JP2009039742A - Arc welding equipment - Google Patents

Abstract

An arc welding apparatus that improves the feedability of a welding wire and is easy to adjust the length of a spring liner.
In an arc welding apparatus in which a welding wire is fed to a welding torch 2 at the tip of a robot and an electric current is passed through the welding torch 2, the welding torch 2 inserts a welding liner 10 containing the welding wire. A collet adapter 12 attached to the tip of the torch body 11, a chip adapter 15 attached to the tip of the collet adapter 12, a contact tip 16 attached to the tip of the chip adapter 15, and the torch body penetrating through the collet adapter 12. The nozzle 13 is attached to the insulator 13 and covers the chip adapter 15 and the contact chip 16. The tip of the collet adapter 12 is provided with a tapered portion and a slit.
[Selection] Figure 2

Description

  The present invention relates to an arc welding apparatus, and more particularly to an arc welding apparatus that performs welding by a robot having a welding torch attached to the tip.

In recent years, welding apparatuses using industrial robots have been widely used. In general, a robot having a plurality of joint axes includes a welding torch at the wrist tip, and performs a welding operation while moving the welding torch along a desired welding line.
FIG. 7 is a schematic diagram showing the overall configuration of a conventional arc welding apparatus.
In FIG. 7, reference numeral 71 denotes a robot having a plurality of joint axes, and a welding torch 72 is attached to the tip. The robot 71 is operated by a servo motor (not shown) provided on each joint axis, and each axis servo motor is feedback-controlled by a robot control device 77 connected to the robot 71. 78 is a teaching device for teaching the robot 71 and performing various operations. A welding power source 79 supplies a current for arc welding to the welding torch 72 in accordance with a command from the robot controller 77.
The robot 71 includes a welding wire feeder 76 on the arm, and the welding wire feeder 76 inserts a conduit cable into the welding torch 72. The conduit cable includes a welding liner (spring liner), and the welding liner has a welding wire 73 inserted therein. The welding wire 73 supplied to the welding wire feeder 76 is stored in a welding wire can 74, and gas is further supplied to the welding wire feeder 76 from a gas cylinder 75. The welding liner is used for the purpose of protecting and guiding the welding wire 73 from buckling.

FIG. 8 shows a side view of the tip of a conventional welding torch. In order to show the internal structure, a partial half sectional view is shown. FIG. 9 is an exploded view showing in detail the mechanism of the welding torch tip of FIG. In FIGS. 8 and 9, the welding torch is shown in a state where the welding torch is tilted sideways from the state of the welding torch 72 in FIG.
The welding torch 72 has a hollow structure for inserting a conduit cable, and a contact tip 16 is attached to the tip of the welding torch 72, and a current for arc welding is supplied to the contact tip 16 from a welding power source 79. . The welding liner 10 inserted into the welding torch 72 reaches partway in the welding torch 72, and only the welding wire 73 in the welding liner 10 passes through the contact tip 16 from the tip of the tip body 18.
An insulator 13 and an orifice 14 are attached between the tip of the tip body 18 and the contact tip 16 so as to cover the tip body 18. The insulator 13 is attached to the tip of the torch body 11, and the nozzle 17 is attached to the insulator 13. The orifice 14 is made of an insulator such as ceramic and has a plurality of gas holes. The gas holes are also provided in the tip body 18 so that when the welding torch 72 is assembled, the positions of the gas holes in the longitudinal direction of the welding torch coincide with each other.
The orifice 14 is used to make it difficult for electrical conduction between the insulator 13 and the nozzle 17 due to the spatter scattered in the nozzle 17 during arc welding. However, the orifice 14 can be omitted by covering the inner surface of the nozzle 17 with an insulator.

The gas supplied from the gas cylinder 75 (FIG. 7) to the welding wire feeder 76 (FIG. 7) passes through the conduit cable and further passes through the gas holes provided in the tip body 18 and the orifice 14 via the torch body 11. And ejected from a nozzle 17 covering the contact chip 16. This gas becomes a shielding gas that shields arc discharge during welding from the atmosphere. That is, in the arc welding apparatus of FIG. 7, gas shield arc welding is performed.
The general structure of the gas shielded arc welding torch is disclosed in, for example, Patent Document 1 and Patent Document 2 in addition to FIGS. 8 and 9.
Utility Model Registration No. 3105620 JP 2003-251466 A

