CN213877567U - Sound absorber unit and vehicle wheel with sound absorber - Google Patents
Sound absorber unit and vehicle wheel with sound absorber Download PDFInfo
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- CN213877567U CN213877567U CN202020796901.7U CN202020796901U CN213877567U CN 213877567 U CN213877567 U CN 213877567U CN 202020796901 U CN202020796901 U CN 202020796901U CN 213877567 U CN213877567 U CN 213877567U
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Abstract
The application relates to a sound absorber unit and a vehicle wheel having a sound absorber device comprising at least one sound absorber unit (10) or at least one sound absorber module which is composed of a plurality of sound absorber units as a whole. The sound absorber unit is constructed into a box body in a cuboid shape, a two-hole double-layer Helmholtz resonance sound absorption structure is formed, and meanwhile, the sound absorber unit or the sound absorber assembly forms a structural resonance sound absorption device. 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
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 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 double-deck two hole 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 double-layer two-hole resonance sound absorption structure is adopted, and the defects that the low-frequency sound absorption capability is difficult to improve under the limited volume and the sound absorption frequency band is narrow in single Helmholtz resonance sound absorption are overcome on the control principle; secondly, a box-shaped structure in a shape of a cuboid 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, the sound absorption quantity is further increased on the basis of double-layer two-hole resonance sound absorption, and the sound absorption frequency band is expanded; and thirdly, a structure of two layers of hollow pipes is adopted, compared with the design of a plurality of hollow pipes, the control parameters are less, the structure is simpler, and the processing is more convenient.
In particular, the present invention provides a sound absorber unit to be mounted on a moving part (e.g. a hub of a wheel) in a gaseous environment for reducing acoustic resonance, characterized in that the sound absorber unit is constructed as a box body in the shape of a rectangular parallelepiped and forms a two-hole double-layer helmholtz resonance sound absorbing structure; the box body is provided with two side surfaces which limit the boundaries of the two ends of the box body in the moving direction of the moving part, wherein one end of the box body forms an opening end side surface and is provided with an opening which is communicated with the cavity in the box body, and the other end of the box body forms a closed end side surface; the interior of the box body is divided into a first cavity and a second cavity which are arranged in succession in the movement direction of the moving part by a partition plate, a nozzle of a first hollow tube is formed on the side of the open end, the nozzle of the first hollow tube opens into the gas environment space, the first hollow tube extends into the first cavity at a distance corresponding to the tube length thereof and terminates before the partition plate with a space, a nozzle of a second hollow tube is formed on the partition plate, the nozzle of the second hollow tube opens into the first cavity, the second hollow tube extends into the second cavity at a distance corresponding to the tube length thereof and terminates before the side of the closed end with a space, wherein, assuming that the first hollow tube is extended in the extension direction thereof and then intersects the partition plate to form a virtual area region, the nozzle of the second hollow tube is arranged on the partition plate at a position which is deviated from the area region, the first cavity and the second cavity form two resonant cavities with layered functions of the two-hole double-layer Helmholtz resonance sound absorption structure.
It should be noted that the "cuboid shape" in the present application is not strictly limited to a regular cuboid shape in a geometric sense, but may substantially have a shape similar to a cuboid, wherein one or more faces are configured to have a certain curvature (e.g., the bottom surface of the box body has a circular arc shape adapted to the outer surface profile of the rim) and/or have a local convex or concave structure (e.g., for installation or fixation), 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.
According to one embodiment, the first hollow tube extends in the first cavity over a tube length of 0.3 to 0.9 times the clearance between the open end side and the partition. The actual tube length dimension of the first hollow tube may be determined based on the specific structural design and acoustic properties.
According to one embodiment, the second hollow tube has at least one bend, so that the second hollow tube extends in the second cavity over a tube length of 0.6 to 2 times the clearance between the separating wall and the side of the closed end. The bend can be configured, for example, as a 60 to 120 degree bend. Preferably, the second hollow tube has a 90-degree bend at a position near the side of the closed end. By means of this bent or meandering design, the tube length of the second hollow tube extending in the second cavity can be increased, thus allowing an optimized adjustment of the acoustic properties of the system locally.
