A noise elimination unit, a noise elimination device, an air conditioner and a noise reduction method of air conditioner

Abstract

The application belongs to the technical field of air conditioners, and discloses a sound elimination unit, a sound elimination device, an air conditioner and an air conditioner noise reduction method. The sound elimination unit comprises a shell, a piezoelectric film and an electrode sheet. The voltage on the electrode sheet is controlled, the voltage of the piezoelectric film is controlled, the stress on the surface of the piezoelectric film is changed, the vibration frequency of the piezoelectric film is finally changed, the active control of the sound elimination frequency of the piezoelectric film is realized, and the noise of a specific frequency band can be more targetedly eliminated. The sound elimination unit is applied to an air conditioner outdoor unit, the noise generated by a compressor pipeline can be effectively eliminated, the problem of low-frequency noise control of the compressor pipeline can be solved, different voltage values are applied to the piezoelectric film, the vibration frequency of the piezoelectric film can be actively changed, and the noise generated by the compressor under various working conditions can be applied.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a noise reduction unit, a noise reduction device, an air conditioner, and a noise reduction method for air conditioning. Background Technology

[0002] Currently, in air conditioning technologies, especially in outdoor units, the compressor, as the main working component, generates vibration and noise during operation. This vibration and noise is transmitted along the pipes and casing to the entire outdoor unit structure. When the compressor's operating frequency approaches the pipe modal frequency, severe vibration and noise problems occur. The pipe vibration can cause deformation of the outdoor unit structure, reducing the overall reliability of the outdoor unit. Therefore, controlling the vibration and noise of the compressor pipes is essential.

[0003] Common methods for reducing pipeline vibration and noise in existing technologies include increasing pipeline counterweights to lower pipeline modal frequencies, thus offsetting the compressor excitation frequency from the pipeline resonant frequency to avoid resonance. While increasing counterweights can solve some vibration and noise problems, it may cause resonance at other pipeline frequencies, resulting in low reliability and limited effectiveness. Another method is to add damping materials to the pipeline to dissipate vibration energy. However, in actual use, vibration-damping rubber pads may harden and lose their damping effect due to long-term exposure to the external environment, leading to breakage of elastic molecular chains, destruction of cross-linked structures, or material aging. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing noise reduction methods are not effective. Therefore, the present invention provides a noise reduction unit, a noise reduction device, an air conditioner and a noise reduction method for air conditioners.

[0005] This invention aims to provide a noise reduction unit for absorbing noise from vibrating equipment, comprising:

[0006] A housing having a back cavity, and an opening communicating with the back cavity being formed on one side of the housing;

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

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

[0009] The piezoelectric film and the electrode sheet are configured such that the electrode sheet can be controlled according to the noise frequency and supplied with a corresponding voltage value; the higher 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 configured to be circular and 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 disposed on the inner wall of the back cavity, and the sound-absorbing material has a porous structure for passively absorbing high-frequency noise.

[0013] In some embodiments, the silencing unit further includes a controller;

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

[0015] The controller is designed to control the voltage value supplied by the power supply to the electrode plate 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 noise reduction units;

[0018] The voltage of each electrode can be individually controlled by the supply voltage.

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

[0020] The electrode plates of each of the silencing units are supplied with a different voltage value.

[0021] In some embodiments, an air conditioner is provided, the air conditioner including: a housing, wherein a compressor pipeline is disposed inside the housing;

[0022] The air conditioner also includes the aforementioned silencing device, which is disposed inside the housing and the piezoelectric diaphragm in the silencing device faces the compressor piping.

[0023] In some embodiments, the air conditioner includes an outdoor unit, the outdoor unit includes the housing, the housing includes a top plate, a front panel, a right side panel, a partition, and a base, the top plate, the front panel, the right side panel, the partition, and the base form a closed space, the silencing device is embedded inside the partition, and the partition is close to the compressor piping.

[0024] In some embodiments, a method for reducing noise in an air conditioner as described above is provided.

[0025] Acquire noise frequency signals during air conditioner operation;

[0026] Frequency identification is performed on the noise frequency signal;

[0027] Based on the identification results, the voltage supplied to the electrode sheet is controlled to change the stress on the piezoelectric film, thereby achieving noise frequency regulation.

