JP2021102934A - Sound absorber and sound absorption sheet of internal combustion engine - Google Patents

Abstract

To stably obtain superior sound absorption performance for a long period by making it hard for inorganic fibers in a sound absorber to deviate, and to prevent a welding defect by eliminating protrusion of the inorganic fiber to a weld zone.SOLUTION: A sound absorption sheet 1 includes a weft 2 made of bulky inorganic fiber roving extending along a sheet width, and a warp 3 extending along a sheet length. The inorganic fiber roving has 1.5 mass% or less of a stuck bundling agent, and contains no other organic material. Both sheet width-directional ends of the weft 2 are woven with the warp 3 to form end woven fabric parts 4, and a part of the sheet width-directional middle of the weft 2 is woven with the warp 3 to form an intermediate woven fabric part 5. A sheet width-directional part of the weft 2 is partially a nonwoven fabric part 6 which is not woven with the warp 3. Both sheet width-directional ends of the weft 2 are continuous folded-back ends 7 which are not cut.SELECTED DRAWING: Figure 1

Description

The present invention relates to a silencer of an internal combustion engine and a sound absorbing sheet arranged therein.

A sound absorbing material made of inorganic fibers is arranged between the inner pipe and the outer pipe of the silencer of the internal combustion engine. As the conventional sound absorbing material made of inorganic fibers, various materials such as those formed by winding a glass wool mat, those formed by molding glass wool into a cylinder, and those packed with long glass fibers in a bag (Patent Document 1) are available. There is also disclosed that glass fiber roving is used (Patent Documents 2 and 3).

JP-A-2007-170315 JP-A-2007-182878 Japanese Patent Application Laid-Open No. 2013-519037

However, the conventional sound absorbing material made of inorganic fibers has the following problems.
-The exhaust gas pressure sometimes caused a bias in the inorganic fibers in the silencer. When bias occurs, the sound absorption performance tends to deteriorate, and the quality fluctuation over a long period of time becomes large.
-In the work of integrating the inner pipe and the outer pipe by welding, if the inorganic fiber of the sound absorbing material protrudes into the welded part, it causes poor welding. In addition, it may lead to a failure of the welding equipment.
-Inorganic fibers may be mixed with organic matter, but if a large amount of organic matter is contained, the organic matter vaporizes in the usage environment, causing smoke and offensive odors. It is also not preferable because of the adhesion of hydrocarbons.

Therefore, an object of the present invention is to make it difficult for the inorganic fibers to be biased in the silencer, to stably obtain excellent sound absorption performance for a long period of time, and to prevent the inorganic fibers from protruding into the welded portion to prevent welding defects. There is. More preferably, it is to reduce the vaporization of organic matter and prevent smoke generation and offensive odor.

The present inventors have considered the use of inorganic fiber roving and found that bulky inorganic fiber roving is promising, but only bulky inorganic fiber roving is likely to cause fibers to protrude into the welded portion. , It was found that manual repair is required and continuous production is likely to be hindered. We also considered weaving bulky inorganic fiber rovings into woven fabrics, but found that the sound absorption performance was likely to deteriorate due to the constraints between the fibers. Further studies have been made based on these, and the present invention has been reached.

[1] Sound absorbing sheet A sound absorbing sheet provided in a silencer of an internal combustion engine.
Includes wefts made of bulky inorganic fiber rovings extending in the sheet width direction and warp threads extending in the sheet length direction.
At least both ends of the weft in the sheet width direction are woven with the warp to form an end woven fabric portion, and the width of each end woven fabric portion is 1/4 or less of the sheet width.
A sound absorbing sheet characterized in that a part of the weft in the sheet width direction is a non-woven part that is not woven with the warp.

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(A) Since both ends of the bulky inorganic fiber roving are restrained by the warp threads of the end woven fabric part of the sound absorbing sheet, this can be wound and arranged on the muffler with less bias, and exhaust gas resistance. It has excellent pressure resistance and can prevent bias of inorganic fibers even when used for a long time. Further, the bulky inorganic fiber roving has high sound absorption because it exists in a bulky state without being restrained especially in the non-woven part. As a result, excellent sound absorption performance can be stably obtained for a long period of time.
(B) In addition, since both ends of the inorganic fiber roving are restrained by the warp threads of the end woven fabric part, when the sound absorbing sheet is arranged in the silencer, the inorganic fiber does not protrude into the welded part and welding failure occurs. Can be prevented.
(C) The edge woven fabric portion is not extensible in the sheet length direction, but the non-woven portion is extensible in the sheet length direction. Therefore, even if there are undulations (diameter difference or curvature) on the outer peripheral surface of the inner pipe, the non-woven color portion extends accordingly, so that the sound absorbing sheet can be easily wound around the inner pipe.

