JPH0233987Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a welding device that welds press-formed products that are intermittently sent out while moving a torch.

[Prior art]

In a manufacturing line that continuously shapes and feeds long objects such as pipes, objects to be welded are fed out continuously from beginning to end, and the feeding speed during the feeding period is constant and relatively low. Furthermore, the rise and fall changes in speed at the start and end of feed were also relatively small. Therefore, the welding current of the welding device used in such a manufacturing line does not change in response to changes in the feed speed of the welded object, which changes from time to time.

[Problem that the invention attempts to solve]

On the other hand, there are manufacturing lines in which objects to be welded are fed out intermittently, and in such manufacturing lines, the feed speed varies over a fairly wide range from "0" to a certain speed, and there are various feed speed patterns. do. Therefore, conventional welding equipment cannot cope with such changes in feed speed, and a problem arises in that a good weld finish cannot be obtained.

Therefore, the applicant previously proposed changing the welding current in response to the change in the feed rate to obtain a good welding finish. However, this proposal required complicated current pattern control.

The present invention was developed in view of the above-mentioned circumstances, and its purpose is to perform good welding on objects to be welded that are intermittently fed out without having to perform complicated current pattern control. The purpose is to provide welding equipment.

[Means to solve the problem]

Therefore, in the present invention, a discriminating means for discriminating between a feeding period and a stop period of the object to be welded, a feed amount detecting means for sending out the amount of feed of the object to be welded during the feeding period, and a reciprocating motion of the torch. a torch drive means for welding while moving the torch by the same amount as the feed amount during the stop period, and returning the torch to its original state within the next feed period while maintaining the arc after welding; The above-mentioned problem is solved by providing a control means for returning to the position.

[Effect]

The feed amount and stop period during the feed period of the welded object are detected, and the speed and welding current set on the welding equipment side based on the detected feed amount and stop period are used to set the same feed amount as the above feed amount during the stop period. Perform welding while moving the torch. After welding,
During the feeding period of the object to be welded, the torch is moved by the same amount as the feeding amount and returned to the original position while the arc is maintained. Repeat this action from now on. Therefore, it is not necessary to perform complicated current pattern control of the welding current, and it becomes possible to perform welding with a constant welding current, allowing welding to be performed with high precision and good reproducibility.

〔Example〕

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

The figure is a block diagram showing the configuration of this embodiment. In this figure, reference numeral 1 denotes a press molding device for press molding a hoop material 2 into a pipe shape. 1a, 1a are slitshears,
It is used to make cuts leaving a part of the workpiece intact. After welding, the cut portion allows the pre-less molded product to be easily separated, improving accuracy when manufacturing short pipes.

A feed mechanism (not shown) included in the press molding apparatus 1 transports the welded body 2a processed into a pipe shape to the right in the figure while being supported by the sizing rollers 3, 3.

On the other hand, the left end of the feed screw 4 is connected to the shaft of the motor 5, and the right end is supported by a bearing 6. Further, a movable part 7 is screwed onto the feed screw 4, an arm 8 is fixed to the movable part 7, and a torch 9 is attached to the arm 8.
Furthermore, a tachometer generator 5a for speed detection is connected to the feed screw 4. That is, when the feed screw 4 is rotated by the motor 5, the torch 9 reciprocates between the sizing rollers 3 and 3 along the workpiece 2a, and the rotational speed of the motor 5 at this time is detected by the tachogenerator 5a. It is composed of

In addition, a pair of rollers 10a, 10a are provided in front of the sizing roller 3 (to the right in the figure), facing each other with the object to be welded 2a in between. A rotary encoder 10 is attached to one shaft of the roller 10a. Therefore, the object to be welded 2a
The rotary encoder 10 rotates in conjunction with the feed of the welded object 2a, and outputs the number of pulses proportional to the amount of feed of the object to be welded 2a.

Next, the configuration of the control system will be explained.

The microprocessor 11 includes a period determining section, a feed amount counting section, an arithmetic section, and the like.

In the period determination section, the rotary encoder 10
By detecting the presence or absence of pulse input from
A period signal is output that distinguishes between a feeding period and a stopping period of the object to be welded 2a. This period signal is "0" during the stop period and "1" during the sending period.

In the feed amount counting section, the rotary encoder 1
The feed amount is counted by counting the number of pulses output from 0, and this feed amount data is
Write to a specified address in RAM12.

The calculation section obtains rectangular speed pattern data with a constant speed from the feed amount data. That is, the calculation section calculates and determines the time width of the rectangular speed pattern data so that the feed amount data and the integral value of the rectangular speed pattern data are equal. In this case, it goes without saying that the time width of the speed pattern data must be smaller than the stop period.

