JP2000240444A - Exhaust pipe structure of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of the branch of an exhaust device by a method wherein the inlet parts of downstream exhaust pipes is inserted in the outlet part of an upper stream exhaust pipe. SOLUTION: A branch part 20 is formed in an extremely simple shape that the inlet parts 31L and 31R of left and right downstream exhaust pipes 30L and 30R are inserted in the outlet part 22 of an upper stream exhaust pipe 21, and in more details, insertion is effected that the axes 32L and 32R of the downstream exhaust pipes 30L and 30R parallels the axis 23 of the upper stream exhaust pipe 21 and coupling is effected at a weld part 35. The left and right downstream exhaust pipes 30L and 30R are bundled together by a coupling member 40. Since the two downstream exhaust pipes are intercoupled by a coupling member, when a force when the muffler is vibrated is not exerted on the branch part and the weld part, the downstream exhaust pipe itself is decreased in thickness and size, and a decrease in the weight of the branch part is achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving an exhaust pipe structure of a vehicle.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing the principle of a conventional branch type exhaust pipe structure.
2 at the branching section 103 into two downstream exhaust pipes 104L, 10L.
4R (L indicates left, R indicates right; the same applies hereinafter),
A branch type exhaust pipe structure in which silencers 105L and 105R are attached to ends of these downstream exhaust pipes 104L and 104R, respectively, is shown. 106 is a catalyst device.

FIG. 8 is an exploded perspective view of a conventional branch portion.
A typical branch 103 is a Y-shaped upper joint plate 1
07 and the lower joint plate 108 are welded together, and the joint plates 107 and
It has a structure of welding to 104L and 104R.

[0004]

SUMMARY OF THE INVENTION
When the silencers 105L, 105R (see FIG. 7) vibrate, they must be strong so that the welded parts do not peel off. Specifically, the plate thickness of the upper and lower joint plates 107, 108 is increased, and Measures such as increasing the thickness of the exhaust pipes 102, 104L, 104R are taken. When the thickness of the plate or the thickness of the pipe increases, the amount of metal deposited by welding must be increased. As a result, the number of welding steps increases and the overall weight increases, leading to an increase in manufacturing cost. Accordingly, an object of the present invention is to improve the structure of the branch portion to reduce the weight.

[0005]

In order to achieve the above object, a first aspect of the present invention is to connect one upstream exhaust pipe to a second exhaust pipe via a branch.
In the exhaust pipe structure of a vehicle which branches into two downstream exhaust pipes and a muffler is attached to each end of these downstream exhaust pipes, the branch section is provided at the inlet of the downstream exhaust pipe at the axis of the outlet of the upstream exhaust pipe. The downstream exhaust pipes are connected to each other by a connecting member to keep the inlets of the two downstream exhaust pipes right and left, and the inlet of such a downstream exhaust pipe is connected to the outlet of the upstream exhaust pipe. It is characterized in that it is configured to be inserted.

[0006] Since the axes of the two left and right downstream exhaust pipes are made parallel to the axis of the upstream exhaust pipe, the exhaust gas diverges with little change in direction. Also, since the two left and right downstream exhaust pipes are connected by the connecting member, the force when the muffler vibrates does not act on the branch portion or the welded portion, and the downstream exhaust pipe itself can be made thinner and smaller in diameter, Lightening of the branch can be achieved.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a side view of a vehicle equipped with an exhaust device according to the present invention. An open car 10 as a vehicle includes a front wheel 12 and a rear wheel 13 in front and rear of a vehicle body 11, and has an exhaust device under the floor like a general passenger car. 15 and has a structure for exhausting exhaust gas from the lower rear portion of the vehicle body 11. The general configuration of the exhaust device 15 has been described in the section of the related art, and thus will not be described.

FIG. 2 is a plan view of a branch portion of the exhaust system according to the present invention.
2, the inlet portions 3 of the two left and right downstream exhaust pipes 30L, 30R.
1L and 31R are inserted. Specifically, the axes 32L and 32 of the downstream exhaust pipes 30L and 30R are inserted into the axis 23 of the upstream exhaust pipe 21.
This is an extremely simple shape in which R is inserted in parallel so as to be joined together at the welded portion 35.

