JP2003214134A - Sound absorbing body and muffler for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound deadner which is prevented from generation of off-flavor when the sound deadner is used in a muffler for an internal combustion engine. <P>SOLUTION: The sound deadner 1 consists of a bag body 11 and a sound deadning material 12. The bag body 11 is formed of non-woven cloth formed of resin fiber of polypropylene and the like. A long fiber sound deadning material is used as the sound deadning material 12. The bag body 11 is filled with the sound deadning material 12 through its opening part. Thereafter, the opening part of the bag body 11 is closed by a bag body 11 through thermofusion. This method constitutes the sound deadner 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorber and a silencer for an internal combustion engine using the sound absorber.

[0002]

2. Description of the Related Art Generally, in a silencer for an internal combustion engine,
The casing is filled with a sound absorbing material made of short fibers such as glass wool and a sound absorbing material made of long fibers, so that exhaust noise is reduced.

By the way, the casing of a silencer is usually
It has a pair of halves, and one of the halves is filled with a predetermined amount of sound absorbing material, and then the other half is abutted against and fixed to the one half to form a silencer. Therefore, if the sound absorbing material made of fibers is packed into one half without any treatment, a part of the sound absorbing material will stick out from the one half, and this will cause the other half to become one half. There is a problem that they are sandwiched between the two halves when they are fixed by abutting.

Therefore, in the conventional silencer, the sound absorbing material is previously contained in a polypropylene bag body, and an appropriate number of the sound absorbing material is filled into one half body, and then the pair of half bodies is fixed. . This prevents a part of the fibers constituting the sound absorbing material from being sandwiched between the pair of halves.

[0005]

When the sound absorbing material is packed in the bag, the sound deadening effect of the sound absorbing material is deteriorated. Therefore, a small hole is formed in each part of the bag body, and exhaust sound is introduced into the bag body through the small hole. However, even if a small hole is formed in the bag, there is a problem that it is difficult to sufficiently prevent the deterioration of the sound deadening effect. Also, when packing the sound absorbing material into the bag, it is necessary to open the opening, but the inner surfaces of one side and the other side of the bag are often stuck to each other due to static electricity. . In such a case, there is a problem that it takes a lot of time to open the opening of the bag. In order to solve such a problem, an antistatic agent is applied to the inner surface of the bag body in advance. However, when a bag body coated with an antistatic agent is used, and when a sound absorbing material is used in a place where the bag body burns, the antistatic agent burns at the same time as the bag body burns and produces an offensive odor. There is a problem of doing.

[0006]

The present invention has been made to solve the above problems, and the first invention is
A sound absorbing body in which a long-fiber sound absorbing material is housed inside a bag body, wherein the bag body is formed of a non-woven fabric. According to a second aspect of the present invention, a ring-shaped bundle of long-fiber sound-absorbing materials is arranged in a radial direction so that one side and the other side of the bundle of long-fiber sound-absorbing materials wound in a ring contact each other. Crushed,
In that state, a bundle of long-fiber sound absorbing materials is bound by a binding member. A third invention is a silencer for an internal combustion engine in which a casing is filled with a sound absorbing body, wherein the sound absorbing body according to claim 1 or 2 is used as the sound absorbing body. In the third invention,
It is desirable that the casing has a pair of halves fixed to each other.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows a sound absorbing body 1 according to the present invention. The sound absorbing body 1 is a bag body 1.
1 and a sound absorbing material 12 housed inside.

The bag 11 is made of non-woven fabric. As is well known, the non-woven fabric can be formed by mechanically entangling resin fibers such as polypropylene and polyethylene or by heat fusion. As shown in FIG. 2, the bag body 11 is formed in a rectangular shape as a whole.
Three of the sides are closed, and the opening 11a is provided on the remaining one side.
Are formed. The shape of the bag body 11 is not limited to the rectangular shape, and may be appropriately changed depending on the shape of the silencer for an internal combustion engine in which the sound absorbing body 1 is used. The bag 11 is
Probably because the static electricity is discharged from the tip of each fiber constituting the non-woven fabric, it is hardly charged. Therefore, although the antistatic agent is not applied to the inner surface of the bag body 11, the opening 11a of the bag body 11 can be easily opened.

The sound absorbing material 12 is made of short fibers such as glass wool or long fibers such as glass fibers, and is packed in the bag body 11 through its opening 11a as shown in FIG. As described above, since the bag body 11 is hardly charged, the sound absorbing material 12 can be easily packed in the bag body 11. After the sound absorbing material 12 is packed in the bag body 11, by heat-sealing the portions (hatched portions in FIG. 2) in the vicinity of the openings 11a between the one side portion and the other side portion of the bag body 11, The opening 11a of the bag 11 is closed. With this, the sound absorber 1 is configured.

