Silencers and interior materials

Abstract

We provide novel noise reduction technology. [Solution] One aspect of the invention is a silencer comprising a housing having a plurality of recesses on its surface and a communication passage connecting the internal spaces of the recesses, and a membrane member that closes the openings of the plurality of recesses, wherein the membrane member is a breathable silencer.

Description

Technical Field

[0001] The present disclosure relates to a muffler and an interior material including the same.

Background Art

[0002] Conventionally, various noise reduction technologies have been proposed (see, for example, Patent Document 1).

Prior Art Document

Patent Document

[0003]

Patent Document 1

[0003] , etc.)

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a novel noise reduction technology.

Means for Solving the Problems

[0005] One aspect of the invention is a muffler including a housing having a plurality of recesses on its surface and a communication passage communicating the internal spaces of the recesses, and a film member closing the openings of the plurality of recesses, wherein the film member is a muffler having air permeability.

Brief Description of the Drawings

[0006] [Figure 1] FIG. 1 is a perspective view of an interior material including the muffler of the first embodiment [Figure 2] FIG. 2 is a side view of the muffler [Figure 3] FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2 [Figure 4] FIG. 4 is an exploded perspective view of the muffler [[ID=六百]] [Figure 5] FIG. 6 is a side view of the housing [Figure 6] FIG. 6 is a perspective view of the overlapping housing and lid member [Figure 7] Figure 7 is a cross-sectional view of line BB in Figure 2. [Figure 8] Figure 8 is a side view of the superimposed housing and lid members. [Figure 9] Figure 9A is a side cross-sectional view of the diaphragm when sound is input to the first diaphragm, and Figure 9B is a side cross-sectional view of the diaphragm when sound is input to the second diaphragm. [Figure 10] Figure 10 is a side view of the silencer according to the second embodiment. [Figure 11] Figure 11 is a cross-sectional view of the CC line in Figure 10. [Figure 12] Figure 12 is an exploded perspective view of the silencer. [Figure 13] Figure 13 is a side view of the housing. [Figure 14] Figure 14 is a cross-sectional view of line DD in Figure 10. [Figure 15] Figure 15 is a side view of the superimposed housing and lid members. [Figure 16] Figure 16A is a side cross-sectional view of the diaphragm when sound is input to the diaphragm, and Figure 16B is a side cross-sectional view of the diaphragm when sound is input to the diaphragm. [Figure 17] Figure 17 is a perspective view of the passenger compartment. [Figure 18] Figure 18 is a plan view of the vehicle showing the noise level measurement locations. [Figure 19] Figure 19 is a graph showing the relationship between frequency and noise level in Example 1 and Comparative Example 1. [Modes for carrying out the invention]

[0007] [First Embodiment] FIG. 1 shows a muffler 10 according to the first embodiment. The muffler 10 is provided, for example, on the wall surface (the wall surface facing the interior side) of an interior material provided in the interior of a vehicle (such as a vehicle 100 or the like). For example, as the interior material provided with the muffler 10, there is a pillar garnish (for example, both left and right pillar garnishes) that is overlaid on a pillar (for example, an A pillar, a B pillar, a C pillar, a D pillar) of the vehicle 100 from the interior side. In the present embodiment, the interior material provided with the muffler 10 is a C pillar garnish 91 that is overlaid on the C pillar of the vehicle 100 from the interior side. For example, the muffler 10 is provided on both left and right pillar garnishes (C pillar garnish 91). Therefore, in the example of the present embodiment, the muffler 10 is disposed near the ears of a passenger sitting by the window of the rear seat.

[0008] In the example of the present embodiment, the muffler 10 includes a housing 11, a film member 30, a lid member 40, and a cover member 50, which are stacked (see FIG. 4), and these are arranged in this order from the back side (see FIG. 3). And the back surface of the muffler 10 (that is, the back surface of the housing 11) is fixed to the main body portion 91H of the interior material (in the example of the present embodiment, to the wall surface of the main body portion 91H of the C pillar garnish 91). For example, the muffler 10 has a flat shape (for example, a plate shape) (see FIG. 3). Also, for example, a muffler receiving portion 91U for receiving the housing 11 of the muffler 10 from the back side is recessed and formed in the main body portion 91H. The muffler 10 may project from the wall surface of the main body portion 91H toward the interior side, or may be received in the muffler receiving portion 91U and retracted from the wall surface of the main body portion 91H.

