JP2002364332A - Vehicular exhaust muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular exhaust muffler capable of setting up a finisher without impairing appearance and receiving a limitation on layout, and reducing the generation of gas flow noise even when turbulent flow occurs in exhaust gas. SOLUTION: This vehicular exhaust muffler comprises a tail pipe 11 having an inlet opening end 11a set in side a muffler exterior shell and leading exhaust gas flowing in from the inlet opening end 11a to the outside of the muffler exterior shell, and a finisher 12 coupled to the tail pipe 11 and having an outlet opening end 12b that is larger in diameter than a tail pipe and set on the outside of the muffler exterior shell. A coupling portion A1 of the tail pipe 11 and the finisher 12 is set in the muffler exterior shell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of exhaust mufflers for vehicles, such as automobiles, in which a finisher is connected to a tail pipe for leading exhaust gas to the outside of the muffler.

[0002]

2. Description of the Related Art Conventionally, a technique disclosed in Japanese Utility Model Publication No. 63-6420 is known as an exhaust muffler for a vehicle in which a finisher is connected to a tail pipe for leading exhaust gas to the outside of the muffler.

In this conventional publication, as shown in FIG. 6, a finisher is connected to a tail pipe that leads exhaust gas from an exhaust muffler (not shown) to the outside of the muffler. The finisher is connected to the tail pipe by integrally forming an inwardly protruding clamp projection on the small-diameter front end of the finisher and, in cooperation with the clamp projection, a clamp screw capable of clamping the tail pipe outer peripheral surface. It is screwed. A center plate is provided on the inner surface of the rear end with a large diameter to open a support hole fitted and supported by the rear end of the tail pipe. With this coupling structure, the finisher can be reliably supported concentrically on the tail pipe, and the appearance is good and the commercial value can be enhanced.

[0004]

However, the conventional exhaust muffler for a vehicle has the following problems. (Problem 1) This is a connection that fixes the finisher to the tail pipe with a clamp screw, and the connection portion is exposed to the outside. Therefore, the clamp screw and the tail pipe between the silencer body and the finisher can be seen. That is, the appearance is spoiled. (Problem 2) Since the finisher is attached to the tail pipe with two points of the clamp screw and the positioning stay plate for receiving the tail end of the tail pipe, the finisher cannot be set for an extremely short tail pipe due to its structure. . In addition, there are many layout problems as causes of the tail pipe becoming short, for example, when it is desired to shorten the overhang on the rear side of the vehicle or when the main muffler is disposed at the rear end of the vehicle. . (Problem 3) Since the opening of the finisher is arranged immediately behind the rear end of the tail pipe, airflow noise and abnormal noise may be generated from the rear end of the tail pipe, or the tail pipe may be closed. The discharged exhaust gas flow interferes with the curl portion and the edge portion of the opening of the finisher, thereby generating airflow noise and abnormal noise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to set a finisher without impairing the appearance and without being restricted by layout. It is another object of the present invention to provide a vehicle exhaust silencer that can reduce generation of airflow noise even when turbulence occurs in exhaust gas.

[0006]

To achieve the above object, according to the first aspect of the present invention, an inlet opening end is set in a muffler outer shell, and exhaust gas flowing from the inlet opening end is supplied to a muffler outer shell. An exhaust muffler for a vehicle having a tail pipe leading to the outside and a finisher coupled to the tail pipe and having a larger diameter than the tail pipe whose outlet opening end is set outside the muffler shell, A connection portion with the finisher is set in a muffler outer shell.

According to a second aspect of the present invention, in the vehicle exhaust silencer according to the first aspect, the tail pipe has an outlet opening end having an outlet end plate, a baffle plate, and a shell as a chamber wall. It is a pipe set indoors.

According to a third aspect of the present invention, in the exhaust muffler for a vehicle according to the first aspect, the tail pipe has an outlet opening end formed by two baffle plates and a shell in the muffler. It is a pipe set in a sound deadening room.

According to a fourth aspect of the present invention, in the vehicle exhaust silencer according to the first aspect, the second aspect or the third aspect, the connecting portion between the tail pipe and the finisher includes a tail pipe and a finisher. At least one has a diameter changing portion that is gradually increased or decreased in diameter.

According to a fifth aspect of the present invention, in the exhaust muffler for a vehicle according to the fourth aspect, the diameter changing portion is formed by crimping a portion connected to a tail pipe of a finisher.

[0011]

According to the first aspect of the present invention, an inlet opening end is set in the muffler outer shell, and a tail pipe for guiding exhaust gas flowing from the inlet opening end to the outside of the muffler outer shell. And a connection portion with a finisher having a larger diameter than the tail pipe whose outlet opening end is set outside the muffler outer shell is set in the muffler outer shell.

