WO2021153193A1

WO2021153193A1 - Duct

Info

Publication number: WO2021153193A1
Application number: PCT/JP2021/000461
Authority: WO
Inventors: 龍介木村; 裕章森川
Original assignee: トヨタ紡織株式会社
Priority date: 2020-01-31
Filing date: 2021-01-08
Publication date: 2021-08-05
Also published as: JP2021121733A

Abstract

A duct (10) has a duct body (11) through which gas can pass. The duct body (11) is internally provided with a plurality of partition walls (12A to 12D) disposed midway along an extending direction of the duct body (11) and extending in the extending direction. Inside the duct body (11), an inner duct (14) through which gas can pass is defined and formed by the plurality of partition walls (12A to 12D).

Description

duct

This disclosure relates to a duct through which gas passes.

Patent Document 1 describes an intake duct that has a tubular shape and allows intake air of an internal combustion engine to pass through the inside.

Japanese Unexamined Patent Publication No. 2016-125379

In a duct through which gas passes, such as the above intake duct, noise generated when gas passes becomes a problem.

The purpose of this disclosure is to provide a duct that can suppress the generation of noise.

The duct for solving the above-mentioned problems has an annular cross-sectional shape, has a duct main body through which gas can pass, and has a plurality of partition walls extending in the extending direction of the duct main body, and the plurality of partitions. The walls are arranged in a direction intersecting the extension direction at intervals from each other, and are provided in a non-dispersed portion inside the duct body that does not have an expander, and the walls are provided in the non-dispersed portion of the duct body. An internal duct through which gas can pass is formed in the middle of the extension direction.

According to the above configuration, when a gas passes through the duct body and the duct having the internal duct, a resonance phenomenon can be generated inside the internal duct. Then, by interfering the sound wave of the resonance frequency generated in the internal duct with the sound wave passing through the portion other than the internal duct in the duct, the sound wave of each frequency passing through the duct is of the resonance frequency. The sound pressure level of sound waves can be lowered. According to the above configuration, noise generation can be suppressed in this way.

FIG. 1A is a side sectional view of the duct of the first embodiment, and FIG. 1B is a side view of the duct. 2A and 2B are explanatory views for explaining the operation of the duct. A side sectional view of the duct of the second embodiment. FIG. 3 is a cross-sectional view taken along the line 4-4 of FIG. Explanatory drawing for explaining the operation of the duct. A side sectional view of the curved portion of the duct and its surroundings.

(First Embodiment)
Hereinafter, the duct 10 of the first embodiment will be described.

As shown in FIGS. 1A and 1B, the duct 10 includes a cylindrical duct main body 11, a cylindrical inner pipe portion 12 provided inside the duct main body 11, and the duct main body 11 and the inner pipe portion 12. It has a plurality of connection wall portions 13 for connecting the above. In the duct 10, the duct main body 11, the inner pipe portion 12, and the connecting wall portion 13 are integrally formed of a hard synthetic resin material. The duct 10 is an intake duct that forms a part of the intake passage of the internal combustion engine, and is configured so that the intake air of the internal combustion engine passes through the inside.

The duct body 11 has the same cross-sectional shape in the direction orthogonal to the center line Lc1 in each part in the extension direction. As a result, in the present embodiment, the entire duct body 11 is a non-dispersed portion that does not have an expander (specifically, an air cleaner or a surge tank).

