JPH0329511B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding wire feeding device for automatic and semi-automatic arc welding.

In general, CO ₂ welding, MAG welding, MIG welding, etc. that use continuous electrode wires, automatic and semi-automatic arc welding using consumable electrode methods, TIG welding, plasma welding, brazing, etc. that use additive wire, etc.
Needless to say, it is necessary to smoothly feed a continuous welding wire to the welding point and stably supply it to the arc portion.

In particular, there is a considerable distance between the wire reel containing the welding wire and the welding torch operated by the operator, and a flexible conduit cable is used to connect the two, so-called semi-automatic arcs. In welding, it is well-experienced that the wire feeder provided on the wire reel side and the wire feeding function of the wire guide section in the conduit cable have a significant effect on welding characteristics.

Therefore, in cases such as semi-automatic arc welding, where the length of the conduit cable must be set particularly long, or where the conduit cable must be extremely curved at the tip of the welding torch, Although various countermeasures have been considered for smooth and stable feeding, none of them have been able to provide sufficiently satisfactory performance.

On the other hand, in cases where the positions of the wire reel and welding torch are approximately fixed and the wire feeding path connecting them does not change much, for example in jig arc welding equipment or robot welding equipment, the feeding path If the wire is extremely curved and the radius of curvature of the curved part is small, the wire feeding will become unstable.Especially in robot welding equipment, it is difficult to prevent fluctuations in the feeding load by rotating the tip of the wrist. It is often unavoidable.

Therefore, when feeding the welding wire to a feeding path with such a curved part, the welding wire is rotated in the circumferential direction of the guide tube through which the welding wire is inserted to form the feeding path. One possible method is to actively reduce the feeding load by feeding .

By the way, when adopting such a means, if a constant curve is always formed in the feed path and the degree of curve hardly changes, the guide tube must be rotated at a constant speed during welding work. However, during actual welding work, especially when moving around the welding site by holding the welding torch by hand, such as in semi-automatic arc welding, the feed path may go from a nearly straight line to an extremely curved position. Under these circumstances, it would be uneconomical and uneconomical to always rotate the guide tube at a constant speed.

Furthermore, as mentioned above, in robot welding equipment, the degree of curvature of the feed path constantly changes due to the rotation of the wrist, so the same thing can be said here as in semi-automatic arc welding. It is.

The present invention has been made in view of the above circumstances, and its purpose is to provide a feed path with a curved portion in automatic or semi-automatic arc welding, and in particular, in a case where the degree of curvature constantly changes. It is an object of the present invention to provide a welding wire feeding device that can appropriately reduce the feeding load and feed the welding wire stably and smoothly without waste even in such cases.

In order to achieve the above object, the present invention is characterized by being configured as follows.

That is, a welding wire fed by a wire feeder is inserted into a guide tube whose inner circumferential wall has a spiral shape, and the guide tube is rotated in the circumferential direction, and the welding wire is fed. The feeding force is detected and the guide tube is rotated and stopped or the rotational speed is controlled based on the value corresponding to the feeding force, and the rotation of the guide tube directs the welding wire in the feeding direction. It receives a thrust force, uses this thrust to actively reduce the feed load, and also rotates the guide tube as needed and as much as necessary depending on the degree of curvature in the feed path to achieve the above effect. This allows stable and smooth feeding of welding wire without waste and effectively.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic diagram showing the operating principle of a welding wire feeding device based on the present invention, in which 1 is a wire reel around which a welding wire 2 is wound, and the welding wire is fed out from the wire reel 1. 2 is inserted into a conduit cable 4 constituting a wire feeding path while being pulled by a wire feeder 3, and is fed to a welding torch 5, generating an arc 7 between it and the workpiece 6. At least continuous welding work is performed.

The above-mentioned wire feeder 3 is a normal type that feeds the welding wire 2 in the direction of arrow α while being clamped by a feed roll 3a and a pressure roll 3b, and the drive shaft 3c of the feed roll 3a is decelerated. It is connected to the output shaft of a drive motor 3e via a mechanism 3d.

