CN214377656U - Sound absorber unit and vehicle wheel with sound absorber - Google Patents

Abstract

The present application relates to a sound absorber unit and a vehicle wheel having a sound absorber comprising at least one sound absorber unit or at least one sound absorber module integrated from a plurality of sound absorber units. The sound absorber unit is constructed into a box body in a hexahedron shape, a three-layer Helmholtz resonance sound absorption structure with double holes and single holes combined is formed, and meanwhile, the sound absorber unit or the sound absorber assembly forms a structural resonance sound absorber. According to the application, the double-absorption wheel air chamber sound resonance function organically combining the Helmholtz resonance sound absorption and the structural resonance sound absorption can be realized.

Description

Sound absorber unit and vehicle wheel with sound absorber

Technical Field

The utility model relates to a sound absorber unit and a wheel with sound absorber, especially be furnished with pneumatic tire's auto wheel.

Background

In the normal running process of the vehicle, the excitation of the road surface to the wheels and the excitation of the wheel axle to the wheels caused by the rotation unbalance of the wheels can excite an air chamber in the wheels to generate acoustic resonance, and the resonance is transmitted to a vehicle body structure through the wheel axle and a suspension system and then radiates noise in the vehicle. The noise characteristics of the car noise suppression device are mainly low-frequency narrow bands, the magnitude is high, noise interference is formed for the interior passenger environment of the car, and effective control is needed.

Currently, there are numerous studies and patents that provide methods to effectively control such acoustic resonances. The method mainly adopts a sound absorption control principle, wherein the Helmholtz resonance sound absorption is widely applied and has a good effect. For example, chinese patents CN101301842B, CN104981359B, CN105209267B, and CN104908513B relate to a series of wheel solutions implemented based on helmholtz resonator noise reduction method. However, in the solutions known from the prior art, the constructive design and mounting structure of the helmholtz resonator is complex and also not ideal in terms of its sound absorption effect. In practice, even if the wheels are of the same type, the acoustic resonance frequency is different due to different driving states and different product positioning, and high-magnitude noise of a plurality of narrow bands is also frequently generated. In particular, since the conditions during four-wheel driving are different, there are a plurality of narrow-band high-value noises with different distribution characteristics, so that the noises present a larger noise value in a wider frequency band, which is contrary to the advantages of helmholtz narrow-band sound absorption. Therefore, the structure based on the helmholtz sound absorption principle still needs to be continuously developed and improved. Meanwhile, the structure based on the principle is various, and a space for further improvement is provided in the aspects of amplitude and bandwidth control. In addition, the helmholtz sound absorption principle is also suitable to be combined with other noise reduction principles (such as box-type structure resonance sound absorption) to make up for the deficiency of the helmholtz principle, so that the efficiency of controlling the resonance of the air chamber can be effectively improved, but the integration of various noise reduction principles at present is not popularized and applied in the aspect of reducing the acoustic resonance of the wheel air chamber.

Further, in the case of the above-described prior art, the structural design and mounting structure of the helmholtz resonator are complicated, and for this reason, the resonator member ("sub-air chamber member") is structured with a flange-like thin plate flange ("rim portion"), a groove ("groove portion") is formed in a wall surface specially structured in the boss, and the resonator member is fixed and positioned by the flange-like thin plate flange and the groove portion of the wall surface, and this engagement mechanism is difficult to secure the connection strength due to its thin-walled feature, and on the other hand, since the connection and fitting of both the members are basically dependent on the structural dimensional accuracy, it is highly required for the processing and manufacturing of the members, and moreover, the alignment and mounting work of both the members is troublesome, and the final mounting and fastening force cannot be controlled.

SUMMERY OF THE UTILITY MODEL

The utility model discloses plan to provide a sound absorber unit based on helmholtz resonator principle is constructed very much, is applied to the wheel with the sound absorbing device that it constitutes and falls and make an uproar to partly or overcome the above-mentioned defect that exists among the prior art completely, especially, through the mode that adopts porous three-layer helmholtz structure sound absorption and box structure resonance sound absorption to combine together, realize more effectual noise reduction.

