JPH05304Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spot welding device, and more specifically, for example, in the spot welding process of an automobile body, in particular, it is used to join workpieces having a bag-like closed curved surface. This invention relates to a spot welding device suitable for welding work.

[Background of the invention] For example, when assembling the body of an automobile, thin plate materials as workpieces are joined by spot welding. This spot welding work is carried out by applying welding current to the joint while pressing the workpiece with the electrodes of a resistance welding gun.

Incidentally, the workpieces used for assembling automobile bodies are wide-ranging, from planar objects such as body outer panels to objects exhibiting three-dimensional shapes. Examples of three-dimensional workpieces include those that have a bag-like or approximately cylindrical shape, such as an oil cap.

Therefore, FIG. 1 shows an example of a bag-shaped workpiece. In the figure, reference numeral W ₁ is a bag-shaped workpiece having a closed curved surface at one end, and reference numeral W ₂ is a flat workpiece to which this workpiece W ₁ is joined. In joining the work W ₁ and the work W ₂ ,
Consider P ₁ , P ₂ , P ₃ . . . as the joint points.
Conventionally, the resistance welding gun was first spot-welded at joint point _P1 , then the resistance welding gun was rotated by a predetermined angle, and the next joint point _P2 was spot-welded. The work is done by rotating the welding gun. However, in such welding work, it is difficult to shorten the welding time for one workpiece, and there is a disadvantage that the work efficiency is not improved much. Therefore, improvement is desired.

[Purpose of the invention] The present invention was devised to overcome the above-mentioned disadvantages, and includes supporting a bag-shaped workpiece from its outer surface with electrodes, and pressing the workpiece from its inner surface with a plurality of electrodes. By applying welding current, spot welding can be performed at multiple locations at once, and by making the welding gun body rotatable to change the welding point, work efficiency is greatly improved. The purpose of the present invention is to provide a spot welding device that can perform spot welding.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention is a spot welding device for joining bag-shaped workpieces with one end open by spot welding, which a welding gun having a support means having a workpiece receiving electrode that holds the workpiece from the outer circumferential surface, a pair of rotatable gun arms having electrode tips disposed at the tips thereof so as to face the workpiece receiving electrode; The welding gun is characterized by comprising an actuator that opens and closes the gun arms so as to approach and separate them from each other, and a rotation drive means that rotates the welding gun itself by a predetermined angle along the axial direction of the gun arm.

[Embodiments] Next, preferred embodiments of the spot welding apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 20 designates a spot welding device according to the present invention. This spot welding device 20 includes a workpiece support mechanism 22 as a means for supporting a bag-shaped workpiece _W1 having an open end at one end and a closed curved surface at the other end from its outer peripheral surface, and
It basically consists of a spot welding mechanism section 24 that presses a workpiece _W2 against _W1 using, for example, two electrodes and applies current to the welding portion of the workpieces _W1 and _W2 .

First, the workpiece support mechanism section 22 includes a first support arm 26 erected on a base (not shown), and a second support arm 26 that is swingably connected to the tip of the first support arm 26 via a pin 28. and a support arm 30. A cylinder 34 as a drive source for swinging the second support arm 30 is disposed at a predetermined portion of the first support arm 26 via a bracket 32. In this case, a connecting member 38 is provided at the tip of the pinton rod 36 extending from the cylinder 34.
is attached, and this connecting member 38 is connected to a lever 4 fixed to the second support arm 30 via a pin 40.
2 is connected. Therefore, by biasing the cylinder 34 and moving the piston rod 36 forward and backward in the vertical direction, the second support arm 30 is configured to be freely rotatable about the pin 28. In this case, the cylinder 34 is supported by a pin 44 so as to be slightly rotatable relative to the bracket 32 fixed to the first support arm 26, thereby allowing the second support arm 30 to rotate. is carried out smoothly.

The second support arm 30 is bent in a horizontal direction substantially at its distal end, and a holding member 46 is fixed to this distal end. The configured work receiving electrode 50 is fixed. The workpiece receiving electrode 50 is largely curved into a C-shape in order to receive the bag-shaped workpiece _W1 . moreover,
This workpiece receiving electrode 50 is shown in FIG.
As can be understood from the line sectional view), it is a substantially hollow member, and holding members 52a and 52b for holding the workpiece _W1 from both sides are installed inside the member, and both ends of the member are opposed to each other. work at
I firmly support W ₁ .

