WO2011082510A1

WO2011082510A1 - Compound sound absorption device with built-in resonant cavity

Info

Publication number: WO2011082510A1
Application number: PCT/CN2010/001613
Authority: WO
Inventors: 张倩; 吕亚东; 杨军
Original assignee: 中国科学院声学研究所
Priority date: 2010-01-08
Filing date: 2010-10-14
Publication date: 2011-07-14
Also published as: CN101727894B; EP2487677A1; EP2487677A4; EP2487677B1; CN101727894A

Abstract

A compound sound absorption device with a built-in resonant cavity (5) comprises: a perforated board (1) perforated with several first holes (6), a backboard (2) and side boards (3), and the perforated board (1), backboard (2) and side boards (3) constitute a sealed hollow cavity; at least one or more than one resonant cavities (5) are arranged in the sealed hollow cavity, and at least one or more than one second holes (6') are distributed on the resonant cavities (5), and wherein at least one of the second holes (6') is communicated with the sealed hollow cavity; the volume of the resonant cavity (5) is 10 to 1×10¹⁰mm³, the thickness of the wall of the resonant cavity (5) is 0.05 to 10mm, and the aperture of the second hole (6') on the resonant cavity (5) is 0.05 to 100mm, and the perforated percentage of the second hole (6') is 0.01 to 30 percent. Sound dispersion is generated in the sealed hollow cavity with the resonant cavity (5), and the sound damping is enhanced with the second holes (6') and the purpose of coupling and resonance among multi-cavities is achieved in the invention. The invention has flexible design, and helps to enhance sound absorption effect and to expand the frequency band of sound absorption.

Description

Composite sound absorbing device with built-in resonant cavity

Technical field

The present invention relates to a composite sound absorbing device, and more particularly to a composite sound absorbing device having a built-in resonant cavity.

Background technique

There are many types of sound absorbing materials and sound absorbing structures used in noise control engineering. According to their sound absorption principles, they can be roughly classified into porous sound absorbing materials and resonant sound absorbing materials. For example, fiber materials and mortar materials are all porous sound absorbing materials, and thin plate resonance sound absorbing structures, thin film resonant sound absorbing structures, and perforated plate resonance sound absorption are all resonance sound absorbing materials. Ma Dazhao's "The Theory and Design of Micro-Perforated Plate Sound Absorption Structure" published in "Chinese Science" in 1975 and the article on "Micro-slot Acoustic Body Theory" published in the Journal of Acoustics in 2000, will resonate The application of sound absorbing structures has expanded into a wider field.

Although the perforated plate resonance sound absorbing structure, the micro-perforated plate sound absorbing structure and the double-layer micro-perforated plate sound absorbing structure have many advantages in sound absorption characteristics, flow resistance, moisture resistance, corrosion resistance, sanitary cleaning, etc. Features, but still can not meet the actual needs of some noise control, especially in the case where the sound absorption space is strictly limited, it is somewhat powerless to control the low frequency noise, because for the general resonance sound absorption structure, to enhance its low frequency sound absorption, It is necessary to greatly increase the depth of the cavity, which is often impossible to apply in the actual project. The G10K is currently searched, and the G10K 1 1/172 is searched for and the comparative literature is found: Chinese patent ZL 00100641. X "Tube-type perforated plate Resonant sound absorbing device" and Chinese patent ZL00264613. 7 "multi-cavity parallel side-supporting muffler".

The main feature of the patented "tube bundle perforated plate resonance sound absorbing device" is that the tube bundle type perforated plate resonance sound absorbing structure is composed of a perforated plate and a bottom plate, side plates (three closed closed cavities) and a tube bundle. The tube bundle is composed of a plurality of elongated tubes (which can be curved flexible tube bundles) having the same diameter as the perforated plate, and the length of the flexible tube bundle is not limited by the depth of the resonant sound absorbing structure of the perforated plate (the design can be short and varied, Tuning the resonant frequency and changing the sound absorption coefficient at different frequencies), the tube bundle length can be less than the cavity depth, and can be much larger than the cavity depth. The structure utilizes the sound absorption principle of the cavity coupling resonance to increase the sound absorption coefficient and the sound resistance, and improve the low frequency sound absorption effect. fruit. The current sound absorption band of the tube bundle perforated plate is limited to the middle and low frequency, and the sound absorption band is not wide enough. The length of the tube bundle is very important for the tube bundle type perforated plate resonance sound absorption structure. If the tube length is too short, it is sucked Sound performance will have a great impact, greatly reducing the sound absorption performance. Therefore, if you want to ensure better sound absorption performance, you must use a longer tube bundle, and the depth of the back cavity will increase accordingly, which is not conducive to the popularization and use of the device. The tube bundle design is single, and the sound absorption characteristics of the lumen coupling resonance and the contribution of the length of the tube bundle to the consumption of sound energy cannot be fully utilized.