The microprocessor 11 has a D/A converter 14.
is connected. The converter 14 converts the speed pattern data into a speed command Vs of an analog signal, and supplies this speed command Vs to the motor control circuit 15.

The motor control circuit 15 includes an operational amplifier, a current amplifying transistor unit, etc., and the speed command Vs is input to one input terminal of the operational amplifier. The output voltage of the tachometer generator 5a is fed back to the other terminal. The output of this operational amplifier is current-amplified by a current-amplifying transistor unit and supplied to the motor 5. In this case, the motor 5 (DC servo motor) is configured to rotate forward or reverse.

On the other hand, the microprocessor 11 applies the period signal Is output from the period determining section to the welding power source 17 (the welding power source of the high-frequency pulse arc welding machine).

The welding power source 17 includes an arithmetic circuit, a direct current output section that outputs a direct current based on a current command of the arithmetic circuit, a high frequency pulse current output section that outputs a high frequency pulse current, and a high frequency pulse current output section that outputs the direct current and the high frequency pulse current. It is composed of a current control circuit (not shown) that superimposes the current and supplies the superimposed current to the torch 9.

In the welding power source configured in this way, when the period signal Is is "1" (corresponding to the feeding period),
An arc holding current is output, and when it is "0" (corresponding to a stop period), a constant welding current is output and supplied to the torch 9.

Next, the operation of this embodiment will be explained.

It is assumed that the object to be welded 2a, the torch 9, etc. are in the positions shown in the figure. First, start buttons (not shown) of the press molding device 1 and the welding device are pressed. In the press molding device 1, a hoop material 2 is press molded, and a welded object 2 is processed into a pipe shape.
a is sent out. On the other hand, in welding equipment,
An arc is formed between the tip of the electrode 9a of the torch 9 and the object to be welded 2a.

Hereinafter, the period for transporting the object to be welded 2a and the period for stopping it will be explained separately.

[Delivery period]

During this period, the microprocessor 11
The feed amount of the object to be welded 2a is detected, and the feed amount data is written into the RAM 12.
Furthermore, since the microprocessor 11 outputs the period signal "1", the welding power source 17 outputs an arc holding current, and the torch 9 maintains the arc at the initial position shown in FIG.

[Suspension period]

When the microprocessor 11 detects this stop period, the microprocessor 11 reads out the feed amount data written in the RAM 12, performs arithmetic processing on the arithmetic unit, and
Generate rectangular velocity pattern data. This speed pattern data is converted into a speed command Vs by the D/A conversion circuit 14, and the motor 5 moves the torch 9 at a constant speed based on this speed command Vs. Also,
Since the period signal Is to the welding power source 17 is "0", the welding power source 17 supplies a constant welding current to the torch 9 to perform welding. That is, during this stop period, the torch 9 moves at a constant speed to the left in the figure while performing welding with a constant current, and stops when it has moved by the same amount as the feed amount of the welded object 2a.

In this state, when the microprocessor 11 detects the next sending period, the microprocessor 11
is a speed pattern Vs with a polarity opposite to that of the stop period.
Output. Therefore, the torch 9 moves according to this speed pattern and returns to its original position. In addition,
During this time, the current command Is to the welding power source 17 is "1", so the arc is maintained but no welding is performed.
Furthermore, during the subsequent stop period, the same operation as described above, in which the torch is moved at a constant speed and welding is performed with a constant current, is repeated.

[Effect of idea]

As described above, according to the present invention, while the object to be welded is stopped, the torch is moved by the same amount as the feed rate of the object at the optimum constant speed set by the welding equipment, and Since welding is done with electric current,
There is no need to perform complicated current pattern control of welding current, and stable welding with high precision and good reproducibility can be achieved.

[Brief explanation of the drawing]

The figure is a block diagram showing the configuration of an embodiment of the present invention. 2a...Object to be welded, 4...Feed screw (torch drive means), 5...Motor (torch drive means), 5a
...Tachogenerator (torch driving means), 7...
...Movable body (torch driving means), 9...Torch, 1
0...Rotary encoder (feed amount detection means),
11...Microprocessor (discrimination means, feed amount detection means, control means), 12...Feed amount RAM (control means), 15...Motor control circuit (torch drive means, control means), 17...Welding power source (control means).

Claims (1)

[Scope of utility model registration request] In a welding device for welding objects to be welded that are transported while repeating a feeding period and a stop period, a discriminating means for discriminating between the feeding period and the stopping period, and a feed amount of the object to be welded during the feeding period. a feed amount detection means for detecting the amount of feed, a torch driving means for reciprocating the torch, performing welding while moving the torch by the same amount as the feed amount during the stop period, and maintaining the arc after welding. control means for returning the torch to its original position within the next feeding period.