Noise reduction component, muffler and vehicle

Abstract

An embodiment of the present application provides a noise reduction component, a muffler and a vehicle, relating to the technical field of sound absorption and noise reduction. The noise reduction component includes: an annular baffle, a first channel is formed on the inner side of the annular baffle, and a first through hole is provided on the annular baffle that penetrates the annular baffle along the thickness direction; an annular shell, the annular shell is sleeved outside the annular baffle, and a first cavity is provided in the annular shell; a floating plate, the floating plate is located in the first cavity, and cooperates with the cavity wall of the first cavity to form a first noise reduction cavity connected to the first through hole; an adjusting component, the 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, so that the noise reduction component can adjust the resonant frequency according to actual conditions to adapt to the noise reduction requirements of sound waves of different frequencies.

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] A 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 their 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 are large errors in product manufacturing, the sound insulation peak will shift significantly, making it impossible to adapt to noise control at specific frequencies. 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 acoustic metamaterials used in existing mufflers cannot adapt to specific frequency noise control if there are large errors in their manufacturing.

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

[0007] an annular baffle, wherein a first channel is formed on the inner side of the annular baffle, and a first through hole is provided on the annular baffle penetrating the annular baffle in a thickness direction;

[0008] an annular shell, the annular shell being sleeved outside the annular baffle, and a first cavity being provided in 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, the adjustment component includes a drive motor, an output end of the drive motor is connected to the floating plate, and the drive 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 provided on the annular shell, the screw passing through the floating plate and being slidingly connected to the floating plate, and two positioning blocks threadedly connected to the screw are provided on the screw, 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.

[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 is provided on the annular protrusion and passes through the annular protrusion, and the second through hole is connected to the first through hole.

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

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

[0018] The noise reduction assembly comprises a conductive member and 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 noise reduction components are connected to each other.

[0020] In a possible embodiment, a sound absorbing component is further included. The sound absorbing component is located between the noise reduction component and the conductive member, or the sound absorbing component is located on a side of the noise reduction component away from the conductive member. 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 housing, wherein a third channel is provided in the housing and the third channel is communicated with the first channel;

[0023] A first sound absorbing component is located in the third channel, and is provided with a plurality of second noise reduction cavities on the first sound absorbing component, wherein at least one of the plurality of second noise reduction cavities has a different volume from the remaining portions; the first sound absorbing component is further provided with a plurality of third through holes, and each second noise reduction cavity 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 cavities 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 and spaced apart 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 provided on 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 one possible implementation, the main body component includes:

[0030] Middle partition;

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

[0034] In a possible embodiment, the sound absorbing assembly further includes a second sound absorbing component located in the third channel, the second sound absorbing component being 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 being greater than a frequency corresponding to noise in sound waves processed by the first sound absorbing component.

[0035] In a possible implementation, the second sound absorbing component includes a plurality of sound insulation cotton sheets sequentially spaced apart along the radial direction of the third channel.

[0036] In a third aspect, an embodiment of the present application provides a vehicle, comprising a vehicle body and the muffler described in any one of the second aspects, wherein the muffler is mounted on the vehicle body.

[0037] In the noise reduction assembly, muffler and vehicle provided in the embodiments of the present application, the noise reduction assembly is provided with an annular baffle, an annular shell, a floating plate and an adjusting component. The annular shell is sleeved on the outside of the annular baffle, and the floating plate is provided in the first cavity on the annular shell and enclosed with the cavity wall of the first cavity to form a first noise reduction cavity. The first through hole provided on the annular baffle connects the first channel inside the annular baffle and the first noise reduction cavity. During use, the position of the floating plate can be adjusted by the adjusting component according to the frequency of the sound wave to be reduced, so that the volume of the first noise reduction cavity changes to a point where the natural resonance frequency of the noise reduction assembly is 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 air column in the first through hole to vibrate, thereby causing the gas in the first noise reduction cavity 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, 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 actual usage needs, so that the noise reduction component can adapt to noise reduction of sound waves of different frequencies. The adaptive sound wave frequency range is wide, and there will be no problem of being unable to adapt to noise reduction of sound waves of specific frequencies due to processing errors. At the same time, it can also reduce the requirements of the noise reduction component for processing accuracy, reduce processing difficulty and processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0039] Figure 1 A schematic diagram of the external structure of the noise reduction component provided in an embodiment of the present application;

[0040] Figure 2 A schematic structural diagram of an implementation scheme of a noise reduction component provided in an embodiment of the present application;

[0041] Figure 3 A schematic structural diagram of another embodiment of the noise reduction component provided in an embodiment of the present application;

[0042] Figure 4 A schematic structural diagram of a first embodiment of a muffler provided in an embodiment of the present application;

[0043] Figure 5A schematic structural diagram of a second embodiment of the muffler provided in an embodiment of the present application;

[0044] Figure 6 A schematic structural diagram of a third embodiment of the muffler provided in an embodiment of the present application;

[0045] Figure 7 A schematic structural diagram of a fourth embodiment of the muffler provided in an embodiment of the present application;

[0046] Figure 8 A schematic structural diagram of a first sound-absorbing component in a muffler provided in an embodiment of the present application;

[0047] Figure 9 A schematic diagram of the change in the resonance frequency of the first sound absorbing component in the muffler provided in an embodiment of the present application;

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

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

[0050] Figure 12 is the exhaust noise spectrum of the vehicle;

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

[0052] Figure 14 A schematic diagram of the transmission loss of the noise reduction component coupling provided in an embodiment of the present application;

[0053] Figure 15 A schematic diagram comparing the transmission losses of the first sound absorbing component and the second sound absorbing component in the muffler provided in an embodiment of the present application;

[0054] Figure 16 This is a structural schematic diagram of the volume change direction of the first noise reduction cavity in the first sound absorbing component in the muffler provided in an embodiment of the present application.

