JPH0144729Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an automobile muffler. Conventionally, a muffler for an automobile includes an exhaust pipe 2' having a plurality of holes 1' formed on its circumferential surface, as shown in FIG. 5, and an outer pipe 3' disposed around the exhaust pipe 2'. Also, a sound absorbing material 4' housed between the exhaust pipe 2' and the outer pipe 3' is often used. The sound deadening material 4' is mostly filled with short glass fibers. In the case of short glass fibers, if moisture in the exhaust gas or moisture from cleaning that entered from the muffler outlet side enters the short glass fibers, it will not be easily discharged to the outside by steam etc. It repeatedly evaporates and condenses in the layer and accumulates inside. Therefore, the silencing effect may be reduced. In addition, due to the high heat of the exhaust gas, it may sometimes burn and harden into small glass beads, which creates back pressure on the exhaust gas and not only reduces the silencing effect, but also generates vibration noise, etc. There is a risk. Therefore, sound deadening materials are used that are densely filled with short stainless steel wires, but unlike short glass fibers, the short wires are absorbed by the flow of exhaust gas as they are used, and the short wires leak out to the outside. It may be damaged and the durability may be insufficient.

The present invention has been developed in view of these points, and its gist is an exhaust pipe with a large number of holes formed on its circumferential surface, an outer pipe arranged around the exhaust pipe, and an outer pipe arranged around the exhaust pipe. In an automobile muffler made of a sound-deadening material housed between pipes, the hole formed in the exhaust pipe is the hole formed in the exhaust pipe when a cut is made from the outside of the exhaust pipe in the upstream portion located on the engine side. , a cut-shaped hole is formed with an exhaust gas receiving piece whose cut end protrudes toward the inside of the pipe and faces the flow of exhaust gas, and in the downstream part, when the cut is made from the outside of the exhaust pipe, the cut end protrudes from the inside of the pipe. The cut end protruding from the top is formed into a cut-shaped hole having an exhaust gas outflow piece facing downstream in the flow direction of exhaust gas, and the sound deadening material is made of a stainless steel mesh made of thin stainless steel wires woven into a mesh. The muffler for automobiles is characterized by being filled with silica, and its purpose is to reduce the silencing effect resulting from the accumulation of water in the silencing material layer, and to reduce the amount of clumps of the silencing material. The purpose of the present invention is to provide a muffler for an automobile that does not cause any abnormal noise as a result, does not cause outflow of the sound deadening material, and is excellent in durability.Furthermore, the exhaust gas flows into and out of the sound deadening material well, and the sound is better damped. The purpose of the present invention is to provide an automobile muffler that is effective.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings, FIGS. 1 to 4.

1 is an exhaust pipe with many holes formed on the circumference,
Reference numeral 2 indicates an outer pipe disposed around the exhaust pipe 1, and a sound deadening material 3 is housed between these pipes 1 and 2.

In the case of the present invention, the above-mentioned hole is formed as follows. That is, the hole on the upstream side located on the engine side is formed by making a cut from the outside of the exhaust pipe 1 to form a cut hole 4. An exhaust gas receiving piece 5 is formed in a protruding manner, and a cut end 5' of this exhaust gas receiving piece 5 faces the flow of exhaust gas F as shown in FIG. It has a shape. A large number of cut holes 4 and exhaust gas receiving pieces 5 are formed at predetermined intervals on the circumferential surface of the upstream portion A of the exhaust pipe 1 located on the engine side.

And the hole in the downstream part located on the exhaust side is
When a cut is made from the outside of the exhaust pipe 1, a cut end 6' protruding toward the inside of the pipe is formed in a cut-shaped hole 7 having an exhaust gas outlet piece 6 facing downstream in the flow direction of exhaust gas. There is. This cut hole 7 is
A large number of them are formed at predetermined intervals on the circumferential surface of the downstream portion B located on the exhaust side of the exhaust pipe 1.

In the case of the present invention, the sound deadening material 3 is a stainless steel mesh body 8 made of a dense mesh of thin stainless steel wires (for example, wires like a human hair or slightly thicker than that) as shown in FIG. use
In the diagram, the mesh is shown to be somewhat coarse, but this simplified diagram shows that a more densely meshed stainless steel mesh body 8 is used, and this is filled around the exhaust pipe 1. To do this, it is folded several times and filled in a polymerized state.

According to such a configuration, part of the exhaust gas discharged from the engine passes through the inside of the exhaust pipe 1 and is exhausted to the atmosphere, but most of it passes through the cut-shaped hole 4 in the upstream side A section of the exhaust pipe 1. Passing through
It flows from the inside of the exhaust pipe 1 to the outside, where it is expanded to lower the pressure and temperature, and the sound generated at that time is absorbed into the sound deadening material 3 made of a stainless steel mesh and muffled, and then the downstream side B of the exhaust pipe 1. Through the cut holes 7 in the section, the exhaust gas flows from the outside to the inside guided by the exhaust gas outlet piece 6 and is discharged to the atmosphere. In this process, the present invention exhibits the following features.