According to one embodiment, the offset of the geometric center of the orifice of the second hollow tube relative to the geometric center of the area region is 0.5 to 3 times the inner diameter of the first hollow tube. This effectively avoids the undesirable phenomenon of "acoustic short circuits".
According to one embodiment, it is advantageous that the structural parameters of the housing of the sound absorber unit, including the thickness of the partition and the plate body on the open-end side and the closed-end side, the orifice diameters and the tube lengths of the first hollow tube and the second hollow tube, the shape, volume and wall thickness of the first cavity and the second cavity, are determined by a predetermined sound absorption coefficient and sound absorption quantity of the two-hole double-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 a further embodiment, the restraining element is a carrier strip (for example a steel strip) to which the sound absorber unit or sound absorber module is pre-fixed to form a pre-assembled unit, which is tightened around the hub and around the outer surface of the rim.
In this connection, it is possible for the sound absorber unit or the sound absorber module to be fitted with its bottom side of the housing with the mounting surface of the carrier strip and adhesively fastened to the carrier strip, so that they are firmly joined to form a preassembled unit. The sound absorber unit or sound absorber assembly may also be secured to the carrier strip by suitable fasteners (e.g., tape, clips, screws, etc.).
According to one embodiment, the sound absorber assembly is formed by two sound absorber units which are connected with each other 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 chamber and the second chamber; 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.
Thus, according to the utility model discloses, alright realize one kind and install on wheel hub and be used for reducing the structure of wheel air chamber acoustic resonance. The box-type structure is a cuboid box-type structure, the interior of the box-type structure is divided into two cavities by a layer of thin plate, a hollow pipe is arranged (or constructed) on one side surface (parallel to the interior of the box-type structure), the interior of the box-type structure is also provided (or constructed) with a hollow pipe, the pipe orifice plane at one end of the first hollow pipe and the side surface of the box-type structure are on one surface, the pipe length extends into the cavity, the pipe orifice plane at one end of the second hollow pipe and the interior of the box-type structure are on one surface, the pipe length extends into the other cavity, and the hollow pipe can be bent by 90 degrees in the cavity due to the fact that the hollow pipe is long. The two hollow pipes of the structure are communicated with the tire air chamber and are arranged on the circumferential surface of a circular arc of the hub to form a two-hole double-layer Helmholtz resonance sound absorption structure. Compared with single-cavity single-hole type Helmholtz resonance sound absorption, the structure is easier to be designed to be close to low frequency, and the sound absorption frequency band is wider. And relevant parameters of the structure are determined by using the sound absorption coefficient and the sound absorption quantity of the double-layer Helmholtz resonance sound absorption structure.
The box-type structure is preferably made of plastic materials with certain rigidity and strength, clings to the circular arc circumference of the hub and is fixedly installed by utilizing a steel belt. In the structure in the installation mode, the first-order natural modal frequency of the structure is consistent with the first-order natural modal frequency of the wheel air chamber, and a structural resonance sound absorption structure is formed.
The natural mode of the structure meets the design requirements through plate thickness and shape adjustment, and the adjustment needs to be realized through finite element calculation. On one hand, the design of the sound absorption structure can further increase the sound absorption quantity of the two-hole double-layer resonance sound absorption structure, and the sound absorption bandwidth can also be further increased through the design.
This kind of box sound absorbing structure of constituteing by the double-deck resonance sound absorption of two holes and the structure resonance sound absorption, the upper surface can be designed and have the U-shaped recess, and this box structure's mounting means utilizes the steel band to pass through the U-shaped recess, and it is fixed to it around wheel hub a week. It is also possible to arrange a plurality of cassette sound-absorbing structures on the hub according to the actual needs and the specific design situation, and a steel belt is wound around the hub to fix the several cassette sound-absorbing structures on the hub together. The steel band junction is fastened with the buckle, and fastening force can show with fastening tool to judge the firm degree of installation.