The main feature of the patented "multi-cavity parallel bypass muffler" is that the multi-cavity parallel side-supporting resonance muffler is used in the intake system of the internal combustion engine of the automobile, including the intake pipe and 2-4 resonant cavities arranged in parallel, and the resonant cavity is placed. In a housing, each resonant cavity is sequentially connected to an axially disposed radial through hole on the intake pipe through a conduit. The size of the radial through hole and the conduit are matched according to the intake noise spectrum of the internal combustion engine, and the muffler can be greatly reduced. The gas noise can increase the power of the internal combustion engine and the volume is small.

Experts in the field of international acoustics and noise control have been pondering and hoping for a broadband sound absorbing structure with efficient low-frequency sound absorption in a limited thickness to replace or compensate for the traditional sound absorbing structure with low frequency absorption. To this end, the present invention proposes a composite sound absorbing device with a built-in resonant cavity that combines acoustic scattering on the surface of a resonant cavity, small hole silencing, and resonant cavity coupling resonance to achieve improved sound absorption coefficient and widened sound absorption. The purpose of the band.

Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite sound absorbing device having a built-in resonant cavity in order to overcome the drawbacks of the current noise control using the low frequency sound absorption in the above method.

The invention relates to a composite sound absorbing device with a built-in resonant cavity, the device comprises a perforated plate, a back plate and a side plate which are provided with a plurality of first holes, and the perforated plate, the back plate and the side plates are closed. a cavity, wherein: at least one or more resonant cavities are disposed in the closed cavity; and at least one or more second holes are distributed on the resonant cavity, wherein at least one The second hole is connected to the closed cavity; the volume of the resonant cavity is V=10匪³ 〜 l X 10 ^1Q mm ³ , the wall thickness is 0. 05mm~10mm; the aperture of the second hole is d ' = 01%〜30%。 0. 05~100匪, the perforation rate σ ' is 0. 01%~30%.

The resonant cavity may be: a sphere, an ellipsoid or a polyhedron; the second hole directly communicates with the closed cavity or communicates with the closed cavity through the tube bundle; if the resonance When there are a plurality of cavities, they are placed directly in the closed cavity or respectively in a closed cavity divided by a plurality of partitions.

As a modification of the present invention, the first hole or the second hole may be connected to one end of the tube bundle, the tube bundle is located in the closed cavity for increasing the acoustic resistance; and the other end of the tube bundle on the second hole is The closed cavity may be connected to communicate with a second hole in the other resonant cavity or to communicate with the first hole in the perforated plate.

The tube bundle may be a metal tube, a glass tube, a plastic tube or a rubber tube; if the tube bundle is a rubber tube bundle, the first transition joint is installed at the tube bundle port by bonding with the first hole or the second hole; The first hole is connected or the second transition joint is connected to the second hole at the tube bundle port; if the tube bundle is a metal tube bundle, a glass tube bundle or a plastic tube bundle, by bonding, welding, screwing, one injection molding and the first A hole or a second hole is connected, a first transition joint is installed at the bundle port to connect with the first hole or a second transition joint is connected to the second hole at the bundle port.

The first hole diameter d = 0.1 1~5匪, the perforation rate σ is 0.1%~30%, and the arrangement is a regular triangle. Arranged or squared, or irregularly arranged; the cavity depth of the closed cavity is D=10~2000mm, and the closed cavity may be a cylindrical cavity of one side or a polyhedral cavity of a plurality of side plates.

As a further improvement of the present invention, the back surface of the perforated plate may be coated with a porous sound absorbing material, the porous sound absorbing material in the closed cavity; ~ 200mm.

In the above technical solution, the perforated plate is an iron plate, a steel plate, a copper plate, a stainless steel plate, an aluminum plate, a plastic plate, a glass plate, a PVC plate, a PE plate or a wood board.

L〜100mm。 The length of the tube bundle 1 is 1~5000匪, the diameter is 0. l~ 100mm, the length of the tube bundle is 1~5000匪, the diameter of the tube is 0. l~ 100mm .

The composite sound absorbing device with a built-in resonant cavity of the present invention comprises a perforated plate with a hole, a back plate, a side plate and a plurality of resonant cavities. The resonant cavity is a small cavity placed in the closed cavity. The function of the resonant cavity is mainly sound divergence, connecting closed cavity and increasing acoustic resistance; when the acoustic wave reaches the resonant cavity, pushing the second cavity in the resonant cavity The air column is reciprocatingly vibrated. Due to the viscous damping effect, part of the acoustic energy is converted into heat energy, which makes use of the principle of the Helmholtz resonator. The hole in the cavity wall of the resonant cavity is the original perforation. Board The structure increases the acoustic resistance, fully consumes the sound energy, and enhances the sound absorption; the hollow design of the resonant cavity adds acoustic resistance to the sound absorbing device, and the resonant cavity and the closed cavity are connected in series to achieve multi-cavity coupling resonance. The purpose is to broaden the sound absorption band; the resonant cavity and the second hole can be designed to be of different sizes to tune the resonant frequency and change the sound absorption coefficient at different frequencies. The invention utilizes a resonant cavity to form acoustic scattering in a closed cavity, and a second hole to increase acoustic resistance to consume acoustic energy, and a multi-cavity coupled resonance sound absorption principle to modulate the resonance absorption peak and the sound absorption band, Sound resistance and sound quality help to improve the sound absorption and widen the sound absorption band.

