Anti-diffraction device and sound barrier

Abstract

The utility model discloses an anti-diffraction device and a sound barrier, and relates to the technical field of sound insulation, and the anti-diffraction device comprises a housing and a sound absorption unit. The shell comprises a first side plate, a second side plate and a top plate, wherein the first side plate and the second side plate are oppositely arranged, the top plate is connected to the top of the first side plate and the top of the second side plate, and the first side plate and the second side plate are each provided with one or more through holes. The sound absorption unit is arranged in a cavity formed among the first side plate, the second side plate and the top plate; the sound absorption unit is made of a sound absorption material, a cavity is formed in the top of the sound absorption unit, the width of the cavity is reduced towards the side away from the top plate, and the overall structure of the sound absorption unit has good sound absorption performance and can reduce low-frequency noise diffraction, has a gradually-changed structure and can reduce high-frequency noise diffraction. And the sound insulation board has a good broadband characteristic, so that the sound insulation effect is improved in a wider frequency band.

Description

Technical Field

[0001] The utility model relates to the technical field of sound insulation, in particular to an anti-diffraction device and a sound barrier. Background Art

[0002] Sound barrier 10 is a sound insulation and noise reduction device. Figure 1 It is arranged between the sound source 11 and the protection area 12, and can block the sound of the sound source 11 from propagating to the protection area 12, thereby reducing the sound pressure level in the protection area 12 and reducing the impact of the sound of the sound source 11 on the protection area 12.

[0003] For example, sound barriers 10 are installed on both sides of roads, expressways, elevated composite roads, etc. to reduce the impact of noise generated by vehicles on areas outside the road.

[0004] For another example, the sound barrier 10 can be used indoors to divide a large space into several small rooms and reduce the impact of sound between the rooms.

[0005] Currently, sound barriers are often made of materials such as concrete, metal, plastic, and glass. Because sound barrier materials are relatively "hard" compared to air, they can reflect sound waves, thereby achieving a soundproofing effect. The top of the sound barrier is generally a rigid structure that may be vertical or curved toward the sound source. It primarily reduces the transmission of noise into the protected area 12 through reflection.

[0006] However, sound wave diffraction is also a major factor affecting the performance of sound barriers. Lower-frequency sound waves have weak directivity and large wavelengths, sometimes even comparable to the sound barrier itself, resulting in strong diffraction. Therefore, low-frequency sound waves will bypass the sound barrier and propagate, weakening its sound insulation performance. Generally, significantly increasing the height of the sound barrier can reduce the impact of low-frequency noise diffraction, but this will undoubtedly increase construction costs and affect the overall aesthetic performance.

[0007] Therefore, the sound insulation effect of sound barriers still needs to be improved.

[0008] The above content is only used to help understand the technical solution of this application and does not constitute an admission that the above is prior art. Utility Model Content

[0009] The purpose of the utility model is to provide an anti-diffraction device and a sound barrier to improve the sound insulation effect.

[0010] To achieve the above-mentioned purpose of the utility model, in a first aspect, the utility model proposes an anti-diffraction device, comprising:

[0011] The housing comprises a first side panel and a second side panel arranged opposite to each other, and a top panel connected to the top of the first side panel and the second side panel, wherein the first side panel and the second side panel are each provided with one or more through holes; and

[0012] a sound absorbing unit, disposed in a cavity formed between the first side panel, the second side panel, and the top panel;

[0013] The sound absorbing unit is made of sound absorbing material. A cavity is provided on the top of the sound absorbing unit. The width of the cavity decreases toward the side away from the top plate.

[0014] In a second aspect, the present invention provides an anti-diffraction device, comprising:

[0015] a housing comprising a first side panel and a second side panel arranged opposite to each other and a top panel connected to the top of the first side panel and the second side panel, wherein the housing is made of a sound-absorbing material; and

[0016] a sound absorbing unit, disposed in a cavity formed between the first side panel, the second side panel, and the top panel;

[0017] The sound absorbing unit is made of sound absorbing material. A cavity is provided on the top of the sound absorbing unit. The width of the cavity decreases toward the side away from the top plate.

[0018] In a third aspect, the present invention proposes a sound barrier comprising an anti-diffraction device as described in any one of the above items.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the anti-diffraction device of the present invention includes a housing and a sound-absorbing unit, the housing including a first side panel and a second side panel arranged opposite each other, and a top panel connected to the tops of the first and second side panels, the first and second side panels each having one or more through holes; the sound-absorbing unit is disposed in a cavity formed between the first and second side panels, and the top panel; the sound-absorbing unit is made of a sound-absorbing material. A cavity is disposed on the top of the sound-absorbing unit, the width of which decreases toward the side away from the top panel. The overall structure has both good sound absorption performance, which can reduce low-frequency noise diffraction, and a gradual structure, which can reduce high-frequency noise diffraction. It has good broadband characteristics, thereby improving the sound insulation effect within a wider frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the location of the sound barrier described in the background technology section.

[0021] Figure 2 It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention, wherein the anti-reflection device includes a rectangular sound absorbing unit.

[0022] Figure 3 This is an application of an embodiment of the present invention. Figure 2 Schematic diagram of the structure of the sound barrier of the anti-reflection device shown.

[0023] Figure 4 It is a schematic diagram of the position of the sound barrier when modeling in the present utility model.

[0024] Figure 5a This is a schematic diagram of an embodiment of the present invention in which a sound absorbing structure is provided on the top of the sound barrier.

[0025] Figure 5b It is a schematic diagram of an upright sound barrier in an embodiment of the present utility model.

[0026] Figure 6 yes Figure 5a Sound absorption coefficient curve of medium sound absorbing structure.

[0027] Figure 7a and Figure 7b yes Figure 5a and Figure 5b Difference sound field diagram of the sound barrier shown.

[0028] Figure 7c is Figure 5a The sound absorption coefficient curve shown in the figure marks the sound absorption coefficient curve of the anti-diffraction sound barrier after the reduction of the sound pressure level in the protected area compared with the upright sound barrier.

[0029] Figure 8 This is a schematic structural diagram of an anti-diffraction device according to an embodiment of the present invention, in which a through hole is provided on only one side.

[0030] Figure 9 yes Figure 2 and Figure 8 The sound absorption coefficient curve of the anti-diffraction device shown.

[0031] Figure 10 It is a three-dimensional schematic diagram of an anti-diffraction device in an embodiment of the present utility model.

[0032] Figure 11 It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention, which includes a traditional wedge-shaped sound absorbing unit.

[0033] Figure 12a It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention. The anti-diffraction device includes discrete wedge-shaped sound absorbing units, and adjacent sound absorbing panels are arranged in a close-fitting manner.

[0034] Figure 12bIt is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention. The anti-diffraction device includes discrete wedge-shaped sound absorbing units, and adjacent sound absorbing panels are arranged at intervals.

[0035] Figure 13 It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention, wherein the anti-diffraction device includes a double-plate sound absorbing unit.

[0036] Figure 14a and Figure 14b yes Figure 13 Sound pressure level field diagrams of the sound barrier and upright sound barrier shown.

[0037] Figure 15a This is a schematic diagram of modeling various sound barriers during simulation in some embodiments of the present invention.

[0038] Figure 15b It is a schematic diagram of a model when performing simulation in some embodiments of the present invention.

[0039] Figure 15c is through Figure 15b Model pair Figure 15a Diffraction energy curves obtained after energy flux integration of various sound barriers.

[0040] Figure 15d Yes Figure 15c The curve graph is obtained by enlarging the area of ​​200Hz to 800Hz.

[0041] Figures 16a to 16c yes Figure 15a The difference sound field diagram between other sound barriers and upright sound barriers.

[0042] Figure 17 It is a sound absorption coefficient curve of double-layer PET plate, rectangular glass fiber, glass fiber wedge and PET wedge type sound absorption units.

[0043] Figure 18 It is a schematic diagram of the sound wave transmitted by the sound-absorbing wedge.

[0044] Figure 19 It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention, wherein the anti-diffraction device includes an integrated sound absorbing unit provided with a cavity.

[0045] Figure 20 It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention, which includes an inverted wedge-type (without small cavity) sound absorption unit.

[0046] Figure 21 It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention, which includes an inverse wedge-type (with a small cavity) sound absorbing unit.

[0047] Figure 22a This is a structural diagram of two layers of sound-absorbing panels placed together in one embodiment of the present invention.

[0048] Figure 22b yes Figure 22a Schematic diagram of the two layers of sound-absorbing panels placed separately.

[0049] Figure 22c yes Figure 22a and Figure 22b Graph of the sound absorption coefficient for the structure shown.

[0050] Figure 23 It is a curve of sound absorption coefficient when the sound absorption unit is a wedge, an inverted wedge (with a small cavity) and an inverted wedge (without a small cavity).

[0051] Figure 24a It is a diffraction energy curve diagram of the upright sound barrier in the utility model and the sound barrier with double-plate sound absorbing unit, wedge (PET) sound absorbing unit, wedge (glass fiber) sound absorbing unit, rectangular glass fiber sound absorbing unit, inverse wedge (with small cavity) sound absorbing unit and inverse wedge (without small cavity) sound absorbing unit respectively.

