JPH0221544Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an exhaust system for a dual muffler type engine in which the downstream side of an exhaust passage is formed into two exhaust pipes.

(Prior art) Conventionally, in an automobile engine, in order to reduce exhaust noise and increase exhaust efficiency, two-way exhaust gas is connected to the downstream side of the exhaust passage via a bifurcated branch.
BACKGROUND ART A so-called dual muffler type engine exhaust system is known in which two exhaust pipes are formed, each of which is provided with a muffler (see, for example, Japanese Utility Model Application No. 58-64919).

However, such dual muffler type engine exhaust systems generally have the following problems.

That is, in the engine exhaust system having the above structure, the front tube located on the upstream side of the exhaust passage is connected to the two exhaust pipes on the downstream side of the exhaust passage via a bifurcated branch. However, since the above two exhaust pipes are on the free end side, they tend to swing or vibrate relatively easily, and the direction of the swing (vibration) is not constant, so each of the two exhaust pipes They swing or vibrate in the X, Y, and Z directions independently of each other.

Therefore, the stress due to the rocking or vibration is concentrated on the branching portion that is the connecting portion between each exhaust pipe and the front tube side, and an excessive stress is applied thereto. Moreover, this excessive stress is repeatedly applied during the period of use, and as a result, both exhaust pipe branch portions eventually crack due to material fatigue.

(Purpose of the invention) The present invention was made in order to improve the above-mentioned problems, and by connecting two exhaust pipes to each other via a predetermined reinforcing member, the movement of the two is unified. In addition, a reinforcing pipe is interposed between each exhaust pipe and the reinforcing member to absorb and relieve stress concentration, thereby preventing stress from concentrating on both exhaust pipe branches and preventing cracks from forming. The purpose of this invention is to provide an exhaust system for

(Means for Achieving the Object) In order to achieve the above object, the present invention has a single exhaust passage with a downstream side formed into two exhaust pipes via a bifurcated branch, and these two exhaust pipes. The two exhaust pipes are suspended and supported in a swingable manner, and each of the two exhaust pipes is fitted with a reinforcing pipe, and each of these reinforcing pipes is further connected to each other by a reinforcing bracket member. The reinforcing pipe and the exhaust pipe are integrally connected to each other at the end portion of the fitting portion on the side of the branch portion.

(Function) For this reason, the separate rocking or vibration of the two exhaust pipes, which conventionally acted directly on the branching part, is integrated by the reinforcing bracket member, and the respective exhaust pipes are fitted into each other. Vibration or rocking is suppressed by the reinforcing pipe installed. Therefore, the concentration of stress on the exhaust pipe branch portion is alleviated. In addition, since the reinforcing pipe and the exhaust pipe are joined at the ends on the branch side, thermal expansion and contraction of both exhaust pipes is released to the free end side (exhaust outlet side), and the reinforcing pipe and both exhaust pipes are The generation of thermal stress at the joint is prevented.

(Example) The drawings show a preferred embodiment of the present invention, and FIG. 1 is a plan view showing the overall configuration of an engine exhaust system according to the embodiment, and FIG. The enlarged sectional view of the main part (- part), Fig. 3 is the
It is a view taken along arrow A in the figure.

First, in FIG. 1, reference numeral 1 denotes an engine, and an exhaust manifold 2 is provided in communication with exhaust ports of each cylinder of the engine 1. As shown in FIG. The exhaust manifold 2 is connected to a catalytic converter 4 via a single front tube 3. The exhaust pipe on the downstream side of the catalytic converter 4 is bifurcated at a branch portion 5 into two exhaust pipes 6a and 6b. A silencer 7 is provided in each of these exhaust pipes 6a and 6b.
a and 7b are connected. In addition, codes 8a, 8
b is a rear tube with a diffuser provided in the silencers 7a and 7b.

Therefore, the exhaust gas from each cylinder of the engine 1 that is discharged through the exhaust manifold 2 is first collected in common through the front tube 3 and then guided to the catalytic converter 4, where the exhaust gas is purified. After that, go through branch 5 and continue to 2.
Guided to book exhaust pipes 6a, 6b, silencers 7a, 7
After passing through b, the sound is muffled and then released into the atmosphere from the rear tube 8.

On the other hand, reference numerals 10a and 10b indicate sleeve-shaped reinforcing pipes fitted into the two exhaust pipes 6a and 6b, respectively, and are provided at a predetermined distance on the exhaust downstream side with respect to the branch portion 5. At the same time, they are connected and fixed to each other by a reinforcing bracket member 11. That is, the reinforcing bracket member 1
1, as shown in FIG.
It is made up of a band-shaped body formed by bending two fitting recesses 12a and 12b with inner diameters corresponding to the outer diameters of 0a and 10b, and through holes 13a to 13c for bolt insertion are formed at both ends and the center, respectively. has been done. Then, the reinforcing bracket member 11 is
Upper ends 14a, 14 of the fitting recesses 12a, 12b
At b, the exhaust pipe protector 26 is welded to the reinforcing pipes 10a and 10b from below using the through holes 13a to 13c, and is integrally fixed with the protector 26 via bolts 15.

