Noise reduction assembly, silencer and vehicle

Abstract

The embodiment of the invention provides a noise reduction assembly, a silencer and a vehicle, and relates to the technical field of noise elimination and noise reduction, the noise reduction assembly comprises an annular baffle, a first channel is formed in the inner side of the annular baffle, and a first through hole penetrating through the annular baffle in the thickness direction is formed in the annular baffle; the annular shell is arranged outside the annular baffle in a sleeving manner, and a first cavity is formed in the annular shell; the floating plate is located in the first cavity, and a first noise reduction cavity communicating with the first through hole is formed between the floating plate and the cavity wall of the first cavity in a matched mode; and the adjusting part is used for adjusting the position of the floating plate in the first cavity so as to adjust the volume of the first noise reduction cavity, so that the noise reduction assembly can adjust the resonance frequency according to the actual situation, and the noise reduction requirements of sound waves with different frequencies are met.

Description

Technical Field

[0001] The present application relates to the technical field of sound attenuation and noise reduction, and in particular to a noise reduction component, a muffler and a vehicle. Background Art

[0002] Muffler is a device used to reduce noise and is widely used in various mechanical and industrial equipment, such as automobile engines, generator sets, air conditioning systems, etc.

[0003] Acoustic metamaterials can achieve precise control of sound waves by designing internal structures, such as negative refraction, sound wave focusing, and sound wave shielding. They are an important component of most current mufflers.

[0004] The structure of existing acoustic metamaterials is fixed and cannot be adjusted once they are manufactured. Acoustic metamaterials are also very sensitive to structural dimensions. If there is a large error in product manufacturing, it will cause a large shift in the sound insulation peak, making it impossible to adapt to noise control at a specific frequency. Summary of the invention

[0005] The embodiments of the present application provide a noise reduction component, a muffler and a vehicle to solve the problem that if the acoustic metamaterial used in the existing muffler has a large manufacturing error, it will not be able to adapt to the specific frequency noise control.

[0006] In a first aspect, an embodiment of the present application provides a noise reduction component, including:

[0007] An annular baffle, a first channel is formed inside the annular baffle, and a first through hole is provided on the annular baffle that penetrates the annular baffle in a thickness direction;

[0008] An annular shell, wherein the annular shell is sleeved outside the annular baffle, and a first cavity is arranged inside the annular shell;

[0009] a floating plate, the floating plate being located in the first cavity and cooperating with a cavity wall of the first cavity to isolate at least a portion of the first cavity to form a first noise reduction cavity communicating with the first through hole;

[0010] An adjusting component is used to adjust the position of the floating plate in the first cavity to adjust the volume of the first noise reduction cavity.

[0011] In a possible implementation manner, the floating plate is an annular plate, and the moving direction of the floating plate is the same as the extending direction of the annular baffle.

[0012] In a possible implementation manner, a microphone is further included, and the microphone is located at the outlet end of the first channel, and the microphone is used to measure the real-time sound pressure level at the outlet end of the first channel.

[0013] In a possible implementation manner, the adjusting component includes a driving motor, an output end of the driving motor is connected to the floating plate, and the driving motor is used to adjust the position of the floating plate according to the real-time sound pressure level.

[0014] In a possible embodiment, the adjusting component includes a screw rod provided on the annular shell, the screw rod passes through the floating plate and is slidably connected to the floating plate, and two positioning blocks threadedly connected to the screw rod are provided on the screw rod, and the two positioning blocks are respectively provided on both sides of the floating plate and abut against the surface of the floating plate to limit the relative position of the floating plate and the screw rod.

[0015] In a possible embodiment, an annular protrusion is provided on at least one side of the two sides in the extension direction of the annular baffle, and the annular protrusion extends into the first cavity or the first channel. A second through hole passing through the annular protrusion is provided on the annular protrusion, and the second through hole is connected to the first through hole.

[0016] In a possible implementation manner, at least one end of the annular baffle is provided with a mounting portion extending to the outside of the annular housing.

[0017] In a second aspect, an embodiment of the present application provides a muffler, comprising:

[0018] It comprises a conductive member and the noise reduction component described in any one of the first aspects, wherein the conductive member is provided with a second channel, and an inlet end of the first channel is connected to an outlet end of the second channel.

[0019] In a possible implementation, at least two noise reduction components are provided along the moving direction of the sound wave, and the first channels of at least two of the noise reduction components are interconnected.

[0020] In a possible embodiment, a sound absorbing component is further included, and the sound absorbing component is located between the noise reduction component and the conductive component, or the sound absorbing component is located on the side of the noise reduction component away from the conductive component, and the frequency corresponding to the noise in the sound waves processed by the sound absorbing component is greater than the frequency corresponding to the noise in the sound waves processed by the noise reduction component.

[0021] In a possible implementation, the sound absorbing component includes:

[0022] a shell, wherein a third channel is disposed in the shell, and the third channel is communicated with the first channel;

[0023] A first sound absorbing component, wherein the first sound absorbing component is located in the third channel, and a plurality of second noise reduction cavities are provided on the first sound absorbing component, wherein at least one of the plurality of second noise reduction cavities has a different volume from the rest; and a plurality of third through holes are also provided on the first sound absorbing component, and each of the second noise reduction cavities is connected to the third channel through at least one of the third through holes.

[0024] In a possible implementation, the volumes of the plurality of second noise reduction chambers decrease or increase sequentially along the moving direction of the sound wave in the third channel.

[0025] In a possible implementation manner, a plurality of first sound absorbing components are sequentially arranged at intervals along the radial direction of the third channel.

[0026] In a possible implementation, the first sound absorbing component includes:

[0027] A main body component, wherein a plurality of cavities are disposed on two opposite sides of the main body component in the extension direction of the third channel;

[0028] Two cover plates are respectively arranged on both sides of the main body component and close the cavity to form the second noise reduction cavity. The third through hole is arranged on the cover plate and penetrates the cover plate along the thickness direction of the cover plate.

[0029] In a possible implementation, the main body component includes:

[0030] Middle partition;

[0031] Two grid support plates, each of which is provided with a plurality of through slots, and the two grid support plates are disposed on opposite sides of the middle partition plate, so that the cavity is formed by closing one end of the through slots through the middle partition plate;

[0032] Wherein, the cover plate is arranged on the side of the grid support plate away from the middle partition plate.

[0033] In a possible implementation, the two grid support plates have the same structure, and of the two cover plates, an effective area of ​​the third through hole on one is larger than an effective area of ​​the third through hole on the other cover plate.

[0034] In a possible implementation, the sound absorbing component further includes a second sound absorbing component located in the third channel, the second sound absorbing component is located at an inlet end or an outlet end of the first sound absorbing component, and a frequency corresponding to noise in sound waves processed by the second sound absorbing component is greater than a frequency corresponding to noise in sound waves processed by the first sound absorbing component.

[0035] In a possible implementation manner, the second sound absorption component includes a plurality of sound insulation cotton sheets that are sequentially arranged at intervals along the radial direction of the third channel.

[0036] In a third aspect, an embodiment of the present application provides a vehicle, including a vehicle body and the muffler according to any one of the second aspects, and the muffler is installed on the vehicle body.

