JP2008031851A - Muffler for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler for a vehicle, reducing radiated sound, by enhancement of surface rigidity of end plates without increase in thickness of the end plates. <P>SOLUTION: In the muffler A for a vehicle, both end parts of a tubular shell 1 of a muffler body 4 are fixed to outer peripheral parts of the corresponding end plates 2, 3 by lock seam parts 10. Each contact groove 9 to be abutted with a tool 11 in forming the lock seam parts 10 is formed on the outer peripheral part of each of the end plates 2, 3, while being recessed inward of the muffler body 4. A bead 9b extending in a radial direction of the muffler body 4 is formed in the contact groove 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle muffler.

2. Description of the Related Art Conventionally, a vehicle muffler technology in which both end portions of a cylindrical shell in a muffler main body and outer peripheral portions of corresponding end plates are fixed by lock seam portions is known (see Patent Documents 1 and 2).
JP 2005-233167 A JP 2005-264832 A

However, the conventional vehicle muffler has a problem in that radiated sound is easily generated due to the low surface rigidity of the end plate.
Therefore, the end plate is formed into a dish shape that swells to the outside of the muffler body, or the plate thickness is increased to increase the surface rigidity. However, increasing the plate thickness increases the weight, which is not preferable. .

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a vehicle capable of reducing the radiated sound by increasing the surface rigidity of the end plate without increasing the plate thickness. Is to provide a muffler.

  According to the first aspect of the present invention, both end portions of the cylindrical shell in the muffler main body and the outer peripheral portions of the corresponding end plates are fixed by lock seam portions, and the lock seam is fixed to the outer peripheral portion of the end plate. In a vehicle muffler formed with a contact groove for abutting a jig when forming a portion recessed inside the muffler body, a bead extending in the radial direction of the muffler body is formed in the contact groove It is characterized by that.

  In the invention according to claim 1 of the present invention, both end portions of the cylindrical shell in the muffler body and the outer peripheral portion of the corresponding end plate are fixed by the lock seam portion, and the outer peripheral portion of the end plate is In a vehicle muffler formed with a contact groove for contacting a jig for forming the lock seam portion being recessed toward the inside of the muffler body, a bead extending in the radial direction of the muffler body in the contact groove Therefore, it is possible to increase the surface rigidity of the end plate without increasing the plate thickness and reduce the radiated sound.

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

Example 1 will be described below.
1 is a cross-sectional view illustrating the inside of a vehicle muffler according to a first embodiment of the present invention, FIG. 2 is an enlarged view of the vicinity of a lock seam portion, FIG. 3 is a perspective view of an end plate according to the first embodiment, and FIG. It is a figure explaining fitting of a plate and a jig.

First, the overall configuration will be described.
As shown in FIG. 1, in the vehicle muffler A of the first embodiment, the muffler body 4 is composed of a cylindrical shell 1 and circular, substantially dish-shaped end plates 2 and 3 that close both ends of the shell 1. It is configured.

The inside of the muffler body 4 is partitioned into two chambers R1 and R2 by a circular metal plate-like baffle plate 5, and the chamber R1 is filled with a sound absorbing material 6 made of glass wool. In addition, the material of the sound absorbing material 6, a filling density, etc. can be set suitably.
Further, the baffle plate 5 and the shell 1 are fixed at a plurality of locations on the circumference of both by spot welding X1.

Further, a metal exhaust pipe 7 is provided in a state of penetrating both the end plates 2 and 3 and the baffle plate 5, and through holes 7a and 7b communicated with the two chambers R1 and R2 on the outer periphery of the exhaust pipe 7, respectively. A plurality of are formed.
The exhaust pipe 7 is fixed over the entire circumference of both of them by the end plates 2 and 3 and the weld X2, and is also fixed by the baffle plate 5 and the weld X3 over the entire circumference of both of them.

Hereinafter, the fixing structure of the shell 1 and the end plates 2 and 3 will be described.
As shown in FIGS. 2 and 3, the end plate 2 (3) is formed in a circular substantially dish shape that swells outside the muffler body 4 toward the through hole 8 through which the exhaust pipe 7 passes, and its outer periphery. A contact groove 9 that is recessed toward the inside of the muffler body 4 is formed in the part.

  In addition, beads 9 b that are recessed toward the inside of the muffler body 4 are extended in the radial direction of the muffler body 4 at four locations on the circumference of the flat portion 9 a of the contact groove 9.

  As a result, the rigidity around the contact groove 9 can be increased, and the surface rigidity of the end plate 2 (3) can be improved without increasing the thickness of the end plate 2 (3), thereby increasing the vibration eigenvalue. Yes.

In addition, the formation position of the bead 9b can be set as appropriate.
As a result of analyzing the vibration eigenvalue of the end plate 2 (3), if the depth from the lock seam portion 10 to the bead 9b shown in FIGS. 2 and 3 is D (around 10 mm), the height of the bead 9b is H = D × 1/3 (around 3 mm) and bead width W = H × 2 (around 6 mm) were suitable.

The shell 1 is formed by forming a metal plate into a cylindrical shape and joining both edges thereof by welding outside the figure, and both ends thereof and the outer peripheral edge portions of the end plates 2 and 3 are lock seams. Each is fixed by a lock seam portion 10 formed by machining.
Note that the shell 1 may be formed by winding multiple metal plate materials.