The main technical features of the present invention include: The "composite sound absorbing device with built-in resonant cavity" of the present invention connects the resonant cavity and the closed cavity through the second hole to achieve the purpose of coupling resonance between the cavity, and broadens the sound absorption band. In addition, there is no limitation on the number of holes in the resonant cavity, so that the acoustic resistance is added to the entire sound absorbing device, and the number and diameter of the holes can be adjusted as needed to adjust the size of the acoustic resistance and improve the sound absorption coefficient; The tube bundle on the cavity prolongs the thickness of the hole in the resonant cavity, which not only helps to increase the acoustic resistance, but also connects the resonant cavity with the tube bundle, which is beneficial to the coupling resonance between the cavities and is beneficial to improve the sound absorption. Coefficient and widening the sound absorption band, and causing the sound absorption band to shift to the low frequency, which is beneficial to the low frequency sound absorption; the coupling resonance between the resonant cavity and the closed cavity can be regarded as the double-layer structure of the muffling in the same cavity. The treatment reduces the volume of the rear cavity and achieves the sound-absorbing effect of the double-layer sound absorbing structure, which is beneficial to use in an environment where the space is strictly restricted; The muffling frequency range of the composite sound absorbing device of the vibrating cavity can design the resonant cavity and the second hole to have different shapes and shapes, and the design is flexible, and is suitable for various occasions requiring muffling treatment; The acoustic scattering on the surface of the cavity enables the sound waves to reach each of the resonant cavities in the back cavity, and pushes the air column in the second hole to reciprocate, fully consuming the sound energy, which is beneficial to make full use of the back cavity space to achieve sound absorption. the goal of.

The invention has the advantages that a plurality of resonant cavities are added in the limited back cavity space, and the sound absorption, the acoustic resistance of the holes and the sound absorption principle of the multi-cavity coupling resonance, and the cavity and the hole size are fully utilized. Modulation characteristics of the resonance absorption peak and the sound absorption band, thereby increasing the sound absorption coefficient, enhancing the effective absorption of the medium and low frequency noise, and broadening the sound absorption band.

DRAWINGS

1 is a schematic view of a composite sound absorbing device with a built-in resonant cavity of the present invention, that is, each of the total The vibrating cavity has a second hole directly communicating with the closed cavity;

2 is a schematic structural view of another embodiment of the composite sound absorbing device of the present invention, that is, each of the resonant cavity bodies has twenty-six second holes communicating with the closed cavity;

3 is a schematic structural view of another embodiment of the composite sound absorbing device of the present invention, that is, each resonant cavity has four second holes, and one of the second holes communicates with a first hole in the perforated plate through the tube bundle, and the other The second hole is directly connected to the closed cavity;

4 is a schematic structural view of another embodiment of the composite sound absorbing device of the present invention, that is, each resonant cavity has three second holes, and one of the second holes communicates with the closed cavity through a tube bundle;

5 is a schematic structural view of another embodiment of the composite sound absorbing device of the present invention, that is, each resonant cavity has two second holes, and each of the two resonant cavity bodies is connected by a bundle of tubes, and the other The two holes are directly connected to the closed cavity;

6 is a schematic view of a composite sound absorbing device with a first transition joint and a second transition joint installed in the present invention;

7 is a schematic structural view of another embodiment of the composite sound absorbing device of the present invention, that is, each resonant cavity has two second holes having different diameters;

8 is a schematic structural view of another embodiment of the composite sound absorbing device of the present invention, that is, two kinds of resonant cavities having different volumes in the closed cavity;

Figure 9 is a schematic view showing the structure of another embodiment of the composite sound absorbing device of the present invention, that is, a resonant cavity having an ellipsoid and a cube in the closed cavity;

Figure 10 is a schematic view of a composite sound absorbing device with a partition plate installed in the present invention;

Figure 11 is a schematic view showing the structure of another embodiment of the composite sound absorbing device of the present invention, that is, the first hole in the perforated plate is connected with a tube bundle;

Figure 12 is a schematic view showing the structure of another embodiment of the composite sound absorbing device of the present invention, that is, a porous sound absorbing material is applied to the back surface of the perforated plate;

Figure 13 is a comparison diagram of the sound absorbing performance of the resonant sound absorbing device and the perforated plate of the present invention measured by the standing wave tube (cavity depth: 50 匪);

Figure 14 is a comparison diagram of the sound absorbing performance of a composite sound absorbing device having different numbers of resonant cavities of the present invention measured by a standing wave tube (cavity depth: 100 mm);

Figure 15 is a comparison of the mid-low frequency sound absorption performance of the composite sound absorbing device with the built-in resonant cavity measured by the standing wave tube and the tube bundle perforated plate (cavity depth 50 匪). Drawing identification:

1. Perforated plate 2. Back? 3.

4, the tube bundle 5, the resonant cavity 6, the first hole 6 ', the second hole 7, the first transition ^ V, the second

9, porous sound absorbing materials, concrete examples

The invention will be described in detail below with reference to the drawings and specific embodiments. Example 1