[0009] As shown in FIGS. 3 and 4, the housing 11 has a plurality of recesses 20 on its front surface and a communication passage 21 that connects the internal spaces of the recesses 20 to each other. The plurality of recesses 20 open to the front surface of the housing 11. The plurality of recesses 20 preferably open facing the same direction (in the example of this embodiment, the front-back direction of the housing 11). Also, in the example of this embodiment, the openings of the plurality of recesses 20 are arranged on the same plane of the housing 11. For example, the recess 20 has a shape with a uniform cross-sectional area from the opening to the bottom surface (for example, the internal space of the recess 20 is a cylindrical space. See FIGS. 3 and 5).

[0010] In the example of this embodiment, as these recesses 20, a large recess 20A and a small recess 20B with different opening areas are provided. The internal space of the large recess 20A and the internal space of the small recess 20B are connected by the communication passage 21. Therefore, in the example of this embodiment, the communication passage 21 is provided in the number corresponding to the number of the small recesses 20B. As shown in FIGS. 4 and 5, for example, a plurality of small recesses 20B are provided around one large recess 20A, and in the example of this embodiment, two small recesses 20B are provided. Specifically, in the silencer 10 of this embodiment, one large recess 20A is formed in the housing 11, and two small recesses 20B are arranged so as to sandwich the large recess 20A, and they are arranged side by side (for example, arranged linearly). Note that in the example of this embodiment, the silencer 10 has a long plate shape, and the recesses 20 are arranged in its longitudinal direction.

[0011] The opening area of ​​the large recess 20A is larger than the opening area of ​​the small recess 20B. Preferably, the opening area of ​​the large recess 20A is the same as the total area of ​​the openings of all the small recesses 20B that are connected to the large recess 20A by the connecting passage 21. Preferably, the opening area of ​​each small recess 20B is the same, and the depth of each small recess 20B is also the same. More preferably, each small recess 20B has the same volume and shape. In this embodiment, the opening area of ​​the large recess 20A is twice the opening area of ​​the small recess 20B, and the volume and shape of the small recesses 20B are the same. In this embodiment, since the height (depth) of the large recess 20A and the small recess 20B are the same, the total volume of the small recesses 20B is the same as the volume of the large recess 20A. Also, in this embodiment, the large recess 20A and the small recesses 20B are circular when viewed from the front side of the housing 11. In this disclosure, the term "identical (uniform)" is used to mean not only that the quantities being compared (e.g., length, area, volume, etc.) are strictly identical (uniform), but also that they are approximately identical (approximately uniform) (e.g., the difference between those quantities is within ±5%).

[0012] In this embodiment, the distance between the large recess 20A and each small recess 20B is the same, and each connecting passage 21 is the same length. When the large recess 20A and the small recess 20B are circular, as in this embodiment, it is preferable that the length of the connecting passage 21 is shorter than the difference in diameter between the large recess 20A and the small recess 20B. It is preferable that the width of the connecting passage 21 is narrower than the radius of the small recess 20B. It is also preferable that each connecting passage 21 has the same thickness. For example, the connecting passage 21 has a uniform thickness. In this embodiment, the connecting passage 21 extends in a straight line and is arranged to be the shortest path connecting the recesses 20 (arranged on the line segment connecting the centers of the large recess 20A and the small recess 20B).

[0013] Furthermore, in this embodiment, the connecting passage 21 is open to the front surface of the housing 11 (i.e., it has a groove shape that opens to the front surface of the housing 11), the depth of the connecting passage 21 (depth in the front-back direction of the housing 11) is the same as the recess 20 (large recess 20A, small recess 20B), and the bottom surfaces of the connecting passage 21 and the recess 20 are continuous without any step difference. Note that the depth of the connecting passage 21 can be made shallower or deeper than the recess 20.

[0014] As shown in Figures 4 and 6, in this embodiment, the housing 11 comprises a base plate 13, a surrounding wall portion 14 protruding from the base plate 13 to the front and back sides, and a bottom wall portion 15 that closes the internal space of the surrounding wall portion 14 from the back side. A recess 20 and a connecting passage 21 are formed in the portion enclosed by the surrounding wall portion 14, and the bottom surface of the recess 20 and the connecting passage 21 is formed by the bottom wall portion 15. For example, the base plate 13 has a plurality of positioning holes 13H, through which positioning projections 40T (see Figure 6) formed on the back side of the lid member 40 and positioning projections formed on the back side of the cover member 50 are inserted. The outer edge of the front side of the base plate 13 has a raised embankment portion 13D (see Figures 4 and 5) which is one step higher than its inner portion, and the embankment portion 13D is provided with positioning holes 13H through which the positioning projections of the cover member 50 are inserted.

