Sound absorbing structure and vehicle having the same

Abstract

To provide a sound absorbing structure capable of effectively reducing noise entering from a vent duct with a simple configuration, and a vehicle equipped with the same.SOLUTION: This sound absorbing structural body 5 has an installing part 51, a vertical 55b part 52 and a sound absorbing body part 55 (a side 55a and a side 75b), and is arranged on the cabin side 90 across a space part 75 (a side 75a and a side wall) between itself and a vent duct 60. The sound absorbing structure 5 includes felt as a sound absorbing material. The sound absorbing body portion 55 (55a, 55b) is disposed substantially parallel to the opening surface of the vent hole 60h provided in the vent duct 60. The sound absorbing structure 5 is attached to the outer peripheral portion 61 of the vent duct 60 via the attachment portion 51. The attachment portion 51 extends in a direction opposite to the sound absorbing body portion 55 (side 55a, 55b) with the standing wall portion 52 interposed therebetween.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a sound absorbing structure and a vehicle equipped with the same, and more particularly to a sound absorbing structure that can effectively reduce noise entering through a vent duct with a simple configuration, and a vehicle equipped with the same. [Background technology]

[0002] Vehicles are provided with ventilation vent ducts to prevent the doors from becoming difficult to close due to high air pressure inside the vehicle when closing the doors. Vent ducts are usually installed on the bumper, deck side, etc. of the vehicle. However, there is a problem in that noise from outside the vehicle enters the interior of the vehicle through the opening of the vent duct. In particular, in the rear seats of the vehicle, there is a problem in that noise from the tires is loud when the vehicle is moving, and the noise entering from the deck side near the tires is loud. Therefore, there is a need for a means for suppressing outside noise from entering the interior of the vehicle while maintaining the ventilation of the vent duct.

[0003] Here, a structure of a vehicle vent duct that suppresses the intrusion of sound from outside the vehicle through the vent duct has been proposed (see, for example, Patent Document 1). The vehicle vent duct described in Patent Document 1 has a duct body formed by connecting an outer frame and an inner frame arranged on either side of an opening in a rear quarter panel, and a sound-absorbing member arranged in the duct body to form an air flow path. The sound-absorbing member has protrusions and valleys arranged in a staggered pattern, with one protrusion facing the other valley and the other protrusion nested between the protrusions. With this structure, sound entering through the ventilation opening on the outside of the vehicle collides with the protrusion and is thereby attenuated, thereby reliably suppressing outside sound leaking into the vehicle interior through the vent duct. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-12575 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the vent duct structure described in Patent Document 1 requires multiple sound-absorbing members (soft urethane foam, glass wool, etc.) with staggered projections and valleys. In other words, the sound-absorbing members must be molded into complex shapes. Furthermore, the sound-absorbing members must be positioned opposite each other and held with a flow path between them. In other words, a precise holding structure is required. This requires an outer and inner housing frame to house the sound-absorbing members. Thus, the technology described in Patent Document 1 requires complex shapes, multiple components, and a precise holding structure for these components, in exchange for excellent sound-absorbing performance, resulting in the problem of high costs for the vent duct.

[0006] The present invention has been made in view of the above-mentioned circumstances, and has an object to provide a sound-absorbing structure that exhibits excellent sound-absorbing performance with a simple structure and configuration, and a vehicle equipped with the same. [Means for solving the problem]

[0007] The present invention is as follows. 1. A vehicle equipped with a sound-absorbing structure that covers a vent duct provided in the vehicle, the sound-absorbing structure having a mounting portion, a vertical wall portion, and a sound-absorbing main body portion, and the sound-absorbing structure is positioned on the interior side of the vehicle with a space between it and the vent duct. 2. A vehicle equipped with the sound-absorbing structure described in 1., wherein the sound-absorbing structure is equipped with felt as a sound-absorbing material. 3. A vehicle equipped with the sound-absorbing structure described in 1. or 2., wherein the sound-absorbing main body portion is made of the sound-absorbing material and is arranged approximately parallel to the opening surface of the air vent provided in the vent duct. 4. A vehicle equipped with a sound-absorbing structure described in any one of 1. to 3., wherein the sound-absorbing structure has two standing wall portions for one sound-absorbing main body portion, and the standing wall portions extend from the side ends of the sound-absorbing main body portion to form the space portion between the vent duct and the sound-absorbing main body portion. 5. A vehicle equipped with a sound-absorbing structure according to any one of 1. to 4., wherein the sound-absorbing structure is attached to the outer periphery of the vent duct via the mounting portion. 6. A vehicle equipped with a sound-absorbing structure described in any one of 1. to 5., wherein the mounting portion extends in the opposite direction to the sound-absorbing main body portion, sandwiching the vertical wall portion. 7. A vehicle equipped with a sound-absorbing structure according to any one of 1. to 6., wherein the vent duct is provided on the deck side. 8. A vehicle equipped with a sound-absorbing structure according to any one of 1. to 7., wherein the vent duct is located above the rear tire housing. 9. A vehicle equipped with a sound-absorbing structure according to any one of 1. to 8., wherein the mounting portion and / or the standing wall portion is made of sound-absorbing material. 10. A sound absorbing structure characterized by being used in a vehicle equipped with the sound absorbing structure described in any one of 1. to 9. [Effects of the Invention]

[0008] According to the present invention, there is provided a vehicle equipped with a sound absorbing structure that covers a vent duct provided in the vehicle, the sound absorbing structure having a mounting portion, a standing wall portion, and a sound absorbing main body portion, and the sound absorbing structure is disposed on the interior side of the vehicle with a space between it and the vent duct. Therefore, it is possible to provide a vehicle equipped with a sound absorbing structure that can effectively reduce the intrusion of outside noise from the vent duct with a simple configuration.

