A silencing device, outdoor unit and air conditioner

Abstract

The utility model provides a kind of muffler, outdoor unit and air conditioner, it is related to air conditioning technical field, solve the technical problem that air conditioner outdoor unit compressor pipeline exists vibration noise.The muffler includes shell and high-frequency noise absorption unit and low-frequency noise absorption unit sequentially from top to bottom set in shell;High-frequency noise absorption unit includes upper layer acoustic metamaterial and the porous sound-absorbing supermaterial of setting in upper layer acoustic metamaterial top;Low-frequency noise absorption unit includes lower layer acoustic metamaterial, acoustic film being arranged in lower layer acoustic metamaterial top, damping particle being filled in lower layer acoustic metamaterial;It further include the electromagnetic controller being connected with lower layer acoustic metamaterial, the magnetic field in lower layer acoustic metamaterial is controlled by electromagnetic controller, the resonance frequency adjustment of damping particle is realized, to realize low-frequency noise absorption unit noise reduction frequency modulation.The utility model can effectively absorb the high, low frequency noise of big and small valve pipe.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning technology, and in particular to a honeycomb structure valve cover silencing device, an outdoor unit, and an air conditioner. Background Technology

[0002] In the outdoor unit of an air conditioner, the compressor, as the main moving component, will generate vibration and noise. This vibration and noise will be transmitted along the pipes and casing to the entire outdoor unit structure. When the operating frequency of the compressor is close to the modal frequency of the pipes, severe vibration and noise will be generated. Furthermore, the vibration of the pipes will cause certain deformation of the structure and reduce the reliability of the system. Therefore, controlling the vibration and noise of the compressor pipes is essential.

[0003] Commonly used methods for reducing pipeline vibration and noise in existing technologies include: 1. Increasing pipeline counterweight and reducing pipeline modal frequencies to offset the compressor excitation frequency from the pipeline resonant frequency, thus avoiding resonance. While increasing counterweight can solve some vibration and noise problems, it may cause resonance at other pipeline frequencies, making its reliability low and its effect not significant. 2. Another method is to add damping materials to the pipeline, such as rubber blocks, damping blocks, polyurethane, and other highly elastic materials, to dissipate pipeline vibration energy. However, in actual use, damping rubber pads are affected by various factors due to long-term exposure to the environment (such as temperature, light, humidity, etc.), leading to breakage of elastic molecular chains, destruction of cross-linked structures, or aging of materials, causing the damping rubber pads to harden, lose their damping effect, and lose their original elasticity and flexibility. 3. Secondly, wrapping a layer of sound insulation cotton around the compressor pipeline system can effectively reduce high-frequency noise. However, as the air conditioner ages, the noise reduction performance of the sound insulation cotton itself gradually decreases, and its noise reduction effect on low-frequency noise is not significant. Utility Model Content

[0004] The purpose of this utility model is to provide a honeycomb structure valve cover silencing device, an outdoor unit, and an air conditioner to solve the technical problem of vibration and noise in the compressor pipeline of the air conditioner outdoor unit in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This utility model provides a noise reduction device, comprising a housing and a high-frequency noise absorption unit and a low-frequency noise absorption unit arranged sequentially from top to bottom within the housing; wherein:

[0007] The high-frequency noise absorption unit includes an upper acoustic metamaterial and a porous sound-absorbing metamaterial disposed on top of the upper acoustic metamaterial.

[0008] The low-frequency noise absorption unit includes a lower acoustic metamaterial, an acoustic film disposed on top of the lower acoustic metamaterial, and damping particles filled within the lower acoustic metamaterial.

[0009] It also includes an electromagnetic controller connected to the lower acoustic metamaterial, which controls the magnetic field in the lower acoustic metamaterial to adjust the resonant frequency of the damping particles, thereby achieving noise reduction and frequency modulation of the low-frequency noise absorption unit.

[0010] The noise reduction device of this invention includes a shell, an upper acoustic metamaterial, and a lower acoustic metamaterial. A porous sound-absorbing metamaterial is disposed within the upper acoustic metamaterial to form a high-frequency noise absorption unit. Noise from the large valve pipe is first transmitted to the upper acoustic metamaterial and the porous sound-absorbing metamaterial. The porous sound-absorbing metamaterial is disposed within each honeycomb structure. When noise is transmitted to the upper acoustic metamaterial, high-frequency noise is first absorbed by the porous sound-absorbing metamaterial. The upper acoustic metamaterial, through the resonance between the structural cavity and the sound wave, can also suppress some low-frequency noise. The combination of the upper acoustic metamaterial and the porous sound-absorbing metamaterial effectively increases the noise reduction bandwidth. The lower acoustic metamaterial is filled with damping particles, and one end of the lower acoustic metamaterial is sealed with an acoustic film, while the other end is sealed with the shell, forming a closed low-frequency noise absorption unit. When sound waves reach the lower acoustic metamaterial, they resonate with the thin-film structure, reducing low-frequency noise energy. The acoustic thin-film structure and the lower acoustic metamaterial form a sealed cavity containing damping particles. As sound waves enter the lower acoustic metamaterial, the closed design allows them to interact fully with the cavity and damping particles, further enhancing low-frequency noise reduction. This silencing device effectively absorbs both high and low-frequency noise from valves of varying sizes. An electromagnetic controller connected to the lower acoustic metamaterial alters the magnetic field within it. This change in the magnetic field alters the resonance frequency between the damping particles and the metamaterial, allowing adjustment of the electromagnetic controller's magnetic field distribution to change the corresponding silencing frequency band.

[0011] Based on the above technical solution, the present invention can be further improved as follows.

[0012] As a further improvement of this utility model, the top view projection shapes of the upper acoustic metamaterial and the lower acoustic metamaterial are the same, both including an array of honeycomb acoustic metamaterials and a rhombic acoustic metamaterial formed by adjacent honeycomb acoustic metamaterials.

