Parallel Helmholtz resonant cavity with adjustable sound absorption performance

Abstract

The invention relates to a parallel Helmholtz resonant cavity with adjustable sound absorption performance, and the resonant cavity comprises a main body cavity which is internally provided with a plurality of sound absorption cavities in parallel, and the top surface of each sound absorption cavity is provided with a first sound absorption hole and a second sound absorption hole at an interval along a first direction; the upper cover plate is slidably connected with the main body cavity in the first direction, a plurality of communicating areas are arranged on the upper cover plate, and a plurality of third sound absorption holes and fourth sound absorption holes are formed in each communicating area at intervals in the first direction; the plurality of sound absorption cavities and the plurality of communication areas are arranged in a one-to-one correspondence manner; the PVC gel drivers are connected with the upper cover plate, the corresponding first sound absorption holes and the corresponding third sound absorption holes are overlapped and communicated when the PVC gel drivers are not powered on, and the PVC gel drivers contract when the PVC gel drivers are powered on so that the corresponding second sound absorption holes and the corresponding fourth sound absorption holes can be overlapped and communicated. Through the design of the parallel sound absorption cavities, low-frequency broadband sound absorption with multiple sound absorption peaks is generated, and further, the low-frequency broadband sound absorption effect aiming at different frequencies is achieved on the premise that the size parameters and the structures of the sound absorption cavities are not changed.

Description

Technical Field

[0001] The invention belongs to the technical field of noise control, and in particular relates to a parallel Helmholtz resonance cavity with adjustable sound absorption performance. Background Art

[0002] With the rapid development of industrial level and economy, the impact of low-frequency noise on people's production and life is gradually increasing. Low-frequency noise control is also one of the bottleneck technologies for improving the performance of mechanical equipment such as ships / underwater vehicles, aerospace, high-speed trains and precision machine tools. The use of traditional porous sound-absorbing materials (such as sound-absorbing felt and sound-absorbing cotton) requires a large volume and mass to achieve the corresponding low-frequency sound absorption effect. Under the constraints of limited space and strict quality conditions, it is difficult to achieve the noise reduction requirements of high sound absorption coefficients, which seriously restricts the engineering application of traditional porous sound-absorbing materials.

[0003] The Helmholtz resonant cavity consists of a sealed cavity and a circular long neck connected to the outside world. Its dimensional parameters include: the length, width and height of the sealed cavity, the length and cross-sectional area of ​​the long neck. When the sound wave is incident vertically on the surface of the resonant cavity, the cavity of the resonant cavity and the air column in the long neck form a spring-mass system. The frequency of the incident sound wave is close to the natural frequency of the resonant cavity. The system enters a resonant state, and the air column in the long neck vibrates violently. Due to the friction resistance and other damping effects in the system, the vibration energy of the air column is released in the form of heat energy, completing the absorption of the sound wave energy. Sound-absorbing devices based on the Helmholtz resonant cavity often have a thinner appearance and smaller size, which has greater advantages in application scenarios with limited space.

[0004] By changing the size parameters and structure of the Helmholtz resonant cavity, sound absorption of different frequencies can be achieved. In the case of low-frequency broadband sound absorption, the depth and number of sealed cavities used for sound absorption need to be increased, but this is difficult to achieve in some cases where space is limited. In addition, once the size parameters of the Helmholtz cavity are determined, its sound absorption coefficient curve is also determined and can no longer change with changes in the excitation frequency and environmental conditions, making it difficult to flexibly adjust the sound absorption effect according to the corresponding frequency band.

[0005] Therefore, there is a need for a sound-absorbing structure with adjustable frequency, which can be adjusted in real time according to the needs of the application scenario and can achieve low-frequency broadband sound absorption effects for different frequencies when the size parameters and structure of the sound-absorbing cavity are small. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a parallel Helmholtz resonant cavity with adjustable sound absorption performance. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] The present invention provides a parallel Helmholtz resonance cavity with adjustable sound absorption performance, comprising: a main body cavity, in which a plurality of sound absorption chambers are arranged in parallel, and a first sound absorption hole and a second sound absorption hole are arranged at intervals on the top surface of each of the sound absorption chambers along a first direction; an upper cover plate, which covers the top surfaces of the plurality of sound absorption chambers and is slidably connected to the main body cavity along the first direction; the upper cover plate is provided with a plurality of connecting areas, and a third sound absorption hole and a fourth sound absorption hole are arranged at intervals along the first direction on each of the connecting areas; the plurality of sound absorption chambers are arranged in one-to-one correspondence with the plurality of connecting areas, and the diameters of the corresponding first sound absorption hole and the third sound absorption hole are equal, and the diameters of the corresponding second sound absorption hole and the fourth sound absorption hole are equal; a PVC gel driver, which is connected to the upper cover plate, and when the PVC gel driver is not powered on, the corresponding first sound absorption hole and the third sound absorption hole are overlapped and connected, and when the PVC gel driver is powered on, the PVC gel driver contracts so that the corresponding second sound absorption hole and the fourth sound absorption hole overlap and connect.