[0037] In the noise reduction component, muffler and vehicle provided by the embodiments of the present application, the noise reduction component is provided with an annular baffle, an annular housing, a floating plate and an adjusting component. The annular housing is sleeved outside the annular baffle, and the floating plate is arranged in the first cavity on the annular housing and encloses a first noise reduction cavity with the cavity wall of the first cavity. Moreover, a first through hole provided on the annular baffle communicates the first channel inside the annular baffle with the first noise reduction cavity. During use, according to the frequency to be reduced of the sound wave to be reduced, the position of the floating plate can be adjusted through the adjusting component, so that the volume of the first noise reduction cavity changes to make the natural resonance frequency of the noise reduction component close to the frequency to be reduced. At this time, after the sound wave enters the first channel, it will enter the first noise reduction cavity through the first through hole and cause the vibration of the air column in the first through hole. Furthermore, the gas in the first noise reduction cavity resonates, resulting in the energy of the sound wave being exchanged back and forth between the first noise reducer and the first through hole, thereby consuming the energy of the sound wave and effectively reducing the noise. Compared with traditional acoustic metamaterials, the noise reduction component can adaptively adjust the position of the floating plate according to the actual use requirements, so that the noise reduction component can be adapted to reduce the noise of sound waves with different frequencies, the applicable sound wave frequency range is wide, and there will be no problem that it cannot be adapted to reduce the noise of specific frequency sound waves due to processing errors. At the same time, it can also reduce the requirements for processing accuracy of the noise reduction component, reduce the processing difficulty and processing cost. Description of the Drawings

[0038] The drawings here are incorporated into the description and constitute a part of this description, showing the embodiments that conform to the present application, and are used together with the description to explain the principles of the present application.

[0039] Figure 1 It is a schematic external structure diagram of the noise reduction component provided by the embodiment of the present application;

[0040] Figure 2 It is a schematic structural diagram of an implementation manner of the noise reduction component provided by the embodiment of the present application;

[0041] Figure 3 It is a schematic structural diagram of another implementation manner of the noise reduction component provided by the embodiment of the present application;

[0042] Figure 4 It is a schematic structural diagram of the first implementation manner of the muffler provided by the embodiment of the present application;

[0043] Figure 5Schematic diagram of the second implementation mode of the muffler provided by the embodiment of the present application;

[0044] Figure 6 Schematic diagram of the third implementation mode of the muffler provided by the embodiment of the present application;

[0045] Figure 7 Schematic diagram of the fourth implementation mode of the muffler provided by the embodiment of the present application;

[0046] Figure 8 Schematic diagram of the structure of the first sound absorption component in the muffler provided by the embodiment of the present application;

[0047] Figure 9 Schematic diagram of the change in the resonance frequency of the first sound absorption component in the muffler provided by the embodiment of the present application;

[0048] Figure 10 Schematic diagram of the internal structure of the muffler provided by the embodiment of the present application Figure 1 ;

[0049] Figure 11 Schematic diagram of the internal structure of the muffler provided by the embodiment of the present application Figure 2 ;

[0050] Figure 12 Exhaust noise spectrum of the vehicle;

[0051] Figure 13 Schematic diagram of the transmission loss when the floating plate of the noise reduction component provided by the embodiment of the present application is in different positions;

[0052] Figure 14 Schematic diagram of the transmission loss of the noise reduction component coupling provided by the embodiment of the present application;

[0053] Figure 15 Schematic diagram of the comparison of the transmission losses of the first sound absorption component and the second sound absorption component in the muffler provided by the embodiment of the present application;

[0054] Figure 16 Schematic diagram of the structure of the volume change direction of the first noise reduction cavity in the first sound absorption component in the muffler provided by the embodiment of the present application.

[0055] Reference numerals:

[0056] 100 - Noise reduction component, 110 - Ring-shaped housing, 111 - First cavity, 1111 - First noise reduction cavity, 120 - Ring-shaped baffle, 130 - First through hole, 131 - Ring-shaped protrusion, 140 - Floating plate, 150 - Adjusting component, 151 - Screw, 152 - Positioning block, 160 - First channel, 170 - Mounting part, 200 - Conductive part, 300 - Sound absorption component, 310 - Outer shell, 320 - Third channel, 330 - First sound absorption part, 331 - Middle partition plate, 332 - Cover plate, 333 - Third through hole, 334 - Grid support plate, 335 - Through groove, 336 - Second noise reduction cavity, 340 - Second sound absorption part.

[0057] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0058] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0059] First, the terms involved in the present application are explained:

[0060] Acoustic metamaterial: An artificially designed and manufactured material whose structural characteristics enable it to manipulate sound waves in ways that natural materials cannot achieve. These materials are usually composed of periodically arranged unit structures, and the size and shape of these structures determine the acoustic properties of the material. These acoustic properties include negative refractive index (enabling sound waves to propagate in the material in a negative refraction manner, thereby achieving abnormal deflection of sound waves), bandgap effect (preventing the propagation of sound waves within a specific frequency range, thereby achieving sound wave isolation and filtering), superlens effect (focusing sound waves to achieve a resolution higher than the diffraction limit), acoustic stealth (achieving acoustic stealth of an object by manipulating the propagation path of sound waves), etc.

[0061] Noise can be classified into three categories according to its energy distribution: noise with a wide energy distribution across frequency bands is called broadband noise, such as wideband random noise like road surface structure noise caused by random road surface excitation; noise with energy mainly concentrated in a few frequency components is called narrowband noise, such as engine order noise, which is the noise formed by the reciprocating motion of rotating equipment and has strong periodic characteristics; noise with energy distributed in both a few frequency components and a wide frequency band is called narrow and broadband mixed noise, and the mid-low frequency noise in the vehicle is a typical example.

[0062] However, most of the noise in the actual environment has the characteristics of narrow and broadband mixing. If noise reduction is achieved through active noise control technology based on phase cancellation, the following steps need to be experienced: The active noise control technology based on phase cancellation mainly cancels noise by generating sound waves with the same amplitude but opposite phase to the noise. It needs to first detect the noise in the environment and convert these noise signals into electrical signals, then analyze these noise signals through a signal processing unit, calculate and emit sound wave signals opposite to these noise signals, and then emit sound waves with opposite sound levels to the noise through a speaker. In this process, complex algorithms and real-time processing are involved, and it is also necessary to continuously adjust the generated sound waves according to the changes in the noise. The noise with the characteristics of narrow and broadband mixing has a very complex composition, which leads to problems such as high cost and non-convergent algorithms when the active noise control technology based on phase cancellation is applied to this environment.

[0063] In this regard, some acoustic metamaterials have emerged in recent years. Acoustic metamaterials provide some acoustic properties that transcend natural materials. For example, thin-film metamaterials can significantly reduce the thickness and mass density of sound insulation structures, but these technologies require inserting natural or artificial materials, which limits their ventilation ability. In addition, most of the structural units of acoustic metamaterials are passive, that is, once processed and formed, their material properties are fixed and cannot be changed. And acoustic metamaterials are extremely sensitive to structural dimensions. Once there are large errors in product manufacturing, the sound insulation peak value will shift to a large extent. These defects greatly limit the development of acoustic metamaterials. Therefore, there is an urgent need for acoustic metamaterials with flexible adjustable material properties and working frequency bands to adapt to the noise reduction of noise with the characteristics of narrow and broadband mixing.

[0064] To solve the above problems, this application provides a noise reduction component that can adaptively adjust the position of the floating plate according to actual usage requirements, so that the volume of the first noise reduction cavity changes accordingly, enabling the noise reduction component to adapt to the noise reduction of sound waves with different frequencies, with a wider range of adaptable sound wave frequencies, and there will be no problem of being unable to adapt to the noise reduction of specific frequency sound waves due to processing errors. At the same time, it can also reduce the requirements for processing accuracy of the noise reduction component, reducing the processing difficulty and processing cost.

[0065] It should be noted that the noise reduction component of the present application can be applied not only to mufflers, but also to other environments that require noise reduction. And the muffler using this noise reduction component can be used not only for vehicles, but also for other devices with similar noise reduction requirements.

[0066] The technical solution of the present application and how the technical solution of the present application solves the above technical problems will be described in detail below with specific embodiments. These several specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below with reference to the drawings.

[0067] An embodiment of the present application provides a noise reduction component 100. Please refer to Figure 1 and Figure 2 As shown, the noise reduction component 100 includes an annular baffle 120, an annular housing 110, a floating plate 140, and an adjusting member 150.