[0055] Reference numerals:

[0056] 100-noise reduction component, 110-annular shell, 111-first cavity, 1111-first noise reduction cavity, 120-annular baffle, 130-first through hole, 131-annular protrusion, 140-floating plate, 150-adjusting component, 151-screw, 152-positioning block, 160-first channel, 170-mounting part, 200-conducting part, 300-sound absorbing component, 310-housing, 320-third channel, 330-first sound absorbing component, 331-middle partition, 332-cover plate, 333-third through hole, 334-grid support plate, 335-through groove, 336-second noise reduction cavity, 340-second sound absorbing component.

[0057] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0058] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0059] First, let’s explain the terms involved in this application:

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

[0061] Noise can be divided into three categories based on its energy distribution: Noise whose energy is distributed over a wide frequency band is called broadband noise, such as broadband random noise such as road structure noise caused by random road excitation; noise whose energy is mainly concentrated in a few frequency components is called narrowband noise, such as engine order noise and other noise generated by the reciprocating motion of rotating equipment. This type of noise has a strong periodic characteristic; noise whose energy is distributed in both a few frequency components and a wide frequency band is called mixed broadband and narrowband noise, of which the medium and low frequency noise inside the car is a typical example.

[0062] However, most of the noise in the actual environment has the characteristics of a mixture of wide and narrow bands. If noise reduction is performed through active noise control technology based on phase cancellation, the following steps are required: Active noise control technology based on phase cancellation mainly cancels noise by generating sound waves that are the same as the noise but with opposite phases. It needs to first detect the noise in the environment and convert these noise signals into electrical signals. Then, it uses the signal processing unit to analyze these noise signals, calculates and emits sound wave signals opposite to these noise signals, and then emits sound waves opposite to the noise sound position through the speaker. This process involves complex algorithms and real-time processing, and it is also necessary to continuously adjust the generated sound waves according to the changes in the noise. The composition of noise with wide and narrow band mixing characteristics is extremely complex, which leads to the problems of high price and non-convergence of the algorithm when active noise control technology based on phase cancellation is applied to this environment.

[0063] In response to this, a number of acoustic metamaterials have emerged in recent years, offering acoustic properties that surpass those of natural materials. For example, thin-film metamaterials can significantly reduce the thickness and mass density of sound-isolating structures. However, these technologies require the insertion of natural or artificial materials, limiting their ventilation capabilities. Furthermore, the structural units of acoustic metamaterials are mostly passive; once formed, their material properties are fixed and cannot be altered. Acoustic metamaterials are also extremely sensitive to structural dimensions. Significant errors in product manufacturing can significantly shift the peak sound insulation value. These limitations significantly limit the development of acoustic metamaterials. Consequently, there is an urgent need for acoustic metamaterials with flexible material properties and operating frequency bands to adapt to noise reduction with mixed wide- and narrow-band characteristics.

[0064] In order to solve the above problems, the present application provides a noise reduction component, which 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, so that the noise reduction component can adapt to sound wave noise reduction of different frequencies, and the adapted sound wave frequency range is wider, and there will be no problem of being unable to adapt to specific frequency sound wave noise reduction due to processing errors. At the same time, it can also reduce the noise reduction component's requirements for processing accuracy, reduce processing difficulty and processing costs.

[0065] It should be noted that the noise reduction assembly of the present application can be used not only in mufflers, but also in other environments requiring noise reduction. The muffler using the noise reduction assembly can also be used not only in vehicles, but also in other equipment with similar noise reduction requirements.

[0066] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments 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 in conjunction with the accompanying drawings.

[0067] The present application embodiment provides a noise reduction component 100, see Figure 1 and Figure 2 As shown, the noise reduction assembly 100 includes an annular baffle 120 , an annular housing 110 , a floating plate 140 , and an adjustment member 150 .

[0068] The annular baffle 120 can be a closed-end structure bent into a common shape, such as a circle, ellipse, or polygon. A first passage 160 is formed on its inner side, and a first through-hole 130 is also provided through the annular baffle 120. The annular housing 110 is sleeved over and connected to the annular baffle 120. The cross-section of the annular housing 110 can be a common structure, such as an ellipse, circle, or polygon, as long as it has a through-hole in the middle and can be sleeved over the annular baffle 120. The annular housing 110 is provided with a first cavity 111, which communicates with the first passage 160 via the first through-hole 130. The floating plate 140 is located in the first cavity 111 and separates a first noise reduction cavity 1111 from other parts of the first cavity 111. That is, the floating plate 140 isolates a part of the first cavity 111 to form the first noise reduction cavity 1111. The first through hole 130 connects the first noise reduction cavity 1111 and the first channel 160. At the same time, the floating plate 140 can be controlled by the adjustment component 150 to move in the first cavity 111 to change the volume of the first noise reduction cavity 1111.

