JPH03174977A - Method and torch for automatic welding of narrow part - Google Patents

Abstract

PURPOSE:To prevent an interference of a welding torch with base metals to be welded and to easily weld a narrow part by providing a straight part on the center and bends which are connected with the straight part and have the almost same size radiuses in the directions to offset each other on both ends of the straight part. CONSTITUTION:The straight part 2 is set in parallel with both inside walls of the narrow part H, in other words, in parallel with a welded joint and automatic welding is performed at the flat or horizontal fillet position. Automatic welding can be performed while the interference of the torch with the base metals W to be welded being prevented by setting the straight part in parallel with the welded joint in this way. In addition, a special short type contact chip of the tip of a nozzle or a welding wire is used in order to meet small bottom width dimensions h.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention is used in a gas shielded arc welding method, etc. to automatically weld a narrow part of a welded joint where the width dimension is small and the depth dimension is large in the welding base material using a torch. The present invention relates to a welding method, and is suitable for use, for example, in automatic gamma welding of the inside of a wheel loader boom shaft mounting bracket or in automatic welding of a wheel loader frame connector.

(Prior Art) Torches used for automated welding are conventionally straight torches consisting of a straight torch body, and single-stage curved torches in which a one-stage curve is formed by curving the torch body at one point.

FIG. 4 schematically shows welding with a straight torch, where a is the straight torch, b is a clamp or holder, C is a nozzle, and d is a wire.

W is the weld base metal, H is the narrow part of the weld joint, and h is the bottom width dimension.
, the depth dimension is denoted by k.

FIG. 5 shows welding using a one-stage curved torch, in which a' is a torch, b' is a clamp or holder, C' is a nozzle, and d' is a wire. The