Here, both ends of the weft in the sheet width direction are preferably continuous folded ends that have not been cut. This is because the fluff of the inorganic fiber is eliminated and welding defects can be prevented more reliably.
Such a sound absorbing sheet in which both ends of the weft are folded ends can be obtained by using a loom such as a shuttle loom that skips the weft by the reciprocating motion of the shuttle or a narrow needle loom that does not use a shuttle. It can be manufactured by adjusting the mounting position.
In the case of a narrow needle loom, binder threads can be entwined at both ends in the sheet width direction. Both ends of the sound absorbing sheet can be fixed by heat welding the entwined binder threads. When a binder yarn is used, a yarn made of a polyolefin-based thermoplastic resin such as polyester, polyethylene, or polypropylene is desirable because it has less harmful gas during heating. By entwining a metal thread instead of the binder thread, the strength of the end portion can be reinforced. In that case, the metal thread is preferably a thread made of a heat-resistant alloy such as stainless steel or an iron / chromium alloy.

The following aspects (a), (b) and (c) are included in the middle of the weft in the sheet width direction.
(A) A portion of the weft in the sheet width direction is woven with the warp to form an intermediate woven fabric portion, and the width of the intermediate woven fabric portion is 1/3 or less of the sheet width.
It is possible to more reliably prevent the bias of the inorganic fiber when it is arranged in the silencer and when it is used.
The intermediate woven fabric portion is preferably located at the center of the weft in the sheet width direction. This is because it is easy to fold the sound absorbing sheet at the intermediate woven fabric part.
The intermediate woven fabric portion does not have extensibility in the sheet length direction, which reduces the extensibility of the non-woven portion. However, if the outer peripheral surface of the inner pipe has no undulations or is small, it can be applied without any problem.

(B) An embodiment in which an intermediate sewn portion sewn in the sheet length direction by the sewing thread is formed in a part of the middle of the weft in the sheet width direction.
When the sewing thread melts, it can be more reliably prevented from being biased in the silencer, and when the sewing thread does not melt, it can be placed in the silencer and when it is used.
The intermediate sewn portion is preferably located in the center of the weft in the sheet width direction. This is because it is easy to fold the sound absorbing sheet at the intermediate sewing part and fold it.
The intermediate sewn portion may not be stretchable in the sheet length direction, or may be stretchable in the sheet length direction due to the stretchable sewing thread and / or the stretchable seam as described later. is there.

(C) A mode in which the middle of the weft in the sheet width direction is a non-woven portion. That is, neither the intermediate woven fabric portion nor the intermediate woven fabric portion is formed in the middle.
Also in this embodiment, the bias of the inorganic fibers can be prevented to a certain extent or more when the inorganic fibers are arranged in the silencer and when used.
It can also be applied when there are large undulations on the outer peripheral surface of the inner pipe.

In the inorganic fiber roving, it is preferable that the adhered converging agent is 1.5% by mass or less and does not contain any other organic content. This is because the amount of exhaust gas is extremely small during heating.

[2] Silent device for internal combustion engine The sound absorbing sheet according to any one of claims 1 to 8, which is arranged in a wound shape between the inner pipe, the outer pipe, and the inner pipe and the outer pipe. A silencer for an internal combustion engine, including, in which both ends of the outer pipe are welded to the inner pipe.

The sound absorbing sheet may be arranged in a wound shape after being folded to increase its thickness.

Another functional member may be interposed between the sound absorbing sheet and the inner pipe.

According to the present invention, the inorganic fibers are less likely to be biased in the silencer, excellent sound absorption performance can be stably obtained for a long period of time, and the inorganic fibers can be prevented from protruding into the welded portion to prevent welding defects. it can.

FIG. 1 is a front view of the sound absorbing sheet of the first embodiment. FIG. 2A is a schematic view when the sound absorbing sheet is folded in the sheet length direction, and FIG. 2B is a schematic view when the sound absorbing sheet is folded in the sheet width direction. FIG. 3A is a partially broken front view of the silencer on which the sound absorbing sheet is arranged, and FIG. 3B is a partially broken front view of the sound silencer on which the sound absorbing sheet and the metal fiber are arranged. FIG. 4 is a front view of the sound absorbing sheet of the second embodiment. FIG. 5 is a schematic view showing another example of the seam of the intermediate sewn portion of the sound absorbing sheet. FIG. 6 is a front view of the sound absorbing sheet of the third embodiment.

