Silencing unit piece, silencing device, air conditioner and air conditioner noise reduction method

Abstract

The invention belongs to the technical field of air conditioners, and discloses a silencing unit piece, a silencing device, an air conditioner and an air conditioner noise reduction method. Each silencing unit piece comprises a shell, a piezoelectric film and an electrode plate. By controlling the voltage on the electrode plate, the voltage of the piezoelectric film is further controlled, so that the stress on the surface of the piezoelectric film is changed, the vibration frequency of the piezoelectric film is finally changed, active control over the noise elimination frequency of the piezoelectric film is achieved, and noise of a specific frequency band is eliminated in a more targeted mode. The noise elimination unit is applied to the air conditioner outdoor unit, noise generated by a compressor pipeline can be effectively eliminated, particularly the problem that low-frequency noise of the compressor pipeline is difficult to control can be solved, the vibration frequency of the piezoelectric film can be actively changed by applying different voltage values to the piezoelectric film, and the noise elimination effect is improved. Therefore, the method is applied to noise generated by the compressor under various different working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to a muffler unit, a muffler device, an air conditioner and an air conditioner noise reduction method. Background Art

[0002] At present, in air-conditioning related technologies, especially in the air-conditioning outdoor unit, the compressor, as the main working component, will generate vibration and noise problems during operation. The vibration and noise will be transmitted along the pipeline and the shell to the entire outdoor unit structure, and when the operating frequency of the compressor is close to the pipeline modal frequency value, serious vibration and noise problems will occur. The vibration of the pipeline will cause a certain deformation of the outdoor unit structure and reduce the overall reliability of the outdoor unit. Therefore, it is essential to control the vibration and noise problems of the compressor pipeline.

[0003] In the prior art, the commonly used methods to reduce pipeline vibration noise include adding pipeline counterweights to reduce pipeline modal frequencies, staggering the compressor excitation frequency and pipeline resonance frequency to avoid resonance. Although adding counterweights can solve some vibration noise problems, it may cause resonance of other pipeline frequencies, and its reliability is not high and the effect is not obvious. Another method is to add damping materials to the pipeline to consume pipeline vibration energy, but the vibration-damping rubber pad will be exposed to the external environment for a long time during actual use, resulting in the breakage of the elastic molecular chain, destruction of the cross-linking structure or aging of the material, which makes the vibration-damping rubber pad harden and have no vibration-damping effect. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the existing sound-absorbing and noise-reducing methods are not effective, and therefore a sound-absorbing unit component, a sound-absorbing device, an air conditioner and an air-conditioner noise reduction method are provided.

[0005] The present invention aims to provide a sound-absorbing unit element for absorbing the noise of a vibrating device, comprising:

[0006] A shell, wherein the shell is formed with a back cavity, and an opening communicating with the back cavity is formed on one side of the shell;

[0007] A piezoelectric film, wherein the piezoelectric film is attached to the opening;

[0008] An electrode sheet, the electrode sheet is constructed as a flexible sheet, the electrode sheet is attached to the piezoelectric film and is electrically connected to the piezoelectric film, and the electrode sheet is configured to be electrically connected to a power supply;

[0009] Among them, the piezoelectric film and the electrode sheet are configured as follows: the electrode sheet can be controlled according to the noise frequency and supplied with a corresponding voltage value; the greater the voltage value supplied to the electrode sheet, the greater the stress generated by the piezoelectric film and the lower the vibration frequency of the piezoelectric film.

[0010] In some embodiments, the electrode sheet is circular and is attached to the center of the piezoelectric film.

[0011] In some embodiments, the area of ​​the electrode sheet accounts for 15% to 25% of the area of ​​the piezoelectric film.

[0012] In some embodiments, the piezoelectric film and the back cavity form a resonant sound absorber for actively absorbing low-frequency noise; a sound absorbing material is arranged on the inner wall surface of the back cavity, and the sound absorbing material is a porous structure for passively absorbing high-frequency noise.

[0013] In some embodiments, the muffler unit further comprises a controller;

[0014] An acoustic sensor is arranged on the electrode sheet;

[0015] The controller is designed to control the voltage value supplied by the power supply to the electrode sheet according to the noise signal detected by the acoustic sensor, thereby controlling the stress value of the piezoelectric film and regulating the vibration frequency of the piezoelectric film.

