Vehicle vent duct

Abstract

There is a need to develop technology that can reduce noise entering the vehicle cabin compared to conventional vent ducts. [Solution] One aspect of the invention is a vehicle vent duct equipped with a butterfly valve inside a duct member that can be attached to a vehicle body, and further equipped with a silencer fixed to the duct member and positioned opposite the butterfly valve, and forming an air passage between itself and the duct member, wherein the silencer is equipped with a plurality of recesses that open toward the butterfly valve, a communication passage that connects the plurality of recesses to each other, and a membrane member that closes the openings of the plurality of recesses.

Description

Technical Field

[0001] The present disclosure relates to a vehicle vent duct.

Background Art

[0002] Conventionally, a vent duct for releasing the pressure inside a vehicle cabin has been known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0020] to

[0022] ,

[0025] ,

[0037] , FIGS. 1 to 3, etc.)

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a need to develop a technology capable of reducing the noise entering the vehicle cabin with respect to conventional vent ducts.

Means for Solving the Problems

[0005] One aspect of the invention is a vehicle vent duct provided with a butterfly valve inside a duct member attachable to a vehicle body, the vehicle vent duct including a muffler fixed to the duct member and disposed opposite to the butterfly valve and forming a ventilation passage between the muffler and the duct member, the muffler including a plurality of recesses opening to the butterfly valve side, a communication passage communicating the plurality of recesses with each other, and a film member closing the openings of the plurality of recesses.

Brief Description of the Drawings

[0006] [Figure 1] FIG. 1 is a plan view of a vehicle provided with a vent duct [Figure 2] FIG. 2 is a side sectional view of the vent duct [Figure 3]Figure 3 is a side cross-sectional view of the vent duct when the butterfly valve is open. [Figure 4] Figure 4 is a perspective view of the vent duct. [Figure 5] Figure 5 is a front view of the vent duct. [Figure 6] Figure 6 is a side cross-sectional view of a silencer attached to a duct member. [Figure 7] Figure 7 is an exploded perspective view of the vent duct as seen from inside the vehicle. [Figure 8] Figure 8 is an exploded perspective view of the vent duct as seen from the outside of the vehicle. [Figure 9] Figure 9 is a plan view of the vent duct. [Figure 10] Figure 10 is a plan cross-sectional view of a silencer attached to a duct member. [Figure 11] Figure 11 is a front view of the duct component as seen from inside the vehicle. [Figure 12] Figure 12 is a side cross-sectional view of the diaphragm when sound is input to the first diaphragm. [Figure 13] Figure 13 is a side cross-sectional view of the diaphragm when sound is input to the second diaphragm. [Figure 14] Figure 14 is a graph showing the relationship between frequency and the average noise power in Example 1 and Comparative Example 1. [Modes for carrying out the invention]

[0007] [First Embodiment] Figures 1 and 2 show a vehicle vent duct 10 (hereinafter simply referred to as "vent duct 10") according to this embodiment. The vent duct 10 has a structure in which a butterfly valve 22 is provided inside a duct member 11 that can be attached to the vehicle body. The duct member 11 is provided with a vent opening 21 that discharges air from the passenger compartment of the vehicle 90 to the outside of the vehicle, and the vent opening 21 is opened and closed by the butterfly valve 22 (see Figures 2 and 3). The duct member 11 is arranged, for example, on the side of the vehicle 90 (for example, on both the left and right sides of the vehicle 90). In the following description, a vent duct 10 in which the duct member 11 is provided on the right side of the vehicle 90 will be described, but the same applies to a vent duct 10 in which the duct member 11 is provided on the left side of the vehicle 90. Examples of vehicles 90 include electric vehicles, plug-in hybrid vehicles, hybrid vehicles, fuel cell vehicles, and vehicles with internal combustion engines (such as gasoline engine vehicles).

[0008] For example, as shown in Figure 1, the vent opening 21 of the vent duct 10 opens on the side of the vehicle body panel 91 on the side of the vehicle 90, in the portion behind the rear wheels, in the portion covered by the rear bumper 92. In this embodiment, the duct member 11 has a peripheral wall portion 12 on which the vent opening 21 and butterfly valve 22 are provided inside (see Figures 2 and 4), and the peripheral wall portion 12 is fitted and fixed into a side opening 91K formed on the side of the vehicle body panel 91. In this embodiment, the peripheral wall portion 12 is cylindrical with a short axial length (specifically, rectangular) (see Figures 4 and 5).