However, the invention described in Patent Document 1 is not satisfactory in that high-quality welding preferable in terms of arc welding quality is performed.
Experiments by the present applicant have found that the feedability of the welding wire has a great influence on the quality of arc welding. In particular, even if the welding wire feeding device feeds the welding wire evenly, there is a slack or play of the welding wire between the welding wire feeding device and the contact tip in the welding torch, so that a uniform wire can be obtained. In some cases, the delivery was hindered.
In the invention described in Patent Document 1, a spring liner is used for protecting the welding wire, but the spring liner is not fixed in the welding torch and has no effect of suppressing play in the feeding direction of the welding wire. It has been found that such fluctuations in the welding wire feed amount have an adverse effect on arc welding quality.
In addition to the play of the welding wire, plating on the surface of the welding wire or dust adhering to the surface layer clogs the welding torch, which causes a deterioration in the feedability of the welding wire. Therefore, it was necessary to periodically remove the welding wire from the welding torch and clean the inside of the welding torch. In the case of an arc welding apparatus such as Patent Document 1, cleaning is performed by pulling out the spring liner from the welding wire feeding apparatus side (the rear side of the welding torch).
In this respect, since the guide ring and the flexible tube are applied in Patent Document 2, there is an advantage that there is no play of the welding wire, but it is difficult to remove the flexible tube, so it is difficult to clean the inside of the welding torch. .
In addition, this structure is more expensive than a method using a spring liner.

In general, in an arc welding apparatus, it is necessary to appropriately adjust the length of the welding liner 10 (FIG. 8) prior to welding. Since the welding liner 10 covers and protects the welding wire 73 for the purpose of preventing the buckling of the welding wire 73, it exists as close as possible to the rear end of the contact tip 16 in the welding torch 72. Is desirable.
In the adjustment, first, as shown in FIG. 9, the nozzle 17, the contact tip 16, the orifice 14, and the insulator 13 are removed from the front end portion of the welding torch 72, and the welding liner 10 is started from the rear end portion of the welding torch 72. Measure how much is protruding. Then, the welding liner 10 is pulled out from the rear end portion of the welding torch 72, and the tip of the welding liner 10 is cut by the amount of protrusion measured earlier. Again, the welding liner 10 is inserted from the rear end of the welding torch 72 so that the tip of the welding liner 10 and the tip of the tip body 18 are aligned.
However, in the conventional welding torch 72 as shown in FIGS. 8 and 9, it is difficult to understand the length to cut the welding liner 72, and trial and error are repeated, which takes time and effort for prior adjustment.
Furthermore, if the length of the welding liner 10 is adjusted to be short, the welding wire 73 (FIG. 7) is not protected by the welding liner 10 before the contact tip 16, and buckles and feedability deteriorates. was there.

  In addition to the feedability of the welding wire 73, there is a shielding gas as a factor affecting the quality of arc welding. As described above, the shielding gas is supplied into the welding torch 72 together with the welding wire 73. In a structure using a general spring liner, the spring liner may be eccentric inside the welding torch 72 and block the gas hole in the welding torch 72. When the gas hole is blocked, the shield gas supply from the nozzle is stagnated or biased, which causes poor welding.

  The present invention has been made in view of such problems, and while applying an inexpensive spring liner to protect the welding wire, the play of the welding wire is eliminated and the feedability is improved, and the length of the spring liner is increased. An object of the present invention is to provide an arc welding apparatus capable of ensuring ease of adjustment and maintenance of a welding torch, and further preventing arc gas plugging by a spring liner to improve arc welding quality.

In order to solve the above problem, the present invention is configured as follows.
An invention according to claim 1 relates to an arc welding apparatus, comprising a welding torch attached to a tip of a robot's hand, feeding a welding wire to the welding torch and causing an electric current to flow through the welding torch. In the arc welding apparatus for performing welding, the welding torch inserts a liner containing the welding wire, a collet adapter attached to the tip of the torch body, and a tip adapter attached to the tip of the collet adapter ,
A contact tip attached to the tip of the tip adapter, an insulator penetrating the collet adapter and attached to the torch body,
The nozzle is attached to the insulator and covers the tip adapter and the contact tip, and the collet adapter has a tapered shape and a slit.
According to a second aspect of the present invention, in the front of the arc welding apparatus according to the first aspect, the collet adapter includes at least four of the slits at a tip portion and a circular hole at a rear end portion of each of the slits. It is characterized by that.
The invention according to claim 3 is the arc welding apparatus according to claim 1 or 2, wherein the tip adapter is attached to the collet adapter so as to cover a tip of the collet adapter, and an inner surface of a joint portion with the collet adapter is provided. A taper portion that matches the taper shape at the tip of the collet adapter is provided.
According to a fourth aspect of the present invention, in the arc welding apparatus according to the first aspect, the welding torch penetrates the collet adapter together with the insulator and is fixed by being sandwiched between the insulator and the tip adapter, and is attached to the nozzle. And an inner diameter of a tip end of the orifice is smaller than an outer diameter of a rear end of the chip adapter.

