JP2004268049A - Method and apparatus for producing thin tube blank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing a thin tube blank with which a long thin tube blank can be produced with a mush-seam welding method while applying sufficient welding load. <P>SOLUTION: The edge parts of a metallic plate 10 formed into tubular-state are piled up and the piled-up part 11 is mush-seam welded between electrode rolls 12, 13 made a pair on the inside and the outside of the tube. At the opposite side of the electrode rolls, auxiliary rolls 17, 18 made a pair on the inside and the outside of the tube are disposed, and the electrode roll 13 at the inside of the tube is brought into contact with the auxiliary roll 17. While receiving the welding load acted on the electrode roll 13 with the auxiliary roll, the welding can be performed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing a thin-walled tube for hydroforming a thin-walled metal part.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-120024
The hydroforming method is a processing method in which a metal tube is set in a mold, and a shaft punch and high internal pressure are applied from the tube end by a seal punch to plastically deform the tube along the inner surface shape of the mold. In addition, since a complicated shape can be formed without welding, it is attracting attention as a forming method for automobile parts and the like that require lightness. Conventionally, hydroforms have been used for the production of relatively thick parts, so that an electric resistance welded steel pipe as shown in Patent Document 1 is generally used as a raw pipe.
[0004]
However, recently, hydroforming thin metal parts has been studied, and in that case, it is required to make the raw pipe thin. However, if the plate thickness t is reduced with respect to the diameter D of the raw tube and t / D ≦ 0.02, the forming of the ERW steel pipe becomes unstable, and the welding quality is not stable. For this reason, when attempting to use a thin-walled tube for hydroforming a thin-walled, large-diameter part, an ERW steel tube cannot be used. Therefore, the present inventor tried to use a thin-walled tube for hydroforming that was formed by winding a metal plate into a tubular shape and butt-welding the end faces thereof by laser welding or TIG welding.
[0005]
However, thin-walled pipes that have been butt-welded by laser welding or TIG welding have a molten solidified structure similar to the plate thickness perpendicular to the circumferential direction in the welded part. It was found that there was a risk of the tube breaking, which proved to be unsuitable as a thin-walled tube for hydroforming.
[0006]
For this reason, the inventor prototyped a thin-walled tube by mash seam welding between the ends of a metal plate formed by sheet winding, and succeeded in hydroforming a thin-walled metal part. However, since mash seam welding is a method of conducting welding while pressurizing a welding portion between a pair of electrode rolls 1 and 2 as shown in FIG. 5, the electrode roll 2 must be disposed in the pipe. The electrode roll 2 inside the tube must be supported by a cantilever arm 3 extending from the tube end of the thin-walled tube. However, as the tube length increases, the cantilever arm 3 also increases, and cannot support a welding load. For this reason, there was a problem that only a thin tube having a short tube length could be manufactured.
[0007]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems, and provides a method and an apparatus for manufacturing a thin-walled tube capable of manufacturing a long-walled thin-walled tube by a mash seam welding method while applying a sufficient welding load. It was done in.
[0008]
[Means for Solving the Problems]
The method of manufacturing a thin-walled tube of the present invention made in order to solve the above-mentioned problem, when mash seam welding between a pair of electrode rolls inside and outside the tube by overlapping the ends of a tubular shaped metal plate, A pair of auxiliary rolls inside and outside the tube are arranged on the opposite side of these electrode rolls, and the electrode roll inside the tube and the auxiliary roll are brought into contact with each other, so that the welding load acting on the electrode roll inside the tube is controlled by the auxiliary roll. It is characterized by mash seam welding while receiving.
[0009]
Further, the thin-walled tube manufacturing apparatus of the present invention is a thin-walled tube manufacturing apparatus for mash seam welding an end of a metal plate formed into a tubular shape, comprising a pair of electrode rolls and a pair of auxiliary rolls. The electrode roll and the auxiliary roll are arranged in such a manner that the rolls inside the tube of the auxiliary roll are brought into contact with each other. In addition, the position of the auxiliary roll with respect to the electrode roll can be moved in the pipe axis direction, and can be adapted to a change in the pipe diameter.
[0010]
As described below, according to the present invention, mash seam welding can be performed while receiving a welding load acting on an electrode roll by an auxiliary roll disposed on the opposite side of the electrode roll. Therefore, there is no need to receive a welding load from outside the tube at the tip of the cantilever arm as in the related art, and a thin-walled tube having a short tube length can be manufactured freely.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