The inner pipe portion 12 has a cylindrical shape thinner than the duct main body 11. The inner pipe portion 12 is provided inside the duct main body 11 in such a manner that the center line of the inner pipe portion 12 and the center line Lc1 of the duct main body 11 coincide with each other. The length L1 of the inner pipe portion 12 in the extending direction is half (L1 × 2 = L2) of the length L2 of the duct main body 11 in the extending direction. The inner pipe portion 12 is arranged in the middle of the duct main body 11 in the extension direction, specifically in the center of the extension direction. Specifically, the inner pipe portion 12 is provided inside the duct main body 11 in such a manner that the position corresponding to the center in the extension direction of the duct main body 11 and the position corresponding to the center in the extension direction of the inner pipe portion 12 coincide with each other. There is. As shown in FIG. 1B, the inner pipe portion 12 includes a first wall portion 12A, a second wall portion 12B, a third wall portion 12C, and a fourth wall portion 12D. The first wall portion 12A and the second wall portion 12B are located so as to be arranged at intervals from each other in a direction intersecting the extending direction of the duct main body 11. Similarly, the third wall portion 12C and the fourth wall portion 12D are positioned so as to be arranged at intervals from each other in a direction intersecting the extending direction of the duct main body 11. The wall portions 12A to 12D extend in the extending direction of the duct main body 11 that coincides with the extending direction of the inner pipe portion 12. Due to these wall portions 12A to 12D, the inner pipe portion 12 is formed in a cylindrical shape thinner than the duct main body 11. Specifically, the wall portions 12A to 12D are integrally formed with each other so as to form a cylindrical shape. That is, the inner tube portion 12 is formed as a one-piece product. In this embodiment, the inside of the inner pipe portion 12 corresponds to the inner duct 14. The inner pipe portion 12, specifically, the wall portions 12A to 12D of the inner pipe portion 12 correspond to a plurality of partition walls forming the inner duct 14 in the middle in the extending direction of the duct main body 11.

Each connecting wall portion 13 has a flat plate shape extending in the extending direction and the radial direction of the duct main body 11. The plurality of connecting wall portions 13 are arranged so as to be arranged at equal intervals in the circumferential direction of the duct main body 11. In this embodiment, four connecting wall portions 13 are provided. Each connecting wall portion 13 extends in a manner of connecting the inner surface of the duct main body 11 and the outer surface of the inner pipe portion 12. The duct 10 of the present embodiment has a double pipe structure in which the inner pipe portion 12 is supported inside the duct main body 11 via these connecting wall portions 13.

Hereinafter, the operation of the duct 10 of the present embodiment will be described.

As shown in FIG. 2A, the duct 10 has a first end 15 (left end in FIG. 2A) and a second end 16 (right end in FIG. 2A). Inside the duct 10, the intake air of the internal combustion engine flows from the first end portion 15 to the second end portion 16. Along with this, the sound wave that causes the intake noise travels inside the duct 10 in the direction opposite to the flow of the intake air, specifically from the second end 16 to the first end 15. Become.

As shown in FIG. 2B, in the duct 10 of the present embodiment, since the inner pipe portion 12 is provided inside the duct main body 11, a resonance phenomenon is generated inside the inner pipe portion 12 (internal duct 14). be able to. Then, a sound wave having a resonance frequency (specifically, a primary, secondary, ... Nth resonance frequency) generated in the internal duct 14 and a sound wave passing through a portion other than the internal duct 14 in the duct 10 (FIG. 2A). By interfering with each other, the sound pressure level of the sound wave of the resonance frequency among the sound waves of each frequency passing through the duct 10 can be lowered.

In the duct 10 of the present embodiment, the length L1 of the inner pipe portion 12 in the extension direction (see FIG. 1A) is half of the length L2 of the duct main body 11 in the extension direction, and the inner pipe portion 12 is the duct. It is arranged at the center of the main body 11 in the extending direction. Therefore, in the portion corresponding to both ends of the internal duct 14 in the extending direction (the portion indicated by the arrow C in FIG. 2B), that is, the internal duct at the boundary portion between the internal duct 14 and the portion other than the internal duct 14 in the duct main body 11. The node of the standing wave Fi of the sound wave of the resonance frequency in 14 and the antinode of the standing wave Fb (FIG. 2A) of the sound wave of the secondary resonance frequency in the portion other than the internal duct 14 in the duct 10 come to coincide with each other. As a result, the sound wave of the resonance frequency in the internal duct 14 and the sound wave of the secondary resonance frequency in the duct body 11 interfere with each other in the vicinity of the boundary portion, so that the sound wave of the sound wave of the secondary resonance frequency in the duct body 11 interferes. The pressure level can be kept low.

According to the duct 10 of the present embodiment, the generation of intake noise can be suppressed in this way.

As described above, according to the present embodiment, the effects described below can be obtained.

(1) The internal duct 14 is partitioned in the middle of the extension direction of the duct main body 11 inside the cylindrical duct main body 11. Therefore, the generation of intake noise can be suppressed.