[0069] The first cavity 111 may be a cavity with an opening on the side adjacent to the annular baffle 120. In this case, the annular baffle 120 blocks the open side of the first cavity 111. The first cavity 111 may also be a fully enclosed cavity, with only a hole corresponding to the first through hole 130 formed on the side adjacent to the annular baffle 120, and communicating with the first through hole 130 through the hole.

[0070] The floating plate 140 is arranged in the first cavity 111 in the following two ways, but not limited to:

[0071] For example, the annular housing 110 and the annular baffle 120 are arranged along Figure 2 The first cavity 111 is configured as a rectangular cavity. The floating plate 140 also extends along the X direction and is adapted to the shape of the first cavity 111. Driven by the adjusting component 150, the floating plate 140 can move toward or away from the annular baffle 120, that is, along the Y direction. At this time, the first through hole 130 can be set at any position of the annular baffle 120, as long as one end can be connected to the first cavity 111 and the other end can be connected to the first air duct.

[0072] Exemplarily, the floating plate 140 is arranged along Figure 2 The first through hole 130 extends in the Y direction and is adapted to the shape of the first cavity 111. For example, the first cavity 111 is configured as a ring, and the floating plate 140 is also configured as a ring plate. The floating plate 140 can be moved along the X direction under the drive of the adjustment component 150 to change the volume of the first noise reduction cavity 1111. At this time, the first through hole 130 can be arranged as much as possible toward 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 a wider frequency band of sound wave noise reduction.

[0073] Of course, the first floating plate 140 can also be set at other angles with the X or Y direction, as long as it can form an independent first noise reduction cavity 1111 connected to the first through hole 130 at the partition in the first cavity 111. This embodiment is not limited thereto.

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

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

[0076] Resonant sound absorption frequency of noise reduction components It 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 chamber 1111. By moving the floating plate 140, according to the above formula, the volume of the first noise reduction chamber 1111 decreases, and its resonant frequency increases. The adjustable range of sound waves adapted by the noise reduction assembly 100 is related to the adjustable volume of the first noise reduction chamber 1111.

[0079] According to the acoustic-electrical 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 for:

[0080]

[0081] Where, 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 in the annular baffle 120 after considering the thermoviscous effect; 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 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 modified length of the annular baffle 120 .

[0082] Impedance of the first noise reduction cavity 1111 for:

[0083]

[0084] Where, is the volume of the first noise reduction chamber 1111; is the equivalent mass density of the air in the first noise reduction cavity 1111 after considering the thermal viscosity effect; is the equivalent sound speed in the first noise reduction cavity 1111; is the equivalent wave number in the first noise reduction cavity 1111; and are respectively the thermal field function and the viscous field function in the first noise reduction cavity 1111; is the diameter of the equivalent circle of the rectangular cross section in the first noise reduction cavity 1111; and are the viscous wave number and thermal wave number in the first noise reduction cavity 1111 respectively.

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

[0086]

[0087] Then the transfer equation is:

[0088]

[0089] Among them, where: The acoustic transfer matrix (T) is the acoustic transfer matrix of the noise reduction component. It decomposes a complex piping system into several units and uses four matrix parameters ( ) is used to describe the corresponding relationship between the sound pressure p and 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 the four-terminal network in series and parallel. Finally, the acoustic characteristics of the entire system are discussed based on the total transfer matrix, where , , , .

[0090] Then, the transmittance is:

[0091]

[0092] Then the transmission loss is:

[0093]

[0094] It can be seen that during use, the position of the floating plate 140 can be adjusted by adjusting the component 150 according to the frequency of the sound wave to be reduced, so that the volume of the first noise reduction chamber 1111 changes to a point where the natural resonance frequency of the noise reduction component 100 is close to the frequency to be reduced. At this time, after the sound wave enters the first channel 160, it will enter the first noise reduction chamber 1111 through the first through hole 130, and cause the air column in the first through hole 130 to vibrate, thereby causing the gas in the first noise reduction chamber 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, thereby consuming the energy of the sound wave and effectively reducing the noise. This allows the noise reduction component 100 to be adaptively adjusted according to different noises during actual use, broadens the adaptability of the noise reduction component 100, and enables it to adapt to more complex noise environments.

[0095] In addition, compared with traditional acoustic metamaterials, the noise reduction component 100 is more convenient to process. The movement of the floating plate 140 can eliminate errors such as processing errors and theoretical model errors, which can effectively reduce processing costs.

[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 reduced. For example, if the frequency to be reduced is 152Hz, then it can be designed to target a minimum 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] Traditional acoustic metamaterials, if they are to target 152Hz sound waves, can only be processed according to 152Hz. Once the error is slightly large, it will cause the sound insulation peak to shift, and it will no longer be able to effectively reduce the noise of 152Hz sound waves.

