JP2002081315A - Coupling structure for double-layered tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coupling method for a double-layered tube capable of coupling end parts of the double-layered tubes by assembling a plurality of end parts without using a coupling member and without changing cross sectional shapes of inner tubes, maintaining the interval of the inner tubes and outer tubes constant at the end parts of the double-layered tubes. SOLUTION: Plane parts 4 to be joined by being brought into face contact with each other are formed on side surfaces of the outer tubes 3 without changing the shapes of the inner tubes 2 at end parts of the double-layered tubes 1 constituted of the inner tubes 2 and the outer tubes 3 provided in constant space provided states at the outside. The end part of each of the double-layered tubes 1 is assembled so that the plane parts 4 formed on the side surfaces of the outer tubes 3 may be turned inside and each of the plane parts 4 is joined by being brought into face contact with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting structure for a two-layer pipe, and more particularly, to a plurality of ends of a two-layer pipe used for an intake manifold or an exhaust manifold of a vehicle air intake / exhaust device. For connecting two-layer pipes.

[0002]

2. Description of the Related Art In a vehicle such as an automobile, a two-layer pipe used as a flow path for gas such as exhaust gas is provided with an inner pipe through which a gas flows and at a certain interval outside the inner pipe. Equipped with an outer tube.

[0003] Conventionally, as shown in FIG.
The inner tube 12 and the outer tube 13 are used to collect and join the ends.
Are formed so that both cross-sectional shapes of the outer tube 13 are sector-shaped.
A flat portion 14 is formed on the side surface of. Then, the flat portions 14 are brought into surface contact with each other and joined, whereby a plurality of ends of the two-layer tube 11 are assembled and joined. In addition, the reason why the sectional shapes of the inner tube 12 and the outer tube 13 are both fan-shaped is that the inner tube 12 and the outer tube 1
This is for keeping the interval with No. 3 constant.

However, in the prior art shown in FIG. 6, the inner pipe 12 having an originally circular cross-sectional shape is reduced in diameter at the end of the double-layer pipe 11 so that the cross-sectional shape changes into a fan shape. 1
At one end, there was a problem that the flow of gas flowing through the inner tube 12 became worse.

Therefore, as shown in FIGS. 7A and 7B, the sectional shape of the inner tube 22 and the outer tube 23 is changed at the end of the double-layer tube 21 by using the connecting member 24. Not
A conventional technique in which a plurality of ends of the double-layer pipe 21 are assembled and connected is used.

[0006] The coupling member 24 has the same number of insertion holes 25 through which the ends of the double-layer pipe 21 are inserted as the number of double-layer pipes 21 to be assembled. By inserting the portions, a plurality of ends of the two-layer tube 21 are assembled and connected.

[0007]

However, in the prior art shown in FIG. 7, since the connecting member 24 is used, the number of parts is increased, the cost is increased, and the weight of the entire vehicle is increased. .

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and does not use a connecting member, and maintains a constant distance between the inner pipe and the outer pipe at the end of the two-layer pipe. It is an object of the present invention to provide a method for joining two-layer pipes, in which a plurality of ends of a two-layer pipe can be assembled and joined without changing the cross-sectional shape of the two-layer pipe.

[0009]

According to the present invention, a plurality of end portions of a two-layer tube having an inner tube through which a gas flows and an outer tube provided at a predetermined interval outside the inner tube are assembled. A joint structure of a two-layer pipe that is joined by being brought into contact with the side surface of the outer pipe at the end of the two-layer pipe without changing the cross-sectional shape of the inner pipe. The configuration was such that a portion was formed. With this configuration, the cross-sectional shape of the inner tube is changed at the end of the two-layer tube without using a coupling member and while maintaining a constant distance between the inner tube and the outer tube at the end of the two-layer tube. Without causing the end portions of the two-layer tube to be assembled together, they can be joined together.