In order to promote the wheel air chamber resonance control effect, the utility model discloses mainly based on following thought: firstly, a porous three-layer resonance sound absorption structure is adopted, and the defect that the single Helmholtz resonance sound absorption is difficult to realize effective control of low-frequency broadband noise under a limited volume is overcome in the control principle; secondly, a box-shaped structure in a hexahedron shape is adopted, preferably made of plastic materials, the structural resonance frequency of the box-shaped structure is designed to be consistent with the resonance frequency of the air chamber, resonance sound absorption is realized under the combined action of three layers of double holes and a single hole, and higher noise reduction is realized in a wider frequency band; thirdly, a three-layer hollow square tube structure is allowed to be adopted, the structure is simple, and the processing is convenient.

In particular, the present invention provides a sound absorber unit to be mounted on a moving part (for example, a hub of a wheel) in a gas environment for reducing acoustic resonance, characterized in that the sound absorber unit is constructed as a box body in a hexahedron shape and forms a three-layer helmholtz resonance sound absorbing structure in which a double hole and a single hole are combined, the box body has two sides defining boundaries at both ends of the box body in a moving direction of the moving part, wherein one end forms an open end side having an opening into a cavity inside the box body, and the other end forms a closed end side; the interior of the box body is divided into a first cavity, a second cavity and a third cavity which are sequentially arranged along the movement direction of the moving part through a first partition plate and a second partition plate; wherein two first hollow tube orifices are formed on the side surface of the open end, the orifice of the first hollow tube is opened to the gas environment space, and the first hollow tube extends into the first cavity by a distance corresponding to the tube length; a pipe orifice of a second hollow pipe is formed on the first partition plate, the pipe orifice of the second hollow pipe is opened to the first cavity, and the second hollow pipe extends into the second cavity by a distance corresponding to the pipe length of the second hollow pipe; two third hollow pipe orifices are formed on the second partition plate, the third hollow pipe orifices are opened to the second cavity, and the third hollow pipe extends into the third cavity by a distance corresponding to the pipe length of the third hollow pipe; the first cavity, the second cavity and the third cavity form three resonant cavities with layered functions of the three-layer Helmholtz resonance sound absorption structure.

It should be noted that the "hexahedron shape" in the present application is not strictly limited to a regular hexahedron (e.g., rectangular parallelepiped) shape in a geometric sense, but may generally have a shape similar to a hexahedron, wherein one or more faces are configured to have a certain curvature (e.g., the bottom surface and/or the top surface of the case body has a circular arc shape adapted to the outer surface profile of the rim, i.e., has a "curved hexahedron shape") and/or have a local convex or concave structure (e.g., for installation or fixation purposes), may not be absolutely orthogonal between intersecting faces, may not be absolutely parallel between opposing faces, and does not affect the implementation of the technical solution of the present invention.

The utility model discloses when promoting wheel air chamber resonance control effect, to the structural design in sound absorbing device, still should ensure to realize its contour machining through the production technology who is suitable for. According to one embodiment, the sound absorber unit is an arc-shaped hexahedral case integrally formed from a metal material or a plastic material. According to another embodiment, the sound absorber unit is an arc-shaped hexahedral box body made of metal plates or plastic plates through splicing and welding.

The first hollow pipe, the second hollow pipe and the third hollow pipe can be square pipes or round pipes. Particularly, the sound absorber unit with the three-layer hollow square tube structure can be conveniently processed and manufactured by using the conventional production technology.

According to one embodiment, it is advantageous that the structural parameters of the housing of the sound absorber unit, including the first and second partition plates, the plate body thicknesses of the open-end side and the closed-end side, the orifice diameters and the tube lengths of the first, second and third hollow tubes, the shapes, volumes and wall thicknesses of the first, second and third cavities, are determined by the predetermined sound absorption coefficient and sound absorption amount of the three-layer helmholtz resonance sound absorbing structure.

Accordingly, the present invention provides a wheel equipped with a sound absorber installed inside a wheel air chamber for reducing acoustic resonance, the sound absorber including at least one sound absorber unit as described above or at least one sound absorber assembly combined as a whole by a plurality of the sound absorber units.