Next, the operation will be described.
When manufacturing the vehicle muffler A configured as described above, first, the baffle plate 5 and the exhaust pipe 7 are fixed by welding X3, and then both of them are arranged inside the shell 1 to arrange the baffle plate 5 and the shell. 1 is fixed by spot welding X1.

  Next, at the both end portions of the shell 1, the through holes 8 of the corresponding end plates 2 and 3 are passed through the exhaust pipe 7, and these three members are fixed by welding X2.

  Finally, the outer peripheral portions of the end plates 2 and 3 respectively corresponding to both end portions of the shell 1 are subjected to lock seam processing to form a lock seam portion 10 to fix these three members.

At this time, as shown in FIG. 4, the lock seam portion 10 is formed between the jig 11 that is in contact with the contact groove 9 and the processing die of the lock seam processing machine that is not shown.
The bead 9b is fitted with a convex portion 11a protruding from the jig 11, so that relative rotation between the jig 11 and the end plates 2 and 3 during lock seam processing can be suppressed.

  Therefore, the bead 9b can also be used as a means for positioning and fixing the jig 11.

  The vehicle muffler A configured as described above has an exhaust pipe 7 on the exhaust gas upstream side of the exhaust pipe 7 connected to the exhaust pipe 7 on the engine side (not shown), while a main exhaust (not shown) on the downstream end of the exhaust gas. The exhaust pipe 7 on the muffler side is connected.

  Then, as shown in FIG. 1, the sound energy of the exhaust gas (illustrated by broken line arrows) flowing through the exhaust pipe 7 from the engine side is dispersed and absorbed by the sound absorbing material 6 in the chamber R1 through the through holes 7a. The exhaust noise can be reduced.

  Further, the sound energy of the exhaust gas in the exhaust pipe 7 flows into the chamber R2 through the through hole 7b and generates a predetermined resonance frequency so that the exhaust noise can be reduced.

Here, in the conventional invention, the conventional vehicle muffler has a problem in that radiated sound is easily generated due to the low surface rigidity of the end plate.
Therefore, as a result of analyzing the surface rigidity of the end plate, it has been found that the rigidity of the peripheral portion of the contact groove is low, which causes generation of radiated sound.

  On the other hand, in the vehicle muffler A of the first embodiment, as described above, the beads 9b that are recessed toward the inside of the muffler main body 4 are formed at four locations on the circumference of the flat portion 9a of the contact groove 9, so that the end Radiation noise can be reduced by increasing the surface rigidity (vibration eigenvalue) of the plates 2 and 3.

  The increase in surface rigidity of the end plate 2 (3) obtained by the bead 9b depends on the position, shape, etc. of the bead 9b, but as a result of measuring the vibration eigenvalue, the thickness of the end plate 2 (3) is reduced to the conventional product. It was confirmed that the surface rigidity (vibration eigenvalue) was increased by 25% compared to the case.

Next, the effect will be described.
As described above, in the vehicle muffler A of the first embodiment, the lock seam portion 10 is provided on the outer peripheral portion of the end plates 2 and 3 corresponding to the both ends of the cylindrical shell 1 in the muffler body 4. The contact groove 9 for contacting the jig 11 when the lock seam portion 10 is formed is formed on the outer periphery of the end plates 2 and 3 in a state where the contact groove 9 is recessed toward the inside of the muffler body 4. In the muffler A, since the bead 9b extending in the radial direction of the muffler body 4 is formed in the contact groove 9, the surface rigidity of the end plates 2 and 3 is increased without increasing the plate thickness, thereby reducing radiated sound. Can do.

  Further, when the lock seam portion 10 is formed, the bead 9b and the jig 11 are fitted to prevent relative rotation between them, so that the bead 9b is positioned and fixed when the lock seam portion 10 is formed. It can also be used as a means.

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 a scope not departing from the gist of the present invention are included in the present invention.
For example, the cross-section of the muffler main body 4 is not limited to a circular shape, and an appropriate shape such as an elliptical shape, a quadrangular shape, a triangular shape, or a race track shape can be adopted.

  Moreover, the internal structure in the muffler main body 4 can be set as appropriate.

Furthermore, the shape, the number of formations, and the formation positions of the beads 9b can be appropriately set according to the cross section of the muffler body 4 and the shapes and thicknesses of the end plates 2 and 3.
Further, the bead 9b is formed by a groove recessed inside the end plates 2 and 3, but may be convex outward.

It is sectional drawing explaining the inside of the muffler for vehicles of Example 1 of this invention. It is an enlarged view near a rock seam part. It is a perspective view of the end plate of the present Example 1. It is a figure explaining fitting of an end plate and a jig.

Explanation of symbols

R1, R2 Chamber X1, X2, X3 Welding 1 Shell 2, 3 End plate 4 Muffler body 5 Baffle plate 6 Sound absorbing material 7 Exhaust pipe 7a, 7b Through hole 8 Through hole 9 Contact groove 9a Flat part 9b Bead 10 Lock seam part 11 Jig 11a Convex part

Claims (2)

Both end portions of the cylindrical shell in the muffler body and the outer peripheral portion of the corresponding end plate are fixed by the lock seam portion,
In the vehicle muffler formed on the outer periphery of the end plate in a state where a contact groove for contacting a jig when forming the lock seam portion is recessed toward the inside of the muffler body,
A muffler for a vehicle, wherein a bead extending in a radial direction of the muffler main body is formed in the contact groove. The vehicle muffler according to claim 1,
A muffler for a vehicle characterized in that when the lock seam portion is formed, a jig is fitted to a bead to prevent relative rotation between the two.

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