Further, the end of the outer tube is enlarged in diameter, and the end of the outer tube is formed to have a fan-shaped cross section, and the apex angle of the fan is 360 / n degrees (n is the number of double-layer tubes). The flat portion is formed at a position on both sides of the apex angle. With such a configuration, it is possible to form, at the end of the two-layer tube, a flat portion on the side surface of the outer tube, in which a plurality of ends of the two-layer tube can be easily assembled.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. The two-layer tube 1 shown in FIG.
For example, it is a two-layer pipe used for an exhaust manifold or the like of a vehicle, and ends of the two-layer pipes 1 are collectively connected. Hereinafter, as an example, a case will be described in which the ends of four double-walled tubes 1 are assembled and joined, but the number of double-walled tubes 1 is not particularly limited.

FIG. 2 is a view taken in the direction of the arrow I in FIG. Double-layer pipe 1
Consists of an inner tube 2 and an outer tube 3 provided outside the inner tube 2 at a predetermined interval. When this double-layer pipe 1 is used for an exhaust manifold of a vehicle, exhaust gas discharged from each cylinder of the engine of the vehicle flows through the inner pipe 2.

The inner tube 2 is formed so as to have a circular cross section, and the circular cross section is maintained from the exhaust inflow side to the exhaust outflow side. In other words, the cross-sectional shape of the inner tube 2 does not change at the end portion 2, and the flow velocity of the gas flowing through the inner tube 2 and the like are kept uniform throughout.

The outer tube 3 is formed so that its cross section other than the end is circular. The inner tube 2 is arranged inside the outer tube 3 at a predetermined interval. Then, as shown in FIG. 3 which is a perspective view of the end of the double-layer pipe 1,
It is formed so that its diameter increases toward the front end, which is the exhaust outlet side, and its cross-sectional shape is a sector.

Therefore, on the side surface of the end of the outer tube 3, a flat portion 4 is formed at a position corresponding to both surfaces of the fan-shaped apex angle,
The curved surface portion 5 is formed on a surface corresponding to the sectoral arc. That is, two plane portions 4 are formed adjacent to the side surface of the outer tube 3 at a predetermined angle.

As shown in FIG. 3, the flat portion 4 is formed in a rectangular shape here, and the fan-shaped radius is defined as the horizontal side of the rectangle, and a predetermined radius is defined in the axial direction of the outer tube 3 from both ends of the horizontal side. Is formed as a vertical side of the rectangle. The flat portion 4 is formed so as to have an area enough to make a sufficient surface contact when joined to the flat portion 4 of another two-layer tube 1, and its shape is not particularly specified. .

The cross section of the end of the outer tube 3 is formed such that the vertical angle 6 of the fan is 360 / n degrees (n is the number of double-layer tubes). Therefore, as shown in FIG. 2, when the ends 2 of the four double-layer pipes 1 are assembled and connected, the outer pipe 3
Are formed such that the apex angle 6 of the sector is 90 degrees, and the plane portions 4 are formed at positions on both sides of the apex angle 6.

When assembling and joining the ends of the four double-walled tubes 1 configured as described above, first, the ends of each double-layered tube 1 are connected to the side surface of the end of the outer tube 3. Are assembled so that the flat portion 4 formed on the inner side is located inside. Then, the flat portions 4 at the positions facing each other are brought into surface contact with each other and joined.

Then, the ends of the two-layer pipe 1 are joined by welding the corners 7 of the flat part 4 joined to each other.
Here, welding is used for joining the ends of the two-layer pipe 1 to each other, but the method for joining the ends of the two-layer pipe 1 is not particularly limited, and the method for joining the two ends is not particularly limited. The ends of the layer tube 1 can be connected by, for example, an adhesive or the like.

As shown in FIG. 4, two double-layer tubes 1
Are assembled and combined, the end of the outer tube 3 is formed such that the vertical angle 8 of the fan having a sectional shape becomes 180 degrees. That is, since the radius of the fan is continuously linear, the cross-sectional shape of the outer tube 3 is formed in a semicircular shape.