[0015] The enclosure wall 14 has a ring portion 17 that forms each recess 20 on its inner side, and a pair of opposing walls 16 that are continuous with the ring portion 17 with a connecting passage 21 between them. The ring portion 17 that forms each recess 20 has an open shape in the portion facing the adjacent recess 20, and these open portions are connected by the connecting passage 21. The protruding tip of the ring portion 17 on the front side forms the opening edge of the recess 20.

[0016] As shown in Figures 3 and 7, the membrane member 30 closes the opening of the recess 20 from the front side. The membrane member 30 is fixed to the opening edge of the recess 20 of the housing 11. In the silencer 10, the vibrating membrane portion 31 of the membrane member 30 that closes the opening of the recess 20 is capable of vibrating in response to sound, and the vibration of the vibrating membrane portion 31 makes it possible to reduce sound. In this embodiment, the vibrating membrane portion 31 of the membrane member 30 is provided as a first vibrating membrane portion 31A that closes the opening of the large recess 20A, and a pair of second vibrating membrane portions 31B that each close the opening of the small recesses 20B.

[0017] In the housing 11 of this embodiment, the membrane member 30 closes not only the recesses 20 but also the communication passages 21 from the front side. By closing the recesses 20 and the communication passages 21 in this way, the inflow and outflow of gas between the inside and outside of the housing 11 is restricted. On the other hand, the communication passages 21 allow the inflow and outflow of gas between the large recess 20A and each small recess 20B. In this embodiment, a common membrane member 30 (see Figure 4) that is superimposed and fixed to the outer surface (front side) of the housing 11 completely closes the recesses 20 and the communication passages 21 from the front side.

[0018] In the silencer 10 of this embodiment, the lid member 40 is superimposed on and fixed to the housing 11, and the membrane member 30 is sandwiched between the lid member 40 and the housing 11 (specifically, the surrounding wall portion 14 that protrudes to the front side) (see Figure 7).

[0019] The lid member 40 has an opening 40K formed through it at a position corresponding to the opening of the recess 20 (for example, a position concentric with the opening) through which air can pass (see Figures 3 and 4). The size of the opening 40K of the lid member 40 is, for example, the size corresponding to the opening of the recess 20 of the housing 11 (for example, it is the same shape and size as each recess 20). In this embodiment, the lid member 40 (the opening 40K of the lid member 40) is provided such that only the vibrating membrane portion 31 (first vibrating membrane portion 31A and second vibrating membrane portion 31B) of the membrane member 30 is exposed (see Figure 8).

[0020] For example, as shown in Figure 6, surrounding projections 41 may be formed on the back surface of the lid member 40, enclosing multiple openings 40K (three openings 40K in the example of Figure 6). The surrounding projections 41 have a shape corresponding to the surrounding wall portion 14 of the housing 11 (for example, the same shape in a plan view), and are abutted together with the surrounding wall portion 14, sandwiching the membrane member 30 between them (see Figure 7).

[0021] As described above, the silencer 10 of this embodiment is provided with a cover member 50 on its front side (see Figures 2 and 3). The cover member 50 covers the housing 11, membrane member 30, and lid member 40 from the front side (indoor side). In this embodiment, the lid member 40 is smaller than the housing 11 (see Figure 5), and the cover member 50 is fixed to the housing 11 with its outer edge overlapping the outer edge (ridge portion 13D) of the housing 11 (see Figure 7).

[0022] The cover member 50 is breathable and positioned at a distance from the membrane member 30 so that the membrane member 30 (vibrating membrane portion 31) can vibrate due to sound (see Figure 9A). Preferably, the portion of the cover member 50 facing the vibrating membrane portion 31 through the opening 40K of the lid member 40 is breathable. For example, as shown in Figure 4, the cover member 50 has a plurality of through holes 50H formed therein to allow for breathability (note that the through holes 50H are not shown in Figure 2). For example, a large number of through holes 50H are densely provided in at least the portion of the cover member 50 facing the vibrating membrane portion 31.

[0023] The materials for the housing 11, lid member 40, and cover member 50 may be, for example, polyolefin resins such as polypropylene resin and polyethylene resin, thermoplastic resins such as ABS (acrylonitrile-butadiene-styrene copolymer) and polycarbonate resin, or thermosetting resins. For example, the housing 11, lid member 40, and cover member 50 may be made of resin (for example, resin molded products such as injection molded products) or of metal.

[0024] The housing 11 may be provided with an orifice that allows for the inflow and outflow of gas at an extremely small flow rate, thereby mitigating the pressure difference between the inside and outside of the housing 11. Alternatively, the housing 11 may be formed from a porous material with permeability that allows for the inflow and outflow of gas at an extremely small flow rate, thereby mitigating the pressure difference between the inside and outside of the housing 11. Examples of such porous materials include foams (for example, foams having an open-cell structure), and examples of foams include those made of polyurethane resin or polyolefin resins (for example, polypropylene resin or polyethylene resin).