The utility model discloses the beneficial technological effect that can realize lies in very much, by the synthetic sound absorbing structure that the double-deck resonance sound absorption of two holes and the resonance sound absorption of structure are constituteed, realizes more effective sound absorption effect, and this embodiment is in: firstly, the sound absorption frequency is easier to approach to the low frequency; secondly, the sound absorption frequency band is wider; thirdly, the sound absorption capacity is higher.
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 arranged on a wheel hub according to a first embodiment.
Fig. 3 is a schematic view of a sound absorber unit arranged on a wheel hub according to a second embodiment.
Fig. 4A is a schematic view of the principle of construction of a first embodiment of the sound absorber unit.
Fig. 4B is a schematic view of the construction principle of a second embodiment of the sound absorber unit.
Fig. 4C is a schematic view of the construction principle of a sound absorber assembly.
Fig. 5 is a perspective view of an acoustic absorber assembly in physical appearance.
FIG. 6 is a perspective view of an example wheel having a sound absorbing device showing a suction assembly secured to the hub of the wheel.
Figure 7 is a perspective view of the combination of the aspirator assembly and the restraining element used in the example of figure 6.
Fig. 8 is the road surface of the vehicle speed of 15km/h of being surveyed and is gone the test, equips resonance sound absorption structure at its wheel not, according to reference technology and equip resonance sound absorption structure and according to the utility model discloses under the three kinds of circumstances of equipment resonance sound absorption structure, the noise level spectrogram that the actual measurement obtained in the car.
Fig. 9 is the road surface of the vehicle speed of being surveyed and is gone the test, equips resonance sound absorption structure at its wheel not, according to reference technology and equip resonance sound absorption structure and according to the utility model discloses under the three kinds of circumstances of equipment resonance sound absorption structure, the noise level spectrogram that the actual measurement obtained in the car.
Wherein: 1-the side surface of the opening end of the box body, 1' -the side surface of the closed end of the box body, 2-a first hollow pipe, 3-a first cavity, 4-a partition board, 5-a second hollow pipe, 6-a second cavity and 7-a U-shaped groove; 8-first bend, 8' -second bend, 10-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," "fourth," 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.
The present application provides a sound absorber unit 10 to be mounted on a moving part (as shown in fig. 1, particularly a wheel hub 20 of an automobile wheel equipped with a pneumatic tire 40) in a gas environment (as shown in fig. 1, particularly a wheel air chamber 30) for reducing acoustic resonance, which is constructed as a box body having a rectangular parallelepiped shape and forms a two-hole double-layer helmholtz resonance sound absorbing structure, as shown in fig. 2 and particularly in fig. 4A and 4B; the box body is provided with two side surfaces which limit the boundaries of the two ends of the box body in the moving direction of the moving part, wherein one end of the box body forms an open end side surface 1 and is provided with an opening which is communicated with the cavity in the box body, and the other end of the box body forms a closed end side surface 1'; the interior of the box body is divided into a first cavity 3 and a second cavity 6 which are arranged in succession in the direction of movement of the moving part by a partition 4, a nozzle of a first hollow tube 2 is formed on the open end side 1, which nozzle opens into the gas atmosphere space, the first hollow tube extends into the first cavity 3 at a distance corresponding to its tube length and terminates with a gap before the partition 4, a nozzle of a second hollow tube 5 is formed on the partition 4, which nozzle opens into the first cavity 3, the second hollow tube extends into the second cavity 6 at a distance corresponding to its tube length and terminates with a gap before the closed end side 1', wherein, assuming that the first hollow tube 2 extends in its direction of extension and intersects the partition 4 to form a virtual area region, the orifice of the second hollow tube 5 is arranged on the partition plate 4 at a position deviated relative to the area, and the first cavity 3 and the second cavity 6 form two layered resonant cavities of the two-hole double-layer Helmholtz resonance sound absorption structure.
The first hollow tube 2 may have a tube length extending in the first cavity 3 of 0.3 to 0.9 times a clearance between the open end side 1 and the partition plate 4.
The second hollow tube 5 may have at least one bend such that the second hollow tube extends in the second cavity 6 with a tube length of 0.6 to 2 times the clearance between the partition 4 and the closed end side 1'. Preferably, the second hollow tube 5 has a 90-degree bend at a position close to the side surface 1' of the closed end.
