JPH1133730A - Arc welding torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the welding torch, in which a catalytic electric current is sure, arc cutting is not occur, consumable member is inexpensive and easily replaceable. A generation of chip blockage by a foreign body such as the plating chips is also prevented. SOLUTION: This arc welding torch has on its edge the abrasion resistant guide member 24 with the V-shape groove which guides the wire 5 and the contact piece 31 for the electrification and the wire is held by the guide member and the contact piece by which the wire is electrified. The guide member is fixed to the torch main body and the arc current conductive member 27 which contains the contact piece for the electrification is strengthened by the spring 29 for holding the wire. In addition, the guide member is composed of ceramics of heat-resistance and abrasion resistance. Furthermore, the contact piece for the electrification is installed on the arc current conductive member 27 and it can be detouchable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic arc welding apparatus, and more particularly to an arc welding torch suitable for feeding a wire to a welding portion while stably supplying a current to the welding wire.

[0002]

2. Description of the Related Art Conventional consumable electrode arcs (hereinafter referred to as "GM
A) The cross section of the wire used as an electrode in welding was almost circular in most cases, and the guide hole of the welding tip for energizing the wire and guiding it to the weld was almost circular.

FIG. 17 is a central sectional view showing a conventional typical tip 1 for GMA welding and a guide hole 2 thereof. Usually, the length of the tip 1 is about 45 mm, and the diameter of the guide hole 2 is equal to the diameter of the wire 5 passing through the tip entrance 3.
The diameter of the wire 5 is considerably larger than the diameter of the wire 5 by about 0.1 to 0.2 mm from the middle to the outlet 4, for example. The hole is 0.4 mm. The material of the chip 1 is usually chromium copper, beryllium copper, or the like in terms of wear resistance and conductivity. The wire 5 is fed in a slightly bent state so as to conduct electricity at the tip outlet 4.

FIG. 18 shows a state in which the wire 5 passes through the guide hole 2 of the chip 1 at the cross section of the chip outlet 4, and the inner surface of the guide hole 2 having the circular cross section and the wire 5 having the circular cross section are energized. This is done in a single point of contact.

[0005] In the case of mild steel or the like, the wire is copper-plated to prevent rust and to improve lubricity in feeding. Copper plating that is damaged by the inner surface of the conduit (not shown) that guides the wire from the wire feeder to the welding torch, the inner surface of the welding torch or the contact between the tip and the wire surface, or when passing through the feed roller of the wire feeder May be peeled off, or the wire may be shaved to generate chips. If such chips, plating chips, and dust and rust attached to the wire are collectively referred to as foreign matter, the foreign matter is conveyed by the side of the wire during wire feeding, and the gap between the guide hole and the wire is removed. Some are discharged out of the chip through.

However, when the gap between the guide hole and the surface of the wire is not so large, foreign matter is accumulated before entering the guide hole or in the chip, and the wire gets into the guide hole due to biting of the foreign matter and increase in feeding resistance. It prevents the passage of the wire, or prevents the wire from being energized by contact between the wire and the chip.

[0007] The unevenness of the feeding and the instability of the contact current directly cause an arc breakage in the case of GMA welding, causing problems such as frequent spatters and arc instability. Further, at the start of energization, sparks may be generated between the wire and the chip, and the chip and the wire may be fused.

FIG. 19 shows that the applicant of the present invention discloses Japanese Patent Laid-Open No. 6-3047.
Patent Publication No. 61 discloses a current-carrying chip 13 for GMA
3 shows a cross section of the outlet of FIG. Since the guide hole 14 has an equilateral triangle, the wire 5 contacts the inner surface of the current-carrying tip 13 at two points 9-1 and 9-2. Even if the inscribed circle of the triangle is a value very close to the diameter of the wire, foreign matter is discharged at the corner of the triangle having a sufficient space, so that chip clogging by the foreign matter does not occur.

Although the current-carrying properties are considerably improved by these, the wire diameter becomes larger due to the manufacturing tolerance of the wire diameter, or the cross section of the wire 5 is slightly mechanically deformed by a feed roll of a wire feeder or the like. , Triangular inscribed circle and wire 5
As the gap between them becomes smaller, there is a problem that they are immediately caught in the guide holes 14 and clogged. Therefore, in practical use, the diameter of the triangular inscribed circle must be larger than the nominal wire diameter by at least 0.04 mm in order to secure a gap with the wire 5.

