JPS632711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of repeatedly using an electrode wire in an electric resistance seam welding method of a side seam portion of a metal can body using an electrode wire.

(Prior Art) Electric resistance seam welding methods using repeated electrode wires are known and are illustrated in FIG. In FIG. 1, A is a polymeric metal plate, 1 is an upper conductive roll 21 is a lower conductive roll, 2 is an upper electrode plate, 22 is a lower electrode plate, 3 is an upper electrode plate drive pulley, 4,
5, 6, 7, 8, 9, 10, 11 are upper guide rolls, 24, 25, 26, 27, 28, 2, respectively.
9, 30, and 31 are lower guide rolls, 12 is a brush for cleaning the upper electrode plate, and 32 is a liquid for cleaning the lower electrode plate, which is located between the upper electrode plate 2 and the lower electrode plate 22 as shown in the figure. The polymerized metal plate A is sandwiched between the two electrode plates 2 and 3, and advances as the two electrode plates move in the same direction, and as it moves between the upper conductive roll 1 and the lower conductive roll 21, the polymerized metal plate A , 21, and are welded by the clamping pressure applied between the two electrodes.

When the upper electrode plate 2 passes through the welding point B, it comes into contact with the metal plate, and the contact portion (surface) becomes dirty (because dirt, oxides, plating metal, etc. on the metal plate surface adhere). After passing through the welding location B, this dirt is cleaned by a rotating cleaning brush 12. or,
The lower electrode plate 22 is cleaned by passing through the cleaning plate 32.

However, whether to use a brush or soak it in a cleaning solution depends on what is attached to the electrode plate, and is not an absolute decision. Both electrode plates 2, 22 are endless annular bands and can be used repeatedly by cleaning them.

However, when this method is used to weld the side seam of a metal can body, the electrode used is a plate, and the width of the seam is usually 0.4 mm or less.
There is a defect in which the electrode plate comes into contact with areas other than the seam, causing current to flow, resulting in unstable welding at the seam.

On the other hand, 2 to 4 times the width of the side seam of the metal can body.
Electric resistance seam welding is known, which is performed using twice the width of the electrode wire. This wire is used with a conductive roll that has a groove on its outer periphery into which the wire fits.

(Problem to be Solved by the Invention) When this wire was used in place of the above-mentioned electrode plate, permanent deformation (elongation) occurred in the electrode wire, and as it was repeatedly used, the width of the wire became wider and the conductive roll It has been found that the wires do not fit into the grooves of the can bodies, and the wires eventually become misaligned with the side seams of the can bodies, resulting in can bodies that cannot be welded.

(Means for Solving the Problems) The present invention makes it possible to use an electrode wire that is permanently deformed at the welding location and to repeatedly use this electrode wire without causing the above-mentioned drawbacks. According to this welding method, after cleaning the electrode surface that has come into contact with the metal can body at the welding point, the electrode surface that has passed through the welding area has changed its cross-sectional shape. An electric resistance seam welding method for can body side seams is obtained, which enables the width of the electrode wire to be formed to a predetermined size and the electrode wire to be used repeatedly.

(Example) An example of the method of the present invention will be explained with reference to FIG.