[0013] This invention sets both the upper and lower acoustic metamaterials to be composed of multiple honeycomb-shaped acoustic metamaterials. The honeycomb acoustic metamaterials, mimicking the shape of a honeycomb, allow sound waves to resonate multiple times with the honeycomb structure, thus achieving noise reduction. Furthermore, by forming rhomboid acoustic metamaterials between the honeycomb acoustic metamaterials, not only is space fully utilized, but the different anechoic chambers also achieve different frequency anechoic effects, expanding the anechoic bandwidth.

[0014] As a further improvement of this utility model, the porous sound-absorbing metamaterial is disposed within the honeycomb acoustic metamaterial and the rhombic acoustic metamaterial.

[0015] The combination of upper honeycomb acoustic metamaterial and porous sound-absorbing metamaterial is used to absorb high-frequency noise in sound waves. The sound waves interact with the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial. Due to the arrangement of its structure, the upper honeycomb acoustic metamaterial causes multiple resonances with each local honeycomb structure after the sound waves enter, thereby reducing high-frequency noise. The porous sound-absorbing metamaterial also has a good attenuation effect on high-frequency noise. Therefore, the combination of honeycomb acoustic metamaterial and porous sound-absorbing metamaterial has a good noise reduction effect on high-frequency noise.

[0016] As a further improvement of this utility model, the acoustic film is disposed on the top of the honeycomb acoustic metamaterial; the damping particles are filled in the inner cavity of the honeycomb acoustic metamaterial.

[0017] The combination of a lower acoustic metamaterial and damping particles is used to absorb low-frequency noise in sound waves. When sound waves enter the lower honeycomb acoustic metamaterial, they interact with the damping particles, resulting in reflection and interference that cancels each other out, effectively controlling the low-frequency noise.

[0018] As a further improvement of this utility model, the acoustic film is made of PVDF piezoelectric film.

[0019] As a further improvement of this utility model, there are multiple electromagnetic controllers, which are arranged on the outside of the housing and correspond one-to-one with the honeycomb acoustic metamaterials in the lower acoustic metamaterial.

[0020] The electromagnetic controller controls the internal magnetic field of each localized honeycomb acoustic metamaterial in the lower layer, thereby changing the resonant frequency of the damping particles within each localized honeycomb acoustic metamaterial. This achieves active control of the resonant frequency of the damping particles, enabling noise reduction and frequency modulation. The electromagnetic controller controls the magnetic field distribution of the damping particles in each honeycomb acoustic metamaterial according to the sound wave frequency. When the internal magnetic field changes, the resonant frequency of the damping particles changes, thus achieving active frequency modulation.

[0021] This utility model provides an outdoor unit, including the aforementioned silencing device.

[0022] As a further improvement of this utility model, the housing is a valve cover housing that covers the outside of the right side panel of the outdoor unit; the high-frequency noise absorption unit is disposed facing the right side panel of the outdoor unit; and the low-frequency noise absorption unit is disposed away from the right side panel of the outdoor unit.

[0023] The silencing device in the outdoor unit of this utility model is installed inside the valve cover housing. This silencing device makes full use of the space of the valve cover and can effectively eliminate the noise transmitted from the large and small valve pipes. Inside the valve cover housing, from top to bottom (inner to outer layer), an upper acoustic metamaterial, a porous sound-absorbing metamaterial, an acoustic membrane, a lower acoustic metamaterial, and damping particles are arranged sequentially. Among them, the combination of the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial is used to absorb high-frequency noise in the noise transmitted from the large and small valve pipes. The acoustic membrane seals one end of the lower acoustic metamaterial, and the housing is used to seal the other end of the lower acoustic metamaterial, thus forming a closed cavity structure. The noise after high-frequency silencing resonates with the acoustic membrane, suppressing part of the noise. The combination of the lower acoustic metamaterial and the damping particles is used to absorb low-frequency noise in the sound waves. Therefore, the silencing device can effectively absorb high and low frequency noise from the large and small valve pipes. The electromagnetic controller is used to control the internal magnetic field of each local honeycomb acoustic metamaterial in the lower layer, thereby realizing the active control of the resonance frequency of the damping particles to achieve the process of noise reduction and frequency tuning.

[0024] This utility model provides an air conditioner, including the outdoor unit.

[0025] The method for actively controlling the silencing device provided by this utility model includes at least the following steps:

[0026] Based on the size of each honeycomb acoustic metamaterial and the distribution of damping particles inside each honeycomb cavity, the initial silencing frequency of all honeycomb acoustic metamaterials is calculated.

[0027] The magnetic field distribution inside each honeycomb acoustic metamaterial is changed, and the real-time noise reduction frequency of each honeycomb acoustic metamaterial under different magnetic fields is calculated. The correspondence between the magnetic field and the real-time noise reduction frequency is then input into the electromagnetic controller.

[0028] Each electromagnetic controller senses the internal sound wave frequency of the corresponding honeycomb acoustic metamaterial. Based on the correspondence between magnetic field and frequency, it changes the magnetic field strength inside a single honeycomb acoustic metamaterial to broaden the sound attenuation bandwidth of the honeycomb acoustic metamaterial.

[0029] When the internal magnetic field of a single localized honeycomb acoustic metamaterial changes, the resonant frequency of its corresponding damping particles also changes, thereby achieving active control of noise frequency. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a three-dimensional structural diagram of the outdoor unit of this utility model;

[0032] Figure 2 This is an assembly position diagram of the right side panel and the silencer device of the outdoor unit in this utility model;

[0033] Figure 3 This is a three-dimensional structural diagram of the noise reduction device of this utility model;

[0034] Figure 4 This is a front view of the silencing device of this utility model;

[0035] Figure 5 This is a three-dimensional structural diagram of the silencing device of this utility model after removing the shell;

[0036] Figure 6 This is a schematic diagram of the upper acoustic metamaterial in the silencing device of this utility model;

[0037] Figure 7 This is a schematic diagram of the high-frequency noise absorption unit in the silencing device of this utility model;

[0038] Figure 8 This is a schematic diagram of the low-frequency noise absorption unit in the silencing device of this utility model;

[0039] Figure 9 This is a schematic diagram of the acoustic diaphragm structure in the silencing device of this utility model;

[0040] Figure 10 This is a schematic diagram of the structure of the lower acoustic metamaterial and damping particles in the silencing device of this utility model;

[0041] Figure 11 This is a control flowchart of the active control method for the silencing device of this utility model.

