JP2000204943A - Method for intercoupling flow passage division pipes different in diameter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coupling method to prevent the occurrence of a trouble when flow division pipes different in diameter are relatively displaced. SOLUTION: At an expansion process, the vicinity of the slit groove 22c of a second pipe 20 is expanded and caused to approximately coincides with the diameter of a first pipe 10. At a consecutive covering process, the end part of a second partition plate 22 is covered with a covering member 30 having an arcuate recessed part 31 recessed in an arcuate shape with high precision. At a consecutive coupling process, a first and second pipes 10 and 20 are relatively displaceably intercoupled through a ball joint. In this case, an end part 12b on the first pipe side and an arcuate recessed part 31 on the second pipe side are arranged with a given distance (d) therebetween, and arranged such that both of them form the circular arc of a concentric circle centering around a point Ce. Therefore, even when the second pipe 20 is rotated around the point Ce and displaced due to vertical vibration of a vehicle, the arcuate recessed part 31 is displaced with the given distance (d) kept between the arcuate recessed part and the end 12b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting relatively relatively displaceable pipes having different diameters (pipe whose interior is divided into two flow paths by a partition plate).

[0002]

2. Description of the Related Art Conventionally, as a connecting structure of a flow path dividing pipe whose inside is divided into two flow paths, Japanese Patent Laid-Open No. 9-2506 discloses
The one disclosed in Japanese Patent Publication No. 78 is known. In this connection structure, as shown in FIG.
10 and the second pipe 120 on the downstream side are relatively displaceably connected by a ball joint. And
An arc-shaped convex portion 115 bulging in an arc shape is provided at an end portion of the first partition plate 112, and an arc-shaped concave portion 125 concaved in an arc shape is provided at an end portion of the second partition plate 122. Arc-shaped convex part 1
15 and the arc-shaped concave portion 125 are both arranged on a concentric circle centered on a point Ce (point at the center of the spherical portion of the connecting flange 123), and the arc-shaped convex portion 115 and the arc-shaped concave portion 125 are separated by a predetermined distance d. Are located. When vibration in the vertical direction of the vehicle is transmitted to this connection structure, the second pipe 120 on the downstream side moves in the vertical direction around the point Ce, that is, in FIG.
Vibration in the direction of the white arrow in FIG.
Since 5 and the arc-shaped concave portion 125 are formed as concentric circles of the point Ce, they are relatively displaced while maintaining the predetermined distance d.

[0003]

In the case where the diameters of the two flow-path split pipes are the same, the structure disclosed in the above publication can easily cope with such a problem. If the diameter is larger than the diameter of the first pipe, it is necessary to expand the end of the second pipe to match the diameter of the first pipe.

[0004] However, when the end of the second pipe is expanded,
The joint between the second partition plate and the pipe was sometimes broken (a first problem). Further, even if the joint is not broken, the shape of the arc-shaped concave portion is distorted due to the extension of the second partition plate, so that the arc is not an accurate arc. When the shape of the arcuate concave portion is distorted in this way, when the vertical vibration of the vehicle is transmitted and the two pipes are relatively displaced, the partition plates come into contact with each other to generate abnormal noise, There has been a problem that the exhaust gas flowing in the divided flow path is largely separated from each other and interferes with each other, thereby deteriorating the engine performance (second problem).

On the other hand, Japanese Patent Application Laid-Open No. 9-210272 discloses a flow path dividing pipe suitable for expanding or contracting a pipe. This channel dividing pipe is formed by forming a slit groove at an end of a partition plate. According to this, even if the end of the flow path dividing pipe is expanded, the width of the slit groove of the partition plate is widened, so that there is no possibility that the joint between the partition plate and the pipe is broken. Therefore, the first problem described above is solved by this. However, also in this case, the shape of the arcuate concave portion is distorted due to the extension of the partition plate and is not an accurate arc, so that the above-mentioned second problem still remains.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a connecting method which does not hinder the relative displacement between pipes having different diameters. I do.

