Vehicle sound absorption structure
A vehicle sound absorption structure has: a recessed cell that has an opening on one end of the cell; a divider that is provided within the cell and that divides an acoustic wave entering the cell from the opening into two acoustic waves; reflectors that reflect one of the two acoustic waves divided at the divider and reflect the other acoustic wave respectively toward the opening, and that generate a phase difference between the one acoustic wave and the other acoustic wave; and an interfering portion that is provided within the cell and that causes the one acoustic wave and the other acoustic wave, which have been respectively reflected at the reflectors, to interfere with each other.
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1. Field of the Invention
The present invention relates to a vehicle sound absorption structure.
2. Description of Related Art
Japanese Utility Model No. 3048125 (JP-U-3048125) discloses an acoustic insulation material that is intended to prevent noise, such as engine sound generated in the engine compartment, road noise generated during driving, and wind whistle sound, from entering the car cabin through the door seal. The acoustic insulation material, when in use, is fitted onto the cross section of the front fender of the car. The acoustic insulation material uses a cushion material that has a predetermined density. The cushion material is either coated with a film or not coated with any film, but subjected to waterproof treatment.
As described in JP-U-3048125, the special cushion material that has a predetermined density is coated with a film or is subjected to waterproof treatment on the surface of the cushion material. However, this causes an increase in costs of the cushion material, an increase in number of parts, and an increase in processing costs and management costs.
SUMMARY OF THE INVENTIONThe present invention provides a low-cost vehicle sound absorption structure.
A first aspect of the present invention is related to a vehicle sound absorption structure that has: a recessed cell that has an opening on one end thereof; a divider that is provided within the cell and that divides an acoustic wave entering the cell from the opening into two acoustic waves; reflectors that reflect one of the two acoustic waves divided at the divider and reflect the other acoustic wave respectively toward the opening, and that generate a phase difference between the one acoustic wave and the other acoustic wave; and an interfering portion that is provided within the cell and that causes the one acoustic wave and the other acoustic wave, which have been reflected respectively at the reflectors, to interfere with each other.
According to the first aspect of the invention, an acoustic wave enters the cell from the opening of the cell and is divided at the divider into two acoustic waves. When the two acoustic waves are reflected respectively at the reflectors, a phase difference is generated between the one acoustic wave and the other acoustic wave. The one acoustic wave and the other acoustic wave interfere with each other at the interfering portion, while having the phase difference, so that a sound absorption effect is produced. This allows the vehicle sound absorption structure to be provided at low cost without increasing the number of parts.
According to the first aspect of the invention, an end of the divider on the side of the opening may be positioned more inward in the cell than the opening and positioned closer to the opening than one of the reflectors. The one of the reflectors may be positioned closer to the opening than the other reflector. The interfering portion may be positioned between the end and the opening.
As described above, the vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of providing the low-cost vehicle sound absorption structure.
In the above aspect, the divider may have an end on the side of the opening and positioned more inward in the cell than the opening, while being positioned closer to the opening than one of the reflectors, the one of the reflectors being positioned closer to the opening than the other reflector. And, the interfering portion may be positioned between the opening and the end of the divider. This allows an acoustic wave that enters the cell to be absorbed in the cell.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of producing the sound absorption effect in the cell in a stable manner.
In the first aspect of the invention, the vehicle sound absorption structure may further include a cover member that covers the opening. The cover member may have a slit that is provided on an extension of the divider.
According to the first aspect of the invention, when incident acoustic waves obliquely to the depth direction of the cell enter the cell through the slit, the acoustic waves become in phase due to a diffraction phenomenon through the slit. This ensures that the one acoustic wave and the other acoustic wave that are divided at the divider have a desired phase difference therebetween. Therefore, the vehicle sound absorption structure has improved sound absorption performance with respect to the acoustic wave frequency of the sound to be absorbed.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of improving the sound absorption performance with respect to the acoustic wave frequency of the sound to be absorbed.
In the first aspect of the invention, the slit may extend in a direction along the end of the divider.
