JP2013123728A - Seam welding equipment - Google Patents

Abstract

To provide a seam welding device capable of performing seam welding with the same welding machine even in the case of a workpiece having a sharp bend, such as a frame of an automobile, similarly to a straight portion. In addition, the seam welder itself must be made smaller, and even complex workpieces can be welded smoothly.
A seam welding apparatus that sandwiches a workpiece between two rotating electrodes and continuously energizes the two rotating electrodes to perform resistance welding, and at least one of the rotating electrodes is a cylindrical electrode. Consists of.
[Selection] Figure 2

Description

  The present invention relates to an apparatus for seam welding.

Seam welding and spot welding are known as resistance welding. Of these, spot welding is a welding process in which two plates are stacked, pressed with a rod-shaped electrode (tip), a voltage is applied, and an electric current is applied. This is a welding method in which a part is heated by Joule heat to melt a workpiece locally to join a welding material metallurgically.
Resistance seam welding, on the other hand, uses two disc-shaped welding electrodes, and with continuous workpiece rotation, continuously energizing the current while continuously rotating the workpiece. It is a welding method to be performed.

  In other words, both spot welding and resistance seam welding are resistance welding, but the seam is a continuous stack of spots. Accordingly, the weld strength of the workpiece is higher in seam welding than in spot welding. In addition, it is possible to reduce the material cost of the product because it is possible to withstand tight welding of ultra-thin materials. In addition, there are many advantages in terms of manufacturing costs, such as high-speed welding, which reduces processing costs, and does not require skill in welding technology, which reduces labor costs. Therefore, it is desirable to apply seam welding in a field where improvement of welding quality and suppression of manufacturing cost are desired at a very high level, such as welding of automobile parts. In recent years, a robot-mounted seam welder (for example, see Patent Document 1) and a description that can adjust the angle of the rotation axis of two electrodes have been disclosed (for example, see Patent Document 2). In comparison, it has become possible to handle a variety of workpieces.

  However, since seam welding is performed by sandwiching a workpiece between two disc-shaped electrodes, there is a limit to the shape of the workpiece that can be welded. For example, it is a sharply curved portion (curved portion with a short radius of curvature) of an automobile frame (see FIG. 1). An automobile frame (for example, a door part frame) is formed by forming a butt portion on a stacked plate, sandwiching the butt portion, and preferably performing seam welding (see FIG. 2, and then covering with rubber or the like). Part is made invisible). However, when reaching the sharply bent part, either of the disk-shaped electrodes often hits the main body part, and the electrode cannot be moved along the workpiece, and seam welding is performed on the sharply bent part. I can't. In addition, it is conceivable to reduce the diameter of one of the colliding disks as much as possible. However, even in this case, the feeding portion (the arm portion that feeds power while supporting the disc electrode in rotation operation) has a constant diameter. There is a limit to the diameter of the disk that can be made smaller, and the diameter of the other disk must be increased, so that it will hit the main body, and the problem will not be completely solved. Further, when the diameter is reduced, the electrode is severely worn, resulting in inefficiency such as frequent maintenance.

  Therefore, for workpieces with sharp bends such as automobile frames, seam welding is performed for straight parts and parts with gentle bends, but spot welding is unavoidable for sharp bends. The current situation is.

JP 2007-7777 A JP 2007-167896 A

  Therefore, the present invention provides a seam welding apparatus capable of performing seam welding with the same welding machine, even in the case of a workpiece having a sharp bend, such as an automobile frame. Objective.

In order to achieve the above object, the seam welding apparatus of the present invention is a seam welding apparatus that sandwiches a workpiece between two rotating electrodes and continuously energizes the two rotating electrodes while performing resistance welding. At least one of the rotating electrodes is a cylindrical electrode.
Further, in the seam welding apparatus described above, an angle formed by the rotation axis of one cylindrical electrode and the rotation axis of the other rotation electrode is 90 ° ± 45 ° (however, excluding 90 °). It is preferable that they are arranged as described above.
Further, it is preferable that the other rotating electrode is a disk-shaped electrode.
In addition, it is preferable that the thickness of the portion of the disk-shaped electrode that contacts the workpiece and the thickness of the portion of the cylindrical electrode that contacts the workpiece are the same.
Further, it is preferable that a cooling part having a cooling pipe is built in the cylindrical electrode.
It is also preferable that the robot is mounted on a robot capable of three-dimensional movement.