[0009] Furthermore, when the sound-absorbing structure is equipped with felt as the sound-absorbing material, the simple material of felt can provide excellent sound-absorbing performance, thereby effectively reducing the intrusion of outside noise into the vehicle interior.

[0010] Furthermore, when the sound-absorbing main body is made of sound-absorbing material and is arranged approximately parallel to the opening of the air vent of the vent duct, it is possible to absorb external noise that attempts to enter the vehicle interior through the air vent from the front, facing the path of the intrusion, thereby effectively reducing the intrusion of external noise into the vehicle interior beyond the sound-absorbing structure.

[0011] Furthermore, if the sound-absorbing structure has two upright walls for one sound-absorbing main body, and the upright walls extend from the side edges of the sound-absorbing main body to form a space between the vent duct and the sound-absorbing main body, it is possible to maintain high breathability between the inside and outside of the vehicle while absorbing outside noise that tries to enter the vehicle interior through the air vents in front of the intrusion path. This makes it possible to achieve excellent sound-absorbing performance while maintaining the exhaust function of the vent duct.

[0012] Furthermore, when the sound absorbing structure is attached to the outer periphery of the vent duct via the attachment part, the sound absorbing body can be reliably fixed in an appropriate position relative to the vent duct, thereby achieving excellent sound absorbing performance while maintaining the exhaust function of the vent duct.

[0013] Furthermore, when the mounting portion extends in the opposite direction to the sound-absorbing main body, sandwiching the vertical wall portion therebetween, the sound-absorbing main body can be reliably fixed in an appropriate position relative to the vent duct while maintaining an appropriate space between the sound-absorbing main body and the vent duct, thereby achieving excellent sound-absorbing performance while maintaining the exhaust function of the vent duct.

[0014] Furthermore, when the vent duct is provided on the deck side, i.e., when the vent duct is provided on the side of the vehicle behind the rear seats, it is particularly effective in creating a quiet environment in the rear of the vehicle. That is, vehicles usually have a trunk space adjacent to the deck side. The trunk space is a large space when no luggage is loaded, and therefore has few structures that can attenuate or reduce external noise that enters the vehicle interior, making it difficult to contribute to creating a quiet environment in the rear seats. In this regard, when the above-mentioned sound-absorbing structure is provided for the vent duct provided on the deck side, it can effectively suppress the intrusion of external noise, thereby significantly contributing to creating a quiet environment in the rear seats.

[0015] Furthermore, when the vent duct is located above the rear tire housing, it can contribute particularly effectively to creating a quiet environment inside the vehicle. Specifically, the rear tire housing houses the tires, and while the vehicle is running, it generates noise (contact noise) caused by the tires coming into contact with the road surface. This contact noise is one of the loudest noises outside the vehicle. In particular, in hybrid vehicles and electric vehicles, where noise generated by the internal combustion engine is eliminated or reduced, the impact of this contact noise is particularly significant. Furthermore, as mentioned above, the trunk space located above the rear tire housing of a vehicle makes it difficult to attenuate or reduce intruding noise, making the configuration unfavorable for creating a quiet environment for various reasons. In this regard, when the above-mentioned sound-absorbing structure is provided for the vent duct located above the rear tire housing, it can effectively suppress the intrusion of outside noise, thereby significantly contributing to creating a quiet environment in the rear seats.

