A cavity noise reduction unit and noise reduction board based on acoustic black hole effect

Abstract

The present invention belongs to the technical field of noise control, and discloses a cavity noise reduction unit and a noise reduction board based on the acoustic black hole effect. The cavity noise reduction unit based on the acoustic black hole effect includes an acoustic black hole structure and a substrate. The acoustic black hole structure has an absorption cavity, and the substrate has a noise reduction cavity. One end of the acoustic black hole structure extends into the noise reduction cavity, and the other end thereof is connected to the substrate, and the noise reduction cavity is connected to the absorption cavity. The cavity noise reduction unit and the noise reduction board based on the acoustic black hole effect of the present invention are designed to wrap the acoustic black hole structure in the noise reduction cavity, so that the sound waves generated by the acoustic black hole structure through the sound wave transmission or sound wave reflection phenomenon are further dissipated in the noise reduction cavity, and the sound energy is converted into heat energy, thereby improving the control of noise and thus improving the noise reduction effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of noise control, and in particular relates to a cavity noise reduction unit and a noise reduction board based on acoustic black hole effect. Background Art

[0002] Noise can be seen everywhere in daily life. Noise is also considered environmental pollution. Noise not only affects normal work, but also increases the probability of heart disease and cardiovascular disease to a certain extent. At present, acoustic black hole structures are usually used to absorb noise sound waves to reduce noise. The acoustic black hole structure has a conical absorption cavity, which gradually slows down the bending wave and concentrates the energy at the tip of the absorption cavity. However, the acoustic black hole structure has a truncation thickness during manufacturing, which makes the conical absorption cavity become a truncated cone absorption cavity, so that the acoustic black hole structure is prone to sound wave transmission or sound wave reflection, resulting in poor noise reduction effect.

[0003] Therefore, the existing technology needs to be improved and developed. Summary of the invention

[0004] The purpose of the present application is to provide a cavity noise reduction unit and a noise reduction plate based on the acoustic black hole effect, which can absorb and dissipate sound waves that produce sound wave transmission or sound wave reflection, thereby improving the noise reduction effect.

[0005] In a first aspect, the present application provides a cavity noise reduction unit based on the acoustic black hole effect, comprising an acoustic black hole structure having an absorption cavity, and also comprising a substrate having a noise reduction cavity, one end of the acoustic black hole structure extending into the noise reduction cavity, and the other end thereof being connected to the substrate, and the noise reduction cavity being connected to the absorption cavity.

[0006] The cavity noise reduction unit based on the acoustic black hole effect provided in the present application is designed to wrap the acoustic black hole structure in a noise reduction cavity, so that the sound waves generated by the acoustic black hole structure through sound wave transmission or sound wave reflection phenomenon are dissipated in the noise reduction cavity, thereby improving the noise reduction effect.

[0007] Furthermore, the inner wall of the absorption chamber is provided with a spiral groove.

[0008] The present application provides a spiral groove on the inner wall of the absorption cavity to enhance the dissipation of the sound wave energy entering the absorption cavity, so as to achieve a better noise reduction effect.

[0009] Furthermore, a through hole is provided at the bottom of the substrate, and the through hole is connected to the noise reduction cavity.

[0010] The present application opens a through hole at the bottom of the substrate so that the heat in the noise reduction cavity is quickly discharged through the through hole, thereby increasing the heat loss in the noise reduction cavity.

[0011] Furthermore, the above-mentioned noise reduction cavity includes a cavity body and an extension cavity; the cavity body is connected to the absorption cavity, and the extension cavity surrounds an end of the acoustic black hole structure that is not connected to the substrate and is connected to the cavity body.

[0012] Furthermore, a raised portion is provided in the middle of the bottom of the substrate, and the raised portion protrudes toward the direction of the acoustic black hole structure.

[0013] Furthermore, a damping material is provided at the through hole.

[0014] Furthermore, the axis of the through hole is colinear with the axis of the acoustic black hole structure.

[0015] Furthermore, the through hole is in a cylindrical or truncated cone shape.

[0016] In a second aspect, the present application provides a noise reduction board, comprising a board body, on which a plurality of the above-mentioned cavity noise reduction units based on the acoustic black hole effect are provided.

[0017] Furthermore, the noise reduction plate further comprises a plurality of acoustic black hole units, and the plurality of acoustic black hole units are evenly distributed on the plate body.

