JPH0292470A - Roll spot welding machine - Google Patents

Abstract

PURPOSE:To execute satisfactory spot welding by constituting the title welding machine so that when one electrode abuts on an object to be welded, the other electrode follows up the one electrode direction, and always inserting and holding the object to be welded by prescribed pressing force. CONSTITUTION:By a movable arm 37, a pair of electrodes 2, 3 move to a position for inserting and holding an object to be welded. Subsequently, a cylinder 18 operates, a piston rod 18a elongates and one electrode 2 abuts on the object to be welded. Also, when the rod 18a advances, back pressure is generated, the cylinder head 18 moves to the upper part, and moves an electrode head 7 to the upper part through brackets 51, 52. The other electrode 3 moves from the lower part and by a pair of electrodes 2, 3, the object to be welded is inserted and held by prescribed pressing force. A pair of electrodes 2, 3 are guided along a weld line of the object to be welded by the robot arm 37, while executing an electric conduction, and execute desired roll spot welding. In such a way, even if a pair of electrodes are worn out and a pressure point of the electrode is deflected, the object to be welded is always inserted and held by prescribed pressing force and satisfactory welding can be executed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention involves sandwiching a welding line of a workpiece between a pair of electrodes,
The present invention relates to an improvement of a roll spot welding machine that performs roll spot welding while applying current and applying pressure along the weld line of the workpiece.

(Prior Art) A conventionally used roll spot melting tamper will be explained based on FIGS. 4 and 5.

In the figure, 1 is the roll spot welding machine body, 2.3
are a pair of electrodes provided on the roll spot welding machine main body l. 4 is an electrode head, and 5 is a power supply shaft having one electrode 2 of a pair of electrodes 2.3 attached to its tip. The power supply shaft 5 is rotatably fitted into the electrode head 4. A power supply block and lock 6 for supplying welding current are connected to the power supply shaft 5, and a welding transformer (not shown) is connected to the power supply block 6 via a secondary cable.

7 is the electrode head, 8 is the other electrode 3 of the pair of electrodes 2.3
This is a power supply shaft with a The power supply shaft 8 is rotatably fitted into the electrode rod 7. A power supply block 9 for supplying welding current is connected to the power supply shaft 8, and a welding transformer (not shown) is connected to the power supply block 9 via a secondary cable.

10 and 11 are brackets arranged on both sides of the electrode head 4.7, and 12.13 are guide rails arranged on both sides of the electrode head 4. The guide rail 12.13 is mounted on a base 14.15 (see also FIG. 6) which is fixed to the bracket 10.11.

Reference numeral 16.17 denotes a bearing (sliding member, hereinafter the same) that is slidably fitted to the guide rail 12.13.

Bearings 18, 17 are fixed to both sides of the electrode head 4, respectively. As a result, the electrode rad 4 slides up and down the guide rail 12.13 (see Figures 4 and 5).The electrode rad 7 is fixedly supported by the lower end of the bracket 1O111. .

1B is a pressurizing cylinder added to the top of the rad 4 for one electrode, and the piston rod 18 of the pressurizing cylinder 18
A knuckle 18 is attached to a. Further, a cylinder mounting plate 20 is fixed to the piston rod 18a side of the main body of the pressure cylinder 18, and a hole 20a through which the piston rod 18a of the pressure cylinder 18 passes is bored in the center of the cylinder mounting plate 20. ing.

Further, hinges 21 and 22 are provided on both sides of the hole 20a of the cylinder mounting plate 20, and these hinges 21.
22 and the hinge 23 in place on the bracket 10.11.
, 24 are rotatably connected to each other by hinge pins 25, 28. As a result, the pressurizing cylinder 18 is rotatably attached to the bracket 10.11.

Reference numeral 27 denotes a link fixed to one electrode head 4, and a long hole 28 is provided in the side surface of the link 27 perpendicular to the direction of movement of the Rad 4 to the electrode (vertical direction in FIG. 4) so that the Rad 4 can move to the electrode. is formed.

Reference numeral 29 denotes a link, and the base end of the link 29 is connected to a link 31.32 provided at an appropriate position on the bracket 10.11 by means of a pin 30.
It is rotatably connected. One side of the link 29 is rotatably attached to the link 2 by a pin 33 through the elongated hole 28.
7, and the other side of the link 29 is rotatably connected to the knuckle 13 by a pin 34.

35.38 is bracket to,! ! The mounting plate is fixed to the Thereby, the roll spot welding machine main body l is attached to a movable arm of a robot (not shown), that is, a robot arm 37 via attachment plates 35 and 36.

The roll spot welding machine configured as described above operates as follows.

A pair of electrodes 2.3 of the roll spot welding machine main body l attached to the robot arm 37 are connected to the workpiece (not shown).
When the robot arm 37 is positioned at a predetermined position, the robot arm 37
As a result, the welding start point of the workpiece is moved to a position where it is held.

Once the pair of electrodes 2.3 has moved, the pressurizing cylinder 1B is operated to extend the piston rod 18a of the pressurizing cylinder 18.

When the piston rod 18a of the pressure cylinder 18 extends, the pressure force of the pressure cylinder 18 is applied to the knuckle 19 and the link 2.
3. The signal is transmitted to the hinge 27, the electrode head 4 is moved along the guide rail 12.13 in the direction of the electrode head 7, and the welding start point of the workpiece is applied with considerable pressure by the pair of electrodes 2.3. to hold.

Then, once the welding start point of the object to be welded is clamped.

The pair of electrodes 2.3 are energized, and the robot arm 37
Since the robot arm 37 is taught to guide the roll spot welding machine main body l along the welding line of the workpiece, the robot arm 37 guides the roll spot welding machine main body l along the welding line of the workpiece. .

As a result, the pair of electrodes 2.3 performs roll spot welding while rotating along the welding line of the workpiece due to the electrode pressurizing force on the workpiece and the driving force of the robot arm 37.

In this way, the weld lines of the objects to be welded are roll spot welded, and when welding of all the desired weld lines of the objects to be welded is completed, the piston rod 18a of the pressure cylinder 1B is shortened, and the electrode head 4 is connected to the electrode. , in the direction away from the electrode 7, and the welding line is released from being held by the pair of electrodes 2.3.

When the welding line is released from the welding line, the robot arm 37 returns the roll spot welding machine main body 1 to its original position, and one cycle of roll spot welding is completed.

(Problem to be Solved by the Invention) However, in the above conventional roll spot welding machine, as welding is repeated, the pair of electrodes gradually wears out, and the pressure point of the pair of electrodes gradually shifts to one side. There was a problem in that one electrode was deviated from the other electrode.

Therefore, if welding continues, only one of the paired electrodes will come into contact with the workpiece, deforming or damaging the workpiece, resulting in welding defects. .

In order to prevent damage to the workpiece and welding defects due to wear of the pair of electrodes, the operation of the roll spot welding machine must be stopped at regular intervals, and the amount of wear of the pair of electrodes must be reduced. This poses a problem in that the movement of the robot arm must be corrected by the value, which places an extra burden on the worker and reduces productivity. .

In addition, since the pressurizing force of the pressurizing cylinder is transmitted to the pair of electrodes via a link, etc., the pressurizing force to the electrodes is dispersed, and there is also the problem that sufficient pressurizing force is not transmitted to the pair of electrodes. Ta. Therefore, in order to obtain sufficient pressurizing force, the output of the pressurizing cylinder had to be considerably increased.

The present invention was made with the aim of solving the above-mentioned conventional problems.Even if a pair of electrodes is worn out, if one electrode comes into contact with the workpiece, the other electrode will follow the other electrode. An object of the present invention is to provide a roll spot welding machine which corrects the deviation of the electrode by bringing it into contact with the object to be welded, and eliminates the above-mentioned drawbacks.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a pair of electrodes 2 and 3.
A roll spot welding machine main body 50 equipped with the above is attached to a movable arm, a workpiece to be welded is held between the pair of electrodes 2.3, and the workpiece is welded by the pair of electrodes 2.3 by the movable arm. In a roll spot welding machine that performs roll spot welding by applying current and applying pressure while guiding along a line, an electrode head 4 rotatably supporting one electrode 2 of the pair of electrodes 2.3 is attached to the roll spot welding machine. The electrode head 4 is connected to the piston rod 18a of the cylinder 18 provided in the welding machine main body 50, and supports the base end in the longitudinal direction of the electrode head 4 having the one electrode 2 so as to be slidable in the electrode pressing direction of the cylinder 18. , an electrode head 7 rotatably supporting the other electrode 3 of the pair of electrodes 2.3 is connected to the main body of the cylinder 18, and a base end in the longitudinal direction of the electrode head 7 having the other electrode 3; The cylinder 18 is configured such that the cylinder 18 is slidably supported in the electrode pressurizing direction.

(Function) With the above configuration, when the workpiece is positioned at a predetermined position, the pair of electrodes 2.3 of the roll spot welding machine main body 50 sandwich the welding start point of the workpiece by the movable arm. be moved as far as possible. a pair of electrodes 2,
When the electrodes 3 move to a position where they can grip the welding start point, the cylinder 18 is actuated, the piston rod 18a is extended, and one electrode 2 comes into contact with the object to be welded. Further advancement of the piston rod 18a creates back pressure, which causes the body of the cylinder 18 to move upward, causing the rad 7 to move upward toward the electrode.

As a result, the other electrode 3 moves from below to the one electrode side and comes into contact with the workpiece, and the pair of electrodes 2.3 presses the welding start point of the workpiece with a constant pressure (referred to as electrode pressure). hold it in place. This back pressure acts until the electrode pressing force of one electrode 2 and the electrode pressing force of the other electrode 3 become equal. Therefore, the weld line of the object to be welded is always held between the pair of electrodes 2.3 with a constant electrode pressure.

Further, the piston rod 18a of the cylinder 18 and the pair of electrodes 2.3 move in the same direction, and the pair of electrodes 2.3
Since the proximal end of the electrode head in the longitudinal direction is supported, the pressing force of the cylinder 1B is transmitted to the pair of electrodes 2.3 without significant loss.

When the welding starting point of the workpiece is clamped, a pair of electrodes 2.
3 is guided by the robot arm 37 along the welding line of the workpiece while being energized, and performs the desired roll spot welding. When all the desired roll spot welding is completed, the pressure cylinder is actuated to move the piston rod 18a. shorten it,
The clamping of the object to be welded between the pair of electrodes 2 and 3 is released, and the robot arm 37 returns the roll spot welding machine main body 50 to its original position to complete one cycle of roll spot welding.

(Example) Next, an example of the present invention will be described based on FIGS. 1 to 3.

Note that the same parts as those of the conventional one are given the same reference numerals and detailed explanations are omitted.

In the figure, 50 is the roll spot welding machine main body, 51,
Reference numeral 52 designates brackets disposed on both sides of the electrode pads 4.7 that rotatably support the pair of electrodes 2.3. One end of the bracket 51, 52 (the upper part in FIG. 2) is fixed to the main body of the pressurizing cylinder 18, and the other end is fixed to both sides of the electrode head 7 to support the pad 7 to the electrode. There is. therefore.

The electrode pad 7 rotatably supporting the other electrode 3 of the pair of electrodes 2.3 is connected to the main body of the pressurizing cylinder 18.

53 and 54 are brackets arranged inside the plastic brackets 51 and 52. One end of the bracket 53, 54 (the upper part in FIG. 2) is fixed to a knuckle 55 attached to the piston rod 18a of the pressurizing cylinder 18, and the bracket 53, 54 is further fixed to both sides of the electrode head 4. supports the electrode head 4. Hence the pressurized cylinder! The electrode rod 4 moves up and down in FIG. 1 by the expansion and contraction of the piston rod 18a.

5B is a base fixed to the robot arm 37, and the roll spot welding machine main body 50 is attached to the robot arm 37 via this base 5B. A pair of guide rails 57 and 58 are fixed to the base 56 in parallel to the direction of expansion and contraction of the piston rod 18a of the pressure cylinder 18.

59, 80, 131.82 is a pair of guide rails 57.
58, and the bearing 5S is fixed to the bracket 52, and the bearing 5S is slidably fitted to the electrode head 7.
The bearing 60 is fixed to the bracket 54 and supports the longitudinal proximal end of the rad 4 to the electrode, and the bearing 6I is fixed to the bracket 53 and supported to the electrode. The base end in the longitudinal direction of the rad 4 is supported, and the bearing 62 is fixed to the bracket 51 to support the base end in the longitudinal direction of the rad 7 to the electrode. That is, the electrode rad 4 is slidably supported from the rear by bearings 60 and 81, and the electrode rad 7 is supported by a bearing 59.
and 82 are slidably supported from the rear.

83, 84 are stopper brackets fixed to the ends of one of the pair of guide rails 57, 57 by ports 65, 68, and stopper brackets f13.
A stopper 67 and a stopper C8 are attached to each of the stoppers 84 and 84, respectively.

In addition, each portion of the bracket 53 and the bracket 51 facing the stopper bracket 63, 84 has a stopper 67.
．． A stop 63.70 is mounted for engagement with 68. That is, a stopper 69 for engaging with the stopper B7 is attached to the bracket 53, and a stopper 70 for engaging with the stopper 68 is attached to the bracket 51, respectively.

By providing such stoppers 67.89 and 68.70, when moving the roll spot welding machine main body 50 to a predetermined position t, the pair of electrodes 3.4 provided on the roll spot welding machine main body 50 are It can be locked and the roll spot welding machine body 50 can be moved at high speed, which has the effect of shortening the welding cycle and improving productivity.

The operation of the roll spot welding machine configured as above will be explained.

The roll spot welding machine body 50 is attached to the robot arm 37, and the piston rod 18a of the pressure cylinder 18 attached to the roll spot welding machine body 50 is in a shortened state and waiting at its original position.

When the piston rod 18a of the pressure cylinder 18 is shortened, the bracket 53 moves upward, and the stopper 69 formed on the bracket 53 comes into contact with the stopper 67 (see Figures 1 and 3), and the piston rod 18a is further shortened. Then, back pressure is generated due to the contact between the stopper 63 and the stopper 67.

When such back pressure is generated, the main body of the pressurizing cylinder 18 moves downward due to the back pressure, so that the bracket 51 also moves downward, and the stopper 68 comes into contact with the stove/puff 0. Therefore, the pair of electrodes 2.3 are locked in the state shown in FIGS. 1-3.

In this state, when the workpiece (not shown) is positioned at a predetermined position, the robot arm 37 allows the pair of electrodes 2.3 of the roll spot welding machine main body 50 to clamp the welding start point of the workpiece. be moved to a certain position. During this time, the pair of electrodes 2.3 are locked, so even if the robot arm 37 moves the roll spot welding machine main body 50 at a considerable speed, the pair of electrodes 2.3 will not swing.

When the pair of electrodes 2.3 move to a position where they can hold the welding start point, the pressurizing cylinder 18 is activated and the piston rod 18a is extended. the piston rod 18a
When the cylinder moves forward, back pressure is generated. Due to this back pressure, the main body of the pressurizing cylinder 18 moves upward in the figure, and the body of the pressure cylinder 18 moves upward in the figure.
．． Move the rad 7 upwards through 52 to the electrode. As a result, the other electrode 3 contacts the object to be welded from below and clamps the object to be welded.

This back pressure acts until the electrode pressing force of one electrode 2 and the electrode pressing force of the other electrode 3 become equal. therefore,
The weld line of the object to be welded is held between the pair of electrodes 2.3 with constant electrode pressure.

When the welding start point of the workpiece is clamped, a pair of electrodes 2,
3 is guided by the robot arm 37 along the welding line of the workpiece while being energized, and performs the desired roll spot welding. When all the desired roll spot welding is completed, the pressurizing cylinder 18 is actuated to release the piston rod 18a. is shortened to release the clamping of the workpiece by the pair of electrodes 2.3, lock the pair of electrodes 2.3, and return the roll spot welding machine main body 50 to its original position by the robot arm 37 to release the workpiece to be welded by the pair of electrodes 2.3. One cycle of welding is completed.

(Effects of the Invention) Since the present invention is configured as described in detail above, when one electrode of a pair of electrodes comes into contact with the object to be welded, the other electrode follows in the direction of the one electrode. With this structure, even if the pair of electrodes is worn out and the electrode pressurizing point is displaced, the workpiece to be welded can always be held with a constant pressurizing force. Therefore, excellent roll spot welding can be performed without damaging the workpiece or producing welding defects.

Additionally, this eliminates the need to correct the motion of the robot arm, which eliminates an extra burden on the worker, improving productivity.

Furthermore, since the pressure direction of the cylinder and the direction in which the pair of electrodes clamp the workpiece are aligned, and the base ends of the pair of electrode heads in the longitudinal direction are backed up from the rear, the electrode pressure force of the cylinder can be reduced. It is transmitted to a pair of electrodes with almost no loss.

Therefore, the capacity of the cylinder can be minimized, manufacturing costs can be reduced, and the roll spot welding machine main body can be made compact.

This also reduces the weight of the roll spot welding machine, and the robot that attaches the roll spot welding machine to the machine can also be made smaller, reducing equipment costs for the entire equipment. play.

[Brief explanation of drawings]

Fig. 1 is a front view of the roll spot welding machine main body showing an embodiment of the present invention, Fig. 2 is a side view of the roll spot welding machine main body, Fig. 3 is a rear view of the roll spot welding machine main body, and Fig. 4 is a rear view of the roll spot welding machine main body showing an embodiment of the present invention. FIG. 6 is a front view of the conventional roll spot welding machine main body with one bracket removed, No. 5rI4 is a side view of the conventional roll spot welding machine main body, and FIG. 6 is a plan view of the conventional roll spot welding machine main body. 50...Roll Spoiler/ ) Welding machine body 2... One electrode 3... Other electrode 4... Electrode head 7... Electrode head 18... Cylinder 18a... Piston rod 37. ...Robot arm (movable arm) patent

Claims (1)

[Claims] (1) A roll spot welding machine body equipped with a pair of electrodes is attached to a movable arm, a workpiece is held between the pair of electrodes, and the movable arm connects the pair of electrodes to the welding line of the workpiece. In a roll spot welding machine that performs roll spot welding by applying current and applying pressure while being guided along the roll spot welding machine, an electrode head rotatably supporting one of the pair of electrodes is provided on the roll spot welding machine body. The base end in the longitudinal direction of the electrode head connected to the piston rod of the cylinder and having the one electrode is supported slidably in the electrode pressing direction of the cylinder, and the other electrode of the pair of electrodes is rotatable. The electrode head supported by the cylinder is connected to the main body of the cylinder, and the base end in the longitudinal direction of the electrode head having the other electrode is supported slidably in the electrode pressing direction of the cylinder. roll spot welding machine.