Adjustable sound absorber

Abstract

The utility model discloses an adjustable sound absorber which comprises a cylindrical cavity shell, an inner cavity of the cylindrical cavity shell is provided with three partition plates, the partition plates divide the inner cavity of the cylindrical cavity shell into three fan-shaped resonant cavities, the sizes of the three resonant cavities are the same, the side wall of the cylindrical cavity shell is provided with three sound inlets, and the sound inlets are communicated with the three fan-shaped resonant cavities. The three sound inlets correspond to the three resonant cavities respectively, a fan-shaped shell is arranged in each resonant cavity, a first through hole is formed in the top of each fan-shaped shell, a sound wave absorption channel is defined by the side wall of each fan-shaped shell and the inner wall of the corresponding resonant cavity, the sound inlets are communicated with the sound wave absorption channels, and an impedance modulation interface is formed in a top plate of the cylindrical cavity shell. The impedance modulation interface is communicated with an inner cavity of the fan-shaped shell through the first through hole, a second through hole is further formed in the side wall of the fan-shaped shell, and the sound wave absorption channel is communicated with the inner cavity of the fan-shaped shell through the second through hole; and the shielding piece is provided with a shielding part, and the shielding part can rotate to the position of the impedance modulation interface in the horizontal direction. The adjustable sound absorber is good in ventilation effect, and the adjustable sound absorption frequency is large in low-frequency absorption coverage range.

Description

Technical Field

[0001] The utility model relates to the technical field of mufflers, and particularly relates to an adjustable sound absorber. Background Art

[0002] As a hot issue in current scientific research and industry, ventilation and noise reduction technology has attracted the attention of many industry insiders and relevant scientists. For the problem of ventilation and noise reduction, the wind speed ratio, absorption effect, and absorption frequency range are important indicators for measuring a sound absorber, and they are also the key factors for whether the sound absorber can come out of the laboratory and enter people's daily lives.

[0003] Most sound absorbers work through Helmholtz resonators. However, due to design problems, the existing sound absorbers have poor ventilation effects (low wind speed ratio) and a small adjustable absorption frequency range (even most sound absorbers are non-adjustable after being processed and formed). These designs will cause the airflow to be blocked by the sound absorber itself, reducing the working efficiency of ventilation ducts, central air conditioners, and exhaust systems. Content of the Utility Model

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the utility model provides an adjustable sound absorber with good ventilation effects and a large adjustable absorption frequency range.

[0005] The adjustable sound absorber according to the first aspect embodiment of the utility model includes:

[0006] A cylindrical cavity housing with three partition plates arranged in its inner cavity. The partition plates divide the inner cavity of the cylindrical cavity housing into three fan-shaped resonant cavities with the same size. Three sound inlet openings are arranged on the side wall of the cylindrical cavity housing, and the three sound inlet openings are respectively communicated with the three resonant cavities. A fan-shaped housing is arranged in each resonant cavity. A first through hole is opened at the top of the fan-shaped housing. A sound wave absorption channel is formed between the side wall of the fan-shaped housing and the inner wall of the resonant cavity. The sound inlet opening is communicated with the sound wave absorption channel. An impedance adjustment opening is arranged on the top plate of the cylindrical cavity housing, and the impedance adjustment opening is communicated with the inner cavity of the fan-shaped housing through the first through hole. A second through hole is also arranged on the side wall of the fan-shaped housing, and the sound wave absorption channel is communicated with the inner cavity of the fan-shaped housing through the second through hole;

[0007] A shielding member rotatably arranged above the top plate of the cylindrical cavity housing. The center of the shielding member coincides with the central axis of the cylindrical cavity housing. The shielding member is provided with a shielding portion that can rotate around the central axis and rotate to the position of the impedance adjustment opening to adjust the opening size of the impedance adjustment opening.