[0068] The annular baffle 120 can be a structure with a closed head and tail bent into common shapes such as a circle, an ellipse, or a polygon. A first channel 160 is formed inside it, and a first through hole 130 penetrating the annular baffle 120 is also provided on the annular baffle 120. The annular housing 110 is sleeved outside the annular baffle 120 and connected to the annular baffle 120. The cross-section of the annular housing 110 can be a common structure such as an ellipse, a circle, or a polygon, as long as there is a through hole in the middle and it can be sleeved outside the annular baffle 120. A first cavity 111 is provided on the annular housing 110, and the first cavity 111 can be communicated with the first channel 160 through the first through hole 130. The floating plate 140 is located in the first cavity 111 and partitions a first noise reduction cavity 1111 separated from other parts of the first cavity 111 in the first cavity 111, that is, the floating plate 140 isolates a partial area of the first cavity 111 to form the first noise reduction cavity 1111. The first through hole 130 communicates the first noise reduction cavity 1111 and the first channel 160. At the same time, the floating plate 140 can be controlled by the adjusting member 150 to move in the first cavity 111 to change the volume of the first noise reduction cavity 1111.

[0069] Among them, the first cavity 111 can be a cavity with an opening on the side adjacent to the annular baffle 120. At this time, the annular baffle 120 closes the opening side of the first cavity 111. The first cavity 111 can also be a fully enclosed cavity, and only a hole corresponding to the first through hole 130 is opened on the side adjacent to the annular baffle 120, and it is communicated with the first through hole 130 through this hole.

[0070] Among them, the floating plate 140 has the following two arrangement modes in the first cavity 111:

[0071] Exemplarily, both the annular housing 110 and the annular baffle 120 are alongFigure 2 extends in the X direction, and the first cavity 111 is arranged as a rectangular cavity. The floating plate 140 also extends in the X direction and is adapted to the shape of the first cavity 111. It can move in the direction close to or away from the annular baffle 120 under the drive of the adjusting member 150, that is, move in the Y direction. At this time, the first through hole 130 can be arranged at any position of the annular baffle 120, as long as one end can communicate with the first cavity 111 and the other end can communicate with the first air duct.

[0072] Exemplarily, the floating plate 140 extends along Figure 2 the Y direction in it and is adapted to the shape of the first cavity 111. For example, the first cavity 111 is arranged as an annular shape, and the floating plate 140 is also arranged as an annular plate. The floating plate 140 can move in the X direction under the drive of the adjusting member 150 to change the volume of the first noise reduction cavity 1111. At this time, the first through hole 130 can be arranged as close as possible to one end of the annular baffle 120 to increase the adjustable range of the volume of the first noise reduction cavity 1111 and adapt to the noise reduction of sound waves in a wider frequency band.

[0073] Of course, the first floating plate 140 can also be arranged at other angles with the X or Y direction, as long as it can separate an independent first noise reduction cavity 1111 communicating with the first through hole 130 in the first cavity 111. This embodiment does not limit it here.

[0074] And the number of the first through holes 130 corresponding to each first noise reduction cavity 1111 can be one or more, which can be specifically determined according to the actual situation.

[0075] For the convenience of understanding, the noise reduction principle of the noise reduction component 100 is described in detail below:

[0076] The resonance absorption frequency of the noise reduction component can be expressed by the following formula:

[0077]

[0078] Where c is the speed of sound, S is the cross-sectional area of the first through hole 130, is the length of the first through hole 130, d is the radius of the first through hole 130, and v is the volume of the first noise reduction cavity 1111. By moving the position of the floating plate 140, according to the above formula, it is equivalent to that the volume of the first noise reduction cavity 1111 becomes smaller, and its resonance frequency is higher. The adjustable range of the sound waves adapted by the noise reduction component 100 is related to the variable volume of the first noise reduction cavity 1111.

[0079] According to the sound-electric analogy method, for each first noise reduction cavity 1111, the first through hole 130 connects the first noise reduction cavity 1111 and the first channel 160, and the impedance of the first through hole 130 is:

[0080]

[0081] In the formula, and are the mass density of air and the speed of sound in air, respectively; is the cross-sectional area of the annular baffle 120 in a section perpendicular to its axial direction; is the complex wave number considering the thermo-viscous effect inside the annular baffle 120; is the length of the annular baffle 120; is the specific heat ratio of air; is the thermal field function of the annular baffle 120; is the viscous field function of the annular baffle 120; is the diameter of the annular baffle 120; and are the viscous wave number and the thermal wave number of the annular baffle 120, respectively; ; ; is the noise frequency; is the dynamic viscosity coefficient; is the specific heat at constant pressure; is the thermal conductivity of air; is the end correction length of the annular baffle 120.

[0082] The impedance of the first noise reduction cavity 1111 is:

[0083]

[0084] In the formula, is the volume of the first noise reduction cavity 1111; is the equivalent mass density of the air inside the first noise reduction cavity 1111 considering the thermo-viscous effect; is the equivalent speed of sound inside the first noise reduction cavity 1111; is the equivalent wave number inside the first noise reduction cavity 1111; and are the thermal field function and the viscous field function inside the first noise reduction cavity 1111, respectively; is the diameter of the equivalent circle of the rectangular cross-section inside the first noise reduction cavity 1111; and are the viscous wave number and the thermal wave number inside the first noise reduction cavity 1111, respectively.

[0085] The overall impedance of the noise reduction component 100 is:

[0086]

[0087] Then the transfer equation is as follows:

[0088]

[0089] Wherein, in the formula: is the acoustic transfer matrix of the noise reduction component. The acoustic transfer matrix (T) decomposes a complex pipeline system into several units, and uses four matrix parameters ( ) to describe the corresponding relationship between the sound pressure p and the volume velocity U at both ends of each four-terminal network unit. The transfer matrix of the entire system is obtained by means of matrix operations of series and parallel connections of four-terminal networks. Finally, the acoustic characteristics of the entire system are discussed based on the total transfer matrix. Among them, , , , .

[0090] Then, the transmittance is:

[0091]

[0092] Then the transmission loss is:

[0093]

[0094] It can be seen from this that during use, according to the frequency of the sound wave to be noise-reduced that needs to be noise-reduced, the position of the floating plate 140 can be adjusted by adjusting the component 150, so that the volume of the first noise reduction cavity 1111 changes to make the natural resonance frequency of the noise reduction component 100 close to the frequency of the sound wave to be noise-reduced. At this time, after the sound wave enters the first channel 160, it will enter the first noise reduction cavity 1111 through the first through hole 130, and cause the vibration of the air column in the first through hole 130, thereby causing the gas in the first noise reduction cavity 1111 to resonate, resulting in the energy of the sound wave being exchanged back and forth between the first noise reducer and the first through hole 130, so that the energy of the sound wave is consumed, effectively reducing the noise. This enables the noise reduction component 100 to be adaptively adjusted according to different noises during actual use, broadening the adaptation range of the noise reduction component 100 and enabling it to be used in a more complex noise environment.

[0095] In addition, compared with traditional acoustic metamaterials, the noise reduction component 100 is also more convenient to process. The processing errors, theoretical model errors, etc. can be eliminated by moving the floating plate 140, which can effectively reduce the processing cost.

[0096] Specifically, it can be seen from the above principle description that the smaller the target sound wave frequency, the larger the volume of the first noise reduction cavity 1111. Therefore, during processing, the volume of the first cavity 111 can be adaptively increased according to the frequency of the sound wave to be targeted for noise reduction. For example, if the frequency to be targeted for noise reduction is 152Hz, then it can be designed according to the lowest sound wave of 148Hz. At this time, even if there is an error in the size of the first cavity 111, it is slightly smaller than the volume corresponding to 148Hz. It only needs to adjust the position of the floating plate 140 to cover the sound wave of 152Hz, which can increase the fault tolerance of processing.

