JP2721276B2 - Power tip for arc welding torch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip for supplying power to a welding wire, such as a curved torch for arc welding and a torch for forced power supply.

[0002]

2. Description of the Related Art In a consumable electrode type arc welding, for example, FIG.
As shown in the figure, the welding wire of the wire reel 1
The welding current is supplied to the welding torch 4 from the feeding tip 5 at the tip of the torch, and a welding current is supplied to the welding wire.
FIG. 4 shows an enlarged cross section of the tip of the torch 4. In FIG. 4, 19 is a connecting tool, 20 is a centering stone, 21
Denotes a tip holder, 23 denotes a nozzle, and 24 denotes a connection nut. FIG. 5A shows an enlarged view of the power supply chip portion. The welding wire 2 projecting from the power supply tip 5 is melted by an arc A generated between the welding wire 2 and the welding base material 6, and welding is performed at a point B. At this time, the welding wire 2 has a bending habit (winding habit) when wound around the wire reel 1, and as shown in FIG. Although it is pressed against the inner surface of the through hole to obtain a contact state necessary for power supply, the tip of the chip 5 comes out curvedly due to a bending habit. At this time, the tip of the feeding point for the wire 2 (the point where the wire 2 is in contact with the chip 5 and closest to the base material 6) is C at the tip of the tip, and the feeding tip 5 is made of a good conductive material such as a copper alloy. Made of conductive material and easy to wear. Accordingly, the inner surface of the through hole for guiding the wire at the tip of the tip gradually wears, and the welding point B gradually shifts toward the wear side as shown in FIG. 5B. As the wear of the tip of the tip progresses, no substantial contact is made at the portion where the curvature of the welding wire 2 becomes equal to the curvature of the tip, so the tip of the feeding point gradually retreats (moves toward the base of the tip). And (b) of FIG.
And C ′ is worn. As described above, the welding point B gradually shifts due to the wear of the inner surface of the through-hole of the tip 5 by the welding wire 2, and the feeding point moves backward. The welding wire 2 is heated by Joule heat generated by the electric resistance and the welding current from the feeding point to the wire tip (the arc generating position). This heated length is called the extension length of the welding wire, and the welding wire 2
Is an important value for the preheating of the steel, and therefore the melting rate, whose variations affect the welding quality. In welding that requires accurate welding positions, such as robot welding, displacement of the welding position due to wear of the tip of the power supply tip 5 poses a problem. Therefore, the power supply tip 5 must be replaced when the wear is relatively small. Often not. For this reason, as shown in FIG. 5C, a wear-resistant member 7 such as a ceramic is attached to the tip of the power supply chip 5 to prevent the tip of the power supply chip 5 from being worn and prolong the life of the power supply chip 5. (For example, Japanese Patent Application Laid-Open No. 62-38771, Japanese Utility Model Application Laid-Open No.
Nos. 0-146578, 61-143770, 62-101673 and 63-63.
2573, JP-A-63-53373, etc.).

[0003]