[0009] As shown in Figure 2, the butterfly valve 22 is normally in a closed state (see Figure 2), but when the pressure inside the vehicle increases (due to a relative increase in pressure inside the vehicle relative to the pressure outside the vehicle), such as when the door is closed or the car air conditioner is operated, the butterfly valve 22 changes to an open state, allowing the pressure inside the vehicle to be released through the vent opening 21 (see Figure 3). In this embodiment, the butterfly valve 22 is flap-shaped and rotates around its upper end as the pivot point. In this embodiment, the opening edge of the vent opening 21 on which the butterfly valve 22 is superimposed is provided inside the peripheral wall portion 12 of the duct member 11. Since the opening edge is inclined upwards, when the pressure inside the vehicle is not high, the butterfly valve 22 closes the vent opening 21 by its own weight (see Figure 2).

[0010] For example, the vent opening 21 may be divided into multiple openings 21A by partitions 13 that span across opposing portions of the peripheral wall portion 12. In this embodiment, the partitions 13 are arranged in a grid pattern extending in the vertical and horizontal directions, and the multiple openings 21A are arranged two-dimensionally in the vertical and horizontal directions. For example, each opening 21A is rectangular in shape. In this embodiment, a butterfly valve 22 is provided to open and close each opening corresponding to each opening 21A, and the butterfly valve 22 is superimposed on the opening edge (partition 13) of the opening 21A.

[0011] The vent duct 10 is equipped with a silencer 50 fixed to the duct member 11 and positioned opposite the butterfly valve 22 (see Figure 2). The silencer 50 is fixed to the duct member 11 (see Figure 2). The silencer 50 forms an air passage R through which air can pass between itself and the duct member 11 (see Figures 4 and 5). The silencer 50 is equipped with a plurality of recesses 40 that open towards the butterfly valve 22, a communication passage 41 that connects the recesses 40, and a membrane member 30 that closes the openings of the recesses 40 (see Figure 2).

[0012] In the example of this embodiment, the muffler 50 is provided with a housing 43 in which a plurality of recesses 40 and a communication passage 41 are formed, and a film member 30 is held by the housing 43. In the muffler 50 of this embodiment, the housing 43 is fixed to the duct member 11 by a connecting arm 44. For example, the connecting arm 44 extends from a plurality of locations of the housing 43, and these connecting arms 44 are connected to the duct member 11. In the example of this embodiment, the housing 43 has a plate shape facing the butterfly valve 22 and has a rectangular shape in plan view (in the direction facing the butterfly valve 22) (see FIG. 5). And the connecting arm 44 extends from four locations of the housing 43 (both ends of a pair of long sides of the rectangular housing 43). For example, the connecting arm 44 extends to the side of the plate-shaped housing 43 and then bends toward the duct member 11 (for example, it bends at a substantially right angle). Also, in the example of this embodiment, the muffler 50 is provided with a frame portion 42 that connects the tip-side portions of these connecting arms 44 and is overlapped with the peripheral wall portion 12 of the duct member 11. Note that only one connecting arm 44 may be provided.

[0013] In the example of this embodiment, the housing 43 includes a first member 43A and a second member 43B that sandwich the film member 30 in the direction facing the housing 43 and the duct member 11 (see FIG. 6). In the example of this embodiment, both the first member 43A and the second member 43B have a plate shape (see FIGS. 7 and 8). The first member 43A is disposed on the side opposite to the duct member 11 with respect to the second member 43B and includes the plurality of recesses 40 and the communication passage 41 described above. The second member 43B is disposed closer to the duct member 11 than the first member 43A, and an opening 43K is formed at a position facing the recess 40 of the first member 43A. A fence portion 43F (for example, a lattice-shaped fence portion) for protecting the internal film member 30 may be formed in the opening 43K of the second member 43B (note that the fence portion 43F is not shown in the side cross-sectional view of the muffler 50 shown in FIGS. 2, 3, etc.). Also, the above-described connecting arm 44 extends from the second member 43B.