[0098] In addition, during the actual processing, 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 along the X direction in the first cavity 111, that is, the moving direction of the floating plate 140 is the same as the extension direction of the annular baffle 120. In this way, 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 assembly 100, the following tests were conducted on the noise reduction effect of the noise reduction assembly 100 when the floating plate 140 was 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 housing 110 used in the test is annular in shape, and the first cavity 111, the annular baffle 120, and the floating plate 140 are also annular in shape. The inner diameter of the annular baffle 120 is 1150 mm, the outer diameter of the annular housing 110 is 1452 mm, the height of the annular housing 110 (length in the X direction) is 202 mm, the wall thickness of the annular baffle 120 and the annular housing 110 is 1.5 mm, and the thickness of the annular baffle 120 is 1.5 mm. The first through hole 130 is a circular hole with an inner diameter of 80 mm and a depth of 10 mm.

[0102] For vehicle exhaust pipes, transmission loss is only related to the structure and is not affected by the source impedance or the tailpipe's radiation characteristics. It is the most commonly used evaluation metric for muffler acoustic performance. When the inlet and outlet of the pipe where the noise reduction assembly 100 is placed meet the plane wave condition, the transmission loss can be expressed as:

[0103]

[0104] in, is the incident sound pressure at the structure inlet, is the ejected sound pressure at the structure outlet, is the area at the structure entrance, is the area at the structure outlet.

[0105] The acoustic performance simulation experiment was conducted using the pressure acoustics module of the multi-physics simulation software COMSOL Multiphysics®. First, a straight pipe was constructed to place the noise reduction component 100. A pressure boundary condition was applied at one end of the straight pipe. Figure 1 The noise spectrum of the exhaust pipe controls the input noise frequency. Because the air within the first through hole 130 experiences intense vibrations, heat loss must be considered. Therefore, "Narrow Area Acoustics" is set for the corresponding area (this module accounts for heat loss, the process of converting acoustic energy into thermal energy). Frequency domain analysis is performed to obtain the inlet and outlet areas and corresponding pressures of the straight pipe. The transmission loss of the noise reduction assembly 100 at different frequencies can be calculated using the above formula.

[0106] In the simulation experiment, the floating plate 140 is moved by 0.01m, 0.02m, 0.03m and 0.04m in sequence, so that the volume of the first noise reduction cavity 1111 is reduced in sequence. The specific results of the simulation experiment are as follows: Figure 13 As shown, Figure 13 The vertical axis TL is the transmission loss.

[0107] from Figure 13 It can be seen from the figure that after the floating plate 140 is moved, the smaller the volume of the first noise reduction cavity 1111 is, the larger the corresponding noise frequency is, and each different position can achieve a better noise reduction effect on noise of a specific frequency.

[0108] When used alone, each noise reduction component 100 can process noises of different frequencies. If you want to process multiple noises of different frequencies, you can use multiple noise reduction components 100 in series. That is, when using the noise reduction components 100, at least two can be set 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 following experiment measures the transmission loss when two noise reduction components 100 are used in series. During the measurement, the position of the floating baffle is adjusted so that the two noise reduction components 100 correspond to two noises of different frequencies. The measurement results are shown in FIG. Figure 14 As shown, Figure 14 The vertical axis TL in FIG. 1 is the transmission loss. It can be seen from the figure that when two noise reduction components 100 are used in series, the noise reduction effect of a single noise reduction component 100 is not affected.

[0110] In some embodiments, the noise reduction assembly 100 further includes a microphone located at the outlet end of the first channel 160 , and the microphone 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 indicator to measure the intensity of sound waves, usually expressed in decibels (dB). A microphone, also known as a microphone, can convert sound waves into electrical signals. During the use of the noise reduction component 100, the diaphragm of the microphone receives sound waves, causing it to vibrate. 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 condenser microphone is capacitance change, and the conversion mechanism of an electromagnetic microphone is electromagnetic induction. The specific selection can be made according to actual conditions, and this embodiment does not limit it here. The converted electrical signal is amplified and processed, for example, after filtering and calibration, 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 the sound waves at the outlet of the first channel 160. At this time, the position of the floating plate 140 can be adjusted through the adjustment component 150 according to the real-time sound pressure level to change the volume of the first noise reduction chamber 1111. When the real-time sound pressure level decreases and the derivative of the decrease value is zero, the position of the floating plate 140 is optimal, and noise reduction can be effectively performed.

[0113] The adjustment component 150 includes but is not limited to the following two structures:

[0114] Exemplarily, the adjusting component 150 includes a driving motor, an 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.

[0115] The driving motor can be a linear motor, whose output end is directly connected to one side of the floating plate 140, driving the floating plate 140 to move in the corresponding direction. At this time, the driving motor can be fixed on the annular shell 110 or on the frame of the structure using the noise reduction component 100, as long as the driving motor does 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 along the extension direction of the screw rod in the first cavity 111, 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 thus 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. By screwing the two positioning blocks 152, the positioning blocks 152 can be moved along the length direction of the screw 151 to move the floating plate 140 along the extension direction of the screw 151, thereby adjusting the position of the floating plate 140 in the first cavity 111.

