JPH0644521Y2 - Roll spot welder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention holds a workpiece by a pair of electrodes, pressurizes,
The present invention relates to an improvement of a roll spot welding machine that performs roll spot welding while energizing electricity.

(Prior Art) A conventionally used roll spot welding machine will be described with reference to FIG. In the figure, 1 indicates a roll spot welder body, and 2 and 3 indicate a roll spot welder body 1
2 shows a pair of rotating electrodes provided in the. One rotating electrode 2 of the pair of rotating electrodes 2 and 3 (hereinafter referred to as one electrode 2) is rotatably fitted to the electrode head 4, and the other rotating electrode 3 (hereinafter referred to as the other electrode 3). Is rotatably fitted to the electrode head 5.

The electrode head 4 is connected to a piston rod 6a of a cylinder mechanism 6 (hereinafter referred to as a cylinder) provided on the upper part of the roll spot welding machine body 1 via a link 7, and the electrode heads 5 are provided on both sides of the electrode head 5. It is fixedly supported on the lower end of a provided bracket (not shown). Roll spot welder body 1 equipped with this pair of electrodes 2 and 3
Is attached to the robot arm 8 so that it can be moved. In the figure, W indicates an object to be welded.

When such a roll spot welding machine welds the workpiece W, the robot arm 8 moves the pair of electrodes 2 and 3 to operate the rod 6a of the cylinder 6 at the welding start point of the workpiece W. Then, the welding points are clamped, and electricity is applied to perform welding.

(Problems to be Solved by the Invention) However, in the above-described conventional roll spot welding machine, when welding is repeatedly performed, the pair of electrodes gradually wears and the other electrode is fixed, so The pressure point by the electrode of is gradually deviated from the one electrode toward the other electrode, and if welding is continued as it is, only one electrode of the pair of electrodes abuts the workpiece,
There has been a problem that the object to be welded is deformed to cause a welding defect. In addition, the pressure of the pressure cylinder is linked via a link.
Since it is transmitted to the electrodes, there is a problem in that the pressure applied to the electrodes is dispersed.

Therefore, what has been devised to improve this has already been proposed (Japanese Patent Application No. 63-246554). As shown in FIG. 6, the proposed roll spot welding machine is a bracket that supports an electrode head 11 having one electrode 9 of a pair of electrodes 9 and 10.
12 is connected to the piston rod 13a of the cylinder 13, and the base end 12a of the bracket 12 is slid on a pair of rails 15 (only one rail 15 is shown in FIG. 6) fixed to the robot arm 14. A bracket that movably supports the electrode head 16 having the other electrode 10
17 and the bracket 17
The base end portion 17a of the above is slidably supported by a pair of rails 15.

With this configuration, when the pair of electrodes 9 and 10 are moved by the robot arm 14 to the position where the workpiece W is clamped, the piston rod 13a of the cylinder 13 is extended and one of the electrodes 9 is railed. The electrode 9 is moved downward along 15 to bring one electrode 9 into contact with the workpiece W. At this time, since the other electrode 10 moves upward due to the reaction force,
The workpiece W is strongly sandwiched by the pair of electrodes 9 and 10.

However, when the pair of electrodes 9, 10 clamps the workpiece W, the other electrode 10 rises due to the reaction force associated with the lowering of the one electrode 9 to clamp the workpiece W strongly. However, when sandwiched, the workpiece W is subjected to the load of the pair of electrodes 9 and 10 and its accessory device, and the workpiece W is deformed, resulting in poor welding.

(Means for Solving the Problems) As a means for solving the above problems, the present invention rotatably mounts a pair of electrodes on a body of a roll spot welding machine mounted on a robot arm, and connects the pair of electrodes between the pair of electrodes. In a roll spot welder for sandwiching an object to be welded and guiding the robot arm along a welding line of the object to be welded by applying current and pressure to perform roll spot welding, the robot arm is provided with the roll spot welder main body. Of the pair of electrodes is slidably supported on the base, and one electrode of the pair of electrodes is attached to a piston rod of one cylinder device provided in the roll spot welding machine body. Along with the connection, the other electrode is connected to the main body of the cylinder device, and the base is provided with movement amount suppressing means for suppressing the movement amount of the pair of electrodes in the separating direction. , The lower electrode of the other electrode is engaged with the base, and a force substantially equal to the load of the pair of electrodes and one cylinder device added to the workpiece is applied to the other electrode. It is characterized in that a resilient urging means having a support plate attached to the upper portion is provided, which is added in a direction opposite to the direction and holds the position of sandwiching the welding line of the object to be welded of the pair of electrodes. It is a thing.

(Operation) Since the present invention is configured as described above, when the pair of electrodes is moved to a position where the workpiece is clamped, the piston rod of the cylinder device provided in the body of the roll spot welder is shortened, and the pair of electrodes is shortened. The electrode is brought into contact with the movement amount suppressing means provided on the base to lock the electrode in the released state. By moving the pair of electrodes in this state, it becomes possible to quickly move the pair of electrodes to a position where the welding line of the workpiece is clamped in an extremely stable state. Next, the cylinder is operated to extend the piston rod and hold the object to be welded by the pair of electrodes.

When the pair of electrodes sandwiches the object to be welded, a load such as the pair of electrodes and one cylinder device is applied to the object to be welded. For this reason, the base is engaged with the lower portion of the other electrode, and a force almost equal to the load of the pair of electrodes and one cylinder device added to the workpiece is applied to the other electrode in the direction of the load. It is added in the opposite direction to the position where the welding line of the objects to be welded of the pair of electrodes is held. Since the elastic urging means having the support plate attached to the upper part is provided, the elastic urging means enables the pair of electrodes to clamp the welding line of the object to be welded at a normal position. Therefore,
The object to be welded is sandwiched by a pair of electrodes from above and below with equal electrode pressing force.

When the pair of electrodes sandwiches the object to be welded at the position of the normal welding line, the robot arm guides the roll spot welding machine body to energize and pressurize to perform predetermined roll spot welding.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. In the figure, 18 indicates a roll spot welding machine main body, and 19 and 20 indicate a pair of electrodes provided on the roll spot welding machine main body 18. Reference numeral 21 denotes an upper electrode head, and 22 denotes a power supply shaft having one electrode 19 of the pair of electrodes 19 and 20 attached to the tip. The power supply shaft 22 is rotatably fitted to the electrode head 21. Power supply shaft 22
A power supply block (not shown) for supplying a welding current and a welding transformer (not shown) are connected to the.

Reference numeral 23 denotes a lower electrode head, and reference numeral 24 denotes a power feeding shaft having the other electrode 20 of the pair of electrodes 19 and 20 attached to the tip. The power supply shaft 24 is rotatably fitted to the electrode head 23. A power supply block (not shown) and a welding transformer (not shown) for supplying a welding current are connected to the power supply shaft 24.

Then, on both sides of the electrode heads 21, 23, support brackets 25,
25 are arranged. The support brackets 25, 25 support the lower electrode head 23 from both side surfaces, and the upper end of the support brackets 25, 25 is a cylinder device 26 provided in the roll spot welding machine body 1.
Is stuck to the body of. Therefore, the other electrode 20 is connected to the main body side of the cylinder device 26.

In addition, the support bracket 2 is also provided inside the support brackets 25, 25.
7,27 are arranged. The support brackets 27, 27 support the upper electrode head 21 from both side surfaces, and the upper ends thereof are fixed to the piston rod 26a of the cylinder device 26. Therefore, one electrode 19 is connected to the piston rod 26a of the cylinder device 26, and if the piston rod 26a of the cylinder device 26 expands and contracts, one electrode 1
9 moves up and down in FIG.

A pair of bearings 28, 28 are fixed to the base end portions 25a, 25a of the support brackets 25, 25, respectively.
A pair of bearings 29, 29 is fixed to the base end portions 27a, 27a of the 27. The pair of bearings 28, 28 and the pair of bearings 29, 29 are slidably fitted to a pair of rails 32, 33 provided on a base 31 fixed to the robot arm 30.
Therefore, the pair of electrodes 19 and 20 are slidably supported by the base 31 fixed to the robot arm 30.

Then, stopper brackets 34, 34 are fixed to the upper and lower portions of the rail 32 on one side, and the stopper brackets 34, 34 have movement amount control means for suppressing the movement amount of the pair of electrodes 19, 20 in the separating direction. Stoppers 35, 35 are provided. Note that the lower stopper bracket 34 and the stopper 35 show a support plate 45 described later, so that the illustration is omitted.

That is, the stoppers 35, 35 suppress the movement amount of the bearing 28 of the support bracket 25 supporting the lower electrode head 23 and the bearing 29 of the bracket 27 supporting the upper electrode head 21 on the rail 32 on one side. ing. As a result, the amount of movement of the pair of electrodes 19, 20 is suppressed.

Reference numeral 36 denotes a bracket fixed to the lower part of the pair of rails 32, 33 of the base 31 on one rail 32 side, and 37 denotes a pipe-shaped spring support column fixed to the bottom portion 38 of the bracket 36. Further, 39 is a washer arranged below the spring support column 37, and 40 is a U-shaped metal fitting whose both ends are fixed to the washer 39. A through hole 41 is formed in the closed portion of the U-shaped metal fitting 40.