[0014] As shown in Figure 9, in this embodiment, a side recess 14 extending in the axial direction of the peripheral wall portion 12 of the duct member 11 is formed as a recess on the outer circumferential surface of the peripheral wall portion 12. The duct member 11 is also provided with a wedge-shaped retaining claw 15 that extends in the axial direction of the peripheral wall portion 12 and protrudes outward from the peripheral wall portion 12 as it approaches the side opposite the housing 43. The retaining claw 15 is elastically deformable so as to be received by the side recess 14 (see Figure 10). The retaining claw 15 is connected to the peripheral wall portion 12 by a connecting portion 16 that spans the width direction of the side recess 14 on the housing 43 side of the peripheral wall portion 12. An opening 17 is formed inside the connecting portion 16 at the housing 43 side end of the side recess 14. A connecting arm 44 is inserted into this opening 17 and received by the side recess 14, and is positioned between the peripheral wall portion 12 and the retaining claw 15 (connecting portion 16). This connects the connecting arm 44 to the duct member 11 (see Figure 9). It is preferable that the connecting arm 44 is inserted shallowly into the opening 17 so that the retaining claw 15 can be elastically deformed within the side recess 14 even when the connecting arm 44 is received in the side recess 14. That is, it is preferable that the tip of the connecting arm 44 overlaps only with the base end side (connecting part 16 side) of the retaining claw 15, and not with the tip side of the retaining claw 15. In this embodiment, the frame portion 42 described above abuts against the opening edge of the opening 17, acting as a stopper to prevent the connecting arm 44 from being inserted too deeply into the opening 17.

[0015] It is preferable that the multiple recesses 40 open in the same direction. In this embodiment, the openings of the multiple recesses 40 are arranged on the same plane of the housing 43. For example, the recesses 40 have a shape in which the cross-sectional area is uniform from the opening to the bottom surface (for example, the internal space of the recess 40 is a cylindrical space; see Figure 2).

[0016] In the example of this embodiment, as these recesses 40, large recesses 40A and small recesses 40B with different opening areas are provided. The internal space of the large recess 40A and the internal space of the small recess 40B are communicated by a communication passage 41. Therefore, in the example of this embodiment, the communication passages 41 are provided in the number corresponding to the number of the small recesses 40B. As shown in FIG. 8, for example, a plurality of small recesses 40B are provided around one large recess 40A, and in the example of this embodiment, two small recesses 40B are provided. Specifically, in the muffler 50 of this embodiment, one large recess 40A is formed in the housing 43 (the first member 43A), and two small recesses 40B are arranged so as to sandwich the large recess 40A, and they are arranged side by side (for example, arranged linearly). In the example of this embodiment, the muffler 50 has a long plate shape, and the recesses 40 are arranged in the longitudinal direction thereof.

[0017] The opening area of the large recess 40A is larger than the opening area of the small recess 40B. The opening area of the large recess 40A is preferably the same as the total opening area (total area) of all the small recesses 40B communicated with the large recess 40A by the communication passage 41. Also, the opening areas of the respective small recesses 40B are preferably the same, and the depths of the respective small recesses 40B are also preferably the same. More preferably, the volumes and shapes of the respective small recesses 40B are the same. In the example of this embodiment, the opening area of the opening of the large recess 40A is twice the opening area of the opening of the small recess 40B, and the volumes and shapes of the small recesses 40B are the same. In the example of this embodiment, since the heights (depths) of the large recess 40A and the small recesses 40B are the same, the total volume of the small recesses 40B is the same as the volume of the large recess 40A. Also, in the example of this embodiment, the large recess 40A and the small recesses 40B are circular when viewed from the front side of the housing 43 (the duct member 11 side). In the present disclosure, being the same (uniform) means, of course, including being exactly the same (uniform) for the quantities to be compared (for example, length, area, volume, etc.), and also including being approximately the same (approximately uniform) (for example, the difference between those quantities is within the range of ±5%).