[0097] However, if traditional acoustic metamaterials are to target 152Hz sound waves, they can only be processed according to 152Hz. Once the error is slightly larger, it will cause the sound insulation peak to shift, and the 152Hz sound waves will no longer be effectively reduced.

[0098] In addition, in the actual processing process, the shapes of the annular baffle 120 and the annular shell 110 can be adapted, the first cavity 111 is an annular cavity adapted to the shapes of the annular shell 110 and the annular baffle 120, and the floating plate 140 is an annular plate, and moves in the first cavity 111 along the X direction, that is, the moving direction of the floating plate 140 is the same as the extension direction of the annular baffle 120, so that the volume of the first cavity 111 can be expanded as much as possible, thereby expanding the maximum volume of the first noise reduction cavity 1111, so that the noise reduction component 100 can adapt to the noise reduction needs of lower frequency sound waves without making the volume too large.

[0099] In order to characterize the noise reduction effect of the noise reduction component 100, the noise reduction effect of the noise reduction component 100 is tested when the floating plate 140 is in different positions:

[0100] This experiment is mainly used to simulate the low-frequency noise processing of vehicle exhaust pipes. Figure 12 is the vehicle exhaust noise spectrum, such as Figure 12 As shown, the vehicle exhaust noise has an obvious ultra-low frequency periodic noise. This test mainly uses the noise reduction component 100 to process this part of the noise.

[0101] The annular shell 110 used in the test is annular, and the first cavity 111, the annular baffle 120 and the floating plate 140 are also annular, wherein the inner diameter of the annular baffle 120 is 1150 mm, the outer diameter of the annular shell 110 is 1452 mm, the height of the annular shell 110 (the length in the X direction) is 202 mm, the wall thickness of the annular baffle 120 and the annular shell 110 is 1.5 mm, the thickness of the annular baffle 120 is 1.5 mm, the first through hole 130 is a circular hole, the inner diameter of the first through hole 130 is 80 mm, and the depth of the first through hole 130 is 10 mm.

[0102] For a vehicle exhaust pipe, the transmission loss is only related to the structure and is not affected by the source impedance and the radiation characteristics of the tail pipe. It is the most commonly used evaluation index for the acoustic performance of a muffler. When the inlet and outlet of the pipe where the noise reduction component 100 is placed satisfy the plane wave condition, its transmission loss can be expressed as:

[0103]

[0104] where is the incident sound pressure at the inlet of the structure, is the radiated sound pressure at the outlet of the structure, is the area at the inlet of the structure, is the area at the outlet of the structure.

[0105] Through the pressure acoustics module of the multi-physics simulation software COMSOL Multiphysics®, a simulation experiment on the acoustic performance is carried out. First, a straight pipe for placing the noise reduction component 100 is constructed. A pressure boundary condition is applied at one end of the straight pipe, and the noise frequency is controlled according to the noise spectrum of the exhaust pipe in Figure 1 . Since there is intense vibration of the air in the first through hole 130, its heat loss needs to be considered. Therefore, the corresponding area is set as "narrow area acoustics" (this module considers the heat loss and the process of sound energy conversion into heat energy). By performing a frequency domain analysis and obtaining the areas and corresponding pressures at the inlet and outlet of the straight pipe, the transmission loss of the noise reduction component 100 at different frequencies can be obtained according to the above formula.

[0106] Among them, when performing the simulation experiment, the floating plate 140 is successively moved 0.01 m, 0.02 m, 0.03 m, and 0.04 m, so that the volume of the first noise reduction cavity 1111 decreases successively. The specific results of the simulation experiment are as shown in Figure 13 . Figure 13 In the figure, the ordinate TL is the transmission loss.

[0107] From Figure 13 , it can be seen that after moving the floating plate 140, the smaller the volume of the first noise reduction cavity 1111, the larger the corresponding noise frequency, and at each different position, it can play a good noise reduction role for the noise of a specific frequency.

[0108] When each noise reduction component 100 is used alone, it can process noises of different frequencies. If it is desired to process noises of multiple different frequencies, multiple noise reduction components 100 can be connected in series. That is, when the noise reduction component 100 is applied, at least two can be arranged along the moving direction of the sound wave. The first channels 160 of at least two noise reduction components 100 are connected to each other. That is, the inlet end of the first channel 160 of one noise reduction component 100 is connected to the outlet end of the second channel, and the other noise reduction components 100 are connected in sequence along the transmission direction of the sound wave.

[0109] The transmission loss when two noise reduction components 100 are used in series is measured through experiments. During the measurement, by adjusting the position of the floating baffle, the two noise reduction components 100 are corresponding to two different frequencies of noise. The measurement results are as Figure 14 shown. Figure 14 In the figure, the vertical coordinate TL is the transmission loss. It can be seen from this figure that when two noise reduction components 100 are used in series, it does not affect the noise reduction effect of a single noise reduction component 100.

[0110] In some embodiments, the noise reduction component 100 further includes a microphone, which is located at the outlet end of the first channel 160, and is used to measure the real-time sound pressure level at the outlet end of the first channel 160.

[0111] Among them, the sound pressure level is an index to measure the intensity of sound waves, usually expressed in decibels (dB). The microphone is also called a microphone, which can convert sound waves into electrical signals. During the use of the noise reduction component 100, the diaphragm of the microphone receives sound waves and vibrates. The vibration of the diaphragm is converted into an electrical signal through the conversion mechanism of the microphone. The conversion mechanism of the microphone varies according to the type of microphone. For example, the conversion mechanism of a capacitive microphone is capacitance change, and the conversion mechanism of an electromagnetic microphone is electromagnetic induction. It can be specifically selected according to the actual situation, and this embodiment does not limit it here. The converted electrical signal is amplified and processed, such as filtered and calibrated, and then the sound pressure level is calculated to obtain the real-time sound pressure level.

[0112] The real-time sound pressure level can reflect the intensity of sound waves at the outlet end of the first channel 160. At this time, the position of the floating plate 140 can be adjusted through the adjusting member 150 according to the real-time sound pressure level, and the volume of the first noise reduction cavity 1111 can be changed. When the real-time sound pressure level drops and the derivative of the drop value is zero, the position of the floating plate 140 is the best, and noise reduction can be effectively carried out.

[0113] Among them, for the adjusting member 150, it includes but is not limited to the following two structures:

[0114] Exemplarily, the adjusting member 150 includes a driving motor, and the output end of the driving motor is connected to the floating plate 140. The driving motor is used to adjust the position of the floating plate 140 according to the real-time sound pressure level.

[0115] The driving motor can be a linear motor, and its output end is directly connected to one side of the floating plate 140 to drive the floating plate 140 to move in the corresponding direction. At this time, the driving motor can be fixed on the annular housing 110 or fixed on the frame of the structure using the noise reduction component 100, as long as the driving motor will not shift.

[0116] The driving motor can also be a rotating motor. In this case, a screw rod or a rack structure can be added in the first cavity 111 to assist the movement of the floating plate 140. Taking the screw rod as an example, the screw rod can pass through the floating plate 140 and be threadedly connected to the floating plate 140. The driving motor drives the screw rod to rotate, so that the floating plate 140 moves in the first cavity 111 along the extension direction of the screw rod, thereby changing the volume of the first noise reduction cavity 1111.

[0117] When the driving motor is used to drive the floating plate 140 to move, the driving motor and the microphone can be linked to achieve automatic adjustment of the position of the floating plate 140, improve the timeliness of the response of the floating plate 140, and effectively improve the noise reduction effect.

[0118] The linkage between the driving motor and the microphone can be controlled by adding a controller, or by using a controller provided in the device using the noise reduction component 100. The specific control logic is well known to those skilled in the art and will not be described in detail in this embodiment.