[0042] In the picture:

[0043] 1000, right side panel of outdoor unit;

[0044] 2000, Outdoor unit panel;

[0045] 3000, Outdoor unit top cover;

[0046] 4000, Silencing device;

[0047] 4100. Valve cover housing;

[0048] 4200, Upper-layer acoustic metamaterials;

[0049] 4300, porous sound-absorbing metamaterial;

[0050] 4400, Lower-layer acoustic metamaterials;

[0051] 4500, Acoustic thin film;

[0052] 4600, damping particles;

[0053] 4700, Electromagnetic controller;

[0054] 5000, Compressor piping structure;

[0055] 5100, Small valve pipe;

[0056] 5200, large valve pipe. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0058] Example 1

[0059] like Figures 1-10 As shown, this utility model provides a noise reduction device 4000, including a housing and a high-frequency noise absorption unit and a low-frequency noise absorption unit arranged sequentially from top to bottom within the housing; wherein:

[0060] The high-frequency noise absorption unit includes an upper acoustic metamaterial 4200 and a porous sound-absorbing metamaterial 4300 disposed on top of the upper acoustic metamaterial 4200.

[0061] The low-frequency noise absorption unit includes a lower acoustic metamaterial 4400, an acoustic film 4500 disposed on top of the lower acoustic metamaterial 4400, and damping particles filled within the lower acoustic metamaterial 4400. The damping particles 4600 are mostly composed of lightweight damping alloys and are distributed within the various local honeycomb acoustic metamaterial structures. Low-frequency sound waves interact with them and are thus suppressed.

[0062] It also includes an electromagnetic controller 4700 connected to the lower acoustic metamaterial 4400. The electromagnetic controller 4700 controls the magnetic field in the lower acoustic metamaterial 4400 to adjust the resonant frequency of the damping particles 4600, thereby achieving noise reduction and frequency modulation of the low-frequency noise absorption unit. The frequency-controllable silencing device 4000 is suitable for various operating conditions of the compressor.

[0063] It should be noted that the "from top to bottom" here refers to... Figure 5 The perspective is based on the up and down, and with Figure 1 and Figure 2 Based on the perspective, the high-frequency noise absorption unit and the low-frequency noise absorption unit are set up one inside and one outside or one on the left and one on the right. However, regardless of which direction is taken as the reference, the high-frequency noise absorption unit and the low-frequency noise absorption unit are both stacked structures, installed at the position to be silenced by opening one end of the housing, while the other end of the housing is a sealed structure.

[0064] The noise reduction device 4000 of this utility model includes a shell, an upper acoustic metamaterial 4200, and a lower acoustic metamaterial 4400. A porous sound-absorbing metamaterial 4300 is disposed within the upper acoustic metamaterial 4200 to form a high-frequency noise absorption unit. Noise from the large valve pipe 5200 is first transmitted to the upper acoustic metamaterial 4200 and the porous sound-absorbing metamaterial 4300. The porous sound-absorbing metamaterial 4300 is disposed within each honeycomb structure. When noise is transmitted to the upper acoustic metamaterial 4200, it... High-frequency noise is first absorbed by the porous sound-absorbing metamaterial 4300. The upper acoustic metamaterial 4200, through the resonance between the structural cavity and the sound waves, can also suppress some low-frequency noise. The combination of the upper acoustic metamaterial 4200 and the porous sound-absorbing metamaterial 4300 can effectively improve the silencing bandwidth. The lower acoustic metamaterial 4400 is filled with damping particles, and one end of the lower acoustic metamaterial 4400 is sealed with an acoustic film 4500, while the other end is sealed with a shell, forming a closed low-frequency noise reduction system. In the sound absorption unit, when sound waves reach the lower acoustic metamaterial 4400, they resonate with the thin film structure, thereby reducing low-frequency noise energy. Furthermore, the acoustic thin film 4500 and the lower acoustic metamaterial 4400 form a sealed cavity, inside which damping particles 4600 are arranged. When sound waves enter the lower acoustic metamaterial 4400, due to its closed structure design, the sound waves fully interact with the internal cavity and damping particles 4600, further enhancing low-frequency performance. Noise reduction performance; the noise reduction device 4000 can effectively absorb high and low frequency noise from the large and small valve pipes 5100; the electromagnetic controller 4700 is connected to the lower acoustic metamaterial 4400 and can change the magnetic field inside the lower acoustic metamaterial 4400. The change in the magnetic field inside the lower acoustic metamaterial 4400 will change the resonant frequency between the damping particles 4600 and the lower acoustic metamaterial 4400, thereby adjusting the magnetic field distribution of the electromagnetic controller 4700 can change the corresponding noise reduction frequency band.

[0065] As an optional embodiment of this utility model, such as Figures 4-6 As shown, the top view projection shapes of the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 are the same, and furthermore, their specifications and shapes are identical. Both the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 include an array of honeycomb acoustic metamaterials and a rhombus acoustic metamaterial formed by adjacent honeycomb acoustic metamaterials. In other words, four adjacent honeycomb acoustic metamaterials are combined to form a rhombus acoustic metamaterial.

[0066] like Figure 6 As shown in the figure, the diagram illustrates the structure of the upper acoustic metamaterial 4200. Of course, the structure of the lower acoustic metamaterial 4400 is the same, so no diagram is provided.

[0067] In Figure 6 In the middle, there are five rows of honeycomb acoustic metamaterials, with nine in each row, for a total of forty-five honeycomb acoustic metamaterials, and thirty-two rhombic acoustic metamaterials.