[0018] In this embodiment, the distance between the large recess 40A and each small recess 40B is the same, and each connecting passage 41 is the same length. When the large recess 40A and the small recess 40B are circular, as in this embodiment, it is preferable that the length of the connecting passage 41 is shorter than the difference in diameter between the large recess 40A and the small recess 40B. It is preferable that the width of the connecting passage 41 is narrower than the radius of the small recess 40B. It is also preferable that each connecting passage 41 has the same thickness. For example, the connecting passage 41 has a uniform thickness. In this embodiment, the connecting passage 41 extends in a straight line and is arranged to be the shortest path connecting the recesses 40 (arranged on the line segment connecting the centers of the large recess 40A and the small recess 40B).

[0019] Furthermore, in this embodiment, the connecting passage 41 is open to the front surface (the side of the duct member 11) of the first member 43A of the housing 43 (i.e., it has a groove shape that opens to the front surface of the housing 43), the depth of the connecting passage 41 (the depth of the housing 43 in the front-back direction) is the same as the recess 40 (large recess 40A, small recess 40B), and the bottom surfaces of the connecting passage 41 and the recess 40 are continuous without any step difference. Note that the depth of the connecting passage 41 can be made shallower or deeper than the recess 40.

[0020] As shown in Figures 7 and 8, in this embodiment, the first member 43A comprises a base plate 43P, an enclosure portion 43H protruding from the front and back sides of the base plate 43P, and a bottom wall portion 43T that closes the internal space of the enclosure portion 43H from the back side. A recess 40 and a connecting passage 41 are formed in the portion enclosed by the enclosure portion 43H, and the bottom surface of the recess 40 and the connecting passage 41 is formed by the bottom wall portion 43T. For example, the base plate 43P has a plurality of positioning holes 43J, and positioning projections 43Y (see Figure 7) formed on the back side (the side opposite to the duct member 11) of the second member 43B are inserted through these positioning holes 43J.

[0021] The enclosure wall portion 43H has a ring portion 47 that forms each recess 40 on its inner side, and a pair of opposing walls 46 that are continuous with the ring portion 47 with a connecting passage 41 between them. The ring portion 47 that forms each recess 40 has an open shape in the portion facing the adjacent recess 40, and these open portions are connected by the connecting passage 41. The protruding tip of the ring portion 47 on the front side forms the opening edge of the recess 40.

[0022] As shown in Figures 3 and 8, the membrane member 30 closes the opening of the recess 40 from the front side. The membrane member 30 is fixed to the opening edge of the recess 40 of the first member 43A. In the silencer 50, the vibrating membrane portion 31 of the membrane member 30 that closes the opening of the recess 40 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 40A, and a pair of second vibrating membrane portions 31B that each close the opening of the small recesses 40B.

[0023] In the housing 43 of this embodiment, the membrane member 30 closes not only the recesses 40 but also the communication passages 41 from the front side. By closing the recesses 40 and the communication passages 41 in this way, the inflow and outflow of gas into and out of the housing 43 is restricted. On the other hand, the communication passages 41 allow the inflow and outflow of gas between the large recess 40A and each small recess 40B. In this embodiment, a common (single) membrane member 30 (see Figure 2), which is superimposed and fixed on the outer surface (front side) of the first member 43A, completely closes the recesses 40 and the communication passages 41 from the front side.

[0024] In the silencer 50 of this embodiment, the second member 43B is superimposed on and fixed to the first member 43A, and the membrane member 30 is sandwiched between the second member 43B and the first member 43A (specifically, the surrounding wall portion 43H that protrudes to the front side) (see Figure 2).

[0025] The second member 43B has an opening 43K through which air can pass, formed at a position corresponding to the opening of the recess 40 (for example, a position concentric with the opening) (see Figures 3 and 8). The size of the opening 43K in the second member 43B is, for example, the size corresponding to the opening of the recess 40 formed in the first member 43A (for example, it is the same shape and size as each recess 40). In this embodiment, the second member 43B (the opening 43K of the second member 43B) 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 Figures 3 and 8).

[0026] For example, as shown in Figure 7, a surrounding projection 48 may be formed on the back surface of the second member 43B, surrounding a plurality of openings 43K (three openings 43K in the example of Figure 7). The surrounding projection 48 has a shape corresponding to the surrounding wall portion 43H of the first member 43A (for example, the same shape in a plan view), and is abutted against the surrounding wall portion 43H as a whole, sandwiching the membrane member 30 between the surrounding wall portion 43H and the surrounding wall portion 43H. The fence portion 43F is positioned at a distance from the membrane member 30 so that the membrane member 30 (vibrating membrane portion 31) can vibrate due to sound.