Although the wear resistance is improved in this way and the life of the power supply chip 5 is extended, the change in extension length caused by wear is insufficiently suppressed. That is, as shown in FIG. 5 (d), the welding wire 2 is positioned by the wear-resistant member 7, and the movement in the direction orthogonal to the wire axis direction is restrained there. A strong wear force is applied to D, which wears in an arc. As the wear becomes deeper, the wear proceeds toward the inside of the chip 5 (original portion side), and the tip of the feeding point moves to the inside of the chip 5. That is, the extension length gradually increases. Here, the length of the wear-resistant member 7 in the direction along the wire axis is L1, the moving speed of the tip of the feeding point is dL / dt,
Assuming that the length from the tip surface of the wear-resistant member 7 to the tip of the welding wire 2 is L0, the rate of change of the extension length per time dt is dL / (L0 + L1 + ∫dL · dt),
The initial value is dL / (L0 + L1), and since L1 is relatively short, the rate of change is large in the initial stage of using the power supply chip (∫dL · dt is small), and as the power supply chip wears, ∫ Since dL · dt increases, it gradually decreases. Thus, the wear-resistant member 7
Has the effect of preventing wear of the tip of the tip 5 and preventing fluctuation of the welding position and improving the welding position accuracy. However, since the initial value of the extension length (L0 + L1) is relatively short, the use of the power supply tip is not necessary. In the initial stage, the electric resistance of the extension length is low and the Joule heat generated by the welding current is small, so that the melting speed of the welding wire (2) is low. In addition, since the initial change rate of the extension length is large, the melting rate fluctuates greatly, and the welding conditions fluctuate, which tends to cause deterioration in welding quality.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the variation in the ekins tension length and to improve the welding position accuracy by improving the wear resistance of the power supply tip and at the same time to stabilize the welding quality.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a welding wire.
(2) a power supply conductor (5a; 5b + 5c) having an inlet opening, an outlet opening through which a welding wire exits, and a through hole (12) for guiding a welding wire continuous with the inlet opening and the outlet opening; The power supply conductor (5a; 5b + 5c) is attached to the outlet side opening, and the through hole (1
(2) a non-conductive wear-resistant member (8) having a through-hole (9) for guiding a welding wire overlapping with the axis center, and a power supply tip (5) of an arc welding torch having: The wear-resistant member
(8) welding wire guiding through hole (9) and the power supply conductor (5a;
A first cavity (11) having a diameter larger than these through holes (9, 12) is formed between the through holes (12) for welding wire guidance of (5b + 5c) .
Further, the feed conductor (5a; 5b + 5c) has a through hole for guiding a welding wire.
Between the through hole (12) and the entrance side opening, a larger than the through hole (12).
Forming a second cavity (15) having a diameter and continuing to the entrance opening
The entrance opening has a diameter larger than that of the second cavity (15) , and the length L1 of the through-hole (9) for guiding the welding wire of the wear-resistant member (8) is 2.5 mm of the welding wire diameter. More than twice, the length L2 of the first cavity (11): more than 5 times the welding wire diameter,
And, feeding conductor; of (5a 5b + 5c) through hole (12) for welding wire induction of
Length L3: characterized by 5mm or more, and the. Symbols in parentheses indicate corresponding elements in the embodiment shown in the drawings and described later.

[0006]

[Action] The welding wire (2) is inserted through the abrasion-resistant member (8).
At (9), the movement of the through hole (9) in the direction perpendicular to the axis is restrained, and the reaction force causes the wire (2) to bend in the direction perpendicular to the direction in which the wire (2) extends in the depth of the through hole (9). Between the through-hole (9) of the wear-resistant member (8) and the through-hole (12) of the feeder conductor (5a; 5b + 5c), the diameter of which is larger than these through-holes (9, 12). Because there is a cavity (11)
The welding wire does not contact the power supply conductor (5a; 5b + 5c) in the cavity (11), but contacts the inner surface of the through hole (12) of the power supply conductor (5a; 5b + 5c). This contact surface gradually wears and the welding wire (2) gradually moves in a direction perpendicular to the through hole (12), but the through hole (12)
Before and after the large diameter first cavity (11), the welding wire
(2) does not contact the power supply conductor (5a; 5b + 5c) except for the through hole (12).

Conventionally, the welding wire (2) first contacts the power supply conductor (5a; 5b + 5c) at the portion (tip) where the cavity (11) was located, and the welding wire (2) first wears out and gradually Although the tip of the feeding point has moved inside, in the present invention, since the welding wire (2) comes into contact with the through hole (12) at the back of the cavity (11), the length of the cavity (11) is reduced. Assuming that L2, the rate of change of the extension length per time dt is dL / (L0 + L1 + L2 + ∫dL · d
t), since the initial value is dL / (L0 + L1 + L2), the rate of change is small from the initial use of the power supply chip (∫dL · dt is small), and ΔdL · dt increases with use, that is, as the wear of the power supply chip progresses. Welding wire to feed conductor (5a; 5b + 5c)
The contact of (2) is limited to the through hole (12). Power supply conductor (5a; 5b + 5
Assuming that the length of the through hole (12) in c) is L3, ∫dL · dt <
L3, and the extension length is (L0 + L1 +
L2) or more and (L0 + L1 + L2 + L3) or less, and the extension length change rate is dL / (L0 + L).
1 + L2) or less.

If the extension length is (L0 + L1 + L
2) or more and not more than (L0 + L1 + L2 + L3), the initial value of which is not less than (L0 + L1 + L2) and longer than that of the conventional one; The melting rate of the welding wire (2) is high because of high heat. That is, a suitable melting rate can be obtained from the initial use of the power supply tip. In addition, as described above, the extension length and the rate of change thereof are maintained within the predetermined ranges, so that the welding conditions are less varied from the initial stage of use, and the welding quality is improved and stabilized. Furthermore, as in the past, the wear-resistant member (8)
However, to prevent wear of the tip of the tip
Maintain high welding position accuracy.