[0052] Figure 24b Yes Figure 24a The curve graph is obtained by amplifying the frequency band above 200Hz.

[0053] Figure 25a and Figure 25b It is the difference sound field diagram between the sound barrier with a sound-absorbing unit of an inverted wedge structure (with a small cavity) and the upright sound barrier.

[0054] Figure 26 This is a schematic structural diagram of a sound absorbing unit according to an embodiment of the present invention. In the figure, the number of sound absorbing panels is an even number.

[0055] Figure 27a This is a structural diagram of a sound absorbing unit in an embodiment of the present invention. In the figure, the sound absorbing panel includes two sub-sound absorbing panels bonded together.

[0056] Figure 27b This is a structural diagram of a sound absorbing unit in an embodiment of the present invention. In the figure, the sound absorbing panel includes two sub-sound absorbing panels arranged at intervals.

[0057] Figure 28a It is a schematic diagram of a clamping mechanism in one embodiment of the present utility model.

[0058] Figure 28b yes Figure 29 Enlarged view of part I in the middle.

[0059] Figure 29This is a schematic structural diagram of an anti-diffraction device according to an embodiment of the present invention. In the figure, the housing includes a bottom plate.

[0060] Figure 30 This is an embodiment of the present invention. Figure 29 Schematic diagram of the structure of the sound barrier of the anti-diffraction device shown.

[0061] Figure 31 This is an embodiment of the present invention. Figure 21 Schematic diagram of the structure of the sound barrier of the anti-diffraction device shown.

[0062] Figure 32a It is a schematic structural diagram of an upright sound barrier in an embodiment of the present utility model.

[0063] Figures 32b to 32d Schematic diagrams of the structures of sound barriers with inverted wedge type (with small cavity), double-plate type and ordinary wedge type sound-absorbing units respectively.

[0064] Figure 33 It is an application Figures 32a to 32d The frequency response curve of the protected area behind the sound barrier is shown.

[0065] Figure 34a It is a structural schematic diagram of an anti-diffraction device in an embodiment of the present invention. The shell of the anti-diffraction device is made of sound-absorbing material.

[0066] Figure 34b yes Figure 34a Enlarged view of part II.

[0067] Figure 35a This is a schematic diagram of an indoor sound insulation structure according to an embodiment of the present invention. In the figure, the anti-reflection device is connected to the ceiling.

[0068] Figure 35b This is a schematic diagram of an indoor sound insulation structure of an embodiment of the present utility model. In the figure, the anti-reflection device is connected to the sound barrier.

[0069] Figure 36a This is a schematic diagram of an indoor sound insulation structure in an embodiment of the present utility model. In the figure, the anti-reflection device includes a single-layer anti-reflection plate.

[0070] Figure 36b This is a schematic diagram of an indoor sound insulation structure according to an embodiment of the present invention. In the figure, the anti-reflection device includes a double-layer anti-reflection plate.

[0071] Figure 36c This is a schematic diagram of an indoor sound insulation structure of an embodiment of the present utility model. In the figure, the anti-reflection device includes a double-layer anti-reflection plate and is connected to the sound barrier.

[0072] Figure 36d It is a schematic diagram of an anti-reflection device in an embodiment of the present invention.

[0073] Figure 37 It is a sound absorption coefficient curve diagram of the anti-reflection device with a single-layer anti-reflection plate and the anti-reflection device with a double-layer anti-reflection plate in the utility model.

[0074] Figure 38 It is an insertion loss curve diagram of the anti-reflection device of the utility model with double-layer anti-reflection plates of different lengths.

[0075] Figure 39a It is a schematic diagram of an indoor sound insulation structure of an embodiment of the present utility model.

[0076] Figure 39b This is a schematic diagram of an indoor sound insulation structure in an embodiment of the present invention. Figure 39a An anti-reflection device having a single-layer anti-reflection plate is added.

[0077] Figure 39c This is a schematic diagram of an indoor sound insulation structure in an embodiment of the present invention. Figure 39b An anti-reflection device with a double-layer anti-reflection plate has been added.

[0078] Figure 39d This is a schematic diagram of an indoor sound insulation structure in an embodiment of the present invention. Figure 39c , an anti-diffraction device is installed on the top of the sound barrier.

[0079] Figure 40 yes Figures 39a to 39d Insertion loss curve of indoor sound insulation structure shown. DETAILED DESCRIPTION

[0080] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0081] As used herein, the terms "comprise," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0082] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0083] like Figure 2 As shown, the present invention proposes an anti-diffraction device 51 , which includes a housing 2 and a sound absorbing unit 3 arranged inside the housing 2 .

[0084] The housing 2 includes a first side panel 20, a second side panel 21, and a top panel 22 connected to the tops of the first and second side panels 20, 21. The first and second side panels 20, 21 are provided with through-holes 200. A cavity 23 is formed between the first and second side panels 20, 21, and the top panel 22. The sound absorbing unit 3 is disposed within the cavity 23 and is made of a sound absorbing material (or porous material), such as fiberglass, rock wool, sponge, foam metal, PET (polyester fiber), or melamine foam.

[0085] like Figure 3 and Figure 4 As shown, when in use, the anti-diffraction device 51 is located on the top of the sound barrier 5, and the sound barrier 5 is located between the sound source 11 and the protection area 12, and is used to reduce the sound transmitted from the sound source 11 to the protection area 12. Through holes 200 are provided on the first side panel 20 and the second side panel 21, and sound can enter through the through holes 200 and be absorbed by the internal sound absorbing unit 3.

[0086] First, the anti-diffraction device 51 is internally provided with a sound-absorbing unit 3 that can come into contact with external sounds, that is, the top of the sound barrier 5 is relatively soft, which can reduce the impedance of the top. Compared with the traditional hard-top sound barrier, on the one hand, it can absorb sound at the top, and on the other hand, the smaller impedance can reduce the sudden change of impedance at the end, thereby reducing the pressure difference and particle vibration velocity on both sides of the sound barrier, thereby reducing the size of the sound diffracted from the top to the protection area 12.

[0087] In order to simulate the sound insulation effect of sound barrier 5, this paper uses Figure 4 The model shown is simulated. Figure 4 In the figure, the sound source 11 is on the left side of the sound barrier 5. During the simulation, the sound source is a point sound source. The sound source 11 is 0.5m away from the ground and 3m away from the sound barrier 5. The right side is the protection area 12.

[0088] In order to verify the effect of the sound absorption coefficient on the rear of the sound barrier 5, this paper compares the sound insulation effect of the sound barrier 5 with a sound absorption structure 5a on the top of the sound barrier 5 (hereinafter referred to as the anti-diffraction sound barrier 5) and the sound barrier 5 without a sound absorption structure on the top (hereinafter referred to as the upright sound barrier or normal sound barrier or ordinary sound barrier). Figure 5a and Figure 5b As shown in FIG, the two sound barriers 5 are of the same height, both 3 m, with the difference being that the top 0.5 m of one sound barrier 5 is a sound absorbing structure 5a, while the other is not provided with a sound absorbing structure 5a. The sound absorption coefficient and frequency of the sound absorbing structure 5a exhibit periodic fluctuations, as shown in FIG. Figure 6 As shown. Figure 6 It can be seen that the sound absorbing structure 5a has good sound absorption performance at about 200 Hz, 500 Hz and 820 Hz, and the sound absorption coefficient is less than 0.1 at about 350 Hz and 690 Hz.

[0089] The sound field distribution of the two sound barriers 5 in the protection area 12 under the same sound source is obtained by simulation, and the sound field of the upright sound barrier 5 at several frequencies (specifically 200Hz, 350Hz, 500Hz, 690Hz and 820Hz) is subtracted from the sound field of the anti-diffraction sound barrier 5 to obtain Figure 7a and Figure 7b The difference sound field diagram (also called the difference sound pressure level field diagram) shown in Figure 1 shows the sound pressure level in protected area 12, which is the difference in sound pressure (i.e., the increase in insertion loss) between the two types of sound barriers 5. A larger value indicates a greater drop in sound pressure. As can be seen from the diagram, the sound pressure level in protected area 12 is lower in the frequency bands with high sound absorption coefficients (200Hz, 500Hz, and 820Hz). In the frequency bands with low sound absorption coefficients (350Hz and 690Hz), the sound pressure level in the area protected by sound barrier 5 is almost the same as that of the upright sound barrier 5. Figure 7c In the graph, the reduction in sound pressure level of the anti-diffraction sound barrier 5 at the peaks and valleys of the sound absorption coefficient compared to the upright sound barrier 5 in the protection area 12 is marked.

[0090] This shows that the anti-diffraction effect is directly related to the sound absorption performance of the top structure of sound barrier 5. It is speculated that one possible reason for this is that the strong sound absorption structure at the top absorbs noise energy, and the diffracted energy is naturally weakened. Therefore, installing an anti-diffraction device 51 with excellent sound absorption performance at the top of sound barrier 5 will effectively reduce the sound pressure of sound waves diffracted from the top of sound barrier 5 to protected area 12, thereby improving the sound insulation effect of sound barrier 5.