[0008] The adjustable sound absorber according to the embodiments of the present utility model has at least the following beneficial effects: The adjustable sound absorber is provided with three coupled resonant cavities in a cylindrical cavity housing. A sector-shaped housing is arranged in the resonant cavity, and a sound wave absorption channel is formed between the side wall of the sector-shaped housing and the inner wall of the resonant cavity. When the air discharged by the exhaust system passes through the cylindrical cavity, the air rubs and vibrates with the pipe wall and the adjustable sound absorber to generate noise. The sound wave causing the noise will enter the sound wave absorption channel from the sound inlet of the adjustable sound absorber. During the process of passing through the sound wave absorption channel, the sound wave will rub against the outer wall of the sector-shaped housing and the inner wall of the resonant cavity, generating heat through friction, thereby consuming the sound wave energy, further reducing the resonance frequency of the sound wave. Then, the sound wave with the reduced resonance frequency enters the sector-shaped housing through the sound wave absorption channel and continues to rub against the inner wall of the sector-shaped housing in the cavity of the sector-shaped housing, consuming the sound wave energy, and the resonance frequency continuously decreases, achieving the purpose of noise reduction. The adjustable sound absorber effectively reduces the sound wave resonance passing through the exhaust system, reduces noise, and has good ventilation effect. At the same time, the setting of the shielding member can adjust the frequency of sound wave absorption, making the adjustable sound absorber more applicable.

[0009] According to some embodiments of the present utility model, the shape of the sound inlet is rectangular, the sound inlet is vertically arranged along the outer wall of the cylindrical cavity housing, and the three sound inlets are evenly arranged circumferentially around the circular cavity housing.

[0010] According to some embodiments of the present utility model, the second through hole is located on the side wall of the sector-shaped housing and at the central angle of the sector-shaped housing.

[0011] According to some embodiments of the present utility model, the cross-sectional area of the first through hole is the area of the top of the sector-shaped housing minus the cross-sectional area of the side wall of the sector-shaped housing, and the first through hole communicates with the second through hole.

[0012] According to some embodiments of the present utility model, the three impedance adjustment ports are evenly arranged circumferentially around the center of the top plate of the cylindrical cavity housing.

[0013] According to some embodiments of the present utility model, the shielding member is a circular turntable, the shielding member is provided with three arc-shaped through holes, the three arc-shaped through holes are evenly arranged circumferentially around the central axis, and the shielding portion is located between the adjacent arc-shaped through holes.

[0014] According to some embodiments of the present utility model, the shielding member is a structure in which three fan blades are coupled, the fan blades are the shielding portions, and the three fan blades are evenly arranged circumferentially around the central axis.

[0015] According to some embodiments of the present utility model, a driving mechanism is further included. The driving mechanism is provided with a mounting bracket, a driver, a rotating shaft and a limiting block. The driver and the limiting block are mounted on the mounting bracket. The cylindrical cavity housing is clamped between the driver and the limiting block. The rotating shaft passes through the cylindrical cavity housing and the shielding member. The rotating shaft coincides with the central axis of the cylindrical cavity housing. One end of the rotating shaft is fixedly connected to the output shaft of the driver, and the other end is rotatably connected to the limiting block.

[0016] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following further describes the present utility model in conjunction with the drawings and embodiments, where:

[0018] Figure 1 is a schematic diagram of an adjustable sound absorber according to an embodiment of the present utility model;

[0019] Figure 2 is a schematic diagram of an adjustable sound absorber according to another embodiment of the present utility model;

[0020] Figure 3 is Figure 1 a schematic diagram of the cylindrical cavity housing of the adjustable sound absorber shown;

[0021] Figure 4 is Figure 3 a schematic diagram of the interior of the cylindrical cavity housing shown;

[0022] Figure 5 is an experimental absorption spectrum diagram of the adjustable lowest frequency;

[0023] Figure 6 is an experimental absorption spectrum diagram of the adjustable highest frequency;

[0024] Figure 7 is an experimental result diagram of the wind speed ratio test.