[0016] Furthermore, if the mounting portion and / or the standing wall portion are made of sound-absorbing material, these components can also have a sound-absorbing effect, and the synergistic effect with the sound-absorbing main body portion can further prevent noise. When the sound absorbing structure of the present invention is used in a vehicle, it can effectively prevent noise. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic explanatory diagram showing a sound absorbing structure according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a schematic explanatory diagram showing a sound absorbing structure according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a schematic explanatory diagram showing a sound absorbing structure according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic explanatory diagram showing a sound absorbing structure according to a fourth embodiment of the present invention. [Figure 5] 1 is a schematic perspective view showing the periphery of a luggage compartment of a vehicle according to an embodiment of the present invention; [Figure 6] 1 is a schematic perspective view showing an example in which a sound absorbing structure according to an embodiment of the present invention is attached to a vent duct on a deck side. [Figure 7] 1 is a schematic explanatory diagram showing a sound absorbing structure according to an embodiment of the present invention; [Figure 8] 1 is a schematic perspective view showing a sound absorbing structure according to an embodiment of the present invention. [Figure 9] FIG. 10 is a schematic perspective view showing a sound absorbing structure according to a modified embodiment of the present invention. [Figure 10] FIG. 2 is an explanatory diagram showing the positions of a microphone and a speaker of a vehicle according to an embodiment of the present invention. [Figure 11] 1 is a graph showing acoustic vibration sensitivity according to Examples 1 and 2 of the present invention and Comparative Example 1. [Figure 12] 12 is a graph showing the effect in FIG. 11. [Figure 13] 10 is a graph showing sound pressure levels at the ear position of the rear seat left window in an actual driving evaluation according to Example 3 of the present invention and Comparative Example 2. [Figure 14] 14 is a graph showing a comparison of OA values ​​in FIG. 13. [Figure 15] 10 is a graph showing sound pressure levels of sounds near the LH deck side in an actual driving evaluation according to Example 3 of the present invention and Comparative Example 2. [Figure 16] 16 is a graph showing a comparison of OA values ​​in FIG. 15. DETAILED DESCRIPTION OF THE INVENTION

[0018] A vehicle equipped with a sound-absorbing structure of the present invention includes a sound-absorbing structure covering a vent duct provided in the vehicle, the sound-absorbing structure having a mounting portion, a standing wall portion, and a sound-absorbing main body portion. The sound-absorbing structure is also disposed on the interior side of the vehicle with a space between it and the vent duct.

[0019] The "sound-absorbing structure" is a structure that is placed inside the vehicle, separated by a space between it and the vent duct. That is, by separating the space, it is a structure that can maintain air circulation between the inside and outside of the vehicle through the vent duct. Furthermore, by having at least a sound-absorbing main body portion, it is a structure that functions to absorb (including attenuate) outside noise that attempts to enter the vehicle interior through the vent duct, thereby suppressing the intrusion of outside noise into the vehicle interior.

[0020] A "vehicle" is a wheeled vehicle, and for the purposes of this application, refers to a vehicle having a cabin. The cabin is used, for example, as a space for accommodating occupants (including at least a driver who operates the vehicle) and cargo. In this application, the inside of the cabin is also referred to as the interior of the vehicle, and the outside of the vehicle is also referred to as the exterior of the vehicle. Also, in this application, a vehicle typically has a door separating the cabin from the exterior of the vehicle for passengers to travel between the cabin and the exterior and for loading and unloading cargo. The number of wheels a vehicle has is not limited, but can be, for example, three or more, or even four or more, and typically has 20 or fewer wheels.

[0021] In the present application, the vehicle is not limited to any vehicle equipped with a vent duct, and includes, for example, automobiles, railway vehicles, etc. Among these, in the present application, automobiles are preferred from the viewpoint of the effects. Among automobiles, for example, standard automobiles (standard passenger cars, buses, trucks, etc.), light automobiles (light passenger cars, light trucks, etc.), and compact automobiles are suitable.

[0022] A "vent duct" refers to a part provided in a vehicle that allows air to circulate between the inside and outside of the vehicle. That is, it is a part that allows air to circulate between the inside and outside of the vehicle. Therefore, a vent duct can function, for example, to prevent an increase in pressure inside the vehicle when closing a door of the vehicle, making it difficult to close the door. There is no limit to the number of vent ducts that a vehicle can have, and it is sufficient to have one or more, but it can also have two or more, three or more, four or more, and the number is usually 20 or less.

[0023] The installation position, structure, shape, size, air flow rate, constituent material, etc. of the vent duct are not limited, but for example, the installation position may be the outer periphery of the wheelhouse (rear wheelhouse, front wheelhouse, etc.), the upper rear part of the wheelhouse (rear wheelhouse, front wheelhouse, etc.), the rear part of the back door, the rear part of the luggage compartment, the area around the trunk opening, inside the back bumper, etc. Among these, the sound absorbing structure 1 can be positioned above the rear tire housing to obtain the effects of the present invention more remarkably. That is, it can contribute particularly effectively to creating a quiet environment inside the vehicle.

[0024] The rear tire housing houses the rear tires, and while the vehicle is traveling, road noise is generated as the tires come into contact with the road surface. This road noise is one of the loudest sounds outside the vehicle. In particular, in hybrid vehicles and electric vehicles, where noise from the internal combustion engine is eliminated or reduced, the impact of this contact noise is particularly significant. Furthermore, the trunk space located above the rear tire housing of the vehicle makes it difficult to attenuate or reduce intruding noise, making the configuration unfavorable for creating a quiet environment for various reasons. In this regard, if the above-described sound-absorbing structure 1 is provided for the vent duct 60 located above the rear tire housing, the intrusion of road noise can be effectively suppressed, thereby significantly contributing to creating a quiet environment in the rear seats.

