JP2006307719A - Muffler for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler for a vehicle capable of preventing a radiation sound of a shell by the pulsing pressure of exhaust gas exhausted from a punching hole of an inlet pipe. <P>SOLUTION: The inlet pipe 8 for making the exhaust gas flow in and an outlet pipe 9 for exhausting the exhaust gas, are arranged in the muffler surrounded by two end plates 3 and 4 and the shell 2, and the punching hole 12 is formed in the inlet pipe 8. In the muffler 1 for the vehicle for arranging the inlet pipe 8 and the shell 2 in close vicinity, the punching hole 12 is formed in a part except for a part in the close vicinity of the shell 2 side on the outer periphery of the inlet pipe 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a muffler for a vehicle, and more particularly to a muffler for a vehicle in which an exhaust pipe having a punching hole is disposed in the state of being close to an inner wall of a shell.

Conventionally, a muffler for a vehicle is provided with an inlet pipe for flowing exhaust gas and an outlet pipe for discharging exhaust gas in a muffler surrounded by two end plates and a shell.
In addition, by providing a punching hole in the inlet pipe and communicating with the expansion chamber in the silencer, the energy of the exhaust gas in the inlet pipe that flows into the silencer first, which is the first high temperature, high pressure, and high speed, is expanded and reduced. A technique for achieving a silencing effect is known (see Patent Document 1).

Due to the narrowing of the vehicle floor space accompanying the recent expansion of the vehicle interior space, the vehicle silencer disposed under the vehicle floor has been made compact, and in particular, the thickness direction has become thinner. Therefore, the inlet pipe is often disposed in the state of being close to the inner wall of the shell.
JP-A-5-187218

  However, in the conventional vehicle silencer, as shown in FIG. 6, since the punching holes 012 are arranged at equal intervals on the entire circumference of the inlet pipe 08, the punching holes 012 are discharged. The exhaust gas directly collides with the shell 02, and as a result, there is a problem in that a radiated sound is generated by vibration of the shell 02 caused by the pulsation pressure of the exhaust gas.

  Even when punching holes are provided in the intermediate pipe, the exhaust gas directly collides with the shell, but the energy of the exhaust gas is already attenuated when introduced into the expansion chamber from the inlet pipe. The above problems are less likely to occur.

  The present invention has been made to solve the above-described problems, and an object of the present invention is for a vehicle that can prevent a radiated sound due to vibration of a shell due to pulsation pressure of exhaust gas discharged from a punching hole of an inlet pipe. It is to provide a silencer.

  In the invention according to claim 1 of the present invention, an silencer surrounded by two end plates and a shell is provided with an inlet pipe for flowing exhaust gas and an outlet pipe for discharging exhaust gas, In the vehicle silencer in which the punching hole is formed in the inlet pipe and the inlet pipe and the shell are arranged close to each other, the punching hole is formed in a portion excluding the portion close to the shell side on the outer periphery of the inlet pipe. It is characterized by that.

  In the first aspect of the present invention, an inlet pipe for allowing exhaust gas to flow into a silencer surrounded by two end plates and a shell, and an outlet pipe for discharging exhaust gas In the vehicle silencer in which the punching hole is formed in the inlet pipe and the inlet pipe and the shell are arranged close to each other, the punching hole is a part excluding the part close to the shell side on the outer periphery of the inlet pipe Therefore, the exhaust sound does not directly collide with the shell, and the radiated sound of the shell due to the pulsation pressure of the exhaust gas discharged from the punching hole of the inlet pipe can be prevented.

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

Example 1 will be described below.
1 is a side sectional view showing a muffler for a vehicle according to a first embodiment of the present invention, FIG. 2 is a perspective view showing the muffler for a vehicle according to the first embodiment, and FIG. 3 is an end view taken along line S3-S3 in FIG. 4 is an end view taken along the line S4-S4 in FIG. 1, and FIG. 5 is a diagram showing the results of a noise measurement experiment of the conventional vehicle silencer and the vehicle silencer of the first embodiment.

First, the overall configuration will be described.
As shown in FIGS. 1 to 3, the vehicle silencer 1 of the first embodiment includes a shell 2, two end plates 3 and 4, three baffle plates 5, 6 and 7, and an inlet pipe 8. The outlet pipe 9 is provided, and is formed in a flat tubular shape in which the lateral length W2 is extremely short with respect to the longitudinal length W1.

The shell 2 is provided in a state in which a metal plate material is wound around the outer peripheries of the end plates 3 and 4 and the baffle plates 5, 6 and 7.
The silencer surrounded by the shell 2 and the end plates 3 and 4 is provided with metal plate baffle plates 5, 6 and 7, and each of the baffle plates 5, 6 and 7 has a plurality of openings. Part 10 is formed.
Accordingly, four chambers R1, R2, R3, R4 communicating with each other through the openings 10 of the baffle plates 5, 6, 7 are formed in the silencer.

  The inlet pipe 8 is for allowing exhaust gas to flow into the silencer, and is provided in a state of penetrating from the side of the shell 2 through the substantially cylindrical adapter 20 to the chamber R3 in the silencer. Yes.

Further, the tip of the inlet pipe 8 is in a state of being blocked by the cap member 11.
In the first embodiment, the distal end side of the inlet pipe 8 is closed with the cap member 11, but a small-diameter small hole may be provided in the cap member 11.

Furthermore, as shown in FIG. 4, a plurality of punching holes 12 opened only on the side of the outer periphery of the inlet pipe 8 are formed.
Therefore, the punching hole 12 is formed at a portion on the outer periphery of the inlet pipe 8 excluding a portion close to the shell 2 side.
In addition, it is preferable to arrange | position the formation position of the punching hole 12 of the present Example 1 toward the flat tubular arc part of the shell 1. This is because the arc portion is relatively rigid and does not vibrate.
For example, if the angle at which the direction of the punching hole 12 intersects the longitudinal wall of the shell is 45 degrees or less, the component force that vibrates the wall surface is reduced, which is preferable.