Further, in the above state, the reinforcing pipes 10a and 10b are connected to the exhaust pipes 6a and 6b at the end portions on the side of the branch portion 5 with respect to the corresponding exhaust pipes 6a and 6b, respectively, as shown in FIG. It is spot welded or all around welded (FIG. 3 shows only one exhaust pipe 6b side).
Reference numeral 16 is the joint portion thereof.

In addition, in FIG. 1, numerals 17 to 25 respectively indicate elastic locking portions (hanger portions) at respective portions toward the vehicle body.

Therefore, the two exhaust pipes 6a, 6b are prevented from separate vibration or swinging motion by the reinforcing bracket member 11, and their movements relative to the branch portion 5 are integrated, so that the two exhaust pipes 6a and 6b are not particularly affected by the branch portion. 5
does not become a stress concentration point. Moreover, when the two exhaust pipes 6a and 6b are integrated with the reinforcing bracket member 11, the reinforcing bracket member 11 connects the exhaust pipes 6 to each other through the reinforcing pipes 10a and 10b.
Further, the reinforcing pipes 10a, 10b themselves are joined to the exhaust pipes 6a, 6b (reference numeral 16) only at the end on the side of the branching part 5 at the fitting part for each exhaust pipe 6a, 6b. Therefore, expansion and thermal contraction due to temperature changes of each exhaust pipe 6a, 6b can be released to the free end side (exhaust outlet side) of each exhaust pipe 6a, 6b, and as a result, each exhaust pipe 6a, 6b Excessive thermal stress is prevented from being generated between the reinforcing pipes 10a and 10b. In addition, by welding only the joint 16 on one end side as described above, the welding heat input to the exhaust pipes 6a, 6b themselves can be reduced, and the strength of the exhaust pipes will not be reduced. There are merits.

Further, since the reinforcing bracket member 11 is connected to the reinforcing pipes 10a and 10b, it is not directly exposed to exhaust heat, so even if a material with low heat resistance is used, there is little thermal deterioration and the durability can be improved. can.

(Effect of the invention) As explained above, in the invention of the present application, the downstream side of one exhaust passage is formed into two exhaust pipes via a bifurcated branch, and these two exhaust pipes swing. On the one hand, each of the two exhaust pipes is fitted with a reinforcing pipe, and these reinforcing pipes are further connected to each other by a reinforcing bracket member, and the above-mentioned The reinforcing pipe and the exhaust pipe are integrally joined at the end portion of the fitting portion on the side of the branch portion.

Therefore, according to the present invention, first, the reinforcing bracket member is used to prevent the stress caused by the individual rocking or vibration of the two exhaust pipes from acting directly on the branching part, and also to integrate the movement of the two exhaust pipes. In particular, it is possible to eliminate stress concentration at the branch portion.

Next, the reinforcing bracket member is connected to the exhaust pipe via the reinforcing pipe, and the reinforcing pipe is joined to the exhaust pipe only at the end of the fitting portion on the side of the branching part. As a result, each exhaust pipe can release its thermal expansion or contraction to the free end side, which is the exhaust outlet side, and prevent excessive thermal stress from occurring at the joint between each exhaust pipe and the reinforcing pipe. At the same time, since the welding input to each exhaust pipe can be reduced, thermal deformation thereof can also be prevented.

Therefore, excessive stress will not be concentrated at any part of the exhaust pipe branch or the joint of the reinforcing pipe, and the occurrence of cracks can be reliably prevented.

In addition, since the exhaust pipe and the reinforcing bracket member are connected via the reinforcing pipe, even if a material with low heat resistance is used, the reinforcing bracket member is less likely to deteriorate due to exhaust heat and its durability is improved. be.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an engine exhaust system according to an embodiment of the present invention, and FIG.
The enlarged line sectional view, FIG. 3, is a view taken along arrow A in FIG. 2. 3... Front tube, 5... Branch, 6
a, 6b... Exhaust pipe, 7a, 7b... Silencer, 1
0a, 10b...Reinforcement pipe, 11...Reinforcement bracket member, 16...Joint portion, 26...Protector.

Claims (1)

[Scope of utility model registration request] The downstream side of one exhaust passage is formed into two exhaust pipes via a bifurcated branch, and these two exhaust pipes are suspended and supported so as to be swingable; A reinforcing pipe is fitted into each of the reinforcing pipes, and these reinforcing pipes are further connected to each other by a reinforcing bracket member, and the reinforcing pipe and the exhaust pipe are connected to the branch part at the fitting part. An engine exhaust system characterized by being integrally joined at a side end.