As described above, the slit extends in a direction along the end of the divider. Thus, when acoustic waves enter the cell through the slit, the acoustic waves become in phase over a wide frequency range due to a diffraction phenomenon. Therefore, the vehicle sound absorption structure has further improved sound absorption performance with respect to the acoustic wave frequency of the sound to be absorbed.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of further improving the sound absorption performance with respect to the acoustic wave frequency of the sound to be absorbed.
In the first aspect of the invention, the cell may be partitioned by a wall that includes a base part and the other part, and the base part may be thinner than the other part.
As described above, the cell is partitioned by a wall that includes a base part and the other part, and the base part is thinner than the other part. Thus, upon the entry of an acoustic wave into the cell, film resonance occurs on the wall that partitions the cell. Due to the film resonance, energy of the acoustic wave is converted into kinetic energy, so that the sound is absorbed. This further improves the sound absorption performance.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of further improving the sound absorption performance.
In the first aspect of the invention, the vehicle sound absorption structure may also serve as a fender protector that shields a gap between a vehicle body framework and a rear end of a front fender panel, the rear end being positioned inner side of the vehicle. The opening may be formed toward the front side of the vehicle.
The vehicle sound absorption structure according to the first aspect of the invention also serves as a fender protector, and the opening is formed toward the front side of the vehicle. This allows noise from a front tyre to be absorbed without increasing the number of parts.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of absorbing the noise from the front tyre without increasing the number of parts.
In the first aspect of the invention, the vehicle sound absorption structure may be provided on a front surface of the fender protector that shields the gap between the vehicle body framework and the rear end of the front fender panel, in which the front surface faces toward the front side of the vehicle, and the rear end is positioned inner side of the vehicle.
As described above, the vehicle sound absorption structure is provided on the front surface of the fender protector, the front surface facing toward the front side of the vehicle. This enables the noise from the front tyre to be absorbed.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of absorbing road noise from the front tyre.
In the first aspect of the invention, the vehicle sound absorption structure may be formed in combination with the fender protector. The front surface of the fender protector may be utilised as the reflectors, and the front surface faces toward the front side of the vehicle.
As described above, the front surface of the fender protector is utilised as the reflectors. This enables reductions in material costs of and in weight of the vehicle-sound absorption structure, compared to the case when the reflector is continuously formed with a wall of the cell.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of reducing the material costs and the weight, compared to the case when the reflector is continuously formed with a wall of the cell.
In the first aspect of the invention, the vehicle sound absorption structure may also serve as at least one of an engine cover and a floor under cover.
In the first aspect of the invention, the vehicle sound absorption structure may also serve as a fender liner that is formed on an inside of the front fender panel to cover the front tyre. The opening may be formed toward the front side of the vehicle.
In the first aspect of the invention, a plurality of the cells may be arranged in parallel in a vertical direction with the opening of each of the cells facing toward the front side of the vehicle. Communicating holes communicate with a lower adjacent one of the cells may be formed on lower walls of the cells.
As described above, a plurality of the cells are arranged in parallel in a vertical direction with the opening of each of the cells facing toward the front side of the vehicle. This allows the sound absorption effect to be produced in a wide region. In addition, the cells each have lower walls through which communication holes are formed. The communication holes communicate with a lower adjacent one of the cells. This provides an additional function as an expansion silencer. Further, water in the cell can be drained through the communication holes. This further improves the sound absorption performance, while preventing the water from remaining in the cell to maintain the sound absorption performance.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of further improving the sound absorption performance, while preventing the water from remaining in the cell to maintain the sound absorption performance.
In the first aspect of the invention, the lower walls may be angled downwardly to the front side of the vehicle.
As described above, the lower walls of the cell are angled downwardly to the front side of the vehicle. This makes it difficult for the water to remain in the cell.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of making it difficult for the water to remain in the cell.
In the first aspect of the invention, the communication holes may be provided on the lower walls at respective ends that face toward the rear side of the vehicle.
As described above, the communication holes are provided on the lower walls at respective ends that face toward the rear side of the vehicle. Thus, when the vehicle is accelerating, the water in the cell flows toward the rear side of the vehicle to be efficiently discharged out of the cell through the communication holes.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of efficiently discharging the water flowing in the cell toward the rear side of the vehicle out of the cell through the communication holes when the vehicle is accelerating.