As a result, the joint between the tail pipe and the finisher, which impairs the appearance, is not exposed to the outside. In addition, the finisher can be set even in a muffler having a tail pipe in which the dimension between the outlet opening end and the joint between the muffler outer shell is extremely short. Furthermore, by increasing the length of the finisher as compared to the conventional technology, it is possible to increase the dimension between the joint between the finisher and the tail pipe and the outlet opening end. Even if turbulence occurs in the exhaust gas due to the difference in diameter of the exhaust gas, it is rectified when flowing through the finisher.

Therefore, the finisher can be set without impairing the appearance and without being restricted by the layout, and the generation of air flow noise can be reduced even if turbulence occurs in the exhaust gas.

According to the second aspect of the present invention, the outlet opening end of the tail pipe is set in the sound deadening chamber having the outlet side end plate, the baffle plate, and the shell as a chamber wall.

That is, since turbulence occurs in the exhaust gas due to the difference in diameter between the finisher and the tail pipe, the outlet opening end of the tail pipe where air flow noise and abnormal noise are likely to be generated can be set inside the muffler body. The sound generated at the end of the tail pipe at the outlet opening can be shielded by the muffler shell.

Thus, when the difference between the diameter of the tail pipe and the diameter of the finisher is large and airflow noise or abnormal noise is generated at the end of the tail pipe at the opening end, the diameter of the tail pipe is conventionally increased while deteriorating the muffled sound. Although it was necessary to take measures against abnormal noise, the abnormal noise can be shielded by the shell, so that the finisher can be set without deteriorating the muffled sound.

By the way, the larger the diameter of the tail pipe is, the smaller the difference in inner diameter from the finisher is, which is advantageous for the generation of airflow noise. Off relationship.

According to the third aspect of the present invention, the outlet opening end of the tail pipe is set in a silencer room having two baffle plates and a shell in the silencer as a room wall.

Therefore, in addition to obtaining the same operation and effect as the invention according to the second aspect, the length from the open end of the finisher to the joint with the tail pipe is larger than that of the second aspect. Can be set longer, so that airflow noise and abnormal noise can be further reduced.

According to a fourth aspect of the present invention, a connection having a diameter changing portion in which at least one of the tail pipe and the finisher gradually increases or decreases in diameter is provided at the connection between the tail pipe and the finisher. Is done.

That is, there is a large diameter difference between the tail pipe and the finisher, and when the exhaust gas enters the finisher from the outlet opening end of the tail pipe, when the exhaust pipe has a stepped pipe shape, a turbulent flow occurs in the exhaust gas. This causes airflow noise and abnormal noise.

On the other hand, when the exhaust gas enters the finisher from the outlet opening end of the tail pipe, the diameter of the pipe is gradually increased by the diameter changing section so that the cross-sectional area of the pipe is gradually increased. The turbulence of the exhaust gas that causes the exhaust gas can be suppressed.

In the invention according to claim 5, the diameter changing portion is a finisher in which a portion to be connected to the tail pipe is crimped.

Thus, the manufacturing cost can be reduced by simple crimping.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an exhaust muffler for a vehicle according to the present invention.
First Embodiment Corresponding to Claims 4 and 5, and Claim 3
A description will be given based on a second embodiment corresponding to the fourth embodiment, a third embodiment corresponding to the fourth embodiment, and a fourth embodiment corresponding to the fourth embodiment.

(First Embodiment) First, the configuration will be described. FIG. 1 is a sectional view showing a vehicle exhaust silencer M1 of a first embodiment applied as a main muffler of an automobile exhaust system,
In the figure, 1 is an exhaust input tube, 2 is a shell, 3 is an inlet end plate, 4 is an outlet end plate, 5 is a first baffle plate, 6 is a second baffle plate, and 7 is a first baffle plate.
An expansion room, 8 is a second expansion room, 9 is a resonance room, 10 is an inlet pipe, 11 is a tail pipe, 12 is a finisher, and A1 is a joint.

The shell 2, the inlet-side end plate 3, and the outlet-side end plate 4 constitute an outer shell of the vehicle exhaust silencer M1.
The first expansion chamber 7 and the second baffle plate 6
It is defined by an extension room 8 and a resonance room 9. The first
The baffle plate 5 has a first expansion chamber 7 and a second expansion chamber 8.
A communication hole 5a that communicates with the opening is formed.

