JPS6216823A - Working method for pipe end - Google Patents

Abstract

PURPOSE:To work a pipe end to be welded well by holding an end of a bent pipe in a die with the end projected and expanding the end outside by press working. CONSTITUTION:A pipe 1 is bent by pressing with bending dies 3 and 4. In that time, a sloping end 2 is made at an end of the pipe 1. The dies 3 and 4 hold the end 2 in a projecting state from the dies 3 and 4 and the end 2 is struck by a press die 5 so that the end 2 is bent outside and a flange part 6 or 7 is formed at the end of the pipe 1. The flange part 6 or 7 absorbs a slope of the end 2, so that the flange part 6 or 7 has a vertical section to the axis of the pipe 1. The pipe 1 is butted on another member vertically and the flange part 6 or 7 is butt welded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method for butt welding the end of a bent metal pipe to another member so that the end of the pipe can be welded well. This invention relates to a method for processing a pipe end.

<Prior Art> Conventional 1 When making a frame such as a car seat using a metal pipe, the bent end of the pipe 11 is butt-welded to another member 12.
As shown in the figure, when the main body of the pipe 11 is bent near the end, a sink mark C occurs at the end on the side where it is stretched.
The edges are slanted.

<Problems to be solved by the invention> In a state where such a sink mark C occurs at the end of the pipe 11,
When the end of the pipe 11 is butt-welded to another member 12 at right angles, a gap is created at the sink C when the end is butted, and even if this gap is filled with molten metal, foreign matter such as spatter may be present inside the pipe 1. Means for solving the problems that occur, such as the occurrence of abnormal noise due to the welding, and the reduction of welding strength due to the small number of abutting parts at the butt points. To provide a pipe end processing method capable of processing the pipe end so that good welding is possible when the end of a bent metal pipe is butt welded to another member. It is structured as follows.

That is, the processing method of the present invention is a pipe end processing method in which the end of a bent pipe is butt welded to another member, and the pipe body is placed in a mold with the bent end of the pipe protruding. The pipe is held in place, and a press die is pressed against the end of the pipe to press the end to push the end outward to form a flange at the end of the pipe.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

FIG. 1 shows a method for processing the end of a metal pipe l used for a frame such as an automobile seat. This pipe 1 is bent into a predetermined shape near the end, but if the bent part is close to the end 2 and the bending angle is large, a sink mark will occur at the end 2, which would be different from the straight pipe. The end, which was perpendicular to , becomes inclined due to the bending process.

Therefore, the pipe l whose end portion 2 has been bent due to bending is processed into a shape suitable for welding by end processing.

This end processing device can be installed in a pipe bending machine, and is configured to strike the press die 5 toward the open end of the bending die 3.4 of the bending machine, that is, the end of the pipe to be held. , a press mold 5 is attached to the tip of a piston rod or ram of a hydraulic cylinder. The mold portion of the press die 5 is formed by protruding a trapezoidal conical portion having a tip slightly smaller in diameter than the inner diameter of the pipe 1 on a flat portion.

First, a straight pipe is placed in a bending die 4 of a bending machine with its end slightly exposed, and by pressing the bending dies 3 and 4 together, the pipe 1 is bent to a predetermined bending angle. Ru. At this time, as shown in Fig. 1, the vicinity of the end of the pipe body is bent downward, so a sink mark that increases upwards occurs at the end of the pipe 1, and the inclined end 2
is made.

Next, with the pipe 1 held in the bending die 3.4, the press die 5 is struck toward the end 2 of the pipe l. Then, the end 2 of the pipe l is bent outward, as shown in FIG.
As shown in B, a flange 6 or 7 is formed at the end of the pipe 1. This collar portion 6.7 absorbs the inclination of the end portion 2 and has an end face perpendicular to the axis of the pipe 1, so that it has a substantially oval frontal shape as shown in FIG.

As shown in FIG. 4, the pipe 1 with the perpendicular flange 6 or 7 formed at its end is vertically abutted against another member 8 (for example, a member made by flattening the end of the pipe). Then, the flange of the pipe I is butt welded. At this time, since the vertical and approximately egg-shaped flange 6 or 7 is formed at the end,
Since there is no gap in the butt and the contact area with another member 8 is large, the joint can be made with sufficient welding strength, and foreign matter such as spatter will not be mixed into the pipe 1.

<Effects of the Invention> As explained above, according to the pipe end processing method of the present invention, the pipe body is held in a mold with the bent end of the pipe protruding, and the pipe end is The pipe was constructed in such a way that a press die was pressed against it to open the end outwards, forming a flange at the end of the pipe.
Even if a pipe has sink marks due to bending near the end of the pipe, it can be butted vertically to another member without any gaps, and a good butt weld can be performed to ensure sufficient welding strength □
I can show off the degree. Also, pipe bending □
Because the end processing can be performed continuously as part of the process, it requires fewer man-hours and is extremely efficient compared to methods such as applying the pipe to a cutting machine or cutter after one bending process and shaping the slanted end vertically. The end of the pipe can be machined.

[Brief Description of the Drawings] Figures 1 to 4 show embodiments of the present invention; Figure 1 is a cross-sectional explanatory diagram showing a method of processing a pipe end; Figures 2A and 2B; is a cross-sectional view of the pipe end, Fig. 3 is a front view of the pipe end, Fig. 4 is a front view of the pipe butt 6 weld, and Fig. 5 is a front view showing the conventional pipe joint state. be. l...pipe, 2...end, 3.4...bending mold, 5...pressing mold, 6.7...flange, 8...other member/patent application Shin Dainichi Spring Manufacturing Co., Ltd. Patent Attorney Ii 1) Akio 1-1 1... Shi, - @2 Figure A

Claims (1)

[Claims] In a pipe end processing method in which the bent end of the pipe is butt welded to another member, the pipe body is held in a mold with the bent end of the pipe protruding, and the pipe end is welded to another member. 1. A method for processing an end of a pipe, characterized by forming a flange at the end of the pipe by pressing a press mold against the end of the pipe to push the end outward.