In the first aspect of the invention, the vehicle sound absorption structure may further include a Helmholtz resonator that is provided adjacent to the cells and that has a neck and a cavity, and the neck may be open in the same direction as the opening. The neck may be an opening of the Helmholtz resonator. This opening may be defined by the walls.
According to the first aspect of the invention, the Helmholtz resonator is provided adjacent to the cells to further improve the sound absorption performance.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of further improving the sound absorption performance by using the Helmholtz resonator that is provided adjacent to the cells.
In the first aspect of the invention, a volume of the cavity, a diameter of the neck or a length of the neck may be varied in order to adjust sound-absorption characteristics of the Helmholtz resonator.
In the first aspect of the invention, the cavity may be formed into a trapezium or trapezoid shape.
In the first aspect of the invention, the vehicle sound absorption structure may further has: a primary tubular passage that is provided adjacent to the cells and is open toward the same direction as the opening; and a secondary tubular passage that is branched from the primary tubular passage at a midsection of the primary tubular passage and that rejoins the primary tubular passage at a point where the primary tubular passage and the secondary tubular passage join together. The primary tubular passage and the secondary tubular passage may respectively have predetermined lengths such that an acoustic wave passing through the primary tubular passage alone and another acoustic wave passing through the primary tubular passage via the secondary tubular passage have a phase difference therebetween at the point where the primary tubular passage and the secondary tubular passage join together.
As described above, the acoustic wave passing through the primary tubular passage alone and the another acoustic wave passing through the primary tubular passage via the secondary tubular passage have a phase difference therebetween, and then interfere with each other at the point where the primary tubular passage and the secondary tubular passage join together. Consequently, the sound absorption effect is produced. This still further improves the sound absorption performance.
The vehicle sound absorption structure according to the first aspect of the invention has an excellent effect of still further improving the sound absorption performance.
A second aspect of the present invention is related to a front fender structure that has: a front fender panel; a fender protector that shields a gap between a vehicle body framework and a rear end of the front fender panel, the rear end facing toward the inner side of the vehicle; and a vehicle sound absorption structure according to the first aspect of the invention, the vehicle sound absorption structure being mounted onto a front surface of the fender protector with the opening facing toward the front side of the vehicle, the front surface facing toward the front side of the vehicle.
According to the second aspect of the invention, noise from the front tyre is absorbed at low cost.
The vehicle sound absorption structure according to the second aspect of the invention has an excellent effect of absorbing noise from the front tyre at low cost.
In the second aspect of the invention, a plurality of the cells may be arranged in parallel in the vertical direction, the cells may each have lower walls through which communication holes are formed, and the communication holes may communicate with a lower adjacent one of the cells.
As described above, a plurality of the cells are arranged in parallel in the vertical direction. This allows the sound absorption effect to be produced in a wide region. In addition, the cells each have lower walls through which communication holes are formed. The communication holes communicate with a lower adjacent one of the cells. This provides an additional function as an expansion silencer. Further, water in the cell can be drained through the communication holes. This further improves the sound absorption performance, while preventing the water from remaining in the cell to maintain the sound absorption performance.
The vehicle sound absorption structure according to the second aspect of the invention has an excellent effect of further improving the sound absorption performance, while preventing the water from remaining in the cell to maintain the sound absorption performance.
Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[First Embodiment] As illustrated in
As illustrated in
The dividers 14 each are provided within the cell 12 to divide an acoustic wave that enters the cell 12 from the opening 24 into two acoustic waves. The divider 14 extends is positioned, for example, in the vehicle width direction between the left and right walls 26. The divider 14 has an end 14A on the side of the opening 24 and positioned more inward in the cell 12 than the opening 24. In other words, the end 14A is positioned more inward than a plane (not illustrated) that connects the walls 26 at their ends on the side of the openings 24. Also, the end 14A is positioned closer to the opening 24 than the reflector 16. The reflector 16 is positioned closer to the opening 24 than the reflector 18.
The divider 14 divides an acoustic wave into one acoustic wave 32 and the other acoustic wave 34. The reflectors 16 and 18 are designed respectively to reflect the one acoustic wave 32 and the other acoustic wave 34 toward the opening 24. The reflectors 16 and 18 are also designed to generate a phase difference between the one acoustic wave 32 and the other acoustic wave 34. A depth from the opening 24 to the reflector 18 is greater than a depth from the opening 24 to the reflector 16.
As illustrated in
It should be understood that, as illustrated in FIG, 5, a wall 27 may extend to the opening 24 in a fashion similar to the wall 26, and may have a window 27A that serves as the interfering portion 22. Then, an innermost one of the edges of the window 27A in the cell 12 may be the end 14A of the divider 14.
As illustrated in
It should be understood that in the case the sound to be absorbed has plural frequencies, the cells 12 can have different structures that correspond to various wavelengths λ of the plural frequencies, and these cells 12 can be used in combination.
As illustrated in
The front fender panel 36 is a member that forms a front outside surface of the vehicle. An arch-shaped fender liner 52 is mounted to the inside of the front fender panel 36. The fender liner 52 covers a front tyre 44.
As illustrated in FIG, 8, the vehicle body framework 46 is, for example, a front pillar on which a door 56 is mounted through a hinge 58. The vehicle sound absorption structure 10 also serves as the fender protector. This prevents water from entering through the gap 48, adhering to the hinge 58, and freezing in cold climates.
The vehicle sound absorption structure 10 is mounted using, for example, a clip (not illustrated) such that the vehicle sound absorption structure 10 shields the gap 48 between the vehicle body framework 46 and the rear end 36A of the front fender panel 36. The rear end 36A is positioned on an inner side of the vehicle. This mounting condition ensures a gap 62 between the fender liner 52 and the vehicle sound absorption structure 10. As illustrated in
The vehicle sound absorption structure 10 according to the first embodiment of the invention has the aforementioned configuration, and the effect of vehicle sound absorption structure 10 will be described below. As illustrated in
Specifically, when λ is the wavelength of the acoustic wave frequency of the sound to be absorbed and a difference between the depth from the opening 24 to the reflector 16 and the depth from the opening 24 to the reflector 18 (the distance from the reflector 16 to the reflector 18) is equal to λ/4, an acoustic wave that enters the cell 12 from the opening 24 is divided at the divider 14 into the two acoustic waves 32 and 34. Then, these acoustic waves 32 and 34 are reflected at the respective reflectors 16 and 18. This results in a phase difference of 2×λ/4=λ/2 (a half wavelength) between the acoustic waves 32 and 34 after the reflection, where the acoustic waves 32 and 34 interfere with each other at the interfering portion 22.
The one acoustic wave 32 and the other acoustic wave 34 that have the phase difference of a half wavelength therebetween interfere with each other, and cancel each other out, at the interfering portion 22. This results in the maximum sound absorption coefficient with respect to the acoustic wave frequency of the sound to be absorbed, as illustrated in
As described above, according to the first embodiment of the invention, the vehicle sound absorption structure 10 is provided at low cost without increasing the number of parts.
As illustrated in
It should be understood that the vehicle sound absorption structure 10 is not limited to the one that is used as a fender protector, but may also be applied to various components of the vehicle, such as an engine cover (not illustrated), a floor under cover (not illustrated), and the fender liner 52. It should also be understood that the vehicle sound absorption structure 10 may be formed on at least one of the fender protector, the engine cover, the floor undercover, and the fender liner 52.
[Second Embodiment] As illustrated in
Other portions of the vehicle sound absorption structure 20 are the same as those according to the first embodiment. Therefore, in the drawings, like numerals are used to represent like elements, and the description of the like elements is not repeated.
The vehicle sound absorption structure 20 according to the second embodiment of the invention has the aforementioned configuration, and the effect of vehicle sound absorption structure 20 will be described below. An acoustic wave can be incident from any direction relative to the cell 12 in a random manner. In the structure according to the first embodiment, an acoustic wave is obliquely incident to the depth direction of the cell 12, and accordingly, peaks 68 and troughs 70 (wavefronts) of the acoustic wave enter the cell 12 in the oblique direction. This does not always result in a distance difference of a half wavelength between the distance from the wavefronts to the reflector 16 and the distance from the wavefronts to the reflector 18.