The through hole 41 and the screw hole 42 formed in the bottom portion 38 of the bracket 36
An adjusting bolt 43 for adjusting the elastic force of a spring 47, which will be described later, is provided on the. Reference numeral 44 indicates a lock nut. In addition, the base of the support bracket 25 is provided below the base end portion 25a (on the left side in FIG. 3) of one of the pair of bearings 28.28 of the support brackets 25, 25 supporting the lower electrode head 23. A support plate 45 that engages with the end portion 25a is attached to the bracket 36, and a spring 47 described later is used.
It is provided through.

The support pillars 46 are fixed to the support plate 45.
Reference numeral 46 is slidably fitted into a pipe-shaped spring support column 37. Reference numeral 47 denotes a spring which is an elastic urging means for holding a position where the welding line of the workpiece W of the pair of electrodes 19 and 20 interposed between the washer 39 and the support plate 45 is held. The support plate 45 is constantly elastically urged upward.

The elastic force of the spring 47 is adjusted by the adjusting bolt 43 so as to be substantially equal to the load of the pair of electrodes 19 and 20 supported by the base 31, the one cylinder device 26, and the like. When adjusting the elastic force of the spring 47, if the working fluid inside the cylinder device 26 is released, one electrode 19 descends by its own weight and contacts the other electrode 20,
In this state, loosen the lock nut 44, and adjust bolt 43
Thus, the pair of electrodes 19, 20 is raised to a position where the welding line of the workpiece W is clamped, and the lock nut 44 is tightened to lock the adjustment bolt 43. Therefore, the other electrode 20 is applied by the spring 47 in a direction opposite to the load direction with a force that makes the load substantially equal to the load of the pair of electrodes 19, 20 and one cylinder device or the like.

The operation of the roll spot welding machine configured as described above will be described. Before welding, the piston rod 26a of the cylinder device 26 of the roll spot welder main body 18 attached to the robot arm 30 is shortened, and the pair of electrodes 19, 20 is in an open state.

In this state, the bearings 28 and 29 sliding on the rail 32 on one side are in contact with the stoppers 35 and 35 (the lower side is not shown), respectively. That is, the pair of electrodes 19, 20 is locked in the opened state in cooperation with the stoppers 35, 35 by shortening the piston rod 26a of the cylinder device 26, and the pair of bearings 28, 28 and 29,
A pair of electrodes 19, 20 and one cylinder device 26, which are supported by 29, for example, the upper electrode head 2
1, lower electrode head 23, support brackets 25, 25 and 2
All loads of 7,27 are transferred to the base 31 via a pair of rails 32,33.
Supported by.

During welding, the robot arm 30 operates and the pair of electrodes 19, 20 of the roll spot welder main body 18 moves to a position where the welding line of the workpiece W is sandwiched.

Next, the cylinder device 26 operates to extend the piston rod 26a. Then, one electrode 19 of the pair of electrodes 19, 20 descends and abuts on the welding line of the workpiece W. Due to the reaction force generated at this time, the other electrode 20 of the pair of electrodes 19, 20 rises, and the welding line of the workpiece W is sandwiched by the pair of electrodes 19, 20.

When the welding line of the workpiece W is sandwiched by the pair of electrodes 19 and 20, the robot arm 30 guides the roll spot welder main body 18 along the welding line of the workpiece W and energizes and pressurizes the welding spot. Predetermined roll spot welding is performed.
When all the predetermined roll spot welding is completed, the piston rod 26a of the cylinder device 26 is shortened and the one electrode 19 is raised. Along with this, the bearing 29 sliding on the rail 32 on one side also rises and abuts on the stopper 35 on the upper side. Due to the reaction force generated at this time, the other electrode 20 descends, the bearing 28 sliding on the rail 32 on one side also descends, and abuts on the stopper 35 (not shown) on the lower side. Therefore, the pair of electrodes 19, 20 returns to a predetermined position by shortening the piston rod 26a of the cylinder device 26, and the stoppers 35, 35
It will be unlocked in collaboration with. Pair of electrodes 1
When the electrodes 9 and 20 are opened, the pair of electrodes 19 and 20 release the welding line of the workpiece W, the roll spot welder main body 18 is returned to the original position by the robot arm 30, and one cycle is completed.

When welding, that is, when the welding line of the workpiece W is sandwiched between the pair of electrodes 19,20, the pair of bearings 28,28 and the pair of bearings 29,29 are accompanied by the movement of the pair of electrodes 19,20. Also moves up and down. And one rail 3
The one bearing 28 and the one bearing 29 fitted to 2 (left side in FIG. 3) are separated from the stoppers 35, 35 to clamp the object to be welded.

