the embodiment of the present invention have been described in detail with reference to various embodiments and examples, the present invention is not limited to these embodiments and examples, and various improvements or modifications may be made without departing from the scope and spirit of the present invention.
EXPLANATION OF REFERENCES
(235) 10, 10a, 10b, 10c, 10d, 10e, 11, 11a, 11b, 30, 30a, 30b, 30c, 30d, 30e, 30f, 30g, 60, 80A, 80B, 90: soundproof structure
(236) 12, 12a, 12b, 12c, 12d, 12e, 12f, 12g: soundproof unit
(237) 13, 13a, 13b, 13c, 13d: inner space
(238) 14, 14a, 14b, 14c, 14d, 14e: opening portion (first opening portion)
(239) 15a, 15d: base end portion
(240) 15b: circular tube portion
(241) 15c, 15e: distal end portion
(242) 16, 16a, 16b, 16c, 16d, 16e, 16f, 16g: outer shell
(243) 17, 17c: rectangular tube body
(244) 17a: side plate-shaped member
(245) 17b: bent tube body
(246) 18, 18a, 18b, 18c: lid member
(247) 19: connection member
(248) 20: slit
(249) 22, 23: opening (second opening portion)
(250) 24: soundproof unit set
(251) 26: wall
(252) 28: soundproof wall
(253) 28a: soundproof wall structure
(254) 32: tubular member (acoustic tube)
(255) 32a: inner wall surface
(256) 33: hole portion
(257) 62: mounting table
(258) 64: traveling nut
(259) 66: drive screw
(260) 68: screw moving mechanism
(261) 70, 70a: soundproof system
(262) 72, 72a, 72b: microphone (mike)
(263) 74: personal computer (PC)
(264) 76: automatic stage
(265) 78: noise source
(266) 82: protruding portion
(267) 84: recessed portion
(268) 86: narrow portion
(269) 88: thick portion
(270) 92: protrusion