Next, the spot welding mechanism section 24 will be explained.

This spot welding mechanism section 24 is connected to the workpiece support mechanism section 22 via a mounting plate 54 fixed to the lower end of the first support arm 26 of the workpiece support mechanism section 22.
A welding gun 58 is provided integrally with the workpiece receiving electrode 50 and facing the work receiving electrode 50, and is disposed on the turn plate 56 as a machine base.
and a rotation mechanism section 60 that rotates the welding gun 58.
It basically consists of.

First, the support shaft 62 that is integral with the turn plate 56 is attached to the housing 6 fixed to the mounting plate 54.
4, it is rotatably supported via rolling bearings 66a, 66b. On the other hand, the turn plate 56 is connected to a cylinder 68 as a rotational drive source. That is, as shown in FIG. 4, the piston rod 70 of the cylinder 68 is connected to the link piece 7.
2 to a connecting lever 74 fixed to one end of the turn plate 56. In the turn plate 56, the connecting lever 74
An abutting member 76 is fixed near the connecting lever 74, and the abutting member 76 can freely come into contact with the connecting lever 74. A stopper 78 for regulating the rotation angle of the turn plate 56 is provided at a predetermined portion of the mounting plate 54.

In this way, the welding gun 58 is attached to the turn plate 56 which is configured to be rotatable. That is, a first gun arm 84a and a second gun arm 84b are rotatably supported by brackets 80a and 80 fixed to the turn plate 56 via pins 82. In this case, the first gun arm 84a is provided with a cylinder 86 as a driving source for opening and closing the first gun arm 84a and the second gun arm 84b, and the pin 90 engaged with the piston rod 88 of the cylinder 86 is connected to the second gun arm 84a. It engages with a long hole 92 drilled in 84b. Also,
Stopper pins 94a and 94b are attached to the first gun arm 84a and the second gun arm 84b, and when the tips of these stopper pins 94a and 94b abut against a contact piece 96 provided between the brackets 80a and 80b, the first gun arm 84a and the second gun arm 84b from contacting each other and causing an electrical short circuit.

On the other hand, electrode holders 98a and 98b are fixed to the first gun arm 84a and the second gun arm 84b, respectively, and cables are connected to the electrode holders 98a and 98b by terminals not shown.
Electrode chips 100a and 100b are attached to the tip portions thereof. In this case, each electrode chip 1
00a and 100b are directions opposite to each other, that is, the first gun arm 84a and the second gun arm 84.
b are mounted so that they are oriented in a direction that separates them from each other.

The stopper welding device according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

First, in Fig. 2, work W ₁ and work W ₂
is transported to a predetermined position by a transport means while being integrally supported by a holding member for inserting a workpiece (not shown). At that time, the spot welding device 20
In the case of the work support mechanism section 22, the cylinder 3
The piston rod 36 of No. 4 is retracted as shown by the two-dot chain line in the figure, and therefore, the second support arm 30 at the tip of the first support arm 26 is tilted to the position shown by the two-dot chain line. It is in.

Therefore, after the workpieces W ₁ and W ₂ are set at predetermined positions, the entire spot welding apparatus 20 is displaced so that the welding gun 58 of the spot welding mechanism section 24 faces the workpiece W ₁ . Then, when the cylinder 34 in the workpiece support mechanism section 22 is energized to extend the piston rod 36, the second support arm 30 rotates in the direction of arrow A about the pin ₂₈ , and the second The workpiece receiving electrode 50 at the tip of the support arm 30 holds the outer peripheral surface of the workpiece _W1 .

Next, in the welding gun 58, the first gun arm 84a and the second gun arm 84b are opened to press the welding points of the works _W2 and _W1 with the electrode tips 100a and 100b. That is, if the cylinder 86 provided on the first gun arm 84a is urged to extend the piston rod 88 in the direction of the arrow,
The second gun arm 84b that engages with the piston rod 88 rotates in the opening direction, and the electrode tip 100b attached to the electrode holder 98b at the tip of the second gun arm 84b comes into contact with the workpiece _W2 .
Press W ₁ and W ₂ toward the work receiving electrode 50 side. At this time, the reaction force moves the first gun arm 84a to the second gun arm 84a.
An electrode chip 10 is attached to the tip of the first gun arm 84a via an electrode holder 98a in order to be displaced in a direction away from the gun arm 84b.
0a contacts the workpiece W ₁ and presses the workpieces W ₁ and W ₂ against the workpiece receiving electrode 50 .