[0025] The housing 11 may not be breathable. However, if the housing 11 does not allow air to pass from the back side into the recess 20, then when a pressure difference occurs inside and outside the housing 11 due to thermal expansion, for example, air cannot be ventilated through the housing 11. Therefore, if the housing 11 does not have a breathable structure, it is preferable that the membrane member 30 is breathable. This makes it possible to mitigate the pressure difference inside and outside the housing 11. For example, if the housing 11 and the membrane member 30 are non-breathable, when the air inside the recess 20 expands due to a rise in temperature, the membrane member 30 may bulge outwards, making it difficult for the membrane member 30 to vibrate. Therefore, from this point of view, it is preferable that the membrane member 30 or the housing 11 is breathable.

[0026] In this embodiment, the membrane member 30 is breathable. Examples of breathable membrane members 30 include nonwoven fabrics and fibrous sheets such as paper. In this embodiment, since the membrane member 30 is a wet nonwoven fabric, it is possible to have appropriate breathability while also providing a good sound-dampening effect due to vibration. The membrane member 30 is breathable, and its air permeability is 10 cm 3 / cm 2It is preferable that the value is less than or equal to s. Lowering the permeability of the membrane member 30 makes it easier to vibrate the vibrating membrane portion 31 of the membrane member 30. For example, the permeability of the membrane member 30 can be measured according to JIS L1096 Method A:2010. The thickness of the membrane member 30 (vibrating membrane portion 31) is not particularly limited as long as the membrane member 30 can vibrate in response to sound (especially noise). The basis weight of the membrane member 30 is set appropriately depending on the frequency band of the noise to be reduced.

[0027] As the wet-laid nonwoven fabric, for example, one composed of short fibers with a fiber length of less than 20 mm is preferred. Furthermore, as the wet-laid nonwoven fabric, it is preferable to include thermoplastic synthetic resin fibers (e.g., PET resin, etc.) and pulp fibers. If the membrane member 30 contains thermoplastic synthetic resin (e.g., PET resin, etc.), and the housing 11 is also constructed to include thermoplastic synthetic resin (e.g., polypropylene resin, etc.), the membrane member 30 can be fixed to the housing 11 by welding. If the fiber sheet constituting the membrane member 30 contains pulp fibers, it is possible to reduce the permeability of the membrane member 30.

[0028] In addition to fibers, other materials for the membrane member 30 include elastic materials such as EPDM (ethylene propylene rubber), TPU (thermoplastic polyurethane), and TPO (olefin-based thermoplastic elastomer). The membrane member 30 may not be permeable.

[0029] Next, the operation and effects of the silencer 10 of this embodiment will be described. As shown in Figure 9A, when sound S is input to the silencer 10 from the front side, for example, the sound S is input to the first vibrating membrane portion 31A (large recess 20A). At this time, the first vibrating membrane portion 31A vibrates at a frequency corresponding to the frequency of the sound S. Here, as described above, the large recess 20A, the small recesses 20B and the connecting passage 21 are closed by the housing 11 and the membrane member 30, and the inflow and outflow of gas into and out of the housing 11 is restricted. On the other hand, the inflow and outflow of gas between the large recess 20A and each small recess 20B is permitted by the connecting passage 21. Therefore, the sound S input to the large recess 20A is transmitted to each small recess 20B through the connecting passage 21. As a result, the second vibrating membrane portion 31B that closes each small recess 20B can be made to vibrate in accordance with the vibration of the first vibrating membrane portion 31A. At this time, as shown in Figure 9A, when the first vibrating membrane 31A bulges outwards towards the large recess 20A (inward) in response to the sound S input, the first vibrating membrane 31A conversely bulges outwards. That is, the second vibrating membrane 31B becomes capable of vibrating at the same frequency and in opposite phase as the first vibrating membrane 31A, and can output a sound S' at the same frequency and in opposite phase as the sound S input to the first vibrating membrane 31A (large recess 20A). As a result, the silencer 10 can cancel out and silence the sound S. In particular, as in the example of this embodiment, it is preferable that the opening area of ​​the opening of the large recess 20A is the same as the total opening area of ​​the openings of the small recesses 20B (total opening area), and it is even more preferable that the volume of the large recess 20A is the same as the total volume of the small recesses 20B. Doing so makes it possible to further enhance the sound-dampening effect.

