JP2000170964A - Coupling method for pipe body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To couple a pipe body with a diameter change or bending in the vicinity of a tip part to be coupled without welding. SOLUTION: A tip part 16a of a flange 10 and a tip part 20a of a pipe 20 are inserted into an inserting part 40a and an inserting part 40b, respectively, force is capplied from the inside of an adapter 30, a small diameter part 36 becomes a large diameter and the diameter part 36 is swollen and deformed so as to be smaller as the diameter goes closer to both end part sides and also the tip parts 16a, 20a are swollen and deformed to the outside. By swelling and deformation, the tip part 16a and the tip part 20a are flared and the tip parts 16a, 20a are in close connection with an inner pipe 32 and large diameter parts 38a, 38b. As a result, a neck part 16 and the pipe 20 are surely and strongly coupled via the adapter 30. Because force is applied from the inside of the adapter 30, the outer peripheries of the neck part 16 and the pipe 20 are not required to be held by hardware and can be coupled, even if a diameter change such as a bowl-shaped part 14 exists near the tip part 16a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of connecting tubes.

[0002]

2. Description of the Related Art In an exhaust pipe of an internal combustion engine, for example, a tubular neck portion of a flange and a pipe are connected by welding. In some cases, welding is also used to join the pipes. However, the joining by welding as described above has a problem that the time required for welding all around is long, it is difficult to obtain a smooth welding line, and stress concentration tends to occur.

[0003] Such problems associated with welding do not occur if pipes are joined together without using welding, and such techniques are disclosed in Japanese Patent Application Laid-Open Nos. 4-54393 and 4-266684. There is something. In these techniques, a joining jig is used in which a thick portion is provided symmetrically in a central portion inside a short metal tube, and a groove that opens in the axial direction is formed in the thick portion. In order to join the pipes using this joining jig, the outer ends of the two pipes and the joining jig to be joined by the die of the press machine are held, and the pipe ends of the pipes are respectively joined to the joining jig. While pressing the joint jig from the left and right into the groove, also press the joining jig against the center.
Then, the center part of the joining jig is projected and deformed outward,
The pipe end fitted in the groove is expanded in a flange shape and caulked in the groove, whereby the two pipes are joined to each other.

According to the techniques disclosed in JP-A-4-54393 and JP-A-4-266684, the pipes are connected to each other without using welding, so that there is no problem associated with welding.

[0005]

However, the technology disclosed in JP-A-4-54393 and JP-A-4-266684 has a structure in which the outer periphery of a pipe and a joining jig is held by a die of a press machine. Therefore, it is necessary to form a straight pipe from the pipe end to a certain extent (more than the thickness of the mold). Therefore, this method cannot be applied to the case where there is a bending or a change in diameter (expansion or drawing) near the pipe end (for example, when a neck portion of a flange is connected to a pipe). That is, welding had to be adopted for joining such pipes.

According to the present invention, in connecting a flange to a pipe or pipes without welding, even if the pipe has a bend or a change in diameter near the pipe end, the pipe can be connected. It is intended to provide a way.

[0007]

According to a first aspect of the present invention, there is provided a method of connecting a tubular body, wherein an inner pipe and a small-diameter portion fixed to an outer periphery of the inner pipe are provided at a central portion in a longitudinal direction. A large-diameter portion forming an insertion portion into which an end of the tubular body can be inserted between the small-diameter portion and an outer tube provided on both sides of the small-diameter portion. It is a method of joining together, wherein the end of one tube is inserted into one of the insertion portions, the end of the other tube is inserted into the other of the insertion portions, and then from the inside of the adapter. By applying force, the adapter bulges outward so that the center portion of the adapter becomes larger in diameter and becomes smaller toward both ends, and the ends of the two tubes also bulge outward. It is characterized by being deformed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pipe to which the method for connecting pipes according to claim 1 is applied is not limited to a pipe, but also includes a tubular member such as a neck portion of a flange. Therefore, this connection method can be applied to connection between pipes, connection between pipes and flanges (neck portions), connection between flanges, and the like.

In this connection method, the adapter used for connecting the pipes has a double pipe structure comprising an inner pipe and an outer pipe which are connected to each other. A small-diameter portion fixed to the outer periphery of the inner tube is provided, and a large-diameter portion is provided on both sides of the small-diameter portion to form an insertion portion into which the end of the tube can be inserted between the small-diameter portion and the inner tube. . The inner tube and the outer tube are connected by, for example, spot welding performed on a small diameter portion, but another method may be used.

[0010] In the insertion portion formed by the inner tube and the large diameter portion,
Since the end of the pipe to be joined is inserted, the outer diameter of the inner pipe is smaller than the inner diameter of the pipe to be joined, and the inner diameter of the large diameter part is the outer diameter of the pipe to be joined. Larger than the diameter. However, since it is not preferable that the end of the tube inserted into the insertion portion rattles, the clearance between the end of the tube and the insertion portion should be as small as possible.

