JP2003205337A - Local thickening method and device for metallic tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently forming in a short time a thick tube wall bulged out in one or both of the inner and outer surface in a desired area in the axial direction of a metallic tube. <P>SOLUTION: A metallic tube 1 is heated in a desired area in the axial direction of the tube; and on the inner and outer surfaces of the heated area, an inner and outer surface dies 5, 8 are attached which are equipped with an opening 9 over the entire circumference of the tube at the position where the wall is to be bulged out, and which are equipped with control faces 5a, 8a for regulating the inner and outer surfaces so as not to be bulged out at other positions. Then, a compression force is applied from both ends of the metallic tube 1 so that nearly the center of the opening 9 becomes the center axis of the plastic working, thereby pushing the tube wall into the opening 9 to form the thick part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a thickened portion by bulging a pipe wall on one or both of an inner surface and an outer surface in a partial region of a metal pipe such as a rectangular steel pipe or a round steel pipe in the pipe axial direction. Method and device.

[0002]

2. Description of the Related Art Conventionally, as a pillar material used for building structures,
Metal pipes such as square steel pipes and round steel pipes are used. When this metal pipe is used as a pillar material, in order to join a beam material such as H-section steel to the pillar material, a joint member for beam joining is fixed to the end of the pillar material by welding or the like. Beam members are generally welded or joined to the connection members with bolts or the like. However, when the connection member is used, the number of parts used increases, the number of joints increases, and the number of work steps and work time increase, resulting in high cost.

Therefore, in order to make it possible to use one metal pipe as a through pillar extending over a plurality of floors,
A column member has been proposed in which a region serving as a joint for joining beam members is partially thickened to form a thickened portion (see, for example, JP-A-8-120775). In the pillar material proposed in this publication, since the thickened portion has the strength and thickness necessary for joining the beam materials, the thickened portion can be used as a joint portion for joining the beam materials, and the integrated structure It has an advantage that the metal tube of can be used as a through column.

However, there are some points to be further improved in this pillar material. That is, in the pillar material of this configuration, since the entire region used as the connecting portion is the thickened portion, the length of the thickened portion is 1.3 to 1.5 times that of the beam and the thickness is not significant. Since it is necessary to make the thickness of the pipe 2 to 3 times the thickness t, the thickening region is long and the amount of thickening is large. In addition, since the pipe length is shortened by the thickening process, there is a problem that a bare pipe that is considerably longer than the length of the pillar material to be manufactured is required.

Therefore, the inventors of the present invention have made the metal wall used as a pillar material bulge on the outer surface and / or the inner surface only in a narrow region including the position where the flange portion of the beam material is brought into contact with the metal wall, and the strength is increased. Considering a structure in which a beam member is joined to the thickened portion with a large thickened portion. However, in the case of adopting this structure, it is desirable that the wall thickness of the thickened portion is 2.5 to 4 times the thickness of the raw pipe in order to secure necessary strength in the thickened portion. A method and apparatus for efficiently forming the thickened portion in a short time have not been developed.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and an increase in the thickness of a metal tube is caused to bulge on one or both of the inner surface and the outer surface in a partial area of the metal tube in the tube axial direction. An object of the present invention is to provide a method and an apparatus capable of efficiently forming a thick portion in a short time.

[0007]

The method of the present invention, which has been made to solve the above-mentioned problems, has the following advantages:
In forming the thickened portion by bulging the pipe wall on one or both of the inner surface and the outer surface, first, the region of the metal tube to be plastically deformed to form the thickened portion is heated, and then the heated region is heated. Each of the inner and outer surfaces of the metal pipe is provided with an opening around the entire circumference of the pipe at the position where the pipe meat should be expanded, and at other positions, there are restriction faces for restricting the expansion of the pipe inner surface and the pipe outer surface. The inner surface mold and the outer surface mold are mounted, and then the metal tube is relatively pushed into the mold from both sides of the part where the mold is mounted, whereby the tube of the metal tube in the heated region. The meat is plastically flown into the opening from both sides to upset the thickened portion. With this configuration, with the inner and outer surfaces of the heated region of the metal pipe being regulated by the mold, the metal pipe is pushed into the mold at once, and the pipe meat is plastically flowed into the opening of the mold to increase the thickened portion. Upset formation is possible, and the thickened portion can be formed in a short time. Further, by causing the pipe meat to plastically flow into the opening from both sides of the mold, a flow of the pipe meat into the opening is stably generated, and the thickness is about 2.5 to 4 times the thickness of the raw pipe. The thickened portion can be formed easily and promptly.