[0025] Furthermore, as tire size increases, the mass of the tire itself increases and the tire width also increases, which tends to increase the amount of road noise. Therefore, the advantageous effects of the present invention can be more effectively achieved in vehicles with relatively large tire housings than in vehicles with relatively small tire housings. Specifically, it is preferable to apply the sound-absorbing structure 1 of the present application to a vent duct provided above a tire housing that can accommodate tires with a diameter of more than 500 mm, and it is even more preferable to apply the sound-absorbing structure 1 of the present application to a vent duct provided above a tire housing that can accommodate tires with a diameter of 550 mm or more, 600 mm or more, or 650 mm or more (usually 1000 mm or less).

[0026] Furthermore, for example, the structure can be composed of a hole opened in a body panel of a vehicle, a resin frame installed along the inner periphery of the hole, a plurality of louvers (such as plate-like bodies arranged diagonally so that they are closed at the top and open at the bottom to prevent wind and rain from blowing in) placed on the left and right sides of the frame so that they are approximately horizontal to each other, and a perforated sheet (such as a mesh or sponge-like material) placed on the inside of the frame to cover the opening of the frame.

[0027] Hereinafter, a sound-absorbing structure and a vehicle equipped with the same will be described in detail using embodiments. However, the present invention is not limited to these embodiments. These embodiments are merely examples shown for the convenience of explanation, and the present invention is not limited to these embodiments in any sense. The present invention can be modified in various ways depending on the purpose and application. Furthermore, all publications, patents, and patent applications cited in this disclosure are incorporated herein by reference in their entirety.

[0028] [Embodiment 1] A vehicle (not shown) equipped with a sound absorbing structure 1 according to the first embodiment includes, as shown in FIG. 1, a sound absorbing structure 1 that covers a vent duct 60 provided in the vehicle. The vent duct 60 is provided on the body panel 65 of the vehicle, and has an air vent 60h that opens on one side to the outside 80 of the vehicle and on the other side to the inside of the vehicle, and further allows air to flow from a gap (not shown) in the deck side trim 75 that covers the vent duct to the inside 90 of the vehicle. The sound-absorbing structure 1 has a mounting portion 11, a standing wall portion 12, and a sound-absorbing main body portion 15. In this way, the sound-absorbing structure 1 can absorb sounds (road noise, commotion) that are generated by contact between a tire 85 of a vehicle and the road surface, particularly when the tire 85 travels on the road surface.

[0029] The sound absorbing structure 1 is not particularly limited to any material as long as it has a sound absorbing function, but a fiber-based material or a urethane-based material can be used as the sound absorbing material. Among these, fibrous materials are materials primarily composed of fibers, and can be materials in which the mass ratio of fibers to the total material is, for example, 50% by mass or more. More specifically, examples include felt (needle-processed aggregated fibers, compressed fibers, etc.), nonwoven fabrics, carpets, and compressed mixtures of fibers and foam (urethane foam, etc.). The constituent fibers may be recycled fibers, virgin fibers, or both. The type of constituent fibers is not limited, and examples include synthetic fibers (acrylic, polyester, nylon, etc.), semi-synthetic fibers (staple fiber, etc.), and natural fibers (cotton, linen, wool, etc.). Furthermore, binders (thermoplastic resins, starch powder, etc.) may be included to bind these fibers and coexisting components.

[0030] Furthermore, as the urethane-based material, urethane foam (soft urethane foam, hard urethane foam, etc.) can be used. Among these, fibrous materials are preferable, and felt made mainly of synthetic fibers, cotton, etc., can be made to have particularly excellent sound absorption properties.

[0031] The basis weight and thickness of the sound absorbing material are not limited, but for example, the basis weight is 400 to 1500 g / m 2 Furthermore, the basis weight can be set to 500 to 1400 g / m 2Furthermore, the basis weight can be set to 600 to 1300 g / m 2 , and a basis weight of 700 to 1200 g / m 2 The thickness of the sound-absorbing material can be, for example, 3 to 50 mm, further 4 to 45 mm, further 5 to 40 mm, further 6 to 35 mm, further 7 to 30 mm, and further 8 to 25 mm. The thickness of the sound-absorbing material is measured in its natural state without applying any load to the sound-absorbing material (so that it is not compressed), and is the average value of thicknesses at 50 random points.

[0032] The "mounting portion 11" is a part of the sound absorbing structure 1, and is a portion for arranging the sound absorbing structure 1 so that it is fixed at a predetermined position relative to the vent duct 60. The "predetermined position" is not particularly limited, and like the mounting portion 11 in embodiment 1, it may be attached to the top or bottom end positions relative to the vent duct 60, but it can also be attached to the left or right end positions (the same applies to embodiments 2 to 4 below). The mounting portion 11 is connected to the sound-absorbing main body portion 15 via the standing wall portion 12 described below. There are no particular limitations on the shape of the mounting portion 11 as long as it can mount the sound-absorbing structure 1 so as to cover the vent duct 60, but it is preferable that the mounting portion 11 has a shape (for example, a flat plate shape, a curved shape, etc.) that conforms to the joint surface so as to increase the joint surface (the joint surface between the vehicle, body, etc. and the mounting portion 11). There are no particular limitations on the number of mounting portions 11 that the sound-absorbing structure 1 has, but from the perspective of supporting the standing wall portion 12 described below, there can be two. The material of the mounting portion 11 is not limited and can be metal, wood, or resin, but among these, resin is preferable, and from the viewpoint of damping sound vibrations, soft resin is even more preferable.

