JP2001214729A - Exhaust silencer for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure gastightness between a supporting hole formed in a baffle inside a muffler for supporting the tail tube and a tail tube by forming the supporting hole into a round shape capable of being easily machined and ensuring strength near the supporting hole. SOLUTION: This exhaust silencer for an automobile comprises a tail tube 205, partitioned by a partition panel 206 into a first passage 203 where exhaust gas led from an inlet tube 200 to a first volume chamber 103 in the muffler 100 flows in and a second passage 204 where the exhaust gas in the volume chamber 103 flows from a third volume chamber 105 connected through pass tubes 201, 202, inside the muffler 100. The tail tube 205 penetrates the muffler 100 from the third volume chamber 105, and comprises a section at which tip parts 203e, 204e of the first passage 203 and the second passage 204 in the volume chamber 105, respectively, become the same length. The first passage 203 is blocked to the volume chamber 105 by a cap 207 and provided with an opening part 203p in a side surface for communicating to the volume chamber 103, and the tip part 204e of the second passage 204 is opened to the volume chamber 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a first flow path into which exhaust gas from an engine guided from an inlet tube to a first volume chamber inside a muffler flows, and a path through which the exhaust gas from the first volume chamber passes. An exhaust muffler for automobiles, comprising a tail tube partitioned by a partition plate with a second flow path flowing from the most downstream volume chamber among other volume chambers connected via a tube, inside the muffler. It is about.

[0002]

2. Description of the Related Art Conventional exhaust silencers for automobiles include:
For example, there is one disclosed in Japanese Patent Application No. 10-352370. Such a device is provided with a plurality of mufflers provided in the muffler according to the exhaust gas pressure for the purpose of reducing exhaust noise at low engine speed, reducing exhaust noise at high engine speed, and reducing exhaust loss. This is a device that exhausts gas using a flow path.

FIG. 7 is a cross-sectional view showing a conventional exhaust muffler for an automobile. The muffler 10 has a first volume chamber 13, a second volume chamber 14, and a third volume chamber 15 partitioned by two baffles 11, 12. Muffler 10
The first flow path 23 into which exhaust gas from an engine (not shown) guided from the inlet tube 20 to the first volume chamber 13 flows, and the exhaust gas in the first volume chamber 13 passes through the pass tubes 21 and 22. Other volume chambers 14, 1 connected via
5, a tail tube 25 partitioned into a second flow path 24 flowing from the third volume chamber 15 at the most downstream position.

The first flow path 2 constituting the tail tube 25
Each of the third and second flow paths 24 has a half-moon shaped cross section as shown in FIG. As shown in FIG.
In order to make the first volume chamber 13 communicate with the outside, the tip 23e is supported by penetrating only one baffle 12, while the second flow path 24 makes the third volume chamber 15 communicate with the outside. , The tip 24e of which has two baffles 11, 1
2 and supported. In this case, tail tube 2
In order to support the baffle 5 with the baffles 11 and 12, burring is performed on the baffles 11 and 12 to form support holes corresponding to the shapes of the first flow path 23 and the second flow path 24 that constitute the tail tube 25. I do.

[0005]

However, when forming a semi-lunar burring hole in the baffle 11 in order to penetrate the second flow path 24, both ends of the bottom of the semi-moon have an acute angle. Because it is difficult to form cracks and burring holes into accurate half-moon shapes,
There is a problem that it is difficult to secure airtightness between the burring hole and the tail tube 25, in this case, the second flow path 24.

That is, the first and sixth aspects of the present invention have been made in view of the above-mentioned facts, and a supporting hole formed in a baffle for supporting a tail tube is easily machined. It is another object of the present invention to secure the airtightness between the support hole and the tail tube by forming the support hole into a circular shape capable of securing the strength around the support hole.

The second and sixth aspects of the present invention are directed to securely closing the distal end of the tail tube.

Further, claims 3 and 4 and claims 8 and 9
The third and fourth inventions and the eighth and ninth inventions according to the present invention aim to securely close the tip of the tail tube without adding a new part.

According to the fifth and tenth aspects of the present invention, the tail tube is constructed by using inexpensive and simple means the exhaust gas from the engine from the volume chamber existing in the middle of the tail tube. It is intended to flow into one of the flow paths.