[0025] Reference numerals:

[0026] Cylindrical cavity housing 100, sound inlet 110, impedance adjustment port 120, partition plate 130, sector housing 140, first through hole 141, second through hole 142, sound wave absorption channel 150, shielding member 200, shielding portion 210, driving mechanism 300, mounting plate 310, connecting rod 320, driver 330, rotating shaft 340, limiting block 350. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation of the present utility model.

[0028] In the description of the present utility model, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model 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 should not be construed as a limitation of the present utility model.

[0029] In the description of the present utility model, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceeding, etc. are understood as not including the present number, and above, below, within, etc. are understood as including the present number. If there is a description of first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0030] In the description of the present utility model, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present utility model in combination with the specific content of the technical solution.

[0031] As a hot topic of current scientific research and industry, the ventilation and noise reduction technology has attracted the attention of many industry insiders and related scientists. For the ventilation and noise reduction problem, the wind speed ratio, absorption effect, and absorption frequency range are important indicators for measuring the sound absorber, and they are also the key factors for the sound absorber to come out of the laboratory and enter everyone's daily life.

[0032] The vast majority of sound absorbers work through Helmholtz resonators. However, due to design problems, the existing sound absorbers have poor ventilation effects (low wind speed ratio) and a small adjustable absorption frequency range (even most sound absorbers are non-adjustable after being processed and formed). These designs will cause the airflow to be blocked by the sound absorber itself, reducing the working efficiency of ventilation ducts, central air conditioners, and exhaust systems themselves.

[0033] In view of the technical problems existing in the prior art, the present utility model proposes an adjustable sound absorber. The adjustable sound absorber is made of acoustic metamaterials, has good ventilation ability (high wind speed ratio), and excellent sound absorption effect. Specifically, the adjustable sound absorber is provided with three coupled resonant cavities in a cylindrical cavity housing. A sector-shaped housing is arranged in the resonant cavity. The side wall of the sector-shaped housing and the inner wall of the resonant cavity enclose a sound wave absorption channel. When the wind discharged by the exhaust system passes through the cylindrical cavity housing, the wind discharged and the pipe wall, as well as the noise generated by the friction vibration of the outer wall of the adjustable sound absorber, cause the sound waves of the noise to enter the sound wave absorption channel from the sound inlet on the side wall of the cylindrical cavity housing. During the process of passing through the sound wave absorption channel, the sound waves will generate heat by friction with the outer wall of the sector-shaped housing and the inner wall of the resonant cavity, thereby consuming the sound wave energy, reducing the resonance frequency of the sound waves, and then the sound waves with the reduced resonance frequency enter the sector-shaped housing through the sound wave absorption channel and continue to generate friction with the inner wall of the sector-shaped housing in the cavity of the sector-shaped housing, consuming the sound wave energy, and the resonance frequency continues to decrease, so as to achieve the effect of sound absorption and noise reduction. The present invention mainly utilizes the mutual coupling of three Helmholtz resonant cavities to reduce the sound absorption frequency, improve the sound absorption efficiency and the wind speed ratio, and utilizes the impedance adjustment port at the top to realize the adjustable function.