[0030] Furthermore, when sound S is input to the silencer 10 from the front side, for example, as shown in Figure 9B, sound S may also be input to each second vibrating membrane section 31B (each small recess 20B). In this case, the second vibrating membrane section 31B vibrates at a frequency corresponding to the frequency of sound S. The sound S input to the small recess 20B is then transmitted to the large recess 20A through the connecting passage 21. This makes it possible to make the first vibrating membrane section 31A, which closes the large recess 20A, vibrate in response to the vibration of the second vibrating membrane section 31B. Then, it becomes possible to output sound S' from the first vibrating membrane section 31A at the same frequency as sound S but in the opposite phase, thereby canceling out and silenced sound S.

[0031] In this embodiment of the silencer 10, it is possible to silence sounds in a desired frequency range by adjusting the opening area and volume of the recess 20 in the housing 11, or by adjusting the thickness and material of the diaphragm 31, for the large recess 20A and the small recess 20B.

[0032] In recent years, the electrification of vehicles has reduced noise sources such as engines and transmissions, making various noises that were previously hidden more noticeable to occupants. In particular, wind noise (mid-to-high frequency noise) generated when the vehicle is in motion has become a bothersome noise. In response to this, the silencer 10 of this embodiment uses a lightweight material such as wet nonwoven fabric or paper for the membrane member 30, making it possible to effectively reduce noise in this frequency range. Furthermore, by positioning the silencer 10 near the occupant's ears in the interior material, it is possible to effectively reduce noise. In this embodiment, the silencer 10 is provided on the C-pillar garnish 91, so it is positioned near the ears of occupants sitting by the rear seats, making it possible to effectively reduce noise (for example, wind noise from the side windows 99 of the rear seats, etc.). Furthermore, if the silencer 10 is installed on the B-pillar garnish 92 (see Figure 17), which is an interior material that is superimposed on the B-pillar, it will be positioned near the ears of occupants sitting in the front seats, making it possible to effectively reduce noise (for example, wind noise from the side windows 99 of the front seats). Alternatively, for example, the silencer 10 may be installed on the A-pillar garnish, which is an interior material that is superimposed on the A-pillar. Since the silencer 10 of this embodiment does not require electricity, noise reduction can be achieved simply by installing it.

[0033] Vehicles on which the silencer 10 is installed include, for example, electric vehicles, plug-in hybrid vehicles, hybrid vehicles, and fuel cell vehicles.

[0034] [Second Embodiment] Figures 10 to 16 show the silencer 10 of the second embodiment. The silencer 10 of the second embodiment, like the silencer 10 of the first embodiment, is installed, for example, on the wall surface (for example, the wall surface facing the interior) of interior material (for example, pillar garnish, etc.) installed in the interior of a vehicle (for example, vehicle 100, etc.), for example, on the wall surface of the C pillar garnish 91.

[0035] The silencer 10 of this embodiment is the same as the first embodiment in that the housing 11, membrane member 30, lid member 40, and cover member 50 are stacked on top of each other (see Figures 11 and 12, etc.). The silencer 10 of this embodiment differs from the first embodiment in that the opening areas of the multiple recesses 20 of the housing 11 are the same (see Figures 12 to 14). In this example, a pair of sound-dampening sections 28 are provided, each consisting of a pair of recesses 20 (for example, circular recesses 20) with the same opening area and a linear passage 21 connecting them, with the communication direction of the passage 21 aligned and offset in the communication direction (see Figures 10 and 13). One recess 20 of one sound-dampening section 28 is positioned between a pair of recesses 20 of the other sound-dampening section 28 in the communication direction (see Figure 13). It is preferable that each connecting passage 21 has the same length, as shown in Figure 13.

[0036] For example, as shown in Figure 10, a pair of sound-dampening sections 28 may be arranged such that the communication direction of the connecting section 21 is inclined with respect to the vertical direction. In this case, the lower recess 20 of the upper sound-dampening section 28 may be in the same vertical position as the upper recess 20 of the other sound-dampening section 28 located below it.

[0037] Furthermore, the pair of sound-dampening sections 28 do not need to be offset in the direction of communication of the connecting passage 21, nor do they need to be aligned in the direction of communication of the connecting passage 21. Also, there may be only one sound-dampening section 28, or there may be three or more. In addition, the connecting passage 21 may have a shape other than a straight line (for example, a curved shape).

[0038] Other aspects of the silencer 10 of this embodiment are the same as those of the silencer 10 of the first embodiment described above. The silencer 10 of this embodiment also makes it possible to reduce noise by vibrating the vibrating membrane portion 31 of the membrane member 30, similar to the first embodiment (see Figures 16A and 16B).

