JP2002224837A - Arc welding torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torch for an arc welding, with which a sputter does not stick on a power feeding tip or the like, or the sputter is easily removable even if attached, and the flow of a shield gas in a nozzle is slightly disturbed. SOLUTION: The tip part of a torch tip member 22 is covered with a copper cap 34 so that the power feeding tips 26a and 26b and leaf springs 27a and 27b are enclosed, a ceramic guide cylinder 35 on which a insertion hole 37 is made of which the cross-sectional form is a equilateral triangle, of which the inscribed circle has a diameter larger than the diameter of the power feeding wire 3 by 0.03 to 0.05 mm, is fitted at the central part of the tip of the cap 34, the shield gas, which is ejected into the cap 34 through a central hole 23 which penetrates the axis part of the torch tip member 22, impinges upon the power supply tips 26a and 26b, cools them, and further cools the cap 34 in the course in which the gas reverses its course at the bottom part of the cap 34 and ascends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive torch tip member for guiding a shielding gas through a central hole through which a current-carrying wire for consumable electrode arc welding is inserted, and a rear end portion rotatably supported. The present invention relates to an arc welding torch including a current-carrying tip that is biased in a direction in which a tip portion contacts a current-carrying wire.

[0002]

2. Description of the Related Art In most cases, a wire used in conventional consumable electrode arc (hereinafter abbreviated as GMA) welding has a circular cross-section, and a current-carrying tip for energizing this wire and guiding it to a welded portion. The cross-sectional shape of the hole was also almost circular. FIG. 5 is a central sectional view of a typical current-carrying tip attached to a conventional GMA welding torch. GM
A guide wire 2 that penetrates the welding tip 1 for A welding has a conductive wire 3 slightly smaller in diameter inserted therethrough. Since the current-carrying wire 3 is fed in a slightly curved state, it was attached to the chips scraped in contact with the tip 4 of the chip, the plating chips whose surface coating film was peeled off, and the current-carrying wire 3. Foreign matter such as dust and rust is conveyed along with the movement of the conducting wire 3 and partly falls from the gap between the guide hole 2 and the conducting wire 3. However, when the guide hole 2 is made thin to improve the contact conducting performance, Since foreign matter accumulates inside the guide hole 2 and the entrance 5, the feed resistance of the current-carrying wire 3 increases,
There is a problem that it often happens that welding cannot be continued, for example, the passage of the current-carrying wire 3 is clogged inside, or a short-circuiting of the arc occurs due to the occurrence of poor current.

[0003] As means for overcoming such problems, Japanese Patent Application Laid-Open No. H11-277242 discloses an energizing tip (energizing contact piece) in which the diameter of the guide hole is increased and the energizing wire is forcibly contacted. The invention of a welding torch in which a good conduction performance can be maintained without forming a curved deformation in the conduction wire by providing a welding torch is disclosed. FIG. 6 is a plan view of the welding torch according to the above-described conventional technique, and FIG. 7 is a cross-sectional view taken along a cutting line CC of FIG.

A ceramic guide tube 10 is provided inside a torch tip member 7 of an energizing member 6 corresponding to the energizing tip shown in FIG.
The power supply wire 3 is inserted into the guide hole 11. An energizing tip 8 is provided, one end of which extends through a through hole formed in the center of the torch tip member 7 and is rotatably supported by a contact portion 12, and has a substantially U-shaped cross section. And is urged by the leaf spring 9 toward the energizing wire 3 so as to straddle the distal end of the ceramic guide tube 10. The other end is located just below the opening and extends in the longitudinal direction of the energizing wire 3. Pressed vertically. The arc current flows from the torch tip member 7 to the conducting wire 3 via the conducting tip 8.

As described above, in the above-described current-carrying member 6, the arc current flows through the current-carrying wire 3 through the current-carrying tip 8, so that the current-carrying wire 3 may be bent or deformed. Since it is not necessary to make the diameter too small, a certain distance can be provided between the energizing wire 3 and the ceramic guide tube 10, and the wire feeding speed unevenness and wire clogging due to foreign matter do not occur. It is possible to maintain stable and stable arc generation and reduce occurrence of spatter.