Furthermore, in this onset bright, feed conductor; and (5a 5b + 5c) through hole (12) the length L3 5 mm or more of. This ensures a stable power supply contact. Length of cavity (11,) (L2)
Is 5 times or more the diameter of the welding wire (2). This gives the required extension length and also allows
While the power supply contact at (12) is ensured, it remains non-contact with the welding wire (2). Length L1 of through hole (9) of wear resistant member (8)
Shall be at least 2.5 times the diameter of the welding wire (2). Thereby, welding position accuracy is high. In a preferred embodiment of the present invention, a cone extending from the opening of the through-hole (12) is provided on the inner wall surface of a portion connected to the entrance opening and the exit opening of the through-hole (12) of the power supply conductor (5a; 5b + 5c). The taper is formed in such a manner that the opening angle of the taper is set to be larger at the discharge side (11 side) than at the side at which the welding wire (2) enters (15 side). Since the taper on the entry side is small, the penetration resistance of the welding wire (2) is small, and the taper on the ejection side is large, so that the penetration hole (1) is small.
2) At the tip of the feeding point due to wear of the wire discharge side opening,
The amount of movement in the wire feed direction is small. Abrasion resistant material (8)
Shall have a sleeve with a cavity (11) at the rear end, cut an external thread on the outer periphery of this sleeve, and screw this male screw into the female screw hole at the tip of the power supply conductor (5a, 5b). I do. According to this, the through holes (12) of the power supply conductors (5a, 5b) are worn,
When replacing the power supply tip, the wear-resistant member (8) can be reused. In addition, in a further preferred embodiment of the present invention, the feeder conductors (5b, 5c) are provided with through holes (1
A first power supply conductor (5b) having a sleeve having a female screw hole at the front end for receiving the wear-resistant member (8) and having a large-diameter hole at the rear end; and the sleeve. It shall be composed of a second power supply conductor (5c) having a female screw hole for receiving a male screw on the side peripheral surface and a large diameter hole (15), and the first power supply conductor (5b) is screwed into the second power supply conductor (5c). The power supply conductors (5b, 5c) are integrated. According to this, when the through-hole (12) of the first power supply conductor (5b) is worn out and the power supply chip is replaced, only the first power supply conductor (5b) is replaced, and the wear-resistant member (8) and the second power supply conductor (5) are replaced. (2) The power supply conductor (5c) can be reused.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0011]

FIG. 1 shows an enlarged longitudinal section of a first embodiment of the present invention. FIG. 1A shows the shape of each part of the power supply chip 5,
(B) shows a normal use state through the welding wire 2,
(C) shows a state in which the wear of the through hole 12 has progressed. A roughly cylindrical ceramic chip 8 is provided at the tip of the power supply chip 5.
Is inserted. The ceramic chip 8 is non-conductive so that the ceramic 8 does not supply power to the welding wire 2. When the diameter of the welding wire 2 is 1.2 mm, the diameter of the through hole 9 of the ceramic chip 8 is about 0.1 mm larger than the diameter of the welding wire 2. Power supply chip 5
In order to strictly maintain the directionality of the welding wire 2 irrespective of the wear of the welding wire 2, the length L1 of the parallel portion of the through-hole 9 of the ceramic chip 8 is determined when the diameter of the welding wire 2 is 1.2 mm.
3 mm or more. By doing so, the displacement (blur) in the direction perpendicular to the axis of the welding wire 2 at the position where the extension of the welding wire 2 comes into contact with the base material is reduced to about 1/2 or less of the welding wire diameter, The required position accuracy is satisfied. A tapered surface 14 for facilitating introduction of the welding wire 2 is formed at an opening edge of the ceramic chip 8 on the welding wire entry side. The ceramic chip 8 is fixed to the power supply chip 5 by brazing. It should be noted that another fixing method that can surely maintain the fixing at the use temperature may be used. For example, a screw connection may be used.