The inlet pipe 10 has an inlet-side open end 10a connected to an exhaust input tube 1 for inputting exhaust gas from an engine (not shown), and an outlet-side open end 10b in a muffler set in the resonance chamber 9. The inlet side end plate 3, the first baffle plate 5, and the second baffle plate 6 are fixed by pipes at three points. The inlet pipe 10 has a first small hole 10 c for sending a part of the exhaust gas to the first expansion chamber 7, and a second expansion chamber 8.
And a second small hole 10d for sending a part of the exhaust gas to the second hole.

The tail pipe 11 has an inlet opening end 11.
a is set in the first expansion chamber 7 in the muffler outer shell, the outlet opening end 11b is set in the resonance chamber 9 in the muffler outer shell, and the pipe inside the muffler guides the exhaust gas to the outside of the muffler outer shell. The first baffle plate 5 and the second baffle plate 6 are fixed by two-point support. And this tail pipe 11
A small hole 11c for taking in exhaust gas from the first expansion chamber 7 is formed in the inlet opening end 11a.

The finisher 12 has an inlet opening end 1.
The 2a portion is connected to the outlet opening end 11b portion of the tail pipe 11, the outlet opening end 12b is set outside the muffler outer shell, and the pipe diameter is larger than the tail pipe 11,
The connecting portion A1 and the outlet end plate 4 are fixed by two-point support. The exit opening end 12b of the finisher 12 has an oblique cut shape in consideration of the appearance.

The tail pipe 11 and the finisher 1
2 is set in a resonance chamber 9 inside the muffler outer shell and having the outlet side end plate 4, the second baffle plate 6, and the shell 2 as a chamber wall.

FIG. 2 is a perspective view showing a joint A1 between the tail pipe 11 and the finisher 12.
Reference numeral 1 denotes a crimping process at a joint portion of the finisher 12 and spot welding with the tail pipe 11 (welded portion 13).
It is fixed by. In FIG. 2, reference numeral 14 denotes a crushed ridge portion formed by crimping, 15 denotes a cylindrical surface portion formed between adjacent crushed ridge portions 14 and 14 by crimping, and 16 denotes a cylindrical surface portion and a finisher 12 formed by crimping. It is a step surface portion formed between the outer cylinder surface.

Next, the operation will be described.

[Action by setting inside of silencer outer shell of joint]
First, an inlet opening end 11a is set in a muffler outer shell, and a tail pipe 11 for leading exhaust gas to the atmosphere, and an outlet opening end 12b is a finisher 12 having a larger diameter than a tail pipe set outside the muffler outer shell. Is set in the muffler outer shell.

Therefore, unlike the prior art, the joint A1 between the tail pipe 11 and the finisher 12, which impairs the appearance, is not exposed to the outside.
2 settings can be made.

Further, the tail pipe 1 having an extremely short dimension between the outlet opening end 12b and the connecting portion of the end plate 4
Even with the muffler having 1, the finisher 12 can be set. By the way, there are many layout problems as causes of the tail pipe 11 becoming short, for example, when it is desired to shorten the overhang on the rear side of the vehicle, or when the main muffler is disposed at the rear end of the vehicle. is there.

Further, by setting the inlet opening end 12a of the finisher 12 inside the muffler outer shell, the length of the finisher 12 can be made longer as compared with the prior art in which the finisher inlet opening end is outside the muffler outer shell. Since it is possible to increase the length, even if turbulence occurs in the exhaust gas due to the difference between the diameter of the finisher 12 and the diameter of the tail pipe 11 at the outlet opening end 11b of the tail pipe 11, this causes a long axial length. The flow is rectified when flowing through the finisher 12.

[Connection between Tail Pipe and Finisher] The connection between the tail pipe 11 and the finisher 12 is achieved by the tail pipe 11 having no connection portion processed.
And finisher 1 with crimped joints
2 are fixed by spot welding.

That is, the finisher 12 is partially crushed at several locations on the outer periphery at equal intervals (four in the first embodiment) to form a crushing ridge 14 in the pipe axial direction. A crimping process is performed so that the inner diameter of the joint portion, which is the inner surface diameter, is slightly larger than the outer diameter of the tail pipe 11.

The tail pipe 11 is inserted into the crimped joint of the finisher 12, and the tail pipe 11 and the cylindrical surface portion 15 of the finisher 12 are spot-welded to each other by spot welding. Are combined.

The crimping employed here has an advantage that it is simpler than the drawing described later. Although crimping is difficult in appearance, the joint A1 is set in the silencer outer shell as described above, so that there is no problem in appearance.