Preferably, the deviation amount of the geometric center of the orifice of the second hollow tube 5 relative to the geometric center of the area region is 0.5 to 3 times the inner diameter of the first hollow tube 2.
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 two-hole double-deck helmholtz resonance sound absorption structure are confirmed, structural parameter includes baffle 4 with open end side 1 and blind end side 1' the plate body thickness the mouth of pipe aperture and the pipe length of first hollow tube 2 and second hollow tube 5 the shape, volume and the wall thickness of first cavity 3 and second cavity 6. This will be further explained below.
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.
The sound absorber unit 10 or the sound absorber assembly may be integrally formed of a metal material or a plastic material. 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. This will be further explained below.
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 and 3).
Fig. 2 is a schematic view of a sound absorber unit arranged on a wheel hub according to a first embodiment. Accordingly, the binding element 50 is a binding band (e.g., a steel band) which is pressed from the top surface of the case of the sound absorber unit 10 or the sound absorber module against the outer surface of the rim of the wheel hub and fastens the sound absorber unit 10 or the sound absorber module around the hub 20, both ends of the binding band are fixedly connected by a snap, and the tension of the binding band can be set and/or displayed by means of a fastening tool. Suitably, the sound absorber unit 10 or the sound absorber module is provided with a U-shaped groove 7 on the top face of its case for inserting the strap (see fig. 4A).
As an alternative to the fastening of the sound absorber unit or sound absorber module to the wheel hub by means of a fastening element, the fastening element 50 can also be designed as a carrier band to which the sound absorber unit 10 or sound absorber module is fastened beforehand to form a preassembled unit, which is then placed around the wheel hub and tightened around the outer surface of the wheel rim to fasten the preassembled unit. In order to form the preassembly unit, the sound absorber unit 10 or the sound absorber assembly is matched with the surface of the bearing belt by the bottom surface of the box body and is fixedly adhered to the bearing belt; alternatively, the sound absorber unit 10 or sound absorber assembly is secured to the carrier strip by fasteners (e.g., tape, clips, screws, etc.).
Fig. 3 is a schematic view of a sound absorber unit arranged on a wheel hub according to a second embodiment, wherein two sound absorber units (or sound absorber modules) are arranged symmetrically in the circumferential direction of the hub, i.e. mounted opposite each other in the wheel diameter direction.
FIGS. 4A and 4B show the general configuration and internal construction of a single sound absorber unit, wherein the first embodiment of the sound absorber unit shown in FIG. 4A is provided with a groove in the top surface of the case, particularly adapted for assembly and securing with a strap according to the embodiment shown in FIGS. 2 and 3; the second embodiment of the sound absorber unit shown in fig. 4B is simple and neat in shape and convenient to manufacture and store. Fig. 4C exemplarily shows the general external structure and internal configuration of the sound absorber assembly composed of two sound absorber units, and as shown, the sound absorber assembly may be composed of two said sound absorber units 10 joined with their closed-end sides 1'.
Preferably, the sound absorber unit 10 (see fig. 4A and 4B) or the sound absorber assembly (see fig. 4C) is a cuboid-shaped box integrally made of a plastic material and may be manufactured by a 3D printing process, thereby allowing for an efficient, flexible production of the sound absorber unit and/or the sound absorber assembly.
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, it is expedient if the sound absorber unit 10 or the sound absorber module is provided with at least one bend extending transversely to its housing, which divides the sound absorber unit or the sound absorber module in its longitudinal direction 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 mounted state, as shown in fig. 5. For the sound absorber unit, for example, a second fold 8' may be provided between the first and second chambers (see fig. 5); for the sound absorber assembly, for example, a first fold 8 (see fig. 5) can additionally be provided at the connection point of the sound absorber unit. 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.
