JP3375441B2 - Exhaust pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust collecting pipe suitable for a collecting portion of two exhaust pipes.

[0002]

2. Description of the Related Art There is an exhaust pipe structure in which exhaust gas is guided from an engine by a plurality of exhaust pipes and then the exhaust pipes are assembled. As the collecting pipe in this case, a Y-shaped pipe having two inlets and one outlet is usually adopted.
The 47708 publication "Exhaust junction tube" has been proposed. This joint pipe has a rectifying plate inside to prevent exhaust gases from colliding with each other and avoid interference. Alternatively, a so-called double-pipe structure where a small-diameter exhaust pipe is inserted into a large-diameter exhaust pipe is proposed in, for example, Japanese Utility Model Laid-Open No. 63-130614, "Exhaust Gas Purification Device for Internal Combustion Engine".

[0003]

The above-mentioned collecting pipe has a large internal space, so that it is difficult to secure rigidity as compared with the front and rear round pipes. The straightening vanes are cumbersome to attach to the half-divided body and cannot be expected as a strength member. Therefore, it is necessary to increase the plate thickness of the half-split body or the plate thickness of the straightening vane as compared with the front and rear round tubes. However, if the plate thickness is increased in order to increase the rigidity, the heat capacity (heat mass) increases and the rise in exhaust gas temperature at engine start is suppressed.
If the rise of the exhaust gas temperature is delayed, the purification performance of the catalyst of the exhaust purification device will not be exhibited, which is not convenient.

Since the above-mentioned gathering portion is a combination of round tubes, it is easy to ensure rigidity. This structure requires the inner tube to be properly retained in the center of the outer tube. This is because if the position of the inner pipe is deviated, the flow of exhaust gas on the outer pipe side becomes a lopsided flow and the design cannot be achieved. Therefore, in order to secure the position, it is necessary to take measures such as interposing a large number of spacers between the inner pipe and the outer pipe, which complicates the structure and the spacer narrows the flow passage on the outer pipe side. It is necessary to increase the diameter, which disadvantageously increases the material cost and the manufacturing cost. Therefore, an object of the present invention is to provide an exhaust collecting pipe that can solve the above-mentioned drawbacks.

[0005]

In order to achieve the above object, the present invention is directed to an exhaust collecting pipe for assembling a first pipe and a second pipe through an insertion hole formed in the first pipe. The tip of the second pipe is inserted into the first pipe, and the first pipe is composed of two half-split pipes divided into a split portion passing through the insertion hole and a split portion facing the split portion. By constructing and integrally joining the outer peripheral portion of the inserted second pipe and the divided portion that passes through the insertion hole of the first pipe, it is also possible to join the two half-split pipes together. It is characterized in that the tip of the second tube is bonded and fixed to the first tube.

It is desirable that the flow passage area of the first pipe after the insertion hole is large enough to allow a flow amount equal to the flow amount of the tip portion of the second pipe.

[0007]

Since the second pipe (small-diameter pipe) is inserted into the first pipe (large-diameter pipe) to form the double pipe structure, it is easy to secure rigidity. Since the second tube is integrally joined to the first tube, the position of the second tube is fixed and it is not necessary to add a spacer. Then, when the second pipe is joined to the first pipe at the same time when the half pipes are joined together, the completion of the first pipe and the attachment of the second pipe can be completed in one welding process. .

By matching the flow passage area of the first pipe with the second flow passage area, the flow rate balance of the exhaust gas becomes good.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a layout diagram of an exhaust collecting pipe according to the present invention. Exhaust gas of an engine 1 is exhausted to the rear of the vehicle body through exhaust pipes 2 and 3 and first pipes 5 and 2 attached to both sides. After being sent and merged in the exhaust collecting pipe 10, they are further sent to the rear of the vehicle body via an exhaust purification device (not shown). 7 is a transmission.

FIG. 2 is a plan sectional view of the exhaust collecting pipe according to the present invention. In the exhaust collecting pipe 10, the tip end portion 11 of the first pipe is inserted into the tip end portion 12 of the second pipe through the insertion hole 13. Further, the cover 18 is attached via the mesh spacers 15, 16 and 17. The cover 18 also serves as a flying stone guard and a heat insulating cover. The mesh spacer 1
Reference numerals 5, 16 and 17 are rings knitted with thin stainless wires and have appropriate elasticity and therefore have a function of absorbing a difference in thermal expansion and vibration. Reference numeral 19 denotes a different-diameter pipe, which is attached to the second pipe 6 having a small diameter, so that the mesh spacers 15, 1
6 can be made the same size. Therefore, originally, three kinds of mesh spacers 15, 16 and 17 were required, but by adopting the different-diameter tube 19, it is possible to integrate them into two kinds.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2, in which the tip portion 12 of the second tube is a small-diameter round tube, and the tip portion 11 of the first tube is a divided portion 11a, 11b. The half-split pipes 11c and 11d divided into two are joined together, and the cover 18 is formed by joining the half-split bodies 18a and 18b each including a flange. Further, a part of the outer peripheral surface of the tip end portion 12 of the second pipe abuts on the inner peripheral surface of the tip end portion 11 of the first pipe, and is integrally joined at this abutting portion.