According to one embodiment, the sound absorber unit or the sound absorber assembly can be fastened to the hub of the wheel by means of a fastening element. In particular, the use of a tensioning restraining element to secure the absorber unit allows to carry out an easy and controlled mounting operation, while ensuring easy disassembly of the wheel assembly (and in particular of the absorber module thereof), which is beneficial for subsequent maintenance and replacement of spare parts.

The sound absorber unit or the sound absorber assembly may be integrally formed of a metal material or a plastic material. Advantageously, the box-shaped sound absorber unit or sound absorber assembly itself forms a structural resonance sound absorber, as which the first-order natural mode frequency coincides with the first-order natural mode frequency of the wheel air chamber.

According to one embodiment, the restraining element is a strap (for example a steel band) which is pressed from the top side of the casing of the sound absorber unit or sound absorber module against the outer surface of the rim of the wheel hub and fastens the sound absorber unit or sound absorber module around the wheel hub, the two ends of the strap being fixedly connected by a snap connection, the strap tension being adjustable and/or displayable by means of a fastening tool.

In this connection, it is advantageous if the sound absorber unit or the sound absorber module is provided on its box top face with a U-shaped recess for the insertion of the strap.

According to one embodiment, the sound absorber assembly is formed by combining two sound absorber units which are connected directly or through a thin plate at the side of the closed end. By adopting the sound absorber component, the situation that the sound absorbing structure is installed inversely in the way of meeting the flow caused by misorientation is not needed to be worried about during installation, and in the actual use process, the wheels provided with the corresponding sound absorbing devices can be randomly exchanged without influencing the noise reduction effect.

According to one embodiment, a plurality of said sound absorber units or said sound absorber assemblies are arranged side by side on the hub of the wheel, or are arranged along the circumference of the hub in a distributed manner, so as to optimize or adapt to the sound absorption and noise reduction requirements of the wheel as a whole or the dynamic balance characteristics thereof. In particular, a plurality of sound absorber units or sound absorber assemblies can be arranged uniformly along the circumferential direction of the wheel hub, for example, two sound absorber units (or sound absorber assemblies) can be arranged symmetrically along the circumferential direction of the wheel hub, i.e., mounted opposite to each other in the wheel diameter direction, for the specific case of a specific vehicle type.

According to one embodiment, the sound absorber unit or the sound absorber assembly rests with the bottom side of the housing against the outer rim surface of the wheel hub in the mounted state. In this connection, it is expedient if the sound absorber unit or the sound absorber module is provided with at least one bend extending transversely along its housing, which bend divides the sound absorber unit or the sound absorber module in its housing longitudinal direction into at least two sections in order to adapt the housing base to the circular-arc-shaped contour of the outer surface of the rim in the mounted state. For the sound absorber unit, for example, the bent portion may be provided between the first and second chambers, the second and third chambers; for example, the bend can additionally be provided at the connection point of the sound absorber unit for the sound absorber module. The bending part can be designed as a material weak part of the box body, can be continuous or discontinuous along the transverse direction of the box body, can transversely extend through the box body, and can also only extend on a part of the transverse section of the box body.

The utility model discloses the beneficial technological effect that can realize lies in very much, has constituteed a comprehensive sound absorbing structure by the three-layer resonance sound absorption that diplopore and haplopore combined together and structure resonance sound absorption, can realize more effectual sound absorption effect, and this embodiment is in: firstly, the sound absorption frequency is closer to the low frequency; secondly, the sound absorption frequency band is wider; thirdly, the sound absorption capacity is higher.

Drawings

In which some exemplary embodiments of the invention are shown. The embodiments and figures disclosed herein are to be regarded as illustrative rather than restrictive. It is also noted that for purposes of clarity of illustration, certain features are not necessarily drawn to scale in the drawings.

Fig. 1 is a schematic view of the mounting of a sound absorber unit on a wheel.

Fig. 2 is a schematic view of a sound absorber unit according to a preferred embodiment arranged on a wheel hub.