The power supply chip 5 has a first cavity 11 continuous with an opening of the ceramic chip 8 on the welding wire entry side, a through hole 12 for supplying power to the welding wire 2, and a second cavity 15. The welding wire 2 is introduced into the second cavity 15 and sent out toward the base material through the through hole 12, the first cavity 11 and the through hole 9 of the ceramic chip 8. First
The length L2 of the cavity 11 defines the shortest value of the extension length. In the case of a welding wire having a diameter of 1.2 mm, a minimum of 6 mm is required.
L2 ≧ 5D. During welding, the welding wire 2 comes into contact with the through hole 12 and the inner surface of the through hole 12 is worn. The diameter of the first cavity 11 is set to a size such that the welding wire 2 does not contact the conductive portion of the power supply tip 5 on the base material side of the through hole 12 while the wear is within the allowable limit. I have. Since the first cavity 11 is intended to allow the welding wire 2 to bend to contact the inner surface of the through hole 12 and to avoid contact with the welding wire 2, the first cavity 11 is formed by elongating the ceramic chip 8. May be. The through hole 12 is a power supply portion to the welding wire 2, and its diameter is slightly larger than the diameter of the welding wire 2. A curved torch in which the welding wire feed path leading to the power supply tip 5 is curved, or a forced power supply type in which a welding wire introduction conduit pipe is bent and urged by a spring to press the welding wire 2 against the power supply tip. To
Since the welding wire 2 is in close contact with the inner surface of the through hole 12, the length L3 of the through hole 12 is sufficient if the diameter of the welding wire 2 is 1.2 mm and 5 mm. Even in the case of a wire, the contact area is increased, so that it is sufficient that the length is 5 mm or more.

The second cavity 15 on the wire entry side of the through hole 12
Is intended to allow some bending of the welding wire 2 and to prevent contact, and its length L4 is determined by the curvature of the welding wire 2 in the curved torch or the shape of the conduit tube in the forced torch. The minimum length may be equal to the length l2 of the first cavity 11. An external thread 16 for fixing the chip 5 to the chip holder 21 (FIG. 4) is formed on the outer peripheral surface of the base where the second cavity 15 is formed.

A tapered surface 14 for facilitating the introduction of the welding wire 2 is provided at the opening edge of the through hole 12 on the welding wire introduction side.
There is. The opening angle θ2 of the taper surface 14 is 30 to 6
It is about 0 degrees. A tapered surface 13 is also provided at the opening edge of the through-hole 12 on the welding wire discharge side. The taper surface 13 is formed when the first cavity 12 is opened.
In order to reduce the advance (movement toward the base material side) of the tip of the power supply point due to the wear of No. 2, the larger the opening angle θ1 is, the better, it is preferably 120 degrees or more. Therefore, the opening angles θ2 and θ1 of the taper surfaces at both ends of the through hole 12 are larger on the discharge side θ1 than on the welding wire entrance side θ2.

FIG. 1B shows an initial state of use of the power supply chip shown in FIG. 1A, and FIG. 1C shows a state in which the inner surface of the through hole 12 has been used considerably for a long time. Since the welding wire 2 is pressed against the inner surface of the through hole 12 by the characteristics of the curved torch or the force feeding type torch, the contact state does not substantially change even if the inner surface of the through hole 12 is worn, and Does not substantially change. That is, the contact resistance and the extension length do not substantially change. Through hole 12
The inclination angle of the welding wire 2 changes at the portion of the first cavity 11 as the inner surface of the ceramic chip 8 wears, but the direction of discharge (delivery) of the welding wire 2 is regulated by the through hole 9 of the ceramic chip 8. The direction in which the welding wire 2 emerges from the ceramic tip 8 toward the base material does not substantially change.

The preferred shape of the power supply tip 5 suitable for a welding wire having a diameter of 1.2 mm is as follows.

A. Ceramic chip 8: A nitride ceramic chip. The diameter of the through hole 9 is 1.3 mm and the length L1 = 3.
mm.

B. Power supply chip 5: made of chromium copper. Length L2 of first cavity 11 = 7 mm, inner diameter 3 mm, through hole 12
Inner diameter 1.3 mm, length L3 = 5 mm, second cavity 1
5, length L4 = 27 mm, inner diameter 3 mm.