[0120] It should be noted that the extending direction of the screw 151 coincides with the moving trajectory of the floating plate 140 . For example, when the floating plate 140 is an annular plate, the screw 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, an annular protrusion 131 is provided on at least one side of the annular baffle 120, and the annular protrusion 131 extends into the first cavity 111 or the first channel 160. A second through hole is provided on the annular protrusion 131 and passes through the annular protrusion 131. The second through hole is connected to the first through hole 130.

[0123] For example, 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 connected to the first through hole 130. This method 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 the through hole, the lower the frequency of the sound wave that can be targeted. This setting method can reduce the lower limit of the frequency of the sound wave that the noise reduction component 100 can target without increasing the volume of the first cavity 111, that is, it can maximize the ability of the noise reduction component 100 to handle low-frequency noise without increasing its volume.

[0124] It should be noted that the annular protrusion 131 can also be set only on one side of the annular baffle 120. When it is set only on one side, it can be selected to be set on the side adjacent to the annular baffle 120 and the first cavity 111. Even if the annular protrusion 131 extends into the first cavity 111, this will not affect the flow of the medium transmitting sound waves in the first channel 160, thereby avoiding the introduction of 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 shell 110, that is, the length of the annular baffle 120 is greater than the length of the annular shell 110. In this way, when the noise reduction component 100 is used in equipment such as a muffler, it can be directly assembled with other components through the mounting portion 170 to reduce the difficulty of installation.

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

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

[0128] Specifically, the inlet end of the conductive member 200 is connected to the component that generates noise. The conductive member 200 is mainly used to guide the sound waves into the first channel 160 of the noise reduction component 100 to reduce noise 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 target noises of 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, which is not limited in this embodiment.

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

[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 placed at different positions in the first cavity 111, so that the two noise reduction components 100 can target noise in different frequency bands.

[0133] Secondly, the structures of the two noise reduction components 100 are different, so that the volume adjustment ranges of the first noise reduction cavities 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 300Hz-1000Hz turbulent noise generated by the interaction between gas and solid and the airflow itself ( Figure 12 The area in the middle right box) is more complex in composition, and it is difficult to perform noise reduction using only the noise reduction component 100.

[0135] In this regard, the muffler may further include a sound absorbing component 300, which is located between the noise reduction component 100 and the conductive component 200, or the sound absorbing component 300 is 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 absorbing assembly 300 includes a housing 310 and a first sound absorbing member 330. A third channel 320 is disposed within the housing 310, communicating with the first channel 160. The housing 310 can be configured in the shape of a polygonal prism, a cylinder, an elliptical column, or any other shape, as long as the third channel 320 is disposed therein.

[0137] The first sound absorbing component 330 is located in the third channel 320 and is provided with a plurality of second noise reduction cavities 336 , each of which has at least two different volumes. The first sound absorbing component 330 is also provided with a plurality of third through holes 333 , and each second noise reduction cavity 336 is connected to the third channel 320 via at least one third through hole 333 .

[0138] Exemplarily, the first sound-absorbing component 330 is located at the end of the noise reduction component 100 facing away from the conductive component 200, and the outlet end of the first channel 160 of the noise reduction component 100 adjacent to the shell 310 is connected to the third channel 320. The first sound-absorbing component 330 processes the noise processed by the noise reduction component 100. The first sound-absorbing component 330 can also be located between the noise reduction component 100 and the conductive component 200. The inlet end of the third channel 320 is connected to 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 shell 310 is connected to the outlet end of the third channel 320. The first sound-absorbing component 330 first processes the noise in a specific frequency band, and then the noise reduction component 100 performs subsequent processing on the noise in the remaining frequency bands.

[0139] The first sound-absorbing component 330 may include a main body component, and a plurality of second noise reduction cavities 336 are provided on at least one side of the main body component. The second noise reduction cavities 336 may 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 hole 333, the second noise reduction cavities 336 of different volumes can resonate with respect to the sound waves of different frequency bands, thereby reducing the noise energy of the corresponding frequency bands, so that the noise of multiple different frequency bands can be processed by the first sound-absorbing component 330, thereby 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 be annular with a larger volume, which can be used to process noise in a lower frequency band, while the first sound-absorbing component 330 can be set to have a second noise reduction cavity 336 with a relatively smaller volume to process noise in a slightly higher frequency band, thereby reducing the volume of the silencer and processing noise in different frequency bands.

[0141] It should be noted that if only the first sound-absorbing component 330 is provided, then for the noise in the ultra-low frequency band, the volume of the second noise reduction chamber 336 is required to be larger, which will result in a larger volume of the first sound-absorbing component 330, thereby significantly increasing the volume of the muffler, which will limit the scenarios in which the muffler can be used. Therefore, the noise reduction assembly 100 and the first sound-absorbing component 330 are used in combination, each targeting different noises, which can effectively reduce the overall volume of the muffler and help reduce costs.

[0142] Further, see Figure 9 、 Figure 10 and Figure 11 As shown, the volume of the second noise reduction cavity 336 decreases or increases in sequence along the direction of movement of the sound wave in the third channel 320, for example, along Figure 9 The direction of the arrows increases in sequence.