To connect the tubes, first, the end of one tube is inserted into one insertion portion of the adapter, and the end of the other tube is inserted into the other insertion portion. Then, a force is applied from the inside of the adapter, so that the center portion of the adapter has a large diameter and the diameter decreases toward both ends,
The adapter is swelled outward and the ends of both tubes inserted into the insertion portion are swelled outward.

In order to apply a force from the inside of the adapter, an expanding device such as a split bulge may be used. By swelling the adapter into such a shape and swelling the ends of both tubes outward, the ends of both tubes are brought into close contact with the inner tube and the large diameter portion. For this reason, the large-diameter portion becomes resistant to the force in the direction in which the tube is pulled out of the adapter, and the inner tube becomes resistant to the force in the direction in which the tube is pushed into the adapter. The tubes are connected and the tubes are connected via an adapter.

Moreover, since the end of the tube is in close contact with the outer surface of the inner tube and the inner surface of the large-diameter portion, airtightness at the connection portion is ensured.

[0014]

Next, embodiments of the present invention will be described more specifically by describing examples of the present invention. This embodiment is an example in which a flange 10 and a pipe 20 are connected via an adapter 30 as shown in FIG.

The flange 10 has a flange face 12 which is brought into contact with a counterpart (not shown) and is tightened with a bolt or the like.
There is provided a bowl-shaped portion 14 connected to this and a neck portion 16 corresponding to one of the tubular bodies. The pipe 20 corresponding to the other pipe is a straight pipe. The adapter 30 has a double pipe structure including an inner pipe 32 and an outer pipe 34. The inner pipe 32 is a short straight pipe, while the outer pipe 34 is a constricted pipe provided with a small-diameter portion 36 at the center in the longitudinal direction and large-diameter portions 38a and 38b on both sides thereof. In this embodiment, the inner tube 3
Although the length of the outer tube 34 is the same as that of the outer tube 34, they may be different.

The small diameter portion 36 has an inner diameter matching the outer diameter of the inner tube 32, is fitted to the inner tube 32, and is fixed to the inner tube 32 by four spot weldings performed at intervals of about 90 degrees in the circumferential direction. Have been. A large-diameter portion 38a continuously provided on both sides of the small-diameter portion 36,
38b is formed between the outer periphery of the inner tube 32 and insertion portions 40a and 40b into which the end 16a of the neck portion 16 and the end 20a of the pipe 20 can be inserted.

In this embodiment, the wall thicknesses of the neck portion 16 and the pipe 20 are equal to each other, but need not be equal.
Also, the width of the insertion portions 40a, 40b (the distance between the outer periphery of the inner tube 32 and the large-diameter portions 38a, 38b) slightly exceeds the wall thickness of the neck portion 16 and the pipe 20 (substantially the same), The ends 16a, 20a do not rattle in the inserts 40a, 40b.

The flange 10 and the pipe 2 are connected by the adapter 30.
0, first, as shown in FIG.
a, insert the end 16a of the neck portion 16 into the insertion portion 40b.
Is inserted into the end 20a of the pipe 20. Then, a force is applied from the inside of the adapter 30 so that the central portion (small diameter portion 36) of the adapter 30 has a large diameter as shown in FIG.
0 is swelled and deformed outward, and the end 1 of the neck 16 is
6a and the end 20a of the pipe 20 also bulge outward and deform.

Although there is no limitation on the method of the bulging deformation, it is convenient to use a split bulge 50 as shown in FIG. 4, for example. The split mold bulge 50 has a form in which four split molds 52 are assembled. Each split mold 52 has the same shape as each other, and corresponds to one piece obtained by dividing a tubular body corresponding to the split bulge 50 into four pieces. An inner taper surface 54 is provided on the inner surface of the split mold 52, and the taper direction of the split taper
This is a direction in which the distance between the inner tapered surfaces 54 facing each other decreases from the sixth side toward the front end side. Also, each split mold 52
Is provided with a convex portion 58 having a mountain-like cross section.

In the split type bulge 50 having such a structure, when a push rod (not shown) having a tapered surface matching with the inner tapered surface 54 is pushed in from the split flange 56 side, the split die 52 is moved with the advance of the push rod. The distance between them increases. In order to perform the above-mentioned bulging deformation processing with such a split mold bulge 50, first, as shown by a chain line in FIG.
2 are brought into contact with each other in a contracted state, and inserted into the adapter 30 in the state shown in FIG. At this time, the convex portion 58 is made to correspond to the small diameter portion 36 of the adapter 30. After the positioning of the adapter 30 and the split bulge 50 (correspondence of the convex portion 58 and the small diameter portion 36) is completed, the split bulge 5
When the push rod is pushed into the inside of the cylinder, the split die 5
Since the distance between the two is increased, each convex portion 58 is
A portion corresponding to the small diameter portion 36 of 0 is pressed from the inside to the outside, and this portion is swelled and deformed outward. As a result, the adapter 30, the end 16a of the neck 16 and the end 20a of the pipe 20 bulge and deform as shown in FIG. Thereafter, the push rod is withdrawn to make the split bulge 50 in a contracted state, and if this is withdrawn from the adapter 30,
The bulging process is completed.