Fig. 3 is a schematic view of the construction principle of the sound absorber unit.

Fig. 4 is a graph of noise reduction measured by simulating acoustic behavior of a wheel/tire in one example of an application.

Wherein: d-the side of the opening end of the box body, D ' -the side of the closed end of the box body, B-a thin plate, 1/1 ' -a first hollow tube, 2-a first cavity, 3-a first partition plate, 4-a second hollow tube, 5-a second cavity, 6-a second partition plate, 7/7 ' -a third hollow tube, 8-a third cavity and 9-a U-shaped groove; 10-sound absorber unit, 20-hub, 30-wheel air chamber, 40-tire, 50-binding element.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first," "second," "third," and the like in the description and claims of this application and in the accompanying drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprising" and "having," as well as any variant thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of steps or elements is not limited to those listed but may alternatively include other steps or elements not listed or inherent to such process, method, article, or apparatus. It will be understood by those skilled in the art that throughout the present specification and claims, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, as used herein, refer to an orientation or positional relationship as shown in the drawings, which are used for convenience in describing the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device, mechanism, structure, or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

Fig. 1 is a schematic view of the mounting of a sound absorber unit on a wheel.

The present application provides a sound absorber unit 10 mounted on a moving part (particularly the hub 20 of an automotive wheel equipped with a pneumatic tire 40 shown in fig. 1) in a gaseous environment (particularly the wheel air chamber 30 shown in fig. 1) to reduce acoustic resonance. As shown in fig. 2 and in particular in fig. 3, the sound absorber unit is configured as a box of hexahedral shape having two sides bounding the two ends of the box in the direction of movement of the moving part, one of the ends forming an open end side D, having an opening into the cavity inside the box, and the other end forming a closed end side D', and forms a three-layer helmholtz resonance sound absorbing structure combining double and single holes; the interior of the box body is divided into a first cavity 2, a second cavity 5 and a third cavity 8 which are arranged in sequence along the moving direction of the moving part through a first partition plate 3 and a second partition plate 6; wherein, two first hollow tubes 1, 1' are formed on the open end side D, the tube openings of the first hollow tubes opening into the gas environment space, the first hollow tubes extending into the first cavity 2 at a distance corresponding to their tube length; a second hollow tube 4, the orifice of which opens into the first cavity 2, is formed in the first partition 3, said second hollow tube extending into the second cavity 5 by a distance corresponding to the tube length thereof; two third hollow tubes 7, 7' are formed on the second partition 6, the tubes of which open into the second cavity 5, and which extend into the third cavity 8 at a distance corresponding to the tube length thereof; the first cavity 2, the second cavity 5 and the third cavity 8 form three resonant cavities with layered functions of the three-layer Helmholtz resonance sound absorption structure.

It is possible that the sound absorber unit 10 is an arc-shaped hexahedral case integrally formed of a metal material or a plastic material; or, the sound absorber unit 10 is an arc hexahedral box body made of metal plates or plastic plates by splicing and welding.

The first hollow tubes 1 and 1 ', the second hollow tube 4 and the third hollow tubes 7 and 7' may be configured as square tubes or circular tubes.

According to the utility model discloses, the structural parameter of the box body of sound absorber unit 10 by predetermined sound absorption coefficient and the sound absorption volume of three-layer helmholtz resonance sound absorption structure are confirmed, structural parameter includes first baffle 3 and second baffle 6 open end side D and closed end side D ' the plate body thickness first hollow tube 1/1 ', second hollow tube 4 and third hollow tube 7/7 ' mouth of pipe aperture and pipe length first cavity 2, second cavity 5 and the shape, volume and the wall thickness of third cavity 8.

On this basis, the present application also provides a wheel equipped with sound-absorbing means for reducing acoustic resonance, installed inside the wheel air chamber 30, said sound-absorbing means comprising at least one sound absorber unit 10 as described above or at least one sound absorber assembly integrated by a plurality of said sound absorber units 10.

Fig. 2 is a schematic view of a sound absorber unit according to a preferred embodiment arranged on a wheel hub.