[0143] Specifically, when the effective area of ​​the third through hole 333 for the fluid to pass through remains unchanged, the larger the volume of the second noise reduction cavity 336 is, the lower the frequency of the corresponding sound wave is. Figure 11 The second noise reduction cavity 336 and Figure 9 The arrangement of the second noise reduction cavity 336 is the same as Figure 9 As indicated by the middle arrow, 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 direction of movement of the sound wave, so that the sound waves of different frequencies can be processed successively.

[0144] In practical applications, the third channel 320 generally has a certain volume. In order to make full use of this space, multiple first sound absorbing components 330 can be arranged in sequence and spaced apart in a direction perpendicular to the extension direction of the third channel 320, that is, the first sound absorbing components 330 are stacked in sequence along the radial direction of the third channel 320.

[0145] Of course, the length direction of the first sound absorbing component 330 is consistent with the extension direction of the third channel 320, which can further save space and arrange more first sound absorbing components 330 in the smallest possible space to improve the sound absorption effect.

[0146] In some embodiments, the first sound-absorbing component 330 includes a main body and two cover plates 332. Multiple cavities are provided on opposite sides of the main body. The two cover plates 332 are respectively provided on either side of the main body, enclosing the cavities to form a second noise reduction cavity 336. Third through holes 333 are provided on the cover plates 332 and extend through the thickness of the cover plates 332.

[0147] Specifically, the length direction of the main body component is the same as the extension direction of the third channel 320. When 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 the 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 is 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 component 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. The two grid support plates 334 are disposed 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. The cover plate 332 is disposed on the side of the grid support plate 334 facing 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 processing difficulty of 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, reduce the occupied space, and also help 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. Since 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 to change exponentially 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] Where, is the impedance of the third through hole 333 of the nth first sound absorbing component 330, is the impedance of the second noise reduction cavity 336 of the nth first sound absorbing component 330. For details on its parameters, see the calculation method for the impedance of the first noise reduction cavity 1111 and the impedance of the first through hole 130 in the noise reduction assembly 100 in the above embodiment. Then, the transfer equation is:

[0155]

[0156] in: .

[0157] Then the transmittance of the plurality of first sound absorbing components 330 is:

[0158]

[0159] Then the transmission loss of the plurality of first sound absorbing components 330 is:

[0160]

[0161] The transfer equation used in combination with the plurality of first sound absorbing components 330 and the noise reduction assembly 100 is:

[0162]

[0163] in: is the acoustic transfer matrix of the noise reduction assembly 100, is the acoustic transfer matrix of the first sound absorbing member 330 .

[0164] The transmittance when the plurality of first sound absorbing components 330 and the noise reduction assembly 100 are used in combination is:

[0165]

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

[0167]

[0168] For ease of understanding, the structure of the first sound absorbing component 330 is further described below with some examples:

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

[0170] For example, the sizes of the through slots 335 on the same grid support plate 334 are different, the sizes of the through slots 335 of the two grid support plates 334 are also different, and the inner diameters of the third through holes 333 on the same cover plate 332 are different, which can increase the frequency band of noise that can be processed by the first sound-absorbing component 330, but 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 size of the through groove 335 on the grid support plate 334 and the inner diameter of the third through hole 333 on the cover plate 332 can be adjusted according to a certain rule, or only one can be changed while the other remains unchanged, or both can be changed randomly. This embodiment does not limit them here.

[0172] In addition, in actual production, the shape of the third channel 320 may not be rectangular, but may be a circular or elliptical structure. Taking the circular shape as an example, in this case, the inner diameter of the third channel 320 decreases from the middle toward the two sides, and the size of the corresponding first sound-absorbing component 330 will also decrease successively. At this time, in the width direction of the first sound-absorbing component 330, the number of through grooves 335 can be increased on the grid support plate 334 corresponding to the larger first sound-absorbing component 330, while the number of through grooves 335 can be reduced on the smaller grid support plate 334.

[0173] In some embodiments, the sound absorbing assembly 300 further includes a second sound absorbing member 340 located within the third channel 320. The second sound absorbing member 340 is located at an inlet end or an outlet end of the first sound absorbing member 330. The frequency corresponding to the noise in the sound waves processed by the second sound absorbing member 340 is greater than the frequency corresponding to the noise in the sound waves processed by the first sound absorbing member 330.

[0174] When the first sound-absorbing component 330, the second sound-absorbing component 340 and the noise reduction component 100 are used in conjunction, the volume of the first noise reduction chamber 1111 of the noise reduction component 100 is adjustable, which can be used to process special single-frequency noise, such as the noise peaks generated by different rotational speeds when the fan is running. The first sound-absorbing component 330 and the second sound-absorbing component 340 can work together to process the gas-solid interaction noise and the turbulent noise of the airflow itself, thereby adapting to the processing of common wide-band and narrow-band mixed noise.

[0175] Furthermore, the second sound absorbing component 340 includes a plurality of sound insulation cotton sheets sequentially arranged at intervals along an extending direction perpendicular to 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 absorbing components 330, and the gaps between adjacent sound insulation cotton sheets correspond to the gaps between adjacent first sound absorbing components 330, so that sound waves can effectively move between the two.

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

[0178] The test used ten first sound absorbing components 330 and ten sound insulation cotton sheets, both of which were stacked in sequence along the radial direction of the third channel 320, and the gap between two adjacent first sound absorbing components 330 was the same as and opposite to the gap between two adjacent sound insulation cotton sheets.