Usually, the current-carrying tip is mounted on a welding torch (not shown), and the torch is used for semi-automatic welding or mounted on a welding robot. When mounted on a welding robot, usually, the wire 5 is taken out of the chip 1 assuming a state at the time of welding prior to welding, and the path is taught by following the welding groove at the tip of the wire, and then played back. And perform the welding. However, at the time of playback, the gap between the guide hole 2 and the wire 5 or the bending direction of the wire 5 as shown in FIG. It may come off or meander during welding to cause poor welding.

Therefore, it is desirable that the wire 5 exits from the guide hole which is as straight as possible and has a small gap. Therefore, for the wire 5, a wire in a pail can having a larger radius of curvature of the wire 5 is used. However, when the straight wire 5 is passed through the straight guide hole 2, there arises a problem that the contact energizing position in the guide hole becomes unstable.

Therefore, when a straight wire 5 is employed, there is an example in which the wire 5 is pressed against the surface of the current-carrying guide hole by a spring from the side (Japanese Patent Application Laid-Open No. 64-18582).

FIG. 20 is a view for explaining the present invention, in which a structure is adopted in which the wire 5 is pressed against the inner surface of the hole of the chip 1 by the leaf spring 11 via the pressure contact slider 10. Pressure contact slider 1
This publication discloses that when metallic carbon is used as the material 0 and a conductive material is used as the leaf spring 11, the wire 5 is also energized through the leaf spring 11, but the energization is mainly performed on the inner surface of the chip. It is speculated that this is done by:
This structure has a problem that when the wear of the chip 1 progresses, the entire complex and expensive chip 1 must be replaced.

On the other hand, in order to smoothly discharge foreign matter, Japanese Utility Model Publication No. Sho 56-142880 discloses a space 8 and a lateral hole 6 in the middle of a guide hole in a current-carrying chip as shown in FIG.
And proposes a structure for discharging foreign matter therefrom.
However, even with this method, if the hole diameter of the tip at the tip is smaller than the normal value, clogging will still occur if there is cross-sectional deformation or local bending of the wire, so the guide hole diameter itself must be larger than the wire diameter, Therefore, the gap with the wire 5 in the guide hole related to the contact energization is not particularly improved.

[0015]

In the above prior art, there is a problem that the gap between the wire and the guide hole is relatively large, the position of the tip of the wire fluctuates considerably, and the contact current becomes unstable. Further, the method of discharging foreign matter from a lateral hole or the like provided in a chip has a problem that a complicated chip structure is required and the chip becomes expensive, and a chip is clogged due to deformation of a wire itself.

Further, in the case of a normal energizing tip, since the guide hole is circular, the number of contact energizing points is one. Therefore, there has been a problem that arc breakage due to instantaneous energizing failure is likely to occur. The countermeasure against the inner surface of the chip with a spring from the side as a countermeasure is an expensive consumable member with a complicated structure, and is not a countermeasure against the chip.

An object of the present invention is to provide means for solving all of the above problems. That is, the object of the present invention is to
Even if a wire with a large radius of curvature is used, contact energization is performed reliably and no arc break occurs, the position of the tip of the wire where the arc is generated changes little, and consumable members are inexpensive and easy to replace. Another object of the present invention is to provide a welding torch having a function of preventing chip clogging due to foreign matter such as plating dust or slight change in the wire cross-sectional shape.

[0018]

In order to solve the above problems, the present invention mainly employs the following configuration.

In the torch for arc welding, a wear-resistant guide member provided with a V-groove for guiding a wire at the foremost part of the torch, and a contact for energization at the foremost part of the torch are arranged. An arc welding torch configured to sandwich the wire between the guide member and the energizing contact so as to energize the wire from the energizing contact.

Further, the guide member is an arc welding torch made of heat resistant and wear resistant ceramics.

Further, the guide member is made of a super-hard metal, and an abrasion-resistant and electrically insulating film is formed on the entire surface except for the V-groove, and is insulated from the torch main body.

Further, the arc welding torch is provided on the arc current conducting member and has a detachable structure.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a tip for a GMA welding torch according to the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a chip 20 according to the present invention, and FIGS. 2 to 6 are sectional views taken along lines AA to EE of FIG. FIG.
Is a diagram showing only the chip body 21. 8 and 9 are views showing the V-groove member 24. FIG. 10, 11, and 1
FIG. 2 is a view showing the conducting member 27.

Here, 5 is a wire, 20 is a chip, 21 is a chip body, 22 is a screw, 23 is a guide hole, 24 is a V-groove member, 25 is a flat bottom groove, 26 is a round groove, and 27 is a round groove.
Is a conducting member, 28 is a cut, 29 is a leaf spring, 30 is V
The groove, 31 indicates a contact for energization, and 32 indicates a flat bottom groove.

In FIG. 1, reference numeral 21 denotes a tip body for a wire having a diameter of 1.2 mm, which is made of chromium copper similarly to a conventional tip, and is connected to a torch body (not shown) with screws 22.
Although it is a conductor for conducting arc current, it has a length of about 70
A cylinder having a diameter of about 12 mm and a diameter of about 12 mm is subjected to various cutting processes, and a wire guide hole 23 having a diameter of 2 mm is provided in the center axis direction.

A flat bottom groove 25 for embedding a V-groove member 24 made of silicon nitride having excellent heat resistance and abrasion resistance is formed at the tip of the chip body 21. Further, a round groove 26 is provided in the center portion of the chip body 21 in the lateral direction, and a current-carrying member 27 is inserted therein and hooked.
Further, a notch 28 is provided, and a width 6 mm and a thickness 0.6 are provided there.
The current-carrying member 27 is pressed against the chip body 21 by inserting a heat-resistant leaf spring 29 made of an extension hardening stainless steel having a thickness of 2 mm.

FIG. 7 is a diagram showing only the chip body 21 as viewed from the left side of FIG. FIG. 8 is a plan view of the V-groove member 24, and FIG. 9 is a front view thereof. For a wire having a diameter of 1.2 mm, a V groove 30 having a depth of 1.2 mm and 60 degrees is provided on the surface. When a 1.2 mm wire is pressed into the V-groove, the wire comes into two-point contact with the V-groove and protrudes from the member surface by a height of 0.6 mm. The V-groove member 24 is fitted in a T-shaped flat bottom groove 25 of the chip body 21.

FIG. 10 is a plan view of the conducting member 27 as viewed from the right side of FIG. The conducting member 27 is made of chrome copper of the same material as the chip body. FIG. 11 is a plan view of the energizing contact 31, and FIG. 12 is a front view thereof. The current-carrying contact 31 is a wear-resistant current-carrying member made of copper tungsten, and has a T-shaped flat bottom groove 32 provided in the current-carrying member 27.
Use it by fitting it inside. This energizing contact is shown in FIG.
As shown in FIG. 6, about 1 mm from the conducting member 27 to the wire side.
It has a thickness that protrudes.

The chip 20 is composed of the components described above, and is assembled as shown in FIG. 1 and operates as follows. The wire 5 is fed into the wire guide hole 23 of the chip 20 from the screw portion 22 side connected to the torch main body portion (not shown). The contact 31 passes through a place where the contact 31 is slightly pressed by the leaf spring 29 toward the V-groove member 24 via the conducting member 27, exits the tip 20 and reaches the welded portion.

Since the current-carrying member 27 is pressed by the leaf spring 29, it is held in contact with the round groove 26 via the current-carrying contact 31 by the wire. The wire 5 is energized from the round groove 26 through the energizing member 27 and the energizing contact 31. Since the wire 5 is always sent out from the chip 20 while being pressed against the V-groove 30 by the current-carrying contact 31, there is no gap between the guide hole and the wire seen in the conventional chip, and the wire exit position is determined. For this reason, the displacement of the wire tip aiming position is further reduced. Further, even if the wire 5 is not bent, since the contact current is always supplied by the current supply contact 31, no arc breakage due to poor current supply occurs.

