JPH034458Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention detects the usage limit of the electrode tip in an automatic electrode shaping machine that uses a grinding tool to shape the electrode tip attached to the tip of the welding machine arm. The present invention relates to a use limit detection device for spot welding electrodes.

[Conventional technology]

The length of the spot welding electrode used in a spot welding machine decreases with use, so it must be replaced when its usable limit is reached.

Conventionally, in order to confirm the usage limit of an electrode, the welding machine arm to which the electrode tip is attached is rotated to a non-working area, and the amount of wear on the electrode tip is measured.

However, by visually measuring the usable limit as described above, it is not possible to accurately determine the length of the electrode tip, and if an electrode tip that is longer than the usable limit is used, water may leak from the tip of the electrode tip during welding. There is a problem that the tip of the electrode tip may crack or the welding quality may deteriorate. In order to solve this problem, Japanese Patent Publication No. 60-3907 has proposed a technique in which a detector is provided to detect the wear limit of the electrode tip.

[Problem that the invention attempts to solve]

However, in the above-mentioned conventional technology, the wear limit detector is provided near the grinding tool and the wear limit is detected by directly contacting the electrode tip, and therefore, the following problems occur.

Since grinding scum is scattered near the grinding tool during grinding of the electrode chip, this grinding scum may adhere to the wear limit detector and cause the detector to malfunction. In addition, since the wear limit detector itself is exposed to the outside, it is easy for dirt and dust to adhere to it in addition to grinding scum, making the detector extremely dirty.

To prevent the detector from malfunctioning and to eliminate contamination, it must be frequently cleaned and requires cumbersome maintenance work.

The positional relationship between the wear limit detector and the electrode chip directly affects the detection accuracy of the wear limit detector, so it is desirable to install the wear limit detector as close to the electrode chip as possible. If provided, when the robot arm is oscillated to move the electrode tip from the working position to the grinding tool position, the electrode tip may come into contact with the wear limit detector, causing false detection of the detector. be.

In view of the above problems, the present invention is a spot welding device that can detect the usage limit of an electrode tip while reliably preventing the detector from erroneous detection, contamination, or even damage. The purpose of the present invention is to provide an electrode usage limit detection device.

[Means for solving problems]

In order to achieve the above-mentioned problems, the present invention provides a mount equipped with a grinding tool on the shaping machine body so that it can be raised or lowered, and the mount is raised or lowered to attach the grinding tool to the electrode tip attached to the tip of the welding machine arm. In an automatic electrode shaping machine that grinds the tip of the chip by bringing a grinding tool into contact with it, rods are provided in parallel in the descending direction of the mount from the mount, and the tip of the rod is placed on a mount on which the sculpting machine body is mounted. The present invention is characterized in that a detection target is provided on a rod portion that extends into the interior of the mount and exists within the mount, and a detector that comes into contact with the detection target is provided within the mount and on the inner wall of the mount near the rod.

[Effect]

According to the present invention, when the grinding tool attached to the mounting base is raised or lowered to grind the electrode chip, the rod moves up and down integrally with the mounting base, so that the detection target piece provided on the rod is moved up and down. By setting a detector that operates in response to the current limit in advance at a position that corresponds to the usage limit of the electrode chip, when the detector outputs a detection signal, it is possible to know that the usage limit of the electrode chip is reached at that time. .

In this case, since the detected piece and the detector are installed in the pedestal on which the shaping machine body is mounted, the grinding scum produced by the grinding tool will not be scattered. In addition, since dirt and dust are less likely to adhere, erroneous detection can be prevented, and maintenance of the detector and the detected piece can be performed less frequently. Furthermore, since the detection target is attached to the rod (movable) side and the detector is provided to the inner wall of the mount (stationary side), it is easy to route the signal lines and wiring is easy.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an automatic electrode shaping machine, where A is the shaping machine main body, and a frame 2 is assembled on a pedestal 1. The frame body 2 is made up of a pair of upper and lower plate bodies 3 and 4 framed by a plurality of support posts 5. The frame body 2 is provided with a pair of guide rods 6, 6, and a metal fitting 7 guided by the guide rods 6, 6 is fixed to a piston rod 9 of a cylinder 8 installed upward on the pedestal 1. Reference numeral 10 denotes a grinding tool having the same configuration as the grinding surface of the tip of the electrode chip which is the object to be ground. This grinding tool 10 is mounted on a mounting base 11 protruding forward of the frame body 2, and as shown in FIG.
It is held at 2. The holder 12 is configured to rotate around a vertical axis by a rotary drive source 14 such as an air motor built in a case 13 that is integrally provided behind the mount 11.