Further, the device of the present invention used for carrying out the above method is a heating device which is arranged so as to be movable in a desired region in the axial direction of a metal pipe arranged at a predetermined position, and which heats the desired region of the metal pipe. , The inner surface and the outer surface of the heated region of the metal pipe are respectively provided with openings over the entire circumference of the pipe at the position where the pipe meat is to be expanded, and the pipe inner surface and the pipe outer surface are not expanded at other positions. A configuration in which an inner surface die and an outer surface die having a restriction surface that regulates as described above, and a pushing device that relatively pushes the metal tube into the die from both sides of the portion on which the die is attached, It was done. With this configuration, the metal pipe to form the thickened portion is arranged at a predetermined position, the desired region in the pipe axial direction is heated by the heating device, and then the heating device is evacuated to an appropriate position. Attach the inner and outer molds to the inner and outer surfaces of the heated area of
In that state, the metal tube of the heated region is pushed into the mold from both sides of the part where the mold is attached by the pushing device, so that the metal meat of the heated region is inserted into the opening of the mold. The thickened portion can be upset by plastically flowing in from the above, and the method of the present invention can be carried out.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The metal pipe for which the thickened portion is formed by the method and apparatus of the present invention is arbitrary as long as it can be hot plastically worked. Typical examples are a square steel pipe and a round steel pipe. Can be mentioned. The shape of the thickened portion is also arbitrary, and may be a shape in which the tube meat is bulged only on the outer surface side of the tube, a shape that is bulged only on the inner surface side of the tube, or a shape that is bulged on both the inner and outer surfaces of the tube. The thickened portion is mainly used for beam connection when a metal tube is used as a pillar material, but may be used for other purposes.

Among the molds used in the present invention, the mold arranged on the side where the tube meat is expanded has an opening for allowing the tube meat to expand, but the structure has various forms. Can be taken. In one embodiment, this mold is configured by arranging mold elements having an integral structure in the tube axis direction, and a tube having a width equal to the dimension of the thickened portion in the tube axis direction provided in the mold element. The opening is constituted by a circumferential groove. In this embodiment, there is an advantage that the width of the thickened portion can be set to a predetermined thickness determined by the groove width regardless of the accuracy of the mounting position of the mold.

Further, in another embodiment, the mold disposed on the side where the tube meat is bulged is configured by disposing mold elements having a two-body structure in the tube axis direction, and the two mold elements are arranged. The constituent members of the body are arranged with a gap in the pipe axis direction, and the opening is formed with the gap. In this embodiment, there is an advantage that the mold can be configured by a mold element having a simple structure, and that the width of the thickened portion can be easily changed by changing the interval between the two component members. .

It is preferable that the inner surface die arranged on the inner surface side of the metal tube has a structure capable of expanding and contracting. With this configuration, the inner die can be easily attached to and detached from the metal tube.

The present invention will be described in more detail below with reference to the embodiments shown in the drawings. FIG. 1 is a schematic perspective view showing a schematic configuration of a local thickening device according to an embodiment of the present invention.
Reference numeral 1 denotes a metal pipe to be locally thickened, and in this embodiment, a rectangular pipe such as a rectangular steel pipe is used. In addition,
The target metal pipe is not limited to a rectangular pipe, but may be a circular pipe such as a round steel pipe. The metal tube 1 is held at a predetermined position by a suitable supporting means (not shown) such as a supporting roll. A heating device 2 heats a desired region of the metal tube 1. In this embodiment, an induction coil that heats the metal tube by induction heating is used. Reference numeral 3 is a supporting device that supports the heating device 2. This supporting device 3 is held by a moving means (not shown) so as to move in parallel to the metal tube 1, and with this structure, the heating device 2 moves to a desired area along the metal tube 1. It is possible to heat the metal tube, and after the heating is completed, it is possible to evacuate from the heating area.

Reference numeral 5 denotes an inner surface die (core) arranged on the inner surface of the region of the metal tube 1 to be subjected to the thickening process, and 6 is a support shaft for supporting the inner surface die 5. A moving means (not shown) for moving the support shaft 6 in the axial direction is connected to the support shaft 6, and the inner surface die 5 is positioned at a desired position in the pipe axis direction of the metal tube 1 by the moving means. This is a possible configuration. As shown in FIG. 2, the inner surface die 5 used in this embodiment is provided with a rectangular cylindrical regulation surface 5a that regulates the entire inner surface of the region of the metal tube 1 to be thickened so as not to bulge inward. ing. The inner surface mold 5 preferably has a structure capable of expansion / contraction, but may have a structure incapable of expansion / contraction. In that case, in order to facilitate extraction from the pipe, the restriction surface 5a
It is preferable to have a small taper.

In FIG. 1 and FIG. 2, reference numeral 8 denotes an outer surface mold which is arranged on the outer surface of the region of the metal tube 1 to which the thickening process is applied. The outer surface mold 8 has a split structure composed of two mold elements in a direction orthogonal to the tube axis so as to facilitate mounting on the outer surface of the metal tube 1. The outer surface mold 8 used in this embodiment allows the tube meat to bulge toward the outer surface of the tube at a predetermined position, and sets the width of the thickened portion formed by the bulging (the tube axial direction dimension) to a predetermined dimension. For the purpose of regulation, the regulation surface 8a is provided with an opening 9 extending over the entire circumference of the pipe at a position where the pipe meat is to be expanded, and is regulated so that the outer surface of the pipe is not expanded at other positions.
Is equipped with. More specifically, the two mold elements forming the outer surface mold 8 are integrally formed in the tube axis direction, and the dimension of the thickened portion in the tube axis direction is provided in the mold element. The opening 9 is formed by a groove in the circumferential direction of the pipe having a width equal to that of the opening 9, and the inner surfaces on both sides of the opening 9 serve as the restriction surface 8a. The depth of the groove forming the opening 9 is larger than the protruding height of the thickened portion to be formed from the outer surface of the tube. The outer surface mold 8 is held on a moving table (not shown) that moves along the metal tube 1,
It is configured so that it can be moved to a desired position in the tube axis direction of the metal tube 1.

Reference numeral 11 denotes a pushing device which pushes the metal tube 1 relatively into the die 8 from both sides of the portion where the die 8 is mounted. In this embodiment, both ends of the metal tube 1 are supported. And a pair of pipe support members 12A and 12B that are movable in the pipe axis direction, and hydraulic cylinders 13A and 13B that move the pipe support members 12A and 12B to push the metal pipe 1 in the pipe axis direction. . This hydraulic cylinder 13
A and 13B are provided with control means for controlling the amounts of pushing the metal pipe 1 through the pair of pipe support members 12A and 12B so as to be equal to each other.