[0034] Referring to Figures 1 to 4 , it can be understood that the adjustable sound absorber provided by the embodiment of the present utility model includes a cylindrical cavity housing 100 and a shielding member 200. Specifically, three partition plates 130 are arranged in the inner cavity of the cylindrical cavity housing 100. The partition plates 130 divide the inner cavity of the cylindrical cavity housing 100 into three sector-shaped resonant cavities. The sizes of the three resonant cavities are the same. Three sound inlets 110 are arranged on the side wall of the cylindrical cavity housing 100. The three sound inlets 110 respectively correspond to the three resonant cavities. A sector-shaped housing 140 is arranged in each resonant cavity. A first through hole 141 is opened at the top of the sector-shaped housing 140. The side wall of the sector-shaped housing 140 and the inner wall of the resonant cavity enclose a sound wave absorption channel 150. The sound inlet 110 communicates with the sound wave absorption channel 150. An impedance adjustment port 120 is arranged on the top plate of the cylindrical cavity housing 100. The impedance adjustment port 120 communicates with the inner cavity of the sector-shaped housing 140 through the first through hole 141. A second through hole 142 is also arranged on the side wall of the sector-shaped housing 140. The sound wave absorption channel 150 communicates with the inner cavity of the sector-shaped housing 140 through the second through hole 142. The sound waves pass through the sound inlet 110, the sound wave absorption channel 150, the second through hole 142, and the inner cavity of the sector-shaped housing 140 in sequence. The shielding member 200 is rotatably arranged above the top plate of the cylindrical cavity housing 100. The center of the shielding member 200 coincides with the central axis of the cylindrical cavity housing 100. The shielding member 200 is provided with a shielding portion 210. The shielding portion 210 can rotate horizontally to the position of the impedance adjustment port 120 to adjust the opening size of the impedance adjustment port 120.

[0035] It should be noted that the shape of the sound inlet 110 is rectangular, and the sound inlet 110 is vertically arranged along the outer wall of the main body. Such a design can enable sound waves to quickly fill the sound absorption channel 150 after entering the sound absorption channel 150, making it easier for the sound waves to enter the adjustable sound absorber. The second through hole 142 is located at the central angle of the sector-shaped housing 140, and the second through hole 142 is also a rectangular through hole. The first through hole 141 is a sector-shaped through hole, and the area of the first through hole 141 is equal to the area of the top of the sector-shaped housing 140 minus the area of the cross-section of the side wall of the sector-shaped housing 140. Such a design can make the area of the first through hole 141 larger and improve the sound wave entry efficiency.

[0036] It should be noted that the three impedance adjustment ports 120 are arranged in a circumferential array along the top plate of the cylindrical cavity housing 100. In some embodiments, the shielding member 200 is a circular turntable, and the shielding member 200 is provided with three arc-shaped through holes, which correspond to the three impedance adjustment ports 120 one by one, and the shielding portion 210 is located between adjacent arc-shaped through holes. In other embodiments, the shielding member 200 is a structure in which three fan blades are coupled, and the fan blades are the shielding portions 210, and the central angles of the fan blades point to the central axis of the cylindrical cavity housing 100.

[0037] It can be understood that for the embodiment in which the shielding member 200 is a circular turntable, the overlapping area between the arc-shaped through hole and the impedance adjustment port 120 can be adjusted to adjust the opening degree of the impedance adjustment port 120; for the structure in which the shielding member 200 is a structure in which three fan blades are coupled, the overlapping area between the fan blade and the impedance adjustment port 120 can be adjusted to adjust the opening degree of the impedance adjustment port 120.

[0038] It should be noted that the adjustable sound absorber further includes a driving mechanism 300. The driving mechanism 300 is provided with a mounting bracket, a driver 330, a rotating shaft 340 and a limiting block 350. The driver 330 and the limiting block 350 are installed on the mounting bracket. The cylindrical cavity housing 100 is clamped between the driver 330 and the limiting block 350. The rotating shaft 340 passes through the cylindrical cavity housing 100 and the shielding member 200, and the rotating shaft 340 coincides with the central axis of the cylindrical cavity housing 100. One end of the rotating shaft 340 is fixedly connected to the output shaft of the driver 330, and the other end is rotatably connected to the limiting block 350. Among them, the mounting bracket is provided with a mounting plate 310 and a connecting rod 320. The driver 330 is installed on the mounting plate 310. One end of the connecting rod 320 is installed on the mounting plate 310, and the other end is connected to the limiting block 350. The limiting block 350 is a "T"-shaped block.

[0039] It should be noted that the cylindrical cavity housing 100 of the adjustable sound absorber is made of photosensitive resin. The rotation of the shielding member 200 changes the size of the impedance adjustment port 120, which can adjust the position of the absorption peak. The impedance adjustment port 120 can change the impedance value of a single resonant cavity and change its resonant frequency, thereby achieving the effect of adjustable sound absorption.