[0008] In one embodiment of the present invention, an inverted L-shaped slide groove is provided on two opposite sides of the top of the main body cavity along the second direction, and the two ends of the upper cover plate are slidably connected to the inverted L-shaped slide groove; wherein the first direction and the second direction are perpendicular to each other.

[0009] In one embodiment of the present invention, stoppers are provided on two opposite sides of the top of the main body cavity along the first direction.

[0010] In one embodiment of the present invention, the diameters of the first sound absorption hole and the second sound absorption hole located in the same sound absorption chamber are not equal; the diameters of the third sound absorption hole and the fourth sound absorption hole located in the same connecting area are not equal.

[0011] In one embodiment of the present invention, a rectangular groove is arranged on the top of one side of the main body cavity, and the length direction of the rectangular groove is arranged along the first direction.

[0012] In one embodiment of the present invention, a driver placement cavity is provided in the main body cavity, the PVC gel driver is arranged in the driver placement cavity, and the rectangular groove is located at the top of the driver placement cavity.

[0013] In one embodiment of the present invention, the PVC gel driver comprises: a plurality of groups of PVC gel laminated drive units, each group of the PVC gel laminated drive units comprises: a plurality of layers of anode metal mesh, PVC gel film and cathode conductive sheet stacked in sequence.

[0014] In one embodiment of the present invention, the parallel Helmholtz resonance cavity with adjustable sound absorption performance also includes: a driver connection block, the driver connection block is L-shaped, the first end of the driver connection block is connected to the PVC gel driver, and the second end of the PVC gel driver is connected to the upper cover plate.

[0015] In one embodiment of the present invention, a protrusion is provided at the second end of the driver connecting block, and the protrusion is located in the rectangular groove and connected to the bottom surface of the upper cover plate.

[0016] In one embodiment of the present invention, the parallel Helmholtz resonance cavity with adjustable sound absorption performance further includes: a driver side panel, the driver side panel is detachably connected to the driver placement cavity, and a wire outlet groove is provided in the middle of the driver side panel.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The Helmholtz resonance cavity with adjustable sound absorption performance of the present invention generates multiple sound absorption peaks through the design of parallel sound absorption chambers, has the advantage of compact structure, and can achieve broadband sound absorption effect. At the same time, without changing the size parameters and structure of the sound absorption chamber, the energized contraction characteristics of the PVC gel driver and the mutual cooperation of the sound absorption holes are used to achieve the aperture change of the overlapping and connected sound absorption holes. The sound absorption frequency can be adjusted in real time according to the needs of the application scenario to achieve low-frequency broadband sound absorption effects for different frequencies.

[0019] The Helmholtz resonance cavity with adjustable sound absorption performance of the present invention uses voltage as a control signal to control the PVC gel driver. Compared with the traditional adjustment method based on mechanical component drive and based on changing size parameters or structural adjustment, it has a smaller structure and is easier to operate, which is more conducive to the lightweight and compactness of the overall structure and has broad application prospects.