[0068] This invention sets both the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 to be composed of multiple honeycomb-shaped acoustic metamaterials. The honeycomb acoustic metamaterials, mimicking the shape of a honeycomb, allow sound waves to resonate multiple times with the honeycomb acoustic metamaterials after entering the honeycomb structure, thereby achieving noise reduction. By forming rhomboid acoustic metamaterials between the honeycomb acoustic metamaterials, not only is space fully utilized, but also different anechoic chambers are used to achieve different frequency anechoic effects and expand the anechoic bandwidth.

[0069] like Figure 5 and Figure 7 As shown, the porous sound-absorbing metamaterial 4300 is disposed within the honeycomb acoustic metamaterial and the rhombic acoustic metamaterial.

[0070] The combination of the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 is used to absorb high-frequency noise in sound waves. The sound waves will interact with the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300. Due to the arrangement of its structure, the upper honeycomb acoustic metamaterial will resonate multiple times with each local honeycomb structure after the sound waves enter, thereby reducing high-frequency noise. The porous sound-absorbing metamaterial 4300 also has a good attenuation effect on high-frequency noise. Therefore, the combination of the honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 has a good noise reduction effect on high-frequency noise.

[0071] In the design of the lower-layer honeycomb acoustic metamaterial, since the magnetic field inside each honeycomb cavity can be changed, the resonant frequency of each cavity can be designed to be different. The characteristic of the honeycomb acoustic metamaterial is that it has a high noise reduction peak at a specific frequency, but its noise reduction bandwidth is relatively narrow. When the outdoor unit of an air conditioner is running, most of its noise problems are caused by the compressor-pipeline system. As the compressor's operating frequency changes, the noise frequency band also changes. Moreover, the noise of the compressor pipeline system is broadband noise, and the noise peak may be concentrated at the compressor's fundamental frequency and the second and third harmonics of the pipeline. The noise reduction peak of a single unit often does not meet the requirements. Therefore, a lower-layer honeycomb acoustic metamaterial structure was designed. By changing the magnetic field inside each honeycomb cavity through an electromagnetic controller 4700, the noise reduction frequency corresponding to each cavity is changed, thereby improving the overall noise reduction bandwidth of the lower-layer honeycomb acoustic metamaterial.

[0072] like Figure 8 As shown, in this embodiment, the acoustic thin film 4500 is disposed on top of the honeycomb acoustic metamaterial; as Figure 9As shown, damping particles 4600 are filled in the inner cavity of the honeycomb acoustic metamaterial. By using an acoustic film 4500 to cover the top of the honeycomb acoustic metamaterial, the end of the lower acoustic metamaterial 4400 facing the upper acoustic metamaterial 4200 is a closed structure, while the lower acoustic metamaterial 4400 is connected to the inner wall structure of the shell, thus making the other end of the lower acoustic metamaterial 4400 also a closed structure, forming a closed low-frequency noise absorption unit.

[0073] The combination of the lower acoustic metamaterial 4400 and damping particles 4600 is used to absorb low-frequency noise in sound waves. After the sound waves enter the lower honeycomb acoustic metamaterial, they interact with the damping particles 4600, resulting in reflection and interference, which cancel each other out, effectively controlling the low-frequency noise.

[0074] As an optional embodiment of this utility model, the acoustic film 4500 is made of PVDF piezoelectric film.

[0075] like Figure 3 As shown, there are multiple electromagnetic controllers 4700, which are set on the outside of the housing and are set one-to-one with the honeycomb acoustic metamaterials in the lower acoustic metamaterial 4400.

[0076] It should be noted that in this embodiment, the silencer 4000 is installed on the outside of the right side panel 1000 of the outdoor unit of the air conditioner, and is installed using the valve cover housing 4100. Therefore, in the silencer 4000, the housing is the valve cover housing 4100.

[0077] The electromagnetic controller 4700 controls the internal magnetic field of each localized honeycomb acoustic metamaterial in the lower layer, thereby changing the resonant frequency of the damping particles 4600 within each localized honeycomb acoustic metamaterial. This achieves active control of the resonant frequency of the damping particles 4600, realizing noise reduction and frequency modulation. The electromagnetic controller 4700 controls the magnetic field distribution of the damping particles 4600 in each honeycomb acoustic metamaterial according to the sound wave frequency. When the internal magnetic field changes, the resonant frequency of the damping particles 4600 changes, thus realizing the active frequency modulation function. This solves the noise problem of the compressor piping structure 5000 in the outdoor unit of the air conditioner, the technical problem of difficult low-frequency noise control of the compressor piping, the problem of insignificant low-frequency vibration reduction and noise reduction effect of traditional counterweights, damping blocks, and sound insulation cotton, and the problem of difficulty in multi-band broadband noise reduction of the compressor piping.

[0078] Example 2:

[0079] like Figures 1-3 As shown, the present invention provides an outdoor unit including a silencing device 4000.

[0080] Specifically, such as Figures 1-10As shown, the silencing device 4000 includes a housing and a high-frequency noise absorption unit and a low-frequency noise absorption unit arranged sequentially from top to bottom within the housing; wherein:

[0081] like Figures 1-3 As shown, the housing is a valve cover housing 4100 that covers the outside of the right side panel 1000 of the outdoor unit; the high-frequency noise absorption unit is positioned facing the right side panel 1000 of the outdoor unit; the low-frequency noise absorption unit is positioned away from the right side panel 1000 of the outdoor unit.

[0082] The high-frequency noise absorption unit includes an upper acoustic metamaterial 4200 and a porous sound-absorbing metamaterial 4300 disposed on top of the upper acoustic metamaterial 4200.

[0083] The low-frequency noise absorption unit includes a lower acoustic metamaterial 4400, an acoustic film 4500 disposed on top of the lower acoustic metamaterial 4400, and damping particles filled within the lower acoustic metamaterial 4400.

[0084] It also includes an electromagnetic controller 4700 connected to the lower acoustic metamaterial 4400. The electromagnetic controller 4700 controls the magnetic field in the lower acoustic metamaterial 4400 to adjust the resonant frequency of the damping particles 4600, thereby achieving noise reduction and frequency modulation of the low-frequency noise absorption unit.

