JP2566456Y2 - Consumable electrode type arc welding machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a consumable electrode type arc welding machine applied to perform arc welding using a consumable electrode wire and a filler wire.

[0002]

2. Description of the Related Art Conventionally, an example of this kind of consumable electrode type arc welding machine has been developed and proposed in Japanese Patent Application Laid-Open No. 3-275280. In this conventional arc welding machine, as shown in FIG. 5, a consumable electrode wire 1a for generating an arc 8 and a filler wire 1b for insertion into a molten pool 10 are arranged side by side with each other. Wire 1
A and the filler wire 1b are configured such that the current directions supplied from the welding power source 2E are opposite to each other (arrows a and b).

According to such an arc welding machine, since the filler wire 1b can be melted by the heat of the molten pool 10, the amount of electric power supplied to the consumable electrode wire 1a, that is, the heat input at the time of welding can be greatly increased. Instead, it is possible to increase the melting rate of the entire wire. Therefore, there is an advantage that even if the welding current is increased, even if it is an aluminum alloy or the like which is liable to cause puckering or welding distortion, welding with high work efficiency can be performed without causing such problems. When the directions (arrows a and b) of the current flowing through the two wires 1a and 1b are opposite, the wires 1a and 1b
The magnetic field generated around each part 1b generates a repulsive force, and the arc 8 is appropriately pushed forward (in the direction of arrow B), so that the filler wire 1b is melted by the arc 8 even when the two wires 1a and 1b are brought close to each other. Spattering is also eliminated as much as possible. Therefore, the filler wire 1b can be provided close to the consumable electrode wire 1a, and accordingly, the insertion into the molten pool 10 can be appropriately performed.

[0004]

However, in the above method, since the wires 1a and 1b need to be approached at a narrow interval of, for example, about 4 to 8 mm, the bending habits of the wires 1a and 1b, etc. Due to both wires 1
a and 1b may contact each other. It is difficult to prevent such contact only by the repulsive force of the magnetic field for controlling the arc 8. On the other hand, since the wires 1a and 1b are configured so that currents in opposite directions flow, if a short circuit occurs due to the contact, an extremely large current will flow through these wires. As a result, conventionally, there has been a danger that the welding power supply breaks down due to the contact between the wires or an accident occurs due to overheating of the welding power supply.

The present invention has been proposed in view of the above points, and is intended to prevent a situation in which an excessive current flows through both the consumable electrode wire and the filler wire due to an accidental contact between the two wires. However, an object of the present invention is to provide a consumable electrode type arc welding machine which is excellent in safety and does not cause a failure such as a failure of a welding power source.

[0006]

SUMMARY OF THE INVENTION A consumable electrode type arc welding machine according to the present invention, proposed to achieve the above object, comprises:
A consumable electrode wire and a filler wire for insertion into the molten pool are arranged side by side with each other, and both the consumable electrode wire and the filler wire are configured such that currents supplied from a welding power supply flow in opposite directions. A consumable electrode type arc welding machine, wherein current detecting means for detecting a current value flowing through the filler wire, and a current value detected by the current detecting means is a predetermined current value set in advance. Power supply control means for turning off the welding power source when the time exceeds the predetermined time and the excess time reaches a predetermined time.

[0007]

In the consumable electrode type arc welding machine according to the present invention characterized by the above-described structure, the consumable electrode wire and the filler wire come into contact with each other and a short circuit occurs between the two. When the amount of current flowing through the filler wire exceeds a preset current value and the excess time exceeds a predetermined fixed time, the power supply control means operates to turn off the welding power supply. Therefore, it is possible to avoid a situation in which an excessive current is continuously supplied to the consumable electrode wire and the filler wire thereafter, and the failure of the welding power source and the like are appropriately prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a consumable electrode type arc welding machine according to the present invention will be described below. FIG. 1 is an explanatory diagram showing a schematic configuration thereof. The arc welding machine shown in FIG. 1 includes a consumable electrode wire 1a for generating an arc, a filler wire 1b for inserting a tip into a molten pool, and welding power supplies 2a and 2b for supplying a predetermined current to both of the wires 1a and 1b. Detector 11 for detecting the current flowing through filler wire 1b, and timer circuit 1 for performing off control of welding power supplies 2a and 2b
2 and other devices described later.

Here, the consumable electrode wire 1a and the filler wire 1b are fed from the wire reels 3a, 3b to the feed roller 4a.
The gas nozzle 5 is provided so as to be able to be sequentially fed toward the base material by driving a and b, and each of its distal ends projects downward from the distal end opening of the gas nozzle 5. The gas nozzle 5
Is for discharging a desired shielding gas such as argon gas or carbon dioxide. The tips of the two wires 1a and 1b are arranged substantially parallel to each other at a small interval, and one of the consumable electrode wires 1a is located forward with respect to the welding progress direction (the direction of arrow A) and the other is filled with filler. Wire 1b
Is set to be located on the rear side. In addition to providing the filler wire 1b in a state parallel to the consumable electrode wire 1a, the filler wire 1b may be inclined with respect to the consumable electrode wire 1a within an angle range of, for example, about 20 °.