[0018] From the above, it can be seen that the cavity noise reduction unit and noise reduction plate based on the acoustic black hole effect of the present invention, through the design of wrapping the acoustic black hole structure in the noise reduction cavity, make the sound waves generated by the acoustic black hole structure of sound wave transmission or sound wave reflection phenomenon be further dissipated in the noise reduction cavity, converting the sound energy into heat energy, improving the control of noise, and thus improving the noise reduction effect.

[0019] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 1 of the present application.

[0021] Figure 2 This is an AA cross-sectional view of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 1 of the present application.

[0022] Figure 3 This is a sound pressure characteristic diagram of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 1 of the present application.

[0023] Figure 4This is a sound insulation curve of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 1 of the present application.

[0024] Figure 5 A schematic diagram of the structure of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 2 of the present application.

[0025] Figure 6 This is a BB cross-sectional view of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 2 of the present application.

[0026] Figure 7 This is a sound pressure characteristic diagram of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 2 of the present application.

[0027] Figure 8 A sound insulation curve diagram of a cavity noise reduction unit based on the acoustic black hole effect provided in Example 2 of the present application.

[0028] Fig. 9 This is a schematic diagram of the structure of a noise reduction plate provided in Example 5 of the present application.

[0029] Fig.10 This is a cross-sectional view of a noise reduction plate provided in Example 5 of the present application.

[0030] Fig.11 This is a structural schematic diagram of a noise reduction plate provided in Example 6 of the present application.

[0031] Fig.12 A cross-sectional view of a noise reduction plate provided in Example 6 of the present application.

[0032] Explanation of reference numerals: 1. Cavity noise reduction unit based on acoustic black hole effect; 10. Acoustic black hole structure; 101. Absorption cavity; 1011. Spiral groove; 11. Substrate; 111. Noise reduction cavity; 1111. Cavity body; 1112. Extension cavity; 112. Through hole; 113. Protrusion; 2. Plate body; 3. Acoustic black hole unit. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0038] Embodiment 1

[0039] like Figure 1-Figure 2 As shown, the present invention is a cavity noise reduction unit 1 based on the acoustic black hole effect, including an acoustic black hole structure 10 and a substrate 11, the acoustic black hole structure 10 has an absorption cavity 101, the substrate 11 has a noise reduction cavity 111, one end of the acoustic black hole structure 10 extends into the noise reduction cavity 111, the other end of the acoustic black hole structure 10 is connected to the substrate 11, and the noise reduction cavity 111 is connected to the absorption cavity 101.

[0040] In a specific application, the absorption cavity 101 is in the shape of a hollow truncated cone, the lower bottom surface of the truncated cone is close to the noise reduction cavity 111, the upper bottom surface of the truncated cone is connected to the substrate 11, the diameter of the lower bottom surface of the truncated cone is smaller than the diameter of the upper bottom surface of the truncated cone, and the noise sound wave enters the absorption cavity 101 from the upper bottom surface side of the truncated cone, and is decelerated under the acoustic black hole effect, thereby realizing the concentration of sound wave energy, that is, the bending wave gradually slows down in the absorption cavity 101, and the sound wave energy is concentrated at one end of the lower bottom surface of the truncated cone of the absorption cavity 101. The concentrated sound wave energy enters the noise reduction cavity 111 and is dispersed and transmitted again. The sound wave will gather again in the noise reduction cavity 111, and thermal viscous friction will be generated during the gathering, thereby converting the sound energy into heat energy to achieve noise reduction.

[0041] Through this technical solution, the sound waves that cause sound wave transmission or sound wave reflection can be absorbed and dissipated, effectively improving the noise reduction effect, so there is no need to consider the influence of the truncation thickness of the acoustic black hole structure 10.

[0042] The above-mentioned truncation thickness means that the thickness of the tip of the acoustic black hole structure 10 cannot be made zero during the processing, that is, the vertex of the conical absorption cavity 101 of the acoustic black hole structure 10 is a circle, which makes the conical absorption cavity 101 become a truncated cone-shaped absorption cavity 101.

[0043] Specifically, the noise reduction cavity 111 includes a cavity body 1111 and an extension cavity 1112; the cavity body 1111 is connected to the absorption cavity 101; the extension cavity 1112 surrounds the end of the acoustic black hole structure 10 that is not connected to the substrate 11, and the extension cavity 1112 is connected to the cavity body 1111. In a specific application, the sound waves entering the noise reduction cavity 111 gather at the end of the extension cavity 1112 away from the cavity body 1111, and when the sound waves gather, thermal viscous friction is generated, which converts the sound energy into heat energy to achieve noise reduction.