The sound absorber unit or the sound absorber assembly can be bound to the hub 20 of the wheel by means of a binding element 50 (see fig. 2).

Advantageously, the sound absorber unit 10 or the sound absorber assembly itself forms a structural resonance sound absorber, the first-order natural mode frequency of which corresponds to the first-order natural mode frequency of the wheel air chamber 30.

In this embodiment, the restraining element 50 is a strap (e.g. a steel band) which is pressed from the top side of the casing of the sound absorber unit 10 or sound absorber module against the outer surface of the rim of the wheel hub and fastens the sound absorber unit 10 or sound absorber module around the hub 20, the two ends of the strap being fixedly connected by snap-fastening, the tension of the strap being adjustable and/or displayable by means of a fastening tool. Suitably, the sound absorber unit 10 or the sound absorber module is provided with a U-shaped recess 9 (see fig. 3) on the top face of its case for insertion of the strap.

The sound absorber assembly may be assembled by connecting two sound absorber units 10 with their closed end sides D' directly or by connecting them through a thin plate B. In the embodiment shown in fig. 2, two sound absorber assemblies thus formed are arranged symmetrically in the circumferential direction of the wheel hub, i.e. mounted opposite one another in the wheel diameter direction.

According to actual needs, a plurality of the sound absorber units 10 or the sound absorber assemblies can be arranged on the hub 20 of the wheel side by side, or a plurality of the sound absorber units 10 or the sound absorber assemblies can be arranged along the circumferential direction of the hub in a distributed manner.

The sound absorber unit 10 or the sound absorber module rests with the bottom side of the housing against the outer rim surface of the hub 20 in the mounted state. For this purpose, the sound absorber unit 10 or the sound absorber module is expediently provided with at least one bend extending transversely along its housing, which divides the sound absorber unit or the sound absorber module in the longitudinal direction of its housing into at least two sections in order to adapt the housing base to the circular-arc contour of the outer surface of the rim in the installed state.

Fig. 3 shows a schematic view of the construction principle of the sound absorber unit.

Thus, according to this embodiment of the present invention, a three-layer sound absorbing structure mounted on the wheel hub 20 for reducing the acoustic resonance of the wheel air chamber can be realized by embodying a box-shaped structure (see fig. 2 and 3) having a circular hexahedron shape, which can be processed by an injection molding process, and in which three cavities (corresponding to 2, 5 and 8 indicated in the drawings) are divided by two thin plates (corresponding to 3 and 6 indicated in the drawings), one side (parallel to the first and second divided thin plates in the box) of the box is mounted (or constructed) with two first hollow square pipes (corresponding to 1 and 1 indicated in the drawings), and the divided thin plate between the first layer and the second layer in the box is mounted (or constructed) with one second hollow square pipe (corresponding to 4 indicated in the drawings), and the divided thin plate between the second layer and the third layer in the box is mounted (or constructed) with two third hollow square pipes (corresponding to 7 and 7' indicated in fig. 3) . The plane of the pipe orifice at one end of each of the two first hollow square pipes and the side surface of the box-type structure are on the same plane, and the pipe length extends into the first cavity 2; the plane of the pipe orifice at one end of the second hollow square pipe and the interior division thin plate are on the same plane, and the pipe length extends into the second cavity 5; the plane of the pipe orifice at one end of each of the two third hollow square pipes 3 and the inner partition thin plate are on the same plane, and the pipe length extends into the third cavity 8. Two first hollow square pipes communicate with each other with the tire air chamber, and box-type structure is whole to be installed on the circular arc global of wheel hub, forms the three-layer helmholtz resonance sound absorption structure that diplopore and haplopore combined together. This configuration is closer to low frequencies and wider in bandwidth than single cavity single hole helmholtz resonance sound absorption. Relevant parameters of the structural configuration are determined by using the sound absorption coefficient and the sound absorption quantity of the three-layer Helmholtz resonance sound absorption structure.