[0007]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, a first aspect of the present invention is a method of connecting flow dividing pipes of different diameters (in other words, a method of connecting flow dividing pipes of different diameters). In the method of manufacturing the connection structure, the same applies hereinafter), the pipe expansion step, the coating step, and the connection step are performed in this order. However, other steps may be performed before and after each step. In the pipe expansion step, a small-diameter second pipe whose inside is divided into two flow paths by a second partition plate provided at an end with a variable portion that can be extended in a direction substantially orthogonal to the axial direction,
The vicinity of the variable portion is expanded to substantially match the diameter of the first pipe. In the covering step, an end of the second partition plate of the second pipe after the expansion is covered with a covering member having an arc-shaped concave portion formed in advance so as to be concave in an arc shape. When the pipe expansion step is performed, the shape of the end of the second partition plate is distorted, so that it is difficult to finish the end of the second partition plate after pipe expansion so as to have a highly accurate arc. For this reason, in the coating step, a coating member having an arc-shaped recess separately formed in advance into an arc with high precision is prepared,
This covering member covers the end of the second partition plate of the second pipe after the expansion. As a result, at the end of the second partition plate of the second pipe after the expansion, an arc-shaped concave portion formed in an arc with high accuracy is provided. In the connecting step, the first pipe
With the arcuately bulging end of the partition plate and the arcuate recess of the covering member covering the end of the second partition plate of the second pipe arranged concentrically and separated by a predetermined distance, the second pipe is placed in the second pipe. 1
The pipe is connected to be displaced about the center of the concentric circle as an axis. As a method of connecting in this manner, for example, a method of connecting by a well-known ball joint structure or a pin joint structure can be mentioned (the same applies to the second and third aspects of the present invention described below).

According to the above connection method, when the second pipe is relatively displaced with respect to the first pipe, the arc-shaped bulging end on the first pipe side and the arcuate concave section on the second pipe side are formed. Is also a concentric arc, and the second pipe is displaced about the center of the concentric circle, so that the arc-shaped concave portion on the second pipe side maintains a predetermined distance from the arc-shaped bulging end on the first pipe side. It will be displaced as it is. Therefore, even if they are relatively displaced, they do not come into contact with each other and do not largely separate from each other. This point is maintained even if the predetermined distance is set small. In addition, in the pipe expanding step, when the second pipe is expanded, the variable portion of the second partition plate extends, so that the joint between the second partition plate and the second pipe is not broken.

Here, the variable portion may be, for example, one or more slit grooves extending in the axial direction, a wavy portion having peaks and valleys in a direction substantially perpendicular to the axial direction, and a second portion. The material of the partition plate may be selected such that the second partition plate extends with a force weaker than the force that breaks the joint between the second partition plate and the second pipe, and the entire second partition plate may be the variable portion. . Further, when a slit groove is adopted as the variable portion, exhaust gases flowing through the two divided flow paths may interfere with each other via the slit groove. Preferably, the slit groove is closed by a member. Further, the covering member is formed so as to have a two-fold shape, and the back part of the bent portion is formed into an arcuate concave portion. In the covering step, the end of the second partition plate is inserted into the two-fold shape gap of the covering member. Is preferably performed. In this case, the coating process can be performed smoothly.

Next, a second aspect of the present invention is a method of connecting flow dividing pipes having different diameters, in which a pipe expanding step, an adapter mounting step, and a connecting step are performed in this order.
However, other steps may be performed before and after each step. In the pipe expansion step, a portion of the small-diameter second pipe, the inside of which is divided into two flow paths by the second partition plate except for a portion near one end of the pipe, where the second partition plate does not exist is expanded to form the first pipe. With the diameter of In the adapter mounting step, a partition plate adapter whose end is formed to be concave in an arc shape in advance is mounted on a portion of the second pipe after expansion, where the second partition plate does not exist. Divided into In the connecting step, the arcuately swelled end of the first partition plate of the first pipe and the arcuately concave end of the second pipe partition plate adapter after the adapter mounting step are concentrically separated by a predetermined distance. The second pipe is connected to the first pipe such that the second pipe is displaced around the center of the concentric circle.