[0010] Of the two welding power sources 2a and 2b, one of the welding power sources 2a has its anode side connected to the chip 6a for the consumable electrode wire 1a via the wiring L1 and its cathode side connected to the motherboard via the wiring L2. The arc 8 is generated between the consumable electrode wire 1a, the base material 7, and the weld metal 9 by being connected to the material 7. On the other hand, the other welding power source 2b
Means that the cathode side is connected to the filler wire 1b via the wiring L3.
And the anode side is connected to the wiring L2 via the wiring L4. However, the wiring L2 is grounded, and the welding power supply 2b is configured to be able to supply the filler wire 1b with a current Ib opposite to the current Ia flowing through the consumable electrode wire 1a. As shown in FIG. 2, these two welding power sources 2a and 2b synchronize the two pulse currents Ia and Ib so that the phases are opposite to each other, and supply the pulse currents. It is configured. That is, when Ia (max), Ib (min)
However, when Ia (min), Ib (max) flows (however, FIG. 2 shows the absolute value of the current value ignoring the polarity of the potential).

The current detector 11 is provided on the wiring L3 so as to detect the value of the current Ib flowing through the filler wire 1b, and a comparator 13 is connected to the current detector 11. The comparator 13 compares the current Ib detected by the current detector 11 with the current Ic from the power supply 14 whose current value can be arbitrarily increased or decreased.
When the current Ib becomes larger than the value of the current Ic,
A signal for setting the timer circuit 12 is output so that the timer circuit 12 starts the time measurement. When the current Ib becomes smaller than the current Ic after such a state, the timer circuit 12 cancels the time measurement. A signal for resetting the timer circuit 12 is output. The timer circuit 12 starts time measurement by receiving a predetermined signal from the comparator 13 as described above. When the measured time reaches a predetermined time set in advance, the timer circuit 12 supplies the welding power sources 2a and 2b at that time. On the other hand, it is configured to transmit a control signal for stopping supply of the welding current. The timer circuit 12 is provided with a setting switch (not shown) capable of increasing and decreasing the timer setting time.

Next, an example of use and operation of the consumable electrode type arc welding machine will be described. First, the consumable electrode wire 1a is used as a leading wire, the filler wire 1b is used as a following wire, and a welding power source 2a is connected to each of these wires 1a and 1b.
2b, a predetermined pulse current is supplied, and an arc 8 is generated between one of the consumable electrode wires 1a and the base metal 7 and the weld metal 9.
Generate. In addition, the molten pool 10 generated by this arc 8
, The leading end of the subsequent filler wire 1b is inserted.
At this time, since the current Ib is also actively supplied from the welding power source 2b to the filler wire 1b, the filler wire 1b is heated by the resistance heat, and the melting speed is further increased. Therefore, even when welding a material having a high melting point such as iron or stainless steel, high-speed arc welding can be performed by promoting the melting of the filler wire 1b.

The directions of the currents Ia and Ib flowing through the wires 1a and 1b are opposite to each other, and the magnetic fields generated around the wires 1a and 1b by the currents Ia and Ib repel each other. Arc 8
Are prevented from melting and scattering the filler wire 1b biased toward the filler wire 1b behind. In this embodiment, the pulse current Ib is positively supplied to the filler wire 1b, but the pulse currents Ia and Ib flowing through the wires 1a and 1b have opposite phases as shown in FIG. In a relationship, both of the wires 1a, 1b,
When Ia (max) or Ib (max) flows through one of the wires and a large magnetic field is generated, Ib (min) or Ia (min) flows through the other wire and a weak magnetic force is generated. Since only a magnetic field is generated, both wires 1a, 1b
The repulsive force of the magnetic field does not fluctuate greatly, and a stable constant state is obtained. Therefore, the arc 8 is not excessively pushed forward due to the influence of the magnetic field.

As described above, the arc 8 can be positioned at a predetermined position by utilizing the repulsive force of the magnetic field. However, the two wires 1a and 1b drawn out from the wire reels 3a and 3b are , Because there are winding habits,
For these reasons, the ends of both wires 1a and 1b may come into contact with each other. When such a contact occurs, not only the value of the current Ia of the consumable electrode wire 1a but also the value of the current Ib flowing through the other filler wire 1b become very large. For example, as shown in FIG. The current Ic of the power supply 14 may exceed the set value. Then, when this is detected by the comparator 13, the timer circuit 12 is set, and the timer circuit 12 starts measuring the time during which the current Ib exceeds the current Ic.