[0010]

According to a first aspect of the present invention, there is provided a vehicle exhaust silencer according to a first aspect of the present invention, wherein exhaust gas from an engine led from an inlet tube to a first volume chamber inside a muffler flows. One partition and a second flow path into which the exhaust gas of the first volume chamber flows in from the volume chamber at the most downstream position among other volume chambers connected via a pass tube are partitioned by a partition plate. In the exhaust muffler for automobiles having a tail tube inside the muffler, the tail tube penetrates through the muffler from the most downstream position volume chamber, and the first flow path and the second flow path in the most downstream position volume chamber. The two flow paths have a cross section in which the distal ends have the same length, and the first flow path is closed at the distal end with respect to the volume chamber at the most downstream position, and the first volume chamber is provided on the side surface thereof. Opening to communicate with Is provided, also, the tip portion of the second flow path, the is characterized in that it is open to the most downstream position volume chamber.

According to a second aspect of the present invention, there is provided an exhaust muffler for a vehicle according to the first aspect, wherein a distal end portion of the first flow path in the volume chamber at the most downstream position is closed by a cap. Is what you do.

According to a third aspect of the present invention, there is provided an exhaust muffler for a vehicle according to the first aspect, wherein a front end of the first flow path in the volume chamber at the most downstream position is closed by crushing. It is assumed that.

According to a fourth aspect of the present invention, there is provided a vehicle exhaust silencer according to the fourth aspect, wherein the crushing is performed by
It is characterized by crimping crushed by picking up the tube surface.

According to a fifth aspect of the present invention, there is provided a vehicle exhaust silencer according to any one of the first to fourth aspects, wherein the opening has a porous shape formed by an aggregate of a plurality of holes. It is characterized by having.

According to a sixth aspect of the present invention, there is provided a vehicle exhaust silencer according to a sixth aspect of the present invention, wherein: a first flow path through which exhaust gas from an engine led from an inlet tube to a first volume chamber inside a muffler flows; A tail tube partitioned by a partition plate into a second flow path into which exhaust gas from the first volume chamber flows in from a volume chamber located at the most downstream position among other volume chambers connected via a pass tube is used as the muffler. In the automobile exhaust silencer provided inside, the tail tube is the first tube.
The first flow path and the second flow path in the first volume chamber have a cross section having the same length. First
The second flow path is open to the volume chamber, and the second flow path is closed at its tip with respect to the first volume chamber, and has an opening on the side surface for communicating with the most downstream position volume chamber. A part is provided.

According to a seventh aspect of the present invention, in the exhaust gas muffler for a vehicle according to the seventh aspect, in the sixth aspect, a tip of the second flow path in the chamber at the most downstream position is closed by a cap. It is assumed that.

According to an eighth aspect of the present invention, in the exhaust muffler for an automobile according to the eighth aspect, in the sixth aspect, the distal end of the second flow path in the volume chamber at the most downstream position is closed by crushing. It is a feature.

According to a ninth aspect of the present invention, in the exhaust exhaust silencer for a vehicle according to the ninth aspect, in the eighth aspect, the crushing is performed by:
It is characterized by crimping crushed by picking up the tube surface.

According to a tenth aspect of the present invention, there is provided a vehicle exhaust silencer according to any one of the sixth to ninth aspects, wherein the opening has a porous shape formed by an aggregate of a plurality of holes. It is characterized by being.

[0020]

According to the first aspect of the present invention, in the vehicle exhaust silencer, the tail tube is connected to the muffler from the most downstream volume chamber among other volume chambers connected to the first volume chamber via a pass tube. The first flow path and the second flow path in the volume chamber penetrating through the inside have a cross section in which the distal ends of the first flow path and the second flow path have the same length. An opening for communicating with the first volume chamber is provided on a side surface thereof while being closed with respect to the volume chamber, and a tip end of the second flow path is provided with respect to the most downstream position volume chamber. Open.

Therefore, the exhaust gas from the engine guided from the inlet tube to the first volume chamber inside the muffler flows through an opening provided on the side surface of the first flow path communicating with the first volume chamber. , Is discharged outside the muffler. Further, when the pressure of the exhaust gas increases, the exhaust gas in the first volume chamber flows into the most downstream volume chamber connected via the pass tube, and opens to the most downstream volume chamber. From the end of the second flow path, which is discharged outside the muffler.