Specifically, fig. 4A and 4B show an embodiment of the sound absorber unit of the present invention, which is embodied as a box-shaped structure in a rectangular parallelepiped shape processed by injection molding. The interior of the box-type structure is divided into two cavities, namely a first cavity 3 and a second cavity 6, by a layer of thin plate (a partition plate 4), a pipe orifice of a hollow pipe (namely a first hollow pipe 2) is formed on one side surface 1 (parallel to the interior of the box-type structure) of the box-type structure, and a pipe orifice of a hollow pipe (namely a second hollow pipe 5) is also formed on the interior of the box-type structure. The pipe orifice plane of one end of the first hollow pipe 2 and the side 1 of the box-shaped structure are on one face, the pipe length extends into the first cavity 3, the pipe orifice plane of one end of the second hollow pipe 5 and the interior division thin plate (the partition plate 4) are on one face, the pipe length extends into the second cavity 6, the second hollow pipe is installed in the second cavity 6 in a manner of deviating to one side, the second hollow pipe is prevented from being opposite to the first hollow pipe 1, and the second hollow pipe has a section bent by 90 degrees in the second cavity 6. The first hollow tube 2 of the resonance sound absorbing box structure shown in fig. 4A and 4B communicates with the wheel air chamber (or tire air chamber) 30 shown in fig. 1, and is installed on the circular arc circumference of the hub 20 shown in fig. 1 to form a two-hole double-layer helmholtz resonance sound absorbing structure.
Relevant parameters of the box structure having a rectangular parallelepiped shape shown in the drawing are determined using the sound absorption coefficient and the sound absorption amount of the double-layer helmholtz resonance sound absorbing structure, as described in the following equation:
z is the acoustic impedance of the resonant structure. Zp1Acoustic impedance of the holes of the perforated structure of the first layer, Za1The acoustic impedance of the cavity of the first layer. Zp2Acoustic impedance of the holes of the perforated structure of the second layer, Za2The acoustic impedance of the cavity of the second layer.
Where ρ is an air density, c is an air sound velocity, ω is 2 pi f, and f is a frequency. Gamma is air motion viscosity coefficient, gamma is 15 × 10-6m2/s。t1And t2Thickness of the first and second layer, respectively, d1And d2The respective apertures of the first and second layers, δ1And delta2The perforation rates, D, of the first and second plies, respectively1And D2The thicknesses of the first layer and second layer cavities, respectively.
ZrIs the relative specific acoustic impedance of the resonant structure.
Let R be ZrThe real part of (A), X is ZrThe sound absorption coefficient alpha of the resonance sound absorption structure is as follows:
the sound absorption quantity calculation formula is as follows:
A＝αs (2)
wherein: and A is the sound absorption quantity of the resonance sound absorption structure.
And S is the cross-sectional area of the first hollow pipe 2 of the resonance sound absorption structure.
The box-shaped structure with a cuboid shape is used as a resonance sound absorption structure, and the first-order natural modal frequency of the box-shaped structure is consistent with the first-order natural modal frequency of the wheel air chamber. The natural frequency of the steel plate reaches the design requirement through plate thickness and shape adjustment, and the adjustment mode of the steel plate needs to be realized through finite element calculation.
As an example, fig. 2 shows a first embodiment in which the sound absorber unit is arranged on the wheel hub. The two-hole double-layer resonance sound absorbing structure shown in fig. 4A is designed with a U-shaped groove 7 on the upper surface thereof in order to mount the sound absorbing structure on the hub 20 shown in fig. 1. As shown in fig. 2, the installation method is as follows: the steel belt is used as a binding belt to pass through and be embedded into the U-shaped groove 7, and the resonance sound absorption structure is tightly pressed on the hub around the periphery of the hub to be fixed. The steel band may be fastened to the hub around its circumference by one or more sound-absorbing structures. The steel band junction is fastened with the buckle, and fastening force can show with fastening tool to judge the firm degree of installation.
