Vehicle sound absorbing device

Abstract

To provide a vehicle sound absorption structure which enables reduction of the cubic volume occupied in a space between a vehicle interior and a vehicle exterior.SOLUTION: A vehicle sound absorption device 10 is disposed in a ventilation space 50S of a vehicle including a communication port 53, which allows communication between a ventilation space 50S located between a rear bumper 51 and a rear side member 52 and a vehicle room, in a rear side member 52. The vehicle sound absorption device includes: a shield plate 10M which is connected to the rear bumper 51 and the rear side member 52 and partitions the ventilation space 50S into a first space 50S1, in which the communication port 53 is disposed, and a second space 50S2 other than the first space; and a sound absorption structure 11 which protrudes from a first surface 10M1 facing the first space 50S1 to the first space 50S1 in the shield plate 10M.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a sound absorbing device for a vehicle that is disposed between the exterior and interior of the vehicle. [Background technology]

[0002] The vehicle interior separating the vehicle compartment has a ventilation opening penetrating the vehicle interior. The ventilation opening is equipped with a ventilator. When the air pressure in the vehicle compartment is not changing, the ventilator closes the ventilator through-hole. When the air pressure in the vehicle compartment increases, the ventilator releases air from the vehicle compartment to the outside through the space between the vehicle interior and the vehicle exterior.

[0003] Sound that penetrates the space between the vehicle exterior and the vehicle interior diffuses between the vehicle exterior and the vehicle interior, and then penetrates into the vehicle cabin through the ventilation opening. The vehicle sound-absorbing device is disposed in the space between the vehicle exterior and the vehicle interior. The vehicle sound-absorbing device suppresses the diffusion of sound before the sound that diffuses in the space between the vehicle exterior and the vehicle interior reaches the vehicle cabin.

[0004] An example of a sound-absorbing device is placed between the vehicle interior and exterior along the periphery of the ventilation opening. The sound-absorbing device is made of sound-absorbing material such as urethane pads or felt, or a composite material in which a fiber material or a resin material is laminated onto a sound-absorbing material. The sound-absorbing device prevents sound that has entered the space between the vehicle exterior and interior from diffusing to the periphery of the ventilation opening (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-16809 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, a sound absorbing device disposed along the periphery of the ventilation opening occupies the space required for arranging the sound absorbing material over almost the entire periphery of the ventilation opening. Reducing the space occupied by the sound absorbing device can improve the breathability of the space between the vehicle interior and the vehicle exterior around the periphery of the ventilation opening and can expand the vehicle cabin. [Means for solving the problem]

[0007] A vehicle sound absorbing device for solving the above problem is a vehicle sound absorbing device that is arranged in an air ventilation space, which is the space between the vehicle exterior and the vehicle interior, and has a communication opening in the vehicle interior that connects the space to the vehicle compartment, and that includes a shielding plate that is connected to the vehicle exterior and the vehicle interior to separate the air ventilation space into a first space in which the communication opening is located and a second space other than the first space, and a sound absorbing structure that protrudes toward the first space from a first surface of the shielding plate that faces the first space.

[0008] In the vehicle sound absorbing device described above, the shielding plate separates the ventilation space into a first space and a second space. In this case, the vehicle sound absorbing device forms a resonant system consisting of a spring and a mass. The sound absorbing structure protruding from the shielding plate toward the first space functions as the mass of the resonant system. The rigidity of the shielding plate, the rigidity of the sound absorbing structure, and the elasticity of the air in the second space function as the spring of the resonant system.

[0009] When sound of the same frequency as the resonant frequency strikes the sound-absorbing device in the first space, the device vibrates and the vibration energy is converted into heat energy through friction loss in the sound-absorbing structure and the sound-absorbing device of the vehicle absorbs the sound, while the sound-absorbing structure increases the mass of the resonant system, suppressing fluctuations in the resonant frequency.

[0010] As a result, a sound-absorbing device placed on the second space side of the communication opening can achieve sound absorption effects, but the volume occupied by the sound-absorbing device around the communication opening is reduced compared to a sound-absorbing device placed along the periphery of the communication opening.

[0011] In the above-mentioned vehicle sound absorbing device, the shielding plate may have a shape extending in the longitudinal direction of the vehicle, the sound absorbing structure may include a plurality of sound absorbing plates arranged in a direction intersecting the longitudinal direction, and the sound absorbing plates may have a wavy shape that is continuous in the longitudinal direction when viewed from a viewpoint opposite the first surface.

[0012] According to the above-mentioned vehicle sound absorbing device, the sound absorbing structure is composed of multiple sound absorbing panels, so it is possible to change the mass of the resonant system by changing the number of sound absorbing panels. Furthermore, because the sound absorbing panels have a wave shape extending in the longitudinal direction of the insulating panel, it is also possible to change the rigidity of the sound absorbing panels over a wide range. Therefore, the vehicle sound absorbing device can easily adjust its resonant frequency to the frequency of the sound reaching the vehicle cabin, and therefore it is easy to achieve suitable sound absorption.