1 and 2 are cross-sectional views showing a first embodiment of the present invention. Reference numeral 10 denotes a metal plate such as a thin steel plate formed by sheet winding, and reference numeral 11 denotes an overlapped portion. Reference numerals 12 and 13 denote paired electrode rolls for mash seam welding the overlapped portion 11, and an electrode plate 14 is provided on the peripheral surface thereof. These electrode rolls 12 and 13 are supported from outside the tube by arms 15 and 16.
[0012]
In the present invention, a pair of auxiliary rolls 17 and 18 are arranged on the opposite side of the electrode rolls 12 and 13 about the tube axis. The auxiliary rolls 17 and 18 are arranged with the metal plate 10 formed by sheet winding therebetween. The electrode roll 13 on the inner side of the tube and the auxiliary roll 17 on the inner side of the tube are in contact with each other as shown, and the electrode roll 13 is supported by the auxiliary roll 17, and the auxiliary roll 17 is further supported by the auxiliary roll 18. These auxiliary rolls 17 and 18 are also supported from outside the tube by arms 19 and 20.
[0013]
For mash seam welding, for example, a welding load of about 1 ton is applied in the downward direction in FIG. 1 by the electrode roll 12, and a load substantially equal to that acts on the electrode roll 13 inside the tube. In the conventional method shown in FIG. 5, this load is supported by the tip of the cantilever arm 3, whereas in the apparatus of the present invention, the downward load acting on the electrode roll 13 is applied to the outside of the tube via the auxiliary roll 17. To the auxiliary roll 18. Since the auxiliary roll 18 on the outside of the tube can have sufficient strength, there is no problem even if the welding load is increased.
[0014]
According to the present invention, the overlapped portion 12 is mash seam-welded while moving the metal plate 10 formed in the plate winding direction in the tube axis direction, so that a long thin-walled tube can be easily manufactured. In the present invention, the arm 16 and the arm 19 also need to be longer than the length of the thin-walled tube. However, since it is not necessary to support a welding load as in the conventional case, it is not necessary to provide strength.
[0015]
If the positions of the auxiliary rolls 17 and 18 with respect to the electrode rolls 12 and 13 can be moved in the tube axis direction as shown in FIG. 3, the contact position between the electrode roll 13 and the auxiliary roll 17 changes, so that the diameter of the tube is reduced. It becomes possible to respond to changes.
[0016]
Further, as shown in FIG. 4, the auxiliary roll 18 on the outside of the tube can be firmly fixed to the base 21.
[0017]
The thin tube thus manufactured can be hydroformed in the same manner as in the past, and it is possible to hydroform a thin metal component that could not be formed because the production of the tube was conventionally difficult.
[0018]
【The invention's effect】
As described above, according to the method and apparatus for manufacturing a thin-walled tube of the present invention, a thin-walled tube having a long pipe length can be manufactured by a mash seam welding method while applying a sufficient welding load. Therefore, no welding defects occur. Further, according to the invention of claim 3, it is possible to easily cope with thin-walled pipes having different pipe diameters.
[Brief description of the drawings]
FIG. 1 is a sectional view in the tube axis direction showing an embodiment of the present invention.
FIG. 2 is a sectional view in a direction perpendicular to the tube axis of FIG.
FIG. 3 is a sectional view in the tube axis direction showing a state where the auxiliary roll is moved in the tube axis direction.
FIG. 4 is a sectional view in the tube axis direction showing another embodiment of the present invention.
FIG. 5 is a sectional view in a tube axis direction showing a conventional method.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 conventional electrode roll 2 electrode roll 3 cantilever arm 10 sheet-wound metal plate 11 overlapping portion 12 electrode roll 13 electrode roll 15 arm 16 arm 17 auxiliary roll 18 auxiliary roll 19 arm 20 arm 21 base

Claims (3)

When mash seam welding is performed between the electrode rolls forming a pair inside and outside the tube by overlapping the ends of the metal plate formed into a tubular shape, an auxiliary roll forming a pair inside and outside the tube is arranged on the opposite side of these electrode rolls, A method for manufacturing a thin-walled tube, wherein a mash seam welding is performed by contacting an electrode roll inside a tube with an auxiliary roll and receiving a welding load acting on the electrode roll inside the tube with the auxiliary roll. An apparatus for manufacturing a thin-walled tube for performing mash seam welding on an end of a metal plate formed into a tube, comprising a pair of electrode rolls and a pair of auxiliary rolls, and a tube of these electrode rolls and auxiliary rolls. An apparatus for manufacturing a thin-walled tube, wherein inner rolls are arranged in contact with each other. 3. The apparatus according to claim 2, wherein the position of the auxiliary roll with respect to the electrode roll is movable in the tube axis direction.

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