[0028] The technical solution provided by this invention has the following advantages compared with the prior art:

[0029] In silencing units, by controlling the current on the electrode plates, and consequently the voltage on the electrode plates, the voltage generated by the current flowing through the electrode plates is controlled. This alters the stress on the surface of the piezoelectric film, ultimately changing its vibration frequency. This allows for active control of the silencing frequency of the piezoelectric film, ensuring its vibration frequency is close to or equal to the noise frequency, thus more effectively eliminating noise in specific frequency bands. Applying silencing units to air conditioner outdoor units can effectively eliminate noise generated by the compressor piping, particularly addressing the difficulty of controlling low-frequency noise in compressor piping. Furthermore, by applying different voltage values ​​to the piezoelectric film, its vibration frequency can be actively changed, thus addressing noise generated under various compressor operating conditions. Attached Figure Description

[0030] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0031] Figure 1 This is a schematic diagram of the sound-absorbing unit structure shown in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the noise reduction device shown in an embodiment of the present invention;

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

[0034] Figure 4 This is one of the schematic diagrams of an air conditioner shown in the embodiments of the present invention;

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

[0036] Figure 6 This is a flowchart illustrating an air conditioning noise reduction method according to an embodiment of the present invention;

[0037] In the diagram: 1-Housing, 2-Back cavity, 3-Piezoelectric film, 4-Electrode sheet, 401-Electrical connection terminal, 5-Electrical wire, 6-Acoustic sensor, 7-Sound absorbing material, 8-Casing, 801-Top plate, 802-Face panel, 803-Side plate, 804-Base, 9-Block, 10-Controller, 11-Compressor piping.

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

[0039] In the description of this invention, it should be noted that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "contact," and "communication" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] Common methods for reducing pipeline vibration and noise in existing technologies include increasing pipeline counterweights to lower pipeline modal frequencies, thus offsetting the compressor excitation frequency from the pipeline resonant frequency to avoid resonance. While increasing counterweights can solve some vibration and noise problems, it may cause resonance at other pipeline frequencies, resulting in low reliability and limited effectiveness. Another method is to add damping materials to the pipeline to dissipate vibration energy. However, in actual use, vibration-damping rubber pads may harden and lose their damping effect due to long-term exposure to the external environment, leading to breakage of elastic molecular chains, destruction of cross-linked structures, or material aging.

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

[0043] Example 1

[0044] like Figure 1 As shown, this embodiment proposes a noise reduction unit for absorbing noise from vibrating equipment, comprising:

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

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

[0047] Electrode 4 is constructed as a flexible sheet. Electrode 4 is attached to and electrically connected to piezoelectric film 3. Electrode 4 is configured to be electrically connected to power supply.

[0048] The piezoelectric film 3 and the electrode sheet 4 are configured such that the electrode sheet 4 can be controlled according to the noise frequency and supplied with a corresponding voltage value; the higher 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 is a DE piezoelectric film, which is a novel electroactive material with fast response and large deformation caused by applied voltage. The electrode sheet 4 is made of flexible conductive electrode material. The electrode sheet 4 is electrically connected to the controller 10 through the wire 5. By acquiring the noise frequency in the external environment, the controller 10 can control the current on the electrode sheet 4 according to the noise frequency, thereby controlling the voltage on the electrode sheet 4, and thus controlling 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. This achieves active control of the noise reduction 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 more effectively eliminate noise in specific frequency bands.

[0050] When noise from the external environment is transmitted to the noise-absorbing unit, the piezoelectric film 3, when subjected to sound waves, undergoes minute deformation, resulting in a voltage on its surface. Applying voltage to the piezoelectric film 3 via the electrode plate 4 causes it to vibrate in the opposite direction. This vibration generates sound waves that are opposite in phase to the incident sound waves, creating an interference effect. When these two sound waves meet, they cancel each other out, thus actively reducing or eliminating noise. Simultaneously, the piezoelectric film 3 transmits noise to the back cavity 2, where the sound wave energy resonates and is further dissipated, achieving a better noise reduction effect.