[0006]

According to the above prior art,
Although this effect can be expected to some extent, when this technique is applied to, for example, the field of robot welding, the current-carrying member 6 disposed at the center of the nozzle (not shown) has a complicated shape with many irregularities. After operating for a long time, the torch tip member 7, energizing tip 8, leaf spring 9
Spatter adheres to and accumulates on the surface of the nozzle and the inner surface of the nozzle, impeding the operation of pressing the energizing tip of the leaf spring 9, lowering the energizing performance by entering the contact energizing portion of the energizing tip 8, and reducing the flow of the shielding gas. A malfunction such as disturbing occurs. The spatter adhered to the surface of each member was difficult to remove due to the complexity of the shape, and as a result, the service life of the current-carrying member 6 was reduced. In addition to this, the temperature of the current-carrying tip 8 that directly receives the arc generated near the current-carrying tip 8 and the radiant heat generated from the molten pool rises, and the wear of the contact portion with the current-carrying wire 3 is more likely to progress. Electricity tip 8
There was also a problem that the service life of the device was shortened accordingly.

A first object of the present invention is to provide an arc welding torch in which spatter does not adhere to a current-carrying tip or the like, or is easily removed even if it adheres, and does not disturb the flow of a shield gas in a nozzle. Is to do. A second object of the present invention is to provide an arc welding torch capable of further reducing the displacement of the leading end of a current-carrying wire.
Further, a third object of the present invention is to provide an arc welding torch capable of reducing wear deterioration of the current-carrying tip by suppressing a rise in temperature of the current-carrying tip.

[0008]

In order to achieve the first object, according to the present invention, an insertion hole through which an energizing wire is inserted is formed at a tip end of the nozzle so as to cover the energizing tip inside the nozzle. A cap having a high thermal conductivity and a smooth curved outer surface is provided at the tip of the torch tip member. In order to achieve the second object, the insertion hole has a non-circular cross section and is formed so as to be formed at least in a ceramic member provided so as to form a tip portion of the cap. Further, in order to achieve the third object, the shielding gas is blown out from the center hole of the torch tip member toward the bottom of the cap, and then inverted and discharged to the outside through the gas discharge hole formed in the upper part of the cap. It is configured to be performed.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a GM according to an embodiment of the present invention.
FIG. 2 is a central sectional view of the vicinity of the tip of the torch for welding A, and FIG.
3 is a cross-sectional view of the vicinity of the tip of the GMA welding torch along the cutting line AA, FIG. 3 is a center sectional view of the cap covering the tip of the GMA welding torch, and FIG. 4 is a cutting line B- of FIG. FIG. 4 is a cross-sectional view of the cap along B.

A rod-shaped torch tip member 22 made of copper is provided with a central hole 23 which penetrates the axis of the rod. A lining 24 is formed on the inside of the central hole 23. Also,
Outside the vicinity of the tip of the torch tip member 22, a pair of recesses 25a, 25b having a semicircular cross section are formed, and these recesses 25a, 25b have rear ends of a pair of conducting chips 26a, 26b. Are rotatably fitted. And these energizing chips 26a,
A pair of leaf springs 27a, 27b are integrally attached to the rear end side outer surface of 26b, and the leaf springs 27a, 27b are screwed to the torch tip member 22, respectively, so that the tips of the current-carrying tips 26a, 26b are Urges the sides inward, and the current-carrying tips 26a, 26b
Are in contact with the conducting wire 3. Energizing tip 26
The basic functions of a and 26b are not so different from those of the conventional example.