In the sound absorbing body 1 thus constructed, since the bag body 11 is made of the non-woven fabric, exhaust sound can sufficiently enter into the bag body 11. Moreover, the bag body 11 itself made of non-woven fabric also absorbs the exhaust sound. Therefore, the exhaust noise can be sufficiently suppressed. Further, since the bag body 11 made of a non-woven fabric is hardly charged, the opening 11a of the bag body 11 can be easily opened, and the sound absorbing material 12 is introduced into the bag body 11 through the opening 11a.
Can be packed easily. Further, even if the bag body 11 burns due to heat of exhaust gas or the like, the bag body 11
Since the antistatic agent is not applied to, no offensive odor is generated.

FIG. 3 shows a sound absorbing body 2 according to the second invention. The sound absorber 2 includes a long fiber sound absorbing material 21 and a binding tape (binding member) 22 that binds the long fiber sound absorbing material 21. The long-fiber sound-absorbing material 21 is made of long fibers such as glass fiber like the long-fiber sound-absorbing material 12, and as shown in FIG. 4, by being wound with the longitudinal direction facing the circumferential direction. , Are bundled in a ring shape as a whole. The long fiber sound absorbing material 21 can be bundled in a ring shape by being wound around the outer circumference of a rod or a cylinder having a circular cross section.

The binding tape 22 is bundled in a crushed state such that one side portion and the other side portion of the bundle of the ring-shaped long-fiber sound-absorbing material 21 come into contact with each other, so that the long-fiber sound-absorbing material 21 is separated. It is intended to prevent spillage, and is made of a resin tape such as polypropylene that is burned by the heat of exhaust gas and does not generate an offensive odor at that time. The long-fiber sound absorbing material 2 with the binding tape 22
When binding the bundle of No. 1, as shown in FIG. 5, first, the bundle of the long-fiber sound-absorbing material 21 in a ring shape is crushed in the radial direction, and the inner surface of one side portion and the inner surface of the other side portion are separated. Contact each other. Then, the long fiber sound absorbing material 21 is bound in a crushed state by winding the binding tape 22 around one end and the other end of the bundle of the crushed long fiber sound absorbing material 21. Thereby, the sound absorber 2 is configured. The bundle of the crushed long-fiber sound-absorbing materials 21 may be bound at only one location in the center with the binding tape 22, or at three or more locations.

In the sound absorbing body 2 thus constructed, since the bag body is not used, the sound absorbing material 21 can sufficiently exhibit the sound deadening effect. Further, it is unnecessary to open the opening of the bag body. Therefore, the sound absorbing body 2 can be easily manufactured. Further, since the binding tape 22 is made of a resin tape that does not generate an offensive odor even if it burns, the binding tape 22 does not generate an offensive odor.

6 and 7 show a silencer 3 for an internal combustion engine according to the third invention. The silencer 3 has a casing 31. The casing 31 is composed of a pair of halves 32 and 33, and the halves 32 and 33 are fixed by welding in a state of abutting each other. A tubular body 34 is disposed so as to penetrate through one side portion inside the casing 31. The one end portion and the other end portion of the tubular body 34 are formed by the respective half bodies 3.
It is sandwiched between the butting surfaces of the two and 33 and is fixed to the respective half bodies 32 and 33 by welding or the like. The tube 34
Exhaust pipes (not shown) are connected to both ends of each.

A sound absorbing body 1A is wound around the outer peripheral surface of the tubular body 34. The sound absorber 1A has the same structure as the sound absorber 1 except that the sound absorber 1A has a substantially constant thickness. That is, it is configured by packing the long-fiber sound absorbing material 12 in the bag body 11. Tubular body 34 around which the sound absorbing body 1A is wound
A large number of small holes 34a penetrating the peripheral wall portion are formed in the peripheral wall portion. The sound absorber 1B is packed in the other side portion inside the casing 31. The sound absorber 1B has the same shape as a space defined by the inner surface of the other side portion of the casing 31 and the outer surface of the sound absorber 1A facing the other side portion of the casing 31. The sound absorbing body 1B is composed of a bag body 11 and a long fiber sound absorbing material 12 like the sound absorbing body 1 except that the sound absorbing body 1B has such a shape.

When manufacturing the silencer 3 having the above structure,
Both ends of the tube 34 are temporarily fixed to the one half 32 (33). At this time, the sound absorber 1A may be wound around the tube body 34 in advance, or the sound absorber 1A may be temporarily fixed after the tube body 34 is fixed.
May be wound. Next, the sound absorber 1B is packed in the other side portion of the half body 32 (33). Then, the other half 33 (32)
Are abutted against one half 32 (33), the abutting surfaces are welded to each other, and the half 33, 32 and both ends of the tube 34 are welded and fixed. As a result, the silencer 3
Can be manufactured.