[0091] In the second aspect, in the present invention, both the first side plate 20 and the second side plate 21 are provided with through holes 200, which is different from the first side plate 20 which is only provided with holes facing the sound source and the second side plate 21 which is not provided with holes facing the protection area 12 (refer to FIG. Figure 8) structure can effectively increase the sound absorption effect in the lower frequency band. Figure 9 As shown, Figure 9 Shown Figure 2 and Figure 8 The curves of the sound absorption coefficients of the two structures. In the figure, the conventional layout curve corresponds to Figure 8 The structure shown, the anti-diffraction layout curve corresponds to Figure 2 In the structures shown, both are filled with sound-absorbing materials such as glass fiber and asbestos in the outer shell 2. It can be seen from the figure that with the increase of frequency, the sound absorption coefficient of the conventional layout gradually increases from 0, but the sound absorption coefficient of the anti-diffraction layout gradually increases from 0.5. In terms of frequency band, the low-frequency sound absorption coefficient of the anti-diffraction layout is much higher than that of the conventional layout, which can further improve the sound insulation effect of the sound barrier 5.

[0092] In some embodiments, to ensure sound absorption, the perforation ratio of the first side panel 20 and the second side panel 21 is greater than or equal to 15% to ensure that sound waves can reliably enter the cavity 23. The perforation ratio can be understood as the ratio of the total area of ​​all through holes 200 in the side panel to the area enclosed by the outer contour of the side panel. The number of through holes 200 can be one or more, as long as the ratio of the total area of ​​all through holes 200 to the area enclosed by the outer contour of the side panel in which they are located is greater than or equal to 15%.

[0093] Optionally, in order to ensure the reliability of sound transmission, there are multiple through holes 200. The more evenly they are distributed on the side panels, the more conducive it is to ensure the balance of sound absorption in different areas of the anti-diffraction device, thereby improving the sound absorption effect. Therefore, the through holes 200 can be evenly distributed on the side panels. The shape of the through holes 200 is not limited, for example, it can be a circular hole (refer to Figure 10 ), square hole, triangular hole, elliptical hole, long hole (reference Figure 32b ) or special-shaped holes, etc. In some embodiments, a 10 mm hole can be punched every 20 mm.

[0094] In some embodiments, the housing 2 is made of a hard material with an impedance that is at least 100 times that of air. For example, it can be made of metal or a material with a relatively hard acoustic impedance relative to air, such as plastic. It should be noted that, unless otherwise specified, in this document, "impedance" refers to acoustic impedance. The thickness of the housing 2 can be adjusted based on the strength and rigidity of the material. Generally, a thickness of 1 to 5 mm is preferred in engineering, but is not limited thereto. A hard housing can reflect sound waves, while the through holes can guide sound waves into the sound-absorbing unit, reducing diffraction and providing excellent sound insulation for both low and medium-high frequencies. In some embodiments, the housing 2 is made of a sound-absorbing material, such as the same material as the sound-absorbing unit 3, to further enhance the anti-diffraction effect. Since the sound-absorbing material itself allows sound waves to penetrate the interior, there is no need to drill holes in the housing 2 (although drilling holes is possible). Its acoustic impedance and density can be set to be lower than those of a hard housing.

[0095] It is understood that the outer shell 2 protects the internal sound-absorbing unit 3. When the sound barrier 5 is used outdoors, the requirements for wind and rain protection are relatively high, and the outer shell 2 can be made of a hard material (of course, it can also be a sound-absorbing material). When the sound barrier 5 is used indoors, the requirements for wind and rain protection are relatively low, and it can be made of a hard material or a sound-absorbing material. To improve the overall waterproof effect, the surface of the sound-absorbing unit 3 can be sprayed with a waterproof coating. When the outer shell 2 is made of a sound-absorbing material, a waterproof coating can also be sprayed.

[0096] The structure of the sound absorbing unit 3 can be varied. The following describes several structures of the sound absorbing unit 3 as examples (Examples 1 to 7). In the present invention, the length direction, width (or thickness) direction, and height direction are indicated with reference to the directions shown in the drawings.

[0097] Example 1 - Block Type

[0098] like Figure 2 As shown, in this embodiment, the sound absorbing unit 3 is in a block shape filled in the cavity 23. The sound absorbing unit 3 is made of sound absorbing materials such as glass fiber or PET.

[0099] In some embodiments, the width of the sound absorbing unit 3 gradually increases from the top plate 22 toward the side away from the top plate 22 , such as shown in Embodiment 2 and Embodiment 3.

[0100] Example 2 - Traditional wedge type (also called integrated wedge type, ordinary wedge type)

[0101] In this embodiment, Figure 11 As shown, the sound absorbing unit 3 is an integrally formed sound absorbing wedge, the cross section of which is conical, and the top of the sound absorbing wedge faces the top plate 22 .

[0102] Example 3 - Discrete Wedge

[0103] In this embodiment, Figure 12a and Figure 12b As shown, the sound absorbing unit 3 includes a plurality of sound absorbing panels 30 arranged along the width direction of the housing 2. The heights of the plurality of sound absorbing panels 30 gradually increase from the first side panel 20 and the second side panel 21 toward the middle of the cavity 23. The closer to the middle, the greater the height of the sound absorbing panel 30. In this way, the width of the sound absorbing unit 3 increases toward the sides.

[0104] Figure 12a In the embodiment, two adjacent sound absorbing panels 30 are attached to each other. Figure 12b In the embodiment, two adjacent sound absorbing panels 30 are arranged at intervals.

[0105] Example 4 - Double Plate Type

[0106] In this embodiment, Figure 13 As shown, the sound absorbing unit 3 includes two sound absorbing panels 30 that are spaced apart from each other. The two sound absorbing panels 30 are separated by air and are made of sound absorbing material.

[0107] Optionally, the two sound absorbing panels 30 are respectively attached to the first side panel 20 and the second side panel 21 to maximize the distance between the sound absorbing panels 30. The larger the distance between the two sound absorbing panels 30, the larger the space between them, which is conducive to obtaining a good sound absorption effect at low frequencies.

[0108] Optionally, the thickness of the sound absorbing plate 30 is 3 to 36 mm, and the density of the sound absorbing plate 30 is 110 to 420 kg / m 3 The greater the density, the thinner the sound absorbing plate 30 can be, so that the acoustic impedance of the sound absorbing plate 30 is more closely matched with the acoustic impedance of air, thereby improving the sound absorption effect and the anti-diffraction effect.

[0109] For example, for ordinary boards (density of about 180 to 230 kg / m 3 For example, PET board), the thickness of the sound absorbing board 30 is preferably 6 to 24 mm; for high-density board (density of about 360 to 420 kg / m 3 , such as PET board), the thickness of the sound absorbing board 30 is preferably 3 to 8 mm; for low-density boards (density of about 110 to 180 kg / m 3 , such as PET board), the thickness of the sound absorbing board 30 is preferably 10 to 36 mm.

[0110] The sound pressure level field of the sound barrier 5 with double-plate sound absorbing units 3 and the sound pressure level field of the upright sound barrier 5 are obtained by modeling, and the sound pressure level field of the sound barrier with double-plate sound absorbing units 3 is subtracted from the sound pressure level field of the upright sound barrier 5 to obtain Figure 14a and Figure 14b The sound pressure level field diagram shown in the figure shows that the normal sound barrier is an upright sound barrier, and the anti-diffraction sound barrier is a sound barrier with double-panel sound absorbing units 3. As can be seen from the figure, the anti-diffraction sound barrier has an overall improved sound insulation effect in the low-frequency broadband range compared to the upright sound barrier 5.

[0111] In order to verify the effect of different structures of sound absorbing units 3 on the anti-diffraction effect, this section uses finite element software to model and calculate the effect of the top structure of the sound barrier 5 on the diffraction effect. Figure 15a , the structure of each model is as follows:

[0112] ① Vertical sound barrier 5, height 3.5m, thickness 0.1m.

[0113] ②Wedge-type sound barrier 5, height 3.5m, the top 0.5m is a triangular wedge, the bottom width of the triangular wedge is 0.1m, and the height is 0.5m.

[0114] The wedge materials are selected from the following two types:

[0115] Flow resistance Porosity Tortuous Factor Thermal characteristic length Viscous characteristic length Standard PET board 74031 0.967 1.018 7.58e-05 4.96e-3 Low density glass fiber 11900 0.989 1.011 3.02e-04 1.43e-04

[0116] ③ Rectangular sound absorbing material (i.e. block-type sound absorbing unit 3) sound barrier 5, height 3.5m, top 0.5m is rectangular sound absorbing material, the width of the rectangle is 0.1m, the height is 0.5m, and the material is low-density glass fiber.

[0117] ④ Double-layer plate type sound barrier 5, the material of the sound absorbing plate 30 is PET, the thickness of the sound absorbing plate 30 is 9 mm, the height is 0.5 m, the distance between the two layers of plate is about 0.08 m, and they are separated by air.

[0118] Schematic diagrams of the four models are shown in Figure 15a .

[0119] The model is modeled by finite element software. Figure 15b As shown, the black dot on the left is the sound source, the barrier is located at the lower left, and the energy flow of the blue line segment on the right is integrated to obtain the sound wave energy diffracted into the protection area.