According to the above connection method, when the second pipe is displaced relative to the first pipe, the end bulging in an arc shape on the first pipe side and the concave portion in the arc shape on the second pipe side. Each of the ends is a concentric circular arc, and the second pipe is displaced about the center of the concentric circle.
The arc-shaped concave end on the pipe side is displaced while maintaining a predetermined distance from the arc-shaped bulged end on the first pipe side. Therefore, even if they are relatively displaced, they do not come into contact with each other and do not largely separate from each other. This point is maintained even if the predetermined distance is set small. In addition, in the pipe expanding step, the portion where the second partition plate does not exist is expanded, so that the joint between the second partition plate and the second pipe is not broken.

Next, a third aspect of the present invention is a method of connecting flow dividing pipes having different diameters, in which a pipe expanding step, a partition plate attaching step, and a connecting step are performed in this order. However, other steps may be performed before and after each step. In the pipe expansion step, the end of the small-diameter second pipe having a hollow inside is expanded to match the diameter of the first pipe. In the partition plate attaching step, the end is formed in advance so as to be concave in an arc shape, and the outer shell is substantially the same as the longitudinal sectional shape of the second pipe after expansion (that is, the shape having a large diameter portion, a tapered portion, and a small diameter portion). The inside of the expanded second pipe is divided into two flow paths by the second partition plate formed so as to match. In the connecting step, the arcuately swelled end of the first partition of the first pipe and the arcuately concave end of the second pipe of the second pipe after the partition plate attaching step are concentrically and in a predetermined manner. The second pipe is connected to the first pipe so as to be displaced around the center of the concentric circle with the first pipe in a state where the pipes are arranged at a distance.

According to the above connection method, when the second pipe is relatively displaced with respect to the first pipe, the end bulging in an arc shape on the first pipe side and the concave portion in the arc shape on the second pipe side. Each of the ends is a concentric circular arc, and the second pipe is displaced about the center of the concentric circle.
The arc-shaped concave end on the pipe side is displaced while maintaining a predetermined distance from the arc-shaped bulged end on the first pipe side. Therefore, even if they are relatively displaced, they do not come into contact with each other and do not largely separate from each other. This point is maintained even if the predetermined distance is set small. In addition, in the pipe expansion step, since the second pipe having a hollow inside is built in each building, no trouble occurs.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a perspective view of a flow dividing pipe having a different diameter, FIG. 2 is a process explanatory view showing each process until a flow dividing pipe of a different diameter is connected in the first embodiment, FIG. FIG. 3 is an explanatory diagram showing a connection structure.

As shown in FIG. 1, the first pipe 10 is a flow dividing pipe whose inside is divided into two flow paths S11 and S12 by a first partition plate 12. The first partition plate 12 is welded to the inner peripheral surface of the pipe at the flange portions 12a, 12a. An end 12b of the first partition plate 12 located at the opening of the first pipe 10 is formed in a shape bulging in an arc shape.

As shown in FIG. 1, the second pipe 20 is a flow path divided pipe whose inside is divided into two flow paths S 21 and S 22 by a second partition plate 22. Is also small. The second partition plate 22 has a flange portion 22.
a and 22a are welded to the inner peripheral surface of the pipe. An end 22b of the second partition plate 22 located at the opening of the second pipe 20 is formed in an arcuate concave shape, and a slit groove 22c is provided at the center of the end. This slit groove 22c extends in a direction substantially orthogonal to the axial direction (FIG. 2).
It functions as a variable part that can be extended in the direction of the arrow (a).

Next, each step until the first and second pipes 10 and 20 are relatively displaceably connected by a ball joint will be described. First, a pipe expansion step is performed (see FIG. 2B). Here, the vicinity of the slit groove 22c of the second pipe 20 is expanded by bulging.
At this time, since the width of the slit groove 22c of the second partition plate 22 is widened and expanded in a direction substantially orthogonal to the axial direction, the joint between the flange portions 22a, 22a and the pipe is not broken. However, the end 22 of the second partition plate 22
As for b, what was in an arc shape before pipe expansion becomes a distorted shape.
After this pipe expansion step, one end of the second pipe 20 is connected to the large diameter portion 20a.
The large diameter portion 20a substantially matches the diameter of the first pipe 10.