[0013] In the above-mentioned vehicle sound absorbing device, one of the vehicle interior and the vehicle exterior may be a first exterior, and the vehicle interior and the vehicle exterior other than the first exterior may be a second exterior, and the shielding plate may be fixed to the first exterior so as to be swingable relative to the second exterior.

[0014] In the above-mentioned vehicle sound absorbing device, one of the vehicle interior and the vehicle exterior is a first exterior, and the vehicle interior and the vehicle exterior other than the first exterior is a second exterior, and the shielding plate may be fixed to the first exterior via an adhesive layer and supported on the second exterior via an elastic body.

[0015] According to each of the above configurations, the shielding plate can swing between the vehicle interior and the vehicle exterior, which also makes it possible to reduce the load on the shielding plate caused by vibrations of the vehicle interior and vehicle exterior. In the above-mentioned vehicle sound absorbing device, the shielding plate may include a reinforcing rib protruding from the first surface toward the first space, the reinforcing rib having a linear shape extending in a direction intersecting the fore-and-aft direction when viewed from a viewpoint opposite the first surface, and the plurality of sound absorbing plates may include sound absorbing plates connected to the reinforcing rib.

[0016] In the above-mentioned vehicle sound-absorbing device, the shielding plate may include two reinforcing ribs protruding from the first surface toward the first space, the reinforcing ribs having a linear shape extending in a direction intersecting the longitudinal direction when viewed from a viewpoint opposite the first surface and aligned in the longitudinal direction, and the plurality of sound-absorbing plates may include sound-absorbing plates arranged between the two reinforcing ribs and connected to the two reinforcing ribs.

[0017] According to each of the above configurations, the shielding plate and the sound absorbing plate are reinforced by the reinforcing ribs, so that the durability of the sound absorbing device is increased and the sound absorbing effect of the sound absorbing device can be obtained for a long period of time. In the vehicle sound absorbing device, the shielding plate and the sound absorbing structure may be integrated. In this sound absorbing device, since the shielding plate and the sound absorbing structure are integrated, an increase in the number of components of the sound absorbing device can be suppressed, and the cost required for absorbing sound in the ventilation space can also be suppressed. [Effects of the Invention]

[0018] According to the above-described vehicle sound absorbing device, the volume occupied by the sound absorbing device around the communication opening is reduced while still achieving a sound absorbing effect in the ventilation space. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view showing a sound absorbing device for a vehicle together with the vehicle exterior and vehicle interior. [Figure 2] FIG. 2 is a perspective view of the vehicle sound absorbing device as seen from above. [Figure 3] FIG. 3 is an exploded perspective view showing a sound absorbing device for a vehicle. [Figure 4] FIG. 4 is a perspective view of the vehicle sound absorbing device as seen from below. [Figure 5] FIG. 5 is a side view showing a sound absorbing device for a vehicle. [Figure 6] FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. [Figure 7] 7 is a cross-sectional view taken along line 7-7 in FIG. [Figure 8]FIG. 8 is a perspective view showing an example of a sound-absorbing device for a vehicle used in the calculation of sound transmission loss. [Figure 9] FIG. 9 is a graph showing the results of the sound transmission loss calculation. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of a vehicle sound absorbing device will be described below. First, the peripheral structure of the sound absorbing device will be described with reference to Fig. 1. Next, the vehicle sound absorbing device will be described with reference to Figs. 3 to 7. Then, the operation of the vehicle sound absorbing device will be described with reference to Figs. 8 and 9.

[0021] [Surrounding structure] As shown in Fig. 1, a rear bumper 51, which is an example of a vehicle exterior, and a rear side member 52, which is an example of a vehicle interior, separate a ventilation space 50S. The upper end of the ventilation space 50S in Fig. 1 is separated by a rear combination lamp and the like. The lower end of the ventilation space 50S in Fig. 1 is open to the outside of the vehicle.

[0022] The rear side member 52 has a communication opening 53 penetrating the rear side member 52. The communication opening 53 connects the ventilation space 50S with the vehicle cabin. The rear side member 52 has a vent duct 54 attached to the communication opening 53. When the air pressure in the vehicle cabin does not change, the vent duct 54 closes the communication opening 53. When the air pressure in the vehicle cabin increases, the vent duct 54 operates in the direction of the arrow, and air in the vehicle cabin is released to the outside of the vehicle cabin through the ventilation space 50S.