[0120] The simulation results are as follows Figure 15c and Figure 15d As shown, Figure 15c is the result of the energy flow integration of the blue segment, Figure 15d For Figure 15c The curve graph is obtained by enlarging the area of ​​200Hz to 800Hz.

[0121] Some conclusions can be drawn from the figure:

[0122] ① The energy diffracted by the upright sound barrier 5 (blue line) is the highest;

[0123] ② The wedge type has a better anti-diffraction effect than the upright type, and the wedge made of glass fiber is more effective than the wedge made of PET. This is because the use of PET sheet to make the wedge has a higher density and higher impedance, so the effect is not good (red line). The use of low-density glass fiber to make the wedge is better than the wedge made of PET sheet (light blue line segment). Therefore, reducing the density of the sound absorbing unit 3 is conducive to improving the sound insulation effect of the sound barrier 5;

[0124] ③ The rectangular sound-absorbing material sound barrier 5 (purple) has a similar effect to the double-layer PET board (9mm), with the smallest diffraction energy.

[0125] The same effect can be seen from the sound field diagram. Figures 16a to 16c These are the difference sound field diagrams (increment of insertion loss) of the upright sound barrier and the wedge-shaped, rectangular, and double-plate sound barriers 5 at 100Hz, 200Hz, and 300Hz respectively:

[0126] Figure 17 The following is a graph of the sound absorption coefficient of the sound absorbing units in the above four structures (double-layer PET plate, rectangular glass fiber, glass fiber wedge and PET wedge). Figures 16a to 16c The three field diagrams are basically consistent with the sound absorption coefficient curve. Considering the reasons, the sound absorption coefficients of several structures are analyzed as follows:

[0127] ① Considering that the structure is installed on the top of the sound barrier 5, its installation method is consistent with the direction of sound wave propagation. Figure 18 As shown, sound waves basically propagate from left to right, so the wedge structure does not necessarily have good sound absorption performance for sound waves propagating laterally.

[0128] ②The choice of wedge material is also very important. If PET sheet is used to make the wedge, its density and flow resistance are too large, impedance mismatch occurs, and sound absorption performance is weak. Therefore, a lighter and fluffier material should be selected to make the wedge. The low-density glass fiber wedge (light blue curve) has better low-frequency sound absorption performance than the PET wedge (red curve).

[0129] ③ By designing a double-layer PET board, higher sound absorption performance at low frequencies can be achieved, and its effect is comparable to that of a 10cm thick low-density glass fiber ( Figure 17 medium blue and green curves).

[0130] ④ Structures with good sound absorption performance also have better anti-diffraction effects. The trends of the sound absorption coefficient curve and the diffraction energy curve can confirm each other.

[0131] The key to the anti-diffraction sound-absorbing structure is that the sound-absorbing material is open on both sides, without a sealed baffle. This allows sound waves to transmit from the left to the right, resulting in enhanced low-frequency sound absorption. This can be achieved by providing a housing 2 with openings on both sides, or by making the housing 2 out of sound-absorbing material.

[0132] The above analysis reveals that the low-frequency sound absorption coefficient of a double-layer PET sheet can be superior to that of a wedge structure, but its mid- and high-frequency performance is not necessarily better. To this end, the structure of the sound-absorbing unit 3 can be further improved. In some embodiments, the sound-absorbing unit 3 is configured as an inverted wedge structure, i.e., an inverted wedge-shaped (or reverse wedge-shaped, or inverted wedge-shaped) cavity 31 is provided at its top, with the width of the cavity 31 decreasing toward the side away from the top plate 22, such as the structures described in Examples 5 to 7.

[0133] The advantage of this is that the sound-absorbing unit 3 at the bottom is thicker, which can play a better sound insulation role, and the thickness of the sound-absorbing unit 3 at the top gradually decreases to form a gradient. In addition, since the sound-absorbing units 3 on both sides are clamped to form a cavity 31, the structure at the top can achieve a very good sound absorption effect. The overall structure has both good sound absorption performance, which can reduce low-frequency noise diffraction, and a gradual structure, which can reduce high-frequency noise diffraction. It has good broadband characteristics, so it can combine the advantages of the "wedge" in the middle and high frequencies and the better low-frequency performance of the "double-layer thin plate".

[0134] To improve low-frequency sound absorption, the gradient (i.e., the rate at which the height of the sound-absorbing material decreases from the sides to the center) should decrease rapidly, which will create a "double-panel" effect. To improve mid- and high-frequency sound absorption, the gradient decrease rate should be slower. The decrease rate can be designed in any way, for example, it can decrease linearly or exponentially.

[0135] Example 5

[0136] like Figure 19 As shown, in this embodiment, the sound absorbing unit 3 is in the shape of an integral block, and an inverted wedge-shaped cavity 31 is provided at the upper end thereof.

[0137] Example 6 - Inverse Wedge Type (No Small Cavity)

[0138] In this embodiment, Figure 20 As shown, the sound absorbing unit 3 includes a plurality of sound absorbing panels 30 arranged along the width direction of the shell 2. Two adjacent sound absorbing panels 30 are bonded together. The heights of the plurality of sound absorbing panels 30 gradually decrease from the first side panel 20 and the second side panel 21 toward the middle of the cavity 23, so as to form an inverse wedge-shaped cavity 31 at the top of the sound absorbing unit 3.

[0139] In order to fully utilize the cavity 23 , the two outermost sound absorbing panels 30 of the sound absorbing unit 3 are connected to the first side panel 20 and the second side panel 21 respectively.

[0140] Example 7: Inverse wedge type (with small cavity)

[0141] like Figure 21 As shown, the difference between this embodiment and embodiment 6 is that the multiple sound absorbing panels 30 of the sound absorbing unit 3 are arranged at intervals along the width direction of the shell 2, that is, the adjacent two sound absorbing panels 30 are not attached to each other, but are relatively spaced apart. There is a spacing space (i.e., a small cavity) between the adjacent two sound absorbing panels 30, which can further improve the sound absorption effect.

[0142] The sound absorbing panels 30 spaced apart have better sound absorption effect than the sound absorbing panels 30 that are bonded together. For example, in the same 90mm space, two panels with a thickness of 9mm and a surface density of 200kg / m 2 The polyester fiberboards are arranged to be combined and placed (reference Figure 22a ) and separate placement (reference Figure 22b ), its sound absorption coefficient is compared with Figure 22c As shown, from Figure 22c It can be seen that the sound absorption coefficient of the separated panels 30 is greater than that of the combined panels across most frequency ranges. This is presumably because separated panels 30 facilitate acoustic impedance adjustment. Panels 30 placed close together may exhibit excessive acoustic impedance. Introducing a gap can appropriately reduce this impedance, allowing it to more closely match the acoustic impedance of air. Furthermore, sound waves will generate multiple reflections within the gap, enhancing absorption. Therefore, the sound absorption performance of the sound absorption unit 3 corresponding to Example 7 is superior to that of the sound absorption units 3 corresponding to Examples 6 and 5. Furthermore, for the dual-panel sound absorption unit 3 of Example 4, a greater distance between the two panels 30 enhances sound absorption performance. Furthermore, in a discrete wedge structure, the sound absorption performance of two adjacent panels 30 placed at intervals is superior to that of two adjacent panels 30 placed close together.

[0143] The sound absorption coefficient curves of traditional wedge, reverse wedge design (with small cavity) and reverse wedge design (without small cavity) are as follows: Figure 23 As shown in the figure, the small cavity refers to the space between two adjacent sound absorbing panels 30. The structures without small cavities and with small cavities correspond to the structures where two adjacent sound absorbing panels are bonded and spaced apart, respectively. As can be seen from the figure, the sound absorption coefficient of the inverted wedge-shaped sound absorbing unit is significantly improved across the entire frequency band, and the sound absorption coefficient can be further increased by appropriately adding cavities.

[0144] Further comparison of the diffracted sound energy in the following cases: "upright sound barrier", "double-plate structure", "wedge (PET)", "wedge (glass fiber)", "rectangular glass fiber", "inverse wedge (with small cavity)" and "inverse wedge (without small cavity)" Figure 24a As shown, Figure 24a In the figure, the horizontal axis is frequency and the vertical axis is diffraction energy. As can be seen from the figure, at 100Hz, the diffraction energy of the double plate and rectangular glass fiber is the lowest (about 0.3), the upright type is the highest (about 0.85), and the diffraction energy of the inverse wedge (with a small cavity) (purple, about 0.45) is between the wedge (0.55-0.6) and the double plate. Zooming in on the results above 200Hz, we get Figure 24b The graph shows that the inverted wedge (with a small cavity, purple line) is slightly better than the PET wedge (green line), but still outperforms the other structures. The double-panel structure performs well at low frequencies, but exhibits fluctuations in the mid- and high-frequency range (400Hz-700Hz). Furthermore, among the inverted wedges, the structure with a small cavity (purple line) also outperforms the bonded structure without a cavity (yellow line). This is presumably due to the increased density after bonding, which reduces sound absorption at the top. In summary, the inverted wedge with a small cavity is a hybrid structure that combines the characteristics of double-panel and wedge structures. Its low-frequency performance lies somewhere between those of double-panel and wedge structures, while its mid- and high-frequency performance is nearly equivalent to that of a traditional wedge.