According to the present invention, the spring liner rear end is fixed on the welding wire feeding device side, and the welding liner front end is fixed with the collet adapter and the tip adapter, so that there is no sagging or play of the welding wire, The feeding amount of the welding wire becomes uniform and the welding quality is improved.
Also, fixing the welding liner tip on the center line of the collet adapter eliminates the eccentricity of the welding liner inside the torch body tip, so the shield gas supplied to the welding torch is uniformly injected from the nozzle. And the welding quality is improved.
Further, the cleaning in the welding torch and the adjustment of the length of the welding liner before the start of welding can be performed easily and accurately. As a result, the feedability of the welding wire is ensured and the welding quality is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing the overall configuration of an arc welding apparatus according to the present invention.
In FIG. 1, reference numeral 1 denotes a robot having a plurality of joint axes, and a welding torch 2 is attached to the tip. The robot 1 is operated by a servo motor (not shown) provided on each joint axis, and each axis servo motor is feedback-controlled by a robot control device 7 connected to the robot 1. 8 is a teaching device for performing teaching and various operations of the robot 1. A welding power source 9 supplies a current for arc welding to the welding torch 2 in accordance with a command from the robot controller 7.
The robot 1 includes a welding wire feeding device 6 on the arm, and the welding wire feeding device 6 inserts a conduit cable into the welding torch 2. The conduit cable contains a welding liner (spring liner), and the welding liner has a welding wire 3 inserted therein. The welding wire 3 supplied to the welding wire feeding device 6 is stored in a welding wire can 4, and gas is further supplied to the welding wire feeding device 6 from a gas cylinder 5. The welding liner is used for the purpose of protecting and guiding the welding wire 3 from buckling.

FIG. 2 is a side view of the welding torch 2 attached to the tip of the robot 1 in the arc welding apparatus of the present invention, and is a partial half sectional view for showing the internal structure. FIG. 3 is an exploded view showing in detail the mechanism of the welding torch of FIG. 2 and 3 show the welding torch in a state where it is tilted sideways from the state shown in FIG.
The torch body 11 has a hollow structure similar to the conventional welding torch 72 (FIG. 8), and the welding liner 10 delivered from the welding wire feeder 6 (FIG. 1) passes through the torch body 11 and further torch. It passes through the collet adapter 12 attached to the tip of the body 11. The collet adapter 12 and the torch body 11 are coupled to each other by screw grooves provided on the outer surface of the rear end portion of the collet adapter 12 and the inner surface of the tip end of the torch body 11. That is, the collet adapter 12 can be detached from the torch body 11.
The outer periphery of the collet adapter 12 is covered with an insulator 13 and an orifice 14. The insulator 13 and the torch body 11 are coupled to each other by screw grooves provided on the inner surface of the rear end portion of the insulator 13 and the outer surface of the tip end of the torch body 11. The collet adapter 12 is also provided with the same gas hole 12e (FIG. 4) as the tip body 18 of FIG. 8, and when the welding torch 2 is assembled, the welding torch longitudinal direction of the gas hole 12e of the collet adapter 12 and the orifice 14 is provided. The positions of are matched. However, as described in the background art, the orifice 14 can be omitted by covering the inner surface of the nozzle 17 with an insulator.
A tip adapter 15 is attached to the tip of the collet adapter 12, and a contact tip 16 is further attached to the tip of the tip adapter 15. The collet adapter 12 and the chip adapter 15 and the chip adapter 15 and the contact chip 16 are also coupled by screw grooves.
The welding liner (spring liner) 10 is cut to have a length adjusted so as to reach the tip position of the collet adapter 12, and only the welding wire 3 extends from the tip of the collet adapter 12 to the tip adapter 15 and the contact tip 16. It goes out of the tip of the contact chip 16 through the inside. Adjustment of the length of the welding liner 10 will be described later.

  As apparent from comparison between FIGS. 2 and 3 and FIGS. 8 and 9, in the welding torch 2 according to the present invention, the collet adapter 12 is used in place of the tip body 18 used in the conventional welding torch 72. Further, it is characterized in that a tip adapter 15 that is not included in the conventional welding torch 72 is newly provided.

FIG. 4 shows the collet adapter 12. (A) is side sectional drawing, (b) is the front view seen from the arrow direction of (a). As shown in FIG. 4, the collet adapter 12 is provided with four slots 12a at the tip, and has a circular hole 12b at the rear end of each slot 12a.
The four slits 12a are arranged so as to form 90 ° with each other when viewed from the front. Further, the tip of the collet adapter 12 has a tapered shape 12c, and a male screw portion 12d is provided behind the tapered portion 12c. A gas hole 12 e is provided at the central portion in the length direction of the collet adapter 12.

FIG. 5 shows the chip adapter 15. (A) is side sectional drawing, (b) is the front view seen from the arrow direction of (a). As shown in FIG. 5, the chip adapter 15 is provided with a tapered portion 15c on the inner surface, and female screw portions 15d and 15e are provided on the inner surfaces of both ends.
The taper portion 15 c on the inner surface of the chip adapter 15 is shaped to match the taper 12 c at the tip of the collet adapter 12, and the female screw portion 15 e at the rear end of the chip adapter 15 is also compatible with the male screw portion 12 d of the collet adapter 12. It is like that.
Further, the taper portion 15c is provided so that the smallest inner diameter is slightly larger than the outer diameter of the welding liner 10 (FIG. 2).
Further, the female screw portion 15 d on the inner surface of the tip end of the chip adapter 15 is adapted to be fitted with a male screw provided at the rear end portion of the contact chip 16.

The length adjustment of the welding liner before performing the welding operation in the arc welding apparatus of the present invention using the welding torch having the above structure will be described with reference to FIG. As described above, prior to the arc welding operation, it is necessary to adjust the length of the welding liner 10 and cut the tip at an appropriate location. The rear end of the welding liner 10 inserted into the welding torch 2 from the wire feeder 6 (FIG. 1) is fixed by the wire feeder 6.
First, as shown in FIG. 3, the nozzle 17, the contact tip 16, the tip adapter 15, the orifice 14, and the insulator 13 are removed from the tip of the welding torch 2 to expose the collet adapter 12.
As shown in FIG. 6A, the welding liner 10 adjusted to a rough length is inserted in the direction of the arrow from the rear side of the collet adapter 12 of the welding torch 2.
Subsequently, as shown in FIG. 6B, after the welding liner 10 protruding from the tip of the collet adapter 12 is aligned with the tip 12t of the collet adapter 12 and cut (dotted line portion), the insulator 13 and the orifice 14 are again colleted. Cover the adapter 12 (note that the insulator 13 and the orifice 14 are not shown in the figure), and the tip adapter 15 is attached to the tip of the collet adapter as shown in FIG.
As described above, the inner surface of the rear end of the chip adapter 15 is provided with a taper that matches the tip of the collet adapter 12. Since the tip of the collet adapter 12 is divided by slitting, when the chip adapter 15 is screwed to the tip of the collet adapter 12, the tip of the collet adapter 12 is tightened by the taper of the inner surface of the chip adapter 15. As a result, it contacts the welding liner 10 inside the tip of the collet adapter 12. As a result, the welding liner 10 inside the tip of the collet adapter 12 is fixed.
This is shown in FIG. 6 (d). FIG. 6E is a front view showing a state in which the tip tapered portion of the collet adapter 12 is tightened by the chip adapter 15 from the arrow direction toward the center of the collet adapter 12.
Further, the male screw at the rear end of the contact chip 16 is attached to the female screw at the tip of the chip adapter 15. By doing so, the rear end surface of the contact chip 16 comes into contact with the front end of the collet adapter 12.
Due to the above configuration, when adjusting the length of the welding liner 10, the welding liner 10 is cut in accordance with the end surface of the tip of the collet adapter 12, and the tip adapter 15 is connected to the tip of the collet adapter 12. The length of the welding liner can be adjusted simply by attaching it to. Finally, the nozzle 17 is attached to the insulator 13.

