JPS6236791B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention provides the following features for one robot arm:
The present invention relates to a welding robot in which a necessary gun can be selected from among a plurality of spot welding guns at a predetermined position and can be attached and detached, and particularly relates to a structure for attaching a gun to a robot arm.

For example, welding robots used in automobile assembly processes usually have one spot welding gun per robot. If the mounting structure of both is not robust, it will affect welding accuracy, so unless there are special circumstances such as maintenance, the spot welding gun is rarely removed from the robot. Generally, the structure is not such that it can be actively attached and detached.
However, for example, in a mixed production line, which is one type of automobile assembly, multiple car models with different specifications and models are assembled on one common line. It is recognized that making it possible for a robot to perform welding by switching between multiple spot welding guns is highly effective in terms of generalization.

If we aim to make the spot welding gun more versatile by proactively attaching and detaching it, as mentioned above, and if the attachment and detachment work is performed only by movement on the robot side, the spot welding gun will not be able to operate during normal welding. It has excellent robustness so that it will not come off, and on the other hand,
When detaching from the robot, seemingly contradictory functions are required to enable easy and quick removal.

In view of the above points, it is an object of the present invention to provide a spot welding gun mounting device that can satisfy the above requirements. This will be explained based on an example.

That is, FIG. 1 shows an example in which two spot welding guns 2 and 3 can be attached to and replaced with one articulated welding robot 1 as appropriate. In the figure, 1 is the aforementioned welding robot, 2 is an X-shaped spot welding gun, and 3 is a welding robot.
is a C-shaped spot welding gun, 4 and 5 are stands arranged in parallel as standby positions (origin positions) for each spot welding gun, and each spot welding gun 2 and 3 is individually positioned on the stands 4 and 5. Each one is waiting in its own form. In the drawing, an X-shaped spot welding gun 2 is connected to the tip of the robot arm 6. Here, since both the frames 4 and 5 are the same, one will be explained. As shown in FIG. 2, a face plate 7 is integrally attached to the upper end of the frame 4. A locate hole 9 is formed in each. By fitting the post portion 10 and locate pin 31 on the spot welding gun 2 side into these support holes 8 and locating holes 9, the rotational direction and vertical position of the spot welding gun 2 are regulated, and the spot welding gun 2 are positioned in a certain direction.

Further, in FIG. 2, reference numeral 11 denotes a bracket attached to the tip of the robot arm 6, and this bracket 11 has a striker insertion hole 12 with a rectangular cross section extending in a direction perpendicular to the axis of the robot arm 6. In addition, a lock pin 13 is provided which is perpendicular to the striker insertion hole 12. The lock pin 13 is moved up and down by the operation of an actuator 14 attached to the lower surface of the bracket 11, so that its wedge tip 13a enters and retracts into the striker insertion hole 12. Reference numeral 15 denotes a limit switch as a detection means attached to the side of the bracket, which confirms and detects whether a mount striker 16, which will be described later, has been inserted into the striker insertion hole 12 to a specified position.

On the other hand, 16 is a mounted striker that is integrally attached to the base end 17 of the X-shaped spot welding gun 2. As shown in FIG. A roller 20 whose rotation center is an axis 19 that intersects with the mount striker 16 is inserted into the striker insertion hole 12, as shown in the figure, and a lock pin is attached to the engaging portion 21. The wedge-shaped sharpened portion 13a of 13 engages, and its sloped surface comes into sliding contact with the roller 20, and the mount striker 16 and the bracket 11 are firmly fixed by the wedge action. The configuration of this mount striker 16 is that of a C-type spot welding gun 3.
are also exactly the same, so the explanation here will be omitted. In addition, 22 in Fig. 1 is a transformer, 2
3 is a power supply cable, 24 is a cooling water hose, and 25 is a switch for detecting the presence or absence of the gun 3.

Therefore, in the above configuration, when performing welding work using only the X-shaped spot welding gun 2, the operation of the robot 1 causes the X-shaped spot welding gun 2 to leave the base 4, which is the origin position, and move to a predetermined position. After moving to the welding point position and performing predetermined welding, it returns to the pedestal 4 and is always positioned at a constant position on standby. The above operation is then repeated unless there is an instruction to attach or detach the gun.

On the other hand, when there is an instruction to attach or detach the gun, the lock pin 13 and the mount striker 16 are disengaged by first moving the actuator 14 shown in FIG. 2 downward. At this time, the X-shaped spot welding gun 2 remains positioned on the pedestal 4 without any movement. Then, the robot 1 moves the bracket 11 horizontally based on the information stored in advance, removes it from the mount striker 16, and then removes it from the mount striker 16.
Turn it 180 degrees and insert it into the mount striker 16 of the C-shaped spot welding gun 3 waiting on the stand 5 side. Contrary to the above, the lock pin 13 is moved upward by the operation of the actuator 14 and engaged with the mount striker 16, thereby attaching the C-shaped spot welding gun 3 to the bracket 11.
Concatenate. With the above steps, the work of switching the X-type spot welding gun 2 to the C-type spot welding gun 3 is completed.

In this way, by appropriately switching the gun from the X-type to the C-type or from the C-type to the X-type, the welding process can be made more versatile.

As is clear from the above description, according to the present invention, a bracket having a striker insertion hole is attached to the tip of the robot arm, and the wedge-shaped sharp portion slides into the bracket by the operation of the actuator. While a lock pin that retracts from the striker insertion hole is provided, a nearly U-shaped mounted striker is integrally provided at the base end of the spot welding gun, and spot welding is performed by engaging the wedge-shaped tip of the lock pin with the mounted striker. The gun is removably attached to the robot arm, and it not only greatly contributes to the versatility of welding work using spot welding guns, but also allows for quick attachment and replacement, as well as structural allocation. It has the advantage of providing great mounting strength, as well as having a small number of parts and excellent reliability. In addition, since the bracket is provided with a detection means for detecting the coupling state between the mount striker and the striker insertion hole, for example, by establishing an interlock between the detection output and the robot control system, the robot arm and The state of connection with the gun can be checked to prevent the gun from falling off, further improving its reliability and safety.

[Brief explanation of the drawing]

FIG. 1 is an overall exploded view of a welding robot including the present invention, FIG. 2 is a sectional view of a main part of FIG. 1, and FIG. 3 is a plan view of the mount striker in FIG. 2. DESCRIPTION OF SYMBOLS 1... Welding robot, 2... X-type spot welding gun, 3... C-type spot welding gun, 6... Robot arm, 11... Bracket, 12... Striker insertion hole, 13... Lock pin, 13a... Wedge-shaped pointed part, 14... Actuator, 15... Limit switch as detection means, 16... Mount striker, 17... Base end portion, 20... Roller.

Claims (1)

[Claims] 1. A welding robot capable of selecting a necessary spot welding gun from among at least two spot welding guns kept in standby at a predetermined position and attaching and detaching the gun, and a device for attaching the spot welding gun to the robot. A nearly U-shaped mount striker is integrally attached to the base end of the spot welding gun, and a bracket having a striker insertion hole into which the mount striker is inserted is attached to the tip of the robot arm. A lock pin is provided in the bracket, and the lock pin slides in a direction intersecting the striker insertion hole by actuation of an actuator included in the robot arm so that its wedge-shaped sharp end engages and disengages from the mount striker. 1. A spot welding gun mounting device for a welding robot, characterized in that the spot welding gun mounting device is provided with a detection means for detecting a state of coupling with a welding robot.