JPH0239354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electric resistance welding tube welding device, and in particular, the present invention relates to an electric resistance welding tube welding device, and in particular, the present invention relates to an electric resistance welding tube welding device that uses a plurality of energizing devices to completely weld up to the rear end of the electric resistance welded tube without causing welding defects. The present invention relates to an electric resistance welding pipe welding device equipped with a tip.

BACKGROUND ART In welding electric resistance welding pipes, there is a portion at the rear end of the pipe that remains unwelded, but this portion cannot be used as a product. Conventionally, a method for preventing this has been to attach a welding auxiliary piece to the rear end of the tube by welding or pressure welding. However, this method also requires man-hours for fixing the welding auxiliary piece and removing it in a subsequent process, which impedes productivity. There is also the problem of having to use extra material (ie welding aids).

Therefore, the present applicant previously proposed an electric resistance welding pipe welding device that improves the above-mentioned conventional drawbacks in Japanese Patent Application Laid-Open No. 59-47075 (Japanese Patent Application No. 54-157645).

That is, the electric resistance welding pipe welding device according to JP-A No. 59-47075 is equipped with an energizing jig for the rear end that can come into contact with the rear end of the material to be welded and can also come into contact with the energizing tip during movement. It is something.

According to the above-mentioned electric resistance welding pipe welding device, it is now possible to completely weld to the rear end of the pipe without fixing the welding auxiliary piece to the rear end of the pipe as was previously done. .

Problems to be Solved by the Invention However, according to the above, when there is a step between the energizing jig and the material to be welded, or when the energizing piece and the material to be welded are separated, There was a problem in that the current-carrying tip became separated from the current-carrying jig and the material to be welded, and smooth welding of the rear end of the material to be welded could not be performed. This is now shown in Figure 4 A.
Referring to B and C, 2 is a material to be welded (hereinafter referred to as a workpiece), 36 is a current-carrying jig, and a current-carrying piece 39 is provided at the tip thereof to be applied to the inside of the rear end of the workpiece. Reference numeral 8 denotes a current-carrying chip attached to the support plate 22a.

In the case of figure A above, the workpiece 2 is higher than the top surface of the energizing jig 36, in the case of figure B, conversely, the energizing jig 36 is higher than the workpiece 2, and furthermore, in the case of figure C, the rear end of the workpiece 2 There is a gap between the edge and the energizing jig 36, and in any of the above cases, the energizing chip 8 is connected to the workpiece 2.
When moving from the energizing jig 36 to the energizing jig 36, the energizing chip 8 temporarily floats up, resulting in poor energization.
As a result, welding defects at the rear end of the workpiece could not be prevented until completion.

Means for Solving the Problems The present invention solves the above-mentioned problems, namely, the vicinity of both sides of a material to be welded which is formed into a cylinder by bending both sides of a plate member so as to face each other. It is provided with a pair of energizing chips that supply power to both sides and weld the joint, and an energizing jig that comes into contact with the rear end of the workpiece and moves together. In the electric resistance welding pipe welding apparatus, two sets of the above-mentioned pairs of energizing tips are provided along the traveling direction of the welded material, and the energizing tips on the same side on both opposing sides are electrically connected to each other. The first feature of the present invention is that the current-carrying chip includes:
A second feature of the present invention is that the distance between the pair of current-carrying chips provided on the rear side when viewed from the moving direction of the welded material is larger than the distance between the other pair of opposing current-carrying chips. be.

Embodiments The present invention will be explained below with reference to embodiments shown in FIGS. 1 to 3.

FIG. 1 is a perspective view of the entire electric resistance welding pipe welding device.

In the figure, 1 is a bed, and 2 is a workpiece (material to be welded) that moves on the bed. Three sets of pinch rolls 3, 4, and 5 are provided on the bed 1 as means for sending out the work 2, and a pair of squeeze rolls 6 for applying pressure to the work 2 from both sides are provided.

In this embodiment, the workpiece 2 is a plate-like member formed into a square tube shape with both sides 7 facing each other. 8 is a pair of energizing chips,
Reference numeral 8a denotes a pair of current-carrying chips provided on the current-carrying chip 8 with their positions shifted in the running direction of the workpiece 2;
As shown in Figure A, the current-carrying chips 8 are electrically connected to each other on the same side across the welded portion. Each energizing chip 8, 8a is attached to the tip of the contact support device 22. Reference numeral 20 denotes a matching transformer, at the bottom of which the contact support device 22 is attached (details thereof will be explained later with reference to FIG. 3).
The energizing chips 8, 8a are brought into contact with the vicinity of both side portions 7 during feeding of the workpiece 2, and are energized to heat and weld the both side portions 7 pressurized by the squeeze roll 6 with high frequency. It is something to do.