[0016] In some embodiments, a noise reduction device is provided, comprising:

[0017] One or more of the above-mentioned sound attenuation units;

[0018] The voltage level of each electrode sheet can be controlled independently to supply voltage.

[0019] In some embodiments, a plurality of said housings are connected together;

[0020] The electrode sheet of each of the noise reduction units is supplied with voltages of different values.

[0021] In some embodiments, an air conditioner is provided, the air conditioner comprising: a casing, a compressor pipeline is disposed in the casing;

[0022] The air conditioner further comprises the above-mentioned silencer, which is arranged in the casing and the piezoelectric film in the silencer faces the compressor pipeline.

[0023] In some embodiments, the air conditioner includes an outdoor unit, the outdoor unit includes the casing, the casing includes a top plate, a panel, a right side plate, a partition, and a base, the top plate, the panel, the right side plate, the partition, and the base form a closed space, the silencer is embedded in the partition, and the partition is close to the compressor pipeline.

[0024] In some embodiments, a method for reducing noise of the air conditioner is provided.

[0025] Obtain the noise frequency signal during air conditioning operation;

[0026] Performing frequency identification on the noise frequency signal;

[0027] The voltage supplied to the electrode sheet is controlled according to the recognition result, the stress on the piezoelectric film is changed, and the noise frequency is regulated.

[0028] The technical solution provided by the present invention has the following beneficial effects compared with the prior art:

[0029] In the silencer unit, by controlling the current on the electrode sheet, and then controlling the voltage on the electrode sheet, and then controlling the voltage generated by the current conducted by the electrode sheet on the piezoelectric film, the stress on the surface of the piezoelectric film is changed, and finally the vibration frequency of the piezoelectric film is changed, so as to realize the active control of the silencer frequency of the piezoelectric film, control the vibration frequency of the piezoelectric film to be close to or equal to the noise frequency, and eliminate the noise in a specific frequency band more targetedly. The silencer unit is applied to the outdoor unit of the air conditioner to effectively eliminate the noise generated by the compressor pipeline, especially to solve the problem of difficult control of low-frequency noise in the compressor pipeline, and by applying different voltage values ​​to the piezoelectric film, the vibration frequency of the piezoelectric film can be actively changed, so as to be applied to the noise generated by the compressor under various different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the accompanying drawings:

[0031] Figure 1 1 is a schematic diagram of the structure of a noise reduction unit according to an embodiment of the present invention;

[0032] Figure 2 1 is a schematic diagram of the structure of a muffler device according to an embodiment of the present invention;

[0033] Figure 3 is a schematic diagram of the structure of a sound absorbing material shown in an embodiment of the present invention;

[0034] Figure 4 It is one of the schematic diagrams of the air conditioner shown in the embodiment of the present invention;

[0035] Figure 5 This is the second schematic diagram of the air conditioner shown in the embodiment of the present invention;

[0036] Figure 6 is a flow chart of an air conditioning noise reduction method shown in an embodiment of the present invention;

[0037] In the figure: 1-shell, 2-back cavity, 3-piezoelectric film, 4-electrode sheet, 401-electrical connection end, 5-electrical wire, 6-acoustic sensor, 7-sound absorbing material, 8-casing, 801-top plate, 802-panel, 803-side plate, 804-base, 9-partition, 10-controller, 11-compressor pipeline.

[0038] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0039] In the description of the present invention, it should be noted that the terms "inside", "outside", etc. indicate orientations or positional relationships based on the orientations 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 a limitation on the present invention.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "contacted", 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 or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the prior art, the commonly used methods to reduce pipeline vibration noise include adding pipeline counterweights to reduce pipeline modal frequencies, staggering the compressor excitation frequency and pipeline resonance frequency to avoid resonance. Although adding counterweights can solve some vibration noise problems, it may cause resonance of other pipeline frequencies, and its reliability is not high and the effect is not obvious. Another method is to add damping materials to the pipeline to consume pipeline vibration energy, but the vibration-damping rubber pad will be exposed to the external environment for a long time during actual use, resulting in the breakage of the elastic molecular chain, destruction of the cross-linking structure or aging of the material, which makes the vibration-damping rubber pad harden and have no vibration-damping effect.

[0042] Based on this technical problem, the following embodiments are proposed.

[0043] Embodiment 1

[0044] like Figure 1 As shown, this embodiment provides a sound-absorbing unit component for absorbing the noise of a vibrating device, including:

[0045] A shell 1 is formed with a back cavity 2, and an opening communicating with the back cavity 2 is formed on one side of the shell 1;

[0046] A piezoelectric film 3 is attached to the opening;

[0047] The electrode sheet 4 is constructed as a flexible sheet, the electrode sheet 4 is attached to the piezoelectric film 3 and is electrically connected to the piezoelectric film 3, and the electrode sheet 4 is configured to be electrically connected to a power supply;

[0048] Among them, the piezoelectric film 3 and the electrode sheet 4 are configured as follows: the electrode sheet 4 can be controlled according to the noise frequency and supplied with a corresponding voltage value; the greater the voltage value supplied to the electrode sheet 4, the greater the stress generated by the piezoelectric film 3, and the lower the vibration frequency of the piezoelectric film 3.

[0049] In this embodiment, the piezoelectric film 3 adopts DE piezoelectric film, which is a new type of electroactive material with the characteristics of fast response and large deformation caused by external voltage; the electrode sheet 4 adopts flexible conductive electrode material; the electrode sheet 4 is electrically connected to the controller 10 through the electrical conductor 5, and by obtaining the noise frequency in the external environment, the controller 10 can control the current on the electrode sheet 4 according to the noise frequency, and then control the voltage of the electrode sheet 4, and then control the voltage on the piezoelectric film 3, thereby changing the stress on the surface of the piezoelectric film 3, and finally changing the vibration frequency of the piezoelectric film 3, so as to realize active control of the silencing frequency of the piezoelectric film 3. The controller 10 can make the vibration frequency of the piezoelectric film 3 close to or equal to the noise frequency, and eliminate noise in a specific frequency band in a more targeted manner.

[0050] When noise from the external environment is transmitted to the silencing unit, when the piezoelectric film 3 is affected by sound waves, the sound waves will cause a slight deformation of the piezoelectric film 3, resulting in a voltage on its surface. Applying a voltage to the piezoelectric film 3 through the electrode sheet 4 can cause the piezoelectric film 3 to vibrate in the opposite direction. This reverse vibration will produce a sound wave opposite to the incident sound wave (opposite phase), forming an interference effect. When the two sound waves meet, they will cancel each other out, thereby actively reducing or eliminating noise. While vibrating, the piezoelectric film 3 will transmit the noise to the back cavity 2. The sound wave energy of the noise will resonate in the back cavity 2 and be further dissipated, achieving a better silencing effect.

[0051] The flexible electrode material can be a carbon grease material. When the flexible electrode is powered, it will act on the piezoelectric film 3. When the piezoelectric film 3 generates voltage, the surface of the piezoelectric film 3 is subjected to stress. The greater the voltage, the greater the stress, and the lower the vibration frequency of the piezoelectric film 3. The piezoelectric film 3 can suppress low-frequency noise with longer sound waves that is not easily absorbed. The relationship between the stress on the surface of the piezoelectric film 3 and the voltage is:

[0052] V = dF / C;

[0053] Among them, V represents the surface voltage generated by the piezoelectric film 3; d is the piezoelectric constant, which describes the ability of the material to generate charge and is related to the properties of the material itself; F is the preload force on the piezoelectric film, that is, stress; C is the capacitance, which is related to the size and thickness of the piezoelectric film 3.

[0054] The silencer unit is applied to the outdoor unit of the air conditioner to effectively eliminate the noise generated by the compressor pipeline, especially to solve the problem of difficult control of low-frequency noise in the compressor pipeline. By applying different voltage values ​​to the piezoelectric film 3, the vibration frequency of the piezoelectric film 3 can be actively changed, thereby being applied to the noise generated by the compressor under various different working conditions.

[0055] Optionally, in an implementation of this embodiment, as Figure 1 As shown,

[0056] The electrode sheet 4 is circular in shape and is attached to the center of the piezoelectric film 3 .

[0057] In this embodiment, the electrode sheet 4 is circular and attached to the center of the piezoelectric film 3 to prevent the piezoelectric film 3 from wrinkling in all directions, and to ensure that the piezoelectric film 3 can effectively vibrate in a noisy environment.

[0058] Preferably, the area of ​​the electrode sheet 4 accounts for 15% to 25% of the area of ​​the piezoelectric film 3. The area of ​​the electrode sheet 4 occupies the area of ​​the piezoelectric film 3 within this range, so that the area of ​​the electrode sheet 4 remains moderate. If it exceeds this range, the electrode sheet 4 with a larger area affects the vibration of the piezoelectric film 3. If it is less than this range, the electrode sheet 4 with a smaller area cannot prevent the piezoelectric film 3 from wrinkling.

[0059] Optionally, in an implementation of this embodiment, as Figure 2 , 3 As shown,

[0060] The piezoelectric film 3 and the back cavity 2 form a resonant sound absorber for actively absorbing low-frequency noise;

[0061] A sound absorbing material 7 is arranged on the inner wall surface of the back cavity 2. The sound absorbing material 7 is a porous structure and is used for passively absorbing high-frequency noise.

[0062] In this embodiment, the sound-absorbing material 7 can be a porous fiber sound-absorbing material, such as sound-absorbing cotton, which is used to absorb high-frequency noise. When sound waves encounter porous sound-absorbing materials, part of the sound waves will enter the pores of the material. When the sound waves propagate in the pores, they will cause the vibration of air molecules in the pores. Due to the friction between the air molecules in the pores and the skeleton of the material, this friction will cause the sound energy to be converted into heat energy, which is absorbed by the material. The wavelength of high-frequency sound waves is relatively low and is easy to be absorbed. The high-frequency noise is absorbed by designing the sound-absorbing material 7, while the wavelength of low-frequency sound waves is relatively long and is not easy to be absorbed. For low-frequency noise, the piezoelectric film 3 is designed to cooperate with the back cavity 2. When the sound wave acts on the piezoelectric film 3, it will act on the piezoelectric film 3. The vibration of the piezoelectric film 3 dissipates part of the sound wave energy. At the same time, the piezoelectric film 3 will transfer the noise energy to the back cavity 2 while vibrating. The sound wave energy of the noise resonates in the back cavity 2 and is further dissipated. The controller 10 makes the vibration frequency of the piezoelectric film 3 close to or equal to the noise frequency, thereby eliminating the noise in the low-frequency band more targetedly.

[0063] Therefore, the silencer unit has a good silencer effect on noise in both low-frequency band and high-frequency band. The combination of the piezoelectric film 3 and the back cavity 2 can effectively absorb low-frequency noise, and the setting of the porous sound-absorbing material can effectively absorb high-frequency noise. The problem of poor silencer performance of traditional silencer devices is solved by setting the piezoelectric film 3, the back cavity 2 and the porous sound-absorbing material combination, and the silencer unit as a whole has a broadband silencer effect.

[0064] Optionally, in an implementation of this embodiment, as Figure 1 As shown,

[0065] The muffler unit also includes a controller 10;

[0066] An acoustic sensor 6 is provided on the electrode sheet 4;

[0067] The controller 10 is designed to control the voltage value supplied by the power supply to the electrode sheet 4 according to the noise signal detected by the acoustic sensor 6, thereby controlling the stress value of the piezoelectric film 3 so that the vibration frequency of the piezoelectric film 3 can be regulated.