[0033] The "standing wall portion 12" is a portion that connects the mounting portion 11 and the sound-absorbing main body portion 15, and connects them at an angle that intersects with the plane formed by the sound-absorbing main body portion 15. In other words, it is a portion that is disposed like a standing wall relative to the sound-absorbing main body portion 15. The angle between the sound-absorbing main body portion 15 and the standing wall portion 12 is not limited, but can be, for example, 45 to 90 degrees, 60 to 90 degrees, or 70 to 90 degrees. Similarly, the standing wall portion 12 can be connected to the mounting portion 11 and erected relative to the mounting portion 11.

[0034] The sound absorbing structure 1 has the standing wall portion 12, which makes it possible to secure a space between the sound absorbing main body 15 and the vent duct 60. The size and shape of the space can be controlled by adjusting the length, attachment angle, etc. of the standing wall portion 12. The number of standing wall portions 12 provided in one sound-absorbing structure 1 is not particularly limited, but if there are two mounting portions 11, two standing wall portions 12 can be provided to connect to each mounting portion 11 to support one sound-absorbing main body 15. That is, for example, if the sound-absorbing main body 15 is substantially rectangular, two standing wall portions 12 and two mounting portions 11 can be provided in pairs on opposing sides of the sound-absorbing main body 15 in plan view. In this embodiment, of the opposing sides of the sound-absorbing main body 15 in plan view, the two sides not connected to the standing wall portions 12 are open via the above-mentioned space, which prevents obstruction of air flow as needed.

[0035] The material constituting the standing wall portion 12 is not limited and can be metal, wood, resin, or the like, with resin being preferred among these. Furthermore, as mentioned above, from the viewpoint of sound vibration attenuation, a soft resin is even more preferred. That is, when the standing wall portion 12 is formed from resin, a phenomenon known as membrane resonance sound absorption or membrane vibration sound absorption occurs, in which the standing wall portion 12 itself vibrates as a plate or membrane, thereby consuming a portion of the sound energy through internal friction, thereby improving the quietness of the vehicle interior. That is, sound energy can be attenuated by converting it into thermal energy inside the resin that constitutes the standing wall portion 12.

[0036] The standing wall portion 12 extends from the side end of the sound-absorbing main body portion 15, forming a space portion 71 between the vent duct 60 and the sound-absorbing main body portion 15. By forming the space portion 71, the sound-absorbing structure 1 does not directly block the vent duct 60, and therefore the exhaust function of the vent duct 60 is not hindered.

[0037] The "sound-absorbing main body 15" is made of a sound-absorbing material. The material is as explained in the above paragraph

[0010] , and felt is particularly preferable. The shape of the sound-absorbing main body 15 is not particularly limited, but it is a rectangular plate to match the shape of the vent duct 60, and is arranged approximately parallel to the opening surface of the air vent 60h provided in the vent duct 60. By arranging the sound-absorbing main body 15 approximately parallel to the opening surface of the air vent 60h, noise from the air vent 60h can be absorbed from the front, thereby achieving even more effective noise reduction. Note that the above-mentioned "substantially parallel to the opening surface" includes, for example, a state in which the angle formed between the opening surface and the sound absorbing main body 15 is 20 degrees or less, further 10 degrees or less, and particularly 5 degrees or less.

[0038] [Embodiment 2] A vehicle (not shown) equipped with a sound absorbing structure 2 according to the second embodiment includes, as shown in FIG. 2, a sound absorbing structure 2 that covers a vent duct 60 provided in the vehicle. The sound absorbing structure 2 according to the second embodiment has an attachment portion 21, a standing wall portion 22, and a sound absorbing main body portion 25. The sound absorbing structure 2 is attached to the outer periphery 61 of the vent duct 60 via the attachment portion 21. This allows the sound absorbing structure 2 to be reliably fixed to the outer periphery 61 of the vent duct 60. Furthermore, the mounting portion 21 extends in the opposite direction to the sound-absorbing main body portion 25, sandwiching the standing wall portion 22. This allows the sound-absorbing structure 2 to be fixed to the body panel 65 in a stable manner.

[0039] Furthermore, because the gap between the body panel 65 and the deck side trim 75 is wide, the vertical wall portion 22 can be made longer in the extending direction, and the sound-absorbing main body portion 25 can be made up of a first sound-absorbing main body portion 25a and a second sound-absorbing main body portion 25b provided parallel to the first sound-absorbing main body portion 25a. With this configuration, the space portion 72 is made up of the first space portion 72a and the second space portion 72b, which can further efficiently improve the sound-absorbing effect. The other configurations and effects of the mounting portion 21, the standing wall portion 22, and the sound-absorbing main body portion 25 are the same as those of the mounting portion 11, the standing wall portion 12, and the sound-absorbing main body portion 15 of the sound-absorbing structure 1 of embodiment 1, so explanations will be omitted.