In the present embodiment, two members, namely, the current-carrying member 27 and the current-carrying contact 31 are used, but they may be integrated into one member. Although the cost of consumable members increases, the number of contact current-carrying parts is reduced by one, and the current-carrying is more stabilized.

Next, a second embodiment of a tip for a GMA welding torch according to the present invention will be described with reference to the drawings. FIG.
3 is a central sectional view of the chip 33 according to the present invention, and FIGS. 14 to 16 are sectional views taken along lines AA to CC of FIG.

In FIG. 13, reference numeral 34 denotes a 45 mm long chip body made of chrome copper for 1.2 mm wire.
It is connected to a torch main body (not shown) by screws 35, and serves as a conductor through which arc current flows. Chip body 34
The wire exit side has a shape in which a wide concave groove is engraved in a square having a side of 10 mm as shown in FIGS. 14 and 15, and a tip having a head diameter of 8 mm as shown in FIG. A round hole 37 is provided for receiving a pin-shaped conductive contact 36 made of copper tungsten.

Reference numeral 38 denotes a heat-resistant material having a general outer shape of 8 × 5 × 32 mm.
A V-groove member made of silicon nitride having excellent wear resistance, which is fitted on the wire exit side of the chip body 34. That is, the V-groove member 38 for guiding the wire is the same as that shown in FIGS.
As shown in FIG. 5, a pin 40 which is fitted in the U-shaped groove 39 of the outer surface groove and penetrates through the chip body portion 34 and which can be easily inserted and removed is made of a heat-resistant nickel alloy shown in FIGS. Two compression springs 4 having a diameter of 3 mm
The wires 1 and 42 have a structure in which the wire 5 is pressed against the current-carrying contact 36 at the tip outlet side so as to sandwich the wire 5 therebetween.

Therefore, the wire 5 is fed into the wire guide hole 43 of the tip 33 from the screw portion 35 connected to the torch main body (not shown). Then, the V-groove member 38 passes through a place where the V-groove member 38 is lightly pressed by the compression springs 41 and 42 and the pin 40 toward the current-carrying contact 36, exits the tip 33 and reaches the welded portion. For this reason, since the wire is always in contact with the current-carrying contact, there is no occurrence of arc breakage.

Compared with the case of the first embodiment, since the light V-groove member 38 is only pressed lightly, the pressing force against the wire is stable, so that the pressing force can be reduced. There is an advantage in that the contact can be supplied directly from the chip main body without passing through, so that it is more preferable from the viewpoint of current supply stability.On the other hand, since the current supply contact, which is a consumable member, is fixed, There is also a disadvantage that the target position of the distal end of the wire 5 is slightly changed as the contact 36 is worn.

In the first and second embodiments, the V-groove member 2
4, 38 used electrically insulating silicon nitride. But V
The groove member 24 is not limited to an insulating material. Even when conductive tool steel (SKD11) was used as the V-groove members 24 and 38, a considerable wear life was exhibited. However, when the wire is not energized from the V-groove side, the wear life is prolonged because spark does not occur and the like.
Therefore, a V-groove member is made of hard tool steel, and an abrasion-resistant and electrically insulating film made of a TiAlN film is formed by ion plating on the entire surface excluding the V-groove portion.
A longer service life is obtained by using a structure that insulates from the contact and that the current is supplied only from the current-carrying contact.

Although the wear life is slightly inferior to that of silicon nitride, such a V-groove member using tool steel has an advantage that it can be manufactured more easily than silicon nitride and can be less expensive.

Further, it goes without saying that the grooves of the V-groove members 24 and 38 are not actually limited to the V-grooves, but include groove shapes that can be substituted, such as round bottom grooves that can guide the wire stably.

In the first and second embodiments, the tip bodies 21 and 34 are fixed to the welding torch via the screw parts 22 and 35, but the tip bodies 21 and 3 are fixed.
Since 4 is hardly worn, it can be directly incorporated in the torch main body.

As described above, the present invention includes the one having the following configuration and function.

In the torch for arc welding, a wear-resistant guide member provided with a V-groove for guiding a wire at the tip of the torch, and a contact for energization at the tip of the torch are also placed. The structure is such that the wire is energized from the energizing contact while the wire is sandwiched between the energizing contact.