The torch tip member 22 is provided with cooling water passages 28a and 28b for circulating cooling water for cooling the rear side substantially along the axis thereof so as to cover the torch tip member 22 and the outside thereof. By communicating with the gap 30 formed between the cylindrical and high heat conductive insulating cylinder 29 made of silicon carbide provided in the cooling water, the cooling water flows back through the gap 30 and the torch tip member 22 The insulating cylinder 29 is directly cooled with water. The space between the torch tip member 22 and the insulating cylinder 29 is sealed by a pair of O-rings 31a and 31b to prevent water leakage. Insulation tube 29
A cylindrical shield nozzle 32 made of copper is fitted on the outside of the housing, and is fastened and fixed by a metal band 33.

At the tip end of the torch tip member 22, a copper-like substantially conical cap 34 whose rear end is screwed to the tip of the insulating tube 29 encloses the current-carrying tips 26a, 26b and the leaf springs 27a, 27b. It is provided as follows. As shown in FIGS. 3 and 4, an insulating and substantially cylindrical ceramic guide cylinder 35 made of silicon nitride is fitted to the center of the tip of the cap 34, and is screwed with a screw 36. In the center of the ceramic guide tube 35, an insertion hole 37 having an equilateral triangular cross-section is in contact with an inscribed circle having a diameter about 0.03 to 0.05 mm larger than the diameter of the energizing wire 3 so that the energizing wire 3 can be easily inserted. Has been drilled.

As described above, since the current-carrying wire 3 is guided by being inserted into the insertion hole 37 of the ceramic guide cylinder 35, the tip position of the current-carrying wire 3 coming out of the insertion hole 37 of the ceramic guide cylinder 35 is restricted. Since the displacement is reduced and a relatively large gap is partially formed between the insertion hole 37 and the conducting wire 3, foreign substances attached to the conducting wire 3 can be discharged therefrom, thereby preventing the occurrence of wire clogging. can do. Eight small gas discharge holes 38a to 38h for evenly discharging the shield gas to the inside of the shield nozzle 32 are formed in the upper portion of the cap 34 at equal intervals along the circumferential direction. The shielding gas is ejected into the cap 34 through the central hole 23 penetrating the shaft core of the torch tip member 22, hits the current-carrying chips 26a, 26b and cools them, and then the bottom of the cap 34 The cap 34 is also cooled in the process of inverting and rising. In addition, the shielding gas is also slightly removed from the gap between the insertion hole 37 and the conducting wire 3.
Although the gas flows out, the gas flow serves to promote the discharge of the foreign matter in the cap 34 from the gap.

The outer shape of the cap 34 has a substantially conical shape formed by a gentle curved surface.
Gas exhaust holes 38a-3 drilled at equal intervals along the circumferential direction of
From 8h, the gas is uniformly discharged to the inside of the shield nozzle 32, so that the flow of the shield gas flowing down inside the shield nozzle 32 is almost undisturbed and uniform.

As described above, in the present embodiment, the conductive chips 26a,
Since 26b is covered with the cap 34, even if spatter occurs during welding, it does not adhere to the current-carrying tips 26a and 26b, and the radiant heat from the arc and molten pool is also reduced.
Since it is blocked by 34 and cooled by the shielding gas, it stops at 150 ° C even if the temperature rises. Further, as described above, since the cap 34 is cooled by the shielding gas, even if the temperature rises, it is at most up to about 200 ° C., and its outer shape is formed with a gentle curved surface, Since the cold shielding gas flows down, the spatter hardly adheres to the cap 34, and even if it adheres, it does not fuse, so that it can be easily removed with a rotating brush or the like.

In this embodiment, the tip of the torch tip member 22 is covered with a copper cap 34, and the ceramic guide tube 35 is fitted to the center of the tip of the cap 34. May fuse,
If spatter removal cleaning is not performed for a long time, a large amount of spatter accumulates here, and the deposited sputter bridges between the current-carrying wire 3 where the arc current is flowing and the cap 34, and Arcs rarely occur.