[Silence Effect] The exhaust gas guided from the engine to the exhaust input tube 1 is introduced into the inlet pipe 10 of the vehicle exhaust silencer M1, and as shown by the arrow in FIG. → 1st expansion room 7 → entrance open end 11
a or the second small hole 10d → the second expansion chamber 8 → the communication hole 5
a → the first expansion chamber 7 → the inlet opening end 11a, the expansion action by the two expansion chambers 7 and 8 (the pressure is reduced by expanding the exhaust gas, and the sound is attenuated by the interference of the reflected waves by the chamber walls). Action) attenuates the exhaust noise.
Further, a resonance effect (operation of silencing a sound in a specific resonance frequency range) by the resonance chamber 9 is added, and the sound is silenced in combination with the expansion effect. The exhaust gas flowing from the inlet opening end 11a of the tail pipe 11 is supplied to the tail pipe 11 →
The connection portion A1 is emitted to the atmosphere through the finisher 12.

Here, in the first embodiment, the tail pipe 1
1 is an outlet opening end 11b of the resonance chamber 9 having the outlet end plate 4, the second baffle plate 6, and the shell 2 as chamber walls.
Is set within.

That is, since the outlet opening end 11b of the tail pipe 11 where airflow noise and abnormal noise are likely to be generated can be set inside the muffler outer shell, the outlet opening end 11b of the tail pipe 11 can be set.
The sound generated at b is transmitted to the finisher 12 → the exit side end plate 4 → the shell 2 and the vehicle silencer M
Sound can be shielded by the first shell 2.

As a result, when the difference between the diameter of the tail pipe and the diameter of the finisher is large and an airflow noise or an abnormal noise is generated at the outlet opening end 11b of the tail pipe 11, the diameter of the tail pipe is reduced while the booming sound is deteriorated. However, since the sound can be shielded by the shell 2, the finisher 12 can be set without deteriorating the muffled sound.

The larger diameter of the tail pipe 11 is advantageous for the generation of airflow noise because the inner diameter difference between the tail pipe 11 and the finisher 12 is smaller. However, the larger the diameter of the tail pipe 11, the more easily muffled sound is produced. No, there is a trade-off relationship.

Next, the effects will be described.

(1) The inlet opening end 11a is set inside the muffler outer shell, the tail pipe 11 for guiding exhaust gas to the outside of the muffler outer shell, and the outlet opening end 12b is set outside the muffler outer shell. Since the connecting portion A1 with the finisher 12 having a larger diameter than the tail pipe is set in the muffler outer shell, the finisher 12 can be set without impairing the appearance and without being restricted by the layout. Even if turbulence occurs in the exhaust gas, generation of airflow noise can be reduced.

(2) Since the tail pipe 11 in which the joint is not subjected to any processing and the finisher 12 in which the joint is crimped are fixed by spot welding, the crimping is simpler than drawing. ,
The manufacturing cost can be reduced.

(3) Outlet opening end 11b of tail pipe 11
With the outlet end plate 4 and the second baffle plate 6
And the shell 2 are set in the resonance chamber 9 as a chamber wall, so that the airflow noise and the unusual noise generated at the outlet opening end 11b of the tail pipe 11 can be blocked by the shell 2, and the muffled sound is deteriorated. Without setting, the finisher 12 can be set.

(Second Embodiment) As shown in FIG. 3, a vehicle silencer M2 according to a second embodiment is configured such that an outlet opening end 11b of a tail pipe 11 is connected to two baffle plates 5 in an outer shell of the silencer. This is an example in which the interior is set in a second expansion room 8 having a room wall 6 and a shell 2. Therefore, the joint A2 is also set in the second expansion chamber 8. Since the other configuration is the same as that of the first embodiment (FIGS. 1 and 2), the same reference numerals are given to the drawings and the description is omitted. Also, the operation is the same as that of the first embodiment, and the description is omitted.

Next, the effects will be described.

In the vehicle exhaust silencer M2 of the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

(4) Outlet opening end 11b of tail pipe 11
Is set in the second expansion chamber 8 having the two baffle plates 5 and 6 in the outer shell of the silencer and the shell 2 as a chamber wall, so that the connection portion between the outlet opening end 12b of the finisher 12 and the tail pipe 11 is formed. Since the length up to A2 can be set longer than in the first embodiment, when turbulence occurs in the exhaust gas, the air flow noise can be further reduced by the rectifying action of the long finisher 12 than in the first embodiment. it can.

(Third Embodiment) In the first and second embodiments, the joints A1 and A2 are formed by crimping, whereas in the third embodiment, the joints A3 and A4 are formed by drawing.