[0040] Referring to Figures 5 to 7 , it can be seen from the experimental data that under specific product geometric parameters, super-breathable adaptive adjustable sound absorption with a low-frequency adjustable range of 600 - 950 Hz can be achieved, and the wind speed ratio can reach 95.9%. The adjustable sound absorber provided by the embodiment of the present invention can perform super-breathable sound absorption and generally applies to any frequency band. However, since this Helmholtz resonator sound absorption method is generally not used for high-frequency acoustic noise, it is mainly used for sound absorption and noise reduction in the low-frequency band (noise frequency less than 1000 Hz).

[0041] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. An adjustable sound absorber, characterized in that, Comprising: A cylindrical cavity housing, with three partition plates arranged in the inner cavity. The partition plates divide the inner cavity of the cylindrical cavity housing into three fan-shaped resonant cavities. The sizes of the three resonant cavities are the same. Three sound inlet ports are arranged on the side wall of the cylindrical cavity housing, and the three sound inlet ports are respectively communicated with the three resonant cavities. A fan-shaped housing is arranged in each resonant cavity. A first through hole is opened at the top of the fan-shaped housing. The side wall of the fan-shaped housing and the inner wall of the resonant cavity enclose a sound absorption channel. The sound inlet port is communicated with the sound absorption channel. An impedance adjustment port is arranged on the top plate of the cylindrical cavity housing. The impedance adjustment port is communicated with the inner cavity of the fan-shaped housing through the first through hole. A second through hole is also arranged on the side wall of the fan-shaped housing. The sound absorption channel is communicated with the inner cavity of the fan-shaped housing through the second through hole; A shielding member, rotatably arranged above the top plate of the cylindrical cavity housing. The center of the shielding member coincides with the central axis of the cylindrical cavity housing. The shielding member is provided with a shielding portion. The shielding portion can rotate around the central axis and move to the position of the impedance adjustment port to adjust the opening size of the impedance adjustment port.

2. The adjustable sound absorber according to claim 1, characterized in that, The shape of the sound inlet port is rectangular. The sound inlet port is arranged vertically along the outer wall of the cylindrical cavity housing, and the three sound inlet ports are evenly arranged circumferentially around the cylindrical cavity housing.

3. The adjustable sound absorber according to claim 1, characterized in that, The second through hole is located on the side wall of the fan-shaped housing and at the central angle of the fan-shaped housing.

4. The adjustable sound absorber according to claim 1, characterized in that, The cross-sectional area of the first through hole is the area of the top of the fan-shaped housing minus the cross-sectional area of the side wall of the fan-shaped housing, and the first through hole is communicated with the second through hole.

5. The adjustable sound absorber according to claim 1, characterized in that, The three impedance adjustment ports are evenly arranged circumferentially around the center of the top plate of the cylindrical cavity housing.

6. The adjustable sound absorber according to claim 5, characterized in that, The shielding member is a circular turntable. The shielding member is provided with three arc-shaped through holes, and the three arc-shaped through holes are evenly arranged circumferentially around the central axis. The shielding portion is located between the adjacent arc-shaped through holes.

7. The adjustable sound absorber according to claim 5, characterized in that, The shielding member is a structure coupled by three fan blades. The fan blades are the shielding portions, and the three fan blades are evenly arranged circumferentially around the central axis.

8. The adjustable sound absorber according to claim 1, characterized in that, It further includes a driving mechanism. The driving mechanism is provided with a mounting frame, a driver, a rotating shaft and a limiting block. The driver and the limiting block are mounted on the mounting frame. The cylindrical cavity housing is clamped between the driver and the limiting block. The rotating shaft passes through the cylindrical cavity housing and the shielding member. The rotating shaft coincides with the central axis of the cylindrical cavity housing. One end of the rotating shaft is fixedly connected to the output shaft of the driver, and the other end is rotatably connected to the limiting block.

Images