[0068] In this embodiment, the two end portions of the electrode sheet 4 form electrical connection ends 401, and an electrical conductor 5 is provided on the housing 1. One end of the electrical conductor 5 is electrically connected to the electrical connection end 401 to form an electrical connection between the electrode sheet 4 and the piezoelectric film 3, and the other end is electrically connected to the controller. The number of electrical connection ends 401 is 2, and both electrical connection ends 401 are strip-shaped structures. The two electrical connection ends 401 are located on both sides of the electrode sheet 4 and are electrically connected to the electrical conductor 5 to form a closed circuit. The acoustic sensor 6 is used to detect the noise signal and transmit the noise signal to the controller 10. The controller 10 supplies power to the electrode sheet 4 through the electrical conductor 5 according to the noise signal, which acts on the surface of the piezoelectric film 3. When the piezoelectric film 3 is subjected to a direct current (dc) voltage, the piezoelectric film 3 and the back cavity 2 can resonate at a low frequency, thereby suppressing the low-frequency noise. The electrical conductor 5 can be arranged inside the back cavity 2, extending through the upper part of the back cavity 2 to be connected to the controller 10. The controller 10 can control the current on the electrode sheet 4 and then control the voltage of the electrode sheet 4 according to the noise frequency, and then control the voltage applied to the piezoelectric film 3, thereby changing the stress on the surface of the piezoelectric film 3, and finally changing the vibration frequency of the piezoelectric film 3, thereby realizing active control of the silencing frequency of the piezoelectric film 3. The controller 10 can make the vibration frequency of the piezoelectric film 3 close to or equal to the noise frequency, thereby eliminating noise in a specific frequency band in a more targeted manner.

[0069] Embodiment 2

[0070] In this embodiment, Figure 2 As shown, a muffler device is provided, comprising:

[0071] One or more sound-absorbing unit components of the first embodiment;

[0072] The voltage level of each electrode sheet 4 can be controlled individually.

[0073] Specifically, a plurality of housings 1 are connected together;

[0074] The electrode plates 4 of each silencing unit are supplied with voltages of different values.

[0075] In this embodiment, multiple shells 1 are constructed to be connected as one body. When the muffler device is composed of multiple muffler units, by controlling the voltage of the electrode sheet 4 in each muffler unit to different values, the vibration frequency of the piezoelectric film 3 is different. Compared with a single muffler unit, the muffler device has a wider muffler frequency range.

[0076] Embodiment 3

[0077] In this embodiment, Figure 4 , 5 As shown, an air conditioner is provided, the air conditioner comprising: a casing 8, a compressor pipeline 11 is arranged in the casing 8;

[0078] The air conditioner further comprises the muffler device in the second embodiment, which is arranged in the casing 8 and the piezoelectric film 3 in the muffler device faces the compressor pipeline 11 .

[0079] Specifically, the air conditioner includes an outdoor unit, the outdoor unit includes a casing 8, the casing 8 includes a top plate 801, a panel 802, a right side plate 803, a partition 9, and a base 804. The top plate 801, the panel 802, the right side plate 803, the partition 9, and the base 804 form a closed space, and the silencer is embedded in the partition 9, and the partition 9 is close to the compressor pipeline 11.

[0080] In this embodiment, the silencer is arranged at the partition 9 and the piezoelectric film 3 in the silencer faces the compressor pipeline 11. This position makes the silencer shortest from the compressor pipeline 11. The silencer can eliminate the low-frequency noise and high-frequency noise of the compressor pipeline 11 by actively combining passive methods. Figure 4 As shown, the housing 8 comprises a top plate 801, a panel 802, a side plate 803 and a base 804, and the top plate 801, the panel 802, the side plate 803 and the base 804 together form a relatively closed housing 8, as shown in FIG. Figure 5 As shown, the controller 10 is electrically connected to the silencer through the electrical conductor 5 , and the silencer has a suppressing effect on the vibration noise of the compressor pipeline 11 in the casing 8 .

[0081] The environmental noise signal is detected by the acoustic sensor 6 and transmitted to the controller 10. After receiving the electrical signal, the controller 10 can control the voltage on the electrode sheet 4 according to the noise frequency, and then control the voltage generated by the piezoelectric film 3, thereby changing the stress on the surface of the piezoelectric film 3, and finally changing the vibration frequency of the piezoelectric film 3, thereby realizing active control of the silencing frequency of the piezoelectric film 3. The controller 10 can make the vibration frequency of the piezoelectric film 3 close to or equal to the noise frequency, and eliminate the noise in a specific frequency band more specifically.