Referring to Figure 1, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of stainless steel, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 40 匪, and the perforated plate 1 has a side length of 80. The square stainless steel plate has a thickness of 5 inches, and the perforated plate 1 is provided with a first hole 6, the first hole 6 has a diameter of 3 mm, the first hole 6 has a perforation rate of 28%, and the first hole 6 of the perforated plate 1 is arranged. The method is a regular square arrangement; there are four resonant cavities 5 in the closed cavity, the aluminum cavity of the resonant cavity 5, the volume of the resonant cavity 5 is 1. 4 X 10 , the cavity wall thickness of the resonant cavity 5 is 5 mm; There is a second hole 6' in the cavity wall of the cavity 5, the aperture d' of the second hole 6' is 2匪, and the perforation rate σ' of the second hole 6' is 0. 06%; Close the cavity. Example 2

Referring to Fig. 2, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of stainless steel, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 50 mm, and the perforated plate 1 is a circle having a diameter of 100 mm. The first hole 6 has a diameter of 1. 7 mm, the first hole 6 has a perforation rate of 4.6%, and the first hole of the perforated plate 1 is a first hole. The arrangement of 6 is a regular square arrangement; there are four resonant cavities 5 in the closed cavity, the plastic spherical cavity of the resonant cavity 5, the volume of the resonant cavity 5 is 3.35 X 10 , and the cavity wall thickness of the resonant cavity 5 is 0. 4匪; cavity of the resonant cavity 5 There are 26 second holes 6' on the wall, and the second holes 6' are evenly distributed on the circumference of the three mutually perpendicular hemispheres of the sphere (16 second holes 6' on each circumference, each of the three circumferences There are 4 second holes 6' overlapping on one circumference, the second hole 6' has a hole diameter d' of 0.5 mm, and the second hole 6' has a perforation rate σ' of 0.1%; the cavity 5 is randomly placed in the closed cavity Inside.

The experimental study on the mid-low frequency muffling mechanism of the composite sound absorbing device with built-in resonant cavity was completed by the standing wave tube. The mid-low frequency sound absorption coefficient of the composite sound absorbing device of the perforated plate, the perforated plate of the spherical body in which the non-porous hole is placed in the rear cavity and the built-in resonant cavity is measured, and the multi-cavity coupling is determined to improve the sound absorption coefficient. The parameters of other resonant sound absorbing structures used in the measurement are as follows:

Perforated plate parameters: The holes are arranged in a square, the hole diameter is 1.7mm, the center distance between the holes is 7mm, the plate thickness is 0.7mm, and the back cavity depth is 50mm;

Perforated plate parameters of a sphere with no holes in the back cavity: The perforated plate holes are arranged in a square with a hole diameter of 1.7 匪, the center-to-center spacing between the holes is 7 匪, the plate thickness is 0.7 匪; 4 non-porous plastic hollows are placed in the back cavity The sphere has a wall thickness of 0.4 匪 and a volume of 3.35X10. The sphere is randomly placed in the closed cavity with a depth of 50 后.

It can be seen from Fig. 13 that the sound absorption coefficient of the perforated plate sound absorbing device of the perforated plate and the spherical body in which the non-porous hole is placed in the back cavity is similar, and the highest sound absorption coefficient is 1000 Hz and 1250 Hz, respectively, not more than 0.35, and the sound absorption effect is poor. The resonance of the composite sound absorbing device with built-in resonant cavity reaches 0.928 at 630Hz. Between 500Hz and 1250Hz, the sound absorption coefficient reaches 0.5 or more, and the frequency bandwidth reaches 750Hz or more. The absorption of the composite sound absorbing device with built-in resonant cavity can be seen. The sound effect is significantly better than the other two sound absorption effects. Example 3

Referring to Fig. 2, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of stainless steel, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 100 匪, and the perforated plate 1 has a diameter of 100 mm. The circular stainless steel plate has a thickness of 0.7 mm, and the first hole 6 is provided on the perforated plate 1. The first hole 6 has a diameter of 1.7 mm, the first hole 6 has a perforation rate of 4.6%, and the first hole 6 of the perforated plate 1 is arranged. The method is a regular square arrangement; there are 9, 7, 4 and 1 resonant cavities 5 in the closed cavity, and the resonant cavity 5 is a plastic spherical cavity. The volume of the resonant cavity 5 is 3.35X10, resonance Cavity wall of cavity 5 The thickness is 0. 4mm; there are 26 second holes 6' in the cavity wall of the resonant cavity 5, and the second hole 6' is evenly distributed on the circumference of three mutually perpendicular hemispherical surfaces of the sphere (16 on each circumference) The second hole 6' has four second holes 6' overlapping on each of the three circumferences, and the second hole 6' has an aperture d' of 0.5 匪, and the second hole 6' has a perforation rate σ ' 0. 1%; The resonant cavity 5 is randomly placed in the closed cavity.

In the experiment, four composite sound absorbing devices with built-in resonant cavity of the present invention were used, and nine, seven, four and one resonant cavities were respectively placed in the closed cavity, and the middle and low frequencies were completed by the standing wave tubes. The experimental study of the muffling mechanism determines the influence of the number of resonant cavities on the sound absorption coefficient and the bandwidth. The parameters of the other resonant sound absorbing structures used in the measurement are as follows: Perforated plate parameters: The holes are arranged in a square, the hole diameter is 1. 7 mm, the center-to-center spacing between the holes is 7 匪, the plate thickness is 0.7 mm, and the back cavity depth is 100 mm.