The box-type structure is preferably made of plastic materials with certain rigidity and strength in consideration of weight and cost, clings to the circular arc surface of the hub, and is fixedly installed by using a steel belt or other fasteners. In the sound absorption structure under the installation mode, the first-order natural modal frequency of the sound absorption structure is consistent with the first-order natural modal frequency of the wheel air chamber, and a structural resonance sound absorption device is formed by the sound absorption structure.

The natural mode/natural frequency of the structure meets the design requirements through material selection, thickness and shape adjustment, and can be calculated through a finite element method, particularly through software such as NASTRAN and ACTRAN. The sound absorption quantity of the porous three-layer resonance sound absorption structure can be increased through corresponding design, and the sound absorption bandwidth can also be increased.

The sound-absorbing box-like structure (or the sound-absorbing device or the sound-absorber unit or the sound-absorber assembly) is designed with a U-shaped recess (corresponding to the reference numeral 9) in its upper surface, into which U-shaped recess a steel band or other fastening band (corresponding to the reference numeral 50) can be inserted, which is fastened to the hub by pressing the sound-absorbing box-like structure against the hub around its circumference (see fig. 2). It is also possible, as required and as a matter of design, to arrange a plurality of cassette sound-absorbing structures on the hub, said steel band or other fastening band fixing several cassette sound-absorbing structures on the hub together around the hub. The joint of the steel belt or other fastening bands is fastened by a buckle, and the fastening force can be displayed by a fastening tool so as to judge the firmness of installation.

Fig. 4 is a graph of noise reduction measured by simulating acoustic behavior of a wheel/tire in one example of an application.

The design and adjustment of the geometric dimensions and sound absorption performance of the resonance sound absorption structure of the sound absorption device (or the sound absorber unit) shown in fig. 3 are carried out according to the geometric dimensions of the wheels/tires of a certain automobile in a driving state. The natural frequency of the tire air chamber is around 200 Hz. In this application example, in order to make the structural mode of the resonance sound absorption structure consistent with the natural mode of the tire air chamber, and achieve the purpose of structural resonance noise reduction, two sound absorber units 10 are connected in series at the closed end, and the two ends are connected through a thin plate B, so as to form a series three-layer resonance sound absorption structure (i.e. a sound absorber assembly formed by combining the two sound absorber units into a whole, for example, see fig. 3). In this example, the sound absorber unit/assembly is fabricated from a plastic material and is mounted symmetrically on the rim surface to form a pair of resonant sound absorbing structures, as shown in fig. 2.

When making an uproar volume of falling measure and calculate the experiment, install above-mentioned resonance sound absorbing structure in certain wheel according to above-mentioned mode, it is right to utilize finite element ACTRAN software's modal frequency response method the utility model discloses sound absorbing device's the volume of falling the noise is evaluateed. Firstly, respectively calculating the mode of the presence or absence of a sound absorption device of a wheel; then setting a sound source at the contact position of the tire and the ground based on the result of the mode; and finally, calculating the sound transmission of the sound source in the tire air chamber, keeping the wheel static, and positioning the measuring point at the top of the air chamber, so that a noise reduction effect graph of the resonance sound absorption structure shown in the figure 4 can be obtained.

It can be seen from fig. 4 that the effective noise reduction frequency band is 195-215 Hz, and the maximum noise reduction amount appears at 205Hz (near being in tire air chamber natural frequency), and the quantity value exceeds 12dB, thus the utility model discloses can reduce the noise that tire air chamber resonance produced effectively.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the above description of the embodiments is only provided to help understand the core concepts of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims (14)

1. A sound absorber unit (10) for mounting on a moving part in a gaseous environment for acoustic resonance reduction, characterized in that the sound absorber unit is constructed as a box of hexahedral shape and forms a three-layer helmholtz resonance sound absorbing structure with double and single holes combined, the box having two sides bounding the two ends of the box in the direction of movement of the moving part, one of the ends forming an open end side (D), having an opening into a cavity inside the box, and the other end forming a closed end side (D'); the interior of the box body is divided into a first cavity (2), a second cavity (5) and a third cavity (8) which are sequentially arranged along the moving direction of the moving part through a first partition plate (3) and a second partition plate (6); wherein the content of the first and second substances,