By the way, the above-mentioned conduit cable 4 has a jacket 8.
and a guide tube 9 which is rotatably housed in the inner circumferential portion of the outer sheath 8 over almost its entire length.In particular, the inner circumferential wall of the guide tube 9 through which the welding wire 2 is inserted has a spiral shape. form.
Note that the guide tube 9 in this embodiment uses a helical spring made of a thin metal wire wound in a spiral shape.

Then, an output shaft 10a of a guide tube drive motor 10 inserted between the wire feeder 3 and the base end of the conduit cable 4 is connected to one end of this guide tube 9 via a connector 11. 10, the guide tube 9 side through which the welding wire 2 is inserted is rotated at high speed in the circumferential direction thereof.

Note that the welding wire 2 is guided into the guide tube 9 by passing through the cylindrical output shaft 10a.

Reference numeral 12 in the figure is a feeding force detection means for detecting the feeding force for feeding the welding wire. The required feeding force for feeding the welding wire 2 is indirectly detected.

Then, a detection signal based on the value of the feeding force detected by the feeding force detection means 12 is sent to the control circuit 1.
I am trying to output to 3.

Based on the detection signal, this control circuit 13
The guide tube drive motor 10 is controlled to start when the feeding force, that is, the load current increases beyond a certain value, and the guide tube drive motor 10 is controlled to stop when the load current decreases below a certain value. This is what I did.

Next, the operation of the device based on this embodiment will be explained.

Now, if we start the wire feeder 3 and the guide tube drive motor 10 at the same time and feed the welding wire 2 into the conduit cable 4, the welding wire 2 will move in the spiral shape of the guide tube 9 rotating at high speed. A thrust is received from the inner circumferential wall in the direction of advancing the welding wire 2, and this thrust significantly reduces the feeding load that was generated by the feeding resistance inside the guide tube, so the feeding path is particularly curved. Even when the feeding load is large, the feeding load is reduced to a negligible level by the rotation of the guide tube 9, and the welding wire 2 is stably and smoothly fed to the welding torch 5. be able to.

Here, the correlation between the rotational speed N of the guide tube 9 and the wire feeding force, that is, the load current I of the wire feeder 3, is determined by making sure that the feeding path for feeding the welding wire 2 is straight as shown in FIG. Once or twice from a situation
When we investigated the cases where the state was changed to a state involving two loops and three loops, we obtained curves (1), (2), (3), and (4) as shown in Figure 3.

That is, curve (1) is for the case where the feed path is straight, and curves (2), (3), and (4) are for the case where the feed path involves one, two, and three loops, respectively. It is something.

Therefore, when the load current I detected by the feeding force detection means 12 becomes larger than Io, the control circuit 13 controls the guide tube drive motor 10.
If set to start, in the case of curve (3), that is, when there are two loops in the feeding path, the load current I will gradually decrease as the drive motor 10 rotates, and the guide tube 9 will start. The rotation speed of
When _N3 is reached, the load current I decreases to Io.

If the guide tube drive motor 10 continues to be energized, the rotational speed N of the guide tube 9 will increase from N ₃ and the load current I will further decrease, but the load current I will become (Io - △I). If the current is set to be cut off to the drive motor 10 at this point, the load current I will change slightly within the range from (Io - △I) to Io, that is, the feeding force will hardly change. The welding wire 2 can be fed by.

By the way, in actual welding work, the feed path is constantly changing, especially when the worker moves around the welding site while holding the welding torch by hand, as in semi-automatic arc welding. As shown in FIG. 2, for example, the feeding path constantly changes between (1) and (4).

Now, if the feed route changes from state (3) in the same figure,
If the state changes to state (4), the state changes from the state shown by curve (3) to the state shown by curve (4) in FIG.