Next, the thickening operation by the apparatus having the above construction will be described. The metal tube 1 is set as shown in FIG. 1, and both ends are supported by the pair of tube support members 12A and 12B. Next, the heating device 2 is moved to a position where the thickened portion of the metal tube 1 is to be formed, and the region to be plastically deformed for forming the thickened portion is heated to a temperature at which plastic deformation is easy (for example, a red heat state). Then, after heating, it is retracted to a position that does not interfere with the thickening process.
Then, the inner die 5 and the outer die 8 are placed inside the heating region,
Attach to each outside. The state at this time is the state shown in FIG. 2A, and the region 15 shown by hatching of the metal tube 1 is shown.
Is the heating area. Next, the pushing device 11 is operated to push the metal tube 1 from both ends toward the heating region 15 with the hydraulic cylinders 13A and 13B. At this time, the pushing amounts from both ends of the metal tube 1 are set to be substantially equal. As a result, the metal pipe 1 is pushed into the mold from both sides of the molds 5 and 8, and the metal wall of the heating region 15 plastically flows into the opening 9 from both sides of the opening 9, and Since the pushing amounts from both ends of 1 are substantially equal to each other, the center of the opening 9 becomes the center of plastic deformation, and the pipe wall bulges into the opening 9 quickly and stably. Thus, as shown in FIG. 2B, the thickened portion 1a having the desired outer diameter is upset in the opening 9. Here, even when the thickened portion 1a having the desired outer diameter is formed in the opening 9, the thickened portion 1a is in contact with both side surfaces 9a of the opening 9 only at a part of both sides, and most of the thickened portion 1a is covered with the outer surface metal. Since it is not in contact with the mold 8, it is less likely that it will be rapidly cooled and hardened by coming into contact with the outer surface metal mold 8 during the expansion of the tube meat. From this point as well, the tube meat can be quickly and stably opened. It swells inside. Thus, as shown in FIG. 2 (c),
The thickened portion 1a having a thickness T of 2.5 to 4 times the tube thickness t and a width W (length in the tube axis direction) of 3 to 10 times the tube thickness t is 1
It can be formed by a heating or pressing operation once or a plurality of times (the mold may be changed in a plurality of times). After forming the thickened portion 1a in the opening 9, after the thickened portion 1a is appropriately cooled,
The inner mold 5 and the outer mold 8 are removed. As described above, the thickened portion 1a having the shape shown in FIG. 2C is formed. After that, by repeating the above operation for one metal pipe 1, the thickened portion 1 is successively formed at a plurality of positions in the pipe axial direction of the metal pipe 1.
a can be formed.

The thickened portion 1a formed as described above can be used as a connecting portion for connecting beam members. Further, the thickened portion 1a can be formed at a desired position and in a desired number. Therefore, by the local thickening device, the metal pipe having a thickened portion formed at a desired position in the pipe axis direction is used as a pillar material at various places, for example, as a through pillar extending over a plurality of floors.
It can be preferably used. In addition, since the width of the thickened portion 1a can be reduced, the width of the thickened portion 1a can be reduced to the minimum width (for example, H
When connecting a beam made of shaped steel, the width can be set so that only the flange part can be supported, and this makes it possible to reduce the unit metric weight of the column made of metal pipe to a small value. The work of transporting and assembling pillars can be facilitated.

In the above embodiment, the thickened portion 1a bulging only on the outer surface side of the tube is formed on the metal tube 1. However, the shapes of the inner surface mold 5 and the outer surface mold 8 may be changed. Can form thickened portions of various shapes. Also, the shape of the mold,
The structure can be variously changed. Some examples are shown below. In the embodiment shown in FIG. 3, the inner surface mold 5A is provided with an opening 20 formed in the center by a groove provided over the entire circumference in the pipe circumferential direction and the inner surface of the pipe is not bulged inward on both sides thereof. The regulation surface 5a for regulating is provided, and the outer surface die 8A is provided with the regulation surface 8a for regulating so that the entire outer surface of the region of the metal tube 1 to which the thickening process is performed does not bulge outward. By performing thickening processing using these molds 5A and 8A, as shown in FIGS. 3 (b) and 3 (c),
It is possible to form the thickened portion 1b that bulges only on the inner surface side of the pipe. The inner die 5A used here has a structure that can be reduced in diameter or disassembled for removal after the thickening process.

