JPH0139852Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Technical field) The present invention relates to an exhaust pipe structure for an internal combustion engine.

(Prior art) The conventional exhaust pipe structure of an internal combustion engine, especially the structure of the finisher that covers the tail tube, is as follows (For example, Public Technical No. 83-2746, Public Technical Report Vo18-11 (149))
(Sho 58, March 22) Refer to the structure of the finisher described in the publication of the Institute of Invention and Innovation. ) There is one shown in Figure 7. In Fig. 7, 1 is the muffler body;
The muffler body 1 includes a cylindrical outer cylinder 2, an end plate 3 that closes both ends of the outer cylinder 2, and a muffler pipe 4 that is housed in the outer cylinder 2 and press-fitted into a burring part 3a of the end plate 3. have. One end of a tail tube 5 is press-fitted into the muffler pipe 4, and the other end of the tail tube 5 is open to the atmosphere. These muffler pipe 4, tail tube 5, and end plate 3 are integrally connected by welding (in the figure, reference symbol X indicates a welded portion (weld bead)). Further, approximately two-thirds of the rear portion of the tail tube 5 is covered with a cylindrical finisher 6 to improve the appearance of the so-called exhaust discharge end of the exhaust pipe. The finisher 6 is positioned by abutting its folded end 6a against the rear end 5a of the tail tube 5, and the fitting portion 6b having a narrowed inner diameter allows the finisher 6 to be positioned by abutting the rear end 5a of the tail tube 5.
The mating is fixed.

However, in the conventional exhaust pipe structure of an internal combustion engine, only a part of the tail tube 5 is covered with the finisher 6 (for example, to reduce costs), which prevents rust from forming. Since the welding part X, which is easy to weld, was configured to be exposed, there was a problem in that the rust in the welding part X was visually observed, and the effect of the finisher 6 was not necessarily fully exhibited.

(Purpose of the invention) Therefore, the present invention positions a part of the finisher against the muffler body or the rear end of the tail tube, and fits and fixes the finisher to the tail tube so as to cover the weld. The purpose is to improve appearance by preventing exposure of

(Structure of the invention) The exhaust pipe structure for an internal combustion engine according to the invention includes a tail tube whose one end is connected to the muffler body and whose other end is open to the atmosphere, and a finisher that is fitted and fixed to the tail tube and covers the tail tube. ing. The exhaust pipe structure positions the finisher so that a portion of the finisher abuts against the muffler body or the rear end of the tail tube, and is fitted and fixed to the tail tube so as to cover the connecting portion between the muffler body and the tail tube. It is intended to do so.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a diagram showing a first embodiment of the present invention,
Components that are the same as those in FIG. 7 shown as a conventional example are given the same reference numerals, and their explanations will be omitted.

In FIG. 1, a tail tube 11 is inserted into the muffler body 1, and the tail tube 1
1 is press-fitted into the burring portion 3a of the end plate 3. The tail tube 11 and the end plate 3 are welded and fixed at the burring portion 3a, with the weld bead indicated by X. The rear end portion of the tail tube 11 is enlarged in diameter, and a cylindrical finisher 12 is fitted into this enlarged diameter portion 11a. The finisher 12 is formed into a cylindrical shape having the same inner diameter as the enlarged diameter portion 11a, covers the weld bead X from the outside, and is positioned with its front end in contact with the end plate 3.

The following three conditions must be met when installing such a finisher 12.

() Must be able to perform positioning accurately.

() Completely cover weld bead X.

() It can be fixed to the tail tube 11 by a relatively easy manufacturing method of fitting.

In this first embodiment, the condition () is satisfied by the front end of the finisher 12 coming into contact with the end plate 3, and by increasing the inner diameter and length of the finisher than in the past, the condition () is satisfied. satisfies the conditions. Furthermore, by fitting the finisher 12 into the enlarged diameter portion 11a of the tail tube 11, the condition () is satisfied.
Therefore, even if rust occurs in the welded part X, visual inspection from the outside can be shielded,
Appearance can be improved.

FIG. 2 is a diagram showing a second embodiment of the present invention,
In describing the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted. This also applies to the third to fifth embodiments described later.