[0040] [Embodiment 3] A vehicle (not shown) equipped with a sound absorbing structure 3 according to the third embodiment includes, as shown in FIG. 3, a sound absorbing structure 3 that covers a vent duct 60 provided in the vehicle. The sound absorbing structure 3 according to the third embodiment has an attachment portion 31, a standing wall portion 32, and a sound absorbing main body portion 35. The sound absorbing structure 3 is attached to the outer periphery 61 of the vent duct 60 via the attachment portion 31. Furthermore, the attachment portion 31 extends in the opposite direction to the sound absorbing main body portion 35, with the standing wall portion 32 sandwiched between them.

[0041] The standing wall portion 32 and the sound-absorbing main body portion 35 are formed integrally to form a space portion 73. That is, the standing wall portion 32 is made of a sound-absorbing material, just like the sound-absorbing main body portion 35. This improves sound absorption performance compared to when only the sound-absorbing main body portion 35 is made of a sound-absorbing material. The other configurations and effects of the mounting portion 31 are the same as those of the mounting portion 21 according to embodiment 2, and the material of the sound-absorbing main body portion 35 is the same as that of the sound-absorbing main body portion 15, so a description thereof will be omitted.

[0042] [Embodiment 4] A vehicle (not shown) equipped with a sound absorbing structure 4 according to the fourth embodiment includes the sound absorbing structure 4 that covers a vent duct 60 provided in the vehicle, as shown in FIG. The sound absorbing structure 4 according to the fourth embodiment has a mounting portion 41 , a standing wall portion 42 , and a sound absorbing main body portion 45 . Except for the fact that the mounting portion 41 is made of sound-absorbing material, it is the same as the sound-absorbing structure 3 according to embodiment 3. That is, the mounting portion 41, the standing wall portion 42, and the sound-absorbing main body portion 45 are formed integrally with each other to form a space portion 74. That is, the mounting portion 41, like the standing wall portion 42 and the sound-absorbing main body portion 45, is made of sound-absorbing material. This makes it possible to further improve the sound-absorbing performance. The other configurations and effects of the sound-absorbing structure 4 are the same as those of the sound-absorbing structure 3 according to embodiment 3, so a description thereof will be omitted. [Example]

[0043] The present invention will be explained in more detail below with reference to examples. As shown in FIG. 5, the surrounding structure of the luggage area of ​​the vehicle 100 according to the embodiment is covered by an LH deck side trim 102 on the left side of the rear seat 101, an RH deck side trim 103 on the right side, and a deck board 104 on the lower side. When the LH deck side trim 102 is removed, the vent duct 60 attached to the body panel 65 appears, as shown in Fig. 6. The vent duct 60 may be provided on the deck side as in this embodiment, but may also be located above the rear tire housing 67.

[0044] The sound-absorbing structure 5 according to the embodiment is provided to cover the vent duct 60, and as shown in Figures 7 and 8, has mounting portions 51 to be attached to the upper and lower ends of the vent duct 60, a standing wall portion 52, and a sound-absorbing main body portion 55, all of which are integrally formed from felt made from a blend of synthetic fiber and cotton. The sound-absorbing structure 5 is attached to the outer periphery 61 of the vent duct 60 via an attachment portion 51. Furthermore, the attachment portion 51 extends in the opposite direction to the sound-absorbing main body portion 55, sandwiching the standing wall portion 52 therebetween. Because the gap between the body panel 65 and the deck side trim 102 is wide, the standing wall portion 52 can be made long in the direction in which it extends, and the sound-absorbing main body portion 55 consists of a first sound-absorbing main body portion 55a and a second sound-absorbing main body portion 55b that is provided parallel to the first sound-absorbing main body portion 55a. Other configurations and effects of the mounting portion 51, the standing wall portion 52 and the sound absorbing main body portion 55 are the same as those described in the first to fourth embodiments, and therefore description thereof will be omitted. 9, the sound absorbing structure 5A can also be attached to the left and right ends of the vent duct 60. The sound absorbing structure 5A has mounting portions 51A that are attached to the left and right ends of the vent duct 60, a standing wall portion 52A, and a sound absorbing main body portion 56A, which consists of a first sound absorbing main body portion 56a and a second sound absorbing main body portion 56b that is provided in parallel to the first sound absorbing main body portion 56a. Other configurations and effects of the mounting portion 51A, the standing wall portion 52A and the sound absorbing main body portion 56A are the same as those explained in the sound absorbing structure 5 according to the embodiment, and therefore explanation thereof will be omitted.

[0045] [Performance evaluation] (1) Acoustic excitation sensitivity evaluation <Evaluation method> As shown in Fig. 10, speaker S was installed at the ear position of the rear seat left window of vehicle 100 as the excitation point, and microphones M1, M2, M3, and M4 were installed at four locations near rear left LH tire 85 as measurement points. The sound from speaker S was detected by microphones M1, M2, M3, and M4 to evaluate the acoustic excitation sensitivity.