(2) By forming the duct 10 into a double pipe structure including a duct main body 11 and an inner pipe portion 12 inside the duct main body 11, the inside of the inner pipe portion 12 can be made into an internal duct 14.

(Second Embodiment)
Hereinafter, the duct 20 of the second embodiment will be described.

As shown in FIGS. 3 and 4, the duct 20 has a cylindrical duct main body 21 and two

ribs

22 and 23 provided inside the duct main body 21. In the duct 20, the duct body 21 and the

ribs

22 and 23 are integrally formed of a hard synthetic resin material. The duct 20 is an intake duct that forms a part of the intake passage of the internal combustion engine, and is configured so that the intake air of the internal combustion engine passes through the inside.

The duct body 21 has the same cross section in the direction orthogonal to the center line Lc2 in each part in the extension direction. As a result, in the present embodiment, the entire duct body 21 is a non-dispersed portion that does not have an expander (specifically, an air cleaner or a surge tank). The duct main body 21 has a curved portion 24 in an intermediate portion in the extending direction. The curved portion 24 is curved and extends in an arcuate manner. The duct main body 21 is extended so as to bend 90 degrees at the curved portion 24.

The two

ribs

22 and 23 are arranged in the middle of the extension direction of the duct main body 21, specifically inside the curved portion 24. Each of the

ribs

22 and 23 has a curved plate shape that is curved and extends along the center line Lc2 of the duct main body 11 in a manner of connecting the opposing portions on the inner surface of the curved portion 24. The

ribs

22 and 23 are arranged inside the curved portion 24 of the duct main body 21 so as to be arranged from the inside to the outside in the bending direction of the curved portion 24. The

ribs

22 and 23 extend so as to partition the inside of the duct body 11 into an inner portion and an outer portion in the bending direction.

In the duct 20 of the present embodiment, a pair of

internal ducts

25 and 26 are partitioned inside the duct main body 21 by the inner surface of the duct main body 21 and the

ribs

22 and 23. Specifically, the outer inner duct 25 is partitioned by the rib 22 on the outer side in the bending direction and the portion of the duct body 21 on the outer side in the bending direction with respect to the rib 22. Further, the inner duct 26 is partitioned by the rib 23 on the inner side in the bending direction and the portion on the inner side of the duct main body 21 in the bending direction. In the present embodiment, the

ribs

22 and 23 correspond to a plurality of partition walls forming the

internal ducts

25 and 26 in the middle of the duct main body 21 in the extending direction.

Hereinafter, the operation of the duct 20 of the present embodiment will be described.

As shown in FIGS. 3 and 5, the duct 20 has a first end 27 (the left end in FIG. 5) and a second end 28 (the right end in FIG. 5). Inside the duct 20, the intake air of the internal combustion engine flows from the first end 27 to the second end 28. Along with this, the sound wave that causes the intake noise travels inside the duct 20 in the direction opposite to the flow of the intake air, specifically from the second end 28 to the first end 27. Note that FIG. 5 shows a duct 20 in a state in which the entire duct is linearly extended in order to facilitate understanding of the traveling mode of the sound wave.

As shown in FIG. 5, in the duct 20 of the present embodiment, since the two

internal ducts

25 and 26 are partitioned inside the duct main body 21, a resonance phenomenon is generated in the

internal ducts

25 and 26. Can be done. Then, the sound waves of the resonance frequencies (specifically, the primary, secondary, ... Nth-order resonance frequencies) generated in the

internal ducts

25 and 26 and the sound waves passing through the parts other than the

internal ducts

25 and 26 in the duct 20 By interfering with each other, the sound pressure level of the sound wave of the resonance frequency among the sound waves of each frequency passing through the duct 20 can be lowered.