[0039] In detail, for example, when sound S is input to one of the vibrating membrane parts 31 (upper vibrating membrane part 31) that closes one of the recesses of the sound-absorbing part 28 (upper recess 20 in Figure 16A), this upper vibrating membrane part 31 vibrates at a frequency corresponding to the frequency of sound S. Here, as described above, the upper recess 20, the other recess 20 (lower recess 20 in Figure 16A), and the connecting passage 21 are closed by the housing 11 and the membrane member 30, restricting the inflow and outflow of gas inside and outside the housing 11. On the other hand, the connecting passage 21 allows the inflow and outflow of gas between the recesses 20. Therefore, sound S input to the upper recess 20 is transmitted to the lower recess 20 through the connecting passage 21. This makes it possible to make the vibrating membrane part 31 (lower vibrating membrane part 31) that closes the lower recess 20 vibrate in accordance with the vibration of the upper vibrating membrane part 31. At this time, as shown in Figure 16A, when the upper vibrating membrane portion 31 bulges inward towards the recess 20 in response to the sound S input, the lower vibrating membrane portion 31 bulges outward. That is, the lower vibrating membrane portion 31 can vibrate at the same frequency and in opposite phase as the upper vibrating membrane portion 31, and can output a sound S' at the same frequency and in opposite phase as the sound S input to the upper vibrating membrane portion 31 (upper recess 20). As a result, the silencer 10 can cancel out and silence the sound S. In particular, as in the example of this embodiment, it is preferable that the opening area of ​​each recess 20 is the same, and it is even more preferable that the volume of each recess 20 is the same. Doing so makes it possible to further enhance the sound-dampening effect.

[0040] Furthermore, when sound S is input to the silencer 10 from the front side, for example, as shown in Figure 16B, sound S may also be input to the lower vibrating membrane 31. In this case, the lower vibrating membrane 31 vibrates at a frequency corresponding to the frequency of sound S. The sound S input to the lower recess 20 is then transmitted to the upper recess 20 through the connecting passage 21. This makes it possible to make the upper vibrating membrane 31, which closes the upper recess 20, vibrate in response to the vibration of the lower vibrating membrane 31. Then, it becomes possible to output sound S' from the lower vibrating membrane 31 at the same frequency as sound S but in the opposite phase, thereby canceling out and silenced sound S.

[0041] [Other embodiments] The shape of the silencer 10 is not limited to the shape of the embodiment described above. The silencer 10 may be, for example, a flat plate or a curved plate. In this case, it is sufficient that the multiple recesses 20 open facing the same side (front side). When the silencer 10 is a curved plate, it becomes easier to install the silencer 10 on the curved surface of the C-pillar garnish 91.

[0042] In the above embodiment, the opening of the recess 20 of the housing 11 was circular, but the opening is not limited to this and may be elliptical or polygonal (for example, a regular polygon). For example, it is preferable that the recesses 20 that are connected by the passage 21 have the same shape, but they may have different shapes.

[0043] In the above embodiment, each vibrating membrane portion 31 was provided on a common membrane member 30, but they may be provided on separate membrane bodies.

[0044] The muffler 10 installed in the vehicle is not limited to being installed on the pillar garnish, but may be installed on interior materials such as interior trim or roof liner 95, as shown in Figure 17. Examples of interior trim include door trim, quarter trim, and dashboard 96. The door trim may be, for example, the door trim 93 of the front door, the door trim 94 of the rear door, or the door trim of the back door. In addition, the base material (for example, the main body of the pillar garnish) of the interior material (for example, the pillar garnish) may be used as the housing 11. That is, the base material of the injection-molded interior material may be a base plate 13, and a recess 20 and a connecting passage 21 may be formed on it with an enclosure wall 14 to form the housing 11.

[0045] The interior material on which the silencer 10 is provided may be the interior material of a building. In the example of the above embodiment, the silencer 10 was provided on the interior material on a surface facing the interior, but the silencer 10 may also be provided on the interior material on a surface facing the exterior. Furthermore, the silencer 10 is not limited to being provided on an interior material. The silencer 10 may be provided, for example, on a seat component that constitutes at least a part of a seat provided in a vehicle or building. The silencer 10 may be provided, for example, on the side, top, or back of a headrest (seat component), on the top, side, or back of a seat back (seat component), on the side or front of a seat cushion (seat component), or on the side of an armrest, etc.