[0027] As shown in Figure 11, in this embodiment, the total area of ​​the vent opening 21 of the duct member 11 projected onto a flat surface (virtual flat surface) including the membrane member 30 is larger than the total area of ​​the outer shape of the housing 43 on that flat surface. That is, the vent opening 21 faces the housing 43 and, when viewed from that opposing direction, protrudes from the housing 43. With this configuration, it is possible to suppress obstruction of the airflow exhausted from the vent opening 21 by the housing 43. Note that the vent opening 21 (opening 21A) in Figure 11 is shown in gray. The outer shape of the housing 43 is shown by a dashed line.

[0028] The material of the first member 43A and the second member 43B may be, for example, a polyolefin resin such as polypropylene resin or polyethylene resin, a thermoplastic resin such as ABS (acrylonitrile-butadiene-styrene copolymer) or polycarbonate resin, or a thermosetting resin. For example, the first member 43A and the second member 43B may be made of resin (for example, a resin molded product such as an injection molded product) or of metal.

[0029] The first member 43A 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 inside and outside the first member 43A. Alternatively, the first member 43A may be formed from a porous body with permeability that allows for the inflow and outflow of gas at an extremely small flow rate, thereby mitigating the pressure difference inside and outside the first member 43A. Examples of such porous bodies 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).

[0030] Examples of 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 be non-permeable or permeable, such as a fiber sheet, as long as it can vibrate in response to sound.

[0031] Next, the operation and effects of the silencer 50 of this embodiment will be described. As shown in Figure 12, when sound S is input to the silencer 50 from the front side (duct member 11 side), for example, the sound S is input to the first vibrating membrane 31A (large recess 40A). At this time, the first vibrating membrane 31A vibrates at a frequency corresponding to the frequency of the sound S. Here, as described above, the large recess 40A, the small recesses 40B and the connecting passage 41 are closed by the first member 43A and the membrane member 30, and the inflow and outflow of gas inside and outside the first member 43A is restricted. On the other hand, the inflow and outflow of gas between the large recess 40A and each small recess 40B is permitted by the connecting passage 41. Therefore, the sound S input to the large recess 40A is transmitted to each small recess 40B through the connecting passage 41. As a result, the second vibrating membrane 31B that closes each small recess 40B can be made to vibrate in accordance with the vibration of the first vibrating membrane 31A. At this time, as shown in Figure 12, when the first vibrating membrane 31A bulges outwards towards the large recess 40A (inward) in response to the sound S input, the second vibrating membrane 31B 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 40A). As a result, the silencer 50 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 40A is the same as the total opening area of ​​the openings of the small recesses 40B (total opening area), and it is even more preferable that the volume of the large recess 40A is the same as the total volume of the small recesses 40B. Doing so makes it possible to further enhance the sound-dampening effect.

[0032] Furthermore, when sound S is input to the silencer 50 from the front side, for example, as shown in Figure 13, sound S may also be input to each second vibrating membrane section 31B (each small recess 40B). 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 40B is then transmitted to the large recess 40A through the connecting passage 41. This makes it possible to make the first vibrating membrane section 31A, which closes the large recess 40A, 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.

[0033] In this embodiment of the silencer 50, by adjusting the opening area and volume of the recess 40 of the first member 43A, or by adjusting the thickness and material of the vibrating membrane 31, it is possible to silence sounds in a desired frequency range.

[0034] In recent years, the electrification of vehicles has reduced noise sources such as engines and transmissions, making various previously hidden noises more noticeable to occupants. In particular, the noise generated when the butterfly valve 22 opens and the vent opening 21 is released during vehicle operation has become a noticeable noise. In contrast, the vent duct 10 of this embodiment has a silencer 50 positioned opposite the vent opening 21, making it possible to effectively reduce noise. Although Figures 12 and 13 show the butterfly valve 22 in the open position, noise can also be reduced when the butterfly valve 22 is closed by the vibration of the membrane member 30 of the silencer 50.