Subsequently, a coating step is performed (FIG. 2C).
reference). Here, as shown in FIG. 4, a covering member 30 having a shape obtained by previously folding a metal plate into two is used. The covering member 30 is formed such that the back portion of the bent portion is accurately formed into an arcuate concave shape, that is, an arcuate concave portion 31. In the covering step, the end of the second partition plate 22 is inserted into the folded gap 32 of the covering member 30, and the covering member 30 and the second partition plate 22 are joined by welding. At this time,
The slit groove 22c of the second partition plate 22 is formed by the covering member 30.
To cover the end 22b of the second partition plate 22. After this coating step, an arc-shaped concave portion 31 that is accurately concavely formed in an arc shape is provided at the end of the second pipe 20.

Subsequently, a connecting step is performed (see FIG. 3). First, a connecting flange 13 having a bolt insertion hole 13a is welded to the outer peripheral surface of the end of the first pipe 10, and then a gasket 14 having a substantially hemispherical surface is fitted. Also,
A connection flange 23 having a bolt insertion hole 23a is welded to the outer peripheral surface of the end of the second pipe 20. The connecting flange 23 is formed in a shape that can contact the substantially hemispherical surface of the gasket 14. Then, each connecting flange 13,
First and second pipes 10 and 20 such that
The bolt 4 is inserted from the coupling flange 23 side via the spring 2 in a state where the coupling flange 23 is in contact with the substantially hemispherical surface of the gasket 14, and the nut 6 is attached to the coupling flange 13 side. To conclude. This bolt 4 has a spring retainer 4
a is provided, and the spring 2 is disposed between the spring retainer 4 a and the connecting flange 23. As a result, the first and second
The pipes 10, 20 are connected via a ball joint so as to be relatively displaceable. Specifically, the end portion 12b bulging in an arc shape on the first pipe side and the arc-shaped concave portion 31 concaved in an arc shape on the second pipe side are arranged at a predetermined distance d, and both of them are pointed. The connection is made in a state of being arranged so as to form a concentric arc centered on Ce (see FIG. 3B, a point which is the center of the substantially hemispherical surface of the connection flange 23).

Next, the operation of the connecting structure will be described. When this connection structure is adopted in an automobile, the first pipe 10 is disposed on the upstream side and the second pipe 20 is disposed on the downstream side, and the plate surfaces of the first and second partition plates 12 and 22 are substantially the same as the pipe axis direction. They are arranged so that the direction orthogonal to them substantially coincides with the vertical direction of the vehicle.

In general, the vibration amplitude of the vehicle is the largest in the vertical direction. However, when the vertical vibration of the vehicle is transmitted to this connection structure, the second pipe 20 on the downstream side moves up and down around the point Ce. It vibrates in the direction, that is, the direction of the white arrow in FIG. At this time, both the end portion 12b on the first pipe side and the arcuate concave portion 31 on the second pipe side are concentric arcs centered at the point Ce, and the second pipe 20 is at the point C
Since it is rotated around e and displaced, the arc-shaped concave portion 31 is displaced while maintaining a predetermined distance d from the arc-shaped bulging end portion 12b on the first pipe side. Therefore, even if they are relatively displaced, they do not come into contact with each other and do not largely separate from each other. This point is maintained even if the predetermined distance d is set small. And
Since the vibration at this time is attenuated and absorbed by the spring 2 and the like, large vibration is not transmitted from the first pipe 10 to the second pipe 20.

The two flow paths S1 of the first pipe 10
1 and S12 are two flow paths S2 of the second pipe 20, respectively.
For example, in the case of a four-cylinder engine, exhaust gases from the first and fourth cylinders flow through the passages S11 and S2.
1 and the exhaust gas from the second and third cylinders passes through the flow path S
12, so as to pass through S22. In the present embodiment, since the predetermined distance d can be set small,
There is no possibility that the exhaust gas passing through the flow paths S11 and S21 via the predetermined distance d and the exhaust gas passing through the flow paths S21 and S22 interfere with each other. Further, the covering member 30 is provided with the slit groove 2.
2c, the exhaust gas passing through the flow paths S11 and S21 via the slit groove 22c and the flow paths S21 and S
There is no possibility that the exhaust gases passing through 22 will interfere with each other. In particular, the covering member 30 has a folded shape,
Since the end 22b of the second partition plate 22 is inserted into the slit 22c, the slit groove 22c can be reliably closed.

In the first embodiment, the second partition plate 2
2, one slit groove 22c is provided as a variable part,
A plurality of slit grooves 24 may be provided as shown in FIG. 5, or, as shown in FIG. 6, peaks may be formed in a direction substantially orthogonal to the axial direction (in FIG. 6, a direction indicated by a two-dot chain line). The wavy portion 25 having a shape in which valleys continue may be provided. In the wavy portion 25, the flange portions 22a and 22a extend without peeling off from the pipe due to the increase in the interval between the peak and the valley in the pipe expanding step.

[Second Embodiment] FIGS. 7A and 7B are explanatory views showing the steps up to the connection of the pipes of different diameters according to the second embodiment, and FIG. 8 is an explanatory view showing the connecting structure. Since the first pipe 10 is the same as that of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted. Second pipe 4
0 is a portion 4 near one end as shown in FIG.
5 is a flow channel divided pipe whose interior is divided into two flow channels by a second partition plate 42 except for the first pipe 1.
Less than 0. The second partition plate 42 has a flange portion 42a,
It is welded to the inner peripheral surface of the pipe at 42a.

Next, each process until the first and second pipes 10 and 40 are relatively displaceably connected by the ball joint will be described. First, a pipe expansion step is performed (see FIG. 7B). Here, in order to expand the portion 45 of the second pipe 40 where the second partition plate 42 does not exist by bulging, the flange portion 42a of the second partition plate 42,
The joint between 42a and the inner peripheral surface of the second pipe 40 is not broken. After this pipe expansion step, the first pipe 1 is placed in a portion 45 of the second pipe 40 where the second partition plate 42 does not exist.
A large diameter portion 40a substantially coinciding with the diameter of 0 and a tapered portion 40b that gradually changes from the original diameter to the diameter after expansion are formed.

Subsequently, an adapter mounting step is performed (see FIG. 7C). Here, as shown in FIG. 9, the outer shape of the large-diameter portion 40a and the tapered portion 40
partition adapter 5 formed in a shape corresponding to the shape of b
0 is used. Of the partition plate adapter 50, the large-diameter portion 4
At the end on the side coinciding with the width of 0a, there is provided a concave portion 51 formed so as to be accurately concave in an arc shape. Also,
The partition plate adapter 50 has flange portions 50a, 50a for welding to the inner peripheral surface of the second pipe 40. In the adapter mounting process, the partition plate adapter 50
Is fitted into the large-diameter portion 40a and the tapered portion 40b of the second pipe 40 after expanded, and is welded to the inner peripheral surface of the pipe at the flange portions 50a, 50a in a state where the second partition plate 42 is abutted against the second partition plate 42. As a result, in the second pipe 40, the large-diameter portion 40a and the tapered portion 40b are also divided into two flow paths, and a concave portion 51 that is accurately concave in an arc shape is provided at an end thereof.

Subsequently, a connecting step is performed (see FIG. 8). Since this connection step is the same as in the first embodiment, the same components are denoted by the same reference numerals, and description thereof will be omitted. After this connection step, the end 1 bulging into an arc on the first pipe side.
2b and a concave portion 51 concaved in an arc shape on the second pipe side
Are arranged at a predetermined distance d, and are concentric arcs centered on a point Ce (see FIG. 8B, a point which is the center of the substantially hemispherical surface of the connecting flange 23). It is connected in the state where it was arranged.

Next, the operation of the connecting structure will be described. When this connection structure is adopted in an automobile, the first pipe 10 is disposed on the upstream side and the second pipe 40 is disposed on the downstream side, and the first and second partition plates 12 and 42 and the plate surface of the partition plate adapter 50 are provided. It is arranged so that the direction substantially perpendicular to the pipe axis direction substantially coincides with the vertical direction of the vehicle.