FIG. 2A shows a second embodiment of the present invention.
(B) shows a third embodiment. In the second embodiment, the first cavity 11 is formed inside the ceramic chip 8a having a relatively large-diameter sleeve, and external threads are formed on the outer peripheral surface of the sleeve. . A female screw hole for receiving a male screw of the sleeve is formed in the chip body 5a serving as a power supply conductor, and a female screw hole of the ceramic chip 8a is formed therein.
Is screwed. When the inner surface of the through hole 12 of the chip main body 5a becomes too worn, the ceramic chip 8a is removed from the chip main body 5a and the chip 8a is screwed to the new chip main body 5a, and the new chip main body 5a is connected to the chip holder 21 (FIG. 4). Stick to Ceramic chip 8a
Has high abrasion resistance and can thus be reused. In the third embodiment, in order to reduce the disposable portion of the chip main body, the chip main body has a first portion 5 having a through hole 12.
b and a second part 5c having a second cavity 15 and the first part 5b is screwed into the second part 5c. When the inner surface of the through hole 12 of the first portion 5b of the chip main body is greatly worn, the power supply chip 5 is connected to the ceramic chip 8a and the first chip 5a.
The power supply chip 5 is reproduced by replacing the first part 5b with a new one, and the reproduced power supply chip 5 is fixed to the chip holder 21 (FIG. 4). As shown in FIG. 4, the power supply chip 5 is coupled to the chip holder 21 by its screw 16, so that a space corresponding to the second cavity 15 is provided on the chip holder 21 side, and the second part 5c of the third embodiment is provided. May be omitted. In the second embodiment, the second cavity 15 may be omitted, the chip body 5a may be shortened by the length thereof, and the screw 16 may be provided outside the through hole 12. In this case, as in the third embodiment, the through-hole 12
The amount of conductor metal to be discarded due to wear of the metal is reduced.

[0020]

As described above, according to the power supply chip of the present invention, the extension length is long from the initial use of the power supply chip and a stable power supply contact is secured, and the extension length during use is maintained substantially constant. Therefore, the variation in welding conditions such as the melting speed of the welding wire is small, and high-quality welding can be stably performed. In addition, as before,
High welding position accuracy.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view of a first embodiment of the present invention,
(A) shows before use, (b) shows the initial use,
(C) shows a state in which wear has progressed due to long-term use.

FIG. 2 is an enlarged longitudinal sectional view of another embodiment of the present invention;
(A) shows the second embodiment, and (b) shows the third embodiment.

FIG. 3 is a side view showing an outline of a consumable electrode arc welding apparatus.

FIG. 4 is an enlarged vertical sectional view of a tip portion of a conventional arc welding torch.

FIG. 5 is an enlarged longitudinal sectional view of a conventional power supply chip,
(A) shows an initial stage of use of the first conventional example, and (b) shows a state where wear has progressed. (C) shows a state before use of the second conventional example, and (d) shows a state in which abrasion has progressed.

[Explanation of symbols]

1: Reel 2: Welding wire 3: Feeding roller 4: Arc welding torch 5: Feeding tip 5a: Feeding tip body 5b: First part 5c: Second part 6: Base material A: Welding arc B: Welding position 7: Abrasion resistant member 8: Ceramic chip 8a: Ceramic chip 9: Through hole 10: Tapered surface 11: First cavity 12: Through hole 13: Tapered surface 14: tapered surface 15: second cavity 16: screw 19: connecting tool 20: centering stone 21: tip holder 23: nozzle 24: connecting nut

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norihito Kawaguchi 7-6-1 Higashi Narashino, Narashino-shi, Chiba Nippon Steel Welding Industry Co., Ltd. 7-6-1 Nippon Steel Welding Industry Co., Ltd. Equipment Division (72) Inventor Hirohisa Fujiyama 7-6-1 Higashi Narashino, Narashino City, Chiba Nippon Steel Welding Industry Co., Ltd. Equipment Division (56) References JP-A-63-40625 (JP, A) JP-A-61-86082 (JP, A) JP-A-42-17706 (JP, Y1)

Claims (1)

(57) [Claims] A power supply conductor having an inlet opening for receiving a welding wire, an outlet opening from which the welding wire exits, and a through hole for guiding the welding wire continuous with the inlet opening and the outlet opening.
A non-conductive, wear-resistant member having a through hole for guiding a welding wire mounted on the outlet opening of the power supply conductor and overlapping an axis of the through hole. In the power supply tip, a first cavity having a diameter larger than these through holes is formed between the through hole for guiding the welding wire of the wear-resistant member and the through hole for guiding the welding wire of the power supply conductor. And the power supply
Between the through hole for guiding the welding wire of the conductor and the entrance opening
In this case, the diameter of the through hole is larger than that of
Forming a second cavity, the entrance opening of which is larger than the second cavity.
And the length L1 of the through hole for guiding the welding wire of the wear-resistant member is at least 2.5 times the diameter of the welding wire, and the length L2 of the first cavity is at least 5 times the diameter of the welding wire.
Beauty, length of the through hole for welding wire induction of the feed conductor L3: 5 mm or more and that the content has, A - Preparative click welding - Chi the power feed tip.