[0046] Furthermore, if the main body portion (for example, the main body portion 91H of the interior material) of the article (interior material, etc.) to which the silencer 10 is installed is a molded body integrally molded (for example, foam molded) with the housing 11 (i.e., if the housing 11 is an insert part integrally molded with the molded body), it is preferable that the housing 11 has a structure that prevents the resin of the molded body from passing into the recess 20 from the back side (for example, it is preferable that it has a structure that does not allow air to pass through). However, if the housing 11 has a structure that does not allow air to pass through, it becomes impossible to allow air to pass through the housing 11 when a pressure difference occurs inside and outside the housing 11 due to thermal expansion, for example. Therefore, if the housing 11 has a structure that does not allow air to pass through, it is preferable that the membrane member 30 has air permeability. This makes it possible to mitigate the pressure difference inside and outside the housing 11.

[0047] If the membrane member 30 is fixed so as to cover the recess 20 of the housing 11 (for example, if the membrane member 30 is fixed to the housing 11 by welding or the like), the silencer 10 does not need to be provided with a cover member 40. Also, the silencer 10 does not need to be provided with a cover member 50. If the silencer 10 does not have a cover member 50, a protective fence that covers the vibrating membrane 31 from the outside may be provided inside the opening 40K of the cover member 40. In this case, it is preferable that the protective fence be positioned at a distance so as not to come into contact with the vibrating vibrating membrane 31. [Examples]

[0048] The embodiments described above will be further explained below with reference to examples and comparative examples, but the silencers of this disclosure are not limited to the following examples. The silencer effect of the silencers of the examples and comparative examples was evaluated.

[0049] (1) Silencers of the Examples and Comparative Examples <Example 1> The silencer of Example 1 is the silencer 10 of the second embodiment shown in Figures 10 to 16. The silencer of Example 1 is provided with a pair of sound-absorbing parts 28 of the same shape and size in a housing 11, with the communication direction of the communication passage 21 aligned. The pair of recesses 20 of each sound-absorbing part 28 are circular when viewed from the front, with a diameter of 20 mm and a depth of 10 mm. The communication passage 21 has a width of 10 mm, a length of 10 mm, and a depth of 10 mm. The opening 40K of the lid member 40 is also circular, and the diameter of the opening 40K corresponding to the recess 20 is 18 mm. The housing 11 is made of polypropylene resin and is non-permeable. The membrane member 30 is a wet-laid nonwoven fabric containing PET fibers and pulp fibers (product name "IPP-40" manufactured by Nippon Paper Industries Co., Ltd.). The basis weight of the film member 30 is 40 g / m². 2 Therefore, the air permeability of the membrane member 30 is 8.5 cm 3 / cm 2 It is s.

[0050] In Example 1, as shown in Figures 1 and 18, the silencer 10 is installed on the wall surface facing the interior of the C-pillar garnish 91 at the right rear of the vehicle 100 (electric vehicle).

[0051] <Comparative Example 1> In Comparative Example 1, the silencer 10 is not installed on the vehicle 100 (electric vehicle).

[0052] (2) Evaluation method The noise level (sound pressure level) was evaluated for Example 1 and Comparative Example 1. Specifically, when the vehicle 100 (electric vehicle) was running at a steady speed of 100 km / h, the noise level (dB(A)) inside the vehicle was measured using a microphone placed at position P (see Figure 18), near the occupant's ear by the window, in the rightmost seat of the rear seats (the right rear seat in vehicle 100). This right rear seat is the seat closest to the right rear C-pillar garnish 91 equipped with the silencer 10 among all the seats in vehicle 100.

[0053] (3) Evaluation results As shown in Figure 19, in Example 1, in which the vehicle 100 is equipped with a silencer 10, it was confirmed that the noise level was significantly reduced for a wide range of frequencies from low to high compared to Comparative Example 1, in which the silencer 10 is not provided.

[0054] <Note> The following describes the features extracted from the above embodiments and examples, showing their effects as needed. For ease of understanding, corresponding configurations in the above embodiments will be indicated in parentheses as appropriate, but these features are not limited to the specific configurations indicated in parentheses.

[0055] For example, the following set of features can be considered to have been conceived with the objective of "providing a novel sound-dampening technology" in light of the background technology that "various sound-dampening technologies have been proposed conventionally (see, for example, Japanese Utility Model Registration No. 2502311 (paragraph

[0003] , etc.))" concerning "silencers and interior materials equipped therewith." Furthermore, there has been a long-standing need for the development of novel silencers and novel interior materials having silencers.

[0056] [Feature 1] A silencer comprising a housing having a plurality of recesses on its surface and a communication passage connecting the internal spaces of the recesses, and a membrane member that closes the openings of the plurality of recesses, The aforementioned membrane member is a breathable silencer.

[0057] [Feature 2] The sound-dampening device according to feature 1, wherein the membrane member is a wet nonwoven fabric.

[0058] [Feature 3] The sound-dampening device according to feature 2, wherein the wet-process nonwoven fabric comprises thermoplastic synthetic resin fibers and pulp fibers.