As an example, fig. 3 shows a second embodiment in which the sound absorber unit is arranged on the wheel hub. In the application example shown in fig. 6, the natural frequency of the SUV vehicle, particularly the air chamber deformation geometry in the driving state, is calculated by using a commercial software, and for the natural frequency, the geometry and the sound absorption performance of the resonance sound absorption structure shown in fig. 4A or fig. 4B are designed and adjusted according to the formula (1) and the formula (2). Because the inherent structure mode of a single resonance sound absorption structure is higher, in order to enable the structure mode of the resonance sound absorption structure to be consistent with the inherent mode of a tire air chamber and achieve the purpose of structure resonance noise reduction, two resonance sound absorption structures (namely the sound absorber unit 10) are connected together at the closed end, and the geometric dimension of the inherent frequency of the whole connected structure is adjusted by a numerical simulation means, so that the design of the resonance sound absorption structure is completed. In this case, a plastic material is used to fabricate a resonant sound absorption structure object ("sound absorber unit" or "sound absorber assembly") by 3D printing, and two sound absorber units are combined together as shown in fig. 5 to form a sound absorber assembly (that is, a pair of sound absorber units forms a sound absorber assembly). Two sound absorber assemblies (i.e., two pairs of sound absorber units in total) are mounted on the rim surface, and the two sound absorber assemblies are symmetrically mounted on the rim surface, as shown in fig. 7. It is possible to pre-fix the two sound absorber modules to the tie-down element to form a pre-assembled unit (in which case the tie-down element acts as a carrier band, for example steel strips may be used) and then to assemble and fix the pre-assembled unit to the wheel hub.
With the SUV car is as being surveyed the vehicle, do not equip resonance sound absorbing structure at its wheel respectively, equip resonance sound absorbing structure according to the reference technique and according to the utility model discloses equip under three kinds of circumstances of resonance sound absorbing structure, carry out road surface operating mode under 15km/h and 30km/h speed of a motor vehicle and travel, carry out the interior noise characteristic actual measurement contrast of car, the measurement station is located the copilot position. Fig. 8 shows the measured vehicle in the road surface driving test of the speed of a vehicle 15km/h, not equip resonance sound absorption structure at its wheel, equip resonance sound absorption structure according to the reference technique and according to the utility model discloses equip under three kinds of circumstances of resonance sound absorption structure, the noise level spectrogram that the actual measurement obtained in the car. Fig. 9 shows that the measured vehicle is in the road surface of speed of a motor vehicle 30km/h test of traveling, equips resonance sound absorption structure at its wheel not, according to reference technology and equip resonance sound absorption structure and according to the utility model discloses under three kinds of circumstances of equipment resonance sound absorption structure, the noise level spectrogram that the actual measurement obtained in the car. Here, the process is repeated. Each of the four wheels is provided with two pairs of the resonance sound absorption structures (see fig. 7), for a total of eight pairs. And carrying out real vehicle test on a rough road surface. In fig. 8 and 9, the graph "III" is a noise level spectrum chart in the vehicle when the tested vehicle is not equipped with the resonance sound absorption structure, the graph "I" is an installation of the noise level spectrum chart in the vehicle when the resonance sound absorption structure, and the graph "II" is a noise level spectrum chart in the vehicle when another resonance sound absorption structure is installed (for comparison reference only). It can be seen from the figure that the noise peak value that produces by tire air chamber resonance in the car near 200Hz is outstanding, install the utility model discloses after resonance sound absorption structure, the peak value reduces by a wide margin, and the maximum value is about 8dB (A), has reduced 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 (16)
1. A sound absorber unit (10) to be mounted on a moving part in a gaseous environment for reducing acoustic resonance, characterized in that said sound absorber unit is constructed as a box in the shape of a rectangular parallelepiped and forms a two-hole double-layer helmholtz resonance sound absorbing structure; the box body is provided with two side surfaces which limit the boundaries of the two ends of the box body in the moving direction of the moving part, wherein one end forms an open end side surface (1) which is provided with an opening leading into the cavity in the box body, and the other end forms a closed end side surface (1'); the interior of the box body is divided into a first cavity (3) and a second cavity (6) which are arranged in succession in the movement direction of the moving part by a partition (4), a nozzle of a first hollow tube (2) which opens into the gas atmosphere space is formed on the open-end side (1), the first hollow tube extends into the first cavity (3) at a distance corresponding to the tube length thereof and terminates with a gap before the partition (4), a nozzle of a second hollow tube (5) which opens into the first cavity (3) is formed on the partition (4), the second hollow tube extends into the second cavity (6) at a distance corresponding to the tube length thereof and terminates with a gap before the closed-end side (1'), wherein the first hollow tube (2) after extension in the extension direction thereof intersects the partition (4) to define a virtual area region, the pipe orifice of the second hollow pipe (5) is arranged on the partition board (4) at a position deviated relative to the area, and the first cavity (3) and the second cavity (6) form two layered resonant cavities of the two-hole double-layer Helmholtz resonance sound absorption structure.