According to the present invention, when adjusting the length of the welding liner 10 as in the conventional welding torch, there is no need to pull out the welding liner 10 from the rear side of the welding torch 2, and the adjustment is completed in a short time and accurately. To do.
Further, when the chip adapter 15 is attached to the tip of the collet adapter 12 by screwing, as shown in FIG. 4B, the tip of the collet adapter 12 is provided with four slots at 90 ° intervals. The welding liner 10 in the tip of the collet adapter 12 is evenly tightened from the four directions. As a result, the welding liner 10 is fixed on the center line of the collet adapter 12.
The shield gas supplied from the gas cylinder 5 through the feeding device 6 is supplied to the tip of the welding torch in a state along the welding liner 10, and is provided in the gas hole 12 e and the orifice 14 provided in the collet adapter 12. It has a structure that jets out toward the nozzle 17 through the gas hole. As described above, the welding liner 10 is fixed on the center line without being decentered in the collet adapter 12, so that the gas hole is not blocked. Therefore, the shielding gas is uniformly injected from the nozzle 17 to reliably shield arc discharge during welding from the atmosphere, thereby contributing to improvement in welding quality.
Note that the slit of the tip of the collet adapter 12 is not limited to four, and for example, the tip of the collet adapter 12 may be divided into six at 60 ° intervals.
By the way, the outer diameter of the rear end of the chip adapter 15 is larger than the inner diameter of the tip of the orifice 14. Thus, the shield gas is reliably supplied from the gas hole to the nozzle 17 without leaking from the tip of the orifice at the joint portion between the tip adapter 15 and the orifice 14.

  When cleaning the inside of the welding liner 10 and the welding torch, the nozzle 17 and the contact tip 16 are first removed from the welding torch. If the tip adapter 15 is further loosened, the fixing of the welding liner 10 by the tapered portion at the tip of the collet adapter 12 is released, so that the welding liner 10 can be pulled out from the wire feeder 6 side. With the welding liner 10 pulled out, the welding torch can be reliably cleaned.

It is a mimetic diagram showing the whole arc welding device composition concerning the present invention. It is a side view of the welding torch used by the present invention. It is an exploded view of the welding torch used by this invention. It is a figure which shows the collet adapter of a welding torch, (a) is a sectional side view, (b) is the front view seen from the arrow direction of (a). It is a figure which shows the chip adapter of a welding torch, (a) is a sectional side view, (b) is the front view seen from the arrow direction of (a). It is a figure which shows the length adjustment method of a welding liner, (a) is sectional drawing explaining a mode that a welding liner is inserted from the rear side of a collet adapter, (b) is a welding liner which protruded from the front-end | tip of a collet adapter. (C) is a cross-sectional view for explaining how to attach the chip adapter to the tip of the collet adapter, (d) is a cross-sectional view for explaining how to fasten the chip adapter to the tip of the collet adapter, e) It is a front view explaining a mode that the taper part of the front-end | tip of a collet adapter is fastened with a chip adapter. It is a schematic diagram showing the whole structure of the conventional arc welding apparatus. It is a side view of the conventional welding torch. It is an exploded view of the conventional welding torch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot 2 Welding torch 3 Welding wire 4 Welding wire can 5 Gas cylinder 6 Welding wire feeding device 7 Robot control device 8 Teaching device 9 Welding power supply 10 Welding liner (spring liner)
11 Torch body 12 Collet adapter 12a Slot 12b Circular hole 12c Tapered portion 12d Male screw portion 12e Gas hole 12t Collet adapter tip 13 Insulator 14 Orifice 15 Tip adapter 15c Tapered portions 15d, 15e Female screw portion 16 Contact tip 17 Nozzle 18 Tip body

Claims (4)

In an arc welding apparatus comprising a welding torch attached to the tip of a hand of a robot, and performing arc welding by the welding torch by feeding a welding wire to the welding torch and passing an electric current through the welding torch.
The welding torch is
A torch body for inserting a liner containing the welding wire;
A collet adapter attached to the tip of the torch body;
A chip adapter attached to the tip of the collet adapter;
A contact chip attached to the tip of the chip adapter;
An insulator penetrating the collet adapter and attached to the torch body;
A nozzle attached to the insulator and covering the tip adapter and the contact tip,
An arc welding apparatus, wherein the collet adapter has a tapered tip and a slit.   2. The arc welding apparatus according to claim 1, wherein the collet adapter includes at least four of the slits at a front end portion and a circular hole at a rear end portion of each of the slits.   The chip adapter is attached to the collet adapter so as to cover a tip of the collet adapter, and has an inner surface of a coupling portion with the collet adapter, and a tapered portion that matches a tapered shape of the tip of the collet adapter. Item 3. An arc welding apparatus according to item 1 or 2.   The welding torch is penetrated by the collet adapter together with the insulator, and is fixed by being sandwiched between the insulator and the tip adapter, and includes an orifice covered with the nozzle. The inner diameter of the tip of the orifice is the tip adapter The arc welding apparatus according to claim 1, wherein the arc welding apparatus is smaller than the outer diameter of the rear end.

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