JPH0929329A - Production of metal tube body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely produce a metal body with a pair of dies and to greatly reduce a welding man-hours in a production method to produce a tube body made of metal. SOLUTION: The production consists of a process to form a half side pouring mouth 21a to a metal sheet 21, a process to overlap two sheets 21 to form a pouring mouth 23 a process to weld two sheets 21 to form a prebulged part 27 inside a welded part 25 and a process to hold two sheets 21 between a first die 29 and second die 31 forming recessed parts 29b, 31b. Further, the production consists of a bulging process to bulge the prebulged part 27 to the inner faces of recessed parts 29b, 31b while the first die 29 and second die 31 are pressed in the facing direction with a prescribed pressure and a liquid is poured in high pressure from the pouring mouth 23 and a process to cut the outside of welded part 25 of two sheets 21 and both ends of longitudinal direction of the tube body 35 bulged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal tube manufacturing method for manufacturing a metal tube.

[0002]

2. Description of the Related Art Generally, a metal pipe such as an exhaust pipe is manufactured by bending a linear metal pipe manufactured by a molding method such as roll molding into a predetermined shape.

However, in such a metal pipe, it becomes difficult to bend the metal pipe when the bending radius of the bent portion is small or when the thickness of the metal pipe is thin. Conventionally, as a method of manufacturing a metal pipe in such a case, for example, as shown in FIG. 8, a metal plate material is press-molded to form an upper plate 11 and a lower plate 13, and then the upper plate 11 and the lower plate 13 are formed. Edge 11 formed along the opening with the plate 13
A method is known in which a and 13a are brought into contact with each other and the edges 11a and 13a are welded.

As the joint pipe manufactured in this manner, the one disclosed in, for example, Japanese Utility Model Laid-Open No. 56-54210 is conventionally known.

[0005]

However, in such a conventional manufacturing method, since it is necessary to manufacture the upper plate 11 and the lower plate 13 by pressing, respectively, the upper plate 1
There is a problem that a set of press dies for one and a set of press dies for the lower plate 13 are required, and the cost of the die increases.

Further, since the upper plate 11 and the lower plate 13 already pressed into a three-dimensional shape are welded, there is a problem that the shape of the welded portion becomes complicated and a great number of welding steps are required. The present invention has been made to solve such a conventional problem, and a metal tube body can be easily and reliably manufactured by a set of molds, and the number of welding steps can be significantly reduced as compared with the conventional method. An object of the present invention is to provide a method for manufacturing a metal tube body that can be manufactured.

[0007]

According to a first aspect of the present invention, there is provided a method for manufacturing a metal pipe body, wherein a half side injection port is formed in a metal plate material, and the two side plates are opposed to each other. A step of forming a lap injection port, a step of continuously welding the two plate materials excluding the injection port to form a pre-bulging portion inside the weld, and manufacturing the two plate materials. A step of sandwiching between a first mold and a second mold in which a recess having a shape corresponding to the outer shape of the metal pipe body to be formed is formed; and the first mold and the second mold. A bulge step of forming a tubular body portion by injecting a liquid in a high pressure state from the inlet port while pressing in a direction opposite to each other with a predetermined pressure to form a tubular body portion, and A step of cutting the outside of the welded portion of the plate material and both ends in the axial direction of the bulged tube body portion.

According to a second aspect of the present invention, there is provided a method of manufacturing a metal tube body according to the first aspect, wherein in the step of forming a half-side inlet in the metal plate material, a three-dimensional processing for forming a rough shape of the metal tube body is performed. It is characterized by performing.

[0009]

In the method of manufacturing a metal pipe body according to claim 1, when the liquid is injected at a high pressure from the injection port while pressing the first mold and the second mold in a direction opposite to each other with a predetermined pressure, As the pre-bulging portion bulges, the two plate materials outside the pre-bulging portion sandwiched between the first die and the second die gradually slide in the direction of the concave portion to pre-bulge. The portion bulges to the inner surface of the recess to form the tubular body portion.