[0119] For example, see Figure 1 , Figure 2 and Figure 3 As shown, the adjusting component 150 includes a screw 151, which is fixed on the annular shell 110 and at least partially extends into the first cavity 111. The floating plate 140 is sleeved on the screw 151 and can slide relative to the screw 151. The screw 151 is provided with two positioning blocks 152 threadedly connected to the screw 151. The two positioning blocks 152 are respectively arranged on both sides of the floating plate 140 and abut against the surface of the floating plate 140. The two positioning blocks 152 can be screwed to move the positioning blocks 152 along the length direction of the screw 151, so that the floating plate 140 can be moved along the extension direction of the screw 151 to adjust the position of the floating plate 140 in the first cavity 111.

[0120] It should be noted that the extending direction of the screw rod 151 coincides with the moving track of the floating plate 140 . For example, when the floating plate 140 is an annular plate, the screw rod 151 extends along the X direction.

[0121] In order to effectively support the floating plate 140 and limit the moving direction of the floating plate 140 , two or more screws 151 may be arranged side by side in the first cavity 111 . The specific number may be determined according to actual conditions and is not limited in this embodiment.

[0122] In some embodiments, see Figure 1 and Figure 3As shown, at least one side of the annular baffle 120 is provided with an annular protrusion 131. The annular protrusion 131 extends into the first cavity 111 or the first channel 160. A second through hole penetrating the annular protrusion 131 is provided on the annular protrusion 131, and the second through hole communicates with the first through hole 130.

[0123] Exemplarily, annular protrusions 131 can be provided on both sides of the annular baffle 120 corresponding to the first through hole 130, so that the second through hole is opposite to and communicates with the first through hole 130. This way can increase the length of the through hole connecting the first noise reduction cavity 1111 and the first channel 160. The longer the length of this through hole, the lower the sound wave frequency that can be targeted. This setting method can lower the lower limit of the sound wave frequency that the noise reduction component 100 can target without increasing the volume of the first cavity 111, that is, it can improve the ability to process low-frequency noise as much as possible without increasing the volume of the noise reduction component 100 as much as possible.

[0124] It should be noted that the annular protrusion 131 can also be provided only on one side of the annular baffle 120. When provided only on one side, it can be selectively provided on the side of the annular baffle 120 adjacent to the first cavity 111, that is, the annular protrusion 131 extends into the first cavity 111. This way can not affect the medium flow of the sound wave transmitted in the first channel 160 and avoid introducing new noise.

[0125] In some embodiments, at least one end of the annular baffle 120 can also have a mounting portion 170 extending outside the annular housing 110, that is, the length of the annular baffle 120 is greater than the length of the annular housing 110. In this way, when the noise reduction component 100 is applied to devices such as mufflers, it can be directly assembled with other components through the mounting portion 170 to reduce the installation difficulty.

[0126] It should be noted that the connection method between the mounting portion 170 and other components can be selected according to the actual situation, such as common methods like threads and bolts. This embodiment does not limit it here.

[0127] The embodiment of the present application also provides a muffler. Please refer to Figure 4 、 Figure 5 、 Figure 6 and Figure 7 As shown, it includes a conduction member 200 and the noise reduction component 100 in the above embodiment. A second channel is provided on the conduction member 200, and the inlet end of the first channel 160 communicates with the outlet end of the second channel.

[0128] Specifically, the inlet end of the conduction member 200 is connected to the component generating noise. The conduction member 200 is mainly used to guide the sound wave into the first channel 160 of the noise reduction component 100 for noise reduction through the noise reduction component 100.

[0129] Taking a car as an example, the conductive member 200 can be connected to the end of the exhaust pipe or a position close to the end of the exhaust pipe to conduct the noise generated by the operation of the fan. Of course, the conductive member 200 can also be directly the exhaust pipe of the vehicle to reduce the number of parts.

[0130] Different noise reduction components 100 can be used for noises in different frequency bands. Therefore, two, three or more noise reduction components 100 can be provided. The specific configuration can be made according to the characteristics of the noise, and this embodiment does not limit this.

[0131] When at least two noise reduction components 100 are provided, the volumes of the first cavities 111 of the noise reduction components may be the same or different. Taking the provision of two noise reduction components 100 as an example, there are the following two provision methods:

[0132] First, the two noise reduction components 100 have the same structure, that is, the volume of the first cavity 111 is the same. During use, the floating plates 140 of the two noise reduction components 100 can be located at different positions in the first cavity 111, so that the two noise reduction components 100 can target noise in different frequency bands.

[0133] Second, the structures of the two noise reduction components 100 are different, so that the adjustable ranges of the volumes of the first noise reduction chambers 1111 of the two noise reduction components 100 are different, thereby increasing the adaptable noise frequency band range.

[0134] In the actual application of the muffler, the noise may include a variety of different frequency bands with a large span. For example, the exhaust pipe of a car Figure 12 As shown in , it includes ultra-low frequency periodic noise less than 200 Hz caused by the rotation of fan blades ( Figure 12 The area in the left box in the middle), the turbulent noise of 300Hz-1000Hz generated by the interaction between gas and solid and the airflow itself ( Figure 12 The area in the middle right frame) is relatively complex in composition, and it is difficult to perform noise reduction only through the noise reduction component 100.

[0135] In this regard, the silencer may further include a sound absorbing component 300, the sound absorbing component 300 being located between the noise reduction component 100 and the conductive component 200, or the sound absorbing component 300 being located on the side of the noise reduction component 100 away from the conductive component 200, and the frequency corresponding to the noise in the sound waves processed by the sound absorbing component 300 is greater than the frequency corresponding to the noise in the sound waves processed by the noise reduction component 100.

[0136] Specifically, see Figure 8 , Figure 9 , Figure 10 and Figure 11As shown, the sound absorption component 300 includes a housing 310 and a first sound absorption member 330. A third channel 320 is provided inside the housing 310, and the third channel 320 communicates with the first channel 160. The housing 310 can be set to a prismatic shape, a cylindrical shape, an elliptical cylindrical shape, or any other shape, as long as it has the third channel 320 inside.

[0137] The first sound absorption member 330 is located inside the third channel 320. A plurality of second noise reduction cavities 336 are provided on the first sound absorption member 330, and the plurality of second noise reduction cavities 336 have at least two different volumes; a plurality of third through holes 333 are also provided on the first sound absorption member 330, and each second noise reduction cavity 336 communicates with the third channel 320 through at least one third through hole 333.

[0138] Exemplarily, the first sound absorption member 330 is located at one end of the noise reduction component 100 away from the conduction member 200. The outlet end of the first channel 160 of the noise reduction component 100 adjacent to the housing 310 communicates with the third channel 320. The first sound absorption member 330 processes the noise processed by the noise reduction component 100. The first sound absorption member 330 can also be located between the noise reduction component 100 and the conduction member 200. The inlet end of the third channel 320 communicates with the outlet end of the second channel, and the inlet end of the first channel 160 of the noise reduction component 100 adjacent to the housing 310 communicates with the outlet end of the third channel 320. The first sound absorption member 330 first processes the noise in a specific frequency band, and then the noise reduction component 100 performs subsequent processing on the remaining frequency band of the noise.

[0139] The first sound absorption member 330 may include a main body member. A plurality of second noise reduction cavities 336 are provided on at least one side of the main body member. The second noise reduction cavities 336 can be circular, elliptical, rectangular, or other shapes. The volumes of the plurality of second noise reduction cavities 336 are different from each other, or some are the same and some are different. When the sound waves in the third channel 320 enter the second noise reduction cavities 336 through the third through holes 333, the second noise reduction cavities 336 with different volumes can resonate with sound waves in different frequency bands, reducing the noise energy corresponding to the frequency bands. Thus, the first sound absorption member 330 can process noises in a plurality of different frequency bands, expanding the frequency band of the noise that can be processed.