[0020] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a parallel Helmholtz resonance cavity with adjustable sound absorption performance provided by an embodiment of the present invention;

[0022] Figure 2 is a cross-sectional view of the structure of a parallel Helmholtz resonance cavity with adjustable sound absorption performance provided by an embodiment of the present invention;

[0023] Figure 3is a schematic structural diagram of a main body cavity provided by an embodiment of the present invention;

[0024] Figure 4 is a structural cross-sectional view of the main body cavity provided by an embodiment of the present invention;

[0025] Figure 5 is a schematic structural diagram of an upper cover plate provided by an embodiment of the present invention;

[0026] Figure 6a is a schematic diagram of the structure of a PVC gel driver provided by an embodiment of the present invention;

[0027] Figure 6b It is a schematic structural diagram of a PVC gel laminated driving unit provided by an embodiment of the present invention;

[0028] Figure 7 is a schematic structural diagram of a driver connection block provided by an embodiment of the present invention;

[0029] Figure 8 It is a structural schematic diagram of an upper cover plate, a driver connecting block and a PVC gel driver provided in an embodiment of the present invention;

[0030] Fig. 9 is a schematic structural diagram of a driver side plate provided by an embodiment of the present invention;

[0031] Fig.10 is a schematic diagram of the state of the upper cover plate when no power is supplied according to an embodiment of the present invention;

[0032] Fig.11 is a schematic diagram of the state of the upper cover plate when powered on provided by an embodiment of the present invention;

[0033] Fig.12 It is a simulation result diagram of a parallel Helmholtz resonance cavity with adjustable sound absorption performance provided by an embodiment of the present invention.

[0034] Icons: 1-main body cavity; 11-inverted L-shaped slide groove; 12-sound absorption chamber; 121-first sound absorption hole; 122-second sound absorption hole; 13-rectangular groove; 14-driver placement cavity; 2-upper cover plate; 21-third sound absorption hole; 22-fourth sound absorption hole; 3-PVC gel driver; 31-anode metal mesh; 32-PVC gel film; 33-cathode conductive sheet; 4-driver connection block; 41-bump; 5-driver side panel; 51-wire outlet slot. DETAILED DESCRIPTION

[0035] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, a parallel Helmholtz resonance cavity with adjustable sound absorption performance proposed by the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0036] The above and other technical contents, features and effects of the present invention are clearly presented in the following detailed description of the specific implementation modes in conjunction with the accompanying drawings. Through the description of the specific implementation modes, the technical means and effects adopted by the present invention to achieve the predetermined purpose can be more deeply and specifically understood. However, the attached drawings are only for reference and explanation purposes and are not used to limit the technical solutions of the present invention.

[0037] Embodiment 1

[0038] In order to achieve the purpose of noise reduction in a small space, while not changing the size parameters and structure of the sound absorption chamber, such as not increasing the back cavity depth of the sound absorption chamber and the number of sound absorption chambers, to achieve a low-frequency broadband sound absorption effect, this embodiment provides a parallel Helmholtz resonance cavity with adjustable sound absorption performance, such as Figures 1 to 5 As shown, Figure 1 It is a schematic structural diagram of a parallel Helmholtz resonance cavity with adjustable sound absorption performance provided by an embodiment of the present invention; Figure 2 is a cross-sectional view of the structure of a parallel Helmholtz resonance cavity with adjustable sound absorption performance provided by an embodiment of the present invention; Figure 3 is a schematic structural diagram of a main body cavity provided by an embodiment of the present invention; Figure 4 is a structural cross-sectional view of the main body cavity provided by an embodiment of the present invention; Figure 5 It is a schematic structural diagram of an upper cover plate provided in an embodiment of the present invention.

[0039] In this embodiment, the parallel Helmholtz resonance cavity with adjustable sound absorption performance includes: a main body cavity 1, in which a plurality of sound absorption chambers 12 are arranged in parallel, and the top surface of each sound absorption chamber 12 is provided with a first sound absorption hole 121 and a second sound absorption hole 122 at intervals along a first direction; an upper cover plate 2, which covers the top surfaces of the plurality of sound absorption chambers 12 and is slidably connected to the main body cavity 1 along the first direction; the upper cover plate 2 is provided with a plurality of connecting areas, and each connecting area is provided with a third sound absorption hole 21 and a fourth sound absorption hole at intervals along the first direction 22; a plurality of sound absorption chambers 12 are arranged in one-to-one correspondence with a plurality of connecting areas, the diameters of the corresponding first sound absorption holes 121 and the third sound absorption holes 21 are equal, and the diameters of the corresponding second sound absorption holes 122 and the fourth sound absorption holes 22 are equal; a PVC gel driver 3 is connected to the upper cover plate 2, when the PVC gel driver 3 is not powered on, the corresponding first sound absorption holes 121 and the third sound absorption holes 21 are overlapped and connected, and when the PVC gel driver 3 is powered on, it contracts so that the corresponding second sound absorption holes 122 and the fourth sound absorption holes 22 are overlapped and connected.