Therefore, the load current I increases from Io to _I1 , and since the guide tube drive motor 10 is energized by the control circuit 13, the rotational speed N of the guide tube 9 increases from _N3 to _N4 , and the load current I is automatically controlled so that it falls within the range of (Io-ΔI) to Io again.

Therefore, even if the feeding path for feeding the welding wire constantly changes between (3) and (4) as shown in Figure 2, the feeding force will always be constant. , stable and smooth feeding can be effectively carried out without unnecessary rotation of the guide tube 9.

On the other hand, as shown in Figure 2, the feed path is straight.
In the case of (1) or the case of (2) with only one loop, even if the guide tube 9 is in a stopped state, the load current I Since is lower than Io, the guide tube drive motor 10 is not activated.

In other words, this means that when the feeding path is straight or curved with about one loop, there is no need to rotate the guide tube 9 to reduce the feeding force. In this case, the feed is carried out by a normal feeding method, that is, a method in which the guide tube 9 does not rotate.

Further, as soon as the feed path changes from the state (1) or (2) to the state (3) or (4) in FIG. 2, the guide tube drive motor 10 is started and the control as described above is performed. It is.

In the above embodiment, the wire feeding force is indirectly detected by the load current of the wire feeder 3, but the feeding force detecting means in the present invention is not limited to such a means. Needless to say.

Other means for detecting the wire feeding force include, for example, a tensile force between the wire feeder 3 shown in FIG. 1 and a base (not shown) on which the wire feeder 3 is disposed, or Pressure sensor (strain gauge, etc.)
may be inserted, and the feeding reaction force accompanying feeding of the welding wire 2 may be detected by the sensor.

In addition, the above-mentioned setting current Io needs to be set to a value that takes into account the diameter, material, etc. of the welding wire 2 and allows stable and smooth feeding without buckling the welding wire 2 during feeding. Needless to say, there is.

Further, in the above embodiment, when the load current I of the wire feeder 3 reaches a predetermined value, that is, Io and (Io - ΔI), the guide tube drive motor 10 is turned on.
Although off-control is performed, the control method is not limited to this, and the guide tube drive motor 10 may be feedback-controlled, for example, so that the load current I is always Io.

As described above, the present invention actively controls the required feeding force of the welding wire by inserting the welding wire into the guide tube whose inner peripheral wall is formed in a spiral shape and rotating the guide tube in the circumferential direction. In particular, the required feeding force is detected by a feeding force detection means, and the rotation and stop control or speed control of the guide tube is performed based on the detection result. Depending on the degree of curvature that occurs in the feeding path, the guide tube can be rotated as much as necessary to reduce the required feeding force, ensuring stable and smooth feeding of welding wire without waste. Therefore, it is possible to provide a welding wire feeding device that can perform welding.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG.
The figures are schematic diagrams showing examples of curved parts that occur in the feeding path,
FIG. 3 is a graph showing the relationship between the rotational speed of the guide tube and the load current of the wire feeder in the example. 2...Welding wire, 3...Wire feeder, 9...
...Guide tube, 10...Guide tube drive source, 12...Feeding force detection means, 13...Control circuit.

Claims (1)

[Scope of Claims] 1. A wire feeder that feeds a welding wire, a guide tube whose inner peripheral wall has a spiral shape, into which the welding wire fed by the wire feeder is inserted;
A guide tube drive source that rotates the guide tube in the circumferential direction, a feeding force detection means that detects the feeding force for feeding the welding wire, and a feeding force detecting means that detects the feeding force that feeds the welding wire. A welding wire feeding device comprising: a control circuit that performs on/off control or speed control of the guide tube drive source based on the value. 2. Claim 1, characterized in that the feeding force detection means detects the load current of the wire feeder, and changes in the feeding force are detected by changes in the load current. Welding wire feeding device as described in . 3. The welding wire feeding device according to claim 1, wherein the guide tube is formed of a helical spring made of a wire wound helically.