JPH11138273A - Welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method capable of improving productivity by controlling the swelling of an excess wall. SOLUTION: An annular step part 7 is formed in the inner peripheral side of one end part in a tube 1, a gap 9 is formed between a side wall 7b of the step part 7 and a cap which is placed on a bottom surface part 7a of the step part 7. Further, an annular notch part 8 is formed in the end part of the tube 1, and a first and second electrodes are electrically energized while compressing the cap 2 against the tube 1. The excess wall 5 is guided into the gap 9, most of the excess wall 5 escapes into a widening part 10 side. Therefore, the excess wall 5 swelling into the inside of the tube 1 becomes extremely little. The widening part 10 is formed by providing the notch part 8, a large quantity of excess wall 5 is allowed to house in the widening part 10, and whereby the excess wall 5 is controlled to swell out of one end part in the tube 1. Thus, an excess wall shaving process is unnecessitated, whereby productivity is improved that much.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for welding a cap to an open end of a pipe.

[0002]

2. Description of the Related Art Conventionally, as an example of a method of welding a cap to an open end of a pipe, there is a welding method disclosed in Japanese Patent Application Laid-Open No. 56-74396. In this welding method, as shown in FIG. 6, a cap 2 is placed on the open end of a tube 1, and an electrode (referred to as a first electrode for convenience) 3 is placed on the cap 2. Two electrodes (for convenience, referred to as a second electrode) 4 are arranged so as to face each other on the side surface, and a current is applied to the first and second electrodes 3 and 4 so as to be applied to the open end of the tube 1. The cap 2 is welded.

[0003]

In the above welding method, for example, as shown in FIG.
5 on the outer and inner peripheral portions of the
Are formed to swell. For this reason, it is required to cut off the swollen waste meat 5 for regulation of the outer diameter and the inner diameter, and the productivity may be reduced accordingly.

[0004] The present invention has been made in view of the above circumstances, and has as its object to provide a welding method capable of suppressing the bulging of waste meat and improving the productivity.

[0005]

According to the first aspect of the present invention,
A method of placing a first electrode on a cap disposed at one end of a tube and welding the cap to the tube using the first electrode and a second electrode disposed around the tube. Forming an annular step on the inner periphery of one end of the tube, forming a gap between the side wall of the step and the outer periphery of the cap, and placing the cap on the bottom of the step. The current is supplied to the first and second electrodes while pressing the cap against the tube.

According to a second aspect of the present invention, in the configuration of the first aspect, an annular notch is formed in an upper end portion of a portion of the step portion of the pipe where the side wall is formed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a welding method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5, the same members and portions as those shown in FIGS. 6 and 7 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In FIG. 1, the base 6 includes:
A tube 1 is mounted. An annular step 7 is formed on the inner peripheral side of one end (upper side in FIG. 1) of the tube 1 as shown in FIG. The stepped portion 7 includes an annular bottom portion 7a having a predetermined width,
An annular side wall 7b having a predetermined radius is connected to the bottom surface 7a at right angles. A substantially funnel-shaped (annular) cutout 8 is formed at the upper end of the end of the tube 1 where the side wall 7b is formed. Since the notch 8 is formed in this manner, a wider portion 10 wider than the gap 9 described below is connected to the gap 9 between the end of the tube 1 and the outer periphery of the cap 2. Is formed.

The cap 2 is placed on the bottom 7a of the step 7. As shown in FIG. 5, the cap 2 has a structure in which a projection is formed at the center of a substantially disk-shaped member by press drawing or the like, and an annular cap body 2a and an inner peripheral side of the cap body 2a are formed. A circular reference wall 2c having a predetermined diameter is formed at a connecting portion between the projection 2b and the cap main body 2a. The outer diameter of the cap body 2a is smaller than the inner diameter of the side wall 7b of the step 7, and when the cap 2 is placed on the bottom 7a of the step 7,
A gap 9 is formed between the outer peripheral side of a and the side wall 7b.

A first electrode 3 is placed on the cap 2, and two second electrodes 4, 4 arranged opposite to each other are brought into contact with the tube 1, and the first and second electrodes 3 and 4 are brought into contact with each other. Is applied to the electrodes 3 and 4 so that the cap 2 is welded to one end (open end) of the tube 1. The first electrode 3 and the second electrode 4 are driven by a hydraulic cylinder device. A hydraulic cylinder device for driving the first electrode 3 is a pressing cylinder device 11, and two hydraulic cylinder devices for driving the second electrode 4 are each a first cylinder device 12 for clamping (left side in FIG. 1). , The second cylinder device 13 for clamping (right side in FIG. 1).

The first electrode 3 has a substantially columnar shape, and the upper end is held by the mounting member 11a of the pressing cylinder device 11. The lower end surface of the first electrode 3 has the same diameter as the reference wall 2c of the cap 2 (the reference wall 2c of the cap 2 can be inserted).
Is formed. The annular portion (contact portion) 3a left by the formation of the concave portion 14 is a cap 2
Of the main body 2a. The cap 2 is placed on the upper end of the tube 1 by a manual operation or an appropriate mechanism, and the first electrode 3 descends, whereby the reference wall 2 c
Is inserted into the concave portion 14. Thereby, the cap 2 is positioned and the cap body 2
The gap 9 between the outer peripheral side of a and the side wall 7b is formed to be uniform over the entire circumference.

The pressing cylinder device 11 is fixed to a mounting plate 15 fixed on one end of the tube 1. The piston rod 11b of the pressing cylinder device 11 extends toward the pipe 1 through a hole (symbols omitted) of the mounting plate 15, and has a mounting member 11a at a distal end. The first electrode 3 is held by the mounting member 11a.

The second electrode 4 has a substantially prismatic shape.
As shown in FIG. 4, an arc-shaped concave surface portion 4a having the same radius as the outer periphery of the tube 1 is formed at one end of the second electrode 4,
The concave portion, that is, the second electrode 4 can come into good contact with the tube 1. The other ends of the one (left side in FIG. 1, hereinafter referred to as left side) and the other (right side in FIG. 1, hereinafter referred to as right side) second electrodes 4, 4 are respectively connected to the first and second clamping members.
The attachment members (hereinafter, referred to as left and right attachment members) 12a and 13a of the second cylinder devices 12 and 13 are held. The effective pressure receiving area of the second holding cylinder device 13 is larger than the effective pressure receiving area of the first holding cylinder device 12. In addition, both cylinder devices 12,
13 is adapted to be activated by a fluid of equal pressure.

First and second cylinder devices 12, 1 for clamping
3 is mounted laterally to a sub-base 18 provided at a higher position than the base 6 via brackets 16 and 17, respectively. First and second cylinder devices 1 for clamping
The piston rods 12b and 13b of the second and the thirteenth can be extended toward each other, and each of the distal ends has a
The left and right attachment members 12a and 13a are provided. The left and right second electrodes 4 and 4 are held by the left and right attachment members 12a and 13a, respectively.

Below the right mounting member 12a, an L-shaped stopper 19 is mounted so as to be movable in the advancing and retreating directions of the piston rods 12b and 13b (directions of arrows A and B in FIG. 1). When the right mounting member 12a moves in the direction of arrow A, it contacts the stopper 19 and stops at that position.

In this embodiment, when the cap 2 is welded to the open end of the tube 1, the tube 1 is erected on the base 6 and is located between the left and right second electrodes 4, 4. Position. At this time, the stopper 19 is moved and adjusted in advance. That is, the tube 1 is sandwiched between the left and right second electrodes 4, 4 so that the central axis of the tube 1 coincides with the central axis of the step 7. In this state, the stopper 19 is attached to the right mounting member 12a.
And the stopper 19 is fixed to the base 6, and the position of the stopper 19 is set as the set position of the stopper 19 in this case.

Then, the left and right second electrodes 4, 4,.
When the first and second cylinder devices 12, 13 for clamping are operated in a state where the first electrode 3 is separated from the tube 1, the second electrode 4 on the right moves in the direction of arrow A to move the right electrode on the right. When the mounting member 12a contacts the stopper 19, it is stopped at a predetermined position. The second electrode 4 on the left side moves in the direction of arrow B to abut the tube 1 and presses it further. Thus, the tube 1 is held at a predetermined position by the left and right second electrodes 4 and 4. That is, the tube 1 is sandwiched between the left and right second electrodes 4, 4, and the sandwiched tube 1 is further moved by the first cylinder device 12 for sandwiching through the left second electrode 4 through the arrow B. Direction, but the second
Since the effective pressure receiving area of the cylinder device 13 is larger than the effective pressure receiving area of the first cylinder device 12 for clamping, the force with which the second electrode 4 on the right receives the tube 1 is increased by the second electrode 4 on the left. Since the second electrode 4 on the right side does not move while stopped at a predetermined position, the second electrode 4 on the right side is held at the predetermined position.

