JPH0329015Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a welding table drive device used for automatic TIG (tungsten inert gas arc) welding and automatic carbon dioxide arc welding.

(Prior Art) This type of welding table driving device uses a table driving machine to move a movable table that holds a welding torch along a welding line of a welding base material. Here, conventional automatic positioning devices for the movable table include (1) a device that is provided with a limit switch and a dog to detect the stop position of the movable table, and stops the movable table using an output signal from the limit switch; A detector such as an inductor that outputs a signal proportional to the linear movement distance of the table or an encoder that outputs a signal proportional to the rotation angle of the feed screw of the moving table is provided, and this is combined with a servo motor to detect the above-mentioned detector. A device is known in which a counter counts the electrical signals from the servo motor, and when a preset count value is reached, a control signal is sent to the servo motor drive circuit to decelerate and stop the servo motor under digital control.

Although the device described in (1) above is inexpensive, it suddenly stops the drive motor while it is rotating at high speed, so the accuracy of stop positioning of the moving table deteriorates due to the influence of the large inertia of the drive motor. Also,
Adjusting the position of the dog is troublesome. In addition, although the device described in (2) above has good positioning accuracy of the moving table, the detector requires a two-phase output in order to utilize the phase difference, and the counter can count by either addition or subtraction. Since it requires a counter and uses a servo mechanism, it is complex and expensive. Furthermore, servo motor drive circuits are prone to malfunction due to electrical noise, and in TIG automatic welding in particular, high-voltage, high-frequency current is generated at the time of arc start, so there is a high risk of malfunction due to induced disturbances.

(Purpose of the invention) This invention was made to solve the above-mentioned problems of the prior art.It has good positioning accuracy of the moving table, and also eliminates the need for a two-phase output detector, addition/subtraction counter, or servo mechanism. It is an object of the present invention to provide a welding table drive device that is inexpensive, has a simple structure, and is free from malfunction due to high frequencies.

(Structure of the invention) In order to achieve the above object, this invention provides a movable table on a ball nut, attaches a welding torch to one arm of the movable table via a torch holder, and attaches a dowel to the other arm. a first detector corresponding to the dowel and provided in front of the welding start position, which detects the deceleration start position by coming into contact with the dowel, stops the table driving machine, and starts deceleration of the movable table; Then, while the movable table is decelerating, a welding start position detecting dowel for detecting the welding start position of the movable table is attached to the axial tip of the table feed screw in front of the welding end position, and facing the dowel. a second detector installed at a position that detects the dowel and activates the brake of the table driving machine; and when this counted value matches a value corresponding to a length slightly shorter than a preset welding length, it is activated to stop the table driving machine and start decelerating the movable table. A first counter attached to the axial tip of the table feed screw located in front of the welding end position is reset when the movable table reaches the welding start position and counts the distance traveled by the movable table. and when the counted value matches a value corresponding to a preset welding length during deceleration of the table driving machine, the table located in front of the welding end position activates the brake of the table driving machine. This configuration includes a second counter attached to the axial tip of the feed screw, and by applying the brake during deceleration of the table drive machine, the movable table can be accurately positioned to stop, and a complex servo mechanism can be controlled. making it unnecessary.

(Embodiment) FIGS. 1 to 4 show a welding table driving device according to an embodiment of this invention, and FIG. 4 is an electric circuit diagram.

In FIG. 1, reference numeral 1 denotes a table drive machine consisting of a drive motor, which rotates a table feed screw (ball screw) 5 supported by bearings 3 and 4 via a gear device 2. Further, an electromagnetic brake 6 is attached to the rear shaft end of the table driving machine 1. A ball nut 7 is engaged with the table feed screw 5 and is moved in the axial direction by the rotation of the table feed screw 5. A movable table 8 is attached to the ball nut 7, a welding torch 11 is attached to one arm 9 of the movable table 8 via a torch holder 10, and a welding torch 11 is attached to one arm 9 of the movable table 8.
2 is provided with a dog 14 corresponding to a limit switch (first detector) 13 that detects a deceleration start position before the welding start position. At the tip of the table feed screw 5, there is a dog 1 for detecting the welding start position.
5 and a moving distance counting dog 17 are fixed, and a proximity switch (second detector) 16 and a proximity switch 18 are arranged opposite to these dogs 15 and 17, respectively. Welding start position detection dowel 15
Both of the moving distance counting dowels 17 are formed of magnetic metal, such as mild steel, into a convex shape, and are provided at positions facing the detection surface of the proximity switch. One dowel 15 for detecting the welding start position is installed in the same rotational plane as shown in the figure, and a plurality of dowels 17 for moving distance counting are installed in the same rotational plane as shown in the figure in consideration of position detection accuracy. It was established.