[0044] In some preferred embodiments, a through hole 112 is provided at the bottom of the substrate 11, and the through hole 112 is connected to the noise reduction cavity 111. By providing the through hole 112 at the bottom of the substrate 11, the heat in the noise reduction cavity 111 is quickly discharged through the through hole 112, thereby increasing the heat loss in the noise reduction cavity 111.

[0045] Specifically, the through hole 112 can be designed in a cylindrical shape or a truncated cone shape. The openings at both ends of the cylindrical through hole 112 are of the same size, so that the heat generated in the noise reduction cavity 111 can be directly discharged without hindrance; the openings at both ends of the truncated cone through hole 112 are of different sizes, and the heat generated in the noise reduction cavity 111 enters from the end with a larger opening and is discharged from the end with a smaller opening, so that the heat can be discharged in a concentrated manner; of course, the through hole 112 can also be designed in other shapes according to actual needs. The above is only one embodiment of the present invention and should not be limited thereto.

[0046] In some preferred embodiments, the axis of the through hole 112 is colinear with the axis of the acoustic black hole structure 10. Through this technical solution, the sound waves can be more concentrated during the transmission process and a certain sound speed can be maintained, thereby ensuring the speed of noise absorption.

[0047] In some preferred embodiments, damping material is provided at the through hole 112 to further improve the control of noise. In this embodiment, the damping material is a damping paint, which is applied to the through hole 112 by spraying. Of course, the damping material can also be other materials, such as rubber or foam plastic, etc. The above is only one embodiment of the present invention and should not be limited thereto.

[0048] According to the air domain modeling of the cavity noise reduction unit 1 based on the acoustic black hole effect, the sound pressure characteristics and noise reduction effect of the incident sound wave passing through the cavity noise reduction unit 1 based on the acoustic black hole effect at different frequencies are studied, and the following are obtained: Figure 3 and Figure 4 The sound pressure characteristic diagram and sound insulation curve shown in Figure 3 From the figure, we can see the distribution of sound pressure levels at various locations inside the cavity noise reduction unit 1 based on the acoustic black hole effect. After the incident sound wave passes through the cavity noise reduction unit 1 based on the acoustic black hole effect, the sound pressure level is significantly reduced. Figure 4 It can be seen from the figure that the sound transmission loss at different frequencies is small at low frequencies (2 Hz-150 Hz) and medium frequencies (150 Hz-500 Hz is the medium-low frequency band, 500 Hz-5000 Hz is the medium-high frequency band), and does not exceed 15 decibels. At high frequencies (5000 Hz-16000 Hz), the sound transmission loss is as high as nearly 50 decibels. That is to say, the cavity noise reduction unit 1 based on the acoustic black hole effect has the best noise control effect at high frequencies.

[0049] Embodiment 2

[0050] like Figure 5-Figure 6As shown, the difference between this embodiment and embodiment one is that: in this embodiment, the inner wall of the absorption cavity 101 is provided with a spiral groove 1011, and the spiral groove 1011 can enhance the dissipation of the sound wave energy entering the absorption cavity 101 to achieve a better noise reduction effect; at the same time, a protrusion 113 is provided in the middle position of the bottom of the substrate 11, and the protrusion 113 protrudes toward the direction of the acoustic black hole structure 10. Specifically, the protrusion 113 is in the shape of a truncated cone. By arranging the protrusion 113 on the substrate 11, the sound wave energy is not only gathered at the end of the extension cavity 1112 away from the cavity body 1111, but also gathered at the position of the protrusion 113 in the cavity body 1111, so that the heat energy generated by the thermal viscous friction when the sound waves gather is gathered at the position of the protrusion 113, so that it can be discharged through the through hole 112.

[0051] Specifically, the spiral curve equation of the spiral groove 1011 is: ,in, represents the horizontal coordinate of a point on the curve in the Cartesian coordinate system, represents the ordinate of a point on the curve in the Cartesian coordinate system, represents the vertical coordinate of a point on the curve in the Cartesian coordinate system, r represents the radius of the frustum helix circle, represents the radius of the circle at the starting point of the truncated cone helix, Indicates the radius of the circle at the end point of the frustum helix. represents the pitch of the frustum helix, represents the number of turns of the truncated cone helix, is a continuous variable ranging from 0 to 1. The spiral groove 1011 is formed on the inner wall of the absorption cavity 101 by using the above spiral curve equation, so as to simulate the curve of the acoustic black hole for lofting.