Energizing chips 8, 8a and an energizing jig 36 to be described later
must be moved depending on the size of the workpiece 2, etc., so it has the following structure. That is, a support member 10 is provided across two frames (not shown in the figure) that are substantially perpendicular to the workpiece 2, and a vertically movable table 12 is provided in the dovetail groove of the support member 10 so as to be freely movable in the longitudinal direction of the workpiece 2. are fitted. A hydraulic cylinder 13 for moving the vertically movable table 12 along the dovetail groove is fixed to the support member 10.

The vertical moving table 12 is also provided with a dovetail groove, into which the horizontal moving table 15 is fitted so as to be movable in a direction perpendicular to the longitudinal direction of the workpiece 2. And the vertical moving table 12
A hydraulic cylinder 16 for moving the lateral movement table 15 along the dovetail groove is fixed to. The horizontal moving table 15 includes a hydraulic cylinder 1 having a dovetail groove and movably moving the vertical moving table 18 in the vertical direction.
9 is fixed. In the figure, reference numeral 21 denotes a power supply cable that supplies high frequency current to the matching transformer 20.

Further, an energizing jig 36 is provided below the matching transformer 20 with respect to the vertically movable table 18 and is movable in the vertical direction and in the direction in which the workpiece 2 moves. That is, the energizing jig 36 includes a holding member 37, a sliding member 34 integral with the holding member 37, and a sliding member 34.
It is directly connected to a hydraulic cylinder 35 as a traveling means via a rod 35a having one end attached to the rod 35a.

The hydraulic cylinder 35 is attached to the suspension member 28 which is raised and lowered by the hydraulic cylinder 27. The hydraulic cylinder 27 is attached to the support plate 23 via connecting members 24, 25, and 26. The support plate 23 is fixed to the vertically movable table 18.

Next, the structure of the contact support device 22 to which the two sets of current-carrying chips 8, 8a are attached will be explained with reference to FIGS. 3A and 3B. This contact support plate 22 is basically already known, for example, from Japanese Utility Model Publication No. 57-24453. Two sets of current-carrying chips 8, 8a, which are provided at positions shifted in the direction of movement of the workpiece 2, are joined to movable blocks 9, 9, respectively. Each movable block 9, 9 is rotatably supported by a hollow shaft 11. The hollow shaft 11 is attached to the support plate 22a. In addition, the opposing current-carrying chips 8a, 8a
The spacing is set to be larger than the spacing between the other pair of opposing current-carrying chips 8, 8.

A connecting pin 14 is provided at the rear of the movable block 9.
A spring support bolt 17 attached to the side surface of the support plate 22a is directly connected through the support plate 22a. That is, the spring support bolt 17 is attached to the L-shaped metal fitting 2 attached to the support plate 22a.
An insulating plate 30 fixed to 9 and an insulating block 31 placed thereon are inserted in the vertical direction.
A spring 32 is inserted into this support bolt 17, and this spring 32 is pressed against the nut 3 via a pressing seat 38.
It is held down by 3.

With the above configuration, the nut 33 is adjusted and the movable block 9 is rotatably supported using the hollow shaft 11 as a fulcrum.
The current-carrying chips 8, 8a move up and down to follow the unevenness of the welding surface, the error in the plate thickness, etc., and are designed so that they do not separate from the workpiece 2 (as mentioned above, this is already known). be). In Fig. 3, reference numeral 40 indicates a cooling water hose, which is connected to a cooling water passage provided in the hollow shaft 11, etc., through which the cooling water circulates to cool each heat generating part during high frequency welding. . Further, in the figure, 22b is a flange of the support plate 22a, and 41 is an insulating plate.

To explain the operation of the above-mentioned ERW pipe welding device, the workpiece 2 transferred by the pinch rolls 3 and 4 is pressurized from both sides by the squeeze roll 6.
The both sides 7, which were separated from each other, are pressed together at this position. On the other hand, the high-frequency current supplied from the power supply cable 21 is transformed by the matching transformer 20, flows from the current-carrying chips 8 and 8a to the workpiece 2, and is broken at the center part A of the line segment connecting the axes of the squeeze rolls 6. The workpiece 2 is then returned and the workpiece 2 is heated and welded.

When the rear end of the work 2 approaches the squeeze roll 6 as shown in FIG. 3 and 4 move in the direction away from work 2,
At the same time, the hydraulic cylinder 27 operates and the energizing jig 36
descends to a position slightly lower than the top surface of the workpiece 2.

Next, a limit switch (not shown) detects that the energizing jig 36 has descended to a predetermined position, the hydraulic cylinder 35 is activated, the energizing jig 36 follows the workpiece 2 at a faster speed than the workpiece 2, and the conductive piece 3
A touch sensor (not shown) detects that the tips of 9 and 39 have come into contact with the inner peripheral surface of the rear end of the workpiece 2, and then the energizing jig 36 is raised several mm and at the same speed as the workpiece 2. It is made to run together with the workpiece 2.