[0145] Figure 25a and Figure 25b The difference sound field diagram from 100Hz to 800Hz is shown between the sound barrier 5 with an inverted wedge structure (with a small cavity) and the upright sound barrier 5 to reflect the increase in insertion loss. The difference sound field diagram is obtained by subtracting the sound pressure level field of the upright sound barrier 5 from the sound pressure level field of the inverted wedge (with a small cavity) sound barrier 5. It can be seen from the figure that the inverted wedge (with a small cavity) sound barrier 5 has better sound insulation effect than the upright sound barrier 5 in the entire low-frequency band.

[0146] Optionally, the sound absorbing panel 30 has five or more layers to ensure its anti-diffraction effect. More layers provide finer variations and a higher degree of homogenization, which can increase sound absorption performance over a wider frequency band, thereby enhancing its anti-diffraction effect. Furthermore, the sound absorbing panel 30 may have seven or more layers.

[0147] Optionally, the spacing between two adjacent sound absorbing panels 30 does not exceed three times the thickness of the sound absorbing panels 30 , so that the width of the sound absorbing unit 3 is more appropriate, or when the width of the sound absorbing unit 3 is constant, there are an appropriate number of sound absorbing panels 30 .

[0148] Optionally, the spacing between two adjacent sound absorbing panels 30 is no less than 2 mm, to facilitate control of the spacing between the two sound absorbing panels 30 and to reduce acoustic impedance to a certain extent. The thickness of the sound absorbing panels 30 can be, for example, 5 to 24 mm. In some embodiments, the thickness of the sound absorbing panels 30 is the same as the spacing between two adjacent sound absorbing panels 30, for example, 9 mm panels + 9 mm spacing, 18 mm panels + 18 mm spacing, 5 mm panels + 5 mm spacing, etc.

[0149] The spacing between two adjacent sound-absorbing panels 30 is related to their density and can regulate the impedance of the structure. According to homogenization theory, the sound-absorbing panels 30 and the intervening air layer form a uniform structure in the long-wave limit (wavelength >> structure size, at least 5 times greater). Their equivalent density is the arithmetic mean of the two, and their bulk modulus is the harmonic mean of the two:

[0150] ρ s =fρ p +(1-f)ρ a , where ρ s is the equivalent density of the overall structure, ρ p is the equivalent acoustic density of the sound absorbing panel 30, ρ a is the density of air, f is the filling rate of the plate, specifically written as:

[0151] Wherein dp is the thickness of the sound absorbing plate 30, and da is the thickness of the intervening air layer.

[0152] K s is the equivalent bulk modulus of the overall structure, K p is the equivalent acoustic modulus of the sound absorbing panel 30, K a is the bulk modulus of air, and f is the filling rate of the plate.

[0153] The impedance of the structure can be written as:

[0154]

[0155] Therefore, the thickness dp of the air layer can affect the filling rate, further affect the equivalent density and equivalent modulus of the structure, and ultimately affect the equivalent impedance. The closer the equivalent impedance is to the air impedance, the higher the impedance matching degree, which is more conducive to improving the sound absorption effect, thereby improving the anti-diffraction effect and sound insulation effect.

[0156] Therefore, different spacings can be selected for different panels to make the sound absorbing unit 3 have a lower equivalent impedance and be more compatible with the air impedance. For example:

[0157] When using normal density sound absorbing panels (density of about 180-230 kg / m 3 , such as PET board), the filling rate f of the sound-absorbing board should be between 0.4 and 0.6;

[0158] When using a sound-absorbing board with a higher density, the filling rate should be reduced accordingly. For example, when the gram weight is doubled (i.e. 360-460 kg / m 3 , such as PET board), f should be between 0.1 and 0.3;

[0159] When choosing a sound-absorbing board with a lower density, the filling rate should be increased accordingly, for example, the gram weight should be reduced to 70% of the original (i.e. 126-161 kg / m 3 , such as PET board), f should be between 0.6 and 0.9.

[0160] Optionally, the ratio of the height H1 of the middle sound absorbing plate 30 of the sound absorbing unit 3 to the height H2 of the outermost sound absorbing plate 30 of the sound absorbing unit 3 is greater than or equal to 10%. It is understood that the number of the middle sound absorbing plate 30 of the sound absorbing unit 3 can be one or two or more, for example, Figure 21 In the illustrated embodiment, the number of the sound absorbing panels 30 is an odd number, and in this case, the number of the middlemost sound absorbing panel 30 is one. Figure 26 In the illustrated embodiment, the number of the sound absorbing panels 30 is an even number. In this case, there are two middle sound absorbing panels 30 with the same height.

[0161] It is understood that the sound absorbing panel 30 may include one or more sub-sound absorbing panels 300 of the same height, and the sub-sound absorbing panels 300 of the same sound absorbing panel 30 may be attached to each other or spaced apart. Figure 27a and Figure 27b As shown, each sound absorbing panel 30 includes two sub-sound absorbing panels 300 . Figure 27a In the embodiment shown, the two sub-sound absorbing panels 300 of each sound absorbing panel 30 are arranged in close contact with each other. Figure 27b In the illustrated embodiment, the two sub-sound absorbing panels 300 of each sound absorbing panel 30 are arranged at intervals, which is beneficial to further improve the sound absorption coefficient and enhance the sound insulation effect.

[0162] The method for securing the sound absorbing panel 30 to the housing 2 is not limited. In some embodiments, as shown in FIG28 , the anti-diffraction device 51 includes a snap-fit ​​mechanism 4 connected to the housing 2. The snap-fit ​​mechanism 4 includes a plurality of slots 40, into which the sound absorbing panel 30 is inserted and secured. It is understood that the snap-fit ​​mechanism 4 includes at least the slots 40 corresponding to the positions and number of the desired sound absorbing panels 30. It is also understood that when a sound absorbing panel 30 includes two or more sub-sound absorbing panels 300, the snap-fit ​​mechanism 4 includes at least the slots 40 corresponding to the positions and number of the desired sub-sound absorbing panels 300.

[0163] The clamping mechanism 4 includes a plurality of elastic clamping arms 41 , and a slot 40 is formed between two adjacent elastic clamping arms 41 . The width of the slot 40 is smaller than the thickness of the sound absorbing plate 30 , so that the sound absorbing plate 30 can be clamped by the two elastic clamping arms 41 , thereby being more firmly fixed.

[0164] Furthermore, at least two ends of the sound absorbing plate 30 in the length direction are provided with a snap-fit ​​mechanism 4 to ensure the firmness of the fixation.

[0165] Optionally, the snap-fit ​​mechanism 4 is located at the bottom of the housing 2 and connected to the bottom of the sound-absorbing panel 30. Of course, the location of the snap-fit ​​mechanism 4 is not limited thereto. For example, the snap-fit ​​mechanism 4 may be located in the middle or top of the sound-absorbing panel 30, or at two or more of the bottom, middle, and top of the sound-absorbing panel 30 to further enhance the securement of the fixation.

[0166] To fully utilize the space in cavity 23 and enhance sound absorption and diffraction prevention, the ratio of the height of the sound absorbing unit 3 to the height of the cavity 23 is no less than 90%. The top of the sound absorbing unit 3 may or may not contact the top plate 22. Alternatively, the height of the sound absorbing unit 3 is the same as the height of the cavity 23 and is in contact with the top plate 22. The height of the sound absorbing unit 3 is its maximum height dimension. If it includes multiple sound absorbing panels 30, the bottoms of the panels 30 are generally flush and located at the bottom of the cavity. Therefore, the height of the sound absorbing unit 3 is equal to the height of the tallest sound absorbing panel 30.

[0167] The height of the cavity 23 is limited by the mounting structure, specifically, by its bottom support structure.

[0168] In some embodiments, as Figure 29 and Figure 30 As shown, the housing 2 includes a bottom plate 24 connected to a first side plate 20 and a second side plate 21. The top plate 22 and the bottom plate 24 are arranged opposite each other, and a cavity 23 is formed between the first side plate 20, the second side plate 21, the top plate 22, and the bottom plate 24. In this case, the bottom plate 24 serves as the bottom support structure of the cavity 23, and the sound absorbing unit 3 is supported by the bottom plate 24. The height of the cavity 23 is the distance from the bottom plate 24 to the top plate 22. Optionally, the top plate 22 also has one or more through holes 200. In this way, sound waves passing above the top plate 22 can also enter the cavity 23 through the through holes 200 and be absorbed, thereby further enhancing the anti-diffraction effect. The perforation ratio of the top plate 22 can be selected to be greater than or equal to 15%.

[0169] In some embodiments, the housing 2 does not include a bottom plate 24, such as Figure 3 and Figure 31As shown, when the anti-diffraction device 51 is mounted on the base 50, the cavity 23 uses the base 50 of the sound barrier 5 as a bottom support structure, and the sound absorbing unit 3 is supported by the base 50. At this time, the distance from the top surface 500 of the base 50 to the top plate 22 is the height of the cavity 23.

[0170] The present utility model further proposes a sound barrier 5 , which includes the anti-diffraction device 51 mentioned above, and the anti-diffraction device 51 is arranged at the top of the sound barrier 5 .