As shown in FIGS. 3 and 5, in the duct 20 of the present embodiment, the length of the rib 22 that defines the length of the outer inner duct 25 in the extending direction and the length of the rib 23 that defines the length of the inner inner duct 26 are defined. The length in the extension direction is different. Therefore, as shown in FIG. 5, the resonance frequency of the sound wave F1 passing through the inner duct 25 and the resonance frequency of the sound wave F2 passing through the inner inner duct 26 can be set to different values. Then, the sound wave F1 having a resonance frequency generated in the outer inner duct 25 and the sound wave F2 having a resonance frequency generated in the inner inner duct 26 are separately separated into sound waves passing through a portion other than the

inner ducts

25 and 26 in the duct 20. Can interfere with. Therefore, among the sound waves of each frequency passing through the duct 20, the sound pressure levels of the sound waves F1 and F2 of the frequencies corresponding to the resonance frequencies can be lowered separately.

According to the duct 20 of the present embodiment, the generation of intake noise can be suppressed in this way.

FIG. 6 shows the flow of intake air in the duct 20 of the present embodiment.

In the duct of the comparative example in which the

ribs

22 and 23 are not provided on the duct main body 21, the distance between the outer portion of the duct main body 21 in the bending direction and the inner portion of the duct main body 21 facing the outer portion in the bending direction (FIG. 6). L3) becomes longer. The outer portion of the duct main body 21 in the bending direction corresponds to a portion where a gas flow that travels straight without bending inside the curved portion 24 of the duct main body 21 abuts. Therefore, in the duct of the comparative example, it is difficult for the gas flow that hits the outer portion of the duct main body 21 in the bending direction and is deflected to reach the inner portion of the duct main body 21 in the bending direction. Therefore, in the duct of the comparative example, the vortex generation region (Sb in FIG. 6) in which the vortex is generated tends to be large inside the duct main body 21 in the bending direction.

In this respect, in the duct 20 of the present embodiment, the inside of the curved portion 24 of the duct main body 21 is divided into three passages P1 to P3 by two

ribs

22 and 23. Therefore, as compared with the above distance (L3) in the duct of the comparative example, the distance between the outer portion in the bending direction and the inner portion in the bending direction where the straight gas flow without bending hits the individual compartment passages P1 to P3 ( L4) in FIG. 6 can be shortened. As a result, the gas flow deflected by hitting the outer portion in the bending direction in the compartment passages P1 to P3 can easily reach the inner portion in the bending direction in the compartment passages P1 to P3. The vortex generation region (S1, S2, S3 in FIG. 6) inside in the bending direction can be reduced. As described above, according to the duct 20 of the present embodiment, the vortex generation region (specifically, the sum of the regions S1 to S3) in which the gas is difficult to flow can be made smaller than that of the duct of the comparative example. The flow path resistance of the above can be reduced.

(3)

Internal ducts

25 and 26 are partitioned in the middle of the extension direction of the duct main body 21 inside the cylindrical duct main body 21. Therefore, the generation of intake noise can be suppressed.

(4) Two

ribs

22 and 23 extending so as to connect the facing portions on the inner surface of the duct main body 21 are provided inside the duct main body 21. Therefore, the

ribs

22 and 23 and the inner surface of the duct main body 21 can form the

internal ducts

25 and 26 inside the duct main body 21.

(5) The

ribs

22 and 23 are arranged inside the curved portion 24 of the duct main body 21 so as to be arranged from the inside to the outside in the bending direction of the curved portion 24. As a result, the vortex generation region inside the duct main body 21 can be reduced, so that the flow path resistance of the duct 20 can be reduced.

(Other embodiments)
Each of the above embodiments can be modified and implemented as follows. Each of the above embodiments and the following modified examples can be implemented in combination with each other within a technically consistent range.

-In the first embodiment, a plurality of cylindrical inner pipe portions 12 may be provided inside the duct main body 11. In the same configuration, by providing a plurality of inner tube portions having different lengths in the extending direction, the resonance frequency of the sound wave passing through each inner tube portion can be set to a different value. As a result, among the sound waves of each frequency passing through the duct 10, the sound pressure level of the sound waves corresponding to the resonance frequencies can be lowered separately.

-In the first embodiment, the shape of the duct main body 11 and the inner pipe portion 12 is not limited to a cylindrical shape, and can be any cylindrical shape such as a polygonal tubular shape or an elliptical tubular shape.

