JPH09136165A - Contact tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the a wire rectilinear property and the wire feeding property by making the center hole diameter of an intermediate part larger than the center hole diameter of an inlet side and an outlet side which are advanced in and out with a welding wire, and supporting the wire with both end parts. SOLUTION: A contact tip has a center hole formed by connecting a center hole 11 of a 1st sleeve 10 and a center hole 21 of a 2nd sleeve in the axial direction. The center hole 11 of the top end side and the center hole 21 of the base end side are a normal diameter and the intermediate part is made larger than the normal diameter. Therefore, the welding wire inserted in the center hole is supported with the center holes 11, 21 on both end parts, further, the welding wire is not touched in the intermediate part, the wire rectilinear property and the wire feeding property are more excellent than the same whole length straight hole tip. When the top end part of the contact tip is worn, only the 1st sleeve 10 can be exchanged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact tip attached to the wire outlet of a welding torch.

[0002]

2. Description of the Related Art In gas shielded arc welding, a consumable welding wire wound on a bobbin is supplied to a weld through a welding torch. The welding torch is equipped with a contact tip at the wire outlet to energize the welding wire. The contact tip is a conductive cylindrical body having a wire passage hole called a center hole in the center, and the center hole is usually a straight hole having the same inner diameter over the entire length.
There is also known a two-stage hole structure in which the inner diameter of the inlet portion is larger than the inner diameters of other portions.

[0003]

When the contact tips are compared according to the shape of the inner hole, the straight tip supports the welding wire with its entire length, and therefore, high wire straightness can be maintained for a long time. Excellent wire straightness. However, since the contact resistance between the outer surface of the wire and the inner surface of the chip is large, it becomes difficult to feed the wire in a relatively short time.
Wire feedability is not good. On the other hand, the contact tip of the two-stage hole has a short supporting length of the welding wire, so that the wire straightness is not good, but the wire feeding property is good.

Although it is effective to increase the total length of the contact tip in order to improve the straightness of the wire,
In that case, the wire feedability is deteriorated.

In any case, in the conventional contact tip, it was not possible to achieve both high linearity of wire straightness and wire feedability.

An object of the present invention is to provide a contact tip which is excellent in both wire straightness and wire feedability.

[0007]

The contact tip of the present invention has the intermediate hole diameter of the intermediate portion sandwiched between the inlet end into which the welding wire enters and the outlet end into which the welding wire advances. The diameter of the hole is larger than that of the inlet and the outlet, and the wire feedability is improved without reducing the straightness of the wire.

The inner diameter of the tip is preferably a normal inner diameter slightly larger than the outer diameter of the welding wire at both ends, and 1.2 times or more the normal inner diameter at the middle portion. If the inner diameter of the intermediate portion is small, the inner surface of the tip contacts the outer surface of the wire even at this portion, and the effect of improving the wire feeding property cannot be sufficiently obtained.

The axial length of the intermediate large diameter portion is 0.
3 to 0.8 times is desirable. When the length of the intermediate large diameter portion is reduced, the wire feedability is deteriorated. On the contrary, when the length is increased, the lengths of the normal diameter portions on both ends are relatively reduced, and the inner surface wear of the portions is promoted, so that the function of maintaining the straightness of the wire is deteriorated.

The contact tip of the present invention is mainly used for gas shielded arc welding. The target wire is consumable, and its outer diameter is usually 0.6 to 2.0 mm.

The contact tip of the present invention is also preferably an assembly type in which the contact tip is divided in the axial direction and / or the circumferential direction to be used as a unit. Thereby, it is possible to easily form the intermediate holes having different diameters. From the viewpoint of manufacturability and dimensional accuracy after assembly, it is preferable to use the axially divided type, in which case only the outlet end, which is the end of the exhaustion, that is, only the tip can be replaced, and the economy is also improved. .

[0012]

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

FIG. 1 is a vertical sectional side view showing an example of a contact chip embodying the present invention.

This contact tip is an assembly type which is divided into two parts in the axial direction, and the first sleeve 10 on the outlet side (tip side).
The second sleeve 20 on the inlet side (base end side) is connected by a cap nut type joint 30.