[1] Weft (inorganic fiber roving)
The inorganic fiber is not particularly limited, but glass fiber, basalt fiber, silica fiber, rock wool, alumina fiber, ceramic fiber and the like can be exemplified, and inexpensive and versatile glass fiber is preferable.
The roving count is not particularly limited, but is preferably 200 to 9600 TEX, more preferably 1200 to 7000 TEX.
The fiber diameter of the roving is not particularly limited, but is preferably 9 to 30 μm, more preferably 12 to 24 μm.
Bulky inorganic fiber roving can be obtained by opening the fibers with an air blow or the like. Bulky is preferably bulky with a shrinkage ratio of 1 to 10% in the length direction, and particularly preferably bulky with a shrinkage ratio of 3 to 7% from the viewpoint of sound absorption performance and prevention of fiber scattering. The reduction ratio can be adjusted by air pressure.

[2] Warp The warp is not particularly limited, but roving made of fiber filaments, spun yarn, twisted yarn and the like can be exemplified, and roving is preferable, and inorganic fiber roving is more preferable.
In the case of roving, the count is not particularly limited, but 200 to 9600 TEX is preferable, and 1200 to 7000 TEX is more preferable.
The fiber diameter in the case of roving is not particularly limited, but is preferably 9 to 30 μm, more preferably 12 to 24 μm.
The warp fiber is not particularly limited, but inorganic fiber, metal fiber, organic fiber and the like can be exemplified, and inorganic fiber is preferable.
The inorganic fiber is not particularly limited, and examples thereof include glass fiber, basalt fiber, silica fiber, rock wool, alumina fiber, and ceramic fiber, and inexpensive and versatile glass fiber is preferable.
The organic fiber is not particularly limited, and examples thereof include fibers made of natural materials such as polyester, polypropylene, polyethylene, nylon, aramid, and cotton, synthetic rubber, and carbon.

[3] End woven fabric portion The weaving method of the end woven fabric portion is not particularly limited, but plain weave is preferable in terms of workability.
The width of each end woven fabric portion can be determined by the thickness, number of warp threads, and pitch of the warp threads.
The width of each end woven fabric portion is preferably 1/100 to 1/4, more preferably 1/6 or less, and most preferably 1/8 or less of the sheet width. If the width of each end woven fabric portion is too small, the binding property at both ends of the weft is reduced, and if the width of each end woven fabric portion is too large, the width of the non-woven portion is reduced and the sound absorption property is reduced.
The width of each end woven fabric portion is preferably 2 to 50 mm, particularly preferably 10 to 30 mm in terms of numerical values.
The density of the yarn is not particularly limited, but is preferably 1 to 24 yarns per 25 mm, more preferably 2 to 14 yarns, regardless of the warp yarn and the weft yarn.
Mass of each end cloth portion is not particularly limited, but is preferably ^{300~4000g / m 2, 600~2400g / m} 2 is more preferable.
When there is no central woven fabric portion, the distance between the centers of the end woven fabric portions at both ends is not particularly limited, but is preferably 25 to 250 mm, more preferably 50 to 150 mm.

[4] Intermediate woven fabric portion As described above, the intermediate woven fabric portion is preferably located at the center of the weft in the sheet width direction, but may be located at a location other than the center, and the number may be one or more. ..
The weaving method of the intermediate woven fabric portion is not particularly limited, but plain weave is preferable in terms of workability.
The width of the intermediate woven fabric portion can be determined by the thickness, number of warp threads, and pitch of the warp threads.
The width of the intermediate woven fabric portion is preferably 1/50 to 1/3, more preferably 1/4 or less, and most preferably 1/5 or less of the sheet width.
The width of the intermediate woven fabric portion is preferably 2 to 100 mm, particularly preferably 10 to 40 mm in terms of numerical values.
The density of the yarn is not particularly limited, but is preferably 1 to 24 yarns per 25 mm, more preferably 2 to 14 yarns, regardless of the warp yarn and the weft yarn.
Mass of the middle end cloth portion is not particularly limited, but is preferably ^{300~4000g / m 2, 600~2400g / m} 2 is more preferable.
The distance between the centers of the central woven fabric portion and each end woven fabric portion and the distance between the centers of the central woven fabric portions are not particularly limited, but are preferably 25 to 250 mm, more preferably 50 to 150 mm.