Even when the workpiece 2 is sent out in this state and the energizing chips 8, 8a are removed from the rear end of the workpiece 2, the energizing chips 8, 8a are connected to the energizing jigs 36, 3.
As a result, current can be applied to the workpiece 2 from the current-carrying tips 8 and 8a via the current-carrying piece 39 until the rear end of the workpiece 2 reaches the welding position.

When the rear end of the workpiece 2 crosses the welding position, that is, the line connecting the axes of the squeeze rolls 6 and 6, the energizing jig 36 descends several mm and comes off the workpiece 2, and the hydraulic cylinders 27 and 35 are activated. The energizing jig 36 returns to its original position, and one cycle is completed.

By the way, in this embodiment, the current-carrying chips 8, 8a
The reason why two sets of are provided at a slight interval (for example, about the length of the current-carrying tip) in the direction of movement of the workpiece 2 is as follows. In other words, if there is one set of energizing chips 8, as described in the conventional example (FIG. 4), if there is a step between the energizing jig 36 and the rear end of the workpiece 2, or if there is a gap between them. In such a case, the energizing chip may temporarily float, resulting in poor energization, which may result in welding defects. However,
By providing two sets of current-carrying chips 8, 8a at a predetermined interval in the moving direction of the workpiece 2 and electrically connecting the current-carrying chips on the same side, the current-carrying chip 8 located on the front side as shown in FIG. When the workpiece 2 is transferred from the rear end of the workpiece 2 to the energizing jig 36, even if it temporarily floats on the stepped portion, the rear energizing chip 8a is in contact with the energizing jig 36 at this time, and energization failure may occur. do not have. That is, most of the current normally flows through the current-carrying chip 8, but when the current-carrying chip 8 floats, the current flows through the rear current-carrying chip 8a.

In particular, the current-carrying chips 8, 8a are connected to movable blocks 9, 9, each of which swings freely, as shown in FIG.
are attached to the tips of the springs 32,
32 makes pressurized contact with the workpiece 2, and the distance between the opposing current-carrying chips 8 and 8a is set so that the rear current-carrying chip 8a is larger than the front current-carrying chip 8, so that the contact point with the workpiece 2 is established. By changing the energizing chip 8, one of the two sets of energizing chips 8 and 8a is always in contact with the energizing jig 36, and the workpiece 2 is not energized. The defective problem is completely solved.

Effects of the Invention As described above, according to the present invention, the rear end of the workpiece can be welded without welding a welding auxiliary piece to the workpiece, so work can be carried out efficiently without stopping the flow of the line. Of course, by providing two sets of current-carrying chips along the direction of movement of the workpiece, one of the current-carrying chips temporarily floats at the connection between the rear end of the workpiece and the current-carrying jig. Even if a situation occurs in which the current is not applied due to such reasons, the other energizing chip ensures accurate energization, so that normal welding is always performed and there is no possibility of welding defects, which is an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an electric resistance welding pipe welding device according to an embodiment of the present invention, Fig. 2A is an electrical connection diagram, and Fig. 2B is an explanatory diagram of the state of contact between the energizing chip, the workpiece, and the energizing jig. , FIGS. 3A and 3B are a side view and a half-mounted front view of the contact support device, and FIGS. 4A, B, and C are explanatory diagrams of the state of contact between a conventional energizing chip, a workpiece, and an energizing jig. be. 2... Work (material to be welded), 3, 4, 5... Pinch roll, 8, 8a... Current-carrying chip, 36...
Current-carrying jig, 39... Current-carrying piece.

Claims (1)

[Scope of Claims] 1. A means for feeding a material to be welded formed into a tubular shape with both sides of a plate member facing each other in the axial direction of the material to be welded, a pair of current-carrying chips that are brought into contact with each other in the vicinity and are energized to heat the both sides; a pressurizing means that pressurizes the both sides to weld the electric resistance welding tube; an energizing jig equipped with an energizing piece that extends and energizes the rear end of the welded material by being brought into contact with the energizing chip; and moving the energizing jig into or out of the line of the welded material. In the electric resistance welding pipe welding apparatus, the electric resistance welding pipe welding apparatus is composed of a moving means for moving the energizing jig in the direction of feeding out the workpiece, and a traveling means for moving the energizing jig in the direction in which the workpiece is fed out. An electric resistance welded tube characterized in that another pair of current-carrying chips are provided along the same side and abutted on both sides at a slight interval, and the current-carrying chips on the same side of the both sides are electrically connected to each other. Welding equipment. 2. Among the current-carrying chips, the distance between the current-carrying chips of the pair of current-carrying chips provided on the rear side when viewed from the moving direction of the welding material is larger than the distance between the other pair of current-carrying chips facing each other. An electric resistance welding pipe welding device according to claim 1.