-In the second embodiment, the shape of the duct main body 21 is not limited to a cylindrical shape, and can be any cylindrical shape such as a polygonal cylinder shape or an elliptical cylinder shape. That is, the duct main body 11 and the inner pipe portion 12 of the first embodiment and the duct main body 21 of the second embodiment may have an annular cross-sectional shape. In this case, the term "annular" refers to any structure that forms a loop, i.e. a continuous shape without ends. "Circular" shapes include, but are not limited to, circular, elliptical, and polygons with sharp or rounded corners.

-In the second embodiment, three or more ribs extending so as to connect the facing portions on the inner surface of the duct main body 21 may be provided.

-In the second embodiment, ribs extending so as to connect the opposing portions on the inner surface of the duct main body 21 may be provided on the linearly extending portions of the duct main body 21.

-In the second embodiment, the shape of the plurality of ribs can be arbitrarily changed as long as it can form an internal duct through which gas can pass in the middle of the extension direction of the duct main body 21. can. Further, the plurality of ribs are not limited to the arrangement arranged from the inside to the outside in the bending direction of the curved portion 24, and can be arranged in an arrangement in any direction.

-In the second embodiment, a slight gap may be provided between the

ribs

22 and 23 and the inner surface of the duct body 21. In short, the inside of the duct main body 21 may be partitioned by the

ribs

22 and 23 to the extent that a resonance phenomenon occurs inside the

internal ducts

25 and 26.

-In each embodiment, if the shape is such that the expander is not arranged in the arranged portion of the

internal ducts

14, 25, 26 in the duct

main bodies

11 and 21, the direction orthogonal to the center line of the duct

main bodies

11 and 21 The cross-sectional shape of the duct

main body

11 and 21 may be different in each part in the extending direction. In this case, it is preferable that the inner surfaces of the

duct bodies

11 and 21 are formed of smooth surfaces having no steps.

-In each embodiment, the relationship between the length of the

duct bodies

11 and 21 in the extension direction and the lengths of the

internal ducts

14, 25 and 26 in the extension direction, and the

duct bodies

11 and 21 and the internal duct 14 in the extension direction, The relative positional relationship with 25 and 26 can be arbitrarily changed according to the frequency of the sound wave for which the sound pressure level is desired to be suppressed.

-In the first embodiment, at least one of the duct main body 11 and the inner pipe portion 12 may be formed of a fiber molded body made of a non-woven fabric. In the second embodiment, at least one of the duct body 21 and the

ribs

22 and 23 may be formed of a fiber molded body. That is, a part or all of the

ducts

10 and 20 may be formed by the fiber molded body.

-In addition to integrally molding the

entire ducts

10 and 20 with one mold, the

ducts

10 and 20 can be formed by molding a plurality of divided bodies and joining (adhering, welding) the divided bodies. can.

-The duct according to each of the above embodiments can be applied to a duct other than the intake duct of an internal combustion engine, for example, a duct for an air conditioner, as long as the duct allows gas to pass through the inside.

10, 20 ...

Ducts

11 and 21 ... Duct body 12 ...

Inner pipes

12A, 12B, 12C, 12D ... Walls 14 ...

Internal ducts

22, 23 ... Ribs 24 ... Curved parts 25 ... Outer inner ducts 26 ... Inner inner ducts

Claims

A duct body that has an annular cross-sectional shape and allows gas to pass through,
It has a plurality of partition walls extending in the extending direction of the duct body, and has a plurality of partition walls.
The plurality of partition walls are provided in a non-dispersed portion inside the duct body that does not have an expander in a manner in which the plurality of partition walls are arranged at intervals in a direction intersecting the extending direction. An internal duct through which gas can pass is formed in the middle of the extending direction of the arranged portion.
duct.
The plurality of partition walls include a plurality of wall portions constituting the inner pipe portion, and include the plurality of wall portions.
The duct according to claim 1, wherein the inner pipe portion has an annular cross-sectional shape and extends in the extending direction inside the duct main body.
The duct according to claim 1, wherein the plurality of partition walls include a plurality of ribs extending so as to connect facing portions on the inner surface of the duct body.
The duct body has a curved portion that extends in a curved manner.
The duct according to claim 3, wherein the plurality of ribs are arranged inside the curved portion from the inside to the outside in the bending direction of the curved portion.