On the other hand, the proximity switches 16 and 18 are provided at positions facing the dowels 15 and 17, and when these dowels approach the detection area specific to the proximity switches, the proximity switches 16 and 18
It is a static switch (sensor) that reverses the electrical output from ON to OFF or from OFF to ON. 1
Reference numeral 9 denotes a welding base material, which is welded along a welding line 20 thereof. Although not shown, a guide rail is provided to prevent the movable table 8 from rotating freely, and a welding wire supply device is also provided as required.

While FIG. 1 above shows the state of the movable table 8 before starting, FIG. 2 shows the movable table 8
FIG. 3 shows a state in which the moving table 8 has moved to the welding start position, and FIG. 3 shows a state in which the moving table 8 has moved to the welding end position.

FIG. 4 shows the electric circuit of the welding table drive device configured as described above, in which 1 indicates the table drive device;
6 is an electromagnetic brake, 13 is a limit switch (first detector), 16 is a proximity switch (second detector), and 18 is a proximity switch for the counter, which are given the same numbers as in Figures 1 to 3. There is. 21 is a power supply, 22 is a start switch, and 23 is a main switch. 24, 25, 26 and 27 are relays, and 24a and 24b, 25a, 26a and 27a and 27b are their contacts, respectively. 28
and 29 are electronic first and second preset counters, which are designed to output a signal when the final count is set in advance and the final count reaches that count, and each is reset at the start of welding. , the signal is set to be output at the deceleration start position and the welding end position before the welding end position. In addition, the preset counter 29 has a built-in DC power supply, and the counter proximity switch 18
It also serves as a power source. Resistor 31 is proximity switch 1
8 load resistance. 28a and 29a and 29
b are preset counters 28 and 29, respectively.
This is the point of contact. 30 is a contact of an arc occurrence detection relay (not shown) provided in the welding machine, and the contact 30 is closed while an arc is generated between the welding torch 11 and the welding base metal 19 in FIG. There is. Here, FIG. 4 is for showing the principle of this invention, and shows a circuit for returning the movable table 8 from the state shown in FIG. 3 to the position shown in FIG. 1 by reversing the table driving machine 1, and a TIG welding The control circuitry for the wire feeding device required for this is not shown.

Next, the operation of the welding table drive device shown in FIGS. 1 to 3 will be explained based on the electric circuit shown in FIG. 4.

When the start switch 22 shown in FIG. 4 is pressed while the moving table 8 shown in FIG. When closed, the table driving machine 1 rotates, and the moving table 8 shown in FIG. 1 moves along the table feed screw 5.
When the movable table 8 further moves to the position shown in FIG. 2, the dog 1 provided on the movable table 8
4 presses the limit switch (first detector) 13 to make it conductive, the limit switch 13 shown in FIG. The drive machine 1 starts decelerating. While the table driving machine 1 is decelerating, the welding start position detection dog 15 shown in FIG.
6 is detected, the proximity switch 16 shown in FIG. 4 closes and the relay 26 operates, and accordingly, its contact 26a closes and the electromagnetic brake 6 operates, causing the table drive machine 1 to stop suddenly. As a result, the welding torch 11 attached to the moving table 8 in FIG.
stops at the welding start position. In order to obtain an accurate stop position, the limit switch 13 is provided at a position where the deceleration is performed several mm before the stop position.

Next, a relay (not shown) is activated manually or by a signal from the proximity switch 16 to reset the preset counters 28 and 29 in FIG. 4, and then the welding machine (not shown) is operated. An arc is generated between the welding torch 11 and the welding base material 19 shown in FIG. When an arc occurs, contact 3 of the arc detection relay (not shown) in the welding machine is
0 is closed and relay 27 is activated. This relay 27 closes the contact 27a and opens the contact 27b, so the electromagnetic brake 6 becomes ineffective and the table drive machine 1 restarts. In FIG. 2, when the table driving machine 1 rotates, the movable table 8 starts to move, and the welding torch 11 moves along the welding line 20 while performing arc welding. In addition, since the moving distance counting dog 17 rotates at the same time as the table driving machine 1 rotates, the counter proximity switch 18 is turned on and off.
A pulse signal is generated, which is counted by preset counters 28 and 29 in FIG.