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

[0180] The size of the first sound absorbing member 330 is 727.1 mm 50mm The width of the second noise reduction chamber 336 is 23.5 mm, with the 727.1 mm side parallel to the noise transmission direction. The gap between adjacent sound insulation sheets is 175 mm. The thickness of the middle partition 331 and cover plate 332 is 1 mm, and the thickness of the grid support plate 334 is 23.5 mm.

[0181] The second noise reduction cavities 336 are rectangular cavities. For the same first sound absorbing component 330, on one side of the middle partition 331, corresponding to the side with a length of 727.1 mm, there are 15 rows of second noise reduction cavities 336, and on the side with a length of 1674 mm, there are 27 rows of second noise reduction cavities 336 (the multiple second noise reduction cavities 336 in each row have different sizes). In other words, each first sound absorbing component 330 is provided with a total of 810 second noise reduction cavities 336. In a direction parallel to the direction of noise transmission, the multiple second noise reduction cavities 336 are arranged in order from 1 to 15, and their lengths and widths vary according to Table 1:

[0182] Table 1

[0183]

[0184] Among them, the length is the length of one side of the second noise reduction cavity 336 extending along the noise transmission direction, the third through holes 333 on the two cover plates 332 are both circular 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, and each second noise reduction cavity 336 corresponds to a third through hole 333.

[0185] The acoustic performance simulation experiment was conducted using the pressure acoustics module of COMSOL Multiphysics® software. First, a straight pipe was constructed, and then a first sound absorbing component 330 and / or a sound insulation sheet was constructed in the straight pipe according to the test requirements. A pressure boundary condition was applied at one end of the straight pipe, and the pressure was adjusted according to the pressure. Figure 1 The noise spectrum of the exhaust pipe controls the input noise frequency. Due to the intense air vibration within the third through hole 333, heat loss needs to be considered. Therefore, "Narrow Area Acoustics" is set for the corresponding area (this module accounts for heat loss, the process of converting sound energy into heat). The sound insulation area is set to Porous Medium Acoustics, using nine parameters to describe the heat loss in the area. Frequency domain analysis is performed to obtain the inlet and outlet areas and corresponding pressures of the straight pipe. The transmission loss at different frequencies can then be calculated using the transmission loss formula used in the noise reduction component 100 simulation experiment.

[0186] The simulation test results are as follows Figure 15 As shown, from Figure 15It can be seen that when ten first sound-absorbing components 330 are used alone, only low-frequency noise within the range of 500-1000 Hz can be processed, and when ten sound-insulating cotton sheets are used alone, only high-frequency noise can be processed. However, when the first sound-absorbing components 330 and the second sound-absorbing components 340 are used in combination, a good processing effect can be achieved for noise within both frequency ranges. It can also be seen that the second sound-absorbing components 340 improve the effective area of ​​the first sound-absorbing components 330 by more than 2 dB, but do not affect the effective frequency position of the first sound-absorbing components 330. Therefore, when the first sound-absorbing components 330 process low-frequency noise, there is no need to consider the impact of the second sound-absorbing components 340.

[0187] In order to determine the effect 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 tested separately.

[0188] The structures of the first sound absorbing component 330 used in Example 1 and the first sound absorbing component 330 used in Example 2 are the same, and both are the first sound absorbing component 330 in the above-mentioned simulation test. The only difference is that the volume of the second noise reduction cavity 336 in Example 1 decreases along the direction of movement 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 along the direction of movement of the sound wave. The simulation test results are as follows: Figure 16 As shown, from Figure 16 It can be seen from the figure that the setting direction of the second noise reduction cavity 336 does not have a significant impact on the transmission loss.

[0189] In actual applications, the positions of the first sound absorbing member 330, the second sound absorbing member 340, and the noise reduction assembly 100 can be adjusted according to actual conditions. However, whether the first sound absorbing member 330 is adjacent to the noise reduction assembly 100 or the second sound absorbing member 340 is adjacent to the noise reduction assembly 100, it is preferable to maintain a certain gap with the outlet end of the second channel of the noise reduction assembly 100 to facilitate sound waves to enter the third channel 320.

[0190] For example, see Figure 4 and Figure 5 As shown, the noise reduction component 100 is connected to the conductive component 200, and 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 waves passes through the noise reduction component 100, the second sound absorbing component 340 and the first sound absorbing component 330 in sequence, and finally leaves the muffler from the outlet end of the third channel 320.

[0191] For example, Figure 11 As shown, the noise reduction assembly 100 is connected to the conductive member 200 , and the first sound absorbing component 330 is located between the noise reduction assembly 100 and the second sound absorbing component 340 .

[0192] For example, Figure 7 As shown, two or more noise reduction components 100 are arranged in sequence, and their first channels 160 are connected in series. The noise reduction component 100 adjacent to the conductive member 200 is connected to the conductive member 200, and the outlet end of the first channel 160 of the noise reduction component 100 facing away from the conductive member 200 is connected to the third channel 320, and the first sound absorbing component 330 is located between the second sound absorbing component 340 and the noise reduction component 100 facing away from the conductive member 200.