The first sleeve 10 on the front end side has a central hole 11 at its center portion that penetrates in the axial direction. About half of the front end side of the inner hole 11 is a normal diameter portion having a normal inner diameter, and the rest is a large diameter portion having an inner diameter larger than the normal inner diameter. The inner surface of the distal end portion of the inner hole 11 is a rounded tapered surface. An annular convex portion 12 for locking the joint 30 is formed on the inner surface of the sleeve on the proximal end side.

The second sleeve 20 on the base end side has a center hole 21 in the center thereof. About half of the base hole on the base end side has a normal inner diameter, and the rest has a larger diameter than the normal inner diameter. . On the outer surface of the central portion of the second sleeve, the hexagon nut portion 2 is screwed in.
4 are formed. The outer surface on the tip side of the hexagon nut portion 24 is a male screw portion 22 with which the female screw portion 31 of the joint 30 is screwed, and the outer surface on the base end side is a male screw portion 23 for screwing into the welding torch. In order to facilitate the initial insertion of the welding wire on the inner surface of the proximal end portion of the bore 21,
A tapered surface is formed.

First sleeve 10 and second sleeve 20
Is produced by forming a normal diameter part in the central part of the solid body over the entire length and then expanding a part of the normal diameter part to a large diameter part. Then, the manufactured first sleeve 10 is inserted into the joint 30 from the base end side, and the joint 30 is formed with the male screw 22 of the manufactured second sleeve 20.
The first sleeve 10 and the second sleeve 20 are axially connected to each other by assembling into a contact tip.

The assembled contact tip is the first
Medium hole 11 of sleeve 10 and second hole 21 of second sleeve 20
Has a central hole formed in the central portion by being connected in the axial direction. The end of the inner hole on the tip end side and the end on the base end side are normal diameter parts, and the intermediate part sandwiched between both ends is a large diameter part having a larger inner diameter than the normal diameter part.

Such a contact tip has the same wire straightness as a straight hole tip having the same overall length, since the welding wire passed through the inner hole of the contact tip is supported at both ends. Regarding wire feedability, since the welding wire does not contact the tip at the intermediate portion sandwiched by the normal diameter portions at both ends, the performance is superior to the straight hole tip of the same length.

Further, by extending the intermediate portion in the axial direction, it is possible to further improve the wire straightness while maintaining a high wire feeding property. If the tip of the contact tip is worn, only the first sleeve 10 is replaced. Second
Since the sleeve 20 and the joint 30 can be repeatedly used, the economical efficiency is improved.

FIG. 2 is a vertical sectional side view showing another example of the contact chip of the present invention.

This contact tip is a type in which the first sleeve 10 and the second sleeve 20 are directly connected in the axial direction by screwing. First sleeve 10 and second sleeve 20
Hexagon nut portion 24 of the second sleeve 20 for direct connection of
A female screw portion 25 is provided on the inner surface on the more distal side, and the female screw portion 25 is screwed into the male screw portion 13 provided on the outer surface of the base end portion of the first sleeve 10.

About a half of the inner hole 11 of the first sleeve 10 is a normal diameter portion and the rest is a large diameter portion. Second sleeve 2
The middle hole 21 of 0 is provided from the hexagonal nut portion 24 to the base end side. The inner hole 21 has a normal diameter portion and is continuous with the large diameter inner hole of the first sleeve 10 via a tapered portion.

The contact tip of the present invention also has a bore having a normal inner diameter at both ends, and a bore having a large diameter at an intermediate portion sandwiched between the both ends.

FIG. 3 is a vertical sectional view showing still another example of the contact tip of the present invention.

This contact chip is a circumferentially divided type which is divided into two parts on a plane including the center line. Make up a chip 2
Each of the two split pieces 40a, 40b has a U groove 41 for forming a hole in the mating surface and concave and convex portions 42, 43 which are fitted to each other for alignment. It has a male screw portion 44 for mounting. Two U grooves 41
Also in the present contact tip, the inner hole formed by the above has a normal diameter portion at both ends and a large diameter portion at the middle portion.

The present contact tip has an advantage that even if the inner holes have different diameters, the constituent members (splits 40a, 40b) can be easily produced by casting without cutting. This structure can also be applied to conventional straight hole chips and double hole chips. The number of divisions is 2, but
It goes without saying that more than two is possible.

FIG. 4 is a vertical sectional side view showing still another example of the contact chip of the present invention.