[0059] [Feature 4] The plurality of recesses include a first recess (large recess 20A) and a plurality of second recesses (small recesses 20B) that are each connected to the first recess by the connecting passage. The multiple connecting passages between the multiple second recesses and the multiple first recesses have the same length. The area of ​​the openings of the plurality of second recesses is the same. The silencer according to any one of the features 1 to 3, wherein the total area of ​​the openings of the plurality of second recesses is the same as the area of ​​the opening of the first recess.

[0060] [Feature 5] The silencer according to any one of features 1 to 3, wherein the plurality of recesses include a pair of recesses that are in communication with each other by the same length of the connecting passage and have the same area of ​​the opening.

[0061] [Feature 6] A sound-absorbing section is provided, comprising a pair of recesses having the same area, and a straight passage connecting them, with the passages aligned in the direction of communication and offset in the direction of communication. A silencer according to any one of features 1, 2, 3, or 5, wherein one of the recesses of one of the sound-dampening parts is positioned between a pair of recesses of the other sound-dampening part in the communication direction.

[0062] [Feature 7] The air permeability of the aforementioned membrane member is 10 cm 3 / cm 2 A silencer that is less than or equal to one of the characteristics described in any one of characteristics 1 through 6.

[0063] [Feature 8] A silencer according to any one of the features 1 to 7, comprising a cover member that covers the membrane member from a spaced-out position and has breathability.

[0064] [Feature 9] The silencer according to any one of features 1 to 8, wherein the housing is an insert part from which a foamed molded body is integrally molded, and the structure prevents the resin of the foamed molded body from passing into the recess from the back side.

[0065] [Feature 10] Interior materials provided in the interior of a vehicle (C-pillar garnish 91, B-pillar garnish 92, roof liner 95, door trim 93, 94), An interior material that incorporates a sound-dampening device, as described in any one of the features 1 through 9, into its wall surface.

[0066] [Feature 11] Interior materials as described in Feature 10, which are vehicle garnishes, trims, or roof liners.

[0067] Based on the above features, a novel sound-dampening technology is provided.

[0068] While this specification and drawings disclose specific examples of the technology included in the claims, the technology described in the claims is not limited to these specific examples, but also includes various modifications and changes to these examples, as well as parts of the examples taken individually. [Explanation of symbols]

[0069] 10 Silencer 11 Housing 13 Base Plate 13D Embankment 13H Positioning Hole 14 Enclosure 15 Bottom wall section 16 Opposing wall 17 Ring section 20 recesses 20A Large recess 20B Small recess 21 Communication path 28 Silencer 30 Membrane members 31 Vibrating membrane section 31A 1st vibrating membrane section 31B 2nd vibrating membrane section 40 Lid member 40K aperture 40T protrusion 41 Encircling thrust 50 Cover component 50H through hole 91 C-pillar garnish 91H Main Unit 91U Silencer receiver 92 B-pillar garnish 93 Door trim 94 Door trim 99 Side windows 100 vehicles

Claims

1. A silencer comprising a housing having a plurality of recesses on its surface and a communication passage connecting the internal spaces of the recesses, and a membrane member that closes the openings of the plurality of recesses, The aforementioned membrane member is a breathable silencer.

2. The sound-dampening device according to claim 1, wherein the membrane member is a wet nonwoven fabric.

3. The sound-dampening device according to claim 2, wherein the wet nonwoven fabric comprises thermoplastic synthetic resin fibers and pulp fibers.

4. The plurality of recesses include a first recess and a plurality of second recesses, each of which is connected to the first recess by the communication passage. The multiple connecting passages between the multiple second recesses and the multiple first recesses have the same length. The area of ​​the openings of the plurality of second recesses is the same. The silencer according to claim 1, wherein the total area of ​​the openings of the plurality of second recesses is the same as the area of ​​the opening of the first recess.

5. A sound-absorbing section is provided, comprising a pair of recesses having the same area as the opening and a straight connecting passage between them, with the connecting passages aligned in the direction of communication and offset in the direction of communication. The silencer according to claim 1, wherein one of the recesses of one of the sound-dampening parts is arranged between a pair of recesses of the other sound-dampening part in the communication direction.

6. The air permeability of the aforementioned membrane member is 10 cm ３ / cm ２ - The silencer according to claim 1, wherein s is less than or equal to s.

7. The silencer according to claim 1, comprising a cover member that covers the membrane member from a spaced-out position and is breathable.

8. Interior materials installed in the interior of a vehicle, An interior material having a silencer according to any one of claims 1 to 7 on its wall surface.

Images