[0046] "Acoustic excitation sensitivity" is the acoustic transfer function from the sound source to the ear position, and in the vibration / noise (N / V) field, acoustic excitation sensitivity remains the same even if the sound source (speaker position) and measurement point (microphone position) are swapped (reciprocity theorem). In other words, P tire noise and Q interior noise are affected by H spring multiplier, and the magnifications of P and Q do not change even if they are reversed. Therefore, the reciprocity theorem holds true even if the measurement location is changed.

[0047] [Table 1]

[0048] The acoustic excitation sensitivity was evaluated for three examples: Comparative Example 1, Example 1, and Example 2 shown in Table 1. Here, the acoustic excitation sensitivity is expressed as the value of (sound pressure level at the measurement point) / (volume velocity of the acoustic excitation source). The sound pressure level is the strength level of the air pressure fluctuation occurring at the measurement point. As shown in Figure 7, evaluations were conducted for three cases: Comparative Example 1, where only a conventional sound-absorbing material 97 (hereinafter referred to as the "conventional product") that is attached to commercially available vehicles was attached to the deck side trim 102; Example 1, where only the sound-absorbing structure 5 according to the embodiment (hereinafter referred to as the "implemented product") was attached to the body panel 65; and Example 2, where the conventional product was attached to the deck side trim 102 and the implemented product was attached to the body panel 65.

[0049] The tire house can accommodate a tire with a diameter of at least 700 to 750 mm. In Comparative Example 1, the conventional sound absorbing material is a nonwoven fabric containing polypropylene meltblown fibers with a fiber diameter of 50 μm or less and polyester short fibers, and has a basis weight of 332 g / m2. In Comparative Example 1, the conventional sound absorbing material is 0.30 m thick on the body panel side of the deck side trim 102. 2 Furthermore, in Examples 1 and 2, the felt constituting the sound absorbing structure of the examples is a nonwoven fabric containing recycled fibers (polyester fiber, acrylic fiber, cotton fiber, rayon fiber, animal hair fiber, nylon fiber, etc.), and has a basis weight of 800 g / m 2 The area of ​​the spread felt is 0.12m 2 is.

[0050] <Evaluation results> As shown in FIG. 11 , when comparing the acoustic excitation sensitivity of the conventional product of Comparative Example 1 with that of the implemented product of Example 1, the acoustic excitation sensitivity of the comparative product was slightly better than that of the implemented product in the frequency band of 400 to 500 Hz, the 1 / 3 octave frequency of speaker S. However, the acoustic excitation sensitivity of the implemented product was particularly better than that of the comparative product in the frequency band of 630 to 1250 Hz. This frequency band of 630 to 1250 Hz is the second most important band used for conversation in vehicles, after the frequency band of 1600 to 3150 Hz, and has a higher contribution than frequency bands below 500 Hz. Therefore, improving sound absorption performance in the frequency band of 630 to 1250 Hz can significantly improve the acoustic environment inside a vehicle. Furthermore, as a comprehensive evaluation, it was confirmed that the implemented product had equivalent performance to the conventional product in the wide frequency band of 400 to 6300 Hz.

[0051] Furthermore, when the conventional product and the implemented product were used together as in Example 2, the acoustic vibration sensitivity was better in the frequency band of 600 to 2500 (Hz) than when the comparative product or the implemented product was used alone. In Example 2 as well, by installing the implemented product, a significant improvement in sound absorption performance was obtained in the frequency band of 600 to 1200 (Hz), and the acoustic environment inside the vehicle could be significantly improved. Furthermore, as shown in FIG. 12, in terms of the effect, the difference between Comparative Example 1 as the reference shows that Example 1 improves by 0.17 (dB) and Example 2 improves by 0.51 (dB), which indicates a more significant improvement in terms of the effect.

[0052] Furthermore, when the materials used for the sound absorbing material in Comparative Example 1 and Example 1 are compared, the material used in Comparative Example 1 is 0.30 m 2 In contrast, the material used in Example 1 was 0.12 m 2, which is only 40% of that of Comparative Example 1. In other words, the above-mentioned effects are achieved while reducing the area constituting the sound-absorbing material by 60%. Furthermore, while the conventional sound-absorbing material of Comparative Example 1 requires work to spread it over almost the entire surface of one side of the deck side trim 102 and attach it, the sound-absorbing structure 5 of Example 1 can be penetrated and fixed with clips via its mounting portion. In other words, excellent installation work efficiency can be achieved. Furthermore, it is possible to install the practical product while laying the conventional product, thereby improving performance (quietness) at low cost.

[0053] (2) Actual driving evaluation <Evaluation method> The vehicle 100 was actually driven to perform a real-world driving evaluation. The evaluation road surface was a normal asphalt-paved road, and the vehicle was driven at a steady speed of 60 km / h. Measurement points were located at the ear position of the left window side of the rear seat of the vehicle 100 and a position near the left-hand deck side. In the real-world driving evaluation, tires with a size of 225 / 65R17 were used.

[0054] [Table 2]

[0055] An actual driving evaluation was carried out for Comparative Example 2 and Example 3 shown in Table 2. Comparative Example 2 is a case where only the conventional product was attached to the deck side trim 102, and Example 3 is a case where only the implementation product was attached to the body panel 65.