In order to avoid such a problem, the tip of the torch tip member 22 is covered with a cap made of a non-conductive and high-thermal-conductivity ceramic such as silicon nitride.
With a configuration in which an insertion hole is formed at the distal end, the above-described problem does not occur, and the distal end structure of the welding torch 21 can be simpler. The ceramic guide cylinder 35
The cross-sectional shape of the insertion hole 37 formed in the center of the hole need not necessarily be a triangle, but may be a round hole. When the hole is round, the hole can be easily formed at a low cost. However, since the restraining of the current-carrying wire 3 is loosened, the positional deviation of the tip of the current-carrying wire 3 is slightly increased as compared with the embodiment.

[0018]

As described above, according to the first aspect of the present invention, the insertion hole through which the current-carrying wire is inserted is formed at the tip of the nozzle so as to cover the current-carrying tip inside the nozzle. Since the outer surface of the cap is formed with a smooth curved surface at the tip of the torch tip member, spatter does not adhere to the current-carrying tip, etc. Can be smoothed. According to the second aspect of the present invention, since the insertion hole has a non-circular cross section and is formed at least in a ceramic member provided so as to form a tip portion of the cap, an arc is generated from the cap. Can be prevented, and the positional deviation of the leading end of the conducting wire can be further reduced. According to the third aspect of the invention, the shield gas is blown out from the center hole of the torch tip member toward the bottom of the cap, and then inverted and discharged outside through the gas discharge hole formed in the upper part of the cap. With such a configuration, it is possible to suppress the adhesion of the spatter to the cap and to easily remove the spatter even if it adheres.

[Brief description of the drawings]

FIG. 1 is a central cross-sectional view near the tip of a torch for GMA welding according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the vicinity of the tip of the GMA welding torch taken along the cutting line AA in FIG. 1;

FIG. 3 is a central cross-sectional view of a cap covering a tip portion of a GMA welding torch.

FIG. 4 is a cross-sectional view of the cap taken along section line BB of FIG. 3;

FIG. 5 is a central sectional view of a current-carrying tip of a conventional GMA welding torch.

FIG. 6 is a plan view of a welding torch according to a conventional example.

FIG. 7 is a sectional view taken along section line CC of FIG. 6;

[Explanation of symbols]

 21 Welding torch 22 Torch tip member 23 Center hole 24 Inner lining 25 (a, b) Depressed part 26 (a, b) Current-carrying tip 27 (a, b) Leaf spring 28 (a, b) Cooling water passage 29 Insulating cylinder 30 Gap 31 (a, b) O-ring 32 Shield nozzle 33 Metal band 34 Cap 35 Ceramic guide cylinder 37 Insertion hole 38 Gas exhaust hole

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshiharu Nagashima 5-3 Takara-cho, Kure-shi, Hiroshima Fab-term in Babcock Hitachi Industrial Co., Ltd. 4E001 LA01 LA04 LD20 LE09 LH02 LH03 MB02 MC02 MC05

Claims (3)

[Claims] A central hole penetrating the shaft core and through which a current-carrying wire for consumable electrode arc welding is inserted, and a conductive gas through which the shield gas is guided to a tip end portion. A rod-shaped torch tip member and a tip end of the torch tip member have a rear end portion conductively and rotatably supported, and a tip end portion is urged in a direction in which it comes into contact with the energizing wire led out from the central hole. In the arc welding torch provided with a conductive conductive tip and a cylindrical nozzle that covers the outside of the conductive tip, the conductive wire is provided at the tip so as to cover the conductive tip inside the nozzle. An arc welding torch, characterized in that a cap formed with a through hole to be inserted therein and having a high thermal conductivity and a smooth curved outer surface is provided at the tip of the torch tip member. 2. The insertion hole has a non-circular cross section and is formed in a ceramic member provided so as to form at least a tip portion of a cap.
The described torch for arc welding. 3. A structure in which the shield gas is blown out from the center hole of the torch tip member toward the bottom of the cap, and then inverted and discharged outside through a gas discharge hole formed in the upper portion of the cap. The torch for arc welding according to claim 1, characterized in that: