JPH0433544B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for automatically setting welding conditions for a covered arc welding rod, and in particular, when a covered arc welding rod is clamped with a welding holder, the welding power source This invention relates to a method of automatically setting appropriate conditions according to the diameter.

[Conventional technology]

Conventionally, when performing manual welding using this type of covered arc welding rod, first select a coated arc welding rod of the appropriate type and rod diameter depending on the plate thickness of the workpiece, groove conditions, and welding posture. Clamp it to the welding rod holder. Next, the welding machine is adjusted to provide welding conditions suitable for the welding rod. For example, with a movable core type AC arc welding machine commonly used for manual welding, you must go to the welding machine's installation location, rotate the current adjustment handle to move the movable core, and set the conditions to the appropriate welding current value. . If equipped with a remote current adjustment device, operate the switch to increase or decrease the current,
In the case of using a wireless type rectifier (short circuit), the current is increased or decreased by bringing the short circuit into contact between the welding rod holder and the object to be welded in the direction of increasing or decreasing the welding current. Moreover, the degree of this increase or decrease is generally determined by the operator's intuition by appropriately generating arcs.

[Problems to be solved by the invention]

In the above-mentioned work, even though the welding current value actually set is specified in a work standard, it is ultimately set arbitrarily by the will of the worker in most cases. As a result, the welding current tends to become excessive, and defects such as bubbles (blowholes, pits, etc.) and undercuts are likely to occur in the welded part. This is because the welding operator's will to increase the current to improve welding efficiency and the on-site situation that adjusting the welding current is troublesome. Therefore, when non-destructive inspection (X-ray inspection, etc.) of welds is performed, air bubbles are often found inside the weld, and it is necessary to remove the weld bead by gouging etc. and re-weld, which may affect the quality of the weld. This will actually reduce the welding efficiency. Although it is relatively rare compared to excessive welding current, cases of insufficient welding current are also seen, resulting in welding defects such as insufficient penetration and overlap.

The present invention was devised to solve the above problems, and eliminates the causes of bubbles and undercuts caused by excessive welding current, and insufficient penetration and overlap caused by too small welding current, thereby improving welding quality and welding efficiency. The purpose of the present invention is to provide a method for automatically setting welding conditions for covered arc welding, which improves the performance of shielded arc welding.

[Means for solving problems and their effects]

In order to achieve the above object, the present invention provides a detection means for transmitting an electric signal to a welding machine based on a change in diameter when a covered arc welding rod is clamped to the welding rod holder, and the welding machine is characterized by automatically setting appropriate welding conditions and continuing high-quality welding work.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a welding apparatus according to a first embodiment of the present invention, in which an AC arc welding machine is used as the welding machine. In the figure, 1 is a coated arc welding rod, 2 is a welding base material, 3 is an AC arc welding machine,
4 is a spring clamp type welding rod holder for clamping the coated arc welding rod 1, and 5 is a spring for clamping the holder 4. The AC arc welding machine 3 houses a drive motor 7 for moving the movable iron core 6 of the AC arc welding machine and three sets of limit switches for stopping the movement of the movable iron core 6. (Figure 1 shows 8
Only one set of limit switches a and 8b is shown, and the others are omitted. ) Note that 9 is a welding cable that supplies power from the AC arc welding machine 3 to the coated arc welding rod 1, 10 is a control cable of the welding cable 9, 11 is a lead wire from the welding base material 2,
Both are connected to the secondary terminal 15 or welding terminal 16 of the AC arc welding machine 3.

FIG. 2 is a sectional view of a welding rod diameter change detection means attached to the spring clamp type welding rod holder 4. As shown in FIG. Potentiometer 12 as rod diameter detector
Both ends are hollow synthetic resin pipes 12M, 12N
The pipes are fixed to one end of each pipe, and the other ends of these pipes are fixed to the grip portion 4a of the welding rod holder 4, respectively.
A lead rod 12C 1 connected to the variable contact is connected to the insulator 12 so that the movable contact of the potentiometer ₁₂ can slide on the resistive element of the potentiometer.
It is fixed to the clamping part 4C of the welding rod holder 4 to which one end 5b of the spring 5 is fixed via L.

The above pipe 1 from both ends of potentiometer 12
Lead wires 12a, 1 with 2M and 12N inserted through them respectively
2b and the lead wire 12C connected to the lead rod _12C1 are connected to a meter relay 13, as shown in FIG. Since the meter relay 13 has welding rods of 1.2, 2.0, 2.6, 3.2, 4.0, 6.0, and 8.0 mmφ, it is equipped with a voltage setting device corresponding to the diameter of 2.6 mmφ, 3.2 mmφ, and 4.0 mmφ, and these settings can be adjusted. The voltage signal and the detected voltage signal of the potentiometer 12 are compared and calculated, and as a result, the predetermined set voltage corresponding to the welding rod of the selected diameter value is sent to the sequence control circuit 14 as a controller of the welding machine. do. The output signal of the sequence control circuit 14 is applied to the drive motor 7 that moves the movable iron core 6 of the AC arc welding machine 3. On the other hand, the output signal of the sequence control circuit 14 has a diameter of 2.6 mmφ and 3.2 mm.
It is applied to limit switches 17a, 17b, and 17c that stop the movement of the movable iron core 6 so that a welding current suitable for the welding rod of φ and 4.0 mmφ can be selected.

With the above configuration, the diameter is 2.6mmφ, 3.2mmφ,
Of the 4.0mmφ coated arc welding rods, 2.6 in use
When replacing mmφ welding rod 1 with 3.2mmφ welding rod,
The potentiometer 12 shown in FIG.
Diameter 3.2mmφ from a voltage value signal corresponding to 2.6mmφ
Sends a voltage value signal corresponding to the meter relay 13 to the meter relay 13.
Compare and calculate the voltage signal corresponding to the diameter of 3.2 mmφ to the drive motor 7 via the sequence control circuit 14, and draw out the movable iron core 6 of the AC arc welding machine 3. move it to At the same time, the sequence control circuit 14 sends a signal to the limit switch 17b to stop the movable iron core 6, and the arc welder 3 outputs a welding current suitable for the welding rod 1 with a diameter of 3.2 mm.

Note that the mounting method of the potentiometer 12 is not limited to the above embodiment, and any method may be used as long as the variable terminal of the potentiometer 12 can slide on the resistor according to the elasticity of the spring 5.

In addition, in this embodiment, the coated arc welding rod 1
Although the potentiometer 12 is used as a means for detecting a change in the diameter of the motor, a differential transformer 22 may be used instead, as shown in FIG. The differential transformer 22 has a secondary winding 22c with an equal number of turns,
22d are connected in series in opposite directions, and the iron core 22a is configured such that when the primary winding 22b is excited by the AC power source, the output of the secondary winding becomes zero. Moreover, it is set to be movable. This iron core 22a may be attached to a spring clamp type welding rod holder in the same way as the potentiometer 12a.

Furthermore, although the spring clamp type welding rod holder 4 is used as a clamping means for the coated arc welding rod 1 in this embodiment, a screw type holder may be used instead. The screw-in type holder clamps the welding rod with a presser rod, and the degree of clamping can be adjusted by screwing in the holder. Therefore,
By changing the stroke of the holding rod, welding rods of different diameter values can be clamped.
The variable terminal of the potentiometer can be moved in response to changes in the stroke of the presser bar.

Next, a second embodiment of the present invention will be described.