[0023] The sound absorbing device 10 of the vehicle is disposed in the ventilation space 50S. The sound absorbing device 10 is a one-piece resin molded body. The sound absorbing device 10 is made of, for example, polypropylene, ABS, or polycarbonate. The sound absorbing device 10 includes a shielding plate 10M and a sound absorbing structure 11.

[0024] The shielding plate 10M is fixed to the rear bumper 51 via an adhesive layer 61. The shielding plate 10M is supported by the rear side member 52 via an elastic body 62. The shielding plate 10M separates the ventilation space 50S into a first space 50S1 in which the vent duct 54 is disposed and a second space 50S2 other than the first space 50S1.

[0025] The first space 50S1 communicates with the vehicle interior via the vent duct 54. The first space 50S1 communicates with the exterior of the vehicle. Road noise and other abnormal noises generated below the vehicle enter the first space 50S1 from below the vehicle. The second space 50S2 is separated by a rear combination lamp and the like.

[0026] [Sound absorbing device 10] 2, the shielding plate 10M includes a plate body 12, an outer peripheral wall 13, and a plurality of inner peripheral walls 14. The shielding plate 10M includes a front end 10F and a rear end 10B. The shielding plate 10M has an elliptical plate shape that extends in the longitudinal direction of the vehicle from the front end 10F to the rear end 10B.

[0027] The outer peripheral wall 13 is integral with the edge of the periphery of the shielding plate 10M that faces the rear bumper 51. The outer peripheral wall 13 has a strip shape that extends along the edge of the shielding plate 10M. The outer peripheral wall 13 protrudes above and below the vehicle from the edge of the shielding plate 10M.

[0028] The inner peripheral wall 14 is integral with the edge of the periphery of the shielding plate 10M that faces the rear side member 52. The inner peripheral wall 14 has a strip shape that extends along the edge of the shielding plate 10M. The inner peripheral walls 14 are lined up at intervals along the edge of the shielding plate 10M. The inner peripheral walls 14 protrude above and below the vehicle from the edge of the shielding plate 10M.

[0029] The plate main body 12 has a shape that curves upward from the front end 10F toward the rear end 10B (see FIGS. 3 and 5). The plate main body 12 has a first surface 10M1 (see FIG. 4) and a second surface 10M2. The first surface 10M1 faces the first space 50S1. The second surface 10M2 faces the second space 50S2. The plate main body 12 has a plurality of ventilation holes 12H that penetrate from the first surface 10M1 to the second surface 10M2.

[0030] The second surface 10M2 has two second reinforcing ribs 12R. The second reinforcing ribs 12R protrude upward from the second surface 10M2. The amount by which the second reinforcing ribs 12R protrude from the second surface 10M2 is approximately equal to the amount by which the outer peripheral wall 13 protrudes from the second surface 10M2 and the amount by which the inner peripheral wall 14 protrudes from the second surface 10M2. When viewed from a perspective facing the second surface 10M2, the second reinforcing ribs 12R have a linear shape extending in the left-right direction intersecting the front-to-rear direction. One second reinforcing rib 12R is located approximately in the center of the second surface 10M2 in the front-to-rear direction. The other second reinforcing rib 12R is located between one second reinforcing rib 12R and the front end 10F. The second reinforcing rib 12R is connected to the outer peripheral wall 13 and the inner peripheral wall 14.

[0031] As shown in Figure 3, the two adhesive layers 61 are bonded to the outer surface 13S of the outer peripheral wall 13. The outer surface 13S of the outer peripheral wall 13 is fixed to the rear bumper 51 via the adhesive layers 61. The elastic body 62 has a shape that follows the shape of the inner peripheral wall 14. The elastic body 62 is sandwiched between the inner peripheral wall 14 and the rear side member 52. The adhesive layers 61 are, for example, double-sided tape. The elastic body 62 is made of, for example, ethylene propylene rubber or a urethane pad.

[0032] The sound absorbing device 10 is supported so as to be able to swing relative to the rear side member 52, with the outer peripheral wall 13 serving as a fixed end. Because the sound absorbing device 10 can swing between the rear bumper 51 and the rear side member 52, the load on the sound absorbing device 10 due to vibrations of the rear bumper 51 and the rear side member 52 is reduced.

[0033] [Sound-absorbing structure 11] 4, the shielding plate 10M has two first reinforcing ribs 12R1 and a sound absorbing structure 11 on a first surface 10M1. The first reinforcing ribs 12R1 are arranged on the first surface 10M1 so as to sandwich the center in the front-to-rear direction of the plate main body portion 12. The two first reinforcing ribs 12R1 increase the rigidity of the plate main body portion 12 in areas other than the center in the front-to-rear direction of the plate main body portion 12.