In the embodiment shown in FIG. 4, the inner surface mold 5B is used.
Is provided with an opening 22 formed by a groove having a shallow trapezoidal cross section, which is provided in the center in the pipe circumferential direction over the entire circumference, and regulates the pipe inner surface on both sides thereof so as not to bulge inward.
The outer surface die 8B is provided with an opening 23 formed in the center by a deep groove provided over the entire circumference in the tube circumferential direction, and the outer surface of the die is restricted so that the outer surface of the tube does not bulge outward. The regulation surface 8a is provided. The depth of the groove (opening) 23 formed in the outer surface mold 8B is set larger than the protruding height of the bulging portion formed in the metal tube 1 from the outer surface of the tube. By performing thickening using these molds 5B and 8B, as shown in FIGS. 4 (b) and 4 (c), a bulging portion having a shape corresponding to the cross-sectional shape of the opening 22 is formed on the inner surface of the pipe. 1ca
Is formed, and a bulging portion 1cb having a width equal to the width of the opening 23 is formed on the outer surface side of the pipe, and the thickened portion 1c having a bulging shape inside and outside the pipe can be formed.

In the embodiment shown in FIG. 5, the inner surface mold 5C is used.
Is provided with a restriction surface 5a for restricting the inner surface of the pipe from bulging inward on both sides thereof, with an opening 25 formed by a deep groove provided in the center along the entire circumference in the pipe circumferential direction, The outer die 8C is provided with an opening 26 formed in the center in the circumferential direction of the pipe over the entire circumference and formed with a groove having a shallow trapezoidal cross section, and is regulated so as not to bulge the outer surface of the pipe on both sides thereof. The structure is provided with the surface 8a. The depth of the groove (opening) 25 formed in the inner surface mold 5C is set larger than the protruding height of the bulging portion formed in the metal tube 1 from the inner surface of the tube. By performing thickening using these molds 5C and 8C, as shown in FIGS. 5B and 5C, a bulging portion having a shape that matches the cross-sectional shape of the opening 26 on the outer surface of the pipe. 1 da
Is formed, a bulging portion 1db having a width equal to the width of the opening 25 is formed on the inner surface side of the pipe, and a thickened portion 1d having a bulging shape can be formed inside and outside the pipe.

In the embodiment shown in FIG. 6, the inner surface mold 5 is
The outer surface mold 8D has the same structure as that shown in FIG. 2 and is provided with an opening 28 formed at the center by a two-step groove provided over the entire circumference in the pipe circumferential direction and the outer surface of the pipe being outside on both sides thereof. The structure is provided with a restriction surface 8a that restricts the expansion surface 8a from bulging. With this configuration, it is possible to form the thickened portion 1e that bulges only on the outer surface side of the pipe, and to form the enlarged diameter portion 1ea with a further increased diameter in the center of the thickened portion 1e. With this configuration, the expanded diameter portion 1ea at the center can be suitably used as a beam connecting portion whose root portion is reinforced.

In the embodiment shown in FIG. 7, the inner surface mold 5 is
With the same structure as shown in FIG. 2, the outer surface mold 8E is configured by arranging a mold element having a two-body structure composed of two constituent members 8EA and 8EB in the tube axis direction, and The two component members 8EA and 8EB are arranged with a gap equal to the width of the thickened portion to be formed in the pipe axis direction, and are fixed to a support base (not shown). Each of the two component members 8EA and 8EB is provided with a regulation surface 8a on the inner surface thereof to regulate the outer surface of the pipe so as not to bulge outward, and the space between the two component members 8EA and 8EB is Is used as the opening 30 for bulging. By using these molds 5 and 8E, it is possible to form the thickened portion 1a that bulges only on the outer surface side, as in the case of FIG. In addition,
The structure of the support base for fixing the two component members 8EA, 8EB may be one in which the two component members 8EA, 8EB are simply fixed at a fixed interval, but it is preferable that this interval be adjustable. With this configuration, the length of the thickened portion in the pipe axis direction can be changed by changing the distance between the two component members 8EA and 8EB.

As described above, it is preferable that the inner die placed in the tube has a structure capable of expanding and contracting. FIG. 8 and FIG. 9 show an example of the inner surface mold having a structure capable of expanding and contracting. The inner surface mold 5D shown in FIGS. 8 and 9 has a pair of mold elements 33, 33 arranged with the center in between, and a center at a position rotated by 90 degrees with respect to the mold elements 33, 33. A pair of mold elements 34, 34 arranged in a sandwiched manner, and a support expansion / contraction mechanism 3 for supporting and expanding / contracting these mold elements.
It is equipped with 5. Four mold elements 33, 34, 33, 3
As shown in FIG. 8 (a), the outer peripheral surface of the tube No. 4 forms a rectangular tube surface with almost no gap that fits the inner surface of the metal tube to be thickened, The structure is such that a restriction surface 5a for restricting is formed. Further, a step is formed at the end of one mold element 33 to support the end of the other mold element 34, and as shown in FIG. The structure is such that it can be pulled out inside the mold element 34. The support expansion / contraction mechanism 35
A hollow support shaft 36 and attached to the support shaft 36,
Support plate 3 for controlling the axial position of the mold elements 33, 34
7, 37, an operating shaft 38 movably held in the support shaft 36 in the axial direction, and a cam block 41 provided with cam grooves 41a, 42a respectively attached to the inner surfaces of the mold elements 33, 34. , 42 and a support member 43 attached to the operation shaft 38 and provided with a cam follower 43a that moves in the cam grooves 41a, 42a.
The support shaft 36 is formed with a slit for passing the support member 43. With these configurations, the operation shaft 38
Is moved in the axial direction with respect to the support shaft 36, the mold elements 33, 34 can be expanded or contracted in diameter depending on the shapes of the cam grooves 41a, 42a. Here, the shapes of the cam grooves 41a, 42a are the same as those of the mold elements 33, 3
When the operating shaft 38 is moved in the direction shown by the arrow B in FIG. 9 from the state in which 4 is in the expanded diameter state shown in FIG. 8A, first,
One pair of mold elements 33, 33 starts to decrease in diameter, and
As shown in (b), after the mold elements 34, 34 are retracted inside the other pair of mold elements 34, 34, both mold elements 3
It is defined that the diameters of 3, 34, 33 and 34 are further reduced. With this configuration, the mold elements 33, 34, 33, 3
4 can be reduced in diameter without interfering with each other and pulled out from the inside of the metal tube after the thickening process.

The above embodiment is for the case where a rectangular steel pipe is used as the metal pipe 1, and the inner surface mold and the outer surface mold both of which are used do not swell the inner surface or the outer surface of the tube. Although the regulation surfaces 5a and 8a for regulation are formed in a rectangular tube shape, the present invention can be applied to a metal pipe having a circular cross section such as a round steel pipe.
Further, the present invention can be applied to a metal tube having a non-circular cross section other than the rectangular shape. The inner surface mold and the outer surface mold used in that case may have a control surface that restricts the inner surface or the outer surface of the tube from bulging so as to have a shape that conforms to the inner surface or the outer surface of the tube. Figure 10
[Fig. 4] shows an inner surface mold 5E having a form capable of expansion / contraction used for a round steel pipe. This inner surface mold 5E also has four mold elements 33a, 34a, 33a, 34a arranged so as to be expandable and contractible.
And a regulation surface 5a having a shape adapted to the inner surface of the round steel pipe. Other configurations are similar to those shown in FIGS. 8 and 9.

Further, in the embodiment shown in FIG. 1, the metal tube 1
The push-in device 11 for relatively pushing the mold (the inner mold 5, the outer mold 8) into the mold from both sides of the part where the mold (the inner mold 5, the outer mold 8) is mounted, presses the both ends of the metal tube 1 respectively, and the hydraulic cylinders 13A, 13B. However, the structure of the pushing device 11 can be changed as appropriate. Another embodiment of the pushing device will be briefly described below. In the pushing device 11A shown in FIG. 11A, the hydraulic cylinder 53 is fixed to one (52B) of the movable pipe supporting members 52A and 52B that supports the metal pipe 1, and the other end (52A) of the tip of the piston rod 54 is fixed. By operating the hydraulic cylinder 53, the pipe supporting members 52A and 52B on both sides can be brought close to each other and both ends of the metal pipe 1 can be pushed to push the metal pipe 1 into the mold 8 from both sides. it can. FIG. 11 (b)
In the pushing device 11B shown in FIG. 2, the right-hand thread region 56a and the left-hand thread region 56b formed on the screw shaft 56 are screw-engaged with the movable pipe support members 52A and 52B that support the metal pipe 1, respectively, and the screw The shaft 56 is configured to be rotationally driven by a motor 57, and the rotation of the motor 57 causes the tube support members 52A and 52B on both sides to approach each other and push both ends of the metal tube 1 to move the metal tube 1 into the mold 8. Can be pushed in from both sides.