That is, as shown in FIG. 4, the connecting portion A3 between the tail pipe 11 and the finisher 12 reduces the diameter of the connecting area of the finisher 12 from the outer diameter of the finisher 12 by drawing. Part 17
And the cylindrical portion 18 having an inner diameter slightly larger than the outer diameter of the tail pipe 11, and the tail pipe 11 having nothing formed and the cylindrical portion 1 of the finisher 12.
8 is a connecting portion fixed by spot welding (welded portion 19).

Further, as shown in FIG.
1 and the finisher 12 are connected to the tail pipe 11 by drawing the tail pipe 11 in the connection area.
1 and a cylindrical portion 21 having an inner diameter slightly larger than the outer diameter of the finisher 12, and the cylindrical portion 21 of the tail pipe 11 is molded. The unfinished finisher 12 is a connection portion fixed by spot welding (welded portion 22).

The other structure is the same as that of the first embodiment (FIG. 1) or the second embodiment (FIG. 3), so that illustration and description are omitted. Also, the operation is the same as that of the first embodiment, and the description is omitted.

Next, the effects will be described.

In the third embodiment, the first embodiment
The following effects can be obtained in addition to the effects (1) and (3).

(5) Tail pipe 11 and finisher 1
The connecting portions A3 and A4 of the tail pipe 11 are formed by gradually expanding or reducing the diameter of one of the connecting regions of the tail pipe 11 and the finisher 12 by drawing, and fixed by spot welding. End 11b
When exhaust gas enters the finisher 12 from above, turbulence of exhaust gas which causes air flow noise can be suppressed by the smooth shape of the pipe shape gradually increasing the pipe cross-sectional area by drawing. it can.

(Other Embodiments) The exhaust muffler for a vehicle according to the present invention has been described based on the first to third embodiments, but the specific configuration is limited to these embodiments. However, design changes and additions are permitted without departing from the gist of the invention according to each claim of the claims.

For example, in the embodiment, an example of crimping + spot welding or drawing + spot welding has been described as an example of a connection structure between a tail pipe and a finisher. Alternatively, a joint structure with a joint member interposed may be used.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a vehicle exhaust silencer according to a first embodiment.

FIG. 2 is a perspective view showing a joint between a tail pipe and a finisher in the vehicle exhaust silencer of the first embodiment.

FIG. 3 is a sectional view showing a vehicle exhaust silencer according to a second embodiment.

FIG. 4 is a perspective view showing a connection portion between a tail pipe and a finisher in a vehicle exhaust silencer according to a third embodiment.

FIG. 5 is a perspective view showing a joint between a tail pipe and a finisher in the vehicle exhaust silencer of the third embodiment.

FIG. 6 is a view showing a conventional vehicle exhaust silencer.

[Explanation of symbols]

 M1 Exhaust silencer for vehicle 1 Exhaust input tube 2 Shell 3 Inlet end plate 4 Outlet end plate 5 First baffle plate 6 Second baffle plate 7 First expansion room 8 Second expansion room 9 Resonance room 10 Inlet pipe 10a Inlet Open end 10b Outlet open end 11 Tail pipe 11a Inlet open end 11b Outlet open end 12 Finisher 12a Inlet open end 12b Outlet open end A1 Joint

Claims (5)

[Claims] 1. An inlet opening end is set in a muffler shell,
A tail pipe that guides exhaust gas flowing from the inlet opening end to the outside of the muffler outer shell, and a finisher coupled to the tail pipe, the outlet opening end of which is larger in diameter than the tail pipe set outside the muffler outer shell, A vehicle exhaust silencer having: a joint between the tail pipe and the finisher,
An exhaust muffler for a vehicle, wherein the muffler is set in a muffler outer shell. 2. The exhaust muffler for a vehicle according to claim 1, wherein the tail pipe is a pipe whose outlet opening end is set in a sound deadening chamber having an outlet side end plate, a baffle plate, and a shell as a chamber wall. An exhaust muffler for a vehicle, comprising: 3. The exhaust muffler for a vehicle according to claim 1, wherein the tail pipe has an outlet opening end provided in the muffler.
An exhaust silencer for a vehicle, comprising: a pipe set in a silencer room having two baffle plates and a shell as a room wall. 4. The method according to claim 1, 2 or 3.
The exhaust muffler for a vehicle according to any one of claims 1 to 3, wherein a coupling portion between the tail pipe and the finisher has a diameter changing portion in which at least one of the tail pipe and the finisher gradually increases or decreases in diameter. Exhaust silencer for vehicles. 5. The exhaust muffler for a vehicle according to claim 4, wherein the diameter changing portion is formed by crimping a portion of the finisher connected to a tail pipe.