JPS6146169Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention mainly relates to an exhaust system for automobiles.

[Conventional technology]

Conventionally, this type of exhaust system has been developed, for example, in the 1980s.
As shown in Japanese Patent No. 28758 or FIG. 1, a pre-muffler 1 and a main muffler 2 are installed in the middle of an exhaust pipe p, and these mufflers 1 and 2 effectively remove noise contained in exhaust gas.

[Problem that the invention attempts to solve]

However, since the above-mentioned exhaust system is provided with a relatively large auxiliary primary muffler 1 in addition to the large main muffler 2, the entire system becomes large and heavy, and it is not easy to mount it on the underfloor surface of the vehicle body. Moreover, it is disadvantageous that it is difficult to provide the pre-muffler 1 at an appropriate position where a sufficient sound-dampening effect can be obtained, resulting in the problem that a sufficient sound-damping effect cannot be achieved.

[Purpose of invention]

The present invention was devised to solve these inconveniences and problems, and allows the device to be made smaller and lighter.
It is an object of the present invention to provide an exhaust device that is easy to attach to the underfloor surface of a vehicle body and can be expected to have a sufficient noise reduction effect.

[Means for solving problems]

In order to achieve this purpose, the present invention branches any part of the exhaust pipe into two pipes that are partially in close contact with each other, closes both ends of one pipe, fills the inside of the pipe with sound absorbing material, and closes the ends of the other pipe. An opening in which a metal net or a foamed metal plate is stretched is provided in the peripheral wall that is in close contact with the pipe, and one or more through holes with a smaller diameter than the opening are bored in the peripheral wall of the close contact part of the other pipe. It is characterized by the presence of

[Effect of invention]

According to the present invention, when there is one through hole, the tube filled with sound absorbing material acts as a resonator and exhibits a resonance damping effect, and when there are multiple through holes, the tube acts as a branch. It has an interference damping effect and reduces exhaust noise.

[Example of idea]

Embodiments of the present invention will be described in detail below with reference to FIGS. 2 to 5.

FIG. 2 shows an embodiment of the exhaust system according to the present invention.

The exhaust pipe p has a manifold 3 that is directly connected to the engine, and a front exhaust pipe 4 that becomes a single pipe toward the rear from there, and an arbitrary part of the exhaust pipe p that branches into two pipes. It consists of pipes 5 and 6, and an integrated rear exhaust pipe 7 with the end of the exhaust pipe branched into two pipes. One pipe 5 branched into the two pipes
As shown in FIG. 4, both ends of the tube are closed with plugs 8, and the sealed tube is filled with a sound absorbing material 9 such as glass wool or stainless steel wool. The other branched tube 6 is a hollow tube. These two tubes 5 and 6 are brought into close contact with each other in the central part, and an opening 11 formed in the contact part 10
a and through hole 11b.

Note that the resonance characteristics of the tube 5 are greatly influenced by the capacity of the tube 5 and the diameter of the through hole 11b.
In order to ensure that the tubes 5 and 6 can be assembled in such a way that they can flow in the close contact portion 10, when the resonance characteristics are changed by changing the hole diameter of the hole 10, the opening 11 is
A is formed with a larger opening than the through hole 11b.

Further, a metal net (a foamed metal plate may be used) 12 is stretched over the opening 11a to prevent the sound absorbing material 9 filled in the tube 5 from scattering. These branched pipes 5 and 6 are integrated, and the inlet side is fitted into the enlarged pipe part 4a at the end of the front exhaust pipe 4, as shown in FIG. Fits into the tube expanded portion 7a at the tip, and connects one tube 5.
becomes a resonant tube filled with sound absorbing material 9, and the other tube 6
is the main exhaust pipe.

The exhaust system according to this embodiment has such a configuration, and the exhaust noise discharged from the engine passes through the front exhaust pipe 4 to the pipe 6 which is the main exhaust pipe, and then from the pipe 6 to the rear side. It passes through the exhaust pipe 7 and is discharged from the end of the rear exhaust pipe 7 by branching into two. When the exhaust noise propagates inside the pipe 6, the resonance damping effect of the pipe 5 attached to the pipe 6 as a resonator and the damping effect due to the sound absorption effect of the sound absorbing material 9 filled in the pipe 5 are combined. , the exhaust noise is further reduced and is discharged outside the exhaust pipe p.