In this case, since the tail tube has a cross section in which the end portions of the first flow path and the second flow path have the same length, the shape of the support hole formed in the baffle for supporting the tail tube is provided. Can be formed in a circular shape, so that the processing of the support hole is relatively easy, and even during the processing, a crack is hardly generated around the support hole.

Therefore, according to the first aspect, the support hole formed in the baffle for supporting the tail tube has a circular shape that can be easily processed and has sufficient strength around the support hole. And the airtightness of the tail tube can be secured.

Further, in the exhaust muffler for a vehicle according to the second invention, in the first invention, since the tip of the first flow path in the tail tube is closed by a cap, the first flow path of the first flow path is closed. The tip can be securely closed.

Further, in the exhaust exhaust silencer for a vehicle according to the third invention, in the first invention, the end of the first flow path in the tail tube is closed by crushing, so that the first flow path is closed. The end of the first flow path can be reliably closed without adding a new part for closing the end of the first flow path.

[0026] In addition, in the exhaust muffler for a vehicle according to the fourth invention, in the third invention, the crushing process is a crimping process which is crushed by picking up a tube surface. Can be used, and a process for securely closing the front end of the first flow path is easy and inexpensive.

According to a fifth aspect of the present invention, there is provided an exhaust muffler for an automobile according to any one of the first to fourth aspects, wherein the opening has a porous shape formed by an aggregate of a plurality of holes. Therefore, the exhaust gas from the engine is directly supplied from the first volume chamber existing in the middle of the tail tube by the inexpensive and simple processing.
It can be made to flow into a flow path.

According to a sixth aspect of the present invention, in the vehicle exhaust silencer, the tail tube penetrates through the muffler from the first volume chamber, and a tip of the first flow path and the second flow path in the first volume chamber. Have sections of the same length,
The front end of the first flow path is open to the first volume chamber, and the second flow path is closed at the front end with respect to the first volume chamber, and is provided on a side surface thereof. Is provided with an opening for communicating with the volume chamber at the most downstream position.

For this reason, the exhaust gas from the engine guided from the inlet tube to the first volume chamber inside the muffler flows into the distal end of the first flow path opened to the first volume chamber. , Is discharged outside the muffler. further,
When the pressure of the exhaust gas increases, the exhaust gas in the first volume chamber flows into the most downstream volume chamber connected via the pass tube, and the second flow path communicates with the most downstream volume chamber. Is discharged to the outside of the muffler through an opening provided on the side surface of the muffler.

In this case, since the tail tube has a cross-section in which the first flow path and the second flow path have the same length, the shape of the support hole formed in the baffle for supporting the tail tube is provided. Can be formed in a circular shape, so that the processing of the support hole is relatively easy, and even during the processing, a crack is hardly generated around the support hole.

According to the sixth aspect of the present invention, the support hole formed in the baffle for supporting the tail tube has a circular shape that can be easily processed and has sufficient strength around the support hole. And the airtightness of the tail tube can be secured.

[0032] Further, according to the seventh aspect of the present invention, in the vehicle exhaust silencer according to the sixth aspect of the present invention, since the tip of the second flow path in the tail tube is closed by a cap, The tip can be securely closed.

Further, in the exhaust muffler for an automobile according to an eighth aspect of the present invention, in the sixth aspect of the present invention, the tip of the second flow path in the tail tube is closed by crushing, so that the second flow path is closed. It is possible to achieve a reduction in the number of parts and a reduction in the number of parts without adding a new part in order to close off the tip of the.

[0034] In addition, in the automobile exhaust silencer according to the ninth invention, in the above-mentioned eighth invention, the crushing process is a crimping process which is crushed by picking up a tube surface. Can be used, and a process for securely closing the front end of the second flow path is easy and inexpensive.

According to a tenth aspect of the present invention, there is provided an exhaust muffler for an automobile according to any one of the sixth to ninth aspects, wherein the opening has a porous shape formed by an aggregate of a plurality of holes. Therefore, the exhaust gas from the engine can be made to flow into the second flow path constituting the tail tube directly from the lowermost volume chamber located in the middle of the tail tube by an inexpensive and simple processing.