  As a result of earnest research, the present inventor abandoned the idea of the conventional two disk-shaped electrodes, and at least one of the rotating electrodes was a cylindrical electrode, so that the straight portion and the sharply bent portion were the same seam welder. Welding is possible. Specifically, since the tip of the cylindrical electrode rotates along the welded part so as to cover the cylinder, the electrode can be applied to the sharply bent part as well as the linear part. It is possible. In the present application, the term “cylindrical” means a shape having a hollow portion and capable of seam welding while rotating so as to cover the workpiece, and is necessarily a geometrically perfect cylinder. Does not mean.

  In particular, the advantage of the present invention can be utilized to the maximum by arranging one of the electrodes as a disk-like electrode and arranging the rotation axes of both electrodes at 90 ° ± 45 °, preferably approximately 90 °, not parallel. However, from the viewpoint of meshing with the workpiece, strictly speaking, it is preferable to be slightly shifted from 90 degrees. That is, if the rotation axis of one cylindrical electrode is substantially parallel to the vertical line, the rotation axis of the other disk-shaped electrode is arranged in a direction substantially parallel to the horizontal plane, and the rotation axis of the cylindrical electrode However, by arranging it so that it is on the inner side of the disc-shaped electrode (on the side of the feeding portion of the disc-shaped electrode), it is the same as the linear portion for the sharp bend that has been impossible or very difficult The electrode can be applied to. Therefore, for example, an automobile frame can be welded quickly, which not only contributes to the reduction in manufacturing cost, but also increases the welding strength, thereby increasing the overall strength of the automobile. Furthermore, the seam welder itself can be further downsized. Since the cylindrical electrode can be disposed downward and the other electrode can be disposed laterally, no extra space is required (see FIG. 3). Therefore, especially when it is mounted on a multi-axis welding robot that enables three-dimensional movement, even a workpiece with a complicated shape such as an automobile frame will not get caught anywhere, and welding can be performed smoothly. Is possible.

  Furthermore, according to the above configuration, the cylindrical electrode has no change in the diameter of the circular electrode with respect to the wear of the electrode even though the rotation axes of both electrodes are not parallel. Good maintenance. The other electrode may be a disk-shaped electrode or a cylindrical electrode, but when one is a disk-shaped electrode, the thickness of the disk-shaped electrode is substantially the same as the thickness of the cylindrical wall, The part sandwiching the welding object becomes clearer, the wear part and the ratio are easy to predict, and maintenance is easy.

  As an example of a specific and preferable configuration, a servo motor is provided on a cylindrical electrode housing (power supply unit), and it is possible to press and move up and down via a cylinder / LM guide and the like in a three-dimensional manner. For example, it can be mounted on a multi-axis welding robot that enables movement. The material, diameter, and size of the electrode are appropriately selected according to the target member, as in the case of the disk-shaped electrode of a normal seam welder, and need not be particularly limited.

  Furthermore, since the cylindrical electrode can be provided with a member having a water-cooled tube having an inlet and an outlet inside the cylinder, it is possible to arrange the cooling part closer to the tip, compared to the disk electrode. However, it also has an advantage of high cooling efficiency.

  Since the present invention has the above-described configuration, seam welding can be performed with the same welding machine as in the case of the linear portion even for a workpiece having a sharply curved portion such as an automobile frame. In addition, the seam welder itself can be further miniaturized, even complex workpieces can be welded smoothly, and the maintenance and cooling of the electrodes are easy.

It is a figure showing a part of frame of a car. In the welding of the flame | frame of a motor vehicle, it is a conceptual diagram of the cross section which shows a frame main body, a butting | matching part, and a disk shaped electrode. It is a figure which shows an example of the apparatus for seam welding of this invention. It is a figure which shows an example of the angle of a cylindrical electrode and a disk shaped electrode. It is a figure which shows a cylindrical electrode and a cooling unit.

FIG. 1 is a view showing a part of a frame of an automobile, and the present invention is used for welding a sharp turn 19 of a frame 18. FIG. 2 is a conceptual view of a cross section showing the frame main body 22, the butting portion 21, and the disk-shaped electrode 20 in welding of the frame 18 of the automobile.
FIG. 3 is a view showing an example of the seam welding apparatus 1 of the present invention.
The seam welding apparatus 1 is provided with a cylindrical electrode 2 and a disk-shaped electrode 3, and the tip of the cylindrical electrode 2 and the side surface of the disk-shaped electrode 3 are arranged so as to sandwich the workpiece.
That is, the angle between the rotation axis (not shown) of the cylindrical electrode 2 and the rotation axis (not shown) of the disc-like electrode 3 is arranged in a form close to 90 degrees. Further, the rotation axis of the cylindrical electrode 2 is arranged so as to be on the power feeding unit 4 side of the disk-shaped electrode 3.
That is, when the butted portion 21 is sandwiched, the cylindrical electrode 2 is disposed so as to cover the welded portion from above (see FIGS. 3 and 4), and therefore the sharply bent portion 19 as shown in FIG. Since it can be made to follow with respect to the frame 18 which has, it can weld similarly to a linear part. Note that the angle between the rotation axis (not shown) of the cylindrical electrode 2 and the rotation axis (not shown) of the disc-like electrode 3 does not have to be approximately 90 degrees, and is appropriately set according to the shape of the workpiece. Is. Furthermore, as shown in FIG. 4, since it is slightly shifted from 90 degrees rather than being completely 90 degrees, the workpiece 23 may be easily sandwiched and may be easily meshed. An angle of 90 ° ± 45 ° is preferred.