Reference numeral 36 denotes a fillet weld bead which is formed by shifting the tips of the left and right inlet portions 30L and 30R and welding the corners thereof in the front and rear directions in the drawing. The bead 36 has the left and right inlet portions 30L and 30L. 30R and a function of closing the gap between the left and right inlet portions 30L and 30R. Reference numeral 40 denotes a bridge member as a connecting member for bundling the left and right downstream exhaust pipes 30L and 30R, and details thereof will be described later.

As is apparent from the figure, the exhaust gas flowing through the upstream exhaust pipe 21 as shown by the arrows is branched as shown by arrows. However, since the directions of these arrows are the same as the directions of the arrows, the branch flow is smooth. And the so-called shunt loss is very small.

FIG. 3 is a side view of a branch portion of the exhaust system according to the present invention. The rear end of the upstream exhaust pipe 21 is composed of a cylindrical portion 25, a reducer portion 26, and an outlet portion 22. This shows that the inlet portions of the downstream exhaust pipes 30L and 30R are inserted into the portion 22. In addition, a structure is adopted in which the two downstream exhaust pipes 30L, 30R are bundled by a pair of upper and lower bridge members 40, 40. The bridge member 40 is provided with a flange 41 formed by bending and has a high rigidity.

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3, and the right inlet 31R is a non-circular cross section formed by closing the U cross section 33 with the I cross section 34. In addition, the U cross section 33 has a semicircular portion 33a with a radius r, and two upper and lower linear portions 33 in detail.
b and 33b are continuous. Such a non-circular cross section can be easily manufactured by plastically processing a round tube. Or it is also possible to manufacture directly from a billet by extrusion. Therefore, the method of manufacturing the inlet 31R of the downstream pipe is optional. Similarly, the left inlet portion 31L is also a non-circular cross-sectional body formed by closing the U cross section 33 with the I cross section 34.

The outlet portion 22 of the upstream exhaust pipe is formed by connecting two semicircular portions with two parallel straight portions so that the inlet portions 31L and 31R of the overlapped downstream exhaust pipe can be inserted. It is an oval shape.

FIG. 5 is a sectional view taken along the line 5-5 in FIG. 3, in which the upper bridge member 40 is passed over the inlet portions 31L, 31R of the superposed downstream exhaust pipe, and is fixed to the right inlet portion 31R by a bead 42. , And bead 43 is fixed to left entrance portion 31L. The same applies to the lower bridge member 40. Thus, the left and right inlet portions 31L and 31R can be firmly bundled. A non-welded portion 44 is provided between the beads 42 and 43. This is to avoid interference with the center bead 45 (see also FIG. 2) which directly joins the left and right inlet portions 31L, 31R. In addition, the welding length is shortened by the non-welded portion 44, so that the number of welding steps can be reduced.

FIGS. 6A to 6D are views for explaining a method of manufacturing a branch portion according to the present invention. Note that the manufacturing method described here is an example, and the order may be changed. (A): Downstream exhaust pipes 30L, 30R previously made non-circular in cross section
I sections 34, 34 of the inlet sections 31L, 31R are overlapped with each other (arrows). (B): The inlet portions 31L and 31R of the downstream exhaust pipe are joined to each other by welding. 45 is a center bead, 46 is a welding rod or welding electrode. Then, the bridge members 40, 40 are set (arrows).

(C): The bridge members 40, 40 are welded to the downstream exhaust pipes 30L, 30R. 42 and 43 are beads. And it inserts in the outlet part 22 of the upstream exhaust pipe 21 previously shape | molded in the shape of an ellipse (arrow). (D): Then, the upstream exhaust pipe 21 and the downstream exhaust pipe 30L,
30R are joined by a weld 35. Here, bridge material 4
0, 40 are provided with flanges 41, 41, so that not only tension but also torsional rigidity are high, and the downstream exhaust pipes 30L, 30
It exerts an effect of effectively suppressing R from shifting up and down and left and right.

That is, since the left and right downstream exhaust pipes 30L, 30R are integrated by the bridge members 40, 40, there is no concern that the downstream exhaust pipes 30L, 30R are separated even if the exhaust system vibrates. If there is no bridge material 40, 40, the downstream exhaust pipe 3
In order to increase the rigidity of 0L and 30R, measures such as increasing the wall thickness or increasing the diameter must be taken.
By employing the bridge members 40, 40, there is no need for this, and the thickness and diameter of the downstream exhaust pipes 30L, 30R can be reduced.