[0052] According to the air domain modeling of the cavity noise reduction unit 1 based on the acoustic black hole effect, the sound pressure characteristics and noise reduction effect of the incident sound wave passing through the cavity noise reduction unit 1 based on the acoustic black hole effect at different frequencies are studied, and the following are obtained: Figure 7 and Figure 8 The sound pressure characteristic diagram and sound insulation curve shown in Figure 7 From the figure, we can see the distribution of sound pressure levels at various locations inside the cavity noise reduction unit 1 based on the acoustic black hole effect. After the incident sound wave passes through the cavity noise reduction unit 1 based on the acoustic black hole effect, the sound pressure level is significantly reduced. Figure 8It can be seen from the figures that the sound transmission loss at different frequencies is small at low frequencies (2 Hz-150 Hz) and medium frequencies (150 Hz-500 Hz is the medium-low frequency band, 500 Hz-5000 Hz is the medium-high frequency band), and does not exceed 15 decibels. At high frequencies (5000 Hz-16000 Hz), the sound transmission loss is as high as nearly 65 decibels. Compared with Example 1, the sound transmission loss is greater, indicating that the noise control effect is better.

[0053] Embodiment 3

[0054] The difference between this embodiment and the first embodiment is that in this embodiment, the inner wall of the absorption cavity 101 is provided with a spiral groove 1011. Through this technical solution, the dissipation of the sound wave energy entering the absorption cavity 101 can be enhanced to achieve a better noise reduction effect.

[0055] Specifically, the spiral curve equation of the spiral groove 1011 is: ,in, represents the horizontal coordinate of a point on the curve in the Cartesian coordinate system, represents the ordinate of a point on the curve in the Cartesian coordinate system, represents the vertical coordinate of a point on the curve in the Cartesian coordinate system, r represents the radius of the frustum helix circle, represents the radius of the circle at the starting point of the truncated cone helix, Indicates the radius of the circle at the end point of the frustum helix. represents the pitch of the frustum helix, represents the number of turns of the truncated cone helix, is a continuous variable ranging from 0 to 1. The spiral groove 1011 is formed on the inner wall of the absorption cavity 101 by using the above spiral curve equation, so as to simulate the curve of the acoustic black hole for lofting.

[0056] Embodiment 4

[0057] The difference between this embodiment and the first embodiment is that in this embodiment, the middle position of the bottom of the substrate 11 has a protrusion 113, and the protrusion 113 protrudes toward the acoustic black hole structure 10. Specifically, the protrusion 113 is in the shape of a truncated cone. Through this technical solution, the sound wave energy is gathered at the position of the protrusion 113 in the cavity body 1111, so that the heat energy generated by the hot viscous friction when the sound waves gather is gathered at the position of the protrusion 113, so that it can be discharged through the through hole 112.

[0058] Embodiment 5

[0059] like Figure 9-10As shown, the present invention provides a noise reduction board, including a board body 2, on which a plurality of cavity noise reduction units 1 based on the acoustic black hole effect in the first embodiment are arranged.

[0060] In the present embodiment, a plurality of cavity noise reduction units 1 based on the acoustic black hole effect are distributed on the board body 2 in a matrix shape. By arranging a plurality of cavity noise reduction units 1 based on the acoustic black hole effect in a matrix shape on the board body 2, the noise reduction board absorbs noise evenly, thereby ensuring a good noise reduction effect. Of course, the distribution of the plurality of cavity noise reduction units 1 based on the acoustic black hole effect on the board body 2 may also be in other shapes. The above is only one embodiment of the present invention and should not be limited to this.

[0061] In some preferred embodiments, the noise reduction board further includes a plurality of acoustic black hole units 3, and the plurality of acoustic black hole units 3 are evenly arranged on the board body 2. In specific applications, the structure of the acoustic black hole unit 3 is the same as that of the acoustic black hole structure 10, and by simultaneously arranging a plurality of cavity noise reduction units 1 based on the acoustic black hole effect and a plurality of acoustic black hole units 3 on the board body 2, the area of ​​the board body 2 can be fully utilized, and the reflection of the incident bending wave on the noise reduction board can be reduced, thereby achieving a good noise reduction effect.

[0062] It should be noted that the thickness of the cavity noise reduction unit 1 based on the acoustic black hole effect and the length of the acoustic black hole unit 3 are the same as the thickness of the board body 2, so that the thickness of the overall structure of the noise reduction board remains consistent.