2. The sound absorber unit (10) as claimed in claim 1, wherein the first hollow tube (2) extends in the first cavity (3) over a tube length of 0.3 to 0.9 times the clearance between the open end side (1) and the partition (4).
3. The sound absorber unit (10) as claimed in claim 1, wherein the second hollow tube (5) has at least one bend such that it extends in the second cavity (6) over a tube length of 0.6 to 2 times the clearance between the partition (4) and the closed end side (1').
4. The sound absorber unit (10) as claimed in claim 3, wherein the second hollow tube (5) has a 90 degree bend at a location adjacent the closed end side (1').
5. The sound absorber unit (10) as claimed in claim 1, wherein the orifice geometric center of the second hollow tube (5) is offset with respect to the area geometric center by an amount of 0.5 to 3 times the inner diameter of the first hollow tube (2).
6. The sound absorber unit (10) as claimed in any one of claims 1 to 5, wherein structural parameters of the housing of the sound absorber unit (10) are determined by a predetermined sound absorption coefficient and sound absorption capacity of the two-hole double-layer Helmholtz resonance sound absorbing structure, the structural parameters including the panel thickness of the partition plate (4) and the open end side (1) and closed end side (1'), the orifice diameters and tube lengths of the first hollow tube (2) and second hollow tube (5), the shape, volume and wall thickness of the first cavity (3) and second cavity (6).
7. A wheel equipped with sound-absorbing means mounted inside the wheel air chamber (30) for reducing acoustic resonances, characterized in that said sound-absorbing means comprise at least one sound absorber unit (10) according to any one of claims 1 to 6 or at least one sound absorber assembly integrated by a plurality of said sound absorber units (10).
8. A wheel according to claim 7, 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).
9. A wheel according to claim 8, wherein the sound absorber unit (10) or the sound absorber assembly is made of a metal material or a plastic material in one piece and forms itself 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).
10. A wheel according to claim 8, 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.
11. A wheel according to claim 10, wherein said sound absorber unit (10) or said sound absorber assembly is provided with a U-shaped groove (7) on the top face of its case for embedding said strap.
12. A wheel according to claim 8, characterized in that said restraining element (50) is a carrier tape to which said acoustic absorber unit (10) or assembly is pre-fixed to form a pre-assembled unit, which is tightened around the hub and around the outer surface of the rim to secure said pre-assembled unit.
13. A wheel according to claim 7, characterized in that said sound absorber assembly is composed of two said sound absorber units (10) joined by their closed end sides (1').
14. A wheel according to claim 7, 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.
15. A wheel according to any of claims 7 to 14, 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).
16. A wheel according to claim 15, wherein said sound absorber unit (10) or said sound absorber assembly is provided with at least one bend extending transversely of its casing, said bend dividing the sound absorber unit or sound absorber assembly in its longitudinal direction of the casing into at least two sections in order to conform the bottom surface of the casing to the circular arc-shaped contour of the outer surface of the rim in the mounted state.
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| CN202020796901.7U CN213877567U (en) | 2020-05-14 | 2020-05-14 | Sound absorber unit and vehicle wheel with sound absorber |
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| CN202020796901.7U CN213877567U (en) | 2020-05-14 | 2020-05-14 | Sound absorber unit and vehicle wheel with sound absorber |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113674728A (en) * | 2020-05-14 | 2021-11-19 | 中信戴卡股份有限公司 | Sound absorber unit and vehicle wheel with sound absorber |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113674728A (en) * | 2020-05-14 | 2021-11-19 | 中信戴卡股份有限公司 | Sound absorber unit and vehicle wheel with sound absorber |
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