It can be seen from Fig. 14 that the resonant sound absorption peak of the resonant sound absorbing device having a resonant cavity in the closed cavity is at 630 Hz, the sound absorption coefficient is not greater than 0.4, and the sound absorption coefficient of 2000 Hz is about 0.6; The sound absorption coefficient of the sound absorption coefficient of the resonance sound absorption device of the four resonance chambers in the cavity is 0.02 Hz, and the sound absorption coefficient is greater than 0. 5, 2000 Hz, the sound absorption coefficient is about 0.8; The sound absorption coefficient of the resonance sound absorption device having a resonance cavity in the cavity reaches 0.95 or more at 800 Hz, and the sound absorption coefficient between 400 Hz and 800 Hz is greater than 0.5, the sound absorption coefficient of 2000 Hz is about 0.85; The sound absorption coefficient of the sound absorption coefficient of the sound absorption coefficient is about 0.8. It can be seen that as the number of resonant cavities in the closed cavity increases, the frequency bandwidth widens, and the resonant peak of the main sound absorption band gradually increases and is divided into two, and a sound absorption structure similar to the double-layer micro-perforated plate appears. Characteristics; in addition, the sound absorption coefficient at 2000 Hz also follows the cavity Increased to improve. Example 4

Referring to Fig. 3, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device comprises a perforated plate made of plastic, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 200 匪, 500 mm, 1000 mm or 2000 mm, and the perforated plate 1 031%, on the perforated plate 1 , the perforated plate 1 is a perforated plate 1 having a thickness of 2 匪, the perforated plate 1 is provided with a first hole 6 , the first hole 6 has a diameter of 2 匪, the first hole 6 perforation rate is 0. 031%, on the perforated plate 1 The first holes 6 are arranged in a manner Regular square arrangement; there are 100 resonant cavities 5 in the closed cavity, the glass cavity of the resonant cavity 5, the volume of the resonant cavity 5 is 2.7×10, the cavity wall thickness of the resonant cavity 5 is 10 mm; the cavity wall of the resonant cavity 5 There are four second holes 6', and the second holes 6' are evenly distributed on the circumference of one hemisphere of the sphere. The aperture d' of the second hole 6' is 2 mm, and the perforation rate σ' of the second hole 6' is 0.06%; three of the four second holes 6' of each cavity 5 are in communication with the closed cavity, and the other second hole 6' is connected to the first tube bundle 4, the other end of the tube bundle 4 Corresponding to the first hole 6 in the perforated plate 1; the tube bundle 4 is a metal tube, a glass tube or a plastic tube, the length 1 is 10 mm, 50 mm or 100 mm, and the diameter is 2 匪; the connection of the tube bundle 4 and the perforated plate 1 is bonding , threaded connection or one injection molding; the connection between the resonant cavity 5 and the tube bundle 4 is bonding, welding, screwing or one injection molding. Example 5

Referring to Fig. 4, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device comprises a perforated plate made of a glass plate, a PVC plate, a PE plate or a wooden board, a back plate 2 made of glass, and a side plate 3 made of glass. The closed cavity has a depth D of 100 mm. The perforated plate 1 is a square plate of 200 mm×200 mm and has a thickness of 3 匪. The perforated plate 1 is provided with a first hole 6 , the diameter of the first hole 6 is 1 awake, the perforation rate of the first hole 6 is 0.6%, and the perforated plate 1 is A hole 6 is arranged in a hexagonal arrangement; there are 16 resonant cavities 5 in the closed cavity, a rubber ball cavity in the resonant cavity 5, a volume of the resonant cavity 5 is 3.35X10, and a cavity wall thickness of the resonant cavity 5 is 0.8.匪; the cavity wall of the resonant cavity 5 has three second holes 6', the second hole 6' is evenly distributed on the circumference of one hemisphere of the sphere, and the second hole 6' has an aperture d' of lmm, the second hole The perforation rate σ' of 6' is 0.047%; the second hole 6' of each cavity 5 is connected to a tube bundle 4, and the other end of the tube bundle 4 is in communication with the closed cavity; the tube bundle 4 is a rubber tube, and the length 1 is 60 mm. , the diameter is lmm; the connection between the resonant cavity 5 and the tube bundle 4 is sticky Or injection molding; cavity 5 randomly placed in a closed cavity. Example 6