After that, the two plate materials having the tubular body portion are taken out from the mold, and the outside of the welded portion and both ends of the tubular body portion in the axial direction are cut to manufacture a metal tubular body.
In the method of manufacturing a metal pipe body according to claim 2, since the rough shape of the metal pipe body is formed when the half-side inlet is formed in the metal plate material, the first mold and the second mold are formed. It becomes possible to position the two plate materials having the pre-bulging portion with high accuracy between the two.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the method of the present invention will be described below with reference to the drawings. In one embodiment of the method for manufacturing a metal pipe body of the present invention, first, as shown in FIG. 1, a half-side inlet 21a is formed in a metal plate member 21.

The plate member 21 is made of, for example, stainless steel, aluminum or the like, and has a plate thickness of, for example, 0.5 mm. The half-side injection port 21a is formed in the center of one end of the plate member 21 by, for example, press working, and the opening has a semicircular shape. Next, as shown in FIG. 2, two plate members 21 are stacked so that the half-side inlets 21a face each other to form an inlet 23.

Thereafter, the two plate materials 21 are continuously welded except for the injection port 23, and the pre-bulging portion 27 is formed inside the welded portion 25. Here, the width W of the pre-bulging portion 27
Is half the total length of the metal tube to be manufactured. The welding is performed by, for example, laser welding, plasma welding, seam welding, or the like.

Next, as shown in FIG. 3, two plate materials 2 are used.
1 is sandwiched between a first mold 29 and a second mold 31, and a mating surface 29 of the first mold 29 and the second mold 31 is held.
It is transformed into the shape of a, 31a. The first mold 29 and the second mold 31 are provided with recesses 29b and 31b having a shape corresponding to the outer shape of the metal pipe body to be manufactured.

Further, injection port recesses 29c and 31c into which the injection port 23 is inserted are formed. Thereafter, as shown in FIG. 4, the injection port recesses 29c and 31c and the injection port 2 are formed.
The tip of the injection nozzle 33 is fitted and fixed to the nozzle 3. Then, next, the first mold 29 and the second mold 31 are pressed in a direction opposite to each other with a predetermined pressure, and in this state, the liquid is pressurized from the injection port 23 through the injection nozzle 33 to a high pressure. Then, the pre-bulging portion 27 is bulged to the inner surfaces of the recesses 29b and 31b to form the tubular body portion 35.

The pressing force of the first mold 29 and the second mold 31 in the opposite directions causes the pre-bulging portion 27 to swell when the liquid is injected from the inlet 23 at a high pressure. Accordingly, the two plate members 21 on the outer side of the pre-bulging portion 27 sandwiched between the first die 29 and the second die 31 are recessed 29.
The pressure is set so that it can gradually slide in the directions b and 31b.

Finally, as shown in FIG. 5, the two plate members 21 on which the tubular body portion 35 is formed are replaced by the first mold 29.
And the second metal mold 31, and as shown by the dotted line in the figure, the outside of the welded portion 25 and both ends of the tubular body portion 35 in the axial direction are cut, and the metal tubular body as shown in FIG. 37 is manufactured. The cutting is performed by laser processing, press processing, or the like.

In the above-described method for manufacturing a metal pipe body, the injection port 23 is formed by pressing a pair of molds, which are the first mold 29 and the second mold 31, in opposite directions with a predetermined pressure. Liquid is injected at high pressure from the pre-bulging portion 27 into the concave portion 29b,
Since the metal tube body 37 is formed by bulging up to the inner surface of 31b, the metal tube body 37 can be easily and reliably manufactured by one set of molds.

Therefore, the cost of the mold can be reduced. Further, since the welding is performed in a state where the two plate materials 21 are simply overlapped, the shape of the welded portion 25 is simplified and the welding can be performed easily and reliably. Further, in the above-described method for manufacturing the metal tube body, the width of the pre-bulging portion 27 is set to be half the total circumferential length of the metal tube body 37 to be manufactured. Therefore, the plastic deformation of the pre-bulging portion 27 is compared. Can be kept small,
It is possible to obtain the metal tube 37 having high strength.

Further, since the metal tube body 37 is formed by bulging the pre-bulging portion 27 by bulging, the pre-bulging portion 27 is not compressed unlike the case of press working. Wrinkles can be eliminated.