When the two-layer pipe 1 is used for an exhaust manifold of a vehicle, the ends of the two-layer pipes 1 that are assembled and joined together are formed as shown in FIG. It is fitted and fixed to one end 9 of the monaka 8. A two-layer pipe (not shown) connected to the muffler is fitted and fixed to the other end 10 of the two-layer monaka 9. Therefore, the exhaust gas flowing through the inner pipe 2 of the two-layer pipe 1 is exhausted to the muffler.

Here, as shown in FIG. 3, as one embodiment, the outer tube 3 is formed by expanding the diameter of the outer tube 3 at the end of the double-layer tube 1, but the inner tube 2 and the outer tube 3 are formed in advance. If the space is provided widely, the flat portion 4 can be formed on the side surface of the outer tube 3 without expanding the outer tube 3 at the end of the two-layer tube 1.

Here, as shown in FIGS. 2 and 3, as one embodiment, the cross-sectional shape of the end of the outer tube 3 is formed into a sector shape. ,In particular,
It is not limited to a fan shape. If the space between the inner tube 2 and the outer tube 3 is provided widely in advance, the outer tube 3
May be formed, for example, in a square shape.

[0024]

From the above, according to the present invention, according to the present invention, the cross-sectional shape of the outer tube is not changed at the end of the double-layer tube at a constant interval outside the inner tube without changing the cross-sectional shape of the inner tube. By forming a flat portion on the side surface for surface contact with each other and joining, it is possible to use a two-layer structure without using a coupling member and maintaining a constant distance between the inner tube and the outer tube at the end of the two-layer tube. A plurality of ends of the two-layer tube can be assembled and easily connected without changing the cross-sectional shape of the inner tube at the end of the tube. Therefore, the flow velocity of the gas flowing through the inner tube and the like are kept constant without changing throughout.

Further, the outer tube of the double-layer tube is expanded in diameter toward the tip, and the cross-sectional shape of the end of the outer tube is formed into a sector shape, and the apex angle of the fan is 360 / n degrees (n is two-layer tube). The number of pipes) makes it possible to form a flat surface on the side of the end of the outer pipe while keeping the distance between the inner pipe and the outer pipe constant, making it easier to assemble the ends of the two-layer pipe. Becomes

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a combined structure of a two-layer tube of the present invention.

FIG. 2 is a view taken in the direction of the arrow I in FIG. 1;

FIG. 3 is a perspective view showing an end of a two-layer tube.

FIG. 4 is a cross-sectional view showing a state in which ends of two two-layer pipes are assembled and connected.

FIG. 5 is a perspective view showing a state in which an end of a two-layer tube is fitted and fixed to a two-layer Monaca.

FIG. 6 is a cross-sectional view showing a conventional connection structure of a two-layer tube.

FIGS. 7A and 7B are a cross-sectional view and a II-II cross-sectional view showing a state in which a plurality of ends of a two-layer pipe are assembled and connected using a conventional connecting member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Double-layer pipe 2 Inner pipe 3 Outer pipe 4 Plane part 5 Curved surface part 6 Apex angle 7 Corner

Claims (2)

[Claims] 1. A two-layer pipe in which a plurality of ends of a two-layer pipe including an inner pipe through which a gas flows and an outer pipe provided at a predetermined interval outside the inner pipe are assembled and connected. A flat portion for joining the side surfaces of the outer tube to each other at the end of the double-layer tube without changing the cross-sectional shape of the inner tube. A coupling structure of a two-layer tube, characterized in that: 2. An end of the outer tube is enlarged in diameter to form a sectional shape of the end of the outer tube into a sector, and the apex angle of the sector is 360 / n degrees (n is a double-layered tube). 2. The two-layer pipe connecting structure according to claim 1, wherein the flat portion is formed at a position on both sides of the apex angle.