[0036]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of a vehicle exhaust silencer according to the present invention, and FIG.
FIG. 2 is a sectional view taken along line AA of FIG.

The muffler 100 has therein a first volume chamber 103, a second volume chamber 104, and a third volume chamber 105 partitioned by two baffles 101 and 102. Muffler 1
00 is the first volume chamber 10 from the inlet tube 200.
The first flow path 203 into which exhaust gas from an engine (not shown) led to the third flow path 3 flows, and the second flow path 203 in which the exhaust gas in the first volume chamber 103 is connected via pass tubes 201 and 202.
A tail tube 205 partitioned by a partition plate 206 is provided in the inside of the volume chamber 104 and the second flow path 204 flowing from the third volume chamber 105 located at the most downstream position in the third volume chamber 105.

The first chamber 103 located at the center of the muffler 100 is connected to the second chamber 10 via a pass tube 201.
4 and the second volume chamber 104 is connected to the third volume chamber 105 via the pass tube 202. An opening / closing valve 202V for closing the third volume chamber 105 side by an urging force of a spring (not shown) or the like is provided at an end of the pass tube 202 on the third volume chamber 105 side.
When the exhaust gas in the pass tube 202 exceeds a predetermined pressure, 02V opens the third volume chamber 105 side against the urging force as shown in FIG.

The tail tube 205 is a baffle 10
The support holes 101p and 102p formed in the first and second support holes 102p are formed by, for example, punching by burring. The tail tube 205 penetrates through the muffler 100 from the third volume chamber 105, and the first flow path 203 and the second flow path 204 forming the tail tube 205 are respectively
Although the partition plate 206 has a half-moon-shaped cross section as shown in FIG. 2, the tail tube 205 includes a first flow path 203 and a second flow path 20 in the third volume chamber 105.
4 have cross sections of the same length.

In the first flow path 203, a tip 203 e in the third volume chamber 105 is closed by the cap 207 with respect to the third volume chamber 105, and a side surface thereof communicates with the first volume chamber 103. Opening 203p is provided for connecting the first volume chamber 103 to the outside.

In this case, the first flow path 203 is
07, the third volume chamber 105 is closed, so that the front end 203e of the first flow path 203 can be reliably closed. Further, the opening 203p provided on the side surface of the first flow path 203 is preferably a porous shape formed by an aggregate of a plurality of holes. In this case, the exhaust gas from the engine is removed from the tail tube 205 by inexpensive and simple processing.
Can flow directly into the first flow path 203 constituting the tail tube 205 from the first volume chamber 103 existing in the middle of the above.

The second flow path 204 has a distal end 204e in the third volume chamber 105, which opens to the third volume chamber 105, and connects the third volume chamber 105 to the outside.

Here, the operation of the present embodiment will be described.

Exhaust gas from an internal combustion engine such as an engine is guided from the inlet tube 200 to the first volume chamber 103. The exhaust gas in the first volume chamber 103 first flows in through an opening 203p provided on the side surface of the first flow path 203 communicating with the first volume chamber 103, and the exhaust gas flows out of the muffler 100 only from the first flow path 203. That is, it is discharged to the atmosphere. In this case, the first flow path 20 with respect to the first volume chamber 103
Since the expansion ratio of 3 is ensured, the exhaust noise in the low frequency range, which is the main component in the low engine speed range where the exhaust gas flow rate is small, can be sufficiently suppressed.

When the pressure of the exhaust gas rises, the pressure of the exhaust gas flowing into the second volume chamber 104 from the pass tube 201 becomes stronger against the urging force of the on-off valve 202V.
On the other hand, the exhaust gas flows into the front end portion 204 e of the second flow passage 204 opened to the third volume chamber 105, in addition to the first flow passage 203. It is discharged to the outside of the muffler 100, that is, to the atmosphere. in this case,
It is possible to significantly reduce exhaust loss and airflow noise in the middle and high engine speed regions where the exhaust gas flow rate is large.

In the case of this embodiment, the tail tube 205
The tip 20 of the first channel 203 and the second channel 204
Since 3e and 204e have the same length in cross section, the baffles 101 and 1 support the tail tube 205.
Since the burring holes 101p and 102p formed in the burring hole 02 can be made circular, the burring holes 1p and 102p can be made circular.
Processing of 01p and 102p is relatively easy, and even during processing, cracks are less likely to occur around the burring holes 101p and 102p.