The bridge members 40, 40 are replaced by the above (b)
Instead of mounting at (d), it may be mounted after (d).
Therefore, FIG. 6 shows an example of an assembling method. In short, as long as the configuration of FIG. 2 is completed, the assembling order and the processing method are not particularly limited.

The shape of the connecting members 40, 40 is arbitrary as long as they can connect the left and right downstream exhaust pipes 30L, 30R. For example, a hose band, a belt, a ring, a simple band plate or a bar can be used. And it is not limited to a bridge material. In addition, the shape of the inlet portion of the downstream exhaust pipe is not limited to the U cross section + I cross section of this embodiment, but a semicircular cross section +
The section I may be a rectangular section, and such downstream exhaust pipes may be arranged side by side on two sides and bound by a connecting member and inserted into the inlet section of the upstream exhaust pipe. The shape is arbitrary. However, if the section is U section + I section of the present embodiment, the inlet of the upstream exhaust pipe can be made oblong and oblong, which is convenient for increasing the ground clearance of the vehicle.

Further, in this embodiment, the sum of the opening area of the inlet of the downstream exhaust pipe and the opening area of the outlet of the upstream exhaust pipe are matched, but the two downstream exhaust pipes are provided at the outlet of the upstream exhaust pipe. In order to achieve this, the outlet of the upstream exhaust pipe may be slightly enlarged, and the downstream exhaust pipe may be inserted therein, and the gap may be closed by another member. In short, since the axes of the inlets of the two left and right downstream exhaust pipes may be arranged parallel to the axis of the outlet of the upstream exhaust pipe, the cross section between the outlet of the upstream exhaust pipe and the inlet of the downstream exhaust pipe may be used. The shape can be changed. However, if the sum of the opening area of the inlet portion of the downstream exhaust pipe and the opening area of the outlet portion of the upstream exhaust pipe match as in the present embodiment, a separate member for sealing is not required, so that The number of points and the manufacturing cost can be reduced.

[0021]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, the axes of the two right and left downstream exhaust pipes are made parallel to the axis of the upstream exhaust pipe, so that the exhaust gas can be divided without changing the direction, and so-called diversion loss is reduced. And the exhaust gas can flow extremely smoothly. In addition, since the left and right downstream exhaust pipes are connected by a connecting member, the force when the silencer vibrates does not act on the branch or welded part, and the downstream exhaust pipe itself can be made thinner and smaller in diameter. The weight of the branch can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a vehicle equipped with an exhaust device according to the present invention.

FIG. 2 is a plan view of a branch portion of the exhaust device according to the present invention.

FIG. 3 is a side view of a branch portion of the exhaust device according to the present invention.

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 in FIG. 3;

FIG. 6 is a diagram illustrating a method for manufacturing a branch portion according to the present invention.

FIG. 7 is a principle diagram of a conventional branch type exhaust pipe structure.

FIG. 8 is an exploded perspective view of a conventional branch portion.

[Description of Signs] 10 ... Vehicle (open car), 15 ... Exhaust device, 20 ...
Branch, 21 ... Upstream exhaust pipe, 22 ... Outlet, 23 ... Outlet axis, 30L, 30R ... Downstream exhaust, 31L, 31
R: entrance, 32L, 32R: axis of entrance, 33: U
Cross section, 34 ... I cross section, 35 ... Weld, 40 ... Coupling member (bridge material).

Claims (1)

[Claims] 1. One upstream exhaust pipe is connected via a branch to a second exhaust pipe.
In the exhaust pipe structure of a vehicle which branches into two downstream exhaust pipes and a muffler is attached to each end of these downstream exhaust pipes, the branch section is provided at the inlet of the downstream exhaust pipe at the axis of the outlet of the upstream exhaust pipe. The downstream exhaust pipes are connected to each other by a connecting member to keep the inlets of the two downstream exhaust pipes right and left, and the inlet of such a downstream exhaust pipe is connected to the outlet of the upstream exhaust pipe. An exhaust pipe structure for a vehicle, wherein the exhaust pipe structure is inserted.