JPH0360865A - Wire strainer - Google Patents

Abstract

PURPOSE:To prevent the application of a large load on a feed motor for wire feeding so as to optimize wire feeding and to stabilize an arc by softening the wire by an electric heating system. CONSTITUTION:A shielding gas is previously injected into a sleeve 14 for gas shielding by utilizing a shielding gas terminal 13 and a short circuiting current is passed between upper and lower feed terminals 18a, 18b by a power source 20 for wire heating via secondary side connections 21a, 21b. The wire 3 positioned between feed contact chips 17 of the upper and lower feed terminals 18a, 18b is put into an energized state, by which electricity is generated and the wire is heated to soften. The bending of the wire 3 can be easily corrected to a straight shape when the feed motor 4 is driven. The feed speed of the wire 4 is measured by a wire feed speedometer 24 and the temp. of the wire 3 is measured by a wire surface temp. measuring instrument 25. The short circuiting current between the upper and lower feed terminals 18a, 18b is controlled by a temp. controller 26 in accordance with these measured values and the heating temp. of the wire 3 is so controlled as to be kept within a correct region.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wire strainer for use by being incorporated into an automatic welding device that performs welding work while feeding wire.

[Prior Art] In automatic welding equipment that performs welding work while feeding wire, especially automatic welding equipment that feeds wire at high speed, wire feeding performance has an important effect on stabilizing the arc. give. The above wire is usually wound into a coil, hard and permanently deformed, and cannot be used as it is because it causes problems such as fluctuations in the arc generation point during welding, so it is recommended to feed it in a straight shape. However, in order to stabilize the arc by keeping the arc length constant, it is necessary to feed the wire smoothly. In order to provide
It is necessary to correct the bend in the wire before feeding it.

The wire is fed by driving a feed motor, but the main role of the feed motor is to feed the wire so that the arc length is constant, and the feed motor does not straighten the wire before feeding. Doing so would add an extra load, which would affect the wire feedability and make the arc unstable. To this end, there is a need for a straightening mechanism for straightening wire bending that has a structure that applies only a light load that has little effect on arc length control. As a conventional wire straightening device, a wire strainer-a as shown in FIG. 4 is mainly used.

The above conventional wire strainer has two fixed rollers b.
A three-point roller pressure system in which one slide roller C and one slide roller C are arranged alternately is common, and the wire e pulled out from the wire spool d in the wire holder is passed through the conduit tube f and pasted by the above-mentioned fixed rollers, and the wire is slid The wire e, which has been straightened into a straight line, is pressed and straightened by passing it sequentially between rollers C1 and fixed rollers b, and the contact tip of the torch h is driven by a feed motor Q according to the arc length. It is set so that it is sent out from 1.

[Problems to be Solved by the Invention] However, in the case of the above-mentioned conventional wire strainer-a, when performing welding work while feeding the straightened wire e by the feed motor q, the pressing force is generated between the rollers b and c. Since the wire e that is currently attached is pulled out by the feed motor 0, there is a problem in that a large load is placed on the feed motor q. On the other hand, since the drive of the feed motor Q is controlled so that the wire e is fed according to the arc length, a large load acts on the feed motor Q as described above and the wire e is not fed. If not done properly, the arc length changes and the current changes, so
The feed of wire e will also be changed.

Incidentally, if the wire strainer a is not used, the above-mentioned problem will not occur, but it is impossible to straighten and feed the hard wire e that has been permanently deformed into a coil shape using only the feed motor 9. This is not possible due to the problems mentioned above.

SUMMARY OF THE INVENTION Accordingly, the present invention aims to make it possible to straighten the bend of a wire in a state where no load is applied to the feed motor when the wire is drawn out.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention has a method of straightening the bends of the wire when feeding the wire wound into a coil to the welding parts 1 to 1 by a feed motor. In the wire strainer to be straightened, an upper power supply terminal and a lower power supply terminal are arranged upstream of the feed motor at an appropriate interval, and the upper and lower power supply terminals are provided with:
The structure includes a power supply contact tip through which the wire is slidably inserted.