[0040] The principle is that a plurality of sound absorption holes are provided on the upper cover plate 2 and the plurality of sound absorption chambers 12. When the corresponding sound absorption holes are connected, the sound absorption effect of a specific frequency can be achieved. When the aperture changes, the corresponding sound absorption frequency also changes. Therefore, by utilizing the power-on contraction characteristics of the PVC gel driver 3 and the mutual cooperation of the sound absorption holes, the conversion sound absorption of two different frequency bands can be achieved.

[0041] like Figure 6a and Figure 6b As shown, Figure 6a is a schematic diagram of the structure of a PVC gel driver provided by an embodiment of the present invention; Figure 6b It is a schematic structural diagram of a PVC gel laminated driving unit provided in an embodiment of the present invention.

[0042] Exemplarily, the PVC gel driver 3 is a "sandwich structure" including: a plurality of groups of PVC gel laminated driving units, each group of PVC gel laminated driving units includes: a plurality of layers of anode metal mesh 31, PVC gel film 32 and cathode conductive sheet 33 stacked in sequence.

[0043] The principle is that polyvinyl chloride gel (PVC gel) is a new type of electronic electroactive polymer material with the advantages of light weight, high transparency, large strain stress, wide working frequency band and fast response speed. The PVC gel driver 3 is formed by multi-layer superposition, and a certain amount of voltage is applied to it to cause the PVC gel film 32 to shrink and deform. Compared with traditional mechanical transmission, it can meet the needs of displacement drive in a small space.

[0044] In an optional embodiment, in order to achieve the aperture change of the sound absorption hole, at least two diameter sizes of sound absorption holes are provided on the sound absorption chamber 12 and the upper cover plate 2, so as to facilitate the aperture change and achieve the sound absorption adjustment of different frequencies. Among them, the diameters of the first sound absorption hole 121 and the second sound absorption hole 122 located in the same sound absorption chamber 12 are not equal; the diameters of the third sound absorption hole 21 and the fourth sound absorption hole 22 located in the same connecting area are not equal.

[0045] Furthermore, during the aperture change process, the upper cover plate 2 slides on the main cavity 1 along the first direction. Therefore, an inverted L-shaped slide groove 11 is provided on two opposite sides of the top of the main cavity 1 along the second direction. Figure 3 As shown, the two inverted L-shaped slots 11 are parallel to each other and extend along the first direction; wherein the first direction and the second direction are perpendicular to each other. The two ends of the upper cover plate 2 are slidably connected to the inverted L-shaped slots 11. In other words, the two ends of the upper cover plate 2 are both located in the inverted L-shaped slots 11. It can be understood that Figure 5As shown, stepped steps corresponding to the inverted L-shaped slide groove 11 are also provided at both ends of the upper cover plate 2 , and the stepped steps are embedded in the inverted L-shaped slide groove 11 .

[0046] Furthermore, blocks are provided on opposite sides of the top of the main cavity 1 along the first direction. The two blocks are symmetrically arranged and both extend along the second direction to limit the movement of the upper cover plate 2. In other words, the inverted L-shaped slide groove 11 and the block work together to ensure that the upper cover plate 2 only moves along the first direction and can reach the position accurately.

[0047] In an optional embodiment, if Figure 3 and Figure 4 As shown, a driver placement cavity 14 is provided in the main body cavity 1 , and the PVC gel driver 3 is arranged in the driver placement cavity 14 .

[0048] In an optional embodiment, if Figure 3 and Figure 4 As shown, a rectangular groove 13 is arranged on the top of one side of the main cavity 1 , the length direction of the rectangular groove 13 is arranged along the first direction, and the rectangular groove 13 is located on the top of the driver placement cavity 14 .

[0049] In an optional embodiment, the parallel Helmholtz resonance cavity with adjustable sound absorption performance further includes: a driver connection block 4, such as Figure 7 and Figure 8 As shown, Figure 7 is a schematic structural diagram of a driver connection block provided by an embodiment of the present invention; Figure 8 It is a structural schematic diagram of an upper cover plate, a driver connecting block and a PVC gel driver provided in an embodiment of the present invention.

[0050] Specifically, the driver connecting block 4 is L-shaped, and the first end of the driver connecting block 4 is vertically connected to the second end of the PVC gel driver 3 ; the first end of the driver connecting block 4 is connected to the PVC gel driver 3 , and the second end of the PVC gel driver 3 is connected to the upper cover plate 2 .