[0051] The flexible electrode material can be a carbon resin material. When power is supplied to the flexible electrode, it acts 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 long sound waves that is not easily absorbed. The relationship between the stress on the surface of the piezoelectric film 3 and the voltage is as follows:

[0052] V = dF / C;

[0053] Where V represents the surface voltage generated by the piezoelectric film 3; d is the piezoelectric constant, which describes the material's ability to generate charge and is related to the material's properties; F is the preload force, i.e., stress, experienced by the piezoelectric film; and C is the capacitance, which is related to the size and thickness of the piezoelectric film 3.

[0054] Applying this noise reduction unit to the outdoor unit of an air conditioner can effectively eliminate the noise generated by the compressor pipeline. In particular, it can address the problem of difficulty in controlling low-frequency noise in the compressor pipeline. Furthermore, by applying different voltage values ​​to the piezoelectric film 3, the vibration frequency of the piezoelectric film 3 can be actively changed, thereby addressing the noise generated by the compressor under various operating conditions.

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

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

[0057] In this embodiment, the electrode sheet 4 is constructed in a circular shape and is attached to the center of the piezoelectric film 3 to prevent the piezoelectric film 3 from wrinkling in all directions, thus ensuring that the piezoelectric film 3 can vibrate effectively 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. Within this range, the area of ​​the electrode sheet 4 is kept moderate. If it exceeds this range, the larger area of ​​the electrode sheet 4 will affect the vibration of the piezoelectric film 3. If it is smaller than this range, the smaller area of ​​the electrode sheet 4 will not be able to prevent the piezoelectric film 3 from wrinkling.

[0059] Optionally, in one implementation of this embodiment, such 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] The inner wall of the back cavity 2 is provided with sound-absorbing material 7, which has a porous structure and is used to passively absorb 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, used to absorb high-frequency noise. When sound waves encounter the porous sound-absorbing material, some sound waves will enter the pores of the material. When the sound waves propagate in the pores, they will cause the air molecules in the pores to vibrate. Due to the friction between the air molecules in the pores and the material skeleton, this friction will cause the sound energy to be converted into heat energy, which will be absorbed by the material. High-frequency sound waves have lower wavelengths and are easily absorbed. High-frequency noise is absorbed by designing the sound-absorbing material 7, while low-frequency sound waves have longer wavelengths and are not easily absorbed. For low-frequency noise, the piezoelectric film 3 is designed to cooperate with the back cavity 2. When the sound waves act on the piezoelectric film 3, they will interact with the piezoelectric film 3. The vibration of the piezoelectric film 3 dissipates some 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 will resonate in the back cavity 2 and be further dissipated. The controller 10 makes the vibration frequency of the piezoelectric film 3 close to or equal to the noise frequency, so as to more effectively eliminate low-frequency noise.

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

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

[0065] The noise reduction unit also includes a controller 10;

[0066] An acoustic sensor 6 is mounted on the electrode plate 4;

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

[0068] In this embodiment, the two ends of the electrode plate 4 form electrical connection terminals 401. An electrical conductor 5 is provided on the housing 1. One end of the electrical conductor 5 is electrically connected to the electrical connection terminal 401 to form an electrical connection between the electrode plate 4 and the piezoelectric film 3, and the other end is electrically connected to the controller. There are two electrical connection terminals 401, both of which are strip-shaped structures located on both sides of the electrode plate 4. They are electrically connected to the electrical conductor 5 to form a closed circuit. The acoustic sensor 6 is used to detect noise signals and transmit them to the controller 10. The controller 10 supplies power to the electrode plate 4 through the electrical conductor 5 based on the noise signal. This power acts on the surface of the piezoelectric film 3. When the piezoelectric film 3 is subjected to a DC voltage, it can resonate with the back cavity 2 at a low frequency, thereby suppressing low-frequency noise. The conductor 5 can be arranged inside the back cavity 2 and extend out through the upper part of the back cavity 2 to connect with the controller 10. The controller 10 can control the current on the electrode plate 4 according to the noise frequency, thereby controlling the voltage on the electrode plate 4, and then controlling 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, realizing active control of the noise reduction 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 more effectively eliminate noise in specific frequency bands.