Next, in this state, the cap 2 is placed on the bottom surface 7a of the step 7 of the tube 1 by a manual operation or an appropriate mechanism. Next, when the pressing cylinder device 11 is operated, the first
As the electrode 3 descends, the concave portion 14 gradually fits into the reference wall 2c of the cap 2, whereby the center axis of the cap 2 and the center axis of the tube 1 are aligned, and both are centered, and the cap body 2a A gap 9 having a uniform width over the entire circumference is formed between the outer peripheral side of the base and the side wall 7b.

Next, in this state, the pressing cylinder device 11
Is operated to press the cap 2 against the tube 1 while the first,
When a welding current is applied between the second electrodes 3 and 4, the cap 2 is welded to the open end of the tube 1. In this case, as shown in FIG. 3, for example, a contact portion (for example, a portion indicated by reference symbol E) of the cap 2 and the tube 1 generates heat by energization, while the cap 2 is pressed against the tube 1 by the operation of the pressing cylinder device 11. As a result, the cap 2 and the pipe 1 are fitted so that the contact portion E is crushed. Then, the meat (canned meat 5) generated by the crushing of the contact portion E or the like (partly melting) escapes while being guided by the gap 9 and is stored in the gap 9 and the widened portion 10.

As described above, the gap 9 is formed between the cap 2 and the side wall 7 b of the step 7, and the cap 2 is attached to the bottom 7 a of the step 7.
The waste 5 is guided to the gap 9 and most of the waste 5 escapes to the widened portion 10 side. For this reason, the amount of waste 5 (so-called oxide scale or the like) swelling inside the tube 1 is extremely reduced. An annular notch 8 is formed at the upper end of the end of the tube 1 where the side wall 7b is formed.
The widened portion 10 wider than the gap 9 is formed between the end of the tube 1 and the outer peripheral portion of the cap 2. 10 can be stored. For this reason, it is possible to suppress the waste 5 from bulging from one end of the tube 1.

As described above, the amount of waste 5 swelling inside the tube 1 is extremely reduced, and the swelling of the waste 5 from one end of the tube 1 can be suppressed. This eliminates the need for a step of shaving the required meat, thereby improving productivity.

After the cap 2 is welded to the pipe 1 as described above, the first and second cylinder devices 1 for pressing and holding are held.
The first electrode 3, the left and right second electrodes 4, 4 are separated from the cap 2 and the tube 1 by operating the tubes 1, 12, 13 and the tube 1 to which the cap 2 is welded is taken out in this state.

In the above embodiment, the case where the notch 8 is formed is taken as an example. However, the present invention is not limited to this, and the size of the gap 9 is adjusted so that the waste 5 is accommodated without forming the notch 8. May be set.

[0023]

According to the first aspect of the present invention, a gap is formed between the side wall of the step portion of the tube and the outer peripheral side of the cap, and the cap is placed on the bottom portion of the step portion. Since the waste generated at the contact portion of the tube and the cap is easily guided to the gap side and escapes, the waste swelling inside the tube can be reduced. In the invention according to claim 2, an annular notch is formed at the upper end portion of the portion forming the side wall of the step portion of the tube, so that the gap between the side wall of the step portion of the tube and the outer peripheral side of the cap is formed. Since a widened portion wider than the gap is formed, a large amount of waste can be stored in the widened portion. For this reason, it can control that waste meat bulges from one end of a pipe.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a part of the tube and the cap of FIG. 1;

FIG. 3 is a sectional view showing a welded state of the pipe and the cap of FIGS. 1 and 2;

FIG. 4 is a partial sectional view of FIG. 1;

FIG. 5 is a sectional view of the cap of FIG. 1;

FIG. 6 is a sectional view showing an example of a conventional welding method.

FIG. 7 is a sectional view showing a welding state of a pipe and a cap according to an example of the conventional welding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tube 2 Cap 3 1st electrode 4 2nd electrode 7 Step 7a Bottom part 7b Side wall 8 Notch

Claims (2)

[Claims] 1. A first electrode is placed on a cap disposed at one end of a tube, and the first electrode and a second electrode disposed around the tube are used to attach the first electrode to the tube. In the method of welding a cap, an annular step is formed on the inner peripheral side of one end of the pipe, and a gap is formed between a side wall of the step and an outer peripheral side of the cap to thereby connect the cap to the step. Place the cap on the bottom, press the cap against the tube,
A current supply to the electrodes. 2. The welding method according to claim 1, wherein an annular notch is formed in an upper end portion of a portion of the step portion of the pipe where a side wall is formed.