[0085] In this embodiment, the outdoor unit also includes an outdoor unit panel 2000, an outdoor unit top cover 3000, a compressor piping structure 5000, a small valve pipe 5100, and a large valve pipe 5200.

[0086] By installing the silencing device 4000 inside the valve cover housing 4100, the space of the valve cover is fully utilized, and the noise transmitted from the large valve pipe 5200 and the small valve pipe 5100 can be effectively eliminated.

[0087] It should be noted that the "from top to bottom" here refers to... Figure 5 The perspective is based on the up and down, and with Figure 1 and Figure 2 Based on the perspective, the high-frequency noise absorption unit and the low-frequency noise absorption unit are set up one inside and one outside or one on the left and one on the right. However, regardless of which direction is taken as the reference, the high-frequency noise absorption unit and the low-frequency noise absorption unit are both stacked structures, installed at the position to be silenced by opening one end of the housing, while the other end of the housing is a sealed structure.

[0088] The noise reduction device 4000 of this utility model includes a shell, an upper acoustic metamaterial 4200, and a lower acoustic metamaterial 4400. A porous sound-absorbing metamaterial 4300 is disposed within the upper acoustic metamaterial 4200 to form a high-frequency noise absorption unit. Noise from the large valve pipe 5200 is first transmitted to the upper acoustic metamaterial 4200 and the porous sound-absorbing metamaterial 4300. The porous sound-absorbing metamaterial 4300 is disposed within each honeycomb structure. When noise is transmitted to the upper acoustic metamaterial 4200, it... High-frequency noise is first absorbed by the porous sound-absorbing metamaterial 4300. The upper acoustic metamaterial 4200, through the resonance between the structural cavity and the sound waves, can also suppress some low-frequency noise. The combination of the upper acoustic metamaterial 4200 and the porous sound-absorbing metamaterial 4300 can effectively improve the silencing bandwidth. The lower acoustic metamaterial 4400 is filled with damping particles, and one end of the lower acoustic metamaterial 4400 is sealed with an acoustic film 4500, while the other end is sealed with a shell, forming a closed low-frequency noise reduction system. In the sound absorption unit, when sound waves reach the lower acoustic metamaterial 4400, they resonate with the thin film structure, thereby reducing low-frequency noise energy. Furthermore, the acoustic thin film 4500 and the lower acoustic metamaterial 4400 form a sealed cavity, inside which damping particles 4600 are arranged. When sound waves enter the lower acoustic metamaterial 4400, due to its closed structure design, the sound waves fully interact with the internal cavity and damping particles 4600, further enhancing low-frequency performance. Noise reduction performance; the noise reduction device 4000 can effectively absorb high and low frequency noise from the large and small valve pipes 5100; the electromagnetic controller 4700 is connected to the lower acoustic metamaterial 4400 and can change the magnetic field inside the lower acoustic metamaterial 4400. The change in the magnetic field inside the lower acoustic metamaterial 4400 will change the resonant frequency between the damping particles 4600 and the lower acoustic metamaterial 4400, thereby adjusting the magnetic field distribution of the electromagnetic controller 4700 can change the corresponding noise reduction frequency band.

[0089] As an optional embodiment of this utility model, such as Figures 4-6 As shown, the top view projection shapes of the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 are the same, and furthermore, their specifications and shapes are identical. Both the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 include an array of honeycomb acoustic metamaterials and a rhombus acoustic metamaterial formed by adjacent honeycomb acoustic metamaterials. In other words, four adjacent honeycomb acoustic metamaterials are combined to form a rhombus acoustic metamaterial.

[0090] like Figure 6 As shown in the figure, the diagram illustrates the structure of the upper acoustic metamaterial 4200. Of course, the structure of the lower acoustic metamaterial 4400 is the same, so no diagram is provided.

[0091] In Figure 6 In the middle, there are five rows of honeycomb acoustic metamaterials, with nine in each row, for a total of forty-five honeycomb acoustic metamaterials, and thirty-two rhombic acoustic metamaterials.

[0092] This invention sets both the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 to be composed of multiple honeycomb-shaped acoustic metamaterials. The honeycomb acoustic metamaterials, mimicking the shape of a honeycomb, allow sound waves to resonate multiple times with the honeycomb acoustic metamaterials after entering the honeycomb structure, thereby achieving noise reduction. By forming rhomboid acoustic metamaterials between the honeycomb acoustic metamaterials, not only is space fully utilized, but also different anechoic chambers are used to achieve different frequency anechoic effects and expand the anechoic bandwidth.

[0093] like Figure 5 and Figure 7 As shown, the porous sound-absorbing metamaterial 4300 is disposed within the honeycomb acoustic metamaterial and the rhombic acoustic metamaterial.

[0094] The combination of the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 is used to absorb high-frequency noise in sound waves. The sound waves will interact with the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300. Due to the arrangement of its structure, the upper honeycomb acoustic metamaterial will resonate multiple times with each local honeycomb structure after the sound waves enter, thereby reducing high-frequency noise. The porous sound-absorbing metamaterial 4300 also has a good attenuation effect on high-frequency noise. Therefore, the combination of the honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 has a good noise reduction effect on high-frequency noise.

[0095] like Figure 8 As shown, in this embodiment, the acoustic thin film 4500 is disposed on top of the honeycomb acoustic metamaterial; as Figure 9 As shown, damping particles 4600 are filled in the inner cavity of the honeycomb acoustic metamaterial. By using an acoustic film 4500 to cover the top of the honeycomb acoustic metamaterial, the end of the lower acoustic metamaterial 4400 facing the upper acoustic metamaterial 4200 is a closed structure, while the lower acoustic metamaterial 4400 is connected to the inner wall structure of the shell, thus making the other end of the lower acoustic metamaterial 4400 also a closed structure, forming a closed low-frequency noise absorption unit.