[0056] <Evaluation results> (a) Rear seat left window side ear position 13, when comparing the sound pressure levels of the conventional product of Comparative Example 2 and the implemented product of Example 3, the implemented product had a slightly better sound pressure level than the comparison product in the frequency band of 1 / 3 octave center frequencies of 2500 to 6300 (Hz). Furthermore, in a comprehensive evaluation over the wide frequency band of 1 / 3 octave center frequencies of 400 to 6300 (Hz), it was confirmed that the implemented product alone had performance equivalent to that of the conventional product. As shown in FIG. 14, the total sound pressure level (dB) of the entire frequency band from 1 / 3 octave center frequencies of 400 to 6300 (Hz) (hereinafter referred to as the "OA value (dB)"; "OA" is an abbreviation for overall) was 70.07 (dB) for Comparative Example 2 and 69.4 (dB) for Example 3. (b) Near the left hand deck side 15, when comparing the noise pressure levels of the conventional product of Comparative Example 2 and the implemented product of Example 3, the implemented product had a slightly better sound pressure level than the comparison product in the frequency bands of 1 / 3 octave center frequencies of 400 to 1000 (Hz) and 3000 to 6300 (Hz). Furthermore, in a comprehensive evaluation over the wide frequency band of 1 / 3 octave center frequencies of 400 to 6300 (Hz), it was confirmed that the implemented product alone had performance equivalent to that of the conventional product. As shown in FIG. 16, the OA value (dB) was 74.09 (dB) for Comparative Example 2 and 73.36 (dB) for Example 3.

[0057] From the above, the product of Example 3 has performance equal to or better than the conventional product of Comparative Example 2, and is also superior in the following respects. That is, as in the comparison between Comparative Example 1 and Example 1, the material used in Comparative Example 2 was 0.30 m 2 In contrast, the material used in Example 3 was 0.12 m 2 , which is only 40% of that of Comparative Example 2. In other words, the above-mentioned effects are achieved while reducing the area of ​​the sound-absorbing material by 60%. Furthermore, while the conventional sound-absorbing material of Comparative Example 2 requires the work of spreading it over almost the entire surface of one side of the deck side trim 102 and attaching it, the sound-absorbing structure 5 of Example 3 can be penetrated and fixed with clips via its mounting portion. In other words, excellent installation work efficiency can be achieved. Furthermore, it is possible to install the practical product while laying the conventional product, thereby improving performance (quietness) at low cost. [Industrial Applicability]

[0058] The sound absorbing structure of the present invention is industrially applicable in the field of noise control in vehicle cabins. [Explanation of symbols]

[0059] 1, 2, 3, 4, 5; sound-absorbing structure, 11, 21, 31, 41, 51; mounting part, 12, 22, 32, 42, 52; vertical wall section, 15, 25 (25a, 25b), 35, 45, 55 (55a, 55b); Sound absorption body part, 60; vent duct, 60h;ventilation holes, 61;Periphery, 67; rear tire house, 71, 72 (72a, 72b), 73, 74, 75 (75a, 75b); spatial part, 90;Inside the car, 100;vehicle.

Claims

1. A vehicle equipped with a sound absorbing structure covering a vent duct provided in the vehicle, The sound absorbing structure has a mounting portion, a standing wall portion, and a sound absorbing main body portion, A vehicle equipped with a sound absorbing structure, wherein the sound absorbing structure is disposed on an interior side of the vehicle with a space between the sound absorbing structure and the vent duct.

2. The vehicle equipped with a sound absorbing structure according to claim 1, wherein the sound absorbing structure comprises felt as a sound absorbing material.

3. 3. The vehicle equipped with a sound absorbing structure according to claim 2, wherein the sound absorbing main body is made of the sound absorbing material and is disposed substantially parallel to an opening surface of an air hole provided in the vent duct.

4. The sound absorbing structure includes two upright wall portions for one sound absorbing main body portion, 2. A vehicle equipped with a sound-absorbing structure according to claim 1, wherein the upright wall portion extends from a side end of the sound-absorbing main body portion to form the space portion between the vent duct and the sound-absorbing main body portion.

5. The vehicle equipped with a sound absorbing structure according to claim 1 , wherein the sound absorbing structure is attached to an outer periphery of the vent duct via the attachment portion.

6. The vehicle equipped with the sound absorbing structure according to claim 1 , wherein the mounting portion extends in a direction opposite to the sound absorbing main body portion, with the upright wall portion interposed therebetween.

7. 2. A vehicle equipped with a sound absorbing structure according to claim 1, wherein the vent duct is provided on a deck side.

8. 2. A vehicle equipped with a sound absorbing structure according to claim 1, wherein the vent duct is located above a rear tire housing.

9. 2. A vehicle equipped with a sound-absorbing structure according to claim 1, wherein the mounting portion and / or the standing wall portion is made of a sound-absorbing material.

10. A sound absorbing structure for use in a vehicle equipped with the sound absorbing structure according to claim 1.

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