However, as illustrated in
According to the second embodiment of the invention, the slit 64 extends in the direction along the end 14A of the divider 14 or in the vehicle width direction. Thus, when an acoustic wave enters the cell 12 through the slit 64, the phases of the acoustic waves 32 and 34 are matched over a wide frequency range. Therefore, as illustrated by a solid line in
[Third Embodiment] As illustrated in
The walls 26 each connect to the reflector 16 or 18 at the base part 2613 26B. The base part 26B is positioned deeper in the cell 12. The sound absorption performance obtained from the film resonance on the walls 26 can be controlled by varying a thickness t and a length L of the base part 26B. Specifically, as the thickness t of the base part 26B decreases or as the length L of the base part 2613 26B increases, the rigidity of the base part 26B decreases, so that a lower resonance frequency may be predetermined. In contrast, as the thickness t of the base part 26B increases or as the length L of the base part 26B decreases, the rigidity of the base part 26B increases, so that a higher resonance frequency may be predetermined.
As illustrated in
Other portions of the vehicle sound absorption structure 30 are the same as those according to the first embodiment. Therefore, in the drawings, like numerals are used to represent like elements, and the description of the like elements is not repeated. In addition, the third embodiment of the invention may be combined with at least one of the first and the second embodiments of the invention.
The vehicle sound absorption structure 30 according to the third embodiment of the invention has the aforementioned configuration, and the effect of vehicle sound absorption structure 30 will be described below. As illustrated in
In addition, as the rigidity of the base part 26B of the wall 26 decreases, the vehicle sound absorption structure 30 deforms more easily upon a collision of the vehicle. This ensures shock absorbing performance upon a collision of the vehicle.
Fourth Embodiment
As illustrated in
The Helmholtz resonator 80 is provided between the two adjacent cells 12. The two adjacent cells 12 are arranged symmetrically such that their respective reflectors 16 are adjacent to each other to form a space on the backside of the reflectors 16. This space is closed by a wall 38 to define the cavity 82. The wall 38 is continuously formed, for example, with the reflectors 18.
The Helmholtz resonator 80 has sound-absorption characteristics that can be adjusted, for example, by varying a volume of the cavity 82 or a diameter ND of the neck 78 as illustrated in
Other portions of the vehicle sound absorption structure 40 are the same as those according to the first embodiment. Therefore, in the drawings, like numerals are used to represent like elements, and the description of the like elements is not repeated. In addition, the fourth embodiment of the invention may be combined with at least one of the first, the second, and the third embodiments of the invention.
The vehicle sound absorption structure 40 according to the fourth embodiment of the invention has the aforementioned configuration, and the effect of vehicle sound absorption structure 40 will be described below. As illustrated in
In addition, according to the fourth embodiment of the invention, the Helmholtz resonator 80 is provided adjacent to the cells 12. This further improves the sound absorption performance. Specifically, the wall 38 or the bottom of the cavity 82 can be positioned as illustrated by a dot-and-dash line in
Secondly, the wall 38 or the bottom of the cavity 82 can be positioned as illustrated by a dotted line in
Thirdly, the wall 38 or the bottom of the cavity 82 can be positioned as illustrated by a chain double-dashed line in
[Fifth Embodiment] As illustrated in
The primary tubular passage 84 is provided adjacent to the cells 12 and is open toward the same direction as the opening 24. The secondary tubular passage 86 is branched from the primary tubular passage 84 at its midsection and rejoins the primary tubular passage 84. The secondary tubular passage 86 is formed, for example, along the backside of the reflector 16, along a wall 96, and then along the wall 38. The wall 96 is continuously formed with the divider 14. The wall 38 is continuously formed with the reflector 18. Additionally, isolated portions 98 are provided to define the primary tubular passages 84 and the secondary tubular passages 86. The isolated portions 98 are each spaced apart from the wall 26, the backside of the reflector 16, the wall 96, and the wall 38. The isolated portions 98 are each formed into, for example, a hollow profile.
The length of the secondary tubular passage 86 may be set to λ/2 (a half wavelength) relative to the wavelength λ of the acoustic wave frequency of the sound to be absorbed. Because this results in the maxim sound absorption coefficient when the acoustic waves 92 and 94 interfere with each other and cancel each other out at the point 88 after the acoustic wave 92 passes through the primary tubular passage 84 alone, while the acoustic wave 94 rejoins the primary tubular passage 84 via the secondary tubular passage 86.