[5] Sewing thread The sewing thread is not particularly limited, and examples thereof include spun yarn and twisted yarn.
The fibers of the spun yarn are not particularly limited, and examples thereof include inorganic fibers, metal fibers, and organic fibers. Inorganic fibers are particularly preferable.
The inorganic fiber thread is not stretchable, but is suitable when stretchability is not required or when a highly stretchable seam is formed, as will be described later.
As sewing threads with high extensibility, the product name Ace Crown manufactured by Ace Crown, the product name Hyper, the product name Eiffel sewing thread (# 30, # 50) manufactured by Kanagawa, the product name Leona (# 50), and Fujix Co., Ltd. Examples of organic fiber yarns such as Woolly yarn manufactured by Woolly, Resilon (245dTEX # 50), and Unilon (# 50) manufactured by Asahi Kasei Leona Co., Ltd. can be exemplified.

[6] Intermediate sewn part If the outer peripheral surface of the inner pipe has no undulations or is small, the intermediate sewn part does not need to be elastic, so the intermediate sewn part may be sewn in a straight line with a general sewing thread. ..
However, if there are large undulations on the outer peripheral surface of the inner pipe, the intermediate sewn portion also needs to be elastic in order to improve obedience. Therefore, the intermediate sewn portion uses a highly extensible sewing thread or a highly extensible seam. It is preferable to set it to.
Sewing threads with high extensibility have been illustrated above.
Examples of highly extensible seams include (a) stretch stitches, (b) zigzag stitches, (c) half reverse stitches, and (d) dotted zigzag stitches shown in FIG.

[7] Silencer The sound absorbing sheet may be wound once, or may be wound multiple times to increase the thickness. Further, it may be folded in the sheet length direction as shown in FIG. 2 (a) or folded in the sheet width direction as shown in FIG. 2 (b) to increase the thickness and then wound. .. When folding in the sheet width direction, it is preferable to weave in the intermediate woven fabric portion.
As shown by the arrows in FIGS. 1 and 2, the sound absorbing sheet is basically wound so as to be circumferential in the sheet width direction (direction in which the weft extends). However, it can also be wound so as to be circumferential in the sheet length direction (the direction in which the warp threads extend).

As another functional member interposed between the sound absorbing sheet and the inner pipe, a sleeve-shaped material such as metal wool such as stainless wool, metal foil, metal mesh, or a knit made of glass fiber can be exemplified.

Next, examples of the present invention will be described with reference to the drawings. The structure, shape, dimensions, materials, numerical values, etc. described in the examples are examples, and can be appropriately changed as long as they do not deviate from the gist of the invention.

[Example 1]

FIG. 1 shows the sound absorbing sheet 1 of Example 1, FIG. 2 shows an example of folding the sound absorbing sheet 1, and FIG. 3 shows a silencer 10 in which the sound absorbing sheet 1 is arranged.

The sound absorbing sheet 1 includes a weft thread 2 made of bulky inorganic fiber roving extending in the sheet width direction and a warp thread 3 made of inorganic fiber roving extending in the sheet length direction. In each of the inorganic fiber rovings, the adhered converging agent is 1.5% by mass or less, and other than that, no organic content is contained.

Both ends of the weft 2 in the sheet width direction are woven with the warp 3 to form an end woven fabric portion 4, and the width w1 of each end woven fabric portion 4 is, for example, 1/50 to 1/50 of the sheet width W. It is 10.
A part of the weft 2 in the sheet width direction (the central portion in this example) is woven with the warp 3 to form the intermediate woven fabric portion 5, and the width w2 of the intermediate woven fabric portion 5 is, for example, the sheet width. It is 1/20 to 1/5 of W.
A part of the weft 2 in the sheet width direction (in this example, a portion between each end woven fabric portion 4 and the intermediate woven fabric portion 5) is a warp yarn 3 and an unwoven non-woven portion 6.
Both ends of the weft 2 in the sheet width direction are continuous folded ends 7 that have not been cut.

The silencer 10 shown in FIG. 3A includes an inner pipe 11, an outer pipe 12, and a sound absorbing sheet 1 arranged in a wound shape between the inner pipe 11 and the outer pipe 12. It is a thing.
The silencer 10 shown in FIG. 3B is a metal fiber 14 such as stainless steel wool and sound absorbing material arranged in a wound shape between the inner pipe 11, the outer pipe 12, and the inner pipe 11 and the outer pipe 12. It is configured to include the sheet 1.