The contact time between the consumable electrode wire 1a and the filler wire 1b is only instantaneous, and the time Ta during which the current Ib exceeds the value of the current Ic as shown by the arrow C in FIG. The time T preset in the timer circuit 12
If it is less than 1, the welding power sources 2a and 2b are not turned off and the current is continuously supplied to the wires 1a and 1b. Therefore, it is not necessary to interrupt the welding operation every time a large current that does not harm the welding power supplies 2a and 2b is generated instantaneously. In this case, the timer circuit 12 is reset when the current Ib returns to a normal value equal to or lower than the current Ic, so that no trouble occurs in the subsequent time measurement.

On the other hand, if the contact between the wires 1a and 1b is not immediately released, the time Tb during which the current Ib exceeds the current Ic is set in the timer circuit 12 in advance, as shown by the arrow D in FIG. In this case, when the timer circuit 12 measures the time T, a control signal for turning off the current supply is sent to both of the welding power sources 2a and 2b. Therefore, the welding power sources 2a and 2b receiving the control signal are immediately turned off, and the values of the currents Ia and Ib flowing through the wires 1a and 1b become zero.
Therefore, seizure does not occur in the welding power sources 2a and 2b.

In the above embodiment, the filler wire 1b
We have described a case where a welding power source 2b for generating high-temperature resistance heat is separately provided and configured as a welding machine suitable for welding high melting point materials such as iron and stainless steel, but the present invention is not limited to this. Not done. FIG. 4 shows another embodiment of the present invention in which only one welding power source 2a is used, in which a part of the current flowing from the consumable electrode wire 1a to the base material 7 is diverted to the filler wire 1b. It is. Even in the configuration shown in FIG. 7, the consumable electrode wire 1a and the filler wire 1b are provided in the same manner as in the embodiment shown in FIG.
When an excessive current is generated due to contact with, for example, the excessive current is detected by the comparator 13 via the current detector 11, the time when the excessive current is generated is started to be measured by the timer circuit 12, and the measured time is set to a predetermined value. When the predetermined time is reached, the welding power source 2a is turned off, and the welding power source 2a is protected. This configuration is suitable for a case where a sufficient melting rate is obtained only by inserting the filler wire 1b into the molten pool 10 and a low melting point base material such as an aluminum alloy which does not need to generate high-temperature resistance heat is arc-welded. It is. As described above, in the present invention, any of the types shown in FIGS. 1 and 4 may be used, and specific materials such as the base metal 7 to be welded are not specified.

In the present invention, the comparator 13 and the timer circuit 12 do not necessarily need to be used as the power control means, and the welding power may be turned off by other means. Similarly, the specific configuration of the current detecting means according to the present invention is not limited. In addition, in the present invention, the specific waveform of the current supplied to each wire does not matter, and the specific current value and the set time value which are the criteria for determining whether to turn off the welding power source. Is not specified.

[0019]

As will be understood from the above description, according to the consumable electrode type arc welding machine according to the present invention, both the consumable electrode wire and the filler wire come into contact during the arc welding operation, so that both wires are contacted. Even if a situation in which an excessive current flows unexpectedly occurs, the welding power can be turned off at a desired initial stage by accurately detecting this, so that the welding power may fail due to the excessive current. An extraordinary effect of improving safety without causing any serious inconvenience is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a consumable electrode type arc welding machine according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a current waveform supplied to each of a consumable electrode wire and a filler wire.

FIG. 3 is an explanatory diagram showing the operation of each part, a signal output state, and the like until the welding power source is turned off due to generation of an excessive current.

FIG. 4 is an explanatory view showing another embodiment of the consumable electrode type arc welding machine according to the present invention.

FIG. 5 is an explanatory view showing an example of a conventional consumable electrode type arc welding machine.

[Explanation of symbols]

 1a Consumable electrode wire 1b Filler wire 2a, 2b Welding power supply 5 Gas nozzle 7 Base material 8 Arc 9 Weld metal 10 Weld pool 11 Current detector 12 Timer circuit 13 Comparator 14 Variable power supply

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-16680 (JP, A) JP-A-58-1119464 (JP, A) JP-A-5-253671 (JP, A)

Claims (2)

(57) [Scope of request for utility model registration] 1. A consumable electrode wire and a filler wire for insertion into a molten pool are juxtaposed to each other, and a current supplied from a welding power source is applied to both the consumable electrode wire and the filler wire in opposite directions. A consumable electrode type arc welding machine configured to flow into the filler wire, wherein current detecting means for detecting a current value flowing through the filler wire, and a current value detected by the current detecting means is preset. Power supply control means for turning off the welding power supply when a predetermined current value is exceeded and the excess time has reached a predetermined time, a consumable electrode type arc welding machine. A power supply control means for detecting that the current detected by the current detection means has exceeded a predetermined current value and outputting a predetermined signal; and a predetermined signal from the comparator. 2. The consumable electrode type arc welding machine according to claim 1, further comprising: a timer for outputting a signal for turning off a welding power source when a signal output time reaches a predetermined time.