When the moving table 8 in Fig. 2 moves to the deceleration start position before the welding end position, the count value of the preset counter 28 for counting the deceleration position in Fig. 4 matches the preset value, and the contact point 2
Since 8a is open, the relay 24 will no longer work. When the relay 24 stops working, one contact 24
a opens and the self-holding of the relay 24 is released, and the other contact 24b also opens, so the power supply to the table drive machine 1 is stopped and this table drive machine 1
starts decelerating. While the table driving machine 1 is decelerating, the count value of the preset counter 29 for counting the welding end position matches the preset value, one of the contacts 29a closes, the electromagnetic brake 6 works, and the third The moving table 8 suddenly stops at the position shown in the figure. Here, the preset counter 29 in FIG. 4 is set so that the deceleration is performed several mm before the stop position in order to make the stop position accurate, as in the case of starting welding. Simultaneously with the above-mentioned stop, the other contact 29b of the preset counter 29 sends a signal to the welding machine (not shown) to stop the hair arc, and the arc is stopped and welding is completed.

To return the movable table 8 from the position shown in Fig. 3 to the position shown in Fig. 1 after welding is completed, turn off the power to the preset counters 28 and 29, and then reverse the table driving machine 1 by operating a manual switch. Just let it happen.

In the above configuration, when stopping the moving table 8 at the welding start position and the welding end position,
The motor of the table drive machine 1 is stopped and decelerated several mm before the above-mentioned stop position, and the electromagnetic brake 6 is applied during the above-mentioned deceleration to bring the movable table 8 to a sudden stop, so the inertial force of the drive machine causes an adverse effect. It is less susceptible to damage, and the accuracy of the stop position of the moving table 8 is good.
Further, the preset counters 28 and 29 may be used only for addition or subtraction, and since they do not utilize phase difference, the proximity switches 16 and 1
8 may also have a single-phase output, and since the table drive motor 1 does not use a servo motor, the structure is simple and inexpensive. Furthermore, since a servo motor drive circuit is not required, there is no malfunction due to electrical noise, and no special high frequency countermeasures are required.

In the above embodiment, the table driving machine 1 is naturally decelerated by stopping the power supply to the table driving machine 1, but it is also possible to provide a separate control device to gradually reduce the rotational speed of the motor. Therefore, forced deceleration may be performed.

(Effects of the invention) As explained above, according to this invention, the positioning accuracy of the moving table is good, and it is inexpensive and has a simple structure by eliminating the need for a two-phase output detector, addition/subtraction counter, or servo mechanism. Moreover, due to the high frequency, there is no risk of malfunction.

[Brief explanation of the drawing]

Figures 1 to 3 are perspective views showing one embodiment of this invention, with Figure 1 being a perspective view showing the movable table in a state before starting, and Figure 2 being a perspective view showing the movable table in the welding starting position. FIG. 3 is a perspective view showing the movable table at the welding end position;
FIG. 4 is an electrical circuit diagram of the same embodiment. 1... Table drive machine, 5... Table feed screw, 6... Electromagnetic brake, 7... Ball nut,
8...Moving table, 11...Welding torch, 13
...Limit switch (first detector), 16...
... Proximity switch (second detector), 18 ... Proximity switch for counter, 19 ... Welding base material, 20 ...
...welding line, 28...first counter, 29...second counter.

Claims (1)

[Scope of utility model registration request] A movable table that holds a welding torch is connected to a table drive machine, a table feed screw that is supported by a bearing and rotates via a gear device that transmits the driving force from the table drive machine, and a shaft that engages with the table feed screw. In a welding table drive device that moves a welding member along a welding line with a ball nut that moves in the direction, the above-mentioned moving table is provided on the ball nut, and a welding torch is attached to one arm of the moving table via a torch holder. At the same time, a dock is provided on the other arm,
a first detector corresponding to the dowel and provided in front of the welding start position, which detects a deceleration start position by coming into contact with the dowel, stops the table driving machine, and starts deceleration of the movable table; While the movable table is decelerating, a welding start position detection dowel for detecting the welding start position of the movable table is attached to the axial tip of the table feed screw in front of the welding end position, and the dowel is positioned opposite to the dowel. a second detector installed at the welding table to detect the dowel and actuate the brake of the table driving machine; and a second detector which is reset when the movable table reaches the welding start position and counts the distance traveled by the movable table. , and when this counted value matches a value corresponding to a length slightly shorter than a preset welding length, the welding operation is activated to stop the table driving machine and start decelerating the movable table. A first counter attached to the axial tip of the table feed screw located in front of the position is reset when the movable table reaches the welding start position, and counts the distance traveled by the movable table, and the table feed screw located in front of the welding end position which activates the brake of the table drive when this counted value matches a value corresponding to a preset welding length during deceleration of the table drive. A welding table drive device comprising: a second counter attached to an axial end portion of the welding table drive device.