When vibration in the vertical direction of the vehicle is transmitted to this connection structure, the second pipe 40 on the downstream side vibrates in the vertical direction of the vehicle around the point Ce, that is, in the direction of the white arrow in FIG. 8B. I do. At this time, both the end portion 12b on the first pipe side and the concave portion 51 on the second pipe side are concentric arcs centered on the point Ce, and the second pipe 40 is connected to the point Ce.
, The concave portion 51 is displaced while maintaining a predetermined distance d from the arc-shaped bulging end portion 12b on the first pipe side. Therefore, even if they are relatively displaced, they do not come into contact with each other and do not largely separate from each other. This point is maintained even if the predetermined distance d is set small. Since the vibration at this time is attenuated and absorbed by the spring 2 and the like, the first pipe 10
No large vibration is transmitted from the second pipe 40 to the second pipe 40.

Further, in the present embodiment, since the predetermined distance d can be set small, the exhaust gas passing through the flow paths S11 and S41 through the predetermined distance d and the flow paths S21 and S41
There is no possibility that the exhaust gases passing through 42 will interfere with each other. [Third Embodiment] FIGS. 10A and 10B are process explanatory views showing each process up to connecting different-diameter flow dividing pipes of the third embodiment ((a) is a cross-sectional view before a pipe expansion step, and (b) is a pipe expansion). FIG. 11C is a cross-sectional view after the step, (c) is a cross-sectional view after the covering step), FIG.
FIG.

Since the first pipe 10 is the same as that of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted. As shown in FIG. 10A, the second pipe 60 is a hollow pipe, and the diameter thereof is the first pipe 1.
Less than 0. Next, each step until the first and second pipes 10 and 60 are relatively displaceably connected by the ball joint will be described.

First, a pipe expansion step is performed (FIG. 10B).
reference). Here, one end of the second pipe 60 is expanded by bulging, but since the second pipe 60 is hollow and does not have a partition plate for dividing the inside into two flow paths,
The tube is expanded without any problems. After this pipe expanding step, the second pipe 60 is moved to the large diameter portion 60 substantially matching the diameter of the first pipe 10.
a, a tapered portion 60b that gradually changes from the original diameter to the expanded diameter, and a small-diameter portion 60c that keeps the original diameter.

Subsequently, a partition plate attaching step is performed (FIG. 1).
0 (c)). Here, as shown in FIG. 12, the outer shell has a large diameter portion 60a and a tapered portion 60b of the second pipe after the diameter expansion.
And a second shape formed to match the shape of the small diameter portion 60c.
A partition plate 70 is used. At the end of the second partition plate 70 on the side corresponding to the width of the large-diameter portion 60a, there is provided a concave portion 71 formed so as to be accurately concave in an arc shape. In addition, the second partition plate 70 has flange portions 70a, 70a for welding and joining to the inner peripheral surface of the second pipe 60. In the partition plate attaching step, this second partition plate 70 is inserted into the expanded second pipe 60, and the flange portions 70a, 70
At a, it is welded to the inner peripheral surface of the pipe. As a result, the inside of the second pipe 60 is divided into two flow paths, and a concave portion 71 that is accurately concave in an arc shape is provided at an end thereof.

Subsequently, a connecting step is performed (see FIG. 11). Since this connection step is the same as in the first embodiment, the same components are denoted by the same reference numerals, and description thereof will be omitted. After this connection step, the end 1 bulging into an arc on the first pipe side.
2b and a concave portion 71 concaved in an arc shape on the second pipe side
Are arranged at a predetermined distance d, and are concentric arcs centered on a point Ce (see FIG. 11B, which is the center of the substantially hemispherical surface of the connecting flange 23). It is connected in the state where it was arranged.