The case 13 is attached to the metal fitting 7 by a fitting 15. Therefore, cylinder 8
When the piston rod 9 is moved up and down by operating the piston rod 9, the mounting base 11 is moved up and down together with the case 13 within a certain range. The lifting and lowering at this time is performed accurately because the metal fitting 7 is guided by the guide rods 6, 6, and the grinding tool 10 attached to the mount 11 is reliably moved up and down along a fixed path without wobbling laterally. Further, the cylinder 8 is capable of moving in and out in two steps, and when it is set at the neutral position shown in FIG. The electrode chips 52 and 53 thus formed are allowed to be carried into both the upper and lower sides of the grinding tool 10 by the rotation of the arms 50 and 51.

Reference numeral 17 indicates a chip holding mechanism, which holds the upper and lower electrode chips 52 and 53 at opposing positions of the grinding tool 10, and includes a fixed claw 18 forming a U-shape in side view, and a fixed claw 18 on the upper side. It consists of an upper movable claw 19 provided horizontally opposite to the lower movable claw 18, and a lower movable claw 20 similarly provided horizontally opposed to the fixed claw 18 on the lower side. A recess is formed in the central portion of both fixed claws 18 facing the movable claws 19 and 20, and a chip receiving portion 24 is formed.

On the other hand, the upper movable claw 19 and the lower movable claw 20 are
As described above, they are attached to a rotary body 28 that is rotatably installed on the support rod 22 with their distal ends facing the fixed claws 18, respectively, and the rotary body 28 is installed on the frame body 2. The upper movable claw 19 and the lower movable claw 20 are connected to the piston rod 25a of the movable claw driving cylinder 25 by a protruding rod 23, and as the piston rod 25a moves back and forth, the tips of the upper movable claw 19 and the lower movable claw 20 rotate about the support rod 22. The tip receiving portion 24 is closed and opened by moving the tip receiving portion 24.

33 is a mounting base 11 equipped with the grinding tool 10
The rod is connected to a fixture 15 that supports the cylinder 8, and is disposed in the same direction as the cylinder 8 moves in and out, that is, in the vertical direction, and extends inside the frame 1.
This rod 33 has ring-shaped rods at appropriate intervals.
The pieces to be detected 32a, 32b, 32c are attached by fixing means such as screws. On the other hand, on the inner wall of the pedestal 1 in the vicinity of the rod 33, there are three detectors 31 made of limit switches, for example, corresponding to the detection target pieces 32a, 32b, 32c.
a, 31b, and 31c are provided. The first detected piece 32a and the detector 31a are connected to the grinding tool 10.
are provided in such a positional relationship that they come into contact when they are located at the origin at an intermediate position in the vertical direction. Also, the second
The detected piece 32b and the detector 31b are located at a position where they come into contact when the upper electrode tip 52 is worn down to the limit of use when the upper electrode tip 52 is ground with the grinding tool 10. It is established in relation to The third detection piece 32c and the detection piece 31c are used when the lower electrode tip 53 is worn down to its usable limit when the lower electrode tip 53 is ground with the grinding tool 10. They are placed in such a position that they touch each other.

Note that when the origin position of the grinding tool 10 is detected by the first detected piece 32a coming into contact with the detector 31a, the electrode tips 52 and 53 attached to the welding machine arm are moved to the grinding position. The mounting base 11 is located at a position where it does not interfere with the rotation. Therefore,
The welding arm is rotated on condition that a signal is output from the detector 31a.

Next, the operation will be explained.

The upper and lower electrode chips 52 and 53 are carried into the position facing the grinding surface of the grinding tool 10 by the rotation of the arms 50 and 51 during a short period of time when they are not used for spot welding, and the shaping is completed within that time. By the rotation of the arms 50 and 51, it is carried out from the opposing position and subjected to welding again. If there is a request to shape a pair of upper and lower electrode chips 52, 53 at the same time, a chip holding mechanism 17 is provided for each of the electrode chips 52, 53 as in this embodiment, and It is advantageous if the grinding tool 10 is mounted on a mount that can be raised and lowered.
Further, when the electrode chips 52 and 53 are carried in and out, the upper movable claw 19 and the lower movable claw 20 are moved to the retracted position by the cylinder 25, and the carrying-in/out route is opened.

The arms 50 and 51 are integrally rotated to hold the upper and lower electrode chips 52 and 53 by the chip holding mechanism 17.
When the detection device 32 and the detector 31 are sandwiched between the detectors 31 and 31, the center detection target 32a comes into contact with the detector 31a, so that a detection signal is output from the detector 31a. In that case, the mounting base 11 is located at an intermediate position between the fixing claws 18 and the arms 50,
Allow 51 rotations.