Referring to Fig. 5, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of a copper plate, a back plate 2 made of stainless steel, and a closed cavity composed of a side plate 3 made of stainless steel having a depth D of 40 匪, the perforated plate 1 being a square plate having a side length of 80 ,, a thickness of 1 mm, and a first plate on the perforated plate 1 The hole 6, the first hole 6 has a diameter of 3 mm, the first hole 6 has a perforation rate of 28%, and the first hole 6 on the perforated plate 1 is arranged in a regular square arrangement; the closed cavity has four resonant cavities 5, and the resonance The cavity 5 is a copper ball cavity, the volume of the resonant cavity 5 is 1.4×10, the cavity wall thickness of the resonant cavity 5 is 5匪; the cavity wall of the resonant cavity 5 has two second holes 6′, and the second hole 6′ is uniform Distributed on the circumference of one hemisphere of the sphere, the aperture d' of the second hole 6' is 5 mm, and the perforation rate σ' of the second hole 6' is 1.4%; each of the two resonance cavities is a group, and each group is bundled Connecting two second holes 6' on the two resonant cavities, and the other second holes 6' are connected to the closed cavity, as shown in Fig. 5; the tube bundle 4 is a steel pipe, the length is 5 mm, the diameter is 5 匪; the tube bundle 4 and the perforated plate The connection mode of 1 is bonding, screwing or one injection molding; the connection mode of the resonant cavity 5 and the tube bundle 4 is welding or screwing, resonance The cavity 5 is randomly placed in the closed cavity. Example 7

Referring to Figures 3 and 6, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of plastic, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 200 mm, and the perforated plate 1 is a square plate of 1000 mm X 1000 mm. The thickness of the perforated plate 1 is provided with a first hole 6, the first hole 6 has a diameter of 2 mm, the first hole 6 has a perforation rate of 0.031%, and the first hole 6 of the perforated plate 1 is arranged in a regular square. Arrangement; there are 100 resonant cavities 5 in the closed cavity, the plastic spherical cavity of the resonant cavity 5, the volume of the resonant cavity 5 is 2.7×10, and the cavity wall thickness of the resonant cavity 5 is 10匪; the cavity wall of the resonant cavity 5 has Two second holes 6', the second holes 6' are uniformly distributed on the circumference of one hemisphere of the sphere, the second hole 6' has a hole diameter d' of 2 mm, and the second hole 6' has a perforation rate σ' of 0.03%. a second hole 6' of each resonant cavity 5 is in communication with the closed cavity, and the other second hole 6' is connected to a tube bundle 4, and the other end of the tube bundle 4 is in communication with the first hole 6 in the perforated plate 1; The tube bundle 4 is a rubber tube having a length of 100 mm and a diameter of 2 mm; the connection of the tube bundle 4 to the perforated plate 1 Mounting a first connection transition joint Ί; cavity 5 is connected with the tube bundle 4 of the way through a second transition joints' 7 is connected to the installation. Example 8

Referring to Fig. 7, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device comprises a perforated plate made of plastic, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 200 匪, and the perforated plate 1 is 1000 匪 X 1000 The first hole 6 has a diameter of 2 匪, the first hole 6 has a diameter of 2 匪, the first hole 6 has a perforation rate of 0.031%, and the first hole 6 of the perforated plate 1 Arranged in a regular square arrangement; there are 100 resonant cavities 5 in the closed cavity, the plastic spherical cavity in the resonant cavity 5, and the volume of the resonant cavity 5 is 2. 7 X 10 ⁵ Dish ³ , the cavity wall of the resonant cavity 5 The thickness of the cavity 5 has two second holes 6' on the cavity wall, and the second holes 6' are non-uniformly distributed on the circumference of one hemisphere of the sphere, and the aperture d of the second hole 6' The aperture d' of the second hole 6' is 1 匪, and the perforation rate σ' of the second hole 6' is 0. 039%; the cavity 5 is randomly placed in the closed cavity. Example 9

Referring to Fig. 8, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device comprises a perforated plate made of a copper plate, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 40 匪, and the perforated plate 1 has a side length of 80. The square plate of the crucible has a thickness of lmm, and the perforated plate 1 is provided with a first hole 6, the first hole 6 has a diameter of 3 mm, the perforation rate of the first hole 6 is 28%, and the arrangement of the first hole 6 on the perforated plate 1 is Regular square arrangement; there are 4 resonant cavities 5 in the closed cavity, the plastic spherical cavity is in the resonant cavity 5, and there are three second holes 6' in the cavity wall of the resonant cavity 5, and the second hole 6' is evenly distributed in the sphere On the circumference of a hemispherical surface, the wall thickness of the four resonant cavities 5 is 1 mm; wherein the volume of the two resonant cavities 5 is 3.3 x 10, and the aperture of the second hole 6' above them is 2 匪. perforation was 0.19%; volume of the other two resonance chambers 5 is 8. ^³ X 10 3 mm 3, the aperture thereof above second hole 6 'is lmm, the perforations was 0.12%; cavity 5 Feel free to place in a closed cavity. Example 10

Referring to Fig. 8, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of a copper plate, a back plate 2 made of stainless steel, and a closed cavity composed of a side plate 3 made of stainless steel having a depth D of 40 匪, the perforated plate 1 being a square plate having a side length of 80 ,, a thickness of 1 mm, and a first plate on the perforated plate 1 The hole 6, the first hole 6 has a diameter of 3 mm, the first hole 6 has a perforation rate of 28%, and the first hole 6 on the perforated plate 1 is arranged in a regular square arrangement; the closed cavity has four resonant cavities 5, and the resonance The cavity 5 is a plastic cavity, and the cavity wall of each cavity 5 has a second hole 6', and the cavity walls of the four resonators 5 have a thickness of 0.5 匪; wherein the two resonators 5 are in volume 3. 3 X 10 ⁴ mm ³ ellipsoid, an aperture above them second holes 6 'is 2mm, the perforation rate of 0.063%; the other two resonant cavities with a volume of 5 6. 4 X 10 cubes, are The second hole 6' has a hole diameter of 2 mm and a perforation rate of 0.03%. The cavity 5 is randomly placed in the closed cavity. Example 11