With the above-described method for manufacturing a metal pipe body, it is possible to easily and reliably manufacture a metal pipe having a bent portion with a small bending radius or a thin wall thickness. In addition, in the above-described embodiment, the example in which only the half-side inlet 21a is formed in the plate member 21 by the press working is described.
For example, as shown in FIG. 7, a rough shape of the metal tube body 37 may be formed when the half-side injection port 21a is formed.

By doing so, the first die 2
It becomes possible to position the two plate members 21 having the pre-bulging portions 27 formed between the 9 and the second mold 31 with high accuracy, and the pre-bulging portions 27 are formed in the concave portions 29b and 31b. The inner surface can be surely swollen with high accuracy. In addition, although the example which manufactured the cylindrical metal pipe body 37 was demonstrated in the above-mentioned Example, this invention is not limited to such an Example, For example, a metal pipe with a rectangular cross section, a triangular shape, etc. The body can also be easily manufactured.

[0023]

As described above, in the method of manufacturing a metal tube body according to the first aspect of the present invention, a set of dies including a first die and a second die are opposed to each other at a predetermined pressure. Since the metal tube is formed by injecting the liquid at a high pressure from the injection port while pressing in the direction and bulging the pre-bulging portion to the inner surface of the recess, the metal tube can be easily formed by a set of molds. It can be reliably manufactured.

Therefore, the cost of the mold can be reduced. Further, since the welding is performed in a state where the two plate materials are simply overlapped, the shape of the welded portion is simplified and the welding can be performed easily and reliably. In the method of manufacturing a metal pipe body according to claim 2, since the rough shape of the metal pipe body is formed when the half-side inlet is formed in the metal plate material, the first mold and the second mold are formed. It is possible to position the two plate materials having the pre-bulging portion with high accuracy between the two, and it is possible to surely bulge the pre-bulging portion to the inner surface of the recess.

[Brief description of drawings]

FIG. 1 is a perspective view showing a step of forming a half-side injection port in a metal plate material in an embodiment of a method for manufacturing a metal tube body of the present invention.

FIG. 2 is a perspective view showing a step of forming an injection port and a step of forming a pre-bulging portion by welding in one embodiment of the present invention.

FIG. 3 is a perspective view showing a step of sandwiching two plate materials between a first mold and a second mold in one embodiment of the present invention.

FIG. 4 is a perspective view showing a bulge process in one embodiment of the present invention.

FIG. 5 is a perspective view showing a cutting step in one embodiment of the present invention.

FIG. 6 is a perspective view showing a metal tube body manufactured according to an embodiment of the present invention.

FIG. 7 is a perspective view showing a state in which a rough shape of a metal tube body is formed in a step of forming a half-side injection port in a metal plate material.

FIG. 8 is a perspective view showing a conventional method for manufacturing a metal tube body.

[Explanation of symbols]

 21 plate material 21a half-side injection port 23 injection port 25 welded part 27 pre-bulging part 29 first mold 29b recessed part 31 second mold 31b recessed part 37 metal tube

Claims (2)

[Claims] 1. A half-side inlet (2) is attached to a metal plate (21).
1a), a step of forming the overlapping injection port (23) so that the half-side injection ports (21a) face each other of the two plate materials (21), and the two plate materials (21) Except for the injection port (23), the welding is continuously performed and the pre-bulging portion (2) is formed inside the welding portion (25).
7), and a metal tube body (37) for manufacturing the two plate materials (21)
Sandwiching between a first mold (29) and a second mold (31) in which recesses (29b, 31b) having a shape corresponding to the outer shape of the first mold (29) are formed. 29) and the second die (31) are pressed in a direction opposite to each other with a predetermined pressure, and the injection port (2
Liquid is injected under high pressure from 3) and the pre-bulging part (2
7) Bulge step of bulging the inner surface of the recesses (29b, 31b) to form the tubular body portion (35), and the bulge outside the welded portion (25) of the two plate members (21) and And a step of cutting both ends of the tubular body portion (35) in the axial direction, the method for producing a metal tubular body. 2. The method for manufacturing a metal pipe body according to claim 1, wherein in the step of forming the half-side inlet (21a) in the metal plate material (21), the metal pipe body (37) is roughly formed. A method of manufacturing a metal tube body, which comprises performing three-dimensional processing for forming a shape.