[0096] The combination of the lower acoustic metamaterial 4400 and damping particles 4600 is used to absorb low-frequency noise in sound waves. After the sound waves enter the lower honeycomb acoustic metamaterial, they interact with the damping particles 4600, resulting in reflection and interference, which cancel each other out, effectively controlling the low-frequency noise.

[0097] As an optional embodiment of this utility model, the acoustic film 4500 is made of PVDF piezoelectric film.

[0098] like Figure 3 As shown, there are multiple electromagnetic controllers 4700, which are set on the outside of the housing and are set one-to-one with the honeycomb acoustic metamaterials in the lower acoustic metamaterial 4400.

[0099] It should be noted that in this embodiment, the silencer 4000 is installed on the outside of the right side panel 1000 of the outdoor unit of the air conditioner, and is installed using the valve cover housing 4100. Therefore, in the silencer 4000, the housing is the valve cover housing 4100.

[0100] The electromagnetic controller 4700 controls the internal magnetic field of each localized honeycomb acoustic metamaterial in the lower layer, thereby changing the resonant frequency of the damping particles 4600 within each localized honeycomb acoustic metamaterial. This achieves active control of the resonant frequency of the damping particles 4600, enabling noise reduction and frequency modulation. The electromagnetic controller 4700 controls the magnetic field distribution of the damping particles 4600 in each honeycomb acoustic metamaterial according to the sound wave frequency. When the internal magnetic field changes, the resonant frequency of the damping particles 4600 changes, thus achieving the active frequency modulation function.

[0101] Furthermore, such as Figures 1-3 As shown, the housing is a valve cover housing 4100 that covers the outside of the right side panel 1000 of the outdoor unit; the high-frequency noise absorption unit is positioned facing the right side panel 1000 of the outdoor unit; the low-frequency noise absorption unit is positioned away from the right side panel 1000 of the outdoor unit. By installing the silencing device 4000 inside the valve cover housing 4100, sharing the housing, not only is noise reduction achieved, but the problem of wasted space in the valve cover is also solved.

[0102] The silencing device 4000 in the outdoor unit of this utility model is installed inside the valve cover housing 4100. The silencing device 4000 makes full use of the space of the valve cover and can effectively eliminate the noise transmitted by the large valve pipe 5200 and the small valve pipe 5100. The valve cover housing 4100 is arranged from top to bottom (inner to outer layer) with an upper acoustic metamaterial 4200, a porous sound-absorbing metamaterial 4300, an acoustic film 4500, a lower acoustic metamaterial 4400, and damping particles 4600. Among them, the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 are combined to absorb the high-frequency noise in the noise transmitted by the large and small valve pipes 5100. The acoustic diaphragm 4500 seals one end of the lower acoustic metamaterial 4400, and the shell is used to seal the other end of the lower acoustic metamaterial 4400, thus forming a closed cavity structure. The noise that has been silencing at high frequencies resonates with the acoustic diaphragm 4500, suppressing some of the noise. The combination of the lower acoustic metamaterial 4400 and the damping particles 4600 is used to absorb low-frequency noise in the sound waves. Therefore, the silencing device 4000 can effectively absorb the high and low frequency noise of the large and small valve pipes 5100. The electromagnetic controller 4700 is used to control the internal magnetic field of each local honeycomb acoustic metamaterial in the lower layer, thereby realizing the process of actively controlling the resonant frequency of the damping particles 4600 to achieve noise reduction and frequency modulation.

[0103] Example 3:

[0104] like Figure 1 As shown, the present invention provides an air conditioner, including an outdoor unit.

[0105] The outdoor unit includes a 4000 muffler, such as... Figures 1-10 As shown, the silencing device 4000 includes a housing and a high-frequency noise absorption unit and a low-frequency noise absorption unit arranged sequentially from top to bottom within the housing; wherein:

[0106] The high-frequency noise absorption unit includes an upper acoustic metamaterial 4200 and a porous sound-absorbing metamaterial 4300 disposed on top of the upper acoustic metamaterial 4200.

[0107] The low-frequency noise absorption unit includes a lower acoustic metamaterial 4400, an acoustic film 4500 disposed on top of the lower acoustic metamaterial 4400, and damping particles filled within the lower acoustic metamaterial 4400.

[0108] It also includes an electromagnetic controller 4700 connected to the lower acoustic metamaterial 4400. The electromagnetic controller 4700 controls the magnetic field in the lower acoustic metamaterial 4400 to adjust the resonant frequency of the damping particles 4600, thereby achieving noise reduction and frequency modulation of the low-frequency noise absorption unit.

[0109] It should be noted that the "from top to bottom" here refers to... Figure 5The perspective is based on the up and down, and with Figure 1 and Figure 2 Based on the perspective, the high-frequency noise absorption unit and the low-frequency noise absorption unit are set up one inside and one outside or one on the left and one on the right. However, regardless of which direction is taken as the reference, the high-frequency noise absorption unit and the low-frequency noise absorption unit are both stacked structures, installed at the position to be silenced by opening one end of the housing, while the other end of the housing is a sealed structure.