Therefore, when a welding current of a predetermined magnitude is applied, the current flows from the electrode tip 100a to the work W ₁ ,
_The workpiece W ₁ and the workpiece W ₂ are welded together by the Joule heat generated at that time. When the cylinder 86 is deenergized and the piston rod 88 is retreated after the welding process is completed, the pressing state by the electrode tips 100a, 100b is released, and the electrode tips 100a, 100b are separated from the workpiece _W1. . In this way, according to the present invention, two welding points can be welded at once.

Next, in the rotation mechanism section 60, the cylinder 68 is energized to rotate the welding gun 58 to change the welding point. That is, as shown in FIG. 4, when the piston rod 70 of the cylinder 68 is retreated, the piston rod 70 and the link piece 7
The turn plate 56 is integral with the connecting lever 74 connected via the connecting lever 74 and is rotatably supported by the support shaft 62.
Rotate until it touches the. In FIG. 2, a bracket 80 integral with the turn plate 56 is shown.
The first gun arm 84a and the second gun arm 84b attached to the electrodes 100a and 80b rotate by a predetermined angle about the support shaft 62, and as shown in FIG. It will be displaced from the position to the position shown by the solid line. Then, at this welding point, the first gun arm 84a and the second gun arm 84b are rotated in the direction of separating them using the same device as described above, and the electrode tips 100a and 100b are used to separate the workpiece W ₁ and the workpiece.
Spot welding is performed by applying welding current while pressing W ₂ toward the work receiving electrode 50 side.

After that, the cylinder 86 is deenergized and the first gun arm 84a and the second gun arm 84b are rotated in the closing direction to separate the electrode chips 100a and 100b from the workpiece _W1 , and the cylinder 34 is moved in the workpiece support mechanism section 22. By retracting, the second support arm 30 is rotated to the position shown by the two-dot chain line. Joined workpiece W ₁ ,
W ₂ is delivered to the next step by a transport means (not shown).

In this way, as new workpieces are conveyed one after another, the spot welding work is continuously performed using the spot welding apparatus 10.

[Effects of the invention] As described above, according to the invention, a bag-shaped workpiece is supported from the back by a workpiece receiving electrode, a welding gun is brought into the welding point of the workpiece, and the welding point is pressed by two electrode tips. However, after spot welding two points at the same time, the welding gun itself is rotated to immediately change the position of the electrode tip to the next welding point, so that welding can be performed again. Therefore, it is possible to weld at least two locations at the same time and to quickly change the welding points. Therefore, the welding time per work piece can be significantly shortened, and the efficiency of spot welding work can be improved.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to this embodiment.
It goes without saying that various improvements and changes in design are possible without departing from the gist of the present invention, such as the possibility of further increasing the number of electrode chips.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view of the shape of a bag-like workpiece to be used in a spot welding device according to the present invention, FIG. 2 is a partially sectional side view of the spot welding device according to the present invention, and FIG. FIG. 4 is a sectional view taken along the - line in the figure, and FIG. 4 is an explanatory diagram of the configuration of the rotation mechanism section of the spot welding apparatus as seen from the - line in FIG. 2. 20... spot welding device, 24... spot welding mechanism section, 26, 30... support arm, 46...
... Holding member, 48 ... Insulating member, 50 ... Work receiving electrode, 56 ... Turn plate, 58 ... Welding gun, 60 ... Rotating mechanism section, 62 ... Support shaft, 68
...Cylinder, 84a, 84b...Gun arm,
86... Cylinder, 98a, 98b... Electrode holder, 100a, 100b... Electrode chip, W ₁ ,
W ₂ ……Work.

Claims (1)

[Scope of utility model registration request] A spot welding device for joining bag-shaped workpieces with one end open by spot welding, the apparatus comprising a support means having a workpiece receiving electrode for holding the bag-shaped workpieces from the outer peripheral surface of the bag-shaped workpieces, and a pair of rotatable workpieces. a welding gun having an electrode tip disposed at the tip of a gun arm so as to face the work receiving electrode; an actuator for driving the pair of gun arms to open and close so as to approach and separate from each other; What is claimed is: 1. A spot welding device comprising: rotational drive means for rotating a spot welding device by a predetermined angle along a direction.