Next, the operation of the connecting structure will be described. When this connection structure is adopted in an automobile, the first pipe 10 is arranged on the upstream side and the second pipe 60 is arranged on the downstream side, and the plate surfaces of the first and second partition plates 12 and 70 are substantially in the pipe axial direction. They are arranged so that the direction orthogonal to them substantially coincides with the vertical direction of the vehicle.

When vibration in the vertical direction of the vehicle is transmitted to this connection structure, the second pipe 60 on the downstream side vibrates in the vertical direction of the vehicle around the point Ce, that is, in the direction of the white arrow in FIG. 11B. I do. At this time, both the end 12b on the first pipe side and the concave portion 71 on the second pipe side are concentric arcs centered on the point Ce, and the second pipe 60 is located at the point C.
Since the displacement is centered on e, the concave portion 71 is displaced while maintaining a predetermined distance d from the arc-shaped bulging end portion 12b on the first pipe side. Therefore, even if they are relatively displaced, they do not come into contact with each other and do not largely separate from each other. This point is maintained even if the predetermined distance d is set small. Since the vibration at this time is attenuated and absorbed by the spring 2 and the like, the first pipe 1
No large vibration is transmitted from 0 to the second pipe 60.

In this embodiment, since the predetermined distance d can be set to be small, the exhaust gas passing through the flow paths S11 and S41 through the predetermined distance d and the flow paths S21 and S41
There is no possibility that the exhaust gases passing through 62 will interfere with each other. still,
Embodiments of the present invention are not limited to the above-described embodiments at all, and it goes without saying that various forms can be adopted as long as they belong to the technical scope of the present invention.

For example, in each of the above embodiments, the ball joint structure has been described as an example. However, any structure other than the ball joint structure may be used as long as it is a connecting structure that connects both pipes relatively displaceably. For example, a well-known pin joint structure may be adopted. FIG. 13 shows a case where a pin joint structure is employed in the first embodiment. In this pin joint structure, the upstream cover 91 and the downstream cover 92 are configured to be swingable about the pin 93, and are displaced in the vertical direction of the vehicle so that vibration in the same direction is effectively reduced by the cushioning material 94 or the like. Absorb. In this case, the end 12b bulging in an arc shape on the first pipe side and the second
The concave portion 31 concaved in an arc shape on the pipe side is arranged on a concentric circle centered on the pin 93. In this case, the same effect as in the above embodiment can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of flow dividing pipes having different diameters.

FIG. 2 is a process explanatory diagram showing each process up to connecting flow path split pipes of different diameters in the first embodiment;
(A) is a sectional view before a tube expanding step, (b) is a sectional view after a tube expanding step, and (c) is a sectional view after a covering step.

FIGS. 3A and 3B are explanatory views showing the connection structure of the first embodiment, wherein FIG. 3A is a sectional view and FIG. 3B is a sectional view taken along line AA.

FIG. 4 is a perspective view of a covering member of the first embodiment.

FIG. 5 is an explanatory diagram illustrating a modification of a variable portion of a second partition plate.

FIG. 6 is an explanatory diagram illustrating a modification of the variable portion of the second partition plate.

FIGS. 7A and 7B are process explanatory views showing each process up to the connection of different-diameter flow-path split pipes according to the second embodiment, wherein FIG. 7A is a cross-sectional view before a pipe-expanding step, and FIG. Sectional view,
(C) is a cross-sectional view after the covering step.

FIGS. 8A and 8B are explanatory views showing a connection structure according to a second embodiment, in which FIG. 8A is a sectional view and FIG. 8B is a sectional view taken along line BB.

FIG. 9 is a perspective view of a partition plate adapter according to a second embodiment.

FIGS. 10A and 10B are process explanatory views showing each process up to the connection of flow-path dividing pipes of different diameters according to the third embodiment, wherein FIG. 10A is a cross-sectional view before a pipe expanding step, and FIG. Sectional view,
(C) is a cross-sectional view after the covering step.

FIGS. 11A and 11B are explanatory views showing a connection structure according to a third embodiment, in which FIG. 11A is a cutaway view, and FIG. 11B is a CC sectional view.

FIG. 12 is a perspective view of a second partition plate of the third embodiment.