A plurality of through holes are formed in the inner pipe 11. The inner pipe 11 of this example has no undulations on the outer peripheral surface, and the sound absorbing sheet does not need to be elastic.
The sound absorbing sheet 1 is folded in the sheet width direction to increase the thickness, and then wound so as to be circumferential in the sheet width direction (direction in which the weft extends).
Both ends of the outer pipe 12 are joined to the inner pipe 11 by a welded portion 13.

[Example 2]
The sound absorbing sheet 1 of the second embodiment shown in FIG. 4 is sewn in the middle part (central part in this example) of the weft thread 2 in the sheet width direction with the sewing thread 15 in the sheet length direction instead of the intermediate woven fabric part. It differs from the first embodiment in that the broken intermediate sewn portion 16 is formed, and is the same as the first embodiment in other respects.
The intermediate sewing portion 16 is linearly sewn with a general sewing thread 15 having low extensibility, but a sewing thread having high extensibility may be used or a seam having high extensibility (FIG. 5) may be used. You can also do it.
The sound absorbing sheet 1 of the second embodiment can also be arranged in the silencer 10 in the same manner as in the first embodiment.

[Example 3]
The sound absorbing sheet 1 of the third embodiment shown in FIG. 6 is different from the first embodiment in that the middle of the weft thread 2 in the sheet width direction is the non-woven portion 6, and the other parts are the same as those of the first embodiment.
The sound absorbing sheet 1 of the third embodiment can also be arranged in the silencer 10 in the same manner as in the first embodiment.

According to Examples 1, 2 and 3, the bias of the inorganic fiber in the silencer 10 is unlikely to occur, excellent sound absorption performance can be stably obtained for a long period of time, and the inorganic fiber protrudes into the welded portion 13. Welding defects can be prevented without it.

The present invention is not limited to the above-described embodiment, and can be appropriately modified and embodied without departing from the spirit of the invention.

1 Sound absorbing sheet 2 Weft 3 Warp 4 End woven fabric 5 Intermediate woven fabric 6 Non-woven fabric 7 Folded end 10 Silent device 11 Inner pipe 12 Outer pipe 13 Welded part 14 Metallic fiber 15 Sewing thread 16 Intermediate sewn part

Claims (12)

A sound absorbing sheet (1) arranged in a silencer (10) of an internal combustion engine.
A weft (2) made of bulky inorganic fiber roving extending in the sheet width direction and a warp (3) extending in the sheet length direction are included.
At least both ends of the weft (2) in the sheet width direction are woven with the warp (3) to form an end woven fabric portion (4), and the width (w1) of each end woven fabric portion (4) is the sheet. It is 1/4 or less of the width (W),
A sound absorbing sheet characterized in that a part of the weft (2) in the sheet width direction is a warp (3) and an unwoven non-woven portion (6). The sound absorbing sheet according to claim 1, wherein both ends of the weft (2) in the sheet width direction are continuous folded ends (7) that are not cut. A part of the weft (2) in the middle in the sheet width direction is woven with the warp (3) to form an intermediate woven fabric portion (5), and the width of the intermediate woven fabric portion (5) is 1 of the sheet width. The sound absorbing sheet according to claim 1 or 2, which is 3/4 or less. The sound absorbing sheet according to claim 3, wherein the intermediate woven fabric portion (5) is located at the center of the weft thread (2) in the sheet width direction. The sound absorbing sheet according to claim 1 or 2, wherein an intermediate sewn portion (15) sewn in the vertical direction with the sewing thread is formed in a part of the middle of the weft thread (2) in the sheet width direction. The sound absorbing sheet according to claim 5, wherein the intermediate sewing portion (15) is located at the center of the weft thread (2) in the sheet width direction. The sound absorbing sheet according to claim 5 or 6, wherein the intermediate sewing portion (15) is sewn with an extensible sewing thread. The sound absorbing sheet according to claim 5, 6 or 7, wherein the intermediate sewing portion (15) is sewn into an stretchable seam. The sound absorbing sheet according to claim 1 or 2, wherein the middle of the weft (2) in the sheet width direction is a non-woven portion (6). The sound absorbing sheet according to any one of claims 1 to 9, wherein the inorganic fiber roving contains 1.5% by mass or less of the adhering converging agent and does not contain any other organic matter. The invention according to any one of claims 1 to 10, wherein the inner pipe (11), the outer pipe (12), and the inner pipe (11) and the outer pipe (12) are arranged in a wound shape. A silencer for an internal combustion engine, including a sound absorbing sheet (1), wherein both ends of an outer pipe (12) are welded to an inner pipe (11). The silencer for an internal combustion engine according to claim 11, wherein the sound absorbing sheet (1) is arranged in a wound shape after being folded to increase its thickness.

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