[0140] Among them, the first cavity 111 of the noise reduction component 100 can be set to a ring shape with a relatively large volume, which can process the noise in a lower frequency band. The first sound absorption member 330 can be provided with second noise reduction cavities 336 with relatively small volumes to process the noise in a slightly higher frequency band. Thus, not only can the volume of the muffler be reduced, but also the noise in different frequency bands can be processed.

[0141] It should be noted that if only the first sound absorption component 330 is provided, then for the noise in the ultra-low frequency band, it is required that the volume of the second noise reduction cavity 336 is relatively large, which will result in a relatively large volume of the first sound absorption component 330, thereby greatly increasing the volume of the muffler and restricting the scenarios where the muffler can be used. Therefore, the noise reduction assembly 100 and the first sound absorption component 330 are used in combination. Each of them is targeted at different noises, which can effectively reduce the overall volume of the muffler and help reduce costs.

[0142] Further, please refer to Figure 9 , Figure 10 and Figure 11 As shown, the volume of the second noise reduction cavity 336 decreases or increases successively along the moving direction of the sound wave in the third channel 320. For example, it increases successively along the arrow direction in Figure 9 .

[0143] Specifically, when the effective area for the fluid to pass through the third through-hole 333 remains unchanged, the larger the volume of the second noise reduction cavity 336, the lower the corresponding frequency of the sound wave. Figure 11 The arrangement of the second noise reduction cavity 336 in Figure 9 is the same as that in Figure 9 , both as indicated by the arrow direction in

[0144] . The frequencies corresponding to the second noise reduction cavity 336 decrease successively, and the size of the second noise reduction cavity 336 increases or decreases successively along the moving direction of the sound wave, so as to process sound waves of different frequencies successively.

[0145] In practical applications, the third channel 320 generally has a certain volume. In order to make full use of this part of the space, a plurality of first sound absorption components 330 can be arranged at intervals successively in the direction perpendicular to the extension direction of the third channel 320, that is, the first sound absorption components 330 are stacked successively along the radial direction of the third channel 320.

[0146] In some embodiments, the first sound absorption component 330 includes a main body component and two cover plates 332. A plurality of cavities are arranged on both opposite sides of the main body component. The two cover plates 332 are respectively covered on both sides of the main body component and enclose the cavities to form the second noise reduction cavity 336. The third through-hole 333 is arranged on the cover plate 332 and penetrates through the cover plate 332 along the thickness direction of the cover plate 332.

[0147] Specifically, the length direction of the main body component is the same as the extension direction of the third channel 320. The cavity is arranged on both sides of the length direction of the main body component. When multiple first sound absorbing components 330 are overlapped, there is a gap between adjacent first sound absorbing components 330. Sound waves can enter the third through holes 333 on adjacent first sound absorbing components 330 through the gap. At this time, there are independent second noise reduction cavities 336 and third through holes 333 on both sides of the main body component, so that there will be no area without third through holes 333 between adjacent first sound absorbing components 330, which can effectively improve the noise reduction effect.

[0148] Furthermore, the main body part includes a middle partition plate 331 and two grid support plates 334. The grid support plates 334 are provided with a plurality of through slots 335, and the two grid support plates 334 are arranged on opposite sides of the middle partition plate 331, so that the middle partition plate 331 closes one end of the through slots 335 to form a cavity; wherein the cover plate 332 is arranged on the side of the grid support plate 334 away from the middle partition plate 331.

[0149] During assembly, the grid support plate 334 is directly fixed on the middle partition plate 331, and then the cover plate 332 is placed on the grid support plate 334. This not only reduces the difficulty of processing the first sound absorbing component 330, but also the two grid support plates 334 share one middle partition plate 331, which also helps to reduce the volume of the first sound absorbing component 330, reduces the occupied space, and also helps to reduce costs.

[0150] The specific size design of the first sound absorbing component 330 can be determined by the following method:

[0151] First determine the upper and lower frequency limits of the noise that the first sound absorbing component 330 needs to handle. At this time, the minimum and maximum volumes of the second noise reduction cavity 336 can be determined. Because the resonance peak is very sensitive to the volume change of the second cavity at high frequencies, but is insensitive to the volume change of the second cavity at low frequencies, the volume change of the second noise reduction cavity 336 can be made exponential to ensure that the resonance peak is evenly distributed between the upper and lower frequency limits.

[0152] The impedance of the plurality of first sound absorbing components 330 is:

[0153]

[0154] In the formula, is the impedance of the third through hole 333 of the nth first sound absorbing member 330, is the impedance of the second noise reduction cavity 336 of the nth first sound absorbing component 330, and its parameters are detailed in the calculation method of the impedance of the first noise reduction cavity 1111 and the impedance of the first through hole 130 in the noise reduction component 100 in the above embodiment. Then, the transfer equation is:

[0155]

[0156] Wherein: 。

[0157] Then the transmittance of multiple first sound absorption components 330 is:

[0158]

[0159] Then the transmission loss of multiple first sound absorption components 330 is:

[0160]

[0161] The transfer equation for the combined use of multiple first sound absorption components 330 and the noise reduction component 100 is:

[0162]

[0163] Wherein: is the acoustic transfer matrix of the noise reduction component 100, is the acoustic transfer matrix of the first sound absorption component 330.

[0164] Then the transmittance when multiple first sound absorption components 330 and the noise reduction component 100 are combined for use is:

[0165]

[0166] Where d is the sum of the lengths of the first noise reduction component 100 and the first sound absorption component 330 along the noise transmission direction, then the transmission loss is:

[0167]

[0168] For the sake of easy understanding, some further illustrative examples of the structure of the first sound absorption component 330 are given below:

[0169] Exemplarily, the structures of the two grid support plates 334 are the same, that is, the through slots 335 on the two grid support plates 334 are arranged in one-to-one correspondence, and the shapes of the corresponding through slots 335 are the same. However, the effective areas for the fluid to pass through the third through holes 333 on the two cover plates 332 are different. That is, the third through holes 333 can be set in any shape, such as circular, elliptical, rectangular or other shapes. The sizes of the third through holes 333 on a single cover plate 332, that is, the effective areas for the fluid to pass through, are the same, while the sizes of the third through holes 333 provided on the two cover plates 332 are different. On one side of the first sound absorption component 330, only the size of the second noise reduction cavity 336 changes sequentially along the sound wave moving direction. The larger the third noise reduction cavity, the lower the frequency, which can be targeted at noises of different frequencies. For the two second noise reduction cavities 336 corresponding to the two sides of the middle partition plate 331, the inner diameters of the corresponding third through holes 333 are different. The smaller the third through hole 333, the lower the corresponding frequency, so that the third noise reduction cavities on both sides of the middle partition plate 331 can be targeted at noises of different frequencies, and this setting method has a better effect on the noise processing of a specific frequency band.

[0170] Exemplarily, the sizes of the through slots 335 on the same grid support plate 334 are different from each other, and the sizes of the through slots 335 on the two grid support plates 334 are also different. The inner diameters of the third through holes 333 on the same cover plate 332 are different, which can increase the frequency band of the noises that the first sound absorption component 330 can process. However, the frequency bands targeted by each third noise reduction cavity are relatively scattered, and the noise processing effect for a specific frequency band may be slightly worse.

[0171] It should be noted that the above is only an example and not a limitation. The sizes of the through slots 335 on the grid support plate 334 and the inner diameters of the third through holes 333 on the cover plate 332 can be adjusted according to a certain rule, or only one of them can be changed while the other remains unchanged, or both of them can be changed randomly. This embodiment does not limit it here.