In FIG. 2, 41 is an upper conductive guide roll (on its outer periphery there is a groove for accommodating and guiding the electrode wire), and 42 is an endless upper electrode wire. 43
is an elongation detection device for preventing the electrode wire 42 from sagging due to elongation occurring at the welding location B, and includes a fixed roll 45,
46, a gauge roll 44 that is located between the fixed rolls 45 and 46 and always receives a pulling force to the right (top of the diagram); a left end position of the gauge roll 44 (top of the diagram);
In other words, a detector 4 detects the position of the object when there is no elongation.
7, and a detector 48 that detects the right end position (on the figure) of the gauge roll 44, that is, the position where the elongation of the electrode wire is maximized in the detection device. 50 is a storage device for storing slack in the electrode wire that has passed through the detection device 43;
6, and a cooperating roller 51' for cooperating with each of these rolls to advance the electrode wire 42,
It consists of 52', 53', 54', 55', and 56'.
60 is a device for measuring the thickness of the electrode wire that has passed through the accommodation device 50; 61 is a substrate for the measurement;
2 is an arm of a measuring device that presses an electrode wire against the substrate 61 and measures the thickness. 70 is a cleaning device, a cutter 71 for scraping the lower surface of the electrode wire;
1, a cutter stand 72 that maintains a predetermined gap between the electrode wire and the cutting edge according to a command from the thickness measuring device 60, a cutter 73 for cutting the upper surface of the electrode wire, and its cutter stand 74. 76 is a metal fitting having a drawing hole for shaping the width of the electrode wire 42, which has passed through the welding point B and has changed its cross-sectional shape, to a constant size; 78 is a metal fitting for performing the drawing and for forming the electrode wire , a main drive roll 77 that feeds the electrode wire toward the conductive guide roll 41 is a rotatable roll that cooperates with the main drive roll 78 to elastically clamp and advance the electrode wire. 80 operates when there is a difference between the speed of the electrode wire advanced by the main drive roll and the speed of the electrode wire advanced by the upper conductive guide roll, detects the difference between both speeds, and adjusts the speed to match both speeds. In the detection device, the gauge roll 8 is located between the fixed rolls 81 and 82 and pulls the electrode wire downward in the figure with a constant pressure.
3. It includes a detector 84 that detects the upper limit position of the gauge roll 83, and a detector 85 that detects the lower limit position. 91, 92, 93, 94, and 95 are rotatable rolls for mere guidance.

In this example device, the upper electrode wire 42 is
Upper conductive guide roll 41, auxiliary drive roll 51,
56 and a main drive roll 78.
First, the electrode wires are stretched as shown in the figure, and the circumferential speeds of the conductive guide roll 41, the auxiliary drive rolls 51, 56, and the main drive roll 78 are set to be equal during the first drive. Note that the auxiliary drive rolls 52, 5
3, 54, and 55 are rotatable. The cross-sectional shape of the electrode wire is a regular square or a rectangle close to it, and it is guided by entering a groove provided around the outer periphery of the conductive guide roll, and a part of the electrode wire is guided through the groove. It protrudes and comes into pressure contact with the side seam of the can body, which is the material to be welded.

The operation of this example device is as follows.

Welding at welding point B takes place almost continuously. Since the wire 42 is heated at this point B by welding heat and current resistance and is also pressurized, permanent elongation (approximately 1 to 2%) occurs. Since the circumferential speeds of the conductive guide roll 41 and the auxiliary drive roll 51 are the same, the elongated electrode wire that is continuously fed out from the welding location is elongated between these rolls. It causes enough deflection. As a result, the gauge roll 44, which is always pulled to the right in the figure, moves to the right from the illustrated position. This moved gauge roll 44 is detected by the detector 4.
8 detects, the detector detects the auxiliary drive roll 5
1 to the continuously variable transmission mechanism (not shown) of the auxiliary drive roll, and
speed up the rotation. Then, the elongation detection device 43
The elongated portion stored in the auxiliary drive roll 51 is transferred between the auxiliary drive rolls 51 and 52 by the auxiliary drive roll 51. As a result, the gauge roll 44
is moved to the left in the figure and detected by the detector 47. When the detector 47 detects this, it issues a command to restore the rotation of the auxiliary drive roll 51, and the rotation of the roll 51 returns to its original state.

The electrode wire is endless, and the thickness and hardness of the electrode wire change as the number of times it passes through the welding point B increases, so the permanent elongation rate of the electrode wire also changes due to changes in the thickness and hardness. Even if this change occurs, a constant tension is always applied to the electrode wire between the conductive guide roll 41 and the auxiliary drive roll 51, so that the electrode wire will not separate from the guide roll.