[0035] [Other embodiments] In the above embodiment, the opening of the recess 40 of the housing 43 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 40 that are connected by the passage 41 are similar in shape, but they may be different in shape.

[0036] 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 members. [Examples]

[0037] The embodiments described above will be further explained below with reference to examples and comparative examples, but the vent ducts of this disclosure are not limited to the following examples. The sound-dampening effect of the vent ducts of the examples and comparative examples was evaluated.

[0038] (1) Silencers of the Examples and Comparative Examples <Example 1> The vent duct of Example 1 is a vent duct 10 similar to that of the First Embodiment shown in Figures 2-12, and is equipped with a silencer 50. The first member 43A of the housing 43 is provided with one large recess 40A and two small recesses 40B, which are circular when viewed from the front. The diameter of the large recess 40A is 41 mm, the diameter of each small recess 40B is 29 mm, and the depth of these recesses 40 is 10 mm. The large recess 40A and the small recesses 40B are arranged so that their centers are aligned in a straight line at equal intervals. The connecting passage 41 has a width of 10 mm, a length of 10 mm, and a depth of 10 mm. The opening 43K of the second member 43B is also circular, with the diameter of the opening 43K corresponding to the large recess 40A being 42 mm and the diameter of the opening 43K corresponding to the small recesses 40B being 30 mm, but there is no fence section 43F. The housing 43 is made of polypropylene resin and is non-permeable. The membrane member 30 is made of EPDM with a thickness of 0.3 mm and is non-permeable.

[0039] <Comparative Example 1> The vent duct of Comparative Example 1 differs from that of Example 1 in that it does not have a silencer 50. Otherwise, it is the same as that of Example 1.

[0040] (2) Evaluation method For Example 1 and Comparative Example 1, the average power value of the noise was evaluated. Specifically, with the butterfly valve 22 of the vent duct fully open, sound was introduced into the vent duct from the outside of the stationary vehicle 90. Then, as shown in Figures 2, 5, and 9, the noise was measured with a microphone at five points P1 to P5, located 200 mm away from the silencer 50, and the average power value (dB) was calculated. Positions P1 and P2 are located on either side of the silencer 50 in the vertical direction. Position P3 is directly facing the center of the first vibrating membrane 31A from the inside of the vehicle. Positions P4 and P5 are located on either side of the silencer 50 in the front-rear direction of the vehicle 90.

[0041] (3) Evaluation results Figure 14 shows the average power (dB) of the noise at positions P1 to P5. As shown in Figure 14, it was confirmed that the vent duct 10 of Example 1, which is equipped with a silencer 50, showed a significant reduction in noise levels over a wide range of frequencies compared to the vent duct of Comparative Example 1, which is not equipped with a silencer 50.

[0042] <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.

[0043] For example, the following set of features, relating to vehicle vent ducts, can be considered to have been conceived with the background technology that "vent ducts for releasing pressure inside the vehicle interior have been known for some time (see, for example, Japanese Patent Application Publication No. 2000-127750 (paragraphs

[0020] to

[0022] ,

[0025] ,

[0037] , Figures 1 to 3, etc.))" and the challenge that "there is a need to develop a technology that can reduce noise entering the vehicle interior compared to conventional vent ducts." Furthermore, there has been a demand for novel vent ducts and novel silencers.

[0044] [Feature 1] A vehicle vent duct equipped with a butterfly valve inside a duct member that can be attached to the vehicle body, The duct member is fixed to the duct member and positioned opposite the butterfly valve, and a silencer is provided which forms an air passage between the duct member and the silencer. The silencer includes, Multiple recesses opening on the butterfly valve side, A communication passage connecting multiple recesses, A vehicle vent duct comprising a membrane member that closes the openings of a plurality of recesses.

[0045] [Feature 2] The plurality of recesses of the silencer include a first recess and a plurality of second recesses, each connected to the first recess by a plurality of connecting passages of the same length. The vehicle vent duct according to feature 1, wherein the plurality of second recesses have the same opening area, and the total opening area of ​​the plurality of second recesses is the same as the opening area of ​​the first recess.