[0063] Embodiment 6

[0064] like Figure 11-Figure 12 As shown, the difference between this embodiment and the fifth embodiment is that the structure of the several cavity noise reduction units 1 based on the acoustic black hole effect provided on the plate body 2 in this embodiment is the structure of the cavity noise reduction unit 1 based on the acoustic black hole effect in the second embodiment, that is, the inner wall of the absorption cavity 101 is provided with a spiral groove 1011, and at the same time, the middle position of the bottom of the substrate 11 has a protrusion 113, and the protrusion 113 protrudes toward the direction of the acoustic black hole structure 10.

[0065] Through this technical solution, when the noise reduction plate absorbs noise, the dissipation of the sound wave energy entering the absorption cavity 101 can be enhanced; at the same time, the sound wave energy can be gathered at the position of the protrusion 113 in the cavity body 1111, so that the heat energy generated by the thermal viscous friction when the sound waves gather is gathered at the position of the protrusion 113, so that it can be discharged through the through hole 112. Compared with the fifth embodiment, a better noise reduction effect can be achieved.

[0066] Embodiment 7

[0067] The difference between this embodiment and the fifth embodiment is that the structure of the several cavity noise reduction units 1 based on the acoustic black hole effect provided on the plate body 2 in this embodiment is the structure of the cavity noise reduction unit 1 based on the acoustic black hole effect in the third embodiment, that is, the inner wall of the absorption cavity 101 is provided with a spiral groove 1011.

[0068] Through this technical solution, the dissipation of the sound wave energy entering the absorption cavity 101 can be enhanced. Compared with the fifth embodiment, not only a better noise reduction effect can be achieved, but also better heat dissipation can be performed.

[0069] Embodiment 8

[0070] The difference between this embodiment and the fifth embodiment is that the structure of the several cavity noise reduction units 1 based on the acoustic black hole effect provided on the plate body 2 in this embodiment is the structure of the cavity noise reduction unit 1 based on the acoustic black hole effect in the fourth embodiment, that is, the middle position of the bottom of the substrate 11 has a protrusion 113, and the protrusion 113 protrudes toward the direction of the acoustic black hole structure 10.

[0071] Through this technical solution, the sound wave energy can be gathered at the position of the protrusion 113 in the cavity body 1111, so that the heat energy generated by the thermal viscous friction when the sound waves gather is gathered at the position of the protrusion 113, so as to be discharged through the through hole 112. Compared with the fifth embodiment, better heat dissipation can be performed.

[0072] In summary, the cavity noise reduction unit and noise reduction plate based on the acoustic black hole effect of the present invention are designed to wrap the acoustic black hole structure 10 in the noise reduction cavity 111, so that the sound waves generated by the acoustic black hole structure 10 due to sound wave transmission or sound wave reflection phenomenon are further dissipated in the noise reduction cavity 111, converting the sound energy into heat energy, thereby improving the control of noise and thus improving the noise reduction effect.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0074] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A cavity noise reduction unit based on acoustic black hole effect, comprising an acoustic black hole structure having an absorption cavity, characterized in that: It also includes a substrate, the substrate having a noise reduction cavity, one end of the acoustic black hole structure extends into the noise reduction cavity, and the other end thereof is connected to the substrate, and the noise reduction cavity is connected to the absorption cavity; The inner side wall of the absorption chamber is provided with a spiral groove; The noise reduction cavity includes a cavity body and an extension cavity; the cavity body is connected to the absorption cavity, and the extension cavity surrounds an end of the acoustic black hole structure that is not connected to the substrate and is connected to the cavity body.

2. The cavity noise reduction unit based on acoustic black hole effect according to claim 1, characterized in that: A through hole is provided at the bottom of the substrate, and the through hole is connected to the noise reduction cavity.

3. The cavity noise reduction unit based on acoustic black hole effect according to claim 1, characterized in that: A raised portion is provided in the middle of the bottom of the substrate, and the raised portion protrudes toward the acoustic black hole structure.

4. The cavity noise reduction unit based on acoustic black hole effect according to claim 2, characterized in that: The through hole is provided with a damping material.

5. The cavity noise reduction unit based on acoustic black hole effect according to claim 2, characterized in that: The axis of the through hole is colinear with the axis of the acoustic black hole structure.

6. The cavity noise reduction unit based on acoustic black hole effect according to claim 2, characterized in that: The through hole is in a cylindrical shape or a truncated cone shape.

7. A noise reduction board, comprising a board body, characterized in that: The plate body is provided with a plurality of cavity noise reduction units based on the acoustic black hole effect as described in any one of claims 1-6.

8. The noise reduction plate according to claim 7, characterized in that: It also includes a plurality of acoustic black hole units, which are evenly distributed on the plate body; the acoustic black hole units have the same structure as the acoustic black hole structure.

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