[0034] The sound absorbing structure 11 is arranged on the first surface 10M1 so that the sound absorbing structure 11 includes the center of the first surface 10M1 in the front-to-rear direction. The sound absorbing structure 11 is arranged on the first surface 10M1 so that the sound absorbing structure 11 includes the portion of the first surface 10M1 that is widest in the left-to-right direction. The sound absorbing structure 11 is arranged in a portion of the board main body 12 that is not increased in rigidity by the first reinforcing rib 12R1 and that is wide in the left-to-right direction. The sound absorbing structure 11 is arranged in a portion of the board main body 12 that is prone to vibration.

[0035] The first reinforcing rib 12R1 protrudes downward from the first surface 10M1. The amount by which the first reinforcing rib 12R1 protrudes from the first surface 10M1 is approximately equal to the amount by which the outer peripheral wall 13 protrudes from the first surface 10M1 near the outer peripheral wall 13. The amount by which the first reinforcing rib 12R1 protrudes from the first surface 10M1 is approximately equal to the amount by which the inner peripheral wall 14 protrudes from the first surface 10M1 near the inner peripheral wall 14. The amount by which the first reinforcing rib 12R1 protrudes from the first surface 10M1 gradually increases from the outer peripheral wall 13 toward the inner peripheral wall 14.

[0036] The first reinforcing ribs 12R1 have a linear shape extending in the left-right direction intersecting the front-rear direction when viewed from a viewpoint facing the first surface 10M1. One first reinforcing rib 12R1 is located closer to the front end 10F than the center of the first surface 10M1 in the front-rear direction. The other first reinforcing rib 12R1 is located closer to the rear end 10B than the center of the first surface 10M1 in the front-rear direction. The first reinforcing ribs 12R1 are connected to the outer peripheral wall 13 and the inner peripheral wall 14.

[0037] 6, the sound-absorbing structure 11 is composed of eight sound-absorbing panels 15. The sound-absorbing panels 15 are arranged in a left-right direction that intersects with the front-rear direction. The sound-absorbing panels 15 are arranged across almost the entire first surface 10M1 in the left-right direction.

[0038] The sound-absorbing panel 15 extends from one first reinforcing rib 12R1 to another first reinforcing rib 12R1 (see FIG. 4). The sound-absorbing panel 15 has a continuous wave shape in the front-to-rear direction when viewed from a viewpoint facing the first surface 10M1. The sound-absorbing structure 11 includes a sound-absorbing panel 15 connected to two first reinforcing ribs 12R1. The sound-absorbing structure 11 includes a sound-absorbing panel 15 whose both ends in the front-to-rear direction are connected to the inner peripheral wall 14, and a sound-absorbing panel 15 whose both ends in the front-to-rear direction are connected to the outer peripheral wall 13.

[0039] In the left-right direction that intersects with the front-rear direction, adjacent sound-absorbing panels 15 are parallel to each other. The period of the wave shape of the sound-absorbing panels 15 in the front-rear direction is approximately equal to the distance between adjacent sound-absorbing panels 15 in the left-right direction. One mountain-shaped structure among the wave shapes of the sound-absorbing panels 15 is periodically repeated in the front-rear direction and the left-right direction over almost the entire area sandwiched between the two first reinforcing ribs 12R1.

[0040] 7, the sound-absorbing panel 15 protrudes downward from the first surface 10M1. The amount by which the sound-absorbing panel 15 protrudes from the first surface 10M1 is approximately equal to the amount by which the outer peripheral wall 13 protrudes from the first surface 10M1 in the vicinity of the outer peripheral wall 13. The amount by which the sound-absorbing panel 15 protrudes from the first surface 10M1 is approximately equal to the amount by which the inner peripheral wall 14 protrudes from the first surface 10M1 in the vicinity of the inner peripheral wall 14. The amount by which the sound-absorbing panel 15 protrudes from the first surface 10M1 gradually increases from the outer peripheral wall 13 toward the inner peripheral wall 14, similar to the first reinforcing rib 12R1.

[0041] The thickness of the sound-absorbing board 15 in the left-right direction gradually decreases from the first surface 10M1 toward the tip of the sound-absorbing board 15. The thickness of the sound-absorbing board 15 in the left-right direction gradually decreases, for example, from 1.2 mm to 0.8 mm. The thickness of the sound-absorbing board 15 in the left-right direction is equal to or less than the thickness of the board main body 12. The tapered shape of the sound-absorbing board 15 makes it easier to remove the mold for forming the sound-absorbing structure 11 from the base end of the sound-absorbing board 15 toward the tip.

[0042] In this way, the shielding plate 10M separates the ventilation space 50S into the first space 50S1 and the second space 50S2. In this configuration, the vehicle sound-absorbing device 10 forms a resonant system consisting of a spring and a mass. The sound-absorbing structure 11 protruding from the shielding plate 10M toward the first space 50S1 functions as the mass of the resonant system. The rigidity of the shielding plate 10M, the rigidity of the sound-absorbing structure 11, and the elasticity of the air in the second space 50S2 function as the spring of the resonant system.