[0172] In addition, in actual production, the shape of the third channel 320 may not be rectangular, but circular or elliptical and other structures. Taking the circular shape as an example, at this time, the inner diameter of the third channel 320 decreases from the middle to both sides, and the corresponding size of the first sound absorption component 330 will also decrease sequentially. At this time, in the width direction of the first sound absorption component 330, the number of through slots 335 can be increased on the grid support plate 334 corresponding to the first sound absorption component 330 with a larger size, and the number of through slots 335 can be reduced on the grid support plate 334 with a smaller size.

[0173] In some embodiments, the sound absorption component 300 further includes a second sound absorption member 340 located in the third channel 320. The second sound absorption member 340 is located at the inlet end or the outlet end of the first sound absorption member 330. The frequency of the noise in the sound wave processed by the second sound absorption member 340 is greater than the frequency of the noise in the sound wave processed by the first sound absorption member 330.

[0174] When the first sound absorption member 330, the second sound absorption member 340 and the noise reduction component 100 are used in combination, the volume of the first noise reduction cavity 1111 of the noise reduction component 100 is adjustable and can be used to process special single-frequency noise, such as the noise peak generated at different rotational speeds when the fan is running. The first sound absorption member 330 and the second sound absorption member 340 can cooperate together to process the noise of the interaction between gas and solid and the turbulence noise of the air flow itself, so as to adapt to the processing of common wide and narrow band mixed noise.

[0175] Further, the second sound absorption member 340 includes a plurality of sound insulation cotton sheets arranged at intervals in sequence along the direction perpendicular to the extension direction of the third channel 320, that is, stacked along the radial direction of the third channel 320.

[0176] Specifically, the stacking direction of the sound insulation cotton sheets is the same as the stacking direction of the first sound absorption member 330, and the gap between adjacent sound insulation cotton sheets corresponds to the gap between adjacent first sound absorption members 330, so that the sound wave can move effectively between the two.

[0177] In order to characterize the effects of the first sound absorption member 330 and the second sound absorption member 340 during use, the following tests were conducted on the effects of the first sound absorption member 330 and the second sound absorption member 340 used alone and in combination on noise processing:

[0178] Ten first sound absorption members 330 and ten sound insulation cotton sheets were used in the test. Both are stacked in sequence along the radial direction of the third channel 320, and the gap between adjacent two first sound absorption members 330 is the same and opposite to the gap between adjacent two sound insulation cotton sheets.

[0179] The size of the sound insulation cotton sheet is 782.9mm 50mm 1674 mm, where the side with a length of 782.9mm is the side parallel to the noise transmission direction, and the gap width between adjacent sound insulation cotton sheets is 175mm;

[0180] The size of the first sound absorption member 330 is 727.1mm 50mm 1674 mm, where the side with a length of 727.1 mm is the side parallel to the noise transmission direction, and the gap width between adjacent sound insulation cotton sheets is 175 mm. The thicknesses of the middle partition 331 and the cover plate 332 are both 1 mm, and the thickness of the grid support plate 334 is 23.5 mm, that is, the height of the second noise reduction cavity 336 is 23.5 mm.

[0181] The second noise reduction cavity 336 is a rectangular cavity. For the same first sound absorption component 330, on one side of the middle partition 331, corresponding to the side with a length of 727.1, 15 columns of second noise reduction cavities 336 are provided, and corresponding to the side with a length of 1674 mm, 27 rows of second noise reduction cavities 336 are provided (the sizes of multiple second noise reduction cavities 336 in each row are different), that is, a total of 810 second noise reduction cavities 336 are provided for each first sound absorption component 330. In the direction parallel to the noise transmission direction, multiple second noise reduction cavities 336 are sequentially sorted from 1 - 15, and their lengths and widths change in sequence according to Table 1:

[0182] Table 1

[0183]

[0184] Among them, the length is the length of the second noise reduction cavity 336 along the side extending in the noise transmission direction. The third through holes 333 on both cover plates 332 are all round holes, and the inner diameter of the third through hole 333 on one cover plate 332 is 6 mm, and the inner diameter of the third through hole 333 on the other cover plate 332 is 16 mm. Each second noise reduction cavity 336 corresponds to one third through hole 333.

[0185] Use the pressure acoustics module of the multi - physical simulation software COMSOL Multiphysics® software to conduct acoustic performance simulation experiments. First, construct a straight pipeline, and then construct the first sound absorption component 330 and / or sound insulation cotton sheets in the straight pipeline according to the test requirements. Apply a pressure boundary condition at one end of the straight pipeline, and control the input noise frequency according to the noise spectrum of the exhaust pipe in Figure 1 . Since there is violent vibration of the air in the third through hole 333, its heat loss needs to be considered. Therefore, the corresponding area is set as "narrow - region acoustics" (this module considers the heat loss and the process of sound energy conversion into heat energy). The sound insulation cotton sheet area is set as porous medium acoustics, and nine parameters are used to describe the heat loss of the cotton sheet area. Conduct frequency - domain analysis to obtain the areas and corresponding pressures at the inlet and outlet of the straight pipeline, and then the transmission loss at different frequencies can be obtained according to the transmission loss formula used in the simulation experiment of the noise reduction component 100.

[0186] The results of the simulation test are as Figure 15 shown, from Figure 15It can be seen that when only ten first sound-absorbing components 330 are used alone, only low-frequency noise within 500 - 1000 Hz can be processed. When only ten sound-insulating cotton sheets are used alone, only high-frequency noise can be processed. When the first sound-absorbing component 330 and the second sound-absorbing component 340 are used in combination, better noise processing effects can be achieved for noise in both frequency ranges. It can also be seen that the second sound-absorbing component 340 has a more than 2 dB improvement on the action area of the first sound-absorbing component 330, but it does not affect the frequency band position where the first sound-absorbing component 330 acts. Therefore, when the first sound-absorbing component 330 processes low-frequency noise, the influence caused by the second sound-absorbing component 340 does not need to be considered.

[0187] In order to measure the influence of the volume change direction of the second noise reduction cavity 336 of the first sound-absorbing component 330 on noise processing, the first sound-absorbing component 330 was also tested alone.

[0188] Among them, the structures of the first sound-absorbing components 330 used in Example 1 and Example 2 are the same, both being the first sound-absorbing component 330 in the above simulation test. The only difference is that the volume of the second noise reduction cavity 336 in Example 1 decreases successively along the moving direction of the sound wave, while the volume of the second noise reduction cavity 336 of the first sound-absorbing component 330 in Example 2 increases successively along the moving direction of the sound wave. The simulation test results are as Figure 16 shown. It can be seen from Figure 16 that the setting direction of the second noise reduction cavity 336 does not have an obvious influence on the transmission loss.

[0189] In actual applications, the installation positions of the first sound-absorbing component 330, the second sound-absorbing component 340, and the noise reduction component 100 can be adjusted according to the actual situation. However, whether the first sound-absorbing component 330 is adjacent to the noise reduction component 100 or the second sound-absorbing component 340 is adjacent to the noise reduction component 100, it is advisable to maintain a certain gap from the outlet end of the second channel of the noise reduction component 100 to facilitate the sound wave to enter the third channel 320.

[0190] Exemplarily, please refer to Figure 4 and Figure 5 shown. The noise reduction component 100 is connected to the conduction member 200. The second sound-absorbing component 340 is located between the first sound-absorbing component 330 and the noise reduction component 100. The airflow transmitting the sound wave sequentially passes through the noise reduction component 100, the second sound-absorbing component 340, and the first sound-absorbing component 330, and finally leaves the muffler from the outlet end of the third channel 320.

[0191] Exemplarily, as Figure 11 shown, the noise reduction component 100 is connected to the conduction member 200, and the first sound-absorbing component 330 is located between the noise reduction component 100 and the second sound-absorbing component 340.