The electrode wire having a length corresponding to the elongation stored in the elongation detection device 43 is advanced by the fast rotation of the auxiliary drive roll 51.
and 52 as shown in FIG.
form.

At the welding point, the electrode wire is fed out while being continuously permanently elongated, and the gauge roll 44 of the elongation detection device repeats left and right movements, and accordingly the loop 100 becomes longer and its tip lowers. And the loop detector 5 installed below
1'', the loop detector 51'' issues a command to the auxiliary drive roll 52 to rotate the auxiliary drive roll 52 at the same speed as the auxiliary drive roll 51. From then on, both rolls 51 and 52 always rotate at the same speed. Rotate.

Similarly, the loop between the auxiliary drive rolls 52 and 53 is detected by the loop detector 52'', a command is issued, and the auxiliary drive roll 53 is connected to the auxiliary drive roll 51,
It starts rotating at the same speed as 52. This loop formation continues between auxiliary drive rolls 55 and 56 until it is detected by loop detector 55''. If the amount of damage increases to such an extent that it cannot be absorbed by rotating the auxiliary drive roll, the entire device must be stopped, the electrode wire removed, and a new electrode wire inserted.

Now, the electrode wire 42 sent out from the final auxiliary drive roller 56' is then transferred to the thickness measuring device 60.
The thickness is measured. As the electrode wire passes through the welding point, it loses its thickness very slightly and is therefore thinner than when it last passed through the clean point 70. If it is sent as it is to the cleaning device again, and if the position of the cleaning cutter in the device 70 is the same as last time, then after all,
It will not be clean. Thickness measuring device 60
In order to prevent such a situation from occurring, the function is to measure the thickness of the electrode wire in advance and to instruct the cleaning device to change the thickness, and an appropriate method such as optical means or electrode means is selected.

When the cleaning device 70 receives a command from the thickness measuring device 60, the cleaning device 70 performs the following operations on the fixed cutter stands 72 and 74.
The cutters 71, 7 were pressed against the electrode wire passed last time and set in a position where it lightly touches the electrode surface.
3 is the cutter stand 72, 74 by this change in thickness.
Each approaches. Therefore, even if the thickness of the electrode wire is thinner than that of the previous one, the cutter can scrape off the surface of the electrode wire.
For the minute movement of the cutter, well-known means such as a combination of a pulse motor and an eccentric circle can be applied. In the example shown, both sides of the electrode were cleaned by scraping, but
Of course, if the dirt is on only one side of the electrode wire, only one cutter is required.

The cleaned electrode wire is then fed to a pull-out fitting 76 that reshapes its width and is passed to the main drive roll 7.
8 through the fitting.

As mentioned above, at the welding point B, the electrode wire undergoes permanent elongation and its cross-sectional shape changes, so its width also becomes somewhat wider. Even if the pressing force applied to the conductive guide roll 41 is constant, the extent to which it widens is not constant because the hardness of the electrode wire, which is endless and is used repeatedly, changes.

On the other hand, since the width of the electrode wire guide groove on the outer periphery of the conductive guide roll is constant, if the width of the electrode wire is wider than the width of this groove, the wire will not fit into the groove and the electrode wire will be positioned at the side seam of the can body. There is a risk of it coming off. The width of the electrode wire must therefore always be slightly narrower than the width of the groove in the conductive guide roll. The extraction fitting 76 is provided for this purpose, and has the role of keeping the width of the electrode wire constant at all times. This extraction fitting only limits the width, and has a sufficient margin in the thickness direction than the initial electrode wire thickness.

The electrode wire that has passed through the extraction fitting 76 is elastically pressed between rolls 78 and 77, and both sides of the electrode wire in the thickness direction are prepared.

The cleaning point 70 and the extraction point 76 are preferably provided with a compressed air blowing device and an air suction device for removing chips.