[0193] For example, Figure 6 As shown, the inlet end of the third channel 320 of the shell 310 is connected to the outlet end of the second channel of the conductive member 200, the noise reduction component 100 is connected to the end of the shell 310 facing away from the conductive member 200, the second sound absorbing component 340 is adjacent to the conductive member 200, and the first sound absorbing component 330 is located between the second sound absorbing component 340 and the noise reduction component 100.

[0194] An embodiment of the present application further provides a vehicle, comprising a vehicle body and the muffler in the above embodiment, wherein the muffler is mounted on the vehicle body.

[0195] Exemplarily, the conductive 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 conductive member 200 is connected to the end of the exhaust pipe. The muffler can adaptively process the noise of the fan rotation to improve the noise reduction effect.

[0196] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A muffler, characterized in that: The invention comprises a conductive member and a noise reduction component (100), wherein the noise reduction component (100) comprises: an annular baffle (120), wherein a first channel (160) is formed inside the annular baffle (120), and a first through hole (130) is provided on the annular baffle (120) and penetrates 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 in 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), the adjusting component (150) being used to adjust the position of the floating plate (140) in the first cavity (111) to adjust the volume of the first noise reduction cavity (1111); The conductive member (200) is provided with a second channel, and the inlet end of the first channel (160) is connected to the outlet end of the second channel; The muffler further comprises a sound absorbing component (300), the sound absorbing component (300) being located between the noise reduction component (100) and the conductive member (200), or the sound absorbing component (300) being located on a side of the noise reduction component (100) away from the conductive member (200), and the frequency corresponding to the noise in the sound waves processed by the sound absorbing component (300) being greater than the frequency corresponding to the noise in the sound waves processed by the noise reduction component (100); the sound absorbing component (300) comprising: a housing (310), wherein a third channel (320) is provided 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) is located in the third channel (320), and a plurality of second noise reduction cavities (336) are provided on the first sound absorbing component (330); a plurality of third through holes (333) are also provided on the first sound absorbing component (330), and each of the second noise reduction cavities (336) is connected to the third channel (320) through at least one of the third through holes (333); the first sound absorbing component (330) comprises: a main body component, wherein the main body component is provided with a plurality of cavities on both sides of the opposite sides in the extension direction of the third channel (320); Two cover plates (332), the two cover plates (332) are respectively provided on both sides of the main body component and close the cavity to form the second noise reduction cavity (336), the third through hole (333) is provided on the cover plate (332) and penetrates the cover plate (332) along the thickness direction of the cover plate (332); The length direction of the first sound absorbing component (330) is the same as the extension direction of the third channel (320), and a plurality of first sound absorbing components (330) are sequentially arranged at intervals along the radial direction of the third channel (320), with gaps between adjacent first sound absorbing components (330).

2. The muffler 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 muffler 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 muffler according to claim 3, characterized in that The adjusting component (150) includes a driving motor, an 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 muffler according to claim 1, characterized in that The adjusting component (150) includes a screw (151) provided on the annular housing (110), the screw (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 (151) are provided on the screw (151), and the two positioning blocks (152) are respectively provided 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 (151).

6. The muffler according to claim 1, characterized in that An annular protrusion (131) is provided on at least one of the two sides of the annular baffle (120) in the extension direction. The annular protrusion (131) extends into the first cavity (111) or the first channel (160). A second through hole is provided on the annular protrusion (131) and passes through the annular protrusion (131). The second through hole is communicated with the first through hole (130).

7. The muffler according to claim 1, 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. The muffler according to claim 1, wherein: At least two noise reduction components (100) are provided along the moving direction of the sound wave, and the first channels (160) of at least two noise reduction components (100) are connected to each other.

9. The muffler according to claim 1, characterized in that At least one of the plurality of second noise reduction chambers (336) has a volume different from that of the remaining chambers.

10. The muffler according to claim 9, characterized in that The volumes of the plurality of second noise reduction cavities (336) decrease or increase in sequence along the moving direction of the sound wave in the third channel (320).

11. The muffler according to claim 1, characterized in that The main body component includes: Middle partition (331); Two grid support plates (334), each provided with a plurality of through slots (335), the two grid support plates (334) being disposed on opposite sides of the middle partition plate (331), so as to form the cavity by closing one end of the through slots (335) through the middle partition plate (331); Wherein, the cover plate (332) is provided on a side of the grid support plate (334) facing away from the middle partition plate (331).

12. The muffler according to claim 11, characterized in that The two grid support plates (334) have the same structure, and of the two cover plates (332), the effective area of ​​the third through hole (333) on one is larger than the effective area of ​​the third through hole (333) on the other.

13. The muffler according to any one of claims 1 to 12, characterized in that: The sound absorbing assembly (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 the frequency corresponding to the noise in the sound waves processed by the second sound absorbing component (340) being greater than the frequency corresponding to the noise in the sound waves processed by the first sound absorbing component (330).

14. The muffler according to claim 13, characterized in that The second sound absorbing component (340) includes a plurality of sound insulation cotton sheets sequentially spaced apart along the radial direction of the third channel (320).

15. A vehicle, characterized in that: The utility model comprises a vehicle body and the muffler according to any one of claims 1 to 14, wherein the muffler is mounted on the vehicle body.

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