Other portions of the vehicle sound absorption structure 50 are the same as those according to the first embodiment. Therefore, in the drawings, like numerals are used to represent like elements, and the description of the like elements is not repeated. In addition, the fifth embodiment of the invention may be combined with at least one of the first, the second, and the third embodiments of the invention.
The vehicle sound absorption structure 50 according to the fifth embodiment of the invention has the aforementioned configuration, and the effect of vehicle sound absorption structure 50 will be described below. As illustrated in
It should be understood that the structures of the primary tubular passage 84 and the secondary tubular passage 86 are not limited to the illustrated examples.
[Sixth Embodiment] As illustrated in
It should be understood that the walls 26 and 96 may be angled downwardly to the front side of the vehicle. The walls 26 and 96 are an example of the lower walls. The wall 96 is continuously formed with the divider 14. These angled walls 26 and 96 make it difficult for the water to remain in the cells 12. In the case the communication holes 100 are formed through the lower walls, a similar communication hole (not illustrated) may also be formed through an upper wall (for example, the divider 14). The reason for this is that it is considered relatively easy to form the communication holes through the individual walls.
The arrangement direction of the vehicle sound absorption structure 60 may be varied such that, for example, the openings 24 can be positioned on the upper side of the vehicle, while the reflectors 16 and 18 can be positioned on the lower side of the vehicle. In this case, the communication holes 100 may be formed through the reflectors 16 and 18.
Other portions of the vehicle sound absorption structure 60 are the same as those according to the first embodiment. Therefore, in the drawings, like numerals are used to represent like elements, and the description of the like elements is not repeated. In addition, the sixth embodiment of the invention may be combined with at least one of the first, the second, the third, the fourth, and the fifth embodiments of the invention.
The vehicle sound absorption structure 60 according to the sixth embodiment of the invention has the aforementioned configuration, and the effect of vehicle sound absorption structure 60 will be described below. As illustrated in
When S1 is a cross-sectional area of a smaller-diameter portion 104 that corresponds to the communication hole 100, S2 is a cross-sectional area of a larger-diameter portion 106 that corresponds to the cavity 102, and LS is a length of the larger diameter portion 106, transmission loss TL is expressed as the following equation 1, where: m=S2/S1, f is frequency and c is velocity of sound.
The water in the cells 12 can be drained through the communication holes 100. Specifically, in the case the water (not illustrated) enters the cells 12, when the vehicle is accelerating, an inertial force causes the water to flow toward the rear side of the vehicle. Thus, the water drops through the communication holes 100 to the lower cells 12 sequentially. This allows the water in the cells 12 to be efficiently discharged out of the cells 12. This prevents the water from remaining in the cells 12, and thus prevents a decrease in sound absorption performance due to freezing of the water, thereby maintains the sound absorption performance. It should be understood that when the vehicle is decelerating, the water is discharged from the openings 24 of the cells 12. In addition, the walls 26 and 96 may be angled downwardly to the front side of the vehicle to make it difficult for the water to remain in the cells 12. The walls 26 and 96 are an example of the lower walls. The wall 96 is continuously formed with the divider 14.
(Other Embodiment) As illustrated in
The fender protector 28 is a member designed to shield the gap 48 between the vehicle body framework 46 and the rear end 36A of the front fender panel 36. The rear end 36A is positioned on an inner side of the vehicle. The fender protector 28 is secured to the front fender panel 36 at its rear end 36A and to the vehicle body framework 46 on its forward side of the vehicle, using, for example, an adhesive 54.
The vehicle sound absorption structure 10 is provided on the front surface 28A of the fender protector 28 such that the plural cells 12 are arranged in parallel in the vertical direction with their respective openings 24 facing toward the front side of the vehicle. This allows the sound absorption effect to be produced in a wide region, thus to efficiently absorb noise from the front tyre 44 at low cost.