[0051] Furthermore, a protrusion 41 is provided at the second end of the driver connecting block 4 . The protrusion 41 is located in the rectangular groove 13 and connected to the bottom surface of the upper cover plate 2 .

[0052] The principle is that when the PVC gel driver 3 contracts when powered on, the driver connecting block 4 moves with the contraction of the PVC gel driver 3, and at the same time, the protrusion 41 partially passes through the rectangular groove 13 to connect with the bottom surface of the upper cover plate 2, and the protrusion 41 slides in the rectangular groove 13 and drives the upper cover plate 2 to slide along the first direction, so that the sound absorption holes on the upper cover plate 2 and the sound absorption holes of corresponding size and position on the sound absorption chamber 12 completely overlap and are connected to each other.

[0053] In an optional embodiment, the parallel Helmholtz resonance cavity with adjustable sound absorption performance further includes: a driver side plate 5, such as Fig. 9 As shown, Fig. 9 It is a schematic structural diagram of a driver side plate provided in an embodiment of the present invention.

[0054] Specifically, the driver side panel 5 is arranged on the side of the main body cavity 1; the driver side panel 5 is detachably connected to the driver placement cavity 14, and a wire outlet groove 51 is arranged in the middle of the driver side panel 5 to facilitate the security of the PVC gel driver 3 and the lead-out of the wires.

[0055] The working principle of the parallel Helmholtz resonance cavity with adjustable sound absorption performance of this embodiment is that the upper cover plate 2 is arranged on the top of the main body cavity 1 and stuck in the inverted L-shaped slide groove 11, and the upper cover plate 2 is provided with a plurality of connecting areas, and the third sound absorption hole 21 and the fourth sound absorption hole 22 on each connecting area have a difference in diameter; at the same time, a plurality of sound absorption chambers 12 are arranged in parallel inside the main body cavity 1, and the top surface of each sound absorption chamber 12 is provided with a first sound absorption hole 121 and a second sound absorption hole 122, and the diameters of the first sound absorption hole 121 and the second sound absorption hole 122 are different. Taking the gradual decrease in diameter as an example, the diameter of the first sound absorption hole 121 is smaller than the diameter of the second sound absorption hole 122, the diameter of the third sound absorption hole 21 is smaller than the diameter of the fourth sound absorption hole 22, and the direction vector of the center line from the second sound absorption hole 122 to the first sound absorption hole 121 is equal in length and has the same direction as the direction vector of the center line from the fourth sound absorption hole 22 to the third sound absorption hole 21. The anode metal mesh 31, the PVC gel film 32 and the cathode conductive sheet 33 are stacked in sequence to form a group of PVC gel laminated drive units, and a plurality of groups of PVC gel laminated drive units form a PVC gel driver 3. The assembled PVC gel driver 3 is placed in the driver placement cavity 14. A card slot is provided on one side of the main body cavity 1, and the driver side plate 5 is snapped into the card slot on one side of the main body cavity 1. The PVC gel driver 3 located in the driver placement cavity 14 leads out the wire through the outlet slot 51 in the middle of the driver side plate 5 to connect to an external power source.

[0056] like Fig.10 As shown, Fig.10 1 is a schematic diagram of the state of the upper cover plate when not powered on provided by an embodiment of the present invention. When the PVC gel driver 3 is not powered on, the PVC gel driver 3 is in a stationary state, and the upper cover plate 2 is in contact with the block on the first side of the top of the main cavity 1. At this time, the first sound absorption holes 121 on the plurality of sound absorption chambers 12 are overlapped and connected with the third sound absorption holes 21 on the plurality of connecting areas in a one-to-one correspondence, and sound waves can pass through the sound absorption holes to achieve corresponding resonance sound absorption.

[0057] like Fig.11 As shown, Fig.111 is a schematic diagram of the state of the upper cover plate when powered on according to an embodiment of the present invention. When the PVC gel driver 3 is powered on and the voltage is stable, the PVC gel driver 3 is in a contracted state, and the upper cover plate 2 is in contact with the block on the second side of the top of the main cavity 1. At this time, the second sound absorption holes 122 on the plurality of sound absorption chambers 12 are overlapped and connected with the fourth sound absorption holes 22 on the plurality of connecting areas in a one-to-one correspondence, and sound waves can pass through the sound absorption holes to achieve corresponding resonance sound absorption.