[0043] When sound of the same frequency as the resonant frequency strikes the sound-absorbing device 10 in the first space 50S1, the sound-absorbing device 10 vibrates, and the vibrational energy is converted to thermal energy through frictional losses in the shielding plate 10M and the sound-absorbing structure 11. This allows the sound-absorbing device 10 to absorb sound from the vehicle, while the sound-absorbing structure 11 increases the mass of the resonant system and suppresses fluctuations in the resonant frequency. Furthermore, collision between abnormal noise, such as road noise from below the vehicle, and abnormal noise reflected by the shielding plate 10M cancels out the abnormal noise, reducing the amount of abnormal noise transmitted through the communication opening 53 into the vehicle cabin. As a result, a sound-absorbing device 10 positioned on the second space 50S2 side of the communication opening 53 provides a sound-absorbing effect while reducing the volume occupied by the sound-absorbing device 10 around the communication opening 53, compared to a sound-absorbing device 10 positioned along the periphery of the communication opening 53.

[0044] [Sound transmission loss] Next, the operation of the sound absorbing device 10 will be described with reference to Figures 8 and 9. Figure 8 shows a perspective view of the structure of a sound absorbing device 70. Figure 9 shows, as Test Example 1, the calculation results of the sound transmission loss of the sound absorbing device 10 described with reference to Figures 2 to 7. Figure 9 also shows, as Test Example 2, the calculation results of the sound transmission loss of the sound absorbing device 70 shown in Figure 8. Note that the sound absorbing device 70 used in the sound transmission loss calculations has a different structure from the sound absorbing device 10 in terms of the sound absorbing panel 15, but has the same other structure as the sound absorbing device 10. Below, we will mainly explain the configuration of the sound absorbing device 70 that differs from the sound absorbing device 10, and will omit redundant explanations of the configuration that is common to the sound absorbing device 10.

[0045] As shown in Figure 8, the sound absorbing device 70 includes five sound absorbing panels 75. The sound absorbing panels 75 extend from the outer peripheral wall 13 to the inner peripheral wall 14. The sound absorbing panels 75 have a linear shape that continues in the left-right direction when viewed from a viewpoint facing the first surface 10M1. The five sound absorbing panels 75 are equally spaced in the front-rear direction between the two first reinforcing ribs 12R1. The sound absorbing panels 75 that are adjacent to each other in the front-rear direction are parallel to each other.

[0046] The sound-absorbing panel 75 protrudes downward from the first surface 10M1. The amount by which the sound-absorbing panel 75 protrudes from the first surface 10M1 is approximately equal to the amount by which the outer peripheral wall 13 protrudes from the first surface 10M1 in the vicinity of the outer peripheral wall 13. The amount by which the sound-absorbing panel 75 protrudes from the first surface 10M1 is approximately equal to the amount by which the inner peripheral wall 14 protrudes from the first surface 10M1 in the vicinity of the inner peripheral wall 14. The amount by which the sound-absorbing panel 75 protrudes from the first surface 10M1 gradually increases from the outer peripheral wall 13 toward the inner peripheral wall 14, similar to the first reinforcing rib 12R1.

[0047] The thickness of the sound-absorbing board 75 in the front-to-rear direction gradually decreases from the first surface 10M1 toward the tip of the sound-absorbing board 75. The thickness of the sound-absorbing board 75 in the front-to-rear direction is equal to the thickness of the sound-absorbing board 15 in the left-to-right direction and is equal to or less than the thickness of the board main body 12.

[0048] FIG. 9 shows the calculation results of sound transmission loss at each frequency from 200 Hz to 4000 Hz obtained using acoustic analysis software. The sound transmission loss of Test Example 1 was obtained from a structural mesh conforming to the structure of sound absorbing device 10 and an elliptical cylindrical acoustic mesh extending in the vertical direction surrounding sound absorbing device 10. The sound transmission loss of Test Example 2 was obtained from a structural mesh conforming to the structure of sound absorbing device 70 and the same elliptical cylindrical acoustic mesh as Test Example 1. In this case, an acoustic input surface mesh was set in the first space 50S1 of sound absorbing device 10, and an acoustic radiating surface mesh was set in the second space 50S2 of sound absorbing device 10. The sound transmission loss of Test Example 1 was then calculated from the input power of the acoustic input surface mesh and the radiation power of the acoustic radiating surface mesh. In addition, an acoustic input surface mesh was set in the first space 50S1 of the sound absorbing device 70, and an acoustic radiating surface mesh was set in the second space 50S2 of the sound absorbing device 70, and the ratio between the input power of the acoustic input surface mesh and the radiation power of the acoustic radiating surface mesh was calculated.

