A sound insulation structure

Abstract

The application discloses a sound insulation structure, which comprises a frame and a plurality of sound insulation units. The frame is provided with a plurality of mounting holes, and the sound insulation units are arranged in the mounting holes and connected with the frame. The frame is made of viscoelastic porous material, and the viscoelastic porous material is an open-pore porous material. In the application, the frame connecting the plurality of sound insulation units is made of viscoelastic porous material, so that weak connections are formed between the sound insulation units. The sound wave propagating in the frame will be attenuated, thereby greatly weakening the vibration of the frame. Meanwhile, the frame is made of viscoelastic porous material, and the possibility of exciting resonance is extremely low. Therefore, as long as the low-frequency sound insulation effect of each sound insulation unit is ensured, the sound insulation effect of the whole sound insulation structure can be ensured, the sound insulation performance is reliably ensured, and the density of the frame itself is small, so that the light weight characteristic of the sound insulation structure can be maintained.

Description

Technical Field

[0001] This invention relates to the field of sound insulation technology, and more particularly to a sound insulation structure. Background Technology

[0002] Currently, due to the development of acoustic metamaterials, lightweight sound insulation units are constantly emerging. A typical example is the thin-film sound insulation metamaterial (thin-film sound insulation unit), which consists of a supporting substrate with a honeycomb structure (such as honeycomb aluminum or honeycomb cardboard) and a thin film applied to the surface of the supporting substrate. The film is attached to the surface of the honeycomb substrate, sealing the pores of the honeycomb and having pre-stress (tension). Below the first resonant frequency of the film, the film can achieve good low-frequency broadband sound insulation due to its function.

[0003] However, this structure faces many problems in practical engineering applications:

[0004] 1. In theory, this structure assumes that the supporting substrate is fixed, which is why it has a good sound insulation effect.

[0005] In reality, the supporting substrate cannot be completely fixed in place. The vibration of the supporting substrate is directly related to its size and rigidity. When resonance occurs, the violent vibration of the supporting substrate will cause a significant decrease in sound insulation, thus losing its sound insulation effect.

[0006] The vibration law of the supporting substrate satisfies: the size of the supporting substrate / wavelength = an integer multiple. That is to say... When this happens, resonance occurs, where L is the size of the supporting substrate, λ is the wavelength of the sound wave in the supporting substrate, and n is a positive integer. The wavelength of the sound wave is directly related to the frequency, and after conversion, we can obtain the result when... Resonance will occur, where f is the frequency and c is the velocity of the sound wave in the supporting substrate.

[0007] The above formula uses a one-dimensional assumption. When we use a thin-film sound-insulating metamaterial structure to fabricate a large sound-insulating material, the material expands into a two-dimensional plane, and the resonant frequency becomes: Where nx and ny are positive integers, and Lx and Ly are the dimensions of the frame. Firstly, complete sound insulation materials are generally large in size, meaning the frame dimensions Lx or Ly will be large. This raises two issues:

[0008] ① First-order resonant frequency f 01 Or f 10 The low frequency indicates that the supporting substrate resonates severely at very low frequencies, causing the sound insulation to fail.

[0009] ② Two-dimensional materials have a large number of resonant modes and corresponding resonant frequencies. When the values ​​of nx and ny increase from 1, f will appear. 01 f 10f 11 f 20 f 02 f 12 ...a series of high-order resonances. The dense occurrence of resonances will disrupt the overall broadband effect of sound insulation, resulting in poor overall sound insulation performance.

[0010] 2. Therefore, current thin-film sound insulation materials (a membrane with tension applied to the surface of a honeycomb aluminum panel) exhibit excellent sound insulation performance in small-sample tests (single unit test, unit size ~100mm), demonstrating high sound insulation from 50Hz to 1kHz, and the overall material is very lightweight. However, once the sample size increases, or multiple units are connected to each other into a whole (units are directly fixed to each other, such as by welding or gluing), the effect decreases rapidly.

[0011] 3. To address the resonance issue, a common approach is to reinforce the supporting substrate. Reinforcing the substrate increases its overall rigidity, effectively increasing the sound wave frequency (c) within the substrate and consequently raising the resonant frequency (f). This results in better sound insulation below the resonant frequency (f). Furthermore, the location of the reinforcement alters the resonance mode, eliminating some resonant modes and reducing the impact of resonance.

[0012] However, reinforcing the supporting base to increase rigidity has several side effects: First, the reinforcing bars need to be of a certain thickness to achieve good results; second, generally speaking, the strength of the reinforcing bars is also related to the weight of the material, and reinforcing with materials such as steel is the most effective, but this is completely contrary to the purpose of lightweight sound insulation. This leads to a significant increase in the volume and weight of the frame.

[0013] Therefore, it is necessary to improve the existing technology to overcome the aforementioned defects.

[0014] 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. Summary of the Invention

[0015] The purpose of this invention is to provide a sound insulation structure to improve the sound insulation effect.

[0016] To achieve the above-mentioned objective, the present invention proposes a sound insulation structure, comprising:

[0017] Multiple soundproof units; and,

[0018] The frame has multiple mounting holes, and the sound insulation unit is disposed in the mounting holes and connected to the frame. The frame is made of viscoelastic porous material, and the viscoelastic porous material is an open-pore porous material.

[0019] Further, the viscoelastic porous material is polyester fiber, glass fiber, rock wool, foamed rubber or foamed polyester.

[0020] Further, the mounting holes and the sound insulation units are distributed in a rectangular array, and the midlines of the solid parts between adjacent mounting holes enclose a lattice. The ratio of the area S1 of the solid part of the lattice to the area S2 enclosed by the outer contour of the lattice is 2% - 30%.

[0021] Further, the flow resistivity of the porous material is 5000 < Rf < 400000, and the density is 50 kg / m 3 ~600 kg / m 3 .

[0022] Further, the outer periphery of the sound insulation unit is adhesively connected to the frame to eliminate gaps.

[0023] Further, a clamping groove is provided on the outer periphery of the sound insulation unit, and the frame is clamped in the clamping groove.

[0024] Further, the sound insulation structure includes two fixing plates respectively connected to the two surfaces of the frame. The fixing plates are provided with through holes corresponding to the mounting holes, and the size of the through holes is smaller than the size of the mounting holes. The fixing plates cover the outer edge of the sound insulation unit.

[0025] Further, the sound insulation unit is a thin - film type sound insulation unit, which includes a supporting substrate with a honeycomb structure and a thin film provided on the surface of the supporting substrate. The thin film seals the holes of the honeycomb structure.

[0026] Further, the size of the sound insulation unit is 5 mm - 500 mm.

[0027] Further, the sound insulation unit is a resonance sound insulation structure, and its resonance frequency is 40 Hz - 500 Hz.

[0028] Further, the resonance sound insulation structure is a Helmholtz resonator, which includes a flat - shaped shell. The shell is provided with an inner cavity and an opening communicating the inner cavity and the outside.

[0029] Further, the resonance sound insulation structure is a side - branch pipe structure, which includes a flat - shaped shell. The shell includes two oppositely arranged plate bodies and a side frame connected between the two plate bodies. The side frame is in a semi - enclosed shape, and one side of the shell is directly communicated with the outside.

[0030] Further, the shell includes a plurality of support columns connected between the two plate bodies, and the side frame includes three connected side plates, and two adjacent side plates are perpendicular to each other.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] According to at least one embodiment of the present invention, the sound insulation structure includes a frame and multiple sound insulation units. The frame has multiple mounting holes, and the sound insulation units are disposed within the mounting holes and connected to the frame. The frame is made of a viscoelastic porous material. In this invention, the frame connecting the multiple sound insulation units is made of a viscoelastic porous material, which creates a weak connection between the sound insulation units. Sound waves attenuate as they propagate within the frame, significantly reducing the vibration of the frame. Furthermore, the frame, being made of a viscoelastic porous material, has a very low probability of being excited into resonance. Therefore, as long as the low-frequency sound insulation effect of each sound insulation unit is ensured, the overall sound insulation effect of the sound insulation structure can be guaranteed, reliably ensuring sound insulation performance. Moreover, the frame itself has a low density, maintaining the lightweight characteristics of the sound insulation structure. Attached Figure Description

[0033] Figure 1 This is a three-dimensional schematic diagram of the sound insulation structure in some embodiments of the present invention.

[0034] Figure 2 yes Figure 1 A plan view of the middle frame.

[0035] Figure 3 This is a schematic diagram showing the lattice position of the lightweight sound insulation unit in this invention.

[0036] Figure 4 This is a comparison chart of the sound insulation curves of the sound insulation structure under three different conditions in this invention.

[0037] Figure 5 This is a schematic diagram of the sound insulation structure in some embodiments of the present invention. In the diagram, the frame is inserted into the sound insulation unit.

[0038] Figure 6 This is a three-dimensional schematic diagram of a sound insulation unit with a slot in some embodiments of the present invention.

[0039] Figure 7 This is a cross-sectional schematic diagram of the frame being inserted into the sound insulation unit in some embodiments of the present invention.

[0040] Figure 8 This is a schematic diagram of the sound insulation structure in some embodiments of the present invention. In the diagram, the sound insulation unit is installed between the frame and two fixed plates.

[0041] Figure 9 This is a cross-sectional schematic diagram of the sound insulation unit in some embodiments of the present invention, which is limited by a frame and a fixing plate.

[0042] Figure 10 yes Figure 8 A three-dimensional schematic diagram of the middle frame.

[0043] Figure 11 This is a schematic diagram of a sound insulation structure with multiple sound insulation units in some embodiments of the present invention.

[0044] Figure 12 This is a schematic diagram of a sound insulation structure with multiple sound insulation units in some embodiments of the present invention.

[0045] Figure 13 This is a three-dimensional schematic diagram of a thin-film sound insulation unit according to some embodiments of the present invention.

[0046] Figure 14 yes Figure 13 The exploded view of the thin-film sound insulation unit is shown.

[0047] Figure 15 This is a three-dimensional schematic diagram of a sound insulation unit in some embodiments of the present invention when it is a Helmholtz resonator.

[0048] Figure 16 yes Figure 15 The diagram shows a cross-sectional view of the sound insulation unit.

[0049] Figure 17 yes Figure 15 The diagram shows a cross-sectional view of the sound insulation unit.

[0050] Figure 18 This is a three-dimensional schematic diagram of the sound insulation unit in some embodiments of the present invention when it is a side branch pipe structure.

[0051] Figure 19 This is a cross-sectional schematic diagram of the sound insulation unit in some embodiments of the present invention.

[0052] Figure 20 This is a comparison chart of the sound insulation curves of three different sound insulation structures in this invention. Detailed Implementation

[0053] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0054] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0055] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0056] Some embodiments of the present invention propose a sound insulation structure, such as Figure 1 As shown, it includes a frame 2 and multiple sound insulation units 1.

[0057] The frame 2 is provided with multiple mounting holes 20. The sound insulation unit 1 is located in the mounting holes 20 and connected to the frame 2. The frame 2 is made of viscoelastic porous material and is an open-pore porous material. Viscoelastic porous material has the characteristics of both damping material and porous material. Compared with rigid material, viscoelastic porous material is relatively soft and can be deformed, converting mechanical vibration energy into heat energy and dissipating it.

[0058] In this invention, the frame 2 connecting multiple sound insulation units 1 is made of a viscoelastic porous material, which disconnects the sound insulation units and forms a weak connection. Sound waves attenuate as they propagate within the frame 2, significantly reducing the vibration of the frame 2. Furthermore, the frame 2, being made of a viscoelastic porous material, has an extremely low probability of being excited into resonance. Therefore, as long as the low-frequency sound insulation effect of each sound insulation unit 1 is guaranteed, the overall sound insulation effect of the sound insulation structure can be ensured, reliably guaranteeing sound insulation performance. Since the size of the sound insulation unit 1 can be made very small, the resonant frequency can become very high, thereby increasing the working frequency band of the sound insulation effect.

[0059] Furthermore, porous materials have a lower density than solid materials, resulting in a lighter overall structure that maintains the lightweight characteristics of sound insulation. This makes them more advantageous in applications with high load requirements, such as automobiles, high-speed trains, and airplanes. The lower density also further reduces costs.

[0060] The specific material of the viscoelastic porous material is not limited, as long as it can achieve damping energy dissipation between multiple sound insulation units 1 and has a porous structure. Examples of viscoelastic porous materials include polyester fiber, glass fiber, rock wool, foamed rubber, or foamed polyester.

[0061] Preferably, the material of the frame 2 is polyester fiber (specifically, an aggregate of polyester fibers). Polyester fiber is a good porous material with excellent flexibility and sound absorption properties. The following description primarily uses the example of the frame 2 being made of polyester fiber material; however, it is understood that the frame 2 can also be made of other materials. Optionally, the polyester fiber material used to make the frame 2 has a porosity of 0.97, a flow resistance of 74000 Pa·s / m², a thermal characteristic length of 7.58E-5 m, a viscous characteristic length of 4.96E-4 m, and a tortuosity factor of 1.02.

[0062] Figure 1 Some embodiments of the sound insulation structure are shown, which include a rectangular plate-shaped frame 2 ( Figure 2 The frame 2 is shown, and it has multiple rectangular mounting holes 20. Optionally, the frame 2 is made of 20mm thick polyester fiberboard, and the mounting holes 20 are cut out by cutting. The center distance between two adjacent mounting holes 20 in the side length direction is 250mm. The size of the mounting holes 20 is adapted to the size of the sound insulation unit 1. For example, if the size of the sound insulation unit 1 is 240mm*240mm*20mm, then the size of the mounting holes 20 is also 240mm*240mm. The mounting holes 20 are distributed in a rectangular array on the frame 2.

[0063] Since some sound waves are transmitted through porous materials, it is generally believed in the art that porous materials do not possess good sound insulation properties and are not used as the frame of sound insulation unit 1. However, the applicant unexpectedly discovered that the sound insulation effect can be effectively improved by controlling the area ratio of porous materials in the structure. Specifically, such as... Figure 3 As shown, the solid portion between adjacent mounting holes 20 has a center line 22 (the center line 22 is equidistant from the edge lines of the mounting holes 20 on both sides), and the center line 22 surrounding the mounting holes 20 forms a lattice, which includes hollow mounting holes 20 and solid portions 21 located outside the mounting holes 20. Figure 3 The cross-sectional lines show the regions corresponding to the solid portions of the lattice. The ratio of the total area S1 of the solid portions 21 of the lattice to the area S2 enclosed by the outer contour of the lattice should be controlled to be less than or equal to 30%.

[0064] When the area ratio of porous material is small, in the overall structure combining sound insulation unit 1 and porous material frame 2, sound insulation unit 1 significantly improves the overall impedance, so porous material can actually have a very good sound insulation effect. Furthermore, due to the effect of porous material, the structure also adds sound absorption. That is, by selecting porous material of appropriate area as the frame, sound absorption can be further introduced, thus forming an integrated sound absorption and insulation structure. This integrated sound absorption and insulation structure, when used on a wall, can further enhance the sound insulation effect due to its sound absorption properties.

[0065] by Figures 1 to 3 Taking the illustrated sound insulation structure as an example, in the figure, the mounting holes 20 and the sound insulation unit 1 are arranged in a rectangular array, and multiple crystal lattices are also arranged in a rectangular array. In this structure, the impedance variation relationship of the porous material in the crystal lattice conforms to the following distribution:

[0066]

[0067] Where Zmat is the acoustic impedance of the porous material itself, Stot is the area of ​​the porous material + sound insulation unit 1 (that is, the area of ​​the lattice), Smat is the area of ​​the porous material in the lattice, and Zp is the impedance of the porous material under the composite effect.

[0068] In the case above, the lattice size is 250mm*250mm, the sound insulation unit 1 is 240mm*240mm, and the remaining area is the area of ​​porous material. Therefore, the porous material actually only occupies 7.84% of the area. Thus, the composite impedance Zp of the porous material in the entire lattice is actually increased by approximately 13 times. This explains why the sound insulation performance improves after the area ratio of the porous material decreases.

[0069] When using porous materials as the frame 2, its area should be the focus of the design. Generally speaking, taking into account the difficulty of processing, the stability of the frame, and the sound insulation performance, the area occupied by the porous material in the entire lattice should be controlled at 2% to 30%, that is, the ratio of the area S1 of the solid part of the lattice 21 to the area S2 enclosed by the outer contour of the lattice is 2% to 30%.

[0070] The higher the acoustic impedance of a porous material, the better, but it should be within a reasonable processing range and still retain the property of sound wave penetration (that is, the porous material should be an open-cell porous material, not a closed-cell porous material). The impedance and flow resistance of open-cell porous materials are directly related.

[0071]

[0072] in

[0073]

[0074]

[0075] For the density of air, As a tortuosity factor, Porosity For flow resistance, Angular frequency, Let L be the viscosity coefficient of air, Lv be the viscous characteristic length, and Lth be the thermal characteristic length. The specific heat rate of air. Where is atmospheric pressure, Pr is Prandtl number, and j is the imaginary number sign.

[0076] It can be seen that when the flow resistance is The larger the value, the greater the impedance of the material; the greater the density and flow resistance of the porous material, the better the sound insulation effect. Optionally, the flow resistance of the porous material is... Its density is 50 kg / m³ 3 ~600 kg / m 3 This can effectively improve sound insulation.

[0077] like Figure 4 As shown, Figure 4 The diagram shows the sound insulation curves of three different sound insulation structures. The dotted curve represents the sound insulation curve of a single thin-film sound insulation unit. The rectangular dotted curve represents the sound insulation curve of a sound insulation structure (thin-film sound insulation material + porous material frame, hereinafter referred to as Structure 1) containing an array of thin-film sound insulation units and a frame 2 made of polyester fiberboard. The triangular dotted curve represents the sound insulation curve of a large-size structure (hereinafter referred to as Structure 2) formed by connecting multiple thin-film sound insulation units together via an aluminum frame. Structure 1 and Structure 2 have the same external dimensions and contain the same size and number of thin-film sound insulation units.

[0078] from Figure 4 As can be seen, a single thin-film sound insulation unit (dot curve) has good sound insulation effect in the low-frequency range (50Hz~300 Hz) due to boundary conditions. However, due to insufficient film tension, the film will resonate around 500Hz, causing sound wave transmission and a decrease in sound insulation.

[0079] In structure 2, multiple thin-film sound insulation units are connected by an aluminum frame to form a large structure (triangular curve). Due to the increased size, the frame resonates around 100 Hz, causing a rapid decrease in overall sound insulation. Then, overall anti-resonance occurs, increasing sound insulation again, followed by another resonance and a decrease in sound insulation. It is evident that as the size increases, the low-frequency sound insulation effect decreases significantly. This is even with a relatively small overall structure; if there are more units and the structure is larger, the frame resonance frequency will be even lower, resulting in even worse low-frequency performance.

[0080] Structure 1, after using viscoelastic porous material as the frame (rectangular dot curve), shows a significant increase in low-frequency sound insulation, approaching the sound insulation effect of a single thin-film sound insulation unit. This demonstrates that even with an increased overall size, the sound insulation effect does not decrease after using viscoelastic porous material as the frame.

[0081] It should be noted that the sound insulation characteristics of a thin-film sound insulation unit are mainly determined by two factors: first, the tension of the membrane; and second, the rigidity of the honeycomb structure. If the membrane is not taut (very loose), the membrane adhered to the honeycomb structure will easily vibrate, thus easily resonating, and the sound insulation will gradually decrease, reaching its lowest point at resonance. If the honeycomb structure is also not strong or rigid enough, it will also easily resonate, reducing the sound insulation. This will result in... Figure 4 The sound insulation is at its lowest point at the first resonant frequency.

[0082] Conversely, if the membrane is subjected to high prestress (tightly stretched), and the honeycomb structure is also rigid, the sound insulation will remain consistently high when the two are bonded together, resulting in a high resonant frequency. When this combination is combined with a polyester fiber frame, below the resonant frequency, due to the high sound insulation of the membrane + honeycomb structure, sound waves propagate from point 2 of the polyester fiber frame, resulting in a very stable sound insulation, resembling a straight line (e.g., Figure 20 (The triangle curve in the middle).

[0083] so Figure 4 The sound insulation curve of structure 1 shows a trough because the thin-film sound insulation unit was manufactured rather loosely, leading to a first-order resonance at 500Hz. Figure 20 The triangle curve in the image remains essentially horizontal because the thin-film sound insulation unit is manufactured with high strength, has good film tension, and a very high resonant frequency. In other words, even when the film of the thin-film sound insulation unit is relatively loose and the honeycomb structure has moderate rigidity, it can still achieve good sound insulation at low frequencies.

[0084] In some embodiments, to ensure a reliable connection between the sound insulation unit 1 and the frame 2, the outer periphery of the sound insulation unit 1 and the frame 2 can be glued together. This glued connection achieves a seal, eliminating gaps and preventing sound waves from leaking out. For example, hot melt adhesive can be used to connect the sound insulation unit 1 and the frame 2; the adhesive layer itself has a damping effect, reducing the impact on overall sound insulation.

[0085] In some embodiments, such as Figures 5 to 7 As shown, the sound insulation unit 1 has a slot 10 on its outer periphery, and the frame 2 is fitted into the slot 10. Since the frame 2 is made of polyester fiberboard or other viscoelastic porous materials, it can be easily inserted into the slot 10, making installation very convenient. Furthermore, the outer edge of the sound insulation unit 1 covers the outer periphery of the mounting hole 20 of the frame 2, which helps to improve the sound insulation effect.

[0086] In other embodiments, such as Figures 8 to 10 As shown, the sound insulation structure includes two fixing plates 3 respectively connected to the two surfaces of the frame 2. The fixing plates 3 have through holes 30 corresponding to the mounting holes 20, with the through holes 30 being smaller than the mounting holes 20. The fixing plates 3 cover the outer edge of the sound insulation unit 1. In other words, a slot is formed between the two fixing plates 3 and the frame 2 located between the two fixing plates 3, for inserting the sound insulation unit 1. The fixing plates 3 are also made of a viscoelastic porous material, such as polyester fiberboard, which is elastic and allows the sound insulation unit 1 to be easily inserted into the mounting holes 20. The two fixing plates 3 limit the front and rear sides of the sound insulation unit 1. Optionally, the through holes 30 and the mounting holes 20 are contoured. The material of the fixing plates 3 can be the same as or different from the material of the frame 2, and the materials of the front and rear fixing plates 3 can also be the same or different. The fixing plate 3 mainly serves to fix the middle sound insulation unit 1, and has little impact on the sound insulation effect. Therefore, the material of the fixing plate 3 can be slightly thinner, with a thickness of 3mm to 24mm. The frame 2 needs to be thicker, with a thickness of ≥9mm, to ensure good sound insulation effect.

[0087] In embodiments where the sound insulation unit 1 has a slot 10 or where the frame 2 has fixing plates 3 on both sides, the sound insulation unit 1 is limited and its outer edges are covered by each other, so the sound insulation unit 1 and the frame 2 no longer need to be glued together. Of course, they can still be glued together to improve the fixing effect and better eliminate gaps. In addition to glued connections, other connection methods can be used, including but not limited to bolt fixing, binding (staple fixing), and snap-fit ​​connections. Preferably, non-damping materials or porous materials are not introduced during fixing to reduce interference with the sound insulation effect.

[0088] In addition to being single-layered, the frame 2 can also be multi-layered. The frame 2 and the fixed plates 3 located on both sides of the frame 2 form a frame unit. The sound insulation structure can have two or more stacked frame units. Figure 11 In the illustrated embodiment, the sound insulation structure includes four layers of fixed plates 3, two layers of frame 2, and two layers of sound insulation units 1. Adjacent frame units may also share one layer of fixed plates 3, such as... Figure 12 As shown, the sound insulation structure includes three layers of fixed plates 3, two layers of frame 2, and two layers of sound insulation units 1.

[0089] The type of sound insulation unit 1 is not limited. Next, an example of sound insulation unit 1 will be given to illustrate it.

[0090] In some embodiments, such as Figure 13 and Figure 14 As shown, the sound insulation unit 1 is a thin-film sound insulation unit, which includes a supporting substrate 11 with a honeycomb structure and a thin film 12 disposed on the surface of the supporting substrate 11. The thin film 12 is stretched on the surface of the supporting substrate 11. The number of supporting substrates 11 can be one or two. When there are two, the thin film 12 is located between the two supporting substrates 11. The thin-film sound insulation unit is an existing technology. Its supporting substrate 11 is generally made of materials such as honeycomb aluminum or honeycomb paperboard. Then, a pre-stressed thin film (a stretched film) is attached to the surface of the honeycomb substrate to seal the through holes of the honeycomb. With such a structure, if the perimeter of the honeycomb structure of the supporting substrate 11 is fixed, it will have a good sound insulation effect. For a single thin-film sound insulation unit, if the perimeter of the supporting substrate 11 is fixed, its low-frequency sound insulation performance is good, with a sound insulation of 20dB~30dB starting from 100Hz, until the "supporting substrate with fixed perimeter" resonates, at which point the sound insulation drops significantly.

[0091] This application achieves weak connections between multiple thin-film sound insulation units by setting the frame 2, thereby reducing the impact of overall resonance. At this time, the overall resonance is determined by the resonance of the sound insulation unit 1 itself. Since the size of the sound insulation unit 1 is very small, the resonance frequency can become very high, thereby increasing the working frequency band of the sound insulation effect. It is understandable that the material properties of the frame 2 itself make it difficult to excite resonance. Even if the sound insulation unit 1 resonates, the frame 2 has good damping characteristics and can absorb the resonance energy, which increases the loss of the sound insulation unit 1 during resonance, further reducing the impact of resonance.

[0092] For thin-film sound insulation units, the low-frequency sound insulation effect of sound insulation unit 1 can be adjusted by its size. Generally, the smaller the size of sound insulation unit 1, the higher the resonant frequency, the wider the effective frequency band, and the better the effect. Optionally, the size of sound insulation unit 1 is set to be less than 1 / 5 of the working wavelength. For example, if you want to operate stably at 1 kHz, and the wavelength of 1 kHz is 0.34m, then the size (length and width) of sound insulation unit 1 should be controlled within 7cm; similarly, to reach 10kHz, the unit should be controlled within 7mm. Considering the complexity of actual production, processing, and assembly, the unit size cannot be too small. Optionally, the size of sound insulation unit 1 is 5mm~500mm, which can provide good sound insulation in the low-frequency range. For a rectangle, the size of sound insulation unit 1 is its longer side; for a hexagon, the size of sound insulation unit 1 is the length of its diagonal; and for a circle, the size of sound insulation unit 1 is its diameter. For an irregular sound insulation unit 1, the size of the sound insulation unit 1 can be understood as the length of the line connecting the two furthest points on its outer contour (viewing from the front).

[0093] In some embodiments, the sound insulation unit 1 is a resonant sound insulation structure, which differs from the characteristics of a thin-film sound insulation unit. The sound insulation of a thin-film sound insulation unit decreases when resonance occurs, while the sound insulation of a resonant sound insulation structure increases when resonance occurs. To achieve good sound insulation, the resonant frequency of the resonant sound insulation structure can optionally be 40Hz~500Hz, and more preferably 50Hz~300Hz. The resonant sound insulation structure can be, for example, a Helmholtz resonator or a side-branch structure.

[0094] Figures 15 to 17 In the illustrated embodiment, the sound insulation unit 1 is a Helmholtz resonator, comprising a flat shell 13 with an inner cavity 130 and an opening 131 connecting the inner cavity 130 to the outside. The shell 13 includes two opposing plates 132 and a side frame 133 connected between the two plates 132. The shape of the side frame 133 is consistent with the overall shape of the shell 13. The illustrated shell 13 is cuboid, while the side frame 133 encloses it to form a rectangle. The side frame 133 is composed of multiple side plates; in the illustration, the side frame 133 is formed by connecting four side plates, with the opening 131 located on one of the side plates. In other embodiments, the four side plates can also be integral, for example, formed by folding a long strip of material. The shell 13 can be made of rigid materials such as plastic, metal, rubber, or wood.

[0095] Figure 18 and Figure 19In the illustrated embodiment, the sound insulation unit 1 is a side-branch pipe structure, which also includes a flat shell 13. The difference is that one side of the shell 13 is directly connected to the outside, that is, no opening is provided on the side frame 133, and the side frame 133 is set in a semi-enclosed shape to directly form an opening. In the figure, the shell 13 also includes two oppositely arranged plates 132 and a side frame 133 connected between the two plates 132. The difference is that the side frame 133 is semi-enclosed, which includes three side plates. The three side plates are connected in a U-shape so that one side of the shell 13 is directly connected to the outside, without forming an opening 131 with a sudden change in cross-section. It can be understood that the cross-section of the opening is basically the same as the cross-section of the shell 13.

[0096] Optionally, the two plates 132 are connected by support columns 134 to reduce large-area resonance and reduce deformation of the two plates 132, ensuring adequate space within the shell 13. Multiple support columns 134 can be used; due to their small size, they do not affect the acoustic performance of the resonant sound insulation structure. Simultaneously, they improve the structural stability of the sound insulation unit 1, thereby ensuring sound insulation performance.

[0097] Taking a side branch pipe structure as an example, such as Figure 18 As shown, its length, width, and height are L1, L2, and L3, respectively, and the area of ​​the opening is L2*L3. L3 is much smaller than L1 and L2. After the sound wave enters the cavity (the internal space of the shell), it can only propagate along the L1 direction. The resonant frequency of this structure is directly related to the length of the propagation direction.

[0098]

[0099] Where c0 is the speed of sound in air, L1 is the length in the direction of sound wave propagation, n=1,3,5... are odd numbers, and f is the resonant frequency of the structure.

[0100] In some embodiments, L1=L2=300mm, L3=20mm, the shell 13 and the frame 2 are made of the same material, which is polyester fiber, with a lattice size of 320 mm. Therefore, the area ratio of polyester fiber material is 12.11%, and the first-order resonant frequency should be around 280 Hz.

[0101] like Figure 20 As shown, Figure 20 The diagram shows a comparison of the sound insulation effects of three different structures. The dotted curve represents the sound insulation of the porous material (specifically, polyester fiberboard, hereinafter referred to as Structure 3), while the triangular curve represents the sound insulation structure of the film-type sound insulation unit 1 (hereinafter referred to as Structure 4, structural reference). Figure 1The sound insulation curve of the structure is shown in the figure. The rectangular dot curve is the sound insulation curve of the sound insulation structure (hereinafter referred to as structure 5) when the sound insulation unit 1 is a side branch pipe structure. Structure 4 and structure 5 are different only in the structure of the sound insulation unit 1. They have the same external dimensions and both include a fixing plate. The thickness of the polyester fiber board of structure 3 is the same as that of structure 4 and structure 5.