[0082] When noise from the external environment is transmitted to the silencing unit, when the piezoelectric film 3 is affected by sound waves, the sound waves will cause a slight deformation of the piezoelectric film 3, resulting in a voltage on its surface. Applying a voltage to the piezoelectric film 3 through the electrode sheet 4 can cause the piezoelectric film 3 to vibrate in the opposite direction. This reverse vibration will produce a sound wave opposite to the incident sound wave (opposite phase), forming an interference effect. When the two sound waves meet, they will cancel each other out, thereby actively reducing or eliminating noise. While vibrating, the piezoelectric film 3 will transmit the noise to the back cavity 2. The sound wave energy of the noise will resonate in the back cavity 2 and be further dissipated, achieving a better silencing effect. The controller 10 makes the vibration frequency of the piezoelectric film 3 close to or equal to the noise frequency, so as to eliminate the noise in the low frequency band more specifically. When the sound wave encounters the porous sound-absorbing material, part of the sound wave will enter the pores of the material. When the sound wave propagates in the pores, it will cause the vibration of the air molecules in the pores. Due to the friction between the air molecules in the pores and the skeleton of the material, this friction will cause the sound energy to be converted into heat energy, which will be absorbed by the material. The high-frequency sound wave has a lower wavelength and is easily absorbed. The high-frequency noise is eliminated by designing the sound-absorbing material 7, and the low-frequency noise is eliminated by designing the piezoelectric film 3 to cooperate with the back cavity 2, so that the silencer can comprehensively suppress the vibration noise of the compressor pipeline 11 in the casing 8.

[0083] The silencer device is composed of multiple silencer units and has a wider silencer frequency range, which can be applied to various working conditions of the compressor.

[0084] Embodiment 4

[0085] like Figure 6 As shown, a method for reducing noise of an air conditioner is provided, which is used for the method for reducing noise of an air conditioner in Embodiment 3.

[0086] Obtain the noise frequency signal during air conditioning operation;

[0087] Perform frequency recognition on noise frequency signals;

[0088] The voltage supplied to the electrode sheet 4 is controlled according to the recognition result, the stress on the piezoelectric film 3 is changed, and the noise frequency is regulated.

[0089] In this embodiment, during the operation of the air conditioner, the compressor starts, and the vibration noise of the compressor pipeline 11 is transmitted to the muffler. The noise frequency signal is detected by the acoustic sensor 6, and the noise frequency signal is transmitted to the controller 10. After receiving the electrical signal, the controller 10 identifies the frequency, and controls the voltage value of the piezoelectric film 3 according to the identification result, so that the surface of the piezoelectric film 3 is subjected to the stress corresponding to the voltage value. In this way, the noise of a specific frequency band can be eliminated in a targeted manner.

[0090] When the acoustic sensor 6 detects that the noise frequency signal detected is a multi-band noise frequency signal, the controller 10 identifies the frequency after receiving the electrical signal, and controls the voltage value of each piezoelectric film 3 according to the identification result, so that the surface of each piezoelectric film 3 is subjected to stress corresponding to the voltage value, thereby eliminating noise in multiple specific frequency bands.

[0091] Optionally, in this embodiment, the controller 10 has a machine learning capability to control the corresponding voltage of the piezoelectric film 3 and the stress under the corresponding voltage, so as to improve the noise elimination performance and frequency control capability of the pressure silencing device.

[0092] This learning process solves the anechoic frequency control problem by following these steps:

[0093] (1) Optimization of noise reduction performance

[0094] The noise reduction performance of the noise reduction device is analytically calculated according to the size of the back cavity 2 and the preload force of the piezoelectric film 3, and the noise reduction performance of the noise reduction device under different preload force parameters of the piezoelectric film 3 is obtained to evaluate and optimize the performance of the noise reduction device.

[0095] (2) Parameter Tuning

[0096] The particle swarm optimization algorithm is combined with the analytical prediction model (PSO) to perform optimization calculations and give the required preload force of each piezoelectric film 3 at different frequencies, thereby optimizing the preload force of the piezoelectric film to obtain the best silencing performance. Different preload forces and back cavity designs will affect the silencing frequency and silencing effect, so it is necessary to determine the optimal parameters through calculation to achieve the best silencing effect. Through this process, the required preload force of the piezoelectric film 3 at different frequencies is determined, so that the silencing device can achieve the best silencing effect at a specific frequency.

[0097] (3) Voltage calculation

[0098] Then, the voltage required by the piezoelectric film 3 under different preload forces is calculated according to the parameter characteristics of the piezoelectric film 3. This process ensures that the piezoelectric film can work under appropriate voltage in practical applications, thereby achieving effective sound wave control.