[0049] As shown in Figure 9, the sound transmission loss of Test Example 1 has one peak near 800 Hz, indicating the highest sound transmission loss. The sound transmission loss of Test Example 1 has a broad peak near 1600 Hz, indicating a lower sound transmission loss than near 800 Hz. On the other hand, the sound transmission loss of Test Example 2 has no peak near 800 Hz, and only a broad peak near 1600 Hz. This confirms that the sound absorbing devices 10 and 70 can achieve a sound absorbing effect. It is also confirmed that the sound absorbing structure 11 composed of the sound absorbing panel 15 exhibits a higher sound absorbing effect than the sound absorbing panel 75.

[0050] As described above, according to the above embodiment, the following effects can be obtained. (1) The sound-absorbing structure 11 protruding from the shielding plate 10M into the first space 50S1 provides a sound-absorbing effect, but the volume occupied by the sound-absorbing devices 10, 70 around the communication opening 53 is reduced compared to the sound-absorbing device 10 arranged along the peripheral portion of the communication opening 53.

[0051] (2) Because the sound-absorbing structure 11 is composed of multiple sound-absorbing panels 15, 75, it is also possible to change the mass of the resonant system by changing the number of sound-absorbing panels 15, 75. This makes it easier for the vehicle sound-absorbing device 10, 70 to adjust its resonant frequency to the frequency of the sound that reaches the vehicle cabin, thereby making it easier to achieve suitable sound absorption.

[0052] (3) When the sound-absorbing panel 15 has a corrugated shape extending in the longitudinal direction of the shielding plate 10M, the sound-absorbing effect is enhanced compared to the sound-absorbing panel 75 that extends in the left-right direction. It also becomes possible to change the rigidity of the sound-absorbing panel 15 over a wide range. Therefore, the resonant frequency of the sound-absorbing device 10 for a vehicle can be easily adjusted to the frequency of the sound that reaches the vehicle cabin, which in turn makes it easier to achieve suitable sound absorption.

[0053] (4) If the shielding plate 10M can swing between the rear bumper 51 and the rear side member 52, the load on the shielding plate 10M caused by the vibration of the rear bumper 51 and the rear side member 52 can be reduced.

[0054] (5) When the shielding plate 10M and the sound absorbing plate 15 are reinforced by the first reinforcing rib 12R1, the durability of the sound absorbing device 10 is increased and the sound absorbing effect of the sound absorbing device 10 can be maintained for a long period of time.

[0055] The above embodiment can be modified as follows. [Sound absorbing board 15,75] The first reinforcing rib 12R1 may be omitted from the sound absorbing device 10, 70. In this case, the sound absorbing plate 15, 75 may be supported only by the first surface 10M1.

[0056] The sound absorbing plates 15, 75 may be disposed on the first surface 10M1 so as to be spaced apart from at least one of the two first reinforcing ribs 12R1. The sound-absorbing board 15, 75 may be disposed on the first surface 10M1 so that the sound-absorbing board 15, 75 crosses the first reinforcing rib 12R1. In this case, the sound-absorbing board 15, 75 may be disposed so that at least one of both ends of the sound-absorbing board 15, 75 in the front-rear direction is spaced apart from the first reinforcing rib 12R1.

[0057] The multiple sound-absorbing panels 15, 75 may include sound-absorbing panels 15, 75 having different thicknesses. The multiple sound-absorbing panels 15, 75 may include sound-absorbing panels 15, 75 that protrude from the first surface 10M1 by different amounts. The multiple sound-absorbing panels 15, 75 may include sound-absorbing panels 15, 75 having different lengths in the extension direction of the sound-absorbing panels 15, 75. In other words, sound-absorbing elements such as the sound-absorbing panels 15, 75 may be different from one another within the sound-absorbing structure 11.

[0058] [Sound-absorbing structure 11] The sound absorbing structure 11 may have a plate shape that protrudes from the first surface 10M1 into the first space 50S1, and may have a honeycomb shape in which regular polygons are arranged when viewed from a viewpoint opposite the first surface 10M1.

[0059] The sound-absorbing structure 11 may include a cylindrical Helmholtz structure that protrudes from the first surface 10M1 into the first space 50S1. In this case, the sound-absorbing structure 11 may be configured with Helmholtz structures that are spread over the first surface 10M1 when viewed from a viewpoint facing the first surface 10M1, or may include Helmholtz structures that are scattered over the first surface 10M1.

[0060] The sound-absorbing structure 11 may have a cone shape that protrudes from the first surface 10M1 into the first space 50S1. In this case, the sound-absorbing structure 11 may be made up of cones that are spread all over the first surface 10M1, or cones that are scattered across the first surface 10M1, as viewed from a viewpoint opposite the first surface 10M1.