FIG. 13 is an explanatory diagram when a pin joint structure is employed in the first embodiment.

14A and 14B are explanatory diagrams of a conventional example, in which FIG. 14A is a sectional view and FIG. 14B is a sectional view taken along line DD.

[Explanation of symbols]

2 ... spring, 4 ... bolt, 4a ... spring presser,
6 ... Nut, 10 ... First pipe, 12 ... First partition, 12b ... End of first partition, 13,23
... Flange for connection, 14 ... Gasket, 20
..Second pipe, 22 ... second partition plate, 22c ...
Slit groove, 30... Coating member, 31.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G004 AA01 DA11 DA15 EA01 GA01 GA06 3H016 DA03 3H104 JA03 JB02 JC04 JC08 JD03 KB15 LA07 LA15 LA19 LF01 3J106 AB05 BA01 BB01 BC06 BC11 BD01 BE40 CA11 FA12

Claims (5)

[Claims] 1. A large-diameter first pipe whose inside is divided into two flow paths by a first partition plate formed so that an end swells in an arc shape, in a direction substantially orthogonal to an axial direction. A method of connecting a small-diameter second pipe whose inside is divided into two flow paths by a second partition plate provided at an end of an extensible variable portion so as to be relatively displaceable. A pipe expanding step of expanding the vicinity of the variable portion of the two pipes so as to substantially match the diameter of the first pipe; and a covering member having an arc-shaped concave portion formed so as to be concave in an arc shape in advance. A covering step of covering an end of a second partition of the pipe; and covering the end of the first pipe of the first pipe bulging in an arc shape and the end of a second partition of the second pipe. With the arcuate recess of the covering member arranged concentrically and at a predetermined distance, Method of connecting the flow path dividing pipe having different diameters, characterized in that the pipe comprises a connecting step for connecting to displace the shaft center of the concentric circle with respect to the first pipe. 2. The variable portion extends in a pipe axial direction.
2. The method according to claim 1, wherein the plurality of slit grooves are provided, and the covering member closes the slit grooves in the covering step. 3. 3. The covering member has a folded shape, and a back portion of the bent portion is formed into an arcuate concave portion. In the covering step, the second partition is provided in a folded space of the covering member. 3. The method according to claim 1, wherein an end of the plate is inserted. 4. A large-diameter first pipe whose inside is divided into two flow paths by a first partition plate whose end is formed to bulge in an arc shape, and a first pipe excluding a portion near one end of the pipe. A connection method for relatively displaceably connecting a small-diameter second pipe whose inside is divided into two flow paths by two partition plates, wherein a portion of the second pipe where the second partition plate does not exist Expanding the pipe to match the diameter of the first pipe; and the presence of the second partition in the second pipe after expanding the partition adapter formed in advance so that the end is concavely formed in an arc shape. An adapter mounting step of splitting this part into two flow paths by mounting it on a part that does not, and an arc-shaped bulging end of the first partition plate of the first pipe and the adapter of the partition plate of the second pipe. Concentric circles and ends A connecting step of connecting the second pipe so as to be displaced about the center of the concentric circle as an axis with respect to the first pipe in a state where the two pipes are arranged at a distance from each other. How to connect pipes. 5. A large-diameter first pipe whose inside is divided into two flow paths by a first partition plate whose end is formed to bulge in an arc shape, and a small-diameter second pipe whose inside is hollow. And a connecting step of connecting the end of the second pipe so as to be relatively displaceable, and expanding the end of the second pipe to match the diameter of the first pipe, so that the end is previously concave in an arc shape. A partition plate that divides the inside of the expanded second pipe into two flow paths by a second partition plate that is formed and whose outer shell is formed so as to substantially match the longitudinal sectional shape of the expanded second pipe. And an arc-shaped bulging end of the first partition plate of the first pipe and an arc-shaped concave end of the second partition plate of the second pipe are concentrically arranged at a predetermined distance. In this state, the second pipe is centered on the center of the concentric circle with respect to the first pipe. Method of connecting the flow path dividing pipe having different diameters, characterized in that it comprises a connection step of connecting to displace, the.