Then, the electrode chips 52 and 53 are connected to the grinding tool 10.
When the upper electrode chip is carried to the opposite position and received by the chip receiving part 24 provided on the fixed claw 18, the movable claws 19 and 20 are rotated by the cylinder 25 in the direction approaching the fixed claw 18, and the upper electrode chip is moved. 5
Move to the pressing position where 2 is pressed. As a result, the electrode chips 52 and 53 are held by the chip holding mechanism 17.
It is held between the

When grinding the upper electrode tip 52 from this state, the mounting base 11, which has been set at the neutral position (origin position), is pushed up by the cylinder 8, and the grinding tool 10 is brought into contact with the upper electrode tip 52 in a fitted manner. Thereafter, the upper electrode tip 52 is ground by the action of the grinding tool 10 which is rotated by the rotary drive source 14 and shaped into a proper state. During grinding, the upper electrode tip 52 is held by the tip holding mechanism 17, so that the electrode tip 52 is prevented from vibrating or idling against the shank, and a stable processing state is maintained. . After shaping the lower electrode chip 53, the shaped upper electrode chip 52 is released from the chip holding mechanism 17 and used for spot welding. When the limit is reached, during the grinding process, the mounting base 11 into which the grinding tool 10 is fed rises, and finally the upper detection piece 32b fixed to the rod 33 is removed.
comes into contact with the detector 31b. If a detection signal emitted from the detector 31b due to this contact activates an alarm such as a buzzer, the operator can know that the upper electrode chip 52 has reached its usage limit, and can perform the work. Appropriate measures can be taken, such as interrupting the procedure and replacing the electrode. The same applies to the case of detecting the usage limit of the lower electrode chip 53; when the lower electrode chip 52 is being ground, when the detector 31c emits a detection signal from the lower detected piece 32c, the usage limit of the electrode chip 53 is detected. You can know that.

As described above, in this example, the three detected pieces 32 are attached to the rod 33 linked to the mounting base 1 equipped with the grinding tool 10.
Three detectors 31 are fixed to the pedestal 1 of the main body of the shaping machine in correspondence with the grinding of the electrode chips 52, 53, and at the same time the wear amount of the chips can be detected to know the limit of use.

[Effect of idea]

As explained above, the present invention has a mounting base for servicing the grinding tool that can be moved up and down on the shaping machine body, and the mounting base moves up or down to bring the grinding tool into contact with the electrode tip attached to the tip of the welding machine arm. In an automatic electrode shaping machine that grinds the tip of the chip, rods are provided in parallel from the mounting base in the downward direction of the mounting base, and the tips of the rods are inserted into the pedestal on which the shaping machine body is mounted. The detection piece is provided on the extended rod portion that exists within the pedestal, and a detector that comes into contact with the detection piece is provided on the inner wall of the mount near the rod inside the pedestal, resulting in the following effects.

The detected piece and the detector are separated from the grinding tool and are installed inside the mount, which prevents the grinding gas generated when grinding the electrode chip from adhering to it, or from becoming contaminated with dirt or dust. can. Therefore, erroneous detection by the detector can be prevented, and the frequency of cleaning the detector can be reduced.

Further, since the detector and the detection piece are inside the frame, they do not come into contact with the electrode chips, and therefore the detector and the detection piece can be effectively protected from damage.

Furthermore, since the mount itself serves as a dustproof cover for the detection target piece and the detector, there is no need to provide a separate cover body, contributing to the simplification of the configuration.

In addition, since the detector is provided on the inner wall of the pedestal, it is easy to route signal lines and wiring.

[Brief explanation of drawings]

Fig. 1 is a partially sectional side view showing an automatic electrode shaping machine according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line X-X in Fig. 1, and Fig. 3 shows a grinding tool installed. FIG. 3 is an enlarged plan view showing the main parts of the mounting base. A...Main body of shaping machine, 8...Cylinder, 10...
Grinding tool, 11...Mounting base, 14...Rotary drive source, 17...Chip clamping mechanism, 18...Fixed claw,
19... Upper movable claw, 20... Lower movable claw, 22
...Support rod, 25...Cylinder, 31a, 3
1b, 31c...detector, 32a, 32b, 32
c...Detected piece, 33... Rod, 50, 51...
...Arm, 52, 53... Electrode chip.

Claims (1)

[Claims for Utility Model Registration] (1) A mount for servicing the grinding tool is provided on the shaping machine body so that it can be raised or lowered, and the mount is raised or lowered to perform the grinding on the electrode tip attached to the tip of the welding machine arm. In an automatic electrode shaping machine that grinds the tip of the chip by bringing a tool into contact with it, rods are provided in parallel from the mounting base in a downward direction of the mounting base, and the shaping machine main body is mounted on the tip of the rod. A spot characterized in that a detection piece is provided on a rod portion that extends into the interior of the mount and exists within the mount, and a detector that comes into contact with the detection piece is provided on the inner wall of the mount near the rod within the mount. Usage limit detection device for welding electrodes. (2) There are three pieces to be detected and three detectors. The first piece to be detected and the detector detect the origin position of the mounting base, and the second piece to be detected and the detector detect the origin position of the mounting base. A request for registration of a utility model characterized in that the third detection piece and the detector are configured to detect the usage limit of the upper electrode chip, and to detect the usage limit of the lower electrode chip using the third detection piece and the detector. A usability limit detection device for a spot welding electrode according to item 1.