The cylindrical electrode 2 is pressurized toward the disc-shaped electrode 3 via the servo motor 5, the spline joint 6, the cylinder 7, the LM guide 8, the power feeding unit 10, the housing 13, and the like arranged almost linearly from the top. It is possible to energize while holding the work. On the other hand, the disk-shaped electrode 3 is supported via the power feeding unit 4 and energized. The transformer 11 can supply power to the power supply units 4 and 10, and the torque control motor 9 can control the torque. The support portion 12 is appropriately provided to support each component. . The seam welding apparatus 1 is mounted on a robot 14 (not shown in its entirety), thereby enabling three-dimensional movement.
According to this configuration, as is apparent from FIG. 3, the cylindrical electrode 2 and the disc-shaped electrode 3 are accommodated in a box shape including the power feeding units 4 and 10 and the pressurizing mechanism. Compared to conventional seam welders, there are overwhelmingly less extra space and protrusions. Therefore, the body structure is complicated, such as welding of an automobile frame, and seam welding is possible even in a place where the conventional seam welder cannot be applied because the welder gets caught during welding.

  Further, the wear of the cylindrical electrode 2 appears in a form in which the length of the cylinder decreases, and the diameter of the circle can be maintained, so that maintenance and replacement are not necessary as long as pressure can be applied from above. This is a very important problem when the two disc-shaped electrodes are applied to the workpiece at different rotation axis angles, which is a great advantage.

  Furthermore, as shown in FIG. 5, since the cylindrical electrode 2 has the hollow portion 15, the cooling portion 17 having the water cooling pipe 16 is built in the hollow portion 15, so that the electrode becomes the cooling portion. The contact area can be made larger than that of a general disk-shaped electrode, and further, it has an advantage that it can be configured more easily to cool to the vicinity of the tip. The material of the cooling pipe 16 and the cooling part 17 should just use the material generally used for cooling of the electrode of seam welding. Further, the shape of the cooling pipe 16 and the number of injection / discharge ports are not limited to those shown in FIG. 5, and a plurality of pipes are inserted or a plurality of injection ports and / or discharge ports are provided. Also good.

DESCRIPTION OF SYMBOLS 1 Seam welding apparatus 2 Cylindrical electrode 3 Disc shaped electrode 4 Feed part 5 Servo motor 6 Spline joint 7 Cylinder 8 LM guide 9 Torque control motor 10 Feed part 11 Transformer 12 Support part 13 Housing 14 Robot 15 Hollow part 16 Water cooling pipe 17 Cooling part 18 Automobile frame 19 Steep curve part 20 Disc-shaped electrode 21 Butt part 22 Frame body 23 Workpiece

Claims (8)

  A seam welding apparatus for sandwiching a workpiece between two rotating electrodes and continuously energizing the two rotating electrodes while rotating them to perform resistance welding, wherein at least one rotating electrode is a cylindrical electrode. Seam welding equipment.   2. The seam welding apparatus according to claim 1, wherein an angle formed by a rotation axis of one cylindrical electrode and a rotation axis of the other rotation electrode is 90 degrees ± 45 degrees (excluding 90 degrees). An apparatus for seam welding characterized by being arranged so as to be   3. The seam welding apparatus according to claim 1, wherein the other rotating electrode is a disk-shaped electrode.   4. The seam welding apparatus according to claim 3, wherein the thickness of the portion of the disk electrode that contacts the workpiece is the same as the thickness of the portion of the cylindrical electrode that contacts the workpiece.   The seam welding apparatus according to any one of claims 1 to 4, wherein a cooling part having a cooling pipe is built in the cylindrical electrode.   6. The seam welding apparatus according to claim 1, wherein the seam welding apparatus is mounted on a robot capable of three-dimensional movement.   A cylindrical electrode characterized by being used in a seam welding apparatus that sandwiches a workpiece between two rotating electrodes and continuously energizes the two rotating electrodes while performing resistance welding.   8. The seam welding apparatus according to claim 7, wherein a cooling part having a cooling pipe is built in the cylindrical electrode.

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