[0046] [Feature 3] The silencer has a housing in which a plurality of recesses and communication passages are formed and which holds the membrane member. The duct member has a vent opening that is opened and closed by the butterfly valve, The vehicle vent duct according to feature 1 or 2, wherein the total area of ​​the vent opening projected onto the flat surface including the membrane member is greater than the total area of ​​the outer shape of the housing on the flat surface including the membrane member.

[0047] [Feature 4] The vehicle vent duct according to feature 1, wherein the silencer includes a housing having a plurality of recesses and communication passages and holding the membrane member, and a plurality of connecting arms extending from a plurality of locations in the housing and connected to the duct member.

[0048] [Feature 5] The duct member includes, The outer surface of the cylindrical portion (circumferential wall portion 12) is recessed, and the side recess extends in the axial direction of the cylindrical portion, The retaining claw is provided, which has a wedge shape extending in the axial direction of the cylindrical portion and protruding outward from the cylindrical portion as it is toward the opposite side from the housing, and is elastically deformable so as to be received in the side recess. The retaining claw is connected to the cylindrical portion by a connecting portion that extends in the width direction of the side recess on the housing side, and an opening is formed inside the connecting portion at the housing side end of the side recess. The vehicle vent duct according to feature 4, wherein the connecting arm is inserted into the opening in the side recess and connected to the duct member.

[0049] Based on the above features, it becomes possible to reduce the noise entering the vehicle cabin.

[0050] 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]

[0051] 10. Vehicle vent ducts (vent ducts) 11 Duct components 12 Peripheral wall section 13 Partition 14 Side recess 15 Retaining claws 16 Connection part 17 Aperture 21 Vent opening 21A opening 22 Butterfly valve 31 Vibrating membrane section 31A 1st vibrating membrane section 31B 2nd vibrating membrane section 40 recess 40A Large recess 40B Small recess 41 Communication path 43 Housing 43A First component 43B Second Member 43F Fence Section 43H Enclosure 43J Positioning hole 43K aperture 43P Base Plate 43T bottom wall 43Y Positioning projection 44 connecting arms 46 Opposing wall 47 Ring section 48 Encircling thrust 50 Silencer 30 Membrane components 90 vehicles 91 Body Panel 91K side opening 92 Rear Bumper R ventilation channel S sound

Claims

1. A vehicle vent duct equipped with a butterfly valve inside a duct member that can be attached to the vehicle body, The duct member is fixed to the duct member and positioned opposite the butterfly valve, and a silencer is provided which forms an air passage between the duct member and the silencer. The silencer includes, Multiple recesses opening on the butterfly valve side, A communication passage connecting multiple recesses, A vehicle vent duct comprising a membrane member that closes the openings of a plurality of recesses.

2. The plurality of recesses of the silencer include a first recess and a plurality of second recesses, each connected to the first recess by a plurality of connecting passages of the same length. The vehicle vent duct according to claim 1, wherein the plurality of second recesses have the same opening area, and the total opening area of ​​the plurality of second recesses is the same as the opening area of ​​the first recess.

3. The silencer has a housing in which a plurality of recesses and communication passages are formed and which holds the membrane member. The duct member has a vent opening that is opened and closed by the butterfly valve, The vehicle vent duct according to claim 1, wherein the total area of ​​the vent opening projected onto the flat surface including the membrane member is greater than the total area of ​​the outer shape of the housing on the flat surface including the membrane member.

4. The vehicle vent duct according to claim 1, wherein the silencer includes a housing having a plurality of recesses and communication passages and holding the membrane member, and a plurality of connecting arms extending from a plurality of locations in the housing and connected to the duct member.

5. The duct member includes, The outer surface of the cylindrical portion is recessed, and the side recess extends in the axial direction of the cylindrical portion, The retaining claw is provided, which has a wedge shape extending in the axial direction of the cylindrical portion and protruding outward from the cylindrical portion as it is toward the opposite side from the housing, and is elastically deformable so as to be received in the side recess. The retaining claw is connected to the cylindrical portion on the housing side by a connecting portion that extends in the width direction of the side recess, and an opening is formed inside the connecting portion at the housing side end of the side recess. The vehicle vent duct according to claim 4, wherein the connecting arm is inserted into the opening in the side recess and connected to the duct member.

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