Therefore, according to the present embodiment, the burring holes 101p and 102p formed in the baffles 101 and 102 for supporting the tail tube 205 can be easily processed, and the strength around these burring holes 101p and 102p can be reduced. Since the burring holes 101p and 102p and the tail tube 205 have a circular shape that can be secured, airtightness can be secured between the burring holes 101p and 102p and the tail tube 205.

FIG. 3 is a sectional view showing a second embodiment of the exhaust silencer for a vehicle according to the present invention, and FIG.
FIG. 4 is a perspective view showing a tip portion of a tail tube in FIG. 3.
1 and 2 are denoted by the same reference numerals and description thereof is omitted.

The basic structure of the second embodiment is the same as that of the first embodiment.
First chamber 1 partitioned by two baffles 101 and 102
03, a second volume chamber 104, and a third volume chamber 105, and a tail tube 205 partitioned by a partition plate 206 into a first channel 203 and a second channel 204 is provided therein.

Similarly to the first embodiment, the tail tube 205 is supported by burring holes 101p and 102p formed in the baffles 101 and 102, and the third volume chamber 1
05 through the muffler 100 and the tail tube 2
The first flow path 203 and the second flow path 204 constituting the first flow path
And the front-end | tip part 203e, 204e of the 2nd flow path 204 becomes a cross section of the same length.

Exhaust gas from an internal combustion engine such as an engine is guided from the inlet tube 200 to the first volume chamber 103. First, the exhaust gas in the first volume chamber 103 flows into the opening 203p provided on the side surface of the first channel 203 communicating with the first volume chamber 103, and the exhaust gas is exhausted to the atmosphere only from the first channel 203. You.

When the pressure of the exhaust gas rises, the pressure of the exhaust gas flowing from the pass tube 201 into the second volume chamber 104 becomes stronger against the urging force of the on-off valve 202V.
On the other hand, the exhaust gas flows into the front end portion 204 e of the second flow passage 204 opened to the third volume chamber 105, in addition to the first flow passage 203. Released to the atmosphere.

In the present embodiment, the first flow path 203 is the third flow path.
An end portion 203e in the volume chamber 105 is closed by a crushing process with respect to the third volume chamber 105, and an opening for communicating with the first volume chamber 103, that is, an aggregate of a plurality of holes is provided on a side surface thereof. Porous part 203p formed by
Is provided, and the second flow path 204 is provided in the third volume chamber 10.
5 is open to the third volume chamber 105 to allow the first volume chamber 103 and the third volume chamber 105 to communicate with the outside.

Therefore, according to the present invention, the first flow path 203
Since the distal end portion 203e in the third volume chamber 105 is sealed off from the third volume chamber 105 by the crushing process, in addition to the operation and effect of the first embodiment, a new portion is provided for closing the distal end portion 203e. It is possible to reduce the weight due to the reduction in the number of parts without adding any additional parts. In particular, as shown in FIG. 4, if the above-mentioned crushing is crimping crushed by picking up the surface of the tube 205, an existing crimping device can be used, and the first flow path 2 can be used.
A process for securely closing the distal end portion 203e of the 03 is easy and inexpensive.

FIG. 5 is a sectional view showing a third embodiment of the vehicle exhaust silencer according to the present invention. In addition, FIG.
2 are denoted by the same reference numerals and description thereof is omitted.

The muffler 100 has a first volume chamber 103, a second volume chamber 104, and a third volume chamber 10 partitioned by two baffles 101 and 102, similarly to the above embodiment.
5, the first volume chamber 1 of the first and second embodiments.
03 and the third volume chamber 105 are arranged in reverse.
Similar to the first and second embodiments, the muffler 100 has a first flow path 203 into which exhaust gas from an engine (not shown) guided from the inlet tube 200 to the first volume chamber 103 flows, and a first volume 203. The exhaust gas in the chamber 103 is connected to the second volume chamber 10 via the pass tubes 201 and 202.
4, the partition plate 206 is provided between the third flow chamber 204 and the second flow path 204 which flows in from the third downstream volume chamber 105 in the third downstream volume chamber 105.
A tail tube 205 partitioned by is provided inside.