[0069] Example 2

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

[0071] One or more noise reduction units from Embodiment 1;

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

[0073] Specifically, multiple housings 1 are connected together;

[0074] Each silencing unit's electrode plate 4 is supplied with a different voltage value.

[0075] In this embodiment, multiple housings 1 are constructed as a single unit. When the silencing device consists of multiple silencing units, by controlling the voltage of the electrode plates 4 in each silencing unit at different values, the vibration frequency of the piezoelectric film 3 is made different. Compared with a single silencing unit, the silencing device has a wider silencing frequency range.

[0076] Example 3

[0077] In this embodiment, as Figure 4 , 5 As shown, an air conditioner is provided, which includes: a housing 8, and a compressor pipeline 11 is disposed inside the housing 8;

[0078] The air conditioner also includes the silencing device in Embodiment 2, which is disposed inside the housing 8 and the piezoelectric diaphragm 3 in the silencing device faces the compressor pipeline 11.

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

[0080] In this embodiment, the silencing device is positioned at the partition 9 with the piezoelectric film 3 in the silencing device facing the compressor pipeline 11. This position minimizes the distance between the silencing device and the compressor pipeline 11. The silencing device can eliminate both low-frequency and high-frequency noise from the compressor pipeline 11 through a combination of active and passive methods. Figure 4 As shown, the housing 8 has a top plate 801, a front panel 802, a side panel 803, and a base 804. The top plate 801, front panel 802, side panel 803, and base 804 together form a relatively enclosed housing 8, as shown. Figure 5 As shown, the controller 10 is electrically connected to the silencing device via the wire 5. The silencing device suppresses the vibration noise of the compressor pipeline 11 inside the housing 8.

[0081] The acoustic sensor 6 detects the ambient noise signal and transmits it to the controller 10. After receiving the electrical signal, the controller 10 can control the voltage on the electrode plate 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 ultimately changing the vibration frequency of the piezoelectric film 3. This achieves active control of the noise reduction 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, thus more effectively eliminating noise in specific frequency bands.

[0082] When noise from the external environment is transmitted to the noise-absorbing unit, the piezoelectric film 3, when subjected to sound waves, undergoes minute deformation, resulting in a voltage on its surface. Applying voltage to the piezoelectric film 3 via the electrode plate 4 causes it to vibrate in the opposite direction. This vibration generates sound waves that are opposite in phase to the incident sound waves, creating an interference effect. When these two sound waves meet, they cancel each other out, thus actively reducing or eliminating noise. Simultaneously, the piezoelectric film 3 transmits noise to the back cavity 2, where the sound wave energy resonates and is further dissipated, achieving a better noise reduction effect. The controller 10 makes the vibration frequency of the piezoelectric film 3 close to or equal to the noise frequency, thus more effectively eliminating low-frequency noise. When sound waves encounter porous sound-absorbing materials, some sound waves will enter the pores of the material. When the sound waves propagate in the pores, they will cause the air molecules in the pores to vibrate. Due to the friction between the air molecules in the pores and the material skeleton, this friction will cause the sound energy to be converted into heat energy, which will be absorbed by the material. High-frequency sound waves have lower wavelengths and are more easily absorbed. High-frequency noise is eliminated by designing the sound-absorbing material 7, and low-frequency noise is eliminated by designing the piezoelectric film 3 to cooperate with the back cavity 2. Thus, the silencer can comprehensively suppress the vibration noise of the compressor pipeline 11 in the housing 8.

[0083] The silencer consists of multiple silencer units and has a wider silencer frequency range, making it suitable for various operating conditions of the compressor.

[0084] Example 4

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

[0086] Acquire noise frequency signals during air conditioner operation;

[0087] Frequency identification of noise frequency signals;

[0088] Based on the identification results, the voltage supplied to the electrode sheet 4 is controlled to change the stress on the piezoelectric film 3, thereby achieving noise frequency regulation.