[0058] It should be noted that the number and size parameters of the sound absorption chambers 12 of the parallel Helmholtz resonance cavity with adjustable sound absorption performance in this embodiment, as well as the positions and size parameters of the sound absorption holes can be obtained based on relevant existing technologies, and further, by reasonably setting the sound absorption chambers 12 and the sound absorption holes, a low-frequency broadband sound absorption effect for a specific sound absorption frequency can be achieved.

[0059] Exemplarily, the Helmholtz resonator is composed of the inner cavity of the sound absorption chamber 12 and the sound absorption hole. The resonant frequency of a single Helmholtz resonant cavity is expressed as:

[0060]

[0061] Wherein, f is the resonance frequency of a single Helmholtz resonator; c0 is the speed of sound in air; d is the diameter of the sound absorbing hole; c is the height of the through hole formed by the overlap of the sound absorbing holes; and V is the volume of the internal cavity of a single sound absorbing chamber 12 .

[0062] It can be seen from formula (1) that the sound absorption coefficient of the parallel Helmholtz resonance cavity is closely related to its size parameters. Therefore, the sound absorption performance of the parallel Helmholtz resonance cavity can be adjusted by setting the sound absorption cavity 12 and the sound absorption hole, thereby achieving a low-frequency broadband sound absorption effect for a specific sound absorption frequency. However, in this embodiment, no restrictions are imposed on the specific settings of the sound absorption cavity 12 and the sound absorption hole.

[0063] Take a parallel Helmholtz resonance cavity with adjustable sound absorption performance with an outer dimension of L×W×H=100×100×34 mm as an example, where L is the length dimension, W is the width dimension, and H is the height dimension.

[0064] Exemplarily, six sound absorption chambers 12 are connected in parallel in the main body cavity 1, and the size parameters of the six sound absorption chambers 12 are shown in Table 1, wherein w is the width dimension of the sound absorption chamber 12; l is the length dimension of the sound absorption chamber 12; h is the height dimension of the sound absorption chamber 12; d1 is the diameter dimension of the third sound absorption hole 21 (smaller hole) in the upper cover plate 2, and is also the diameter dimension of the first sound absorption hole 121; d2 is the diameter dimension of the fourth sound absorption hole 22 (larger hole) in the upper cover plate 2, and is also the diameter dimension of the second sound absorption hole 122.

[0065] After the overlap connection, the height of the formed through hole is c=3 mm, the distance b1 between the smaller hole and the larger hole in the main cavity 1 is b1=10 mm, and the distance b2 between the smaller hole and the larger hole in the upper cover plate 2 is b2=16 mm.

[0066] Table 1 Dimensional parameters of the sound absorption chamber

[0067]

[0068] Furthermore, the parallel Helmholtz resonant cavity with adjustable sound absorption performance in the example was simulated using the finite element simulation software COMSOL. The simulation conditions were respectively the energized state and the unenergized state. The simulation results of the sound absorption coefficient were obtained as follows: Fig.12 As shown, Fig.12 It is a simulation result diagram of a parallel Helmholtz resonance cavity with adjustable sound absorption performance provided by an embodiment of the present invention.

[0069] When no voltage is applied, the resonance sound absorption effect of the smaller holes and the sound absorption chamber 12 can produce a sound absorption effect with a frequency ranging from 365 Hz to 495 Hz, an average sound absorption coefficient greater than 0.8, and a sound absorption bandwidth of 130 Hz.

[0070] After the voltage U is applied, the resonance sound absorption effect of the larger hole and the sound absorption chamber 12 can produce a sound absorption effect with a frequency in the range of 265 Hz to 375 Hz, an average sound absorption coefficient greater than 0.8, and a sound absorption bandwidth of 110 Hz.

[0071] It can be seen from the simulation results that the parallel Helmholtz resonance cavity with adjustable sound absorption performance of this embodiment can achieve adjustable sound absorption frequency with a small overall size, which can meet the noise reduction requirements in a small space and achieve effective noise control.