The first volume chamber 103 located on the input side of the muffler 100 is connected to the second volume chamber 104 located on the output side via a pass tube 201 penetrating through the third volume chamber 105, The chamber 104 includes a pass tube 202
Through the third volume chamber 10 located at the center of the muffler 100
5 is connected. Third volume chamber 10 of pass tube 202
An opening / closing valve 202V that closes the third volume chamber 105 side by an urging force of a spring (not shown) or the like is provided at the end on the fifth side.
When the exhaust gas in the chamber exceeds a predetermined pressure, as shown in FIG. 5, the third volume chamber 105 side is opened against the urging force.

The tail tube 205 is a baffle 10
The support holes 101p and 102p formed in the first and second support holes 102p are formed by, for example, punching by burring. Further, the tail tube 205 penetrates through the inside of the muffler 100 from the first volume chamber 103, and the first flow path 203 and the second flow path 204 constituting the tail tube 205 are respectively
The partition tube 206 has a half-moon-shaped cross-section, but the tail tube 205 has a distal end portion 203 of the first channel 203 and the second channel 204 in the first volume chamber 103.
e and 204e are sections of the same length.

The first flow path 203 has a distal end 203e in the first volume chamber 103, which opens to the first volume chamber 103, and connects the first volume chamber 103 to the outside.

The second flow path 204 is configured such that a tip portion 204 e in the third volume chamber 103 is closed by the cap 209 in the first volume chamber 1.
03, and an opening 204p for communicating with the third volume chamber 105 is provided on the side surface thereof.
The third volume chamber 105 is communicated with the outside.

In this case, the second flow path 204 is
09, the first volume chamber 103 is closed, so that the front end 204e of the second flow path 204 can be reliably closed. The second flow path 204 is provided in the third volume chamber 1.
It is also possible that the tip portion 204e in 05 is closed to the third volume chamber 105 by crushing. In this case, similarly to the operation and effect of the second embodiment, the distal end portion 204e
Without adding new parts to block off the second
The front end portion 204e of the flow path 204 can be reliably closed. In particular, if the crushing process is the crimping process as shown in FIG. 4, an existing crimping device can be used, and the process for securely closing the distal end portion 204 e of the second flow path 204 can be easily performed. And inexpensive.

The opening 204p provided on the side surface of the second flow path 204 is preferably a porous shape formed by an aggregate of a plurality of holes. In this case, the exhaust gas from the engine can be made to flow directly from the third volume chamber 105 located in the middle of the tail tube 205 into the second flow path 204 constituting the tail tube 205 by inexpensive and simple processing.

Here, the operation of the present embodiment will be described.

Exhaust gas from an internal combustion engine such as an engine is guided from the inlet tube 200 to the first volume chamber 103. The exhaust gas in the first volume chamber 103 first flows into the distal end 203e of the first flow path 203 that is open to the first volume chamber 103, and the exhaust gas flows only from the first flow path 203 to the outside of the muffler 100. That is, it is discharged to the atmosphere.

In this case, the first volume 103
Since the expansion ratio of the flow path 203 is ensured, the exhaust noise in the low frequency range, which is the main component in the low engine speed range where the exhaust gas flow rate is low, can be sufficiently silenced. Since it can be secured longer than in the first and second embodiments, when the open / close valve 202V is closed, the low-frequency sound can be further muted.

When the pressure of the exhaust gas increases, the pressure of the exhaust gas flowing from the pass tube 201 into the second volume chamber 104 becomes stronger against the urging force of the on-off valve 202V.
The exhaust gas flows into the opening 204p provided on the side surface of the second flow path 204 communicating with the third volume chamber 105, in addition to the first flow path 203, and the exhaust gas flows from the second flow path 204 as well. It is discharged to the outside of the muffler 100, that is, to the atmosphere. In this case, the exhaust loss and the airflow noise in the middle and high engine speed regions where the exhaust gas flow rate is large can be significantly reduced.

FIG. 6 is a sectional view showing a fourth embodiment of a vehicle exhaust silencer according to the present invention. In addition, FIG.
2 are denoted by the same reference numerals and description thereof is omitted.