[0102] Depend on Figure 20 As can be seen, the sound insulation is improved within a certain frequency range after adopting the side-branch structure, reaching its maximum near 280 Hz, but then decreasing and fluctuating. The overall sound insulation is high, hovering around 30 dB; while the thin-film sound insulation unit in structure 4, due to the greater applied tension, exhibits more stable low-frequency sound insulation and does not show a first-order resonance mode. Porous materials of the same thickness maintain a consistently lower level of sound insulation.

[0103] Therefore, the sound insulation structure made of a side-branch tube has good low-frequency sound insulation effect and does not have the defect of thin-film sound insulation units, where the sound insulation effect decreases as the film tension decreases with aging. The sound insulation effect is more stable. The performance of the Helmholtz resonator is similar to that of the side-branch tube structure.

[0104] It is understandable that, in addition to a thin-film sound insulation unit, a Helmholtz resonator, or a side branch tube, the sound insulation unit 1 can also be other structures, such as a sealed (plastic) box or other structures with better sound insulation.

[0105] It should be noted that, in the absence of conflict, the various embodiments described herein can be combined with each other to obtain more implementation schemes.

[0106] The above are merely specific embodiments of the present invention, and any improvements made based on the concept of the present invention shall be considered within the scope of protection of the present invention.

Claims

1. A sound insulation structure, characterized in that, include: Multiple sound insulation units (1); and, The frame (2) has multiple mounting holes (20). The sound insulation unit (1) is located in the mounting holes (20) and connected to the frame (2). The frame (2) is made of viscoelastic porous material, and the viscoelastic porous material is an open-pore porous material.

2. The sound insulation structure as described in claim 1, characterized in that, The viscoelastic porous material is polyester fiber, glass fiber, rock wool, foamed rubber, or foamed polyester.

3. The sound insulation structure as described in claim 1, characterized in that, The mounting holes (20) and the sound insulation unit (1) are arranged in a rectangular array. The center line (22) of the solid portion between adjacent mounting holes (20) forms a lattice. The ratio of the area S1 of the solid portion (21) of the lattice to the area S2 enclosed by the outer contour of the lattice is 2%~30%.

4. The sound insulation structure as described in claim 1, characterized in that, The flow resistance of porous materials is Its density is 50 kg / m³ 3 ~600 kg / m 3 .

5. The sound insulation structure as described in claim 1, characterized in that, The sound insulation unit (1) is glued to the outer periphery of the frame (2) to eliminate gaps.

6. The sound insulation structure as described in claim 1, characterized in that, The sound insulation unit (1) has a slot (10) on its outer periphery, and the frame (2) is fitted into the slot (10).

7. The sound insulation structure as described in claim 1, characterized in that, The sound insulation structure includes two fixing plates (3) respectively connected to the two surfaces of the frame (2). The fixing plates (3) are provided with through holes (30) corresponding to the mounting holes (20). The size of the through holes (30) is smaller than the size of the mounting holes (20). The fixing plates (3) cover the outer edge of the sound insulation unit (1).

8. The sound insulation structure according to any one of claims 1 to 7, characterized in that, The sound insulation unit (1) is a thin film type sound insulation unit, which includes a supporting substrate (11) with a honeycomb structure and a thin film (12) disposed on the surface of the supporting substrate (11), the thin film (12) sealing the holes of the honeycomb structure.

9. The sound insulation structure as described in claim 8, characterized in that, The size of the sound insulation unit (1) is 5mm~500mm.

10. The sound insulation structure according to any one of claims 1 to 7, characterized in that, The sound insulation unit (1) is a resonant sound insulation structure with a resonant frequency of 40Hz~500Hz.

11. The sound insulation structure as described in claim 10, characterized in that, The resonant sound insulation structure is a Helmholtz resonator, which includes a flat shell (13), the shell (13) having an inner cavity (130) and an opening (131) connecting the inner cavity (130) and the outside.

12. The sound insulation structure as described in claim 10, characterized in that, The resonant sound insulation structure is a side branch pipe structure, which includes a flat shell (13). The shell (13) includes two oppositely arranged plates (132) and a side frame (133) connected between the two plates (132). The side frame (133) is semi-enclosed, and one side of the shell (13) is directly connected to the outside.

13. The sound insulation structure as described in claim 12, characterized in that... The housing (13) includes a plurality of support columns (134) connected between the two plates (132), and the side frame (133) includes three connected side plates, the two connected side plates being perpendicular to each other.

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