[0072] The Helmholtz resonance cavity with adjustable sound absorption performance of the present invention generates multiple sound absorption peaks through the design of parallel sound absorption chambers, has the advantage of compact structure, and can achieve broadband sound absorption effect. At the same time, without changing the size parameters and structure of the sound absorption chamber, the energized contraction characteristics of the PVC gel driver and the mutual cooperation of the sound absorption holes are used to achieve the aperture change of the overlapping and connected sound absorption holes. The sound absorption frequency can be adjusted in real time according to the needs of the application scenario to achieve low-frequency broadband sound absorption effects for different frequencies.

[0073] The Helmholtz resonance cavity with adjustable sound absorption performance of the present invention uses voltage as a control signal to control the PVC gel driver. Compared with the traditional adjustment method based on mechanical component drive and based on changing size parameters or structural adjustment, it has a smaller structure and is easier to operate, which is more conducive to the lightweight and compactness of the overall structure and has broad application prospects.

[0074] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is 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 of the present invention.

[0075] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A parallel Helmholtz resonance cavity with adjustable sound absorption performance, characterized in that: include: A main body cavity (1) is provided with a plurality of sound absorbing chambers (12) arranged in parallel therein, and a first sound absorbing hole (121) and a second sound absorbing hole (122) are arranged at intervals along a first direction on the top surface of each of the sound absorbing chambers (12); An upper cover plate (2) covers the top surfaces of the plurality of sound absorbing chambers (12) and is slidably connected to the main cavity (1) along the first direction; the upper cover plate (2) is provided with a plurality of connecting areas, and each of the connecting areas is provided with a third sound absorbing hole (21) and a fourth sound absorbing hole (22) at intervals along the first direction; A plurality of the sound absorbing chambers (12) are arranged in one-to-one correspondence with a plurality of the connecting areas, the diameters of the corresponding first sound absorbing holes (121) and the third sound absorbing holes (21) are equal, and the diameters of the corresponding second sound absorbing holes (122) and the fourth sound absorbing holes (22) are equal; A PVC gel driver (3) is connected to the upper cover plate (2); when the PVC gel driver (3) is not powered on, the corresponding first sound absorption hole (121) overlaps and communicates with the third sound absorption hole (21); when the PVC gel driver (3) is powered on, the PVC gel driver (3) contracts so that the corresponding second sound absorption hole (122) overlaps and communicates with the fourth sound absorption hole (22).

2. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 1, characterized in that: An inverted L-shaped slide groove (11) is provided on two opposite sides of the top of the main body cavity (1) along a second direction, and two ends of the upper cover plate (2) are slidably connected to the inverted L-shaped slide groove (11); wherein the first direction and the second direction are perpendicular to each other.

3. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 1, characterized in that: Stoppers are arranged on two opposite sides of the top of the main body cavity (1) along a first direction.

4. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 1, characterized in that: The diameters of the first sound absorption hole (121) and the second sound absorption hole (122) located in the same sound absorption chamber (12) are not equal; the diameters of the third sound absorption hole (21) and the fourth sound absorption hole (22) located in the same connecting area are not equal.

5. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 1, characterized in that: A rectangular groove (13) is provided at the top of one side of the main body cavity (1), and the length direction of the rectangular groove (13) is arranged along the first direction.

6. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 5, characterized in that: A driver placement cavity (14) is provided in the main body cavity (1), the PVC gel driver (3) is arranged in the driver placement cavity (14), and the rectangular groove (13) is located at the top of the driver placement cavity (14).

7. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 1, characterized in that: The PVC gel driver (3) comprises: a plurality of groups of PVC gel laminated drive units, each group of the PVC gel laminated drive units comprises: a plurality of layers of anode metal mesh (31), PVC gel film (32) and cathode conductive sheet (33) stacked in sequence.

8. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 5, characterized in that: Also includes: A driver connection block (4), wherein the driver connection block (4) is L-shaped, a first end of the driver connection block (4) is connected to the PVC gel driver (3), and a second end of the PVC gel driver (3) is connected to the upper cover plate (2).

9. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 8, characterized in that: The second end of the driver connection block (4) is provided with a protrusion (41), and the protrusion (41) is located in the rectangular groove (13) and connected to the bottom surface of the upper cover plate (2).

10. The parallel Helmholtz resonance cavity with adjustable sound absorption performance according to claim 6, characterized in that: Also includes: A driver side plate (5), the driver side plate (5) being detachably connected to the driver placement cavity (14), and a wire outlet groove (51) being arranged in the middle of the driver side plate (5).

Images