The electrode wire sent out from the main drive roll is
It passes through the speed detection device 80 and returns to the conductive guide roll 41. This speed detection device 80 is a device for preventing an increase in current resistance that occurs when there is a gap between the electrode wire and the conductive guide roll. A constant tension is applied to the electrode wire between the drive roll and the conductive guide roll to force the electrode wire firmly against the bottom surface of the groove of the conductive guide roll and to enable winding of the electrode wire around the conductive guide roll. The moving roll 83 of this detection device 80 normally moves the upper detector 8
4 and the lower detector 85, and when the position of the movable roll 83 moves, the rotation speed of the main drive roll 78 and the auxiliary drive roll 56 are determined based on the commands detected by the upper and lower detectors. The number of rotations of the moving roll 83 is returned to the center position by equally increasing and decreasing the number of rotations of the moving roll 83, so that the tension can always be applied within a certain range.

Since the main drive roll 78 and the auxiliary drive roll 56 are changed at the same speed at the same time, the electrode wire between the two rolls does not become slack or break.

In the above specific example, the electrode wire is endless and can be used repeatedly, but the electrode wire is wound on a reel in advance, and as it is unwound, it is placed in the groove of the conductive guide roll and advanced. The method of the present invention can also be applied to the case where the electrode wire that has progressed is wound on another reel and the wound electrode wire is reused.

When using this winding reel, an electrode wire is inserted between the main drive rolls 78 and 77 of the device example shown in FIG. All you have to do is change it to a reel and wind it up. After winding it up, measure the thickness of the electrode wire, determine the distance between the cutter of the cleaning device and the cutter stand, fix the cutter, pass the electrode wire through, and then pull it out. All you have to do is pass it through the metal fittings and wind it onto another reel.

In FIG. 2, the device related to the lower conductive guide roll 41 is the same as the device related to the upper conductive guide roll 41, and the number indicating the device related to the upper conductive guide roll plus 100 is used to indicate the upper conductive guide roll of the lower conductive guide roll. A device corresponding to a device related to guide rolls is shown. For example, the main drive roll is 17
8,177, and the lower electrode wire is like 142. However, it is clear from the above that it is not always necessary to have two upper and lower electrode wires, and that one electrode wire is also possible.

Further, as a cleaning device, an example of removing the electrode wire with a cutter has been shown, but depending on the dirt or deposits on the electrode wire, a device that soaks the electrode wire in a chemical solution to dissolve it may be used.

(Effects of the Invention) The present invention provides the following advantages when repeatedly using an electrode wire:
In addition to cleaning the surface of the electrode wire in contact with the metal can body, the width of the electrode wire is formed to a predetermined size, so the wire width is expanded due to permanent elongation when the electrode wire passes through the welding point. No matter how many times the electrode wire is used, the electrode wire will remain in the groove, and the electrode will be able to accurately contact the side seam of the metal can body for reliable welding.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a known electric resistance seam welding method, and FIG. 2 is an explanatory diagram of an example of the electric resistance seam welding method of the present invention. In the figure, A...Polymerized metal plate, B...Welding location, 1...Upper conductive roll, 21...Lower conductive roll, 2, 22
... Electrode plate, 41 ... Upper conductive guide roll, 141 ...
Lower conductive guide roll, 42... Upper electrode wire, 1
42... Lower electrode wire, 43, 143... Electrode wire elongation detection device, 50, 150... Electrode wire slack accommodation device, 60, 160... Electrode wire thickness measuring device, 70, 170... Electrode wire cleaning device, 80 , 180...electrode wire speed detection device.

Claims (1)

[Scope of Claims] 1. In an electric resistance seam welding method for a side seam of a metal can body using an electrode wire having a square cross section that causes permanent deformation at the welding location, A can body side characterized in that after cleaning the contact surface with the metal can body, the width of the electrode wire whose cross-sectional shape has changed by passing through the welding point is formed into a predetermined size, and the electrode wire is used repeatedly. Electric resistance seam welding method for seams.