That is, in the upstream side A portion of the exhaust pipe 1, a cut hole 4 and an exhaust gas receiving piece 5 are formed.
The cut end 5' of the exhaust gas receiving piece 5 faces the flow of the gas F, and is structured to easily receive the gas F. Therefore, the flowing exhaust gas F is guided by the exhaust gas receiving piece 5 and easily flows into the sound deadening material 3. On the other hand, in the downstream part B of the exhaust pipe 1, a cut-shaped hole 7 and an exhaust gas outflow piece 6 are formed, and the cut end 6' of this exhaust gas outflow piece 6 faces toward the flow of the gas F, thereby reducing noise. The structure allows gas to easily flow out from the material 3 side to the inside of the tube. Therefore, the exhaust gas in the sound deadening material 3 is easily guided by the exhaust gas outlet piece 6 and flows into the exhaust pipe, and is sucked into the gas discharged to the atmosphere through the exhaust pipe 1. The exhaust gas that has flowed into the sound deadening material 3 upstream flows effectively into the exhaust pipe 1.

In this way, in the upstream side A section of the exhaust pipe 1, the exhaust gas is configured to easily flow into the sound deadening material 3, and in the downstream side B section, the exhaust gas is configured to easily exit from the sound deadening material 3 into the pipe. Gas flows into and out of the sound deadening material 3 effectively. Therefore, the pressure drop and temperature drop due to the expansion of the exhaust gas within the muffler are promoted, and the noise generated when the pressure drops at the sound deadening material 3 is effectively suppressed by the sound deadening material 3, thereby absorbing or absorbing the sound. Good sound deadening performance.

In particular, the present invention uses a mesh body 8 made of thin stainless steel wire as the sound deadening material 3.

Therefore, it is less likely to burn due to the high temperature of the exhaust gas, and it will not form into lumps due to burning or deterioration. In the case of conventional short glass fibers, they burn into beads, which provide back pressure when exhaust gas flows out and can cause abnormal noise.
In the case of the present invention, there is no abnormal increase in back pressure, and sound absorption is carried out as originally set. In addition, if moisture in the exhaust gas or moisture mixed in during cleaning with water gets into the sound deadening material 3, conventionally it gets trapped in the layer of short glass fibers and evaporates and condenses repeatedly in the trapped state. However, since the mesh body 8 is made of stainless steel wire, moisture can be easily dissipated to the outside. Therefore, there is no possibility that water will become trapped in the sound deadening material 3.

In addition, in the case of a sound deadening material that is simply densely filled with short stainless steel fibers, there is a risk that each of them will leak out to the outside of the muffler as it is used, and the amount of loose stainless steel fibers tends to gradually increase. However, in the case of the present invention, the stainless steel net body is not simply densely filled with thin stainless steel wires, but is woven into a net shape, so it is not as durable as described above. It has a variety of practical advantages, such as no leakage to the outside of the muffler due to the flow of exhaust gas and excellent durability.

[Brief explanation of the drawing]

The accompanying drawings show an embodiment of the present invention, in which Fig. 1 is a longitudinal side view, Fig. 2 is an enlarged view of the cut hole in the upstream part of the exhaust pipe and the hole in the downstream part, and Fig. 3 is a rear view. Fig. 4 is a simplified perspective view of a stainless steel net made of thin stainless steel wires knitted into a mesh, and Fig. 5 is a longitudinal cross-sectional side view of the prior art.
is an outer pipe, 3 is a sound deadening material, 4 is a cut hole, 5 is an exhaust gas receiving piece, 5' is a cut end, 6 is an exhaust gas outlet piece, 6' is a cut end, 8 is a stainless steel mesh body constituting the sound deadening material, A is the upstream part of the exhaust pipe, and B is the downstream part of the exhaust pipe.

Claims (1)

[Scope of utility model registration request] an exhaust pipe having a plurality of holes formed on its circumferential surface; an outer pipe disposed around the exhaust pipe;
In an automobile muffler made of a sound deadening material housed between these pipes, the hole formed in the exhaust pipe is cut from the outside of the exhaust pipe in the upstream portion located on the engine side. Sometimes, a cut end protruding into the inside of the pipe is formed into a cut-shaped hole with an exhaust gas receiving piece that faces the flow of exhaust gas, and in the downstream part, when the cut is made from the outside of the exhaust pipe, the pipe The cut end protruding inward is formed into a cut-shaped hole having an exhaust gas outlet piece facing downstream in the flow direction of exhaust gas, and the sound deadening material is made of a stainless steel mesh made of thin stainless steel wires knitted in a mesh shape. An automobile muffler characterized by being filled with a body.