The manufacturing procedure of the above-described exhaust collecting pipe will be described below. FIGS. 4 (a) to 4 (c) are explanatory views of the manufacturing method of the exhaust gas collecting pipe of the present invention, and FIG. 4 (a) is a half split pipe 11c, 11d.
The first pipe 5 is made up of, and the half-divided pipes 11c and 11d have the insertion holes 13 formed in the cutouts and the welding groove slits 21 and 21 formed in the cutouts in advance. The notch may be mechanically cut with a bite, a milling cutter, or the like, or may be punched by a press or the like. Any method may be used as long as the intended recess can be formed. As shown in (b), the half-split pipes 11c, 11
holding the tip portion 12 of the second pipe between d, the half pipe 11c,
11d are overlapped (arrow,). As shown in (c), one of the divided portions 11a is welded in the manner shown by the arrow. With this, the left side of the figure is integrated toward the half-split tubes 11c and 11d. The other divided portion 11b is welded as indicated by the arrow. Since the slit described in (a) is provided here, the welding arc reaches the tip portion 12 of the second pipe sufficiently, and as a result, the half pipe 11c, the half pipe 11d, and the tip portion 12 of the second pipe. The three parties are joined together. For convenience of explanation, the above is explained in a time series, but in principle, they are carried out at the same time.

Since the outer peripheral surface of the tip portion 12 of the second pipe is integrally welded to the inner peripheral surface of the tip portion 11 of the first pipe, the position of the tip portion 12 of the second pipe is determined, and thereafter, the vibration is generated. Even if you receive such things, there is no concern that the position will shift. Further, in (c), the first
The flow passage area and exhaust flow rate of the tip part 11 of the second pipe are S1 and Q1, and the flow passage area and exhaust flow rate of the second pipe tip part 12 are S1 and Q1.
The flow passage area S1 was determined so that Q1 = Q2 when 2 and Q2. The exhaust gas flow rate Q1 is not simply determined because the exhaust gas flows through the crescent-shaped flow path at the tip portion 11 of the first pipe. Therefore, the flow passage area S1 is determined such that the equivalent pipe length (equivalent pipe length) of the first pipe 5 and that of the second pipe 6 are the same. Of course, the flow rate experiment with the real thing or the model is done and S1
It is preferable to confirm.

[0014]

The present invention has the following effects due to the above configuration. In the exhaust gas collecting pipe according to claim 1, since the second pipe (small diameter pipe) is inserted into the first pipe (large diameter pipe) to form a double pipe structure, rigidity is easily ensured, and the first pipe is Since the two tubes are joined together, the position of the second tube is determined, and it is not necessary to add a spacer. Then, when joining the half-split pipes together, the second
Since the first pipe is joined to the first pipe,
Installation of the pipe of can be completed in one welding process,
Manufacturing cost can be reduced.

In the exhaust gas collecting pipe of the second aspect, the flow passage area of the first pipe is matched with the second flow passage area, so that the flow rate balance of the exhaust gas becomes good, which is preferable.

[Brief description of drawings]

FIG. 1 is a layout diagram of an exhaust collecting pipe according to the present invention.

FIG. 2 is a plan sectional view of an exhaust collecting pipe according to the present invention.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is an explanatory diagram of a manufacturing procedure of an exhaust collecting pipe of the present invention.

[Explanation of symbols]

1 ... Engine, 2, 3 ... Exhaust pipe, 5 ... 1st
, 6 ... Second pipe, 10 ... Exhaust collecting pipe, 11 ... First pipe tip portion, 11a, 11b ... Dividing portion, 11c, 11d
... Half-split tube, 12 ... Tip of second tube, 13 ... Insertion hole, 1
5 to 17 ... Mesh spacer, 21 ... Weld groove slit.

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Claims (2)

(57) [Claims] 1. An exhaust collecting pipe for assembling a first pipe and a second pipe, wherein the tip end portion of the second pipe is inside the first pipe through an insertion hole formed in the first pipe. In the exhaust collecting pipe to be inserted into the first exhaust pipe, the first pipe is composed of two half-split pipes divided into a split portion that passes through the insertion hole and a split portion that faces the split portion, and the inserted second pipe. By integrally joining the outer peripheral portion of the pipe and the divided portion passing through the insertion hole of the first pipe, the second pipe is joined to the first pipe when joining the two half-split pipes. An exhaust collecting pipe characterized in that the tips of the pipes are bonded and fixed. 2. The flow path area of the first pipe after the insertion hole is of a size that allows a flow rate equivalent to the flow rate of the tip portion of the second pipe to flow. 1
Exhaust collecting pipe described.