JPH06226457A - Welding device - Google Patents

Abstract

PURPOSE:To immediately start a welding processing after relative positioning of both works is completed and to shorten the welding time. CONSTITUTION:A spot welding gun 2 and a clamping device 3 for holding a small-sized work 4 are provided on a robot arm 1 and a positioning jig 19 which positions and holds a base work 5 is provided fixedly on the specified position. After the clamping device 3 holds the small-sized work 4, the robot arm 1 is moved to the specified welding processing position and the relative positioning of both works 4 and is carried out. At this time, a back bar electrode 9 fitted to the positioning jig 19 is abutted on the welding point of the base work 5, the spot welding gun 2 is located above the welding point and in a state that the clamping device 3 holds the small-sized work 4, the spot welding gun 2 operates and performs welding processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding device for welding by accurately matching the relative positions of two objects to be welded.

[0002]

2. Description of the Related Art Generally, in a welding line, as a first step, two workpieces are accurately positioned relative to each other and then welded at one or more points to maintain the relative positions of both workpieces. Temporary welding is performed, and then, as a second step, welding of a portion other than the temporary attachment portion, which is referred to as over-strike, is performed.

In the above welding line, conventionally, a welding robot having a spot welding gun provided at the end of a robot arm has been used. In the case of performing the above-mentioned tack welding using such a welding robot, conventionally, after the two works are set on a positioning jig for positioning and holding the two works, the welding robot is operated. There is. That is, the spot welding gun is made to stand by at a predetermined standby position until the two workpieces are set on the positioning jig, and after the workpieces have been set, the welding robot moves the spot welding gun to the welding point. .

In the above case, the welding robot is in a standby state until the two workpieces have been set on the positioning jig, and the operating rate of the robot cannot be increased, and after the workpieces have been set, the spot welding gun is set to the standby position. It takes time to move from the welding process to the welding point, which causes a decrease in the welding processing speed.

By the way, in Japanese Utility Model Laid-Open No. 64-38184, a pair of welding electrodes for holding a work and an air cylinder for moving one welding electrode forward and backward toward the other welding electrode are provided at the end of a robot arm. A welding robot equipped with a provided spot welding gun and a clamp device for clamping a work is disclosed. Therefore, by using a welding robot provided with a spot welding gun and a clamp device at the end of the robot arm, the operating rate of the robot and the welding processing speed can be increased.

That is, in the welding robot, after one of the two workpieces to be welded is set on the positioning jig, the other workpiece is clamped by the clamp device and conveyed to the positioning jig, and the robot itself. Sets the work on the positioning jig. After this, the welding robot releases the clamp of the clamp device, moves the spot welding gun to the welding point, holds the two workpieces by the pair of welding electrodes, and energizes the pair of welding electrodes under pressure by the air cylinder. And weld the two workpieces. As described above, in the above welding robot, since the robot itself carries the workpiece to be welded and sets it on the positioning jig, the operation rate of the robot is high, and further, the workpiece is set on the positioning jig. After the completion, it is possible to shift to the spot welding process by the spot welding gun on the spot, so that the welding processing time can be shortened as compared with the normal welding robot.

[0007]

However, in the above-mentioned conventional configuration, the spot welding gun is moved to the welding point after the work is transferred from the clamp device provided on the robot side to the positioning jig side. Two workpieces are sandwiched by a pair of welding electrodes, and after the workpieces have been set on the positioning jig, the spot welding gun must be moved and moved before the spot welding process (pressurization, energization) is started. It takes time for the work to be clamped by the pair of welding electrodes. That is, in the above conventional configuration,
The problem arises that the spot welding process cannot be started immediately after the relative positioning of the two workpieces is completed.

The present invention has been made in view of the above, and an object thereof is to be able to start the welding process immediately after the relative positioning of two workpieces (objects to be welded) is completed. An object of the present invention is to provide a welding device capable of shortening the processing time.

[0009]

A welding apparatus of the present invention is a welding device in which a first welded object and a second welded object are sandwiched between opposing first and second welding electrodes, A resistance welding means for performing a welding process for welding both the objects to be welded by energizing the both electrodes, and a movable support provided movably (for example,
A robot arm) and the movable support,
A first holding means for holding an object to be welded, and a first holding means fixedly provided at a predetermined position within a moving range of the moving support body;
A second holding means for positioning and holding an object to be welded, and a control means for controlling the operations of the resistance welding means, the moving support, and the first holding means are provided to solve the above problems. In addition, it is characterized by taking the following means.