(Further Other Embodiment) illustrated Illustrated as a further modification of the vehicle sound absorption structure 10 in
According to the further modification, the front surface 28A of the fender protector 28 is utilised as the reflector 18. This enables reductions in material costs of and in weight of the vehicle sound absorption structure 10, compared to the case when the reflector 18 is continuously formed with the wall 26 of the cell 12. As illustrated in
While the invention has been described with reference to example embodiments thereof, it is to be understood that the invention is not limited to the described embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the disclosed invention are shown in various example combinations and configurations, other combinations and configurations, including more, less or only a single element, are also within the scope of the appended claims.
Claims
1. A vehicle sound absorption structure comprising:
- a recessed cell that has an opening on one end thereof;
- a divider that is provided within the cell and that divides an acoustic wave entering the cell from through the opening into two acoustic waves;
- reflectors provided adjacent to the divider that reflect one of the two acoustic waves divided at the divider and reflect the other acoustic wave respectively toward the opening, and that generate a phase difference between the one acoustic wave and the other acoustic wave; and
- an interfering portion that is provided within the cell and that causes the one acoustic wave and the other acoustic wave, which have been respectively reflected at the reflectors, to interfere with each other; and
- a cover member that covers the opening and which opening, wherein the cover member has a slit provided on an extension of that is aligned with the divider.
2. The vehicle sound absorption structure according to claim 1, wherein:
- the divider has an end on a side of that faces the opening and positioned more inward in the cell than the opening, while being positioned closer to the opening than one of the reflectors, the one of the reflectors being positioned closer to the opening than the other reflector; and
- the interfering portion is positioned between the end and the opening.
3. The vehicle sound absorption structure according to claim 2, wherein the slit extends in a direction along the end of the divider.
4. The A vehicle sound absorption structure according to claim 1, comprising:
- a recessed cell that has an opening on one end thereof;
- a divider that is provided within the cell and that divides an acoustic wave entering the cell through the opening into two acoustic waves;
- reflectors provided adjacent to the divider that reflect one of the two acoustic waves divided at the divider and reflect the other acoustic wave respectively toward the opening, and that generate a phase difference between the one acoustic wave and the other acoustic wave;
- an interfering portion that is provided within the cell and that causes the one acoustic wave and the other acoustic wave, which have been respectively reflected at the reflectors, to interfere with each other;
- a cover member that covers the opening,
- wherein the cell is the vehicle sound absorption structure further comprises a plurality of cells, adjacent cells being partitioned by a wall that includes a base part and the an other part, the base part being thinner than the other part.
5. The vehicle sound absorption structure according to claim 1, wherein:
- the vehicle sound absorption structure also serves as a fender protector that shields a gap between a vehicle body framework and a rear end of a front fender panel, the rear end being positioned inner side of the of a vehicle; and
- the opening is formed toward the a front side of the vehicle.
6. The vehicle sound absorption structure according to claim 1, wherein the vehicle sound absorption structure is provided on a front surface of a fender protector that shields a gap between a vehicle body framework and a rear end of a front fender panel, a of a vehicle, the front surface facing toward the a front side of the vehicle, the rear end being positioned inner side of the vehicle.
7. The vehicle sound absorption structure according to claim 6 1, wherein:
- the vehicle sound absorption structure is formed in combination with mounted on the fender protector; and
- a front surface of the fender protector is utilised as one of the reflectors, the front surface facing toward the front side of the vehicle reflectors.
8. The vehicle sound absorption structure according to claim 1, wherein:
- the vehicle sound absorption structure also serves as a fender liner that is formed on an inside of the front fender panel to cover a front tyre; and
- the opening is formed toward the front side of the vehicle.
9. The A vehicle sound absorption structure according to claim 1, comprising: wherein:
- a recessed cell that has an opening on one end thereof;
- a divider that is provided within the cell and that divides an acoustic wave entering the cell through the opening into two acoustic waves;
- reflectors provided adjacent to the divider that reflect one of the two acoustic waves divided at the divider and reflect the other acoustic wave respectively toward the opening, and that generate a phase difference between the one acoustic wave and the other acoustic wave;
- an interfering portion that is provided within the cell and that causes the one acoustic wave and the other acoustic wave, which have been respectively reflected at the reflectors, to interfere with each other;
- a cover member that covers the opening,
- a plurality of the cells are arranged in parallel in a vertical direction with the an opening of each of the cells facing toward the a front side of the a vehicle; and
- communication holes communicating with a lower adjacent one of the cells are formed on lower walls of the cells.