In this embodiment, the partition plate 206 of the tail tube 205 of the first embodiment is set short, and the first flow path 20
Region 20 before opening third and second flow paths 204 to the atmosphere
By merging at 5R, the exhaust gas flowing through both is interfered.

In this case, in the process in which the on-off valve 202V changes from the fully closed state to the fully opened state, the exhaust noise discharged from the first flow path 203 and the second flow path 204 has an opposite phase relationship in the region R. Since they interfere with each other, exhaust noise can be further reduced. Note that the shape of the partition plate 206 in this embodiment may be adopted in the tail tube of the second or third embodiment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a vehicle exhaust silencer according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing a crimped portion of FIG. 3;

FIG. 5 is a sectional view showing a third embodiment of the present invention.

FIG. 6 is a sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a conventional automobile exhaust silencer.

FIG. 8 is a sectional view taken along line BB of FIG. 7;

[Explanation of symbols]

 100 Muffler 101, 102 Baffle 101p, 102p Burring hole 103 First volume chamber 104 Second volume chamber 105 Third volume chamber 200 Inlet tube 201, 202 Pass tube 202V open / close valve 203 First channel 203e Tip (first channel) ) 203p opening (first flow path) 204 second flow path 204e tip (second flow path) 204p opening (second flow path) 205 tail tube 206 partition plate 207 cap (first flow path) 208 crimping Part 209 cap (second flow path)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazushige Maeda 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Masaomi Fukuhara 5--24-15 Minamidai, Nakano-ku, Tokyo Cal Sonic shares In-company (72) Inventor Seiichi Nitta 5-24-15 Minamidai, Nakano-ku, Tokyo Calsonic Corporation F-term (reference) 3G004 AA01 CA11 DA09 DA24 GA00

Claims (10)

[Claims] 1. A first flow path into which exhaust gas from an engine led from an inlet tube into a first volume chamber inside a muffler is connected to an exhaust gas in the first volume chamber via a pass tube. In the exhaust muffler for automobiles, which has a tail tube partitioned by a partition plate with a second flow path flowing from the most downstream volume chamber among the other volume chambers inside the muffler, The first flow path has a cross-section that penetrates through the muffler from the most downstream position volume chamber, and in which the first flow path and the second flow path have the same length in the most downstream position volume chamber. Has a distal end portion closed with respect to the most downstream position volume chamber, and an opening for communicating with the first volume chamber is provided on a side surface thereof;
An exhaust muffler for an automobile, wherein a front end of the second flow path is open to the volume chamber at the most downstream position. 2. The vehicle exhaust silencer according to claim 1, wherein a tip of the first flow path in the tail tube is closed by a cap. 3. The exhaust muffler for an automobile according to claim 1, wherein a tip portion of the first flow path in the tail tube is closed by crushing. 4. The exhaust muffler for an automobile according to claim 3, wherein the crushing process is a crimping process performed by squeezing a tube surface. 5. The vehicle exhaust silencer according to claim 1, wherein the opening has a porous shape formed by an aggregate of a plurality of holes. 6. A first flow path into which exhaust gas from an engine led from an inlet tube to a first volume chamber inside the muffler flows, and the exhaust gas in the first volume chamber is connected via a pass tube. In the exhaust muffler for automobiles, which has a tail tube partitioned by a partition plate with a second flow path flowing from the most downstream volume chamber among the other volume chambers inside the muffler, A first section of the muffler that penetrates through the muffler from the first volume chamber and has a cross section in which the first flow path and the second flow path have the same length in the first volume chamber; The portion is open to the first volume chamber, and the second flow path has a distal end portion closed with respect to the first volume chamber and has a side surface at the most downstream position volume chamber. Opening for communication with Vehicle exhaust muffler characterized and. 7. The exhaust muffler for an automobile according to claim 6, wherein a tip portion of the second flow path in the tail tube is closed by a cap. 8. The exhaust muffler for an automobile according to claim 6, wherein a tip portion of the second flow path in the tail tube is closed by crushing. 9. The exhaust muffler for an automobile according to claim 8, wherein the crushing process is a crimping process performed by squeezing a tube surface. 10. The device according to claim 6, wherein the opening has a porous shape formed by an aggregate of a plurality of holes.
An automobile exhaust silencer according to any one of claims 1 to 9.