In the second embodiment, the rear end 2 of the tail tube 21
1a is not enlarged in diameter compared to the first embodiment, but is formed to have the same diameter. And tail tube 2
A finisher 22 having the same inner diameter as the tail tube 21 is fitted and fixed to the rear end portion 21a of the tail tube 1, and the front end side of the finisher 22 is enlarged in diameter to cover the weld bead X and also comes into contact with the end plate 3. are in contact with each other.

FIG. 3 is a diagram showing a third embodiment of the present invention.

In the third implementation, the rear end 31 of the tail tube 31
a is slightly enlarged in diameter compared to the second embodiment. A finisher 3 having a structure similar to that of the second embodiment is attached to the rear end portion 31a of the tail tube 31.
2 are fitted and fixed.

Therefore, in the second and third embodiments, the first
As in the embodiment, the condition () is satisfied by the front ends of the finishers 22, 32 coming into contact with the end plate 3, and by increasing the inner diameter of the front end of the finisher 12 to cover the weld bead X, the condition () is satisfied. The conditions are met. Further, the condition () is satisfied by fitting the finishers 22, 32 to the rear end portions 21a, 31a of the tail tubes 21, 31, respectively. Therefore, the first
Effects similar to those of the embodiment can be obtained.

FIG. 4 is a diagram showing a fourth embodiment of the present invention.

In the fourth embodiment, the tail tube 41 is constructed in the same manner as in the first embodiment. Further, a finisher 42 is provided at the rear end portion 41a of the tail tube 41.
are fitted and fixed, and the finisher 42 is formed with a recess Y that protrudes inward along its outer periphery. Further, the front end portion of the finisher 42 covers the weld bead X.

FIG. 5 is a diagram showing a fifth embodiment of the present invention.

In the embodiment shown in FIG. 5, the tail tube 51 is constructed in the same manner as in the third embodiment, and
As in the embodiment, a recess Y is formed and the front end of the finisher 52 is enlarged in diameter to cover the weld bead X.

FIG. 6 is a diagram showing a sixth embodiment of the present invention.

In the sixth embodiment, the tail tube 61 is constructed in the same manner as in the second embodiment, and the finisher 62 is constructed in the same manner as in the fifth embodiment.

Therefore, in the above fourth to sixth embodiments,
Rear end portion 41 of tail tube 41, 51, 61
a, 51, 61a come into contact with the recess Y, the condition () is satisfied, and the finishers 42, 52,
By increasing the inner diameter at the front end of 62 so as to cover the weld bead X, the conditions in parentheses are satisfied. Further, the condition () is satisfied by fitting the finishers 42, 52, 62 to the rear end portions of the tail tubes 41, 51, 61. Therefore, the same effects as in the first embodiment can be obtained.

In addition, in FIGS. 4, 5, and 6, the part of the finisher that butts against the rear end of the tail tube is a recess Y, but a folded end is provided as shown in 6a in FIG. Ideas can also be implemented.

(Effects) According to the present invention, the finisher can be fitted and fixed to the tail tube while covering the connecting portion between the muffler main body and the tail tube, and the appearance can be improved by preventing the connecting portion from being exposed. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a half sectional view of the main part showing the first embodiment of the present invention, Fig. 2 is a half sectional view of the main part showing the second embodiment of the invention, and Fig. 3 is the main part of the main part showing the second embodiment of the invention. FIG. 4 is a half-sectional view of the main part showing the fourth embodiment of the present invention, and FIG. 5 is a half-sectional view of the main part showing the fifth embodiment of the present invention. FIG. 6 is a half-sectional view of the main part showing a sixth embodiment of the present invention, and FIG. 7 is a half-sectional view of the main part showing the exhaust pipe structure of a conventional internal combustion engine. 1...Muffler body, 11, 21, 31, 41,
51, 61...Tail tube, 12, 22, 3
2, 42, 52, 62...finishiya, X...
welded part.

Claims (1)

[Scope of utility model registration request] a tail tube whose one end is connected to the muffler body and whose other end is open to the atmosphere; a finisher that is fitted and fixed to the tail tube and covers the tail tube;
In the exhaust pipe structure for an internal combustion engine, the finisher is positioned so that a portion of the finisher butts against the muffler body or the rear end of the tail tube, and the finisher is positioned on the tail tube so as to cover the joint between the muffler body and the tail tube. An exhaust pipe structure for an internal combustion engine, characterized in that it is fitted and fixed.