In the muffler 3 having the above structure, the sound absorbing material 1
2 is packed in the bag 11, so that a pair of halves 3
When 2 and 33 are butted against each other, part of the sound absorbing material 12 does not protrude from the half body 32 (33). Therefore, it is possible to reliably prevent a part of the sound absorbing material 12 from being sandwiched between the pair of half bodies 32 and 33.

When exhaust gas from an internal combustion engine (not shown) flows into the silencer 3, the heat of the exhaust gas burns and burns the bag 11. At this time, since the bag 11 is not coated with the antistatic agent, no offensive odor is generated. Bag 1
When 1 burns down, the long-fiber sound-absorbing material 12 packed in the bag body 11 swells entirely and fills the entire inside of the casing 31.

In the muffler 3 having the above structure, the sound absorber 1
Instead of A and 1B, it is also possible to use the sound absorber 2 shown in FIG. In that case, the pipe body 34 is replaced with the one half body 32.
After being temporarily fixed to (33), an appropriate number of sound absorbers 2 are arranged around the tube body 34, and an appropriate number of sound absorbers 2 are provided on the other side of the casing 31 in which the bag body 1B is packed. Stuff. The size of each sound absorber 2 is set to an appropriate size according to the size of the space in which it is arranged. Next, the other half 33 (32) is replaced with the other half 32 (33).
To match. At this time, since the long fiber sound absorbing material 21 is bound by the binding tape 22, the long fiber sound absorbing material 2
A part of 1 is not sandwiched between the halves 32 and 33. Then, the half bodies 32 and 33 are welded and fixed to each other, and both ends of the pipe body 34 are welded and fixed to the other half body 33 (32).

When the exhaust gas flows into the muffler 3 having the above-mentioned structure, the binding tape 22 is burned by the heat of the exhaust gas. At this time, the binding tape 22 is not coated with the antistatic agent, so that no strange odor is generated. When the binding tape 22 burns down, the bundle of long-fiber sound absorbing materials 21 forming each sound absorbing body 2 expands and fills the casing 31.

The present invention is not limited to the above embodiment, but can be modified as appropriate. For example, in the above embodiment, the sound absorber 1 according to the present invention
Although (1A, 1B) and 2 are used for the silencer 3, the sound absorber according to the present invention can be used for an insulator or the like in each cover for preventing radiation noise or for preventing heat insulation.

[0022]

As described above, according to the present invention, the sound deadening effect of the sound absorbing material can be sufficiently exerted, the sound absorbing body using the sound absorbing material can be easily manufactured, and the sound deadening device or the like can be manufactured. When used in a muffler, etc. that consists of two halves, a part of the sound absorbing material is sandwiched between the two halves. It is possible to obtain the effect that the above can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a silencer according to the first invention.

FIG. 2 is a perspective view showing a state before the long-fiber sound absorbing material is packed in the bag body according to the same embodiment.

FIG. 3 is a perspective view showing an embodiment of a silencer according to the second invention.

FIG. 4 is a plan view showing the long-fiber sound absorbing material of the same embodiment wound in a circular ring shape.

FIG. 5 is a perspective view showing a state in which a bundle of long-fiber sound absorbing materials having a ring shape of the same embodiment is crushed and bound with a binding tape.

FIG. 6 is a sectional view taken along line YY of FIG. 7, showing an embodiment of a silencer according to the third invention.

7 is a cross-sectional view taken along the line XX of FIG.

[Explanation of symbols]

1 sound absorber 1A sound absorber 1B sound absorber 2 sound absorber 3 Muffler for internal combustion engine 11 bags 12 Sound absorbing material 21 Long fiber sound absorbing material 22 Bundling tape (bundling member) 31 casing 32 half 33 half body

Claims (4)

[Claims] 1. A sound absorbing body in which a fibrous sound absorbing material is housed inside a bag body, wherein the bag body is formed of a non-woven fabric. 2. A ring-shaped bundle of long-fiber sound-absorbing materials is pressed in the radial direction so that one side and the other side of the bundle of long-fiber sound-absorbing materials wound in a ring contact each other. A sound absorbing body, characterized in that it is crushed and a bundle of long-fiber sound absorbing material is bound in that state by a binding member. 3. A silencer for an internal combustion engine, which comprises a casing filled with a sound absorber, wherein the sound absorber according to claim 1 or 2 is used as the sound absorber. . 4. The silencer for an internal combustion engine according to claim 3, wherein the casing has a pair of halves fixed to each other.