10. The vehicle sound absorption structure according to claim 9, wherein the lower walls are angled downwardly to the front side of the vehicle.
11. The vehicle sound absorption structure according to claim 9, wherein the communication holes are provided on the lower walls at respective ends of the lower walls on the a rear side of the vehicle.
12. The vehicle sound absorption structure according to claim 1, further comprising a plurality of cells such that adjacent cells are partitioned by plural walls, a Helmholtz resonator that is provided adjacent to the cells and that has a neck and a cavity, the neck being open in the same direction as the opening, wherein the neck is defines an opening of the Helmholtz resonator, the opening of the Helmholtz resonator being defined by the walls.
13. The vehicle sound absorption structure according to claim 12, wherein a volume of the cavity, a diameter of the neck or a length of the neck is varied in order to adjust sound-absorption characteristics of the Helmholtz resonator.
14. The vehicle sound absorption structure according to claim 13 12, wherein the cavity is formed into a trapezium or trapezoid shape.
15. The vehicle sound absorption structure according to claim 1, further comprising:
- a primary tubular passage that is provided adjacent to the cells cell and is open toward the same direction as the opening; and
- a secondary tubular passage that is branched from the primary tubular passage at a midsection of the primary tubular passage and that rejoins the primary tubular passage at a point where the primary tubular passage and the secondary tubular passage join together,
- wherein the primary tubular passage and the secondary tubular passage respectively have predetermined lengths such that an acoustic wave passing through the primary tubular passage alone and another acoustic wave rejoining the primary tubular passage via the secondary tubular passage have a phase difference therebetween at the point where the primary tubular passage and the secondary tubular passage join together.
16. A front fender structure of a vehicle comprising:
- a front fender panel;
- a fender protector that shields a gap between a vehicle body framework and a rear end of the front fender panel, the rear end being positioned inner side of the vehicle; and
- a vehicle sound absorption structure according to claim 1,
- wherein the vehicle sound absorption structure being mounted onto a surface of the fender protector with the opening facing toward the a front side of the vehicle, the surface facing toward the front side of the vehicle, wherein a plurality of the cells are arranged in parallel in a vertical direction, and the cells each have lower walls through which communication holes are formed, the communication holes communicating with a lower adjacent one of the cells.
17. The vehicle sound absorption structure according to claim 1, wherein the reflectors comprise a first reflector and a second reflector, the first reflector is disposed at a different depth with respect to the opening than the second reflector.
18. The vehicle sound absorption structure according to claim 1, wherein the slit extends in a same direction as the divider.
19. A front fender structure of a vehicle comprising:
- a front fender panel;
- a fender protector that shields a gap between a vehicle body framework and a rear end of the front fender panel; and
- a vehicle sound absorption structure comprising: a recessed cell that has an opening on one end thereof; a divider that is provided within the cell and that divides an acoustic wave entering the cell through the opening into two acoustic waves; reflectors provided adjacent to the divider that reflect one of the two acoustic waves divided at the divider and reflect the other acoustic wave respectively toward the opening, and that generate a phase difference between the one acoustic wave and the other acoustic wave; an interfering portion that is provided within the cell and that causes the one acoustic wave and the other acoustic wave, which have been respectively reflected at the reflectors, to interfere with each other; and a cover member that covers the opening,
- wherein: the vehicle sound absorption structure being mounted onto a surface of the fender protector with the opening facing toward a front side of the vehicle, the surface facing toward the front side of the vehicle, and a plurality of cells are arranged in parallel in a vertical direction, and the cells each have lower walls through which communication holes are formed, the communication holes communicating with a lower adjacent one of the cells.
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Type: Grant
Filed: Aug 11, 2016
Date of Patent: Jun 25, 2019
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA (Toyota)
Inventor: Toyoka Ide (Nisshin)
Primary Examiner: Peter C English
Application Number: 15/234,401
International Classification: B60R 13/08 (20060101); G10K 11/175 (20060101);