In each of the pushing devices of the above-mentioned embodiments, the die is fixed in place and the metal tube 1 is pushed into the die from both sides of the die. The pushing device used in the present invention is It is sufficient that the metal tube can be relatively pushed into the metal mold from both sides of the portion where the metal mold is mounted, and the metal mold may be moved. FIG. 12 shows a pushing device 11C according to the embodiment in that case. The pushing device 11C of this embodiment is the metal tube 1
A tube support member 52C that supports one end of the metal tube 1 is fixedly provided at a fixed position, and a tube support member 52B that supports the other end of the metal tube 1 has a movable structure.
And a structure in which the outer surface mold 8 is held by a moving carriage 62, and the moving carriage 62 is moved by a screw shaft 63 and a motor 64, and
The outer surface mold 8 is configured to be controlled to move in the same direction as the pipe support member 52B at a moving speed that is ½ of the moving speed V of the pipe supporting member 52B. Although not shown, the inner die 5 (see FIG. 1) arranged in the metal tube 1 is also moved in the same direction as the outer die 8 at the same speed. With this configuration, the pipe supporting member 52B is pushed toward the fixed pipe supporting member 52C at a speed V, and at the same time, the mold is moved in the same direction as the pipe supporting member 52C at a speed of V / 2, whereby the mold is On the other hand, the metal pipes 1 located on both sides thereof are evenly pushed. It is needless to say that the moving mechanism of the pipe support member 52B and the moving mechanism of the mold in the embodiment shown in FIG. 12 are not limited to this, and may be appropriately modified such as using a hydraulic cylinder.

[0028]

As described above, according to the method and apparatus of the present invention, the thickness of the metal pipe such as a steel pipe is increased in the desired region in the pipe axial direction by bulging the pipe meat on one or both of the inner surface and the outer surface. Can be formed efficiently in a short time, and the thickness of the thickened portion (dimension in the axial direction of the pipe) can be reduced while increasing the thickness. It has an effect that the pillar material made of the provided metal tube can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a schematic configuration of a local thickening device according to an embodiment of the present invention.

FIG. 2 (a) is a schematic cross-sectional view showing a state in which an inner die and an outer die are set on the inner and outer surfaces of a heating region of a metal tube in the apparatus shown in FIG. 1 (b). , A schematic cross-sectional view showing a state in which the metal pipe is plastically deformed by applying a compressive force (c) A schematic cross-sectional view showing a thickened portion formed in the metal pipe

FIG. 3 shows another embodiment of the present invention, in which (a),
2 (b) and (c) are shown in FIG. 2 (a), (b),
Schematic cross-sectional view of a portion similar to (c)

FIG. 4 shows still another embodiment of the present invention,
(A), (b) and (c) are respectively shown in FIG.
Schematic cross-sectional view of a portion similar to (b), (c)

FIG. 5 shows still another embodiment of the present invention,
(A), (b) and (c) are shown in FIG.
(B), schematic sectional view of the same portion as (c)

FIG. 6 shows still another embodiment of the present invention,
(A), (b) and (c) are respectively shown in FIG.
Schematic cross-sectional view of a portion similar to (b), (c)

FIG. 7 shows still another embodiment of the present invention,
(A), (b) and (c) are respectively shown in FIG.
Schematic cross-sectional view of a portion similar to (b), (c)

FIG. 8A is a schematic cross-sectional view showing an inner surface mold having a structure capable of expansion and contraction in a state where the diameter is expanded. FIG. 8B is a schematic cross-sectional view showing the inner surface mold in the middle of diameter reduction.