By this bulging process, as shown in FIG. 3, the end 16a of the neck 16 and the end 20a of the pipe 20 are formed.
Is expanded in a trumpet shape on the outer peripheral side, the end 16a of the neck portion 16 is brought into close contact with the inner tube 32 and the large-diameter portion 38a, and the end 20a of the pipe 20 is connected to the inner tube 32 and the large-diameter portion 38b. Be brought close together.

For this reason, the flange 10 (neck portion 16)
The large-diameter portion 38a has a resistance against the force in the direction in which the neck portion 16 is pulled out from the adapter 30, and the inner tube 32 has a resistance against the force in the direction of pushing the neck portion 16 into the adapter 30.
The neck portion 16 and the adapter 30 are securely connected. Similarly, the large-diameter portion 38b resists the force in the direction in which the pipe 20 is pulled out from the adapter 30 and the inner tube 32 resists the force in the direction in which the pipe 20 is pushed into the adapter 30. And the adapter 30 are securely connected. In this way, the flange 10 (the neck 1
6) and the pipe 20 are securely and firmly connected via the adapter 30.

Further, since the end portions 16a and 20a are in close contact with the outer surface of the inner tube 32 and the inner surfaces of the large-diameter portions 38a and 38b, airtightness at the connection portion is also ensured. As described above, the embodiments of the present invention have been described according to the examples. However, it is needless to say that the present invention is not limited to such examples, and can be variously implemented without departing from the gist of the present invention.

[0024]

As described above, according to the method of joining tubes according to the present invention, the ends of the adapter and the tube are expanded and deformed.
Since the pipes are connected via the adapter, the time required for the connection work is practically only the time required for the bulging deformation,
It is possible to reduce the work time and the number of work steps.

Further, the appearance of the joint portion is good, and since heat treatment such as welding is not performed, stress concentration due to thermal stress does not occur. Moreover, sufficient airtightness can be secured. Further, when the ends of the adapter and the tube are swelled and deformed, an external force is applied from the inside to the outside of the adapter. Therefore, it is not necessary to hold the outer periphery of the tube or the adapter with a mold or the like. Even if there is a bend or a change in the diameter near one or both of the pipe ends, the pipes can be connected to each other regardless of such a bend or a change in the diameter. In particular, it is suitable for connecting a pipe or the like having a bend near the neck or end of the flange.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state where axes of a flange, an adapter, and a pipe of an embodiment are aligned.

FIG. 2 is a cross-sectional view showing a state where a neck portion of a flange and an end portion of a pipe according to the embodiment are inserted into an adapter.

FIG. 3 is a cross-sectional view showing a state where the flange and the pipe are connected by the adapter of the embodiment.

FIG. 4 is an explanatory view of a split bulge used in the embodiment, FIG. 4 (a) is a side view of a split flange side, FIG. 4 (b) is a sectional view taken along line AA of FIG. 4 (a), FIG. 4C shows FIG. 4B.
FIG. 7 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Flange, 12 ... Flange face, 14 ... Bowl-shaped part, 16 ... Neck part (tube), 16a ... End, 20 ... Pipe (tube), 20a ... End, 30 ... Adapter, 32 ...
Inner tube, 34 ... Outer tube, 36 ... Small diameter portion, 38a ... Large diameter portion, 3
8b: large diameter portion, 40a: insertion portion, 40b: insertion portion, 50
... Split bulge, 52 ... Split, 58 ... Protrusion.

Claims (1)

[Claims] 1. An inner tube and a small-diameter portion fixed to an outer periphery of the inner tube are provided at a central portion in a longitudinal direction, and an insertion portion through which an end of a tube body can be inserted is formed between the inner tube and the inner tube. A method of connecting pipes to each other via an adapter consisting of an outer pipe provided on both sides of the small-diameter section, wherein the large-diameter section is connected to one end of one pipe body at one of the insertion portions. After inserting the end of the other tubular body into the other of the insertion portions, a force is applied from the inside of the adapter, and the diameter of the adapter becomes larger as the center portion becomes larger in diameter and becomes closer to both ends. A method for joining pipes, wherein the adapter is swelled outward so as to reduce the size, and ends of the two pipes are swelled outward.