That is, the first welding electrode of the resistance welding means is attached to the movable support so that the electrode position during the welding process corresponds to the welding point of the first object to be welded held by the first holding means. The second welding electrode of the resistance welding means is provided on the second holding means so as to correspond to the welding point of the second workpiece to be positioned and held by the second holding means, and the control means is The holding and moving support is predetermined so that the welding point of the first object to be welded held by the first holding means and the welding point of the second object to be welded positioned and held by the second holding means coincide with each other. The resistance welding means and the movable support so that the resistance welding means performs the welding processing after the first holding means holds the first object to be welded. And controlling the operation of the first holding means. .

[0011]

According to the above construction, the movable support provided movably has the first holding means for holding the first object to be welded,
The first welding electrode of the resistance welding means is provided, and the second holding means for positioning and holding the second object to be welded is provided at a predetermined position within the moving range of the moving support.

The moving support is controlled by the control means to move to a predetermined welding processing position.
At this welding process position, the first holding means holds the first holding means.
The welding point of the object to be welded and the welding point of the second object to be welded, which is positioned and held by the second holding means, are matched. That is, the first holding means holds the first object to be welded, and the second support means is positioned and held by the second holding means while the movable support is moved to the welding processing position. Positioning is performed relative to the object, and the work (first holding means) from the clamp device (first holding means) provided on the robot (moving support) side to the positioning jig (second holding means) is provided as in the conventional case. There is no need to deliver the work piece).

As described above, the first work piece and the second work piece are welded.
In a state where relative positioning with respect to the object to be welded, the first welding electrode of the resistance welding means corresponds to the welding point of the first object to be welded whose electrode position during the welding process is held by the first holding means. The second welding electrode of the resistance welding means is present at a position corresponding to the welding point of the second object to be welded which is positioned and held by the second holding means. Therefore, it becomes possible to start the welding process immediately after the relative positioning of the first and second objects to be welded by the movement of the movable support body to the welding process position. It is possible to shorten the welding process time.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

The welding apparatus according to the present embodiment precisely positions a relatively small work piece and another work piece, and then welds a predetermined one place to determine the relative position of the two work pieces. It is used for so-called tack welding, which is the first step of the welding line for holding.

As shown in FIG. 1, the welding apparatus includes a robot arm (movable support) 1, and a free end 1a of the robot arm 1 has a pressing device 6 and a welding electrode (first electrode). Spot welding gun 2 having a welding electrode 8
And a clamp device (first holding means) 3 for holding a small work piece (first object to be welded) 4. The relative positional relationship between the spot welding gun 2 and the clamp device 3 is constant, and this relative position is set according to the shape of the small work 4 and its welding point.

In this embodiment, an air cylinder device is used as the pressurizing device 6 for the spot welding gun 2, and an electrode for attaching and detaching the welding electrode 8 is attached to the end of the output shaft 6a of the air cylinder device. The mounting portion 7 is fixed. An insulating means (not shown) is provided at a connecting portion between the output shaft 6a and the electrode mounting portion 7 to electrically insulate the both 6a and 7 from each other.

The above welding apparatus is equipped with a welding transformer (not shown), and the output power from this welding transformer is the welding electrode 8 mounted on the electrode mounting portion 7 via the cable 10 and the conductors 11 and 12. To be supplied to. The conductors 11 and 12 are attached to the spot welding gun 2 by an insulator 13. The conductor 12 is in contact with the outer peripheral surface of the electrode mounting portion 7, and even if the electrode mounting portion 7 is displaced in the vertical direction by the operation of the pressure device 6, the conductor 12 and the electrode mounting portion 7 slide. By moving, the electrical connection between the two is maintained.

The spot welding gun 2, the welding transformer, and a back bar electrode 9 described later constitute a spot welding device 20 (see FIG. 4) as resistance welding means.

The clamp device 3 has an air cylinder device 14, and a hand portion 15 for clamping the small work 4 is provided at the end of the output shaft 14a of the air cylinder device 14.

As shown in FIGS. 2 and 3, the hand portion 15 has a driving cylinder device at each upper end portion of a pair of operating portions 16 and 16 pivotally mounted by shafts 16a and 16a. The main body 17a of 17 and the output shaft 17b are pivotally mounted. Also, this hand unit 1
The small work 4 is provided with positioning pins 18, 18 which are inserted into positioning holes (not shown) formed in the upper part of the small work 4 to position the clamp position of the small work 4. Can be clamped at the correct position. That is, the small work 4 is the hand part 1
In the state of being clamped at 5, the relative positional relationship between the small work 4 and the hand portion 15 is always constant.

