JPH08103819A - Manufacture of round tube with tubular outside projection - Google Patents

Abstract

PURPOSE: To manufacture a round tube with a tubular outside projection at low cost and for the diameter larger than the one by the conventional method. CONSTITUTION: This is a manufacture of a round tube a through-hole of which is formed on the circumferential wall and a tubular outside projection of which is also formed integrally around the through-hole. A plurality of tube stock is prepared which is in circular arc shape in cross section and which is made of aluminum extruded material. Bending is performed on each tube stock so as to reduce the curvature and also to uniformize the radius of curvature among all tube stocks 1A. Press work is performed at least on one tube stock 1A to form a tubular bulged part 2 with the tip end closed. A through-hole 3 is formed on the closed wall at the tip end of the tubular bulged part 2. All tube stocks 1A are combined to form one cylinder and the adjacent ones are welded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a peripheral wall formed with a through hole and a cylindrical outer protruding portion integrally formed around the through hole. For example, a cylindrical outer protruding portion used for a bus bar is provided. A method for manufacturing a round pipe with a section.

[0002] In this specification, the term "aluminum" shall include aluminum alloys in addition to pure aluminum.

[0003]

2. Description of the Related Art For example, a bus bar having an outer diameter of 400
mm or more, the thickness of the peripheral wall is 10 mm or more, the through hole is formed in the peripheral wall, and the cylindrical outer protruding portion is integrally formed with the cylindrical outer protruding portion around the through hole. A round pipe with a rod may be used.

Conventionally, such a round pipe with an outward protruding portion is formed by forming an aluminum extruded shape round pipe, then subjecting it to a bulge process to form a cylindrical bulging portion on the peripheral wall, and then forming a tubular pipe. It was manufactured by forming a through hole in the tip closing wall of the bulging portion.

[0005]

However, the conventional manufacturing method requires a large-sized extruder, and
The bulge forming die and the bulge forming equipment are also required to be large in size, and there is a problem in that the cost thereof becomes high and the difficulty of processing becomes high. Furthermore, with the conventional manufacturing method, it was possible to manufacture only those having an outer diameter of about 480 mm at the maximum.

An object of the present invention is to provide a method for manufacturing a round pipe with a cylindrical outer protruding portion that solves the above problems.

[0007]

In the method of manufacturing a round pipe with a cylindrical outer protruding portion according to the present invention, a through hole is formed in a peripheral wall and a cylindrical outer protruding portion is integrally formed around the through hole. A method of manufacturing round pipes, in which a plurality of metal extruded profile pipe materials with arcuate cross-sections are made, and each pipe material is bent to reduce its curvature and all pipe materials Have the same radius of curvature, at least one pipe material is pressed to form a cylindrical bulging portion with a closed tip, and a through hole is formed in the tip closing wall of the cylindrical bulging portion. thing,
And combining all pipe stocks to form a cylinder and welding adjacent ones to each other.

In the above, after bending each pipe material to reduce its curvature and equalizing the curvature radii of all the pipe materials, the pipe material to be pressed in the subsequent step is subjected to the O material treatment. It is preferable to keep. When such an O material treatment is applied, the elongation of the material is increased and the workability during the press working in the subsequent process is improved.

[0009]

According to the method of manufacturing a round pipe with a cylindrical outward protruding portion of the present invention, a plurality of metal extruded profile pipe materials having an arc-shaped cross section are formed, and then each pipe material is bent. Since the curvature is made small and the radii of curvature of all pipe materials are made equal, the extrusion apparatus used can be miniaturized as compared with the conventional method of extruding the entire round pipe. Further, since at least one pipe material is press-formed to form the tubular bulging portion with the closed tip, the round pipe is bulged to form the tubular bulging portion with the closed tip. The size of the mold and equipment can be reduced as compared with the conventional method. Moreover, the degree of processing difficulty is reduced. Furthermore, a plurality of metal extruded profile pipe materials having an arc cross section are made, and each pipe material is bent to reduce its curvature, and all pipe materials have the same radius of curvature, and at least 1
By pressing one pipe material to form a cylindrical bulge with a closed end, a through hole is formed in the tip closing wall of the tubular bulge, and then all pipe materials are made into one cylinder. Since they are combined so as to be formed and adjacent ones are welded to each other, it is possible to manufacture up to a maximum outer diameter of about 1000 mm.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 shows a round pipe with a cylindrical outer protruding portion made of aluminum manufactured by the method of the present invention.

In FIG. 5, a round pipe (10) made of aluminum and having a cylindrical outer protruding portion has a through hole (11) formed in its peripheral wall, and a cylindrical outer protruding portion (around the through hole (11)). 12) is integrally formed.

Next, a method for manufacturing such a round pipe (10) with a cylindrical outward protruding portion will be described with reference to FIGS.

First, a plurality of, preferably 2 to 4 aluminum pipe materials having an arcuate cross section (cross section lacking circular shape).
(1) is extruded (see FIG. 1). Next, each pipe material (1) is bent to reduce its curvature, and the radius of curvature of all pipe materials (1A) with reduced curvature is made equal (see FIG. 2). Next, one of all pipe materials (1A) with a reduced curvature (1A)
After forming the cylindrical bulging part (2) whose tip is closed by press working, the through hole (3) is formed in the tip closing wall of the cylindrical bulging part (2) (see Fig. 3) ). After that, all pipe materials (1A) are combined so as to form one cylinder, and adjacent ones are welded to each other (see FIG. 4). In this way, the round pipe (10) with the cylindrical outward protruding portion is manufactured.

In the above, after bending each pipe material (1) to reduce its curvature and equalizing the radius of curvature of all the pipe materials (1A) whose curvature has been reduced, press working is performed in a subsequent step. Pipe material (1
It is preferable that O) is treated in A). When such an O material treatment is applied, the elongation of the material is increased and the workability during the press working in the subsequent process is improved. .

[0016]

As described above, according to the method for manufacturing the round pipe with the cylindrical outward protruding portion of the present invention, the size of the extrusion apparatus used can be reduced as compared with the conventional method. The bending die and equipment can be downsized. Moreover, the degree of processing difficulty is reduced. Therefore, the manufacturing cost is reduced. Furthermore, the maximum outer diameter is 10
It becomes possible to manufacture a product having a diameter of about 00 mm.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an extrusion-shaped pipe material having a cross-section circular arc shape.

FIG. 2 is a cross-sectional view showing a pipe material that is bent to reduce its curvature.

FIG. 3 is a cross-sectional view showing a pipe material in which a tubular bulging portion having a closed tip is formed by press working and then a through hole is formed in a tip closing wall of the tubular bulging portion.

FIG. 4 is a cross-sectional view showing the combination of all pipe blanks to form one cylinder.

FIG. 5 is a perspective view of a round pipe with a cylindrical outer protruding portion manufactured by the method of the present invention.

[Explanation of symbols]

 (1) Pipe material (1A) Pipe material (2) Cylindrical bulge (3) Through hole

Claims (1)

[Claims] 1. A method for manufacturing a round pipe in which a through hole is formed in a peripheral wall and a cylindrical outer protruding portion is integrally formed around the through hole, the method comprising: Tip by making extruded pipe material, bending each pipe material to reduce its curvature and equalizing the radius of curvature of all pipe materials, and pressing at least one pipe material Forming a closed tubular bulge, forming a through hole in the tip closing wall of the tubular bulge, and combining all pipe materials to form one cylinder and adjoining A method for manufacturing a round pipe with a cylindrical outward protrusion, which comprises welding pieces to each other.