At this time, a wear-resistant guide member having a V-groove for guiding the wire may be fixed to the torch main body, and the member on the side of the current-carrying contact may be moved by a spring to sandwich the wire. Alternatively, the member on the side of the current-carrying contact may be fixed to the torch main body, and a wear-resistant guide member provided with a V-groove for guiding the wire may be moved by a spring to sandwich the wire.

A guide member provided with a V-groove for guiding a wire is made of heat-resistant and wear-resistant ceramic or super-hard metal, or a hard metal surface coated with a wear-resistant and insulating film. It consists of.
The current-carrying contact has an easy-to-remove structure in which it is pressed against the V-groove member by the arc-current-carrying terminal member, and its wire-pressing surface has a flat surface or a structure provided with a V-groove or slit. .

A triangular shape in close contact with the outer diameter of the wire is formed of the V groove and the energizing contact in such a manner that the wire is pressed against the V groove, and a gap is formed along both sides of the wire along the wire.
This gap is much larger than a normal circular guide hole, and functions as a gap for discharging foreign matters.

The displacement of the wire tip position is reduced by the absence of the gap between the guide hole and the wire.
The V-groove side does not wear, so it is fixed and there is no change. Even on the contact side, if the tip is worn locally due to wire bending, the effect of wire bending only appears. In the case of wear on average, the contact is pressed against the V-groove by the spring, so that there is no effect on the wire bending.

Since the current-carrying contact has a structure in which it is always pressed against the wire by a spring even if it is slightly worn, stable contact current is maintained and faulty current is provided as compared with a normal round hole current-carrying tip. In addition, no arc breakage occurs due to the above, and no spark is generated between the wire and the tip when the arc is started, so that the tip and the wire are not fused, and the wear life is increased and the life is extended. Although the current-carrying contact is a consumable member, it is made of a small-sized copper alloy or the like that is easy to manufacture, so that the cost of the consumable member can be extremely low as compared with a conventional current-carrying chip.

[0048]

The V-groove member is made of silicon nitride or the like having excellent heat resistance and abrasion resistance, so that it is hardly worn. Even if the chip body is slightly worn, there is essentially no problem. No replacement is required.

Although the current-carrying contact is made of copper tungsten having excellent wear resistance, the contact gradually wears. However, since the spring is pressed down even if it is slightly worn, the power is always supplied until the depth of the groove formed by the abrasion formed on the current-carrying contact becomes deeper than the wire portion protruding from the V-groove. Due to the structure, the wear life is increased about five times as compared with the conventional tip.

When the life has expired due to poor energization,
It is sufficient to replace only a small current-carrying contact, and expensive copper tungsten is used. However, since the shape is simple and the weight is small, the cost is low.

The guide hole is sufficiently large even if foreign matter such as copper plating debris or wire chips is conveyed to the wire and enters the chip. Since the wire is sandwiched between the contacts to form a sufficiently large space in the lateral direction, foreign matter is discharged from there,
No clogging of chips.

It is preferable that the depth of the V-groove of the V-groove member is equal to the diameter of the wire to be used. Wires from 1.0 mm to 1.6 mm could be used. That is, according to the present invention, the three sides of the triangle formed by the V groove and one plane are pressed so as to be in close contact with the outer periphery of the wire.
Compared to the case of using a triangular hole tip manufactured so as to have an inscribed circle having a diameter larger by mm, there is an effect that the wire insertion position is stable and the welding operation is more stable.

In the case of the conventional energizing tip, one tip can be applied to only one nominal wire diameter. However, according to the present invention, the range of the nominal wire diameter applicable to one V-groove member is widened. ing.

The tip of the present invention has a very versatile structure, so that, for example, even if the wire is slightly bent locally or the cross section is slightly deformed locally, the tip is operated by the spring. Because the holding contact is pushed back through the wire, the chances of wire jamming due to these causes seen with conventional round hole tips are greatly reduced.