Further, the above welding apparatus is provided with a positioning jig (second holding means) 19 for positioning and holding a base work (second workpiece) 5 to which the small work 4 is welded. The positioning jig 19 is fixedly provided at a predetermined position within the movement range of the robot arm 1. The positioning jig 19 includes a plurality of positioning clamp portions 19a, which are vertically provided on a jig base 19a, and the positioning clamp portion 19a has a positioning pin and a clamp device (not shown). A back bar electrode (second welding electrode) 9 is attached to the jig base 19a so that the welding point of the base work 5 set on the positioning jig 19 abuts on the jig base 19a. The back bar electrode 9 is connected to the welding transformer via a cable (not shown).

As shown in FIG. 4, the welding apparatus has a control device (control means) 21 including a microcomputer for controlling the operations of the robot arm 1, the spot welding device 20 and the clamp device 3. The control device 21 enables automatic operation of the device.

The operation of the welding apparatus having the above structure will be described below.

First, the base work 5 is set on the positioning jig 19 by a transfer means (not shown) such as a transfer robot. The base work 5 is the positioning jig 1
In the state of being set to 9, the back bar electrode 9 contacts the welding point on the lower surface of the base work 5.

On the other hand, as shown in FIG. 5, the controller 21 moves the robot arm 1 to the mounting position of the unwelded small work 4 (S1), and at this position, the robot arm 1
The small work 4 is clamped by the hand portion 15 of the clamp device 3 provided at the end of (S2). This hand part 1
When the small work 4 is clamped by the small work 4, the small work 4 is clamped at an accurate position by inserting the positioning pins 18, 18 provided in the hand portion 15 into the positioning holes formed in the small work 4. To be done.

Next, the controller 21 controls the robot arm 1
Is moved to the welding processing position (S3). The welding processing position is set so that the robot arm 1 is moved so that the welding point of the base work 5 positioned and held by the positioning jig 19 and the welding point of the small work 4 held by the hand unit 15 coincide with each other. It is the position. Therefore, by moving the robot arm 1 to the welding processing position while the small work 4 is held by the hand portion 15, as a result, the small work 4 is positioned and held on the base work 5 at a predetermined position. Then, the assembly work of the small work 4 and the base work 5 is completed.

After that, the control device 21 causes the spot welding device 20 to execute the welding process while the hand portion 15 holds the small work 4 (S4). That is, the control device 21 first operates the pressurizing device 6 of the spot welding gun 2. As a result, the welding electrode 8 is displaced downward, and the small work 4 and the base work 5 sandwiched between the welding electrode 8 and the back bar electrode 9 are pressed. The pressurization by the pressurizing device 6 is released in a short time, but during this pressurization, the control device 21 controls the welding transformer so that the electrodes 8 and 9 are energized. Thereby, the small work 4 and the base work 5 are welded (temporarily welded) in a state where the positioning is accurately performed.

After the above welding process is completed, the controller 21
Releases the clamped state of the small work 4 by the hand portion 15 (S5), and moves the robot arm 1 from the welding processing position to the mounting position of the unwelded small work 4 again (S5).
1).

On the other hand, the base work 5 to which the small work 4 is welded is removed from the positioning jig 19 by a transfer means such as a transfer robot (not shown), and transferred to the station for the next step, the additional step. Become.

After that, by repeating the above-mentioned operation, temporary welding of the small work 4 and the base work 5 is continuously performed.

As described above, in the welding apparatus of this embodiment, the spot welding gun 2 and the clamp device 3 for holding the small work 4 are provided at the free end 1a of the robot arm 1 and the base work 5 is attached. A positioning jig 19 for positioning and holding is fixedly provided at a predetermined position within the movement range of the robot arm 1, and the spot welding gun 2 and the clamp device 3 have a predetermined positional relationship, that is, welding in the spot welding gun 2. The position of the welding electrode 8 at the time of processing is such that it corresponds to the welding point of the small work 4 held by the clamp device 3, and the back bar electrode 9 is
Base work 5 positioned and held by the positioning jig 19
The positioning jig 19 is provided so as to correspond to the welding points of the positioning jig 19, and the control device 21 controls the welding point of the small work 4 held by the clamp device 3 and the positioning jig 1.
After moving the robot arm 1 to a predetermined welding processing position so that the welding point of the base work 5 positioned and held at position 9 is aligned, the clamp device 3 holds the small work 4 in place. , Spot welding equipment 2
The robot arm 1, the clamp device 3, and the spot welding device 20 are controlled so that the welding process can be performed by 0.

Therefore, in the welding apparatus according to the present embodiment, the robot arm 1 holds the small work 4 by the clamp device 3.
Is moved to the welding processing position, the relative positioning between the base work 5 and the small work 4 which are positioned and held by the positioning jig 19 is performed.
It is not necessary to transfer the work from the clamp device provided on the robot side to the positioning jig side.