With such an exhaust system, since the exhaust pipe itself is provided with a resonance pipe filled with a sound absorbing material, there is no need to provide two large mufflers on the exhaust pipe, and the entire system can be made smaller and lighter. In addition, since the pipes 5 and 6 having a noise-reducing function can be easily and appropriately bent according to the underfloor surface of the vehicle body, the device can be easily installed on the underfloor surface of the vehicle body. Furthermore, since these pipes 5 and 6 can be provided at any appropriate position on the exhaust pipe p, a sufficient sound-dampening effect can be expected from this point as well.

Moreover, in this embodiment, since the opening 11a is provided to be larger than the through hole 11b, even when the resonance characteristics of the tube 5 are changed by changing the hole diameter of the through hole 11b, the tube can be easily adjusted. 5 and the pipe 6 are now assembled through the close contact part 10 so that they can flow. Moreover, since the metal mesh 12 is stretched over the large opening 11a, the sound absorbing material 9 filled in the tube 5 will not be scattered.

In the above embodiment, the sound absorbing material 9 is provided in the exhaust pipe p.
Although an example has been given in which one tube 5 serving as a resonant tube filled with . Note that the means for closing both ends of the tube 5 is not limited to the stopper 8, but may be a structure in which both ends of the tube 5 are closed by crimping means, as shown in FIG. 5.

Further, in the above embodiment, a case has been described in which the tube 5 is used as a resonator, but if a plurality of through holes 11b are provided, the tube 5 can be used as a branch. In this case, the exhaust noise of a specific frequency due to the branch can be attenuated by the interference effect.

Although the present invention is mainly used as an exhaust system for automobiles, it can of course be effectively used not only as an exhaust system for automobiles but also as an exhaust system for other vehicles.

[Effect of idea]

As described above, according to the present invention, since the exhaust pipe itself has a silencing function, there is no need to provide multiple large mufflers, and as a result, the entire device can be made smaller and lighter. In addition, since it is a tube, it can be bent easily and appropriately according to the underside of the car body, making it extremely easy to attach to the underside of the car body. In addition,
Since the pipe having a silencing function, particularly the close contact portion connecting the pipe to the exhaust pipe, can be provided at any appropriate position on the exhaust pipe, a sufficient silencing effect can be obtained. Furthermore, even if the hole diameter of the through hole of the other tube drilled in the above-mentioned close contact portion is changed in order to change the resonance characteristics of the tube having the silencing function, the opening of the tube having the silencing function will be smaller than the through hole. Since the pipes also have large openings, it is easy to fit the two pipes together and assemble them. Moreover, since the sound-dampening effect due to the resonance of the closed tube and the sound-dampening effect due to the sound-absorbing material filled therein combine to muffle the sound, an even greater sound-damping effect can be expected.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional exhaust system, FIG. 2 is a partial cross-sectional perspective view of an embodiment of the exhaust system according to the present invention, and FIG. 3 is an exploded perspective view of essential parts of the exhaust system shown in FIG. , FIG. 4 is a sectional view of a main part of the exhaust system shown in FIG. 2, and FIG. 5 is a perspective view of a main part showing one end of one pipe of another embodiment of the present invention. 1, 2...muffler, 4...front exhaust pipe, 5,
6... Branched pipe, 7... Rear exhaust pipe, 9...
Sound absorbing material, 10...adhesive part, 11a...opening part, 1
1b...through hole, 12...metal mesh, p...exhaust pipe.

Claims (1)

[Scope of utility model registration request] Branch any part of the exhaust pipe into two pipes that are in close contact with each other, close both ends of one pipe, fill the pipe with sound absorbing material, and install a metal mesh or foam metal plate on the peripheral wall that is in close contact with the other pipe. 1. An exhaust device characterized in that an opening is provided, and one or more through holes having a smaller diameter than the opening are bored in the peripheral wall of the close-contact portion of the other pipe.