The ceramic member constituting the V-groove member can be formed by simply cutting the green body, or can be formed by a simple mold that can be manufactured at low cost. Further, since the energizing contact may be basically in the form of a flat plate, it is easy to manufacture. The tolerance range of the production required for these members can be considerably increased, and the production yield is good.

As described above, according to the present invention, since the current supply to the wire is stable, the occurrence of spatter is reduced, the chip is not clogged, the chip life is long, and the change of the target position of the wire tip is changed. It is possible to provide an economical welding torch with less.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a welding tip according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along the line CC of FIG. 1;

FIG. 5 is a sectional view taken along line DD of FIG. 1;

FIG. 6 is a sectional view taken along the line EE of FIG. 1;

FIG. 7 is a configuration diagram of a tip body portion of the welding tip according to the first embodiment of the present invention.

FIG. 8 is a plan view of a V-groove member.

FIG. 9 is a front view of a V-groove member.

FIG. 10 is a plan view of an energizing member.

FIG. 11 is a plan view of an energizing contact.

FIG. 12 is a front view of an energizing contact.

FIG. 13 is a sectional view showing a second embodiment of the welding tip according to the present invention.

FIG. 14 is a sectional view taken along line AA of FIG.

FIG. 15 is a sectional view taken along line BB of FIG.

FIG. 16 is a sectional view taken along line CC of FIG.

FIG. 17 is a longitudinal sectional view of a conventional welding tip.

FIG. 18 is a transverse sectional view showing a state where a wire is passed through the welding tip of FIG. 17;

FIG. 19 is a cross-sectional view of a conventional welding tip according to Japanese Patent Application Laid-Open No. Hei 6-304761.

FIG. 20 is a longitudinal sectional view of a welding tip according to a conventional example of Japanese Patent Application Laid-Open No. 64-18582.

FIG. 21 is a longitudinal sectional view of a welding tip according to a conventional example of Japanese Utility Model Publication No. 56-142880.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 GMA welding tip 2 Guide hole 3 Inlet part 4 Outlet part 5 Wire 6 Side hole 7 Electricity tip 8 Gap 9 Contact energization point 10 Slider 11 Leaf spring 12 Screw 13 Electricity tip 14 Guide hole 20, 33 Chip 21, 34 Chip Main body 22, 35 Screw 23, 43 Guide hole 24, 38 V groove member 25 Flat bottom groove 26 Round groove 27 Current supply member 28 Cut 29 Leaf spring 30 V groove 31, 36 Current supply contact 32 Flat bottom groove 39 U groove 41, 42 Compression spring

Continuing from the front page (72) Inventor Toshiharu Nagashima 5-3 Takara-cho, Kure-shi, Hiroshima Prefecture Inside Bab Hitachi Industrial Co., Ltd. (72) Inventor Mitsuhiro 5-3 Takara-cho, Kure-shi Hiroshima Prefecture Inside Bab Hitachi Industrial Co., Ltd.

Claims (7)

[Claims] 1. A torch for arc welding, comprising: a wear-resistant guide member having a V-groove for guiding a wire at a foremost portion of the torch; and a contact for energization at a foremost portion of the torch. An arc welding torch, wherein the arc welding torch is arranged so that the wire is sandwiched between the guide member and the energizing contact, and the wire is energized from the energizing contact. 2. The arc welding torch according to claim 1, wherein said guide member is fixed to a torch main body, and an arc current energizing member provided with said energizing contact is biased by a spring to sandwich said wire. Arc welding torch. 3. The arc welding torch according to claim 2, wherein the arc current conducting member is configured to be biased by a spring so as to conduct current to the torch body side. 4. The arc welding torch according to claim 1, wherein an arc current energizing member provided with the energizing contact is fixed to a torch body, and the guide member is biased by a spring to clamp the wire. Arc welding torch. 5. The arc welding torch according to claim 1, wherein the guide member is made of heat-resistant and wear-resistant ceramic. 6. The arc welding torch according to claim 1, wherein the guide member is made of a super-hard metal.
An arc welding torch characterized in that an abrasion-resistant and electrically insulating film is formed on the entire surface excluding a groove and is insulated from a torch body. 7. The arc welding torch according to claim 1, wherein the current-carrying contact is provided on an arc current-carrying member and has a removable structure.