[0110] The noise reduction device 4000 of this utility model includes a shell, an upper acoustic metamaterial 4200, and a lower acoustic metamaterial 4400. A porous sound-absorbing metamaterial 4300 is disposed within the upper acoustic metamaterial 4200 to form a high-frequency noise absorption unit. Noise from the large valve pipe 5200 is first transmitted to the upper acoustic metamaterial 4200 and the porous sound-absorbing metamaterial 4300. The porous sound-absorbing metamaterial 4300 is disposed within each honeycomb structure. When noise is transmitted to the upper acoustic metamaterial 4200, it... High-frequency noise is first absorbed by the porous sound-absorbing metamaterial 4300. The upper acoustic metamaterial 4200, through the resonance between the structural cavity and the sound waves, can also suppress some low-frequency noise. The combination of the upper acoustic metamaterial 4200 and the porous sound-absorbing metamaterial 4300 can effectively improve the silencing bandwidth. The lower acoustic metamaterial 4400 is filled with damping particles, and one end of the lower acoustic metamaterial 4400 is sealed with an acoustic film 4500, while the other end is sealed with a shell, forming a closed low-frequency noise reduction system. In the sound absorption unit, when sound waves reach the lower acoustic metamaterial 4400, they resonate with the thin film structure, thereby reducing low-frequency noise energy. Furthermore, the acoustic thin film 4500 and the lower acoustic metamaterial 4400 form a sealed cavity, inside which damping particles 4600 are arranged. When sound waves enter the lower acoustic metamaterial 4400, due to its closed structure design, the sound waves fully interact with the internal cavity and damping particles 4600, further enhancing low-frequency performance. Noise reduction performance; the noise reduction device 4000 can effectively absorb high and low frequency noise from the large and small valve pipes 5100; the electromagnetic controller 4700 is connected to the lower acoustic metamaterial 4400 and can change the magnetic field inside the lower acoustic metamaterial 4400. The change in the magnetic field inside the lower acoustic metamaterial 4400 will change the resonant frequency between the damping particles 4600 and the lower acoustic metamaterial 4400, thereby adjusting the magnetic field distribution of the electromagnetic controller 4700 can change the corresponding noise reduction frequency band.

[0111] As an optional embodiment of this utility model, such as Figures 4-6As shown, the top view projection shapes of the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 are the same, and furthermore, their specifications and shapes are identical. Both the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 include an array of honeycomb acoustic metamaterials and a rhombus acoustic metamaterial formed by adjacent honeycomb acoustic metamaterials. In other words, four adjacent honeycomb acoustic metamaterials are combined to form a rhombus acoustic metamaterial.

[0112] like Figure 6 As shown in the figure, the diagram illustrates the structure of the upper acoustic metamaterial 4200. Of course, the structure of the lower acoustic metamaterial 4400 is the same, so no diagram is provided.

[0113] In Figure 6 In the middle, there are five rows of honeycomb acoustic metamaterials, with nine in each row, for a total of forty-five honeycomb acoustic metamaterials, and thirty-two rhombic acoustic metamaterials.

[0114] This invention sets both the upper acoustic metamaterial 4200 and the lower acoustic metamaterial 4400 to be composed of multiple honeycomb-shaped acoustic metamaterials. The honeycomb acoustic metamaterials, mimicking the shape of a honeycomb, allow sound waves to resonate multiple times with the honeycomb acoustic metamaterials after entering the honeycomb structure, thereby achieving noise reduction. By forming rhomboid acoustic metamaterials between the honeycomb acoustic metamaterials, not only is space fully utilized, but also different anechoic chambers are used to achieve different frequency anechoic effects and expand the anechoic bandwidth.

[0115] like Figure 5 and Figure 7 As shown, the porous sound-absorbing metamaterial 4300 is disposed within the honeycomb acoustic metamaterial and the rhombic acoustic metamaterial.

[0116] The combination of the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 is used to absorb high-frequency noise in sound waves. The sound waves will interact with the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300. Due to the arrangement of its structure, the upper honeycomb acoustic metamaterial will resonate multiple times with each local honeycomb structure after the sound waves enter, thereby reducing high-frequency noise. The porous sound-absorbing metamaterial 4300 also has a good attenuation effect on high-frequency noise. Therefore, the combination of the honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 has a good noise reduction effect on high-frequency noise.

[0117] like Figure 8 As shown, in this embodiment, the acoustic thin film 4500 is disposed on top of the honeycomb acoustic metamaterial; as Figure 9As shown, damping particles 4600 are filled in the inner cavity of the honeycomb acoustic metamaterial. By using an acoustic film 4500 to cover the top of the honeycomb acoustic metamaterial, the end of the lower acoustic metamaterial 4400 facing the upper acoustic metamaterial 4200 is a closed structure, while the lower acoustic metamaterial 4400 is connected to the inner wall structure of the shell, thus making the other end of the lower acoustic metamaterial 4400 also a closed structure, forming a closed low-frequency noise absorption unit.

[0118] The combination of the lower acoustic metamaterial 4400 and damping particles 4600 is used to absorb low-frequency noise in sound waves. After the sound waves enter the lower honeycomb acoustic metamaterial, they interact with the damping particles 4600, resulting in reflection and interference, which cancel each other out, effectively controlling the low-frequency noise.

[0119] As an optional embodiment of this utility model, the acoustic film 4500 is made of PVDF piezoelectric film.

[0120] like Figure 3 As shown, there are multiple electromagnetic controllers 4700, which are set on the outside of the housing and are set one-to-one with the honeycomb acoustic metamaterials in the lower acoustic metamaterial 4400.

[0121] It should be noted that in this embodiment, the silencer 4000 is installed on the outside of the right side panel 1000 of the outdoor unit of the air conditioner, and is installed using the valve cover housing 4100. Therefore, in the silencer 4000, the housing is the valve cover housing 4100.

[0122] The electromagnetic controller 4700 controls the internal magnetic field of each localized honeycomb acoustic metamaterial in the lower layer, thereby changing the resonant frequency of the damping particles 4600 within each localized honeycomb acoustic metamaterial. This achieves active control of the resonant frequency of the damping particles 4600, enabling noise reduction and frequency modulation. The electromagnetic controller 4700 controls the magnetic field distribution of the damping particles 4600 in each honeycomb acoustic metamaterial according to the sound wave frequency. When the internal magnetic field changes, the resonant frequency of the damping particles 4600 changes, thus achieving the active frequency modulation function.

[0123] Furthermore, such as Figures 1-3 As shown, the housing is a valve cover housing 4100 that covers the outside of the right side panel 1000 of the outdoor unit; the high-frequency noise absorption unit is positioned facing the right side panel 1000 of the outdoor unit; the low-frequency noise absorption unit is positioned away from the right side panel 1000 of the outdoor unit.

[0124] The silencer 4000 is arranged outside the large valve pipe 5200 and small valve pipe 5100 of the right side panel 1000 of the outdoor unit. When the air conditioner is running, the sound of the compressor and the pipeline will often be transmitted along the large valve pipe 5200 and small valve pipe 5100. The valve cover housing 4100 in the current market only plays a protective role and does not have any noise reduction effect on the compressor pipeline. The silencer 4000 of this utility model is installed inside the valve cover housing 4100 to suppress the noise transmitted from the large valve pipe 5200 and small valve pipe 5100 of the compressor pipeline structure 5000.

[0125] The silencing device 4000 in the outdoor unit of this utility model is installed inside the valve cover housing 4100. The silencing device 4000 makes full use of the space of the valve cover and can effectively eliminate the noise transmitted by the large valve pipe 5200 and the small valve pipe 5100. The valve cover housing 4100 is arranged from top to bottom (inner to outer layer) with an upper acoustic metamaterial 4200, a porous sound-absorbing metamaterial 4300, an acoustic film 4500, a lower acoustic metamaterial 4400, and damping particles 4600. Among them, the upper honeycomb acoustic metamaterial and the porous sound-absorbing metamaterial 4300 are combined to absorb the high-frequency noise in the noise transmitted by the large and small valve pipes 5100. The acoustic diaphragm 4500 seals one end of the lower acoustic metamaterial 4400, and the shell is used to seal the other end of the lower acoustic metamaterial 4400, thus forming a closed cavity structure. The noise that has been silencing at high frequencies resonates with the acoustic diaphragm 4500, suppressing some of the noise. The combination of the lower acoustic metamaterial 4400 and the damping particles 4600 is used to absorb low-frequency noise in the sound waves. Therefore, the silencing device 4000 can effectively absorb the high and low frequency noise of the large and small valve pipes 5100. The electromagnetic controller 4700 is used to control the internal magnetic field of each local honeycomb acoustic metamaterial in the lower layer, thereby realizing the process of actively controlling the resonant frequency of the damping particles 4600 to achieve noise reduction and frequency modulation.

[0126] Example 4:

[0127] like Figure 11 As shown, the method for actively controlling the silencing device 4000 in Embodiment 1, Embodiment 2, or Embodiment 3 of this utility model includes at least the following steps:

[0128] Step S1: Calculate the initial silencing frequency of all honeycomb acoustic metamaterials based on the size of each honeycomb acoustic metamaterial and the distribution of damping particles 4600 inside each honeycomb cavity.

[0129] Step S2: Change the magnetic field distribution inside the cavity of each honeycomb acoustic metamaterial, calculate the real-time noise reduction frequency of each honeycomb acoustic metamaterial under different magnetic fields, and input the correspondence between the magnetic field and the real-time noise reduction frequency into the electromagnetic controller 4700.

[0130] Step S3: Each electromagnetic controller 4700 senses the internal sound wave frequency of the corresponding honeycomb acoustic metamaterial. Based on the correspondence between magnetic field and frequency, it changes the magnetic field magnitude inside a single honeycomb acoustic metamaterial to broaden the noise reduction bandwidth of the honeycomb acoustic metamaterial. When the internal magnetic field of a single local honeycomb acoustic metamaterial changes, the resonant frequency of its corresponding damping particle 4600 changes, thereby achieving active control of noise frequency.

[0131] It should be noted that in this embodiment, the honeycomb acoustic metamaterial, acoustic film 4500, and damping particles 4600 are all existing technology products. This utility model does not improve upon existing technology materials, so they will not be described in detail. Low-frequency noise and high-frequency noise are also relative concepts, and are commonly used noise values ​​in outdoor units in the air conditioning field.

[0132] First, it should be noted that "inward" refers to the direction towards the center of the storage space, while "outward" refers to the direction away from the center of the storage space.

[0133] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0134] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0135] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0136] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0137] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0138] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A noise reduction device, characterized in that, It includes a housing and a high-frequency noise absorption unit and a low-frequency noise absorption unit arranged sequentially from top to bottom within the housing; wherein: The high-frequency noise absorption unit includes an upper acoustic metamaterial and a porous sound-absorbing metamaterial disposed on top of the upper acoustic metamaterial. The low-frequency noise absorption unit includes a lower acoustic metamaterial, an acoustic film disposed on top of the lower acoustic metamaterial, and damping particles filled within the lower acoustic metamaterial. It also includes an electromagnetic controller connected to the lower acoustic metamaterial, which controls the magnetic field in the lower acoustic metamaterial to adjust the resonant frequency of the damping particles, thereby achieving noise reduction and frequency modulation of the low-frequency noise absorption unit.

2. The silencing device according to claim 1, characterized in that, The top view projection shapes of the upper acoustic metamaterial and the lower acoustic metamaterial are the same, both including an array of honeycomb acoustic metamaterials and a rhomboid acoustic metamaterial formed by adjacent honeycomb acoustic metamaterials.

3. The silencing device according to claim 2, characterized in that, The porous sound-absorbing metamaterial is disposed within the honeycomb acoustic metamaterial and the rhombic acoustic metamaterial.

4. The silencing device according to claim 2, characterized in that, The acoustic film is disposed on top of the honeycomb acoustic metamaterial; the damping particles are filled in the inner cavity of the honeycomb acoustic metamaterial.

5. The silencing device according to claim 1, characterized in that, The acoustic film is made of PVDF piezoelectric film.

6. The silencing device according to claim 2, characterized in that, The electromagnetic controllers are multiple in number and are disposed on the outside of the housing, corresponding one-to-one with the honeycomb acoustic metamaterials in the lower acoustic metamaterial.

7. An outdoor unit, characterized in that, Includes the silencing device as described in any one of claims 1-6.

8. The outdoor unit according to claim 7, characterized in that, The housing is a valve cover housing that covers the outside of the right side panel of the outdoor unit; the high-frequency noise absorption unit is positioned facing the right side panel of the outdoor unit; the low-frequency noise absorption unit is positioned away from the right side panel of the outdoor unit.

9. An air conditioner, characterized in that, Includes the outdoor unit as described in any one of claims 7-8.

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