As described above, in the state where the base work 5 and the small work 4 are relatively positioned, the back bar electrode 9 is in contact with the welding point on the lower surface of the base work 5 and spot welding is performed. When the gun 2 is located above the welding point of the small work 4 and the spot welding gun 2 is operated, the welding electrode 8 is moved to the small work 4
It corresponds to the welding point of. Therefore, the welding process (pressurization, energization) can be started immediately after the relative positioning of the base work 5 and the small work 4 is performed, and the welding processing time can be shortened as compared with the conventional case. be able to.

The spot welding apparatus 20 of this embodiment is
Although it is configured to perform single spot welding, the present invention is not limited to this. For example, a spot welding gun is provided with a plurality of welding electrodes (first welding electrodes) and a back bar electrode (second welding electrode) is provided. Can be used as a common electrode for the plurality of welding electrodes, and multi-spot welding including two or more welding points can be performed.
It is also possible to form projections at the welding points of the small work 4 or the base work 5 to perform projection welding.

[0036]

As described above, the welding apparatus of the present invention can be used in a state where the first and second objects to be welded are sandwiched between the opposing first and second welding electrodes. A resistance welding means for performing a welding process of energizing the both electrodes to weld the both objects to be welded, a movable support provided movably, and a first object to be welded provided on the movable support. First holding means for holding, second holding means fixedly provided at a predetermined position within the moving range of the movable support body, for positioning and holding the second workpiece, the resistance welding means, the movable support body, and Control means for controlling the operation of the first holding means, and the first welding electrode of the resistance welding means is for welding the first work piece whose electrode position during the welding process is held by the first holding means. Corresponding to the points, provided on the moving support, the resistance welding hand Second welding electrode is provided on the second holding means so as to correspond to a welding point of the second workpiece to be positioned and held by the second holding means, and the control means is held by the first holding means. The holding and moving support is moved to a predetermined welding processing position so that the welding point of the first welded object and the welding point of the second welded object positioned and held by the second holding means coincide with each other. After that, the operation of the resistance welding means, the moving support, and the first holding means is performed so that the resistance welding means performs the welding process while the first holding means holds the first object to be welded. Is a configuration for controlling the.

Therefore, the first holding means holds the first object to be welded, and the movable support moves to the welding processing position, whereby the second object to be welded and the second object to be positioned and held by the second holding means. (1) Relative positioning with respect to the object to be welded is performed, and the welding process can be started immediately after this, which brings about an effect that the welding process time can be shortened as compared with the conventional case.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a schematic front view of a welding apparatus.

FIG. 2 is a schematic front view showing a hand portion of a clamp device in the welding device.

FIG. 3 is a schematic side view showing the hand unit.

FIG. 4 is a block diagram showing a configuration of a main part of the welding device.

FIG. 5 is a flowchart showing a control operation of a control device in the welding device.

[Explanation of symbols]

 1 Robot Arm (Movable Support) 2 Spot Welding Gun 3 Clamping Device (First Holding Means) 4 Small Workpiece (First Workpiece) 5 Base Workpiece (Second Workpiece) 8 Welding Electrode (First Welding Electrode) 9 Back Bar Electrode (Second Welding Electrode) 15 Hand Part 18 Positioning Pin 19 Positioning Jig (Second Holding Means) 20 Spot Welding Device (Resistance Welding Means) 21 Control Device (Control Means)

Claims (1)

[Claims] 1. A first welding object and a second welding object are sandwiched between opposing first and second welding electrodes,
A resistance welding means for performing a welding process of energizing the both electrodes to weld the both objects to be welded, a movable support provided movably, and a movable support provided on the movable support to hold a first object to be welded. First holding means for fixing, a second holding means fixedly provided at a predetermined position within the moving range of the movable support body, for positioning and holding a second workpiece, the resistance welding means, the movable support body, and the second support means. Control means for controlling the operation of the first holding means, the first welding electrode of the resistance welding means corresponds to the welding point of the first object to be welded whose electrode position during the welding process is held by the first holding means. The second welding electrode of the resistance welding means is provided on the movable support so as to correspond to the welding point of the second workpiece to be positioned and held by the second holding means. Is provided in the means, and the control means is The holding and moving support is predetermined so that the welding point of the first object to be welded held by the first holding means and the welding point of the second object to be welded positioned and held by the second holding means coincide with each other. The resistance welding means and the movable support so that the resistance welding means performs the welding processing after the first holding means holds the first object to be welded. And a welding device for controlling the operation of the first holding means.