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

[0090] When the acoustic sensor 6 detects a noise frequency signal that is multi-band, the controller 10 receives an electrical signal and identifies the frequency. Based on the identification result, it controls the voltage value of each piezoelectric film 3 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 machine learning capabilities to control the voltage corresponding to the piezoelectric film 3 and the stress it experiences under the corresponding voltage, so as to improve the noise reduction performance and frequency control capability of the piezoelectric silencing device.

[0092] This learning process addresses the issue of silencing frequency control through the following steps:

[0093] (1) Optimization of noise reduction performance

[0094] The noise reduction performance of the silencer is analyzed and calculated based on the size of the back cavity 2 and the preload of the piezoelectric film 3. The noise reduction performance of the silencer under different preload parameters of the piezoelectric film 3 is obtained in order to evaluate and optimize the performance of the silencer.

[0095] (2) Parameter tuning

[0096] By combining particle swarm optimization (PSO) with analytical prediction models (PSO), optimization calculations are performed to determine the required preload force for each piezoelectric film 3 at different frequencies, thereby optimizing the preload force of the piezoelectric film to achieve the best noise reduction performance. Different preload forces and back cavity designs affect the noise reduction frequency and effect; therefore, it is necessary to determine the optimal parameters through calculation to achieve the best noise reduction effect. This process determines the required preload force of the piezoelectric film 3 at different frequencies, thus enabling the noise reduction device to achieve the best noise reduction effect at specific frequencies.

[0097] (3) Voltage calculation

[0098] Based on the inherent parameter characteristics of the piezoelectric film 3, the required voltage for the piezoelectric film 3 under different preload forces is calculated. This process ensures that the piezoelectric film can operate at an appropriate voltage in practical applications, thereby achieving effective acoustic wave control.

[0099] (4) Controller input

[0100] The calculated voltage of the piezoelectric film 3 and the noise reduction and energy absorption algorithm curve are input into the electrical controller 10, thereby completing the learning process to control the noise reduction frequency of the noise reduction device. This process ensures that the noise reduction device can flexibly adjust its operating 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 reduction and energy absorption algorithm curve of the noise reduction device are input into the controller 10 to complete the learning process of noise reduction frequency control of the noise reduction device.

[0102] The learning process aims to solve the problem of noise reduction frequency control of the noise reduction device made of piezo-acoustic metamaterial, 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 is necessary to specify here that the preload referred to in this application is the initial stress.

[0104] In summary, the ingenious design of the noise reduction unit lies in:

[0105] Firstly, in the silencing unit, by controlling the current on the electrode plates, and thus the voltage on the electrode plates, the voltage applied to the piezoelectric film is controlled. This alters the stress on the surface of the piezoelectric film, ultimately changing its vibration frequency. This allows for active control of the silencing frequency of the piezoelectric film, making its vibration frequency close to or equal to the noise frequency, thus more effectively eliminating noise in specific frequency bands. Applying this silencing unit to air conditioner outdoor units can effectively eliminate noise generated by the compressor piping, particularly addressing the difficulty of controlling low-frequency noise in compressor piping. Furthermore, by applying different voltage values ​​to the piezoelectric film, its vibration frequency can be actively changed, thus adapting to noise generated under various compressor operating conditions.

[0106] Secondly, constructing the electrode sheet in a circular shape and attaching it to the center of the piezoelectric film can prevent wrinkling of the piezoelectric film from all directions, ensuring that the piezoelectric film can vibrate effectively in noisy environments. The area of ​​the electrode sheet occupies 15% to 25% of the area of ​​the piezoelectric film. Within this range, the area of ​​the electrode sheet is kept moderate. If it exceeds this range, the larger area of ​​the electrode sheet will affect the vibration of the piezoelectric film; if it is smaller than this range, the smaller area of ​​the electrode sheet will not be able to prevent wrinkling of the piezoelectric film.

[0107] Third, the sound-absorbing material is set as a porous fiber sound-absorbing material. When sound waves encounter the porous sound-absorbing material, some of the sound waves will enter the pores of the material. When the sound waves propagate in the pores, they will cause the air molecules in the pores to vibrate. Due to the friction between the air molecules in the pores and the material skeleton, this friction will cause the sound energy to be converted into heat energy, which will be absorbed by the material. High-frequency sound waves have lower wavelengths and are more easily absorbed. By designing the sound-absorbing material, high-frequency noise can be absorbed. Low-frequency sound waves have longer wavelengths and are not easily absorbed. For low-frequency noise, by designing a piezoelectric film to cooperate with the back cavity, when the sound wave acts on the piezoelectric film, it will generate a sound wave opposite to the noise sound wave, forming an interference effect, thereby canceling the noise sound wave, thus actively reducing or eliminating the noise. At the same time, the vibration will transfer the noise energy to the back cavity. The sound wave energy will resonate in the back cavity and be further dissipated, achieving a good noise reduction effect for both low-frequency and high-frequency bands.

[0108] Fourth, a silencing device is composed of multiple silencing units. By controlling the vibration frequency of the piezoelectric film in each silencing unit, the silencing device has a wider silencing frequency range compared to a single silencing unit.

[0109] It can be further understood that in this disclosure, "multiple" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

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

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

[0112] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

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

Claims

1. A noise-absorbing unit for absorbing noise from vibrating equipment, characterized in that, include: A housing (1) having a back cavity (2) and an opening communicating with the back cavity (2) on one side of the housing (1); A piezoelectric film (3) is attached to the opening; Electrode sheet (4), the electrode sheet (4) is constructed as a flexible sheet, the electrode sheet (4) is attached to the piezoelectric film (3) and electrically connected to the piezoelectric film (3), the electrode sheet (4) is attached to the center position of the piezoelectric film (3), and the electrode sheet (4) is configured to be electrically connected to the 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 noise frequency to provide a corresponding voltage value; The greater the voltage supplied to the electrode plate (4), the greater the stress generated by the piezoelectric film (3), and the lower the vibration frequency of the piezoelectric film (3). The voltage supplied to the electrode plate (4) can cause the piezoelectric film (3) to generate a reverse sound wave that is opposite in phase to the noise sound wave through vibration, and the reverse sound wave and the noise sound wave form an interference effect.

2. The noise reduction unit as described in claim 1, characterized in that, The electrode sheet (4) is constructed in a circular shape.

3. The noise reduction unit as described in 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 noise reduction unit as described in 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; The inner wall of the back cavity (2) is provided with a sound-absorbing material (7), which has a porous structure and is used to passively absorb high-frequency noise.

5. The noise reduction unit as described in any one of claims 1-4, characterized in that, The silencing 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 plate (4) according to the noise signal detected by the acoustic sensor (6), thereby controlling the stress value of the piezoelectric film (3) and regulating the vibration frequency of the piezoelectric film (3).

6. A noise reduction device, characterized in that, include: One or more sound-absorbing unit components as described in any one of claims 1-5; The voltage of each electrode (4) can be individually controlled by the supply voltage.

7. The silencing device according to claim 6, characterized in that, Multiple housings (1) are connected together; The electrode plate (4) of each of the silencing units is supplied with a voltage of a different value.

8. An air conditioner, characterized in that, The air conditioner includes: a housing (8), and a compressor pipeline (11) is provided inside the housing (8); The air conditioner also includes a silencing device as described in claim 6 or 7, the silencing device being disposed within the housing (8) and the piezoelectric film (3) in the silencing device facing the compressor piping (11).

9. The air conditioner as described in claim 8, characterized in that, The air conditioner includes an outdoor unit, which includes the casing (8). The casing (8) includes a top plate (801), a front panel (802), a right side panel (803), a partition (9), and a base (804). The top plate (801), the front panel (802), the right side panel (803), the partition (9), and the base (804) form a closed space. The sound-absorbing device is embedded inside the partition (9), which is close to the compressor pipeline (11).

10. A noise reduction method for an air conditioner according to any one of claims 8-9, characterized in that: Acquire noise frequency signals during air conditioner operation; Frequency identification is performed on the noise frequency signal; Based on the identification results, the voltage supplied to the electrode sheet (4) is controlled to change the stress on the piezoelectric film (3) and thus achieve noise frequency regulation.

Images