The present contact tip comprises a first sleeve 10 and a second sleeve 20 which are axially connected, and the first sleeve 10 on the tip side is divided into two in the circumferential direction. Two split pieces 10 constituting the first sleeve 10
a and 10b are U for forming the inner hole 11 on the mating surface.
It has a groove 16 and concave and convex portions 14 and 15 for positioning, and has a structure in which the base end portion is inserted and connected in the tip end portion of the second sleeve 20 in a state of being combined.

In order to prevent the first sleeve 10 from coming off, a protrusion 17 is provided on the outer surface of the base end portion of the split pieces 10a and 10b, and a groove into which the protrusion 17 is fitted on the inner surface of the distal end portion of the second sleeve 20. 26 are provided. The groove 26 is bent in an L shape or a T shape, and the projection 17 and the groove 26 are aligned with each other and the base end portion of the first sleeve 10 is inserted into the tip end portion of the second sleeve 20 so that the first sleeve 10 is circumferentially moved. The first sleeve 10 is prevented from coming off and is fixed in a united state by rotating the first sleeve 10 into the combined state.

The feature of the present contact tip is that the undivided male screw portion 23 is provided at the base end portion of the second sleeve 20, so that the screw tip is securely screwed into the welding torch as compared with the contact tip of FIG. The second sleeve 20 serves as a fastening member for the first sleeve 10.

Also in the contact chips of FIGS. 3 and 4, the intermediate hole has a large diameter in the middle portion, and the different diameter hole is easily formed by the divided structure of the chip.

In the contact tips of FIGS. 3 and 4, the split piece is appropriately fastened and fixed from the outer surface side by a ring or the like.

In order to confirm the effect of the present invention, the wire straightness and wire feedability of the contact tip of FIG. 1 were investigated and compared with the case of the straight hole tip and the double hole tip. The total length of each chip is 45 mm
And the hole diameter is 1. for a solid wire with a diameter of 1.2 mm.
The normal inner diameter of 4 mm is adopted, and the inner diameter of the large diameter part is 1.
It was set to 2.5 mm, which is 1 mm larger.

In the contact tip of FIG. 1, the first sleeve length was 28 mm, the second sleeve length was 17 mm, the normal diameter portion length on the first sleeve side was 15 mm, and the normal diameter portion length on the second sleeve side was 8 mm. Therefore, the entire chip is 22 mm
The intermediate large diameter part length of is secured. The large diameter portion length of the two-stage hole tip was 22 mm.

Gas shield arc welding was carried out under the conditions of a current of 250 A, a voltage of 30 V and a shield gas CO ₂ (20 liter / min). The straightness of the wire is investigated by measuring the radius of curvature of the wire that has passed through the tip before welding and after 1 hour of welding, and the wire feedability depends on the time (arc continuation time) until an arc break occurs due to poor feed. evaluated.

Similar tests were carried out when the contact tip and the straight hole tip of FIG. 1 were extended to 60 mm in total length. Table 1 shows the results.

[0038]

[Table 1]

As can be seen from the results in Table 1, the chip of the present invention exhibits wire straightness equivalent to that of a straight hole chip of the same length, and the wire feeding property is far superior to the straight hole chip. Further, the straightness of the wire can be further enhanced by maintaining the excellent wire feeding property by extending the tip.

[0040]

As described above, in the contact tip of the present invention, the diameter of the intermediate hole sandwiched between the both ends is made larger than the normal inner diameter, and the wire is supported at both ends, so that the wire goes straight. And the wire feedability can be achieved at a high level.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing an example of a contact chip of the present invention.

FIG. 2 is a vertical cross-sectional side view showing another example of the contact tip of the present invention.

FIG. 3 is a vertical sectional side view showing still another example of the contact tip of the present invention.

FIG. 4 is a vertical sectional side view showing still another example of the contact tip of the present invention.

[Explanation of symbols]

 10 1st sleeve 10a, 10b Split piece 11 Medium hole 20 2nd sleeve 21 Medium hole 30 Joint 40a, 40b Split piece

Claims (1)

[Claims] 1. A medium hole diameter of an intermediate portion sandwiched between an inlet-side end portion into which a welding wire enters and an outlet-side end portion into which the welding wire advances is defined to be larger than the medium hole diameters of the inlet portion and the outlet portion. A contact tip that is characterized by