[0061] [Shielding plate 10M] The shielding plate 10M may be supported on the rear bumper 51 via an elastic body 62 instead of the adhesive layer 61. The shielding plate 10M may be fixed to the rear side member 52 via an adhesive layer 61 instead of the elastic body 62. That is, one of the vehicle interior and the vehicle exterior is the first exterior, and the vehicle interior and the vehicle exterior other than the first exterior is the second exterior, and the shielding plate 10M may be connected to the first exterior and the second exterior via an adhesive material or via an elastic member. Alternatively, the shielding plate 10M may be connected to the first exterior via an adhesive material and to the second exterior via an elastic member.

[0062] The shielding plate 10M may be separate from the sound-absorbing structure 11. If the shielding plate 10M and the sound-absorbing structure 11 are separate, it is possible to reduce manufacturing constraints on the structure of the sound-absorbing structure 11 compared to when the shielding plate 10M and the sound-absorbing structure 11 are integrated. On the other hand, if the shielding plate 10M and the sound-absorbing structure 11 are integrated, it is possible to prevent an increase in the number of components of the sound-absorbing device 10 and also to reduce the cost required for absorbing sound in the ventilation space 50S.

[0063] [Ventilation space 50S] The sound absorbing device 10 may be disposed above the communication opening 53 in the ventilation space 50S. The sound absorbing device 10 may be disposed below the communication opening 53 in the ventilation space 50S.

[0064] The upper end of the ventilation space 50S may be separated by a rear combination lamp or the like, or may be connected to the vehicle interior. In this case, the first space 50S1 may be connected only to the outside of the vehicle, and the second space 50S2 may be connected to the vehicle interior. Furthermore, the ventilation space 50S may be any space that connects the vehicle interior to the outside of the vehicle, and the vent duct 54 may be omitted from the rear side member 52.

[0065] The technical ideas derived from the above-described embodiment and modifications are described below. [Appendix 1] A sound absorbing device for a vehicle, the sound absorbing device including a communication port in the vehicle interior that communicates a ventilation space, which is a space between a vehicle exterior and a vehicle interior, with a vehicle compartment, the communication port being provided in the ventilation space, the sound absorbing device being arranged in the ventilation space, a shielding plate that is connected to the vehicle exterior and the vehicle interior to separate the ventilation space into a first space in which the communication port is disposed and a second space other than the first space; a sound absorbing structure protruding from a first surface of the shielding plate facing the first space toward the first space, A sound absorbing device for a vehicle.

[0066] [Appendix 2] the shielding plate has a shape extending in the front-rear direction of the vehicle, the sound-absorbing structure includes a plurality of sound-absorbing plates arranged in a direction intersecting the front-rear direction, the sound-absorbing panel has a wave shape that is continuous in the front-rear direction when viewed from a viewpoint opposite to the first surface, 10. A sound absorbing device for a vehicle as described in appendix 1.

[0067] [Appendix 3] one of the vehicle interior and the vehicle exterior is a first exterior; Among the vehicle interior and the vehicle exterior, the one other than the first exterior is a second exterior, The shielding plate is fixed to the first exterior so as to be swingable relative to the second exterior. 3. A sound-absorbing device for a vehicle as set forth in appendix 1 or 2.

[0068] [Appendix 4] one of the vehicle interior and the vehicle exterior is a first exterior; Among the vehicle interior and the vehicle exterior, the one other than the first exterior is a second exterior, the shielding plate is fixed to the first exterior via an adhesive layer and supported by the second exterior via an elastic body; 4. A sound-absorbing device for a vehicle according to any one of appendices 1 to 3.

[0069] [Appendix 5] the shielding plate includes a reinforcing rib protruding from the first surface toward the first space, the reinforcing rib has a linear shape extending in a direction intersecting the front-rear direction when viewed from a viewpoint opposite the first surface, The plurality of sound-absorbing plates include the sound-absorbing plate connected to the reinforcing rib. 1. A sound absorbing device for a vehicle as described in Appendix 2.

[0070] [Appendix 6] the shielding plate includes two reinforcing ribs protruding from the first surface toward the first space, the reinforcing ribs have a linear shape extending in a direction intersecting the front-rear direction when viewed from a viewpoint opposite the first surface, and are aligned in the front-rear direction; The plurality of sound-absorbing plates include a sound-absorbing plate disposed between the two reinforcing ribs and connected to the two reinforcing ribs. 10. A sound absorbing device for a vehicle as described in appendix 5.

[0071] [Appendix 7] one of the vehicle interior and the vehicle exterior is a first exterior; Among the vehicle interior and the vehicle exterior, the one other than the first exterior is a second exterior, the shielding plate is fixed to the first exterior via an adhesive layer and supported by the second exterior via an elastic body; 10. A sound absorbing device for a vehicle as described in Appendix 6.