[0099] (4) Controller input

[0100] The calculated voltage of the piezoelectric film 3 and the noise absorption algorithm curve are input into the electrical controller 10, thereby completing the learning process of controlling the noise reduction frequency of the noise reduction device. This process ensures that the noise reduction device can flexibly adjust its working parameters according to real-time environmental changes to achieve a dynamic noise reduction effect.

[0101] Finally, the voltage of the piezoelectric film 3 and the noise elimination energy absorption algorithm curve of the noise elimination device are input into the controller 10, thereby completing the learning process of the noise elimination frequency control of the noise elimination device.

[0102] The learning process aims to solve the problem of noise reduction frequency control of the noise reduction device composed of piezoelectric acoustic metamaterials, so that the noise reduction device can effectively reduce noise within a specific frequency range and adapt to different noise sources. The controller 10 can automatically adjust the noise reduction frequency of the piezoelectric film 3 according to different noise sources, thereby achieving efficient and targeted noise reduction.

[0103] It should be noted that the preload force referred to in this application is the initial stress.

[0104] In summary, the ingenious design of the silencer unit is:

[0105] First, in the silencer unit, by controlling the current on the electrode sheet, and then controlling the voltage on the electrode sheet, and then controlling the voltage on the piezoelectric film, the stress on the surface of the piezoelectric film is changed, and finally the vibration frequency of the piezoelectric film is changed, so as to realize active control of the silencer frequency of the piezoelectric film, so that the vibration frequency of the piezoelectric film is close to or equal to the noise frequency, and the noise in a specific frequency band is eliminated more targetedly. The silencer unit is applied to the outdoor unit of the air conditioner to effectively eliminate the noise generated by the compressor pipeline, especially to solve the problem of difficult control of low-frequency noise in the compressor pipeline, and by applying different voltage values ​​to the piezoelectric film, the vibration frequency of the piezoelectric film can be actively changed, so as to be applied to the noise generated by the compressor under various different working conditions.

[0106] Second, the electrode sheet is constructed in a circular shape and attached to the center of the piezoelectric film to prevent the piezoelectric film from wrinkling in all directions and keep the piezoelectric film able to vibrate effectively in a noisy environment. The area of ​​the electrode sheet accounts for 15% to 25% of the area of ​​the piezoelectric film. The area of ​​the piezoelectric film occupied by the electrode sheet is within this range, so that the area of ​​the electrode sheet remains moderate. If it exceeds this range, the electrode sheet with a larger area affects the vibration of the piezoelectric film. If it is less than this range, the electrode sheet with a smaller area cannot prevent the piezoelectric film from wrinkling.

[0107] Third, the sound-absorbing material is set to be a porous fiber sound-absorbing material. When the sound wave encounters the porous sound-absorbing material, part of the sound wave will enter the pores of the material. When the sound wave propagates in the pores, it will cause the vibration of the air molecules in the pores. Due to the friction between the air molecules in the pores and the skeleton of the material, this friction will cause the sound energy to be converted into heat energy, which is absorbed by the material. The high-frequency sound wave has a shorter wavelength and is easy to be absorbed. The high-frequency noise is absorbed by designing the sound-absorbing material, while the low-frequency sound wave has a longer wavelength and is not easy to be absorbed. For low-frequency noise, by designing the piezoelectric film and the back cavity, the sound wave will generate a sound wave opposite to the noise sound wave when it acts on the piezoelectric film, forming an interference effect, thereby offsetting the noise sound wave, thereby actively reducing or eliminating the noise. At the same time, the vibration will transfer the noise energy to the back cavity while vibrating, and the sound wave energy will resonate in the back cavity and be further dissipated, so as to achieve a good noise reduction effect on both low-frequency and high-frequency noise.

[0108] Fourthly, a plurality of silencer units form a silencer device, and by controlling the vibration frequency of the piezoelectric film in each silencer unit, the silencer device has a wider silencer frequency range compared to a single silencer unit.

[0109] It is further understood that in the present disclosure, "plurality" refers to two or more than two, and other quantifiers are similar thereto. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. The singular forms "a", "the" and "the" are also intended to include plural forms, unless the context clearly indicates other meanings.

[0110] It is further understood that the terms "first", "second", etc. are used to describe various information, but such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other, and do not indicate a specific order or degree of importance. In fact, the expressions "first", "second", etc. can be used interchangeably. For example, without departing from the scope of the present disclosure, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information.

[0111] It is further understood that, although the operations are described in a specific order in the drawings in the embodiments of the present disclosure, it should not be understood as requiring the operations to be performed in the specific order shown or in a serial order, or requiring the execution of all the operations shown to obtain the desired results. In certain environments, multitasking and parallel processing may be advantageous.

[0112] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0113] It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the scope of the appended claims.

Claims

1. A sound-absorbing unit for absorbing the noise of a vibrating device, characterized in that: include: A shell (1), the shell (1) being formed with a back cavity (2), and one side of the shell (1) being formed with an opening communicating with the back cavity (2); A piezoelectric film (3), wherein the piezoelectric film (3) is attached to the opening; An electrode sheet (4), the electrode sheet (4) being constructed as a flexible sheet, the electrode sheet (4) being attached to the piezoelectric film (3) and electrically connected to the piezoelectric film (3), and the electrode sheet (4) being configured to be electrically connected to a power supply; The piezoelectric film (3) and the electrode sheet (4) are configured such that: the electrode sheet (4) can be controlled according to the frequency of the noise to provide a corresponding voltage value; The greater the voltage value supplied to the electrode sheet (4), the greater the stress generated by the piezoelectric film (3), and the lower the vibration frequency of the piezoelectric film (3).

2. The sound-absorbing unit according to claim 1, characterized in that: The electrode sheet (4) is constructed in a circular shape and is attached to the center of the piezoelectric film (3).

3. The sound-absorbing unit according to claim 2, characterized in that: The area of ​​the electrode sheet (4) accounts for 15% to 25% of the area of ​​the piezoelectric film (3).

4. The sound-absorbing unit according to claim 1, characterized in that: The piezoelectric film (3) and the back cavity (2) form a resonant sound absorber for actively absorbing low-frequency noise; A sound absorbing material (7) is arranged on the inner wall surface of the back cavity (2); the sound absorbing material (7) is a porous structure and is used for passively absorbing high-frequency noise.

5. The sound-absorbing unit according to any one of claims 1 to 4, characterized in that: The muffler unit also includes a controller (10); An acoustic sensor (6) is provided on the electrode sheet (4); The controller (10) is designed to control the voltage value supplied by the power supply to the electrode sheet (4) according to the noise signal detected by the acoustic sensor (6), thereby controlling the stress value of the piezoelectric film (3) so that the vibration frequency of the piezoelectric film (3) is regulated.

6. A muffler, characterized in that: include: One or more sound-absorbing units according to any one of claims 1 to 5; The voltage level of each electrode sheet (4) can be controlled independently to supply voltage.

7. The muffler device according to claim 6, characterized in that: A plurality of the shells (1) are connected together; The electrode sheet (4) of each of the noise-absorbing units is supplied with voltages of different values.

8. An air conditioner, characterized in that: The air conditioner comprises: a casing (8), wherein a compressor pipeline (11) is arranged in the casing (8); The air conditioner further comprises a silencer as claimed in claim 6 or 7, wherein the silencer is arranged in the casing (8) and the piezoelectric film (3) in the silencer faces the compressor pipeline (11).

9. The air conditioner according to claim 8, characterized in that: The air conditioner includes an outdoor unit, the outdoor unit includes the casing (8), the casing (8) includes a top plate (801), a panel (802), a right side plate (803), a partition (9), and a base (804), the top plate (801), the panel (802), the right side plate (803), the partition (9), and the base (804) forming a closed space, the silencer device is embedded in the partition (9), and the partition (9) is close to the compressor pipeline (11).

10. A noise reduction method for the air conditioner according to any one of claims 8 to 9, characterized in that: Obtain the noise frequency signal during air conditioning operation; Performing frequency identification on the noise frequency signal; The voltage supplied to the electrode sheet (4) is controlled according to the recognition result, the stress on the piezoelectric film (3) is changed, and the noise frequency is regulated.

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