9 is a plan view of the inner die shown in FIG.
Schematic cross section seen in direction A

FIG. 10A is a schematic cross-sectional view showing another example of the inner surface mold in a state where the diameter is expanded, and FIG. 10B is a schematic cross-sectional view showing the inner surface mold in a state where the diameter is being reduced.

11 (a) and 11 (b) are schematic side views showing another embodiment of the pushing device.

FIG. 12 is a schematic side view showing still another embodiment of the pushing device.

[Explanation of symbols]

1 metal tube 1a, 1b, 1c, 1d, 1e thickened portion 2 heating device 3 Support device 5 Inner mold 5a Regulatory aspect 8 External mold 8a Regulatory aspect 8EA, 8EB Components of mold element 9, 20, 22, 23, 25, 26, 28, 30 Open 11, 11A, 11B, 11C pushing device 12A, 12B, 12C Pipe support member 13A, 13B hydraulic cylinder 52A, 52B, 52C Pipe support member 53 hydraulic cylinder 56, 59, 63 screw shaft 57, 60, 64 motors 62 Mobile trolley

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mitsuo Oki             2-17-8 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa               Dai-ichi Kogyo Kogyo Co., Ltd. (72) Inventor Makoto Horikiri             2-17-8 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa               Dai-ichi Kogyo Kogyo Co., Ltd. (72) Inventor Kenshi Yatabe             2-17-8 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa               Dai-ichi Kogyo Kogyo Co., Ltd. F-term (reference) 4E087 AA10 BA18 CA35 CB01 CC05                       EC01 HB01

Claims (5)

[Claims] 1. A method of forming a thickened portion by bulging tube meat on one or both of an inner surface and an outer surface in a partial area of a metal tube in the tube axis direction, the method comprising: The region to be plastically deformed to form a part is heated, and then the inner and outer surfaces of the metal pipe in the heated region are provided with openings around the entire circumference of the pipe at the positions where the tube meat is to be bulged, and at other positions. The inner surface mold and the outer surface mold having a regulation surface that regulates the inner surface of the pipe and the outer surface of the pipe so as not to bulge are attached to the
By relatively pushing the metal tube into the mold from both sides of the portion where the mold is mounted, the metal wall of the metal tube in the heated region is plastically flown into the opening from both sides thereof, A method for locally increasing the thickness of a metal pipe, which comprises forming the increased thickness by upsetting. 2. A device for forming a thickened portion by bulging tube meat on one or both of an inner surface and an outer surface in a partial region of a metal tube in the tube axis direction, the metal being arranged at a predetermined position. A heating device that is movably arranged in a desired region of the pipe in the axial direction of the pipe and that heats a desired region of the metal pipe, and a heating device that is respectively arranged on the inner surface and the outer surface of the heated region of the metal pipe to swell the meat. An inner surface mold and an outer surface mold having a restriction surface for restricting the inner surface and the outer surface of the pipe from bulging at other positions, and the metal pipe, A local thickening device for a metal pipe, comprising: a pushing device that relatively pushes into a mold from both sides of a portion where the mold is mounted. 3. A mold disposed on the side where the tube meat is bulged,
A mold element having an integral structure is arranged in the tube axis direction, and the opening is formed by a groove in the tube circumferential direction having a width equal to the tube axis direction dimension of the thickened portion provided in the mold element. The local thickening device for a metal pipe according to claim 2, wherein 4. A mold disposed on the side where the tube meat is bulged,
A mold element having a two-piece structure is arranged in the pipe axis direction, and two component members of the mold element are arranged with a gap in the pipe axis direction, and the opening is formed with the gap. The local thickening device for a metal pipe according to claim 2, wherein 5. The local thickening device for a metal tube according to claim 2, wherein the inner die has a structure capable of expanding and contracting.