[Operation] When a short circuit current is passed between the upper and lower power supply terminals, the wire located between the power supply contact tip of the upper power supply terminal and the power supply contact tip of the lower power supply terminal is heated and softened, so that the feed motor The bending of the wire can be easily straightened by the pulling force.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which two wire spools 1 are rotatably supported by wire holders 2 attached to the main body of an automatic welding device (not shown), and coils are attached to each wire spool 1. After unwinding the wire 3 wound in a shape to straighten the bend, the feed motor 4
is fed to the torch 5 by driving the contact tip 5a.
An example of application to an automatic welding apparatus is shown in which the welding material 6 is welded by feeding the welding material 6 from the welding material 6 toward the material 6 to be welded. Note that 7 is an AC arc welding power source (capacity: 1500 to 1800 A), which connects a secondary connection 8a to the feed motor 4, a secondary connection 8b to the torch 5 via the power supply terminal 9, and , the secondary side connections 8c are connected to the ground terminals 10, 8 and 6, respectively, and the secondary side connections 8a are connected to each other to control the feeding speed of the wire 3 according to the ground current situation. It is equipped with a current control device 11 so as to be able to do so.

In the above configuration, a wire strainer is provided upstream of the feed motor 4 for straightening the bends of the wires 3 unwound from each wire spool 1 by electric heating.
12 will be provided. The wire strainer 12 has the following construction.

That is, a shielding gas sleeve 14 having an appropriate length extending in the vertical direction and having a shielding gas terminal 13 at the upper end is arranged above the torch 5, and the shielding gas sleeve 14 is attached to the automatic welding apparatus main body (not shown). An insulated gas terminal holder 1 holds the shield gas terminal 13 on a support column 15 that is supported so as to be able to rise and fall freely.
Attach via 6. Further, an upper power supply terminal 18a and a lower power supply terminal 18b each having two contact tips 17 for power supply, through which the wire 3 is freely inserted, are arranged at positions sandwiching the gas shielding sleeve 14 above and below. Then, each power supply terminal 18a, t
ab to the support column 15 using a power supply terminal holder 19, and the upper power supply terminal 18.
A and the lower power supply terminal 18b are connected to a wire heating power source (
Capacity: 500A > Secondary side connections 21a and 2 from 20
1b, and two wire guides 22 are placed above the upper power supply terminal 18a and below the lower power supply terminal 18b, and the upper wire guide 22 is connected to the upper support metal fitting 23a. Further, the lower wire guide 22 is supported by the lower support hardware 23b at the upper and lower ends of the pillar 15, respectively, and each wire spool 1
The two wires 3 unwound from the wire are supported by the upper support hardware 23a, respectively, the power supply contact tips 17 of the upper power supply terminal 18a, the gas shielding sleeve 14, and the power supply of the lower power supply terminal 18b. The contact tip 11 of the torch 5, each wire guide 22 supported by the lower support metal fitting 23b, and the wire feed section 4a1 by the feed motor 4 are passed through the torch 5 in order so as to protrude by a required amount from the contact tip 5a of the torch 5. The above-mentioned upper and lower power supply terminals 18a are in a state where the tip of the wire 3 is projected from the upper and lower power supply terminals 5a.

By applying electricity between the wires 18b, the wire 3 located inside the gas shielding sleeve 14 is heated (generated heat) and softened, thereby allowing the wire 3 to be straightened. In addition, in order to detect the feeding speed of the wire 3, secondary connections 21a, 21 from the wire heating power source 20 are connected.
A wire feed speed meter (tachometer) 24 connected to the upper power supply terminal 18a is installed at a position upstream of the upper power supply terminal 18a and supported by the support 15, and in order to measure the heating temperature of the wire 3, A wire surface temperature measuring device 25 connected to the next-side connections 21a and 21b is provided downstream of the lower power supply terminal 18b and supported by the support 15, and the wire feeding speed meter 24 and the wire surface temperature measuring device The configuration includes a temperature control device 26 for controlling the heating temperature of the wire 3 based on the measurement signal 25.