[0192] Exemplarily, as Figure 7 shown, two or more noise reduction components 100 are sequentially arranged, and the first channels 160 of each other are connected in series. The noise reduction component 100 adjacent to the conduction member 200 is connected to the conduction member 200. The outlet end of the first channel 160 of the noise reduction component 100 facing away from the conduction member 200 is connected to the third channel 320, and the first sound absorption member 330 is located between the second sound absorption member 340 and the noise reduction component 100 facing away from the conduction member 200.

[0193] Exemplarily, as Figure 6 shown, the inlet end of the third channel 320 of the housing 310 is communicated with the outlet end of the second channel of the conduction member 200. The noise reduction component 100 is connected to one end of the housing 310 facing away from the conduction member 200. The second sound absorption member 340 is adjacent to the conduction member 200, and the first sound absorption member 330 is located between the second sound absorption member 340 and the noise reduction component 100.

[0194] The embodiment of the present application further provides a vehicle, including a vehicle body and the muffler in the above embodiment, and the muffler is installed on the vehicle body.

[0195] Exemplarily, the conduction member 200 of the muffler is an exhaust pipe installed on the vehicle body, or an exhaust pipe is provided on the vehicle body, and the conduction member 200 is connected to the end of the exhaust pipe. The noise generated by the rotation of the fan can be adaptively processed through the muffler, improving the noise reduction effect.

[0196] Finally, it should be noted that: After considering the specification and practicing the invention disclosed here, those skilled in the art will easily think of other implementation schemes of the present invention. The present invention aims to cover any variations, uses or adaptive changes of the present invention. These variations, uses or adaptive changes follow the general principles of the present invention and include the common general knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the precise structure already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A noise reduction component (100), characterized in that: include: an annular baffle (120), wherein a first channel (160) is formed inside the annular baffle (120), and the annular baffle (120) is provided with a first through hole (130) penetrating the annular baffle (120) in a thickness direction; an annular shell (110), wherein the annular shell (110) is sleeved outside the annular baffle (120), and a first cavity (111) is provided inside the annular shell (110); a floating plate (140), the floating plate (140) being located in the first cavity (111), the floating plate (140) cooperating with a cavity wall of the first cavity (111) to isolate at least a portion of the first cavity (111) to form a first noise reduction cavity (1111), and the first through hole (130) being in communication with the first noise reduction cavity (1111); An adjusting component (150), wherein the adjusting component (150) is used to adjust the position of the floating plate (140) in the first cavity (111) so as to adjust the volume of the first noise reduction cavity (1111).

2. The noise reduction assembly (100) according to claim 1, characterized in that: The floating plate (140) is an annular plate, and the moving direction of the floating plate (140) is the same as the extending direction of the annular baffle (120).

3. The noise reduction assembly (100) according to claim 2, characterized in that: The invention also comprises a microphone, which is located at the outlet end of the first channel (160) and is used to measure the real-time sound pressure level at the outlet end of the first channel (160).

4. The noise reduction assembly (100) according to claim 3, characterized in that: The adjusting component (150) comprises a driving motor, the output end of which is connected to the floating plate (140), and the driving motor is used to adjust the position of the floating plate (140) according to the real-time sound pressure level.

5. The noise reduction assembly (100) according to claim 1, characterized in that: The adjusting component (150) comprises a screw rod (151) arranged on the annular shell (110), the screw rod (151) passes through the floating plate (140) and is slidably connected to the floating plate (140), and two positioning blocks (152) threadedly connected to the screw rod (151) are arranged on the screw rod (151), and the two positioning blocks (152) are respectively arranged on both sides of the floating plate (140) and abut against the surface of the floating plate (140) to limit the relative position of the floating plate (140) and the screw rod (151).

6. The noise reduction assembly (100) according to claim 1, characterized in that: At least one of the two sides of the annular baffle (120) in the extension direction is provided with an annular protrusion (131), the annular protrusion (131) extends into the first cavity (111) or the first channel (160), and the annular protrusion (131) is provided with a second through hole penetrating the annular protrusion (131), and the second through hole is connected to the first through hole (130).

7. The noise reduction component (100) according to any one of claims 1 to 6, characterized in that: At least one end of the annular baffle (120) is provided with a mounting portion (170) extending outside the annular housing (110).

8. A muffler, characterized in that: The noise reduction component (100) comprises a conductive member and any one of claims 1 to 7, wherein a second channel is arranged on the conductive member (200), and an inlet end of the first channel (160) is connected to an outlet end of the second channel.

9. The muffler according to claim 8, characterized in that At least two of the noise reduction components (100) are arranged along the moving direction of the sound wave, and the first channels (160) of at least two of the noise reduction components (100) are connected to each other.

10. The muffler according to claim 8, characterized in that The invention also comprises a sound absorbing component (300), wherein the sound absorbing component (300) is located between the noise reduction component (100) and the conductive component (200), or the sound absorbing component (300) is located on a side of the noise reduction component (100) away from the conductive component (200), and the frequency corresponding to the noise in the sound wave processed by the sound absorbing component (300) is greater than the frequency corresponding to the noise in the sound wave processed by the noise reduction component (100).

11. The muffler according to claim 10, characterized in that The sound absorbing component (300) comprises: A housing (310), wherein a third channel (320) is disposed in the housing (310), and the third channel (320) is communicated with the first channel (160); A first sound absorbing component (330), the first sound absorbing component (330) being located in the third channel (320), the first sound absorbing component (330) being provided with a plurality of second noise reduction cavities (336), at least one of the plurality of second noise reduction cavities (336) having a volume different from that of the remaining portions; the first sound absorbing component (330) being further provided with a plurality of third through holes (333), each of the second noise reduction cavities (336) being connected to the third channel (320) via at least one of the third through holes (333).

12. The muffler according to claim 11, characterized in that The volumes of the plurality of second noise reduction chambers (336) decrease or increase in sequence along the moving direction of the sound waves in the third channel (320).

13. The muffler according to claim 11, characterized in that A plurality of the first sound absorbing components (330) are sequentially arranged at intervals along the radial direction of the third channel (320).

14. The muffler according to claim 11, characterized in that The first sound absorbing component (330) comprises: A main body component, wherein a plurality of cavities are arranged on opposite sides of the main body component in the extension direction of the third channel (320); Two cover plates (332), the two cover plates (332) are respectively covered on both sides of the main body component and close the cavity to form the second noise reduction cavity (336), and the third through hole (333) is arranged on the cover plate (332) and penetrates the cover plate (332) along the thickness direction of the cover plate (332).

15. The muffler according to claim 14, characterized in that The main body component comprises: Middle partition (331); Two grid support plates (334), each of which is provided with a plurality of through slots (335), and the two grid support plates (334) are arranged on opposite sides of the middle partition plate (331), so as to form the cavity by closing one end of the through slot (335) through the middle partition plate (331); Wherein, the cover plate (332) is arranged on a side of the grid support plate (334) away from the middle partition plate (331).

16. The muffler according to claim 15, characterized in that The two grid support plates (334) have the same structure, and the effective area of ​​the third through hole (333) on one of the two cover plates (332) is greater than the effective area of ​​the third through hole (333) on the other cover plate.

17. The muffler according to any one of claims 11 to 16, characterized in that: The sound absorbing component (300) further comprises a second sound absorbing component (340) located in the third channel (320), the second sound absorbing component (340) being located at an inlet end or an outlet end of the first sound absorbing component (330), and a frequency corresponding to noise in a sound wave processed by the second sound absorbing component (340) being greater than a frequency corresponding to noise in a sound wave processed by the first sound absorbing component (330).

18. The muffler according to claim 17, characterized in that The second sound absorbing component (340) comprises a plurality of sound insulating cotton sheets which are sequentially arranged at intervals along the radial direction of the third channel (320).

19. A vehicle, characterized in that: The utility model comprises a vehicle body and the muffler according to any one of claims 8 to 18, wherein the muffler is mounted on the vehicle body.

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