[0171] like Figure 3 、 Figure 30 and Figure 31 As shown, the sound barrier 5 further includes a base 50, and an anti-diffraction device 51 is connected to the top of the base 50. Optionally, the anti-diffraction device 51 is fixedly connected to the base 50 through its housing 2, and the connection method is not limited, for example, it can be fixed by bolts, snap connections and / or adhesive fixation.

[0172] The base 50 can be made of ordinary cement, steel structure, wood board, composite board or other materials, which can serve as hard boundary sound insulation.

[0173] The base 50 can be of uniform or unequal width, for example, a trapezoidal structure with a smaller top and a larger bottom. The width of the top surface 500 of the base 50 can be the same as the width of the anti-diffraction device 51, slightly smaller than the anti-diffraction device 51, or larger than the width of the anti-diffraction device 51, as long as it can firmly fix the anti-diffraction device 51. Optionally, the width of the sound barrier 5 ranges from 60 to 200 mm, and the height ranges from 2 to 5 meters. The height of the anti-diffraction device 51 accounts for 10% to 40% of the total height of the sound barrier 5.

[0174] The structure of the sound absorbing unit 3 in the anti-diffraction device 51 can be referred to above. Hereinafter, several sound absorbing units 3 with different structures are selected to be assembled into a sound barrier 5, and their sound insulation effects are simulated and tested.

[0175] like Figures 32a to 32d As shown, there are 4 types of sound barriers 5 for comparative testing, one of which is a vertical sound barrier 5 (reference Figure 32a ), which only includes a base 50, which is approximately 3 meters high. The other three types of sound barriers 5 include anti-diffraction devices 51. The total height of the sound barriers 5 is approximately 3 meters, the anti-diffraction devices 51 are approximately 1 meter high, and the base 50 is approximately 2 meters high. All four types of sound barriers 5 are 0.12 meters wide.

[0176] refer to Figures 32b to 32dThe three types of sound barriers 5 equipped with anti-diffraction devices 51 have sound absorbing units 3 of an inverted wedge structure (with a small cavity), a double-plate structure, and a normal wedge structure. The sound absorbing units 3 are made of the same material: standard polyester fiber PET produced by Jiangsu Baijiali New Material Technology Co., Ltd. The material has a porosity of approximately 0.97 and a flow resistivity of 74,000 Pa·s / m. 2 , thermal characteristic length 7.6e-5m, viscous characteristic length 4.96e-4m, and tortuosity factor 1.02. Figure 32a and Figure 32b The thickness of the middle sound absorbing panels 30 is 9mm. The reverse wedge type sound absorbing unit 30 includes 7 sound absorbing panels 30. The outermost PET panel is the highest and the middle one is the lowest. The heights of the 7 sound absorbing panels 30 from left to right are approximately 1m, 0.7m, 0.5m, 0.2m, 0.5m, 0.7m, and 1m. The arrangement structure can be referred to Figure 21 .

[0177] Figure 33 The graph shows the sound pressure levels in the protected area 12 behind four types of sound barriers 5. During the measurements, all parameters except the sound barrier 5 remained constant. The graph shows that the sound pressure level behind the rigid wall (i.e., upright sound barrier 5) is the highest (square line), indicating the poorest sound insulation.

[0178] For low frequencies (<200Hz), the sound pressure level is as follows: double-panel structure < inverted wedge structure < wedge structure < hard wall. Therefore, the double-panel structure can significantly increase the sound insulation in the low-frequency range.

[0179] For mid- and high-frequency regions (200Hz to 700Hz), the sound pressure level is as follows: wedge structure < reverse wedge structure < double-panel structure < hard wall, so the wedge structure in the mid- and high-frequency regions can significantly increase the sound insulation.

[0180] Overall, the effect of the inverted wedge structure is between the two, combining the characteristics of the double-plate structure and the wedge structure, and having a wider operating frequency band.

[0181] It is understood that the sound barrier 5 can be applied in a variety of scenarios. For example, it can be used outdoors, such as on both sides of roads, highways, and elevated composite roads. Another example is that it can be used indoors as a sound insulation wall to divide a large indoor space into several smaller spaces.

[0182] The following further explains the application of the sound barrier 5 indoors. The sound barrier 5 applied indoors can also be called a sound insulation wall.

[0183] The applicant has found that building partition walls indoors (especially in large flats) to form independent small compartments often presents several problems:

[0184] 1. After the partition wall is built, its position is basically fixed and it is difficult to move;

[0185] 2. In order to meet the needs of wall sound insulation, the wall often needs to be connected to the ceiling and the ground;

[0186] 3. For fire safety, the cubicle also needs to be equipped with complete fire sprinklers and other equipment and measures, which increases complexity and cost.

[0187] Many companies renting office floors in office buildings want to build flexible workspaces to suit their needs, but when the lease expires, they need to restore the existing space. Dismantling these spaces is complex, and even more time-consuming and labor-intensive when firefighting equipment is involved.

[0188] The aforementioned issues could be addressed if lightweight, portable soundproof walls could be used to construct office spaces. For example, using movable walls to construct rooms without a ceiling would facilitate installation and removal, improve air circulation, and avoid complex firefighting measures. However, these open walls present significant sound leakage, resulting in poor sound insulation and a high risk of noise disturbance.

[0189] By using the sound barrier 5 described above to build a room, you can take advantage of its excellent sound insulation effect to reduce noise interference, and it is easy to move and disassemble, and the cost is lower.

[0190] In order to facilitate the movement of the sound barrier 5, its base 50 can be made of a suitable lightweight material. In some embodiments, the base 50 includes a keel (such as a light steel keel) and a sound-absorbing material filled in the keel. The sound-absorbing material can be, for example, rock wool, glass fiber, polyester fiber, foam metal, sponge or melamine foam or a combination of these materials, with a density of 100 to 400 kg / m 3 The base 50 also includes a gypsum board or wood board disposed on the keel surface. For example, a double layer of gypsum board or wood board can be laid on the keel surface with staggered joints. The total thickness of the gypsum board or wood board can be 6 to 12 mm to achieve good sound insulation. In other embodiments, the base 50 can be made of thick wood boards.

[0191] In order to facilitate the movement of the sound barrier 5, rollers or slide rails can be set at the bottom of the base 50. In addition, in order to facilitate the sound barrier 5 to remain in the current position after movement, a fixing device can be set.

[0192] The structure of the base 50 is not a technical focus, and those skilled in the art can use the partition wall in the existing technology as the base 50.

[0193] It can be understood that since the anti-diffraction device 51 mentioned above is provided above the base 50, the base 50 can reflect sound, and the sound can be absorbed and the diffraction at the top can be reduced by the anti-diffraction device 51. Therefore, the sound barrier 5 has good sound insulation performance. Therefore, compared with the traditional sound insulation wall with no top, the sound insulation effect can be improved. Compared with the solution of setting sound-absorbing material on the entire surface of the base 50, the cost can be significantly reduced while ensuring the sound insulation effect.

[0194] However, there are still some differences between using sound barrier 5 indoors and outdoors. Specifically, when using sound barrier 5 indoors, there is a ceiling above the sound barrier 5, which is not present in outdoor areas. The ceiling will reflect sound waves down to the other side of the wall, causing a sharp drop in sound insulation. Therefore, it is still necessary to improve the indoor sound insulation structure to further improve the sound insulation effect.

[0195] To this end, the present invention also proposes an indoor sound insulation structure, which includes a sound barrier 5 and an anti-reflection device 6 arranged above the sound barrier 5. The anti-reflection device 6 is spaced apart from the sound barrier 5 and is used to absorb sound transmitted from below to the anti-reflection device 6. At least the part of the anti-reflection device 6 facing the sound barrier 5 is made of sound-absorbing material to achieve a sound-absorbing effect, thereby reducing the sound reflected from one side of the sound barrier 5 to the other side.

[0196] It can be understood that the sound barrier 5 can be an ordinary sound barrier 5 (such as a partition wall in the prior art) or the sound barrier 5 with the anti-diffraction device 51 as described above. Since the anti-reflection device 6 is provided, even if an ordinary sound barrier 5 is used, it can achieve a better sound insulation effect. After the sound barrier 5 with the anti-diffraction device 51 is provided, the sound insulation effect can be further improved.

[0197] Since the sound barrier 5 is used indoors, the requirements for waterproofing and windproofing are relatively low. Therefore, in addition to the hard materials such as plastic or metal mentioned above, its shell 2 can also be made of sound-absorbing materials, such as PET board or glass fiber, to further improve the sound absorption effect. Figure 34a and Figure 34b , Figure 34b yes Figure 34aThe enlarged view of section II in the middle illustrates an embodiment in which the housing 2 includes a first side panel 20, a second side panel 21, a top panel 22, and a bottom panel 24, all made of sound-absorbing material. Since both the first and second side panels 20, 21 are made of sound-absorbing material, when the sound-absorbing unit 3 therein employs an inverted wedge-shaped structure, the two outermost sound-absorbing panels 30 of the sound-absorbing unit 3 can be directly utilized as the first and second side panels 20, 21, thereby saving material. The two outermost sound-absorbing panels 30 of the sound-absorbing unit 3 are spaced apart from the adjacent side panels. Of course, even when the housing 2 is made of sound-absorbing material, the side panels can be omitted as sound-absorbing panels 30. Alternatively, when omitted, the outermost sound-absorbing panels 30 of the sound-absorbing unit 3 can be aligned with the adjacent side panels. Since the housing 2 is made of sound-absorbing material and inherently possesses certain sound-absorbing and sound-transmitting properties, its side panels do not necessarily have through-holes 200, but they can be provided.