When welding the workpiece 6 using an automatic welding device equipped with the wire strainer 12 of the present invention, each wire 3 unwound from each wire spool 1 as shown in FIG.
The wire guide 22 is supported by the upper support hardware 23a.
, the power supply contact tip 17 of the upper power supply terminal 18a, the gas shield sleeve 14, the power supply contact chip 17 of the lower power supply terminal 18b, the wire guide 22 supported by the lower support hardware 23b, and the wire feed section 4a by the feed motor 4. After passing the wire one after another so that it protrudes a required amount from the contact tip 5a of the torch 5, the feed motor 4 is driven to feed the wire 3 while moving the torch 5 to perform welding work. At this time, shielding gas is injected into the gas shielding sleeve 14 using the shielding gas terminal 13, and a wire heating wire is connected between the upper and lower power supply terminals 18a and 18b via the secondary connections 21a and 21b. A short circuit current is caused to flow by the power supply 20. When a short circuit current is passed between the upper and lower power supply terminals 18a and 18b, the wire 3 located between the power supply contact tips 17 of the upper and lower power supply terminals 18a and 18b is energized, so that the wire 3 in this portion It will generate heat and become heated. Even if the wire 3 is made of mild steel, it is usually
In the heating range of 200 to 300°C, the strength does not change, but when the temperature reaches 350°C or higher, it begins to soften. Therefore, when the wire 3 is heated to a state where it is softened and not melted, for example, at about 420 to 500°C, and the feed motor 4 is driven, the bending of the wire 3 can be easily straightened by the pulling force acting on the wire 3. It can be corrected. In this case, even if a metallurgical defect or plastic deformation occurs in the wire 3 by heating the wire 3, there will be no problem since it will melt during welding.

In the above, the feeding speed of the wire 3 is measured by the wire feeding speed meter 24 upstream of the upper power feeding terminal 18a, and the temperature of the wire 3 is measured by the wire surface temperature measuring device 25 downstream of the lower feeding terminal 18b. The upper and lower power supply terminals 18a are determined based on these measured values.

By controlling the short circuit current between the wires 18b by the temperature control device 26, the heating temperature of the wire 3 is controlled to always be within the appropriate range. In addition, at this time, the wire 3 located between the upper and lower power supply terminals 18a and 18b is heated within the shield gas sleeve 14 in which shield gas (for example, argon, etc.) is injected, so that oxidation etc. can be prevented and straightening can be performed. Work can be done safely.

In this way, in the present invention, since the wire 3 is softened by the electric heating method, the bend in the wire 3 can be corrected with a small force, so that a large load is not applied to the feed motor 4. Therefore, the wire 3 can be fed properly according to the arc length.
It becomes possible to perform welding work stably with high precision. That is, since the feeding resistance of the wire 3 during straightening becomes extremely small, the arc can be stabilized.

In the above embodiment, the lower power supply terminal 18b is connected to the wire heating power source 20 using the secondary side connection 21b, but for example, as shown by the two-dot chain line in FIG. In addition, although the example shows the case where two wires 3 are heated at the same time, a single wire method may also be used. Of course, various changes can be made within the scope of the invention.

[Effects of the Invention] As described above, according to the wire strainer of the present invention, the wire can be softened by electric heating, so that the wire can be straightened by simply applying a small tensile force to the wire. Therefore, it is possible to avoid applying a large load to the feed motor for feeding the wire, and as a result, the wire can be fed properly and the arc can be prevented. It exhibits an excellent effect of being able to stabilize.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing one embodiment of the wire strainer of the present invention, Fig. 2 is a view taken from the ■-■ arrow in Fig. 1, and Fig. 3 is a
The plan view of the figure, FIG. 4, is a schematic diagram of a conventional wire strainer. DESCRIPTION OF SYMBOLS 1... Wire spool, 3... Wire, 4... Feed motor, 5... Welding torch, 12... Wire strainer-111... Contact tip for power supply, 1
8a... Upper power supply terminal, 18b... Lower power supply terminal.

Claims (1)

[Claims] (1) In a wire strainer that straightens the bends in a coiled wire when it is fed to a welding torch by a feed motor, an upper power supply is provided at an appropriate interval upstream of the feed motor. A wire strainer characterized in that a terminal and a lower power feeding terminal are arranged, and a power feeding contact tip is provided for slidably inserting the wire into each of the upper and lower power feeding terminals.