JPH043729Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a welding cylinder that is equipped with a detection mechanism that detects the movement of a piston in a cylinder that performs spot welding by pressurizing and energizing the cylinder.

[Problems to be solved by the prior art and the invention]

In conventional spot welding, as shown in FIG. 1, a chip c is pressurized toward a product b by a piston in a gun cylinder a, and current is applied to weld the chip c, which is generally widely used.

However, when chip c is pressurized and energized, chip c and product b are welded together, and even if compressed air is introduced to return the piston of cylinder a, a phenomenon occurs in which the welding force is stronger than the return force of the cylinder and does not return.

Therefore, in the case of automatic installation, if the above-mentioned welding occurs, unless some kind of detection device is provided, the gun unit A will proceed to the next operation, which will cause the following problem.

1 When the gun unit A moves the chip C while it is still welded to the product B, the chip C is removed from the shank d or the shank d is removed from the screw adapter e, and the cooling water flowing inside flows out to the outside. Also, the chip c will be welded and come off, making it impossible to perform the next weld.

Chip c, shank d, screw adapter, etc. are deformed.

2. If gun unit A is welded, it will not be able to move and the next operation will not be possible.

Therefore, in order to deal with this problem, a limit switch h attached to the fixed side is actuated by an arm g attached to a point holder shown in Fig. 2, and it is confirmed that the tip c has returned. As shown in Fig. 3, after welding is completed, a voltage is applied between the product b and the chip c to detect the presence or absence of welding based on the current value, or as shown in Fig. 4, a magnet i is attached to the piston p. There is a method of attaching a magnetic switch j to the outside of cylinder a at the piston return position and detecting it with the magnetic switch j, but the second method
In the case shown in the figure, there are often welding cables and cooling water hoses at the mounting location of the limit switch h, which poses a problem in terms of space. Also limit switch h
Since the mounting position of the chip c is close to the welding point, there is the problem that welding spatters may adhere to the chip c and cause malfunction. There are some problems that cannot be determined without doing so. Furthermore, Fig. 4 shows that although this is possible with commonly used cylinders, in cylinders used for welding, a magnetic field is generated when welding current is applied, and there are various problems such as the magnetic switch j often malfunctioning. .

[Means for solving problems]

In view of these circumstances, the present invention was developed to eliminate this problem by incorporating a reflective photoelectric switch in the head of the cylinder to be spot welded to detect the movement of the piston, thereby eliminating malfunctions caused by magnetic force. This is to ensure that motion is detected.

〔Example〕

Next, one embodiment of a welding cylinder equipped with a detection mechanism according to the present invention will be described based on the drawings.

1 is a cylinder whose interior is divided into two chambers A and B by a partition plate 2, into which pistons 4 and 4a connected by a piston rod 3 are slidably fitted, and furthermore, the upper and lower chambers A and B are provided in the piston rod 3. We communicate through the passage.

The tip of the piston rod 3 exposed from the cylinder 1 has a point holder 8 to which the shank 6 of the tip 5 is attached with a screw adapter 7, and the upper part of the piston rod 3 is provided with an extended detection rod 3a. The upper rod end 9 of the cylinder 1 is provided with a hole 10 that does not interfere with the detection rod 3a and a screw 12 for attaching the reflective photoelectric switch 11. The reflective photoelectric switch 11 is configured to detect that the piston 4 is in the return state by utilizing the difference between the distance L _and the return of the cylinder stroke.

13 and 14 are ports connected to a compressed air source.

[Operation] As is clear from the above configuration, the present invention supplies compressed air to the chamber A from the upper port 13 provided in the cylinder 1.
When the air is forced into the piston 4a, it acts on the upper part of the piston 4a and pushes it down, and on the other hand, a part of the air sent into the A passes through a passage provided in the piston rod 3 and enters the B chamber, acting on the top surface of the piston 4a and pushing it down. The tip attached to the point holder 8 via the piston rod 3 by these pistons 4, 4a pressurizes the product and energizes it to weld it. At this time, the detection rod 3a extending from the upper part of the piston rod 3 is separated from the reflective photoelectric switch 11 by a distance L. Once welding is finished,
When compressed air is forced into the A chamber from the lower pot 14 provided in the cylinder 1, the air above the piston in the A chamber is released, the compressed air acts on the lower surface of the piston 4 and pushes it up, and this piston 4 pushes the piston in the B chamber. 4a rises accordingly. At this time, the compressed air in chamber B passes through the passage and enters chamber A, and is discharged together, causing the pistons 4, 4a to rise. As the piston rises, the detection rod 3a extends from the piston rod 3.
rises within the hole 10 provided in the rod end 9, and becomes a distance L ₁ from the reflective photoelectric switch 11. Therefore, by utilizing this difference, the reflective photoelectric switch 1
1, it is detected that the piston 4 has risen from the pressurized state and is in the state at the time of instruction.

〔effect〕

As mentioned above, the present invention exposes the lower part of the piston rod of the cylinder into which the piston is slidably fitted, and attaches a point holder to the tip of the piston rod with a tip attached via a shank using a screw adapter, and lowers the piston rod from the piston. A welding cylinder that pressurizes and energizes the product with a tip at the tip to perform welding, and is equipped with a detection mechanism that features a built-in reflective photoelectric switch that detects the movement of the piston in the cylinder head. A reflective photoelectric switch is installed in the head of a conventional welding cylinder, and the return of the piston can be confirmed using the reflective photoelectric switch using the movement of the piston, that is, the stroke difference of the piston rod. , there is no malfunction due to magnetic force unlike conventional detection. In addition, since the reflective photoelectric switch is attached to the rod end of the cylinder head, it is effective regardless of the space available and there is no risk of malfunction due to welding spatter.

[Brief explanation of the drawing]

In the drawings, Figures 1 to 4 show conventional examples. Figure 1 is a front view of a conventional cylinder, and Figure 2 is a detection system in which a mitsu switch is installed on the opposite fixed side to detect the return of the piston of the cylinder. Figure 3 is a front view of a cylinder in which the presence or absence of welding is detected by applying a voltage and the current value, and Figure 4 is a front view of a cylinder in which the presence or absence of welding is detected using a magnet installed on the piston and a magnetic switch attached to the cylinder. The front view, Figures 5 and 6 are one embodiment of the present invention, Figure 5 shows the internal structure of the cylinder, the front view shows the state when the piston rod is out and the product is pressurized, and Figure 6 shows the state after welding. It is a front view when a piston returns to the time of starting. 1...Cylinder, 2...Partition plate, 3...Piston rod, 3a...Detection rod, 4, 4a...Piston, 5...Tip, 6...Shank, 7...Screw adapter, 8...Point holder , 9... Rod end, 10... Hole, 11... Reflective photoelectric switch, 12... Screw, 13, 14... Port, A,
B...room.

Claims (1)

[Scope of utility model registration request] The lower part of the piston rod of the cylinder into which the piston is fitted is exposed from the cylinder, and a point holder with a tip attached to it via a shank with a screw adapter is attached to the tip of the piston rod. In a welding cylinder that performs welding by pressurizing and energizing, an extended detection rod is provided at the top of the piston rod, and a reflective photoelectric switch is installed at the cylinder head to detect movement of the piston and a hole that does not interfere with the detection rod. A welding cylinder with a built-in detection mechanism.