two first hollow tubes (1, 1') whose openings open into the gas atmosphere space are formed on the open-end side (D), said first hollow tubes extending into the first cavity (2) at a distance corresponding to their tube length;

a second hollow tube (4) opening into the first cavity (2) is formed in the first partition (3), said second hollow tube extending into the second cavity (5) at a distance corresponding to the tube length thereof;

two third hollow tubes (7, 7') are formed on the second partition (6), the openings of which open into the second cavity (5), said third hollow tubes extending into the third cavity (8) at a distance corresponding to the tube length thereof;

the first cavity (2), the second cavity (5) and the third cavity (8) form three resonant cavities with layered functions of the three-layer Helmholtz resonance sound absorption structure.

2. The sound absorber unit as claimed in claim 1, characterized in that the sound absorber unit (10) is an arc-shaped hexahedral box made of a metal material or a plastic material in one piece.

3. The sound absorber unit as claimed in claim 1, wherein the sound absorber unit (10) is an arc-shaped hexahedral box made of metal sheets or plastic sheets by splicing welding.

4. The sound absorber unit according to claim 1, wherein the first hollow tube (1, 1 '), the second hollow tube (4) and the third hollow tube (7, 7') are square tubes or circular tubes.

5. The sound absorber unit as claimed in any one of claims 1 to 4, wherein structural parameters of the housing of the sound absorber unit (10) are determined by the predetermined sound absorption coefficient and the sound absorption capacity of the three-layer Helmholtz resonance sound absorbing structure, the structural parameters including the plate thicknesses of the first and second partition plates (3, 6), the open end side (D) and closed end side (D '), the orifice diameters and tube lengths of the first hollow tube (1, 1 '), second hollow tube (4) and third hollow tube (7, 7 '), the shapes, the volumes and the wall thicknesses of the first cavity (2), the second cavity (5) and the third cavity (8).

6. A wheel equipped with sound-absorbing means for reducing acoustic resonances installed inside the wheel air chamber (30), said sound-absorbing means comprising at least one sound absorber unit (10) as claimed in any one of claims 1 to 5 or comprising at least one sound absorber assembly integrated by a plurality of said sound absorber units (10).

7. A wheel according to claim 6, characterized in that said sound absorber unit or said sound absorber assembly is bound to the hub (20) of the wheel by means of a binding element (50).

8. A wheel according to claim 7, characterized in that the sound absorber unit (10) or the sound absorber assembly itself forms a structural resonance sound absorber, as which the first order natural modal frequency coincides with the first order natural modal frequency of the wheel air chamber (30).

9. A wheel according to claim 7, characterized in that said tie element (50) is a tie strap which is pressed from the top face of the case of the sound absorber unit (10) or assembly against the outer face of the rim of the wheel hub and tightens said sound absorber unit (10) or assembly around the hub (20), the two ends of the tie strap being fixedly connected by snap fastening, the tension of the tie strap being adjustable and/or displayable by means of a tightening tool.

10. A wheel according to claim 9, wherein the sound absorber unit (10) or the sound absorber assembly is provided with a U-shaped groove (9) on the top face of its case for embedding the strap.

11. A wheel according to claim 6, characterized in that said sound absorber assembly is composed of two said sound absorber units (10) joined directly or joined by a thin plate (B) with their closed end sides (D').

12. A wheel according to claim 6, wherein a plurality of said sound absorber units (10) or said sound absorber assemblies are arranged side by side on the hub (20) of the wheel or distributed along the circumference of the hub.

13. A wheel according to any of claims 6 to 12, wherein the sound absorber unit (10) or the sound absorber assembly in the mounted state rests with the bottom surface of the housing against the outer surface of the rim of the hub (20).

14. A wheel according to claim 13, wherein said sound absorber unit (10) or said sound absorber assembly is provided with at least one bend extending transversely of its housing, said bend dividing the sound absorber unit or sound absorber assembly into at least two sections in the longitudinal direction of its housing, so as to conform the bottom surface of the housing to the circular arc-shaped contour of the outer surface of the rim in the mounted state.

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