[0198] When the shell 2 is made of a sound absorbing material, it is preferred that the material is the same as that of the sound absorbing plate 30, but it can also be different. In addition, the thickness of the shell 2 can also be the same as that of the sound absorbing plate 30 or different.

[0199] Understandably, the reference Figure 34b For the inverted wedge-type sound absorbing unit 3, in order to facilitate maintaining the distance between the spaced components, spacer blocks 32 may be provided between adjacent sound absorbing panels 30 and / or between the sound absorbing panels 30 and the side panels.

[0200] Optional, reference Figure 35a The anti-reflection device 6 is connected to the ceiling via a first connecting member 61. The first connecting member 61 may be a wire, for example, to hang the anti-reflection device 6 on the ceiling. A hard structure such as bolts may also be used. Figure 35b , the anti-reflection device 6 can also be connected to the sound barrier 5 using a support member 64 so that it can move together with the sound barrier 5. Obviously, the anti-reflection device 6 can be connected using the first connecting member 61 and the support member 64 at the same time.

[0201] In some embodiments, reference Figure 36a The anti-reflection device 6 includes an anti-reflection plate 60 made of sound-absorbing material. The material of the anti-reflection plate 60 can be, for example, polyester fiber, glass fiber, rock wool, sponge, foam metal or melamine foam or other sound-absorbing materials.

[0202] In some embodiments, reference Figure 36bThe anti-reflection device 6 includes two anti-reflection plates 60 made of sound-absorbing materials. The anti-reflection plates 60 can be made of, for example, polyester fiber, glass fiber, rock wool, sponge, foam metal, or melamine foam. The two anti-reflection plates 60 are spaced apart in the height direction and connected by a second connecting member 62. The second connecting member 62 can be a soft wire or a relatively hard component, such as a bolt or a sound-absorbing material block (such as a PET block). The upper anti-reflection plate 60 can be connected to the ceiling using a first connecting member 61. Figure 36c and Figure 36d When the upper and lower anti-reflection plates 60 are connected by a hard second connecting member 62, the position between the two anti-reflection plates 60 can be maintained by the hard second connecting member 62, so that a support member 64 can be used to connect to the sound barrier 5. The type of the support member 64 is not limited, for example, it can be a rod.

[0203] Figure 37 The sound absorption coefficient curves of the anti-reflection device 6 having a single-layer anti-reflection plate 60 and the anti-reflection device 6 having two layers of anti-reflection plates 60 are shown. As can be seen from the figure, the sound absorption coefficient of the single-layer anti-reflection plate 60 will have large peak-to-valley fluctuations as the frequency changes. In the main frequency band of human voice, ranging from 100 to 1000 Hz, the severe peak-to-valley fluctuations will cause the sound insulation performance to decrease in the valley. The sound absorption coefficient of the double-layer anti-reflection plate 60 is significantly higher than that of the single-layer structure. The smooth sound absorption curve helps to achieve stable sound insulation over a wide frequency range.

[0204] In some embodiments, the anti-reflection device 6 includes three or more anti-reflection plates 60 spaced apart along the height direction to further improve the sound insulation effect. The connection structure of two adjacent anti-reflection plates 60 can be referred to above.

[0205] Optionally, when the anti-reflection device 6 includes two or more anti-reflection plates 60, the thickness of the anti-reflection plates 60 is the same, or the thickness of the anti-reflection plates 60 gradually decreases from top to bottom, that is, the thickness of the relatively lower anti-reflection plate 60 is less than the thickness of the relatively upper anti-reflection plate 60. For example, in the case of including two anti-reflection plates 60, the thickness of the lower anti-reflection plate 60 can be less than the thickness of the upper anti-reflection plate 60, so that its impedance is more closely matched with the air impedance, making it easier for sound waves to enter between the two anti-reflection plates 60. Setting the thickness of the upper anti-reflection plate 60 to be relatively larger is conducive to better absorption of sound, thereby improving the effect of preventing sound reflection. At the same time, making one of the anti-reflection plates 60 thinner can reduce the amount of material used, thereby reducing costs. In some embodiments, taking a double-layer anti-reflection plate 60 made of PET material as an example, the PET plate selected is Baijiali's standard plate (density of approximately 210kg / m 3, porosity of about 0.97, flow resistivity of 74000Pa·s / m 2 , thermal characteristic length 7.6e-5m, viscous characteristic length 4.96e-4m, tortuosity factor 1.02), the thickness of the lower anti-reflection plate 60 can be 4mm, and the thickness of the upper anti-reflection plate 60 can be 5mm.

[0206] Optionally, when the anti-reflection device 6 includes two or more anti-reflection plates 60 , the distance L1 between two adjacent anti-reflection plates 60 may be 30 to 500 mm.

[0207] The thickness of the anti-reflection plate 60 can be set according to its density. Generally, the greater the density of the anti-reflection plate 60, the smaller its thickness can be. For example, when the density of the anti-reflection plate 60 is 360-420 kg / m 3 , the thickness of the bottom plate (i.e. the bottommost anti-reflection plate 60) can be 2-3 mm, and the thickness of the top plate (i.e. the topmost anti-reflection plate 60) can be 5-6 mm; when the density of the anti-reflection plate 60 is 110-180 kg / m 3 , the thickness of the bottom plate can be 5-7 mm, and the thickness of the top plate can be 9-15 mm. When the density of the anti-reflection plate 60 is 180-230 kg / m 3 , the thickness of the bottom plate (ie, the bottommost anti-reflection plate 60) can be 3 to 6 mm, and the thickness of the top plate (ie, the topmost anti-reflection plate 60) can be 6 to 10 mm.

[0208] It can be understood that the anti-reflection device 6 mainly plays the role of sound absorption. The above structure is not the only one. It only needs to have a broadband sound absorption effect. In some embodiments, the anti-reflection device 6 includes sound-absorbing cotton, and the thickness of the sound-absorbing cotton is 50 to 500 mm.

[0209] In some embodiments, reference Figure 35a The distance L4 between the sound barrier 5 and the anti-reflection device 6 along the height direction is 30 to 100 cm, and the distance L5 between the anti-reflection device 6 and the ceiling along the height direction is 5 to 30 cm.

[0210] The ends of the anti-reflection device 6 extend beyond the width of the sound barrier 5 to provide a more comprehensive anti-reflection effect, thereby minimizing mutual interference between the two rooms separated by the sound barrier 5. Optionally, in the width direction of the sound barrier 5, the ratio of the horizontal distance L2 between the ends of the anti-reflection device 6 and the sound barrier 5 is 0.8 to 1.2, so that both sides of the sound barrier 5 have a relatively consistent sound insulation effect. Further, in the width direction of the sound barrier 5, the distance L2 between the ends of the anti-reflection device 6 and the sound barrier 5 is the same, that is, the ratio is 1.

[0211] It can be understood that the length L3 of the anti-reflection device 6 determines the distance L2 of its two ends extending out of the sound barrier 5, which will affect the overall sound insulation effect. In order to verify the influence of the length L3 of the anti-diffraction device 6 on the sound insulation effect, simulation tests were carried out in four situations. In the first situation, no sound barrier 5 and anti-reflection device 6 were set up indoors; in the second to fourth situations, the same sound barrier 5 was set up indoors, and an anti-reflection device 6 with a double-layer anti-reflection plate 60 was hung under the ceiling. The difference is that the length of the anti-reflection device 6 is 0.6m, 1.2m and 2.4m respectively. In the four situations, the sound pressure level curve graph of the sound transmitted from the sound source to the same position was obtained by simulation, and then the sound pressure level curve graph in the second to fourth situations was subtracted from the sound pressure level curve graph in the first situation to obtain the insertion loss curve graph, as shown in FIG. Figure 38 As shown, Figure 38 A graph shows the insertion loss when an anti-reflection device 6 with a double-layer anti-reflection plate 60 of varying lengths L3 is suspended below the ceiling. As can be seen from the graph, the longer the anti-reflection plate 60, the better the sound insulation. To ensure the anti-reflection effect of the anti-reflection device 6, the length L3 of the anti-reflection device 6 is no less than 0.3m. Furthermore, the length L3 of the anti-reflection device 6 is optionally no greater than 3.6m to minimize obstruction of the ceiling. Alternatively, the length L3 of the anti-reflection plate 60 is 2.4m.

[0212] In order to verify the sound insulation effect of the anti-reflection device 6 and the sound barrier 5 with the anti-diffraction device 51, five different situations were simulated and tested in a room at a height of 3.5m. The five different situations are as follows:

[0213] Case 1: If Figure 39a As shown, the sound barrier 5 includes a base 50 that is 3 meters high and 10 centimeters thick, does not include an anti-diffraction device 51, and is not provided with an anti-reflection device 6. There is a gap of 0.5 meters between the sound barrier 5 and the ceiling.