In the first embodiment, it may be possible to use many types of coated arc welding rods with different diameters, but in the second embodiment, the number of coated arc welding rods with different diameters is limited to two types, for example, 3.2 mmφ and 4.0 mmφ. This is the case. In the second embodiment, the arc welding machine normally
The welding rod is supplied with 120 amperes, which is optimal for a 3.2 mmφ coated arc welding rod.
Only when a 4.0mmφ coated arc welding rod is clamped to the welding rod holder, the contacts installed in the spring of the welding rod boulder are activated, and the signal is sent through a sequence circuit to move the movable core of the AC welding machine. In addition to the drive motor, the output signal of the sequence circuit described above is applied to the limit switch to stop the movement of the movable core, and the arc welder uses a welding power source that is optimal for a 4.0 mmφ coated arc welding rod.
Outputs 170 amps.

Therefore, since the second embodiment is an on-off type, the structure is extremely simple.

Next, a third embodiment of the present invention will be described.

The first and second embodiments use an AC arc welding machine as the welding power source, but the third embodiment uses an engine-equipped welding machine, an electric power generation welding machine, a rectifier/thyristor, and a transistor type DC arc welding machine as the welding power source. An inverter type arc welding machine is used. In the welding machine of the third embodiment, the output current or, in the case of a generator, the excitation circuit is adjusted by electronically controlling the output current using an electronic circuit. This example is the first
As explained in the embodiment, the detection means attached to the welding rod holder detects the change in the diameter of the clamped covered arc welding rod, and the detected electric signal is converted to drive the thyristor gate circuit of the welding machine. The present invention is characterized in that a signal is formed to control the conduction angle of the gate circuit.

〔Effect of the invention〕

From the above explanation, according to the present invention, appropriate welding conditions are automatically set just by the welding operator clamping the covered arc welding rod to the welding rod holder, so that the welding machine installed at a distance from the working position can There is no need to go all the way to adjust the setting conditions, and even when using a remote current adjustment device, there is no need for the operator to adjust the conditions based on his or her intuition. Further, it is possible to prevent the tendency of excessive current settings based on the operator's judgment, and the operator does not need to be extra careful.

In this way, by automatically setting appropriate welding conditions, welding defects such as bubbles and undercuts due to excessive welding current, insufficient penetration and overlap due to insufficient welding current are eliminated, welding quality is improved, and welding quality is improved. Welding efficiency can be improved, and the rod diameter is selected by comparing the detection signal from the rod diameter detector with multiple preset voltages corresponding to the diameters of the various coated arc welding rods to be used. Even if the value of the detection signal varies somewhat depending on the length of the cable connecting the rod diameter detector and the welding machine main body, the rod diameter can be accurately determined.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a welding apparatus according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a diameter change detection means of a welding rod attached to a spring clamp type welding rod holder.
FIG. 3 is a connection diagram showing a schematic configuration of the first embodiment of the present invention, and FIG. 4 is a configuration diagram of a differential transformer used in the first embodiment of the present invention. 1...Coated arc welding rod, 2...Welding base material, 3
...AC arc welding machine, 4...Welding rod holder, 5
...Spring, 6...Movable iron core, 7...Drive motor, 8a, 8b...Limit switch, 12...
...Potentiometer, 12M, 12N...Synthetic resin hollow pipe, 13...Meter relay, 14...
...Sequence circuit, 14...Sequence circuit, 1
7a, 17b, 17c...Limit switch, 2
2...Differential transformer.

Claims (1)

[Claims] 1. When a covered arc welding rod is clamped to a welding rod holder, a voltage value detection signal corresponding to the diameter of the covered arc welding rod is obtained from a rod diameter detector attached to the welding rod holder, and various types of signals to be used are obtained. The above detection signal is compared with a plurality of preset voltage values set in accordance with the diameter of the covered arc welding rod, and the set voltage value selected in accordance with the value of the above detection signal is controlled by mechanical control using a movable iron core. Automatic welding conditions for a coated arc welding rod, characterized in that the welding current is supplied to a controller for controlling the welding current by electronic control using a semiconductor device, and the controller controls the welding current according to the set voltage value. Setting method.