[0072] [Appendix 8] A sound absorbing device for a vehicle, the sound absorbing device including a communication port in the vehicle interior that communicates a ventilation space, which is a space between a vehicle exterior and a vehicle interior, with a vehicle compartment, the communication port being provided in the ventilation space, the sound absorbing device being arranged in the ventilation space, a shielding plate that is connected to the vehicle exterior and the vehicle interior to separate the ventilation space into a first space and a second space other than the first space; a sound absorbing structure protruding from a first surface of the shielding plate facing the first space toward the first space, A sound absorbing device for a vehicle.

[0073] According to Supplementary Note 8 above, the vehicle sound-absorbing device forms a resonant system consisting of a spring and mass. The sound-absorbing structure protruding from the shielding plate toward the first space functions as the mass of the resonant system. The rigidity of the shielding plate, the rigidity of the sound-absorbing structure, and the elasticity of the air in the second space function as the spring of the resonant system. This allows the vehicle sound-absorbing device to absorb sound, while the sound-absorbing structure increases the mass of the resonant system and suppresses fluctuations in the resonant frequency. As a result, while a sound-absorbing effect is obtained, the volume occupied by the sound-absorbing device around the communication opening is reduced compared to a sound-absorbing device arranged along the periphery of the communication opening.

[0074] [Appendix 9] The shielding plate and the sound absorbing structure are integrated together. 9. A vehicle sound absorbing device according to any one of appendices 1 to 8.

[0075] According to Supplementary Note 9, since the shielding plate and the sound absorbing structure are integrated, it is possible to prevent an increase in the number of components of the sound absorbing device and also to reduce the cost required for absorbing sound in the ventilation space. [Explanation of symbols]

[0076] 10...Sound absorbing device 10M…shielding plate 10M1…First page 10M2…Second side 11...Sound-absorbing structure 12...Board body 13…Outer peripheral wall 14...Inner peripheral wall 15...Sound-absorbing board 50S: Ventilated space 50S1…1st space 50S2…Second space 51...Rear bumper 52...Rear side member 53...Communication port 54...Vent duct 61...adhesive layer 62...Elastic body

Claims

1. A sound absorbing device for a vehicle, the sound absorbing device including a communication port in the vehicle interior that communicates a ventilation space, which is a space between a vehicle exterior and a vehicle interior, with a vehicle compartment, the communication port being provided in the ventilation space, the sound absorbing device being arranged in the ventilation space, a shielding plate that is connected to the vehicle exterior and the vehicle interior to separate the ventilation space into a first space in which the communication port is disposed and a second space other than the first space; a sound absorbing structure protruding from a first surface of the shielding plate facing the first space toward the first space. A sound absorbing device for a vehicle.

2. the shielding plate has a shape extending in the front-rear direction of the vehicle, the sound-absorbing structure includes a plurality of sound-absorbing plates arranged in a direction intersecting the front-rear direction, The sound-absorbing plate has a wave shape that continues in the front-rear direction when viewed from a viewpoint opposite to the first surface. The sound absorbing device for a vehicle according to claim 1.

3. one of the vehicle interior and the vehicle exterior is a first exterior; Among the vehicle interior and the vehicle exterior, the one other than the first exterior is a second exterior, The shielding plate is fixed to the first exterior so as to be swingable relative to the second exterior.

3. The sound absorbing device for a vehicle according to claim 1 or 2.

4. one of the vehicle interior and the vehicle exterior is a first exterior; Among the vehicle interior and the vehicle exterior, the one other than the first exterior is a second exterior, The shielding plate is fixed to the first exterior via an adhesive layer and is supported by the second exterior via an elastic body.

3. The sound absorbing device for a vehicle according to claim 1 or 2.

5. the shielding plate includes a reinforcing rib protruding from the first surface toward the first space, the reinforcing rib has a linear shape extending in a direction intersecting the front-rear direction when viewed from a viewpoint facing the first surface, The plurality of sound-absorbing plates include the sound-absorbing plates connected to the reinforcing ribs. The sound absorbing device for a vehicle according to claim 2.

6. the shielding plate includes two reinforcing ribs protruding from the first surface toward the first space, the reinforcing ribs have a linear shape extending in a direction intersecting the front-rear direction when viewed from a viewpoint opposite the first surface, and are aligned in the front-rear direction; The plurality of sound-absorbing plates include a sound-absorbing plate disposed between the two reinforcing ribs and connected to the two reinforcing ribs.

6. The sound absorbing device for a vehicle according to claim 5.

7. The shielding plate and the sound absorbing structure are integrated.

3. The sound absorbing device for a vehicle according to claim 1 or 2.

Images