[0214] Case 2: If Figure 39b As shown, the sound barrier 5 includes a base 50 that is 3m high and 10cm thick, does not include an anti-diffraction device 51, and an anti-reflection device 6 with a single-layer anti-reflection plate 60 is suspended by a wire under the ceiling. The length of the anti-reflection plate 60 is 2.4m, and the distance L2 between its two ends and the sound barrier 5 is the same, and the thickness is 0.9cm.

[0215] Case 3: If Figure 39cAs shown, the sound barrier 5 includes a base 50 that is 3m high and 10cm thick, does not include an anti-diffraction device 51, and an anti-reflection device 6 with a double layer of anti-reflection plates 60 is suspended by a line under the ceiling. The two layers of anti-reflection plates 60 are arranged in parallel and spaced apart, and their lengths are both 2.4m. The distance L2 between both ends and the sound barrier 5 is the same. The upper anti-reflection plate 60 is 0.15m away from the ceiling and has a thickness of 0.8cm. The thickness of the lower anti-reflection plate 60 is 0.4cm. The distance L1 between two adjacent anti-reflection plates 60 along the height direction is 15cm.

[0216] Case 4: If Figure 39d As shown, the sound barrier 5 comprises a 2m high, 10cm thick base 50, a 1m high, 10cm thick anti-diffraction device 51, and an anti-reflection device 6 consisting of a double layer of anti-reflection panels 60 suspended from the ceiling. The structure and position of the anti-reflection device 6 are identical to those in Case 3. The outer shell 2 of the anti-diffraction device 51 is made of a hard material and has a perforated structure. The sound absorption unit 3 inside adopts an inverted wedge-shaped (with a small cavity) structure. The sound absorption unit 3 comprises seven layers of sound absorption panels 30. The heights of the seven panels from left to right are: 1m, 0.7m, 0.5m, 0.2m, 0.5m, 0.7m, and 1m. The thickness of the sound absorption panels 30 is 0.9cm, and the spacing between panels is 0.62cm.

[0217] Case 5: No sound barrier 5 and anti-diffraction device 51 are provided.

[0218] In the above-mentioned cases, the anti-reflection plate 60, the housing 2 and the sound-absorbing plate 30 are all made of Baijiali's standard PET plate.

[0219] Figure 40 The insertion loss curves are shown in four cases. The insertion loss curves are obtained by measuring the sound pressure level curves of the sound source received at the same position in the five cases 1 to 5, and then subtracting the sound pressure level curve of case 5 from the sound pressure level curves of case 1 to 4 to obtain Figure 40 From the four insertion loss curves in the figure, it can be seen that due to the reflection of the ceiling, the sound insulation performance of the wall alone is not good as a whole, only 5 to 10 dB, with an average of about 7 dB.

[0220] Adding an anti-reflection device 6 above the sound barrier 5 can significantly increase the overall sound insulation. The sound insulation performance of the single-layer anti-reflection plate 60 can be seen to have a significant trend of changing with frequency. The insertion loss can reach 20dB at around 300Hz, and then gradually decreases. It drops to 10dB at around 700Hz and then gradually increases again.

[0221] The insertion loss of the double-layer anti-reflection plate 60 is obviously higher than that of the single-layer anti-reflection plate 60 as a whole, and is more stable, being above 20 dB as a whole.

[0222] On the basis of the double-layer anti-reflection plate 60, a sound barrier 5 with an anti-diffraction device 51 is used instead. As can be seen from the figure, the overall insertion loss can be increased by 3 to 5 dB, indicating the effectiveness of the anti-diffraction device 51.

[0223] This indoor soundproofing structure maximizes sound insulation performance without capping the walls, ensuring comfort and privacy for office workers. Because the sound barrier doesn't need to be connected to the ceiling, it's easier to move and install. It also eliminates the need for comprehensive fire sprinkler systems and other equipment in small cubicles, reducing costs.

[0224] The above is only a specific implementation of the present invention, and any improvements made based on the concept of the present invention are considered to be within the scope of protection of the present invention.

Claims

1. An anti-diffraction device, characterized in that: include: A housing (2) comprising a first side panel (20) and a second side panel (21) arranged opposite to each other, and a top panel (22) connected to the tops of the first side panel (20) and the second side panel (21), wherein the first side panel (20) and the second side panel (21) are each provided with one or more through holes (200); and a sound absorbing unit (3) disposed in a cavity (23) formed between the first side panel (20), the second side panel (21), and the top panel (22); The sound absorbing unit (3) is made of a sound absorbing material. A cavity (31) is provided on the top of the sound absorbing unit (3). The width of the cavity (31) decreases towards the side away from the top plate (22).

2. The anti-diffraction device according to claim 1, wherein: The sound absorbing unit (3) is integrated.

3. The anti-diffraction device according to claim 1, wherein: The sound absorbing unit (3) comprises a plurality of sound absorbing panels (30) arranged along the width direction of the housing (2), and the heights of the plurality of sound absorbing panels (30) gradually decrease from the first side panel (20) and the second side panel (21) toward the middle of the cavity (23).

4. The anti-diffraction device according to claim 3, wherein: Two adjacent sound absorbing panels (30) are arranged at intervals.

5. The anti-diffraction device according to claim 4, wherein: The spacing distance between two adjacent sound absorbing panels (30) does not exceed 3 times the thickness of the sound absorbing panels (30).

6. The anti-diffraction device according to claim 5, wherein: The distance between two adjacent sound absorbing panels (30) is not less than 2 mm.

7. The anti-diffraction device according to claim 3, wherein: The two outermost sound absorbing panels (30) are respectively attached to the first side panel (20) and the second side panel (21).

8. The anti-diffraction device according to claim 3, wherein: Two adjacent sound absorbing panels (30) are bonded to each other.

9. The anti-diffraction device according to claim 3, wherein: The ratio of the height of the sound absorbing plate (30) in the middle of the sound absorbing unit (3) to the height of the sound absorbing plate (30) on the outermost side of the sound absorbing unit (3) is greater than or equal to 10%.

10. The anti-diffraction device according to claim 3, wherein: It also includes a snap-fit ​​mechanism (4) connected to the housing (2), the snap-fit ​​mechanism (4) including a plurality of slots (40), the sound absorbing plate (30) being disposed in the slots (40) and fixed via the slots (40).

11. The anti-diffraction device according to claim 3, wherein: The density of the sound absorbing plate (30) is 180-230 kg / m 3 , the filling rate f of the sound absorbing plate (30) is 0.4 to 0.6; The density of the sound absorbing plate (30) is 360-460 kg / m 3 , the filling rate f of the sound absorbing plate (30) is 0.1 to 0.3; The density of the sound absorbing plate (30) is 126-161 kg / m 3 The filling rate f of the sound absorbing plate (30) should be between 0.6 and 0.

9.

12. The anti-diffraction device according to any one of claims 1 to 11, characterized in that: The sound absorbing material is glass fiber, rock wool, foam metal, PET board, sponge or melamine foam.

13. The anti-diffraction device according to any one of claims 1 to 11, characterized in that: The perforation rate of the first side plate (20) and the second side plate (21) is greater than or equal to 15%.

14. The anti-diffraction device according to any one of claims 1 to 11, characterized in that: The top plate (22) seals the top of the housing (2); or, The top plate (22) is provided with a plurality of through holes (200).

15. The anti-diffraction device according to any one of claims 1 to 11, characterized in that: The housing (2) comprises a bottom plate (24) connected to the first side plate (20) and the second side plate (21), the top plate (22) and the bottom plate (24) are arranged opposite to each other, and the cavity (23) is formed between the first side plate (20), the second side plate (21), the top plate (22) and the bottom plate (24); or, The anti-diffraction device is used to be installed on the top of the base (50) of the sound barrier, and the cavity (23) is formed between the first side panel (20), the second side panel (21), the top panel (22) and the top surface (500) of the base (50).

16. The anti-diffraction device according to any one of claims 1 to 11, characterized in that: The height of the sound absorbing unit (3) accounts for no less than 90% of the height of the cavity (23); The top of the sound absorbing unit (3) is in contact with the top plate (22) or is spaced apart from the top plate (22).

17. The anti-diffraction device according to any one of claims 1 to 11, characterized in that: The shell (2) is made of sound-absorbing material or hard material.

18. An anti-diffraction device, characterized in that: include: A housing (2) comprising a first side panel (20) and a second side panel (21) arranged opposite to each other and a top panel (22) connected to the top of the first side panel (20) and the second side panel (21), wherein the housing (2) is made of a sound-absorbing material; and a sound absorbing unit (3) disposed in a cavity (23) formed between the first side panel (20), the second side panel (21), and the top panel (22); The sound absorbing unit (3) is made of a sound absorbing material. A cavity (31) is provided on the top of the sound absorbing unit (3). The width of the cavity (31) decreases towards the side away from the top plate (22).

19. A sound barrier, characterized in that: The invention comprises an anti-diffraction device (51) as claimed in any one of claims 1 to 18.

20. The sound barrier according to claim 19, wherein: It also includes a base (50), and the anti-diffraction device is arranged on the top of the base (50); The sound barrier is used outdoors; or The sound barrier is used indoors, and the anti-diffraction device (51) is spaced apart from the ceiling.

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