  The outlet pipe 9 discharges the exhaust gas in the silencer and is provided in a state of passing through the end plate 3 and the baffle plates 5, 6, and 7 and communicating with the chamber R4.

Next, the operation will be described.
In the vehicle silencer 1 configured as described above, the base end side of the inlet pipe 8 is connected to an exhaust pipe (not shown) on the engine side, and the base end side of the outlet pipe 9 is connected to a tail pipe (not shown). It is mounted on the vehicle in the state where it is done.

The exhaust gas flowing into the inlet pipe 8 from the exhaust pipe on the engine side (shown by the wavy arrow in FIG. 1) expands when flowing into the chamber R3 in the silencer through the punching hole 12 of the inlet pipe 8. Is done.
Next, the sound is silenced while being subjected to expansion and contraction while flowing between the chambers R1, R2, R3, and R4 through the openings 10 of the baffle plates 5, 6, and 7, and then the tail pipe is removed from the outlet pipe 9. It is discharged to the outside through.

Here, in the conventional invention, since the punching holes are arranged at equal intervals all around the outer periphery of the inlet pipe, the exhaust gas discharged from the punching holes directly collides with the shell. There was a problem that radiated sound was generated by vibration of the shell caused by the pulsation pressure of the exhaust gas.
In particular, when it directly collides with a flat portion having a relatively low rigidity, it is easy to vibrate and radiated sound is likely to be generated.

  Even when punching holes are provided in the intermediate pipe, the exhaust gas directly collides with the shell, but the energy of the exhaust gas has already been introduced into the expansion chamber from the inlet pipe and has been attenuated. The above problems are less likely to occur than the inlet pipe that flows into the pipe.

  However, in the muffler for a vehicle according to the first embodiment, the punching hole 12 is formed in a portion excluding a portion close to the shell 2 side on the outer periphery of the inlet pipe 8, and as shown in FIG. 4. There is no possibility that the exhaust gas discharged from the punching hole 12 of the inlet pipe 8 directly collides with the shell 2, and it is possible to prevent the radiated sound of the shell 2 from being generated.

  Further, when the front end of the inlet pipe is fully opened, most of the exhaust gas is exhausted from the front end and directly collides with the shell while being distributed over the entire circumference. Since the tip is closed by the cap member 11, all of the exhaust gas can be discharged from the punching hole 12 to have directionality, and the exhaust gas can be reliably prevented from directly colliding with the shell 2.

Here, the result of having conducted the noise measurement experiment of the conventional vehicle silencer and the vehicle silencer of the first embodiment is shown in FIG.
As shown in FIG. 5, in the vehicle silencer 1 according to the first embodiment, the radiated sound caused by the vibration of the shell is eliminated, so that the engine speed is substantially the entire range as compared with the conventional vehicle silencer 1. It was proved that noise can be reduced.

Next, the effect will be described.
As described above, in the vehicle silencer according to the first embodiment, the inlet pipe for allowing the exhaust gas to flow into the silencer surrounded by the two end plates 3 and 4 and the shell 2. 8 and an outlet pipe 9 for discharging exhaust gas, a punching hole 12 is formed in the inlet pipe 8, and a punching hole is provided in the vehicle silencer 1 in which the inlet pipe 8 and the shell 2 are disposed close to each other. Since 12 is formed on the outer periphery of the inlet pipe 8 except for the portion close to the shell 2 side, it is possible to prevent the radiated sound generated from the shell 2 due to the pulsating pressure of the exhaust gas discharged from the punching hole 12 of the inlet pipe 8. .

Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within the scope not departing from the gist of the present invention are included in the present invention.
For example, the size, shape, and number of punched holes 12 can be set as appropriate.
In the first embodiment, the case of the flat tubular vehicle silencer 1 has been described. However, a cylindrical or substantially triangular prism may be used. That is, the present invention can be applied to all vehicle silencers 1 in which the inlet pipe 8 and the shell 2 are arranged close to each other.
The same applies when the inlet pipe passes through the end plate and opens into the silencer.
Moreover, in Example 1, although the internal structure which consists of two end plates and three baffle plates was shown, it is applicable also to a silencer of various structures.
In addition, when the inlet pipe is biased to one side in the short direction of the silencer, it is possible to not provide the punching hole only on the outer periphery in the direction closer to the shell wall.

It is a sectional side view which shows the silencer for vehicles of Example 1 of this invention. It is a perspective view which shows the silencer for vehicles of the present Example 1. It is an end view in the S3-S3 line of FIG. It is an end elevation in S4-S4 line of FIG. It is a figure which shows the result of having performed the radiation sound measurement experiment of the conventional vehicle silencer and the vehicle silencer of the present Example 1. FIG. It is a figure explaining the conventional silencer for vehicles.

Explanation of symbols

R1, R2, R3, R4 Chamber 1 Vehicle silencer 2 Shell 3, 4 End plate 5, 6, 7 Baffle plate 8 Inlet pipe 9 Outlet pipe 10 Opening 11 Cap member 12 Punching hole 20 Adapter

Claims (1)

In the silencer surrounded by the two end plates and the shell, an inlet pipe for injecting exhaust gas and an outlet pipe for exhausting the exhaust gas are provided.
In the muffler for a vehicle in which a punching hole is formed in the inlet pipe, and the inlet pipe and the shell are arranged close to each other,
A muffler for a vehicle, wherein the punching hole is formed in a portion excluding a portion close to the shell side on the outer periphery of the inlet pipe.

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