Referring to Fig. 10, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of stainless steel, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 40 匪, and the perforated plate 1 has a side length of 80. The square stainless steel plate has a thickness of 5 inches, and the perforated plate 1 is provided with a first hole 6, the first hole 6 has a diameter of 3 mm, the first hole 6 has a perforation rate of 28%, and the first hole 6 of the perforated plate 1 is arranged. The method is a regular square arrangement; there are four resonant cavities 5 in the closed cavity, the plastic spherical cavity is in the resonant cavity 5, the volume of the resonant cavity 5 is 942匪³ , the cavity wall thickness of the resonant cavity 5 is 1 mm; the resonant cavity 5 a porch wall having a second hole 6', a second hole 6' having a diameter d' of 2 匪, a second hole 6' having a perforation rate σ' of 0.7%; a closed cavity having a partition The four resonant cavities 5 are respectively fixed in the closed cavity. Example 12

Referring to Fig. 11, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of stainless steel, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 50 mm, and the perforated plate 1 is a circle having a diameter of 100 mm. The first hole 6 has a diameter of 1. lmm, the first hole 6 has a perforation rate of 1.9%, and the first hole of the perforated plate 1 is a first hole. The arrangement of 6 is a regular square arrangement; there are four resonant cavities 5 in the closed cavity, the plastic spherical cavity of the resonant cavity 5, and the resonant cavity 5 The volume of the cavity is 3.35 X 10 , the wall thickness of the cavity 5 is 0.4 匪; the cavity wall of the cavity 5 has 26 second holes 6 ', and the second hole 6' is evenly distributed among the three spheres of the sphere On the circumference of the vertical hemisphere (16 second holes 6' on each circumference, 4 second holes 6' overlap on every two of the three circumferences), the aperture d' of the second hole 6' is 0. 5mm, the perforation rate σ ' of the second hole 6' is 0.1%; the cavity 5 is randomly placed in the closed cavity; each of the first holes 6 on the perforated plate 1 is connected to a stainless steel tube bundle 4, the tube bundle 4 long 8. 5 mm, diameter 1. lmm, the tube bundle 4 is welded to the first hole 6 of the perforated plate 1.

The comparison experiment of the middle and low frequency noise elimination mechanism of the composite sound absorbing device with the built-in resonant cavity and the tube bundle perforated plate was completed by the standing wave tube. The mid-low frequency sound absorption coefficient of the composite sound absorbing device of the perforated plate, the tube bundle perforated plate and the built-in resonance cavity was measured, and the function of adding the built-in resonance cavity to the tube bundle perforated plate sound absorbing device was determined. The parameters of other resonant sound absorbing structures used in the measurement are as follows:

Perforated plate parameters: The holes are arranged in a square, the hole diameter is 1. 7 mm, the center distance between the holes is 7 mm, the plate thickness is 0.7 mm, and the back cavity depth is 50 mm.

The tube bundle is welded to the perforated plate. The tube bundle is perforated. The hole is 1. 1mm, the center of the hole is 7匪, the plate thickness is 0. 7mm, the tube length is 8. 5mm, the diameter is 1. lmm, the tube bundle is welded on the perforated plate. On the hole, the depth of the back cavity is 50匪.

It can be seen from Fig. 15 that the main resonance frequency band of the composite sound absorbing device of the tube bundle perforated plate and the built-in resonant cavity is shifted to the low frequency compared with the perforated plate, and the average sound absorption coefficient is higher than that of the perforated plate; the composite suction of the built-in resonant cavity The formant of the acoustic device is significantly higher than the tube bundle perforated plate sound absorbing device, and the frequency band is wider than the tube bundle perforated plate. Example 13

Referring to Fig. 12, this embodiment produces a composite sound absorbing device with a built-in resonant cavity of the present invention. The device consists of a perforated plate made of stainless steel, a back plate 2 made of stainless steel and a side plate 3 made of stainless steel. The closed cavity has a depth D of 300 mm, and the perforated plate 1 is a circle having a diameter of 100 mm. The first hole 6 has a diameter of 1. lmm, the first hole 6 has a perforation rate of 1.9%, and the first hole of the perforated plate 1 is a first hole. The arrangement of 6 is a regular square arrangement; there are four resonant cavities 5 in the closed cavity, the plastic spherical cavity of the resonant cavity 5, and the resonant cavity 5 The volume is 3.35 X 10 , the cavity wall thickness of the resonant cavity 5 is 0.4 匪; the cavity wall of the resonant cavity 5 has six second holes 6 ', and the second hole 6' is evenly distributed on one hemisphere of the sphere The perforation rate σ ' of the second hole 6' is 0. 023%; the cavity 5 is randomly placed in the closed cavity; the back surface of the perforated plate 1 is covered. a porous sound absorbing material 9 is added, and the porous sound absorbing material 9 is in the closed cavity; the porous sound absorbing material 9 has a thickness of 0.5 匪, 5 匪, 30 mm, 100 匪 or 200 mm, and the porous sound absorbing material 9 is glass wool, foamed aluminum, foamed plastic, slag wool or fiber cotton.