When the pair of electrodes 19 and 20 sandwich the workpiece, the workpiece W
A load supported by the base 31 is added to the bearings 28 and 29, which is supported by the bearings 28 and 29, that is, via the rails 32 and 33. But the lower electrode head
A pair of bearings 2 of support brackets 25, 25 supporting 23
In the lower part of the base end portion 25a of one of the bearings 8 and 28 on the side of the bearing 28,
A support plate 45 with a spring 47 interposed is provided, and the support plate 45
Is always elastically urged by the spring 47, so the pair of electrodes 1 supported by the base 31 via the rails 32, 33
The loads of 9, 20 and one cylinder device 26 are supported by the support plate 45. That is, the welding line of the object to be welded W is sandwiched by the pair of electrodes 19, 20 from above and below with the same electrode pressing force. Therefore, a load supported by the base 31 is not applied to the sandwiching portion of the object to be welded W, and the object to be welded W is not deformed and welding failure does not occur.

(Effects of the Invention) As described in detail above, the present invention shortens the piston rod of the cylinder device when moving the pair of electrodes to the position where the workpiece is held, and moves the pair of electrodes on the base. The pair of electrodes is moved to the position where the welding line of the workpiece is clamped in an extremely stable state because the pair of electrodes are locked in the open state and moved by contacting the quantity suppressing means. Can be made. Also, when moving, the pair of electrodes is always locked in an open state, so even if the pair of electrodes approaches the workpiece,
Since the electrode does not contact the object to be welded, it is possible to prevent the object to be welded and the electrode from being damaged.

Further, a force that is engaged with the lower part of the other of the pair of electrodes and is approximately equal to the load applied to the workpiece is applied in a direction opposite to the direction of the load applied to the other electrode, and Since the elastic biasing means for holding the position where the welding line of the welded object is held is provided, the pair of electrodes can hold the welding line of the welded object at a normal position by this elastic biasing means. it can.
As a result, only the electrode pressing force of the cylinder device is applied to the welding line from above and below, and it is possible to avoid the welding object from being deformed without applying an excessive load to the welding object. . Therefore, good roll spot welding can be performed, and the quality of roll spot welding can be improved.

Further, since the elastic urging means having the support plate attached to the upper portion provided on the base is designed to support the load of the pair of electrodes and one cylinder device by the support plate, it can be stably supported. In addition, it is not necessary to attach any parts to the pair of electrodes and one cylinder device, and the present welding machine can be easily manufactured by slightly improving the conventional roll spot welding machine. Since the roll spot welding machine thus constructed has a simple structure and is formed compactly, it has many effects such as a low manufacturing cost, easy maintenance work, and low maintenance cost.

[Brief description of drawings]

FIG. 1 is a left side view of a roll spot welding machine main body showing an embodiment of the present invention, FIG. 2 is a right side view of that of FIG. 1, FIG. 3 is a front view of that of FIG. 1, and FIG. FIG. 4 is an enlarged view of the IV portion of FIG. 3, and FIGS. 5 and 6 are right side views of the conventional roll spot welding machine main body. 18 …… Roll spot welding machine body 19 …… One electrode 20 …… Other electrode 26 …… Cylinder device 26a …… Piston rod 30 …… Robot arm 31 …… Base 35 …… Stopper 45 …… Support plate 47… … Spring W …… Workpiece to be welded

Claims (1)

[Scope of utility model registration request] 1. A pair of electrodes is rotatably attached to a roll spot welding machine main body attached to a robot arm, an object to be welded is sandwiched between the pair of electrodes, and a welding line of the object to be welded is provided by the robot arm. In a roll spot welding machine that performs roll spot welding by energizing and pressing while guiding along, the base of the roll spot welding machine main body is fixed to the robot arm, and the pair of electrodes is slidably supported on the base. One electrode of the pair of electrodes is connected to the piston rod of one cylinder device provided in the roll spot welding machine main body, and the other electrode is connected to the main body of the cylinder device. A movement amount suppressing means for suppressing the movement amount of the pair of electrodes in the separating direction is provided, and the base is engaged with the lower portion of the other electrode and added to the object to be welded. A force approximately equal to the load of the pair of electrodes and one cylinder device, etc. is applied in the direction opposite to the direction of the load applied to the other electrode, and the welding line of the work piece of the pair of electrodes is welded. A roll spot welding machine, which is provided with elastic urging means having a support plate attached to an upper portion thereof for holding a position to be clamped.