In short, the invention patent adopts a composite sound absorbing device with a built-in resonant cavity to perform sound absorption processing, and fully utilizes the acoustic scattering on the surface of the resonant cavity, the acoustic resistance of the cavity on the resonant cavity, and the coupling resonance between the resonant cavity to absorb the resonance peak and the absorption. The modulation of the sound frequency band has a wider sound absorption band than the conventional perforated plate resonance sound absorption structure, which increases the sound absorption coefficient and enhances the effective absorption of the medium and low frequency noise. This is a compact, economical and practical composite sound absorption device with built-in resonant cavity. From the experimental study of the muffling mechanism of the composite sound absorbing device with the built-in resonant cavity completed by the standing wave tube of the embodiment, it can be seen that the sound absorbing effect of the composite sound absorbing device with built-in resonant cavity is obviously better than that of the perforated plate resonant sound absorbing device. As the number of resonant cavities in the closed cavity increases, the bandwidth widens, and the resonant peak of the main sound absorption band gradually increases and is divided into two, which is similar to the characteristics of the double-layer microperforated sound absorbing structure. The number of resonant cavities and the number of holes in the resonant cavity are essential for a composite sound absorbing device with a built-in resonant cavity. If the resonant cavity is too small, the sound absorption performance will be greatly affected, and the sound absorbing performance will be lowered.

It should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention and are not limiting. While the invention has been described in detail herein with reference to the embodiments of the embodiments of the present invention Within the scope of the claims.

Claims

Rights request

1. A composite sound absorbing device with a built-in resonant cavity, the device comprising a perforated plate, a back plate and a side plate, a plurality of first holes, the perforated plate, the back plate and the side plates forming a closed cavity, The at least one or more resonant cavities are disposed in the closed cavity; the resonant cavity is distributed with at least one or more second holes, wherein at least one second hole is Closed cavity communication; volume of the resonant cavity

l X lCTmm ^3, a wall thickness of cavity 0. 05mm~10mm; second hole on the pore size d '= 0 05~100mm, perforation rate σ.' ~ 30% to 0.01%.

2. The composite sound absorbing device with a built-in resonant cavity according to claim 1, wherein the plurality of resonant cavity bodies are directly placed in the closed cavity or respectively fixed in a closed by a plurality of partitions. Inside the cavity.

3. The composite sound absorbing device with a built-in resonant cavity according to claim 1, wherein the resonant cavity can be: a sphere, an ellipsoid or a polyhedron.

4. The composite sound absorbing device with a built-in resonant cavity according to claim 1, wherein the second hole is directly in communication with the closed cavity.

5. The composite sound absorbing device with a built-in resonant cavity according to claim 1, wherein the second hole communicates with the closed cavity through the tube bundle.

6. The composite sound absorbing device with a built-in resonant cavity according to claim 1, wherein the first hole or the second hole is connectable to one end of the tube bundle, and the tube bundle is located in the closed cavity for increasing sound Resistance.

The composite sound absorbing device with a built-in resonant cavity according to claim 6, wherein the other end of the tube bundle on the second hole can communicate with the closed cavity and communicate with the second hole on the other resonant cavity. Or connect the first hole in the perforated plate.

The composite sound absorbing device with a built-in resonant cavity according to claim 6, wherein the tube bundle can be a metal tube, a glass tube, a plastic tube or a rubber tube, and has a length of l~5000 mm and a diameter of 0. 1~ 100mm; When the tube bundle is a rubber tube bundle, it is connected to the first hole or the second hole by bonding, the first transition joint is connected to the first hole at the tube bundle port, or the second transition joint is connected to the second hole at the tube bundle port; When the tube bundle is a metal tube bundle, a glass tube bundle or a plastic tube bundle, the first transition joint and the first hole are installed in the bundle port by bonding, welding, screwing, one-shot molding, and the first hole or the second hole. Connect or install a second transition joint at the bundle port to connect to the second hole.

5〜 The first hole diameter d = 0.1 l~ The thickness of the first hole is d = 0 l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l 5mm, the perforation rate σ is 0.1%~30%; the cavity depth of the closed cavity is D=10~2000mm, and the closed cavity is a cylindrical cavity composed of one side plate or a polyhedron composed of a plurality of side plates The first hole of the perforated plate is arranged in a regular triangular arrangement or a square arrangement, or in an irregular arrangement.

The composite sound absorbing device with a built-in resonant cavity according to claim 1, wherein a back surface of the perforated plate is coated with a porous sound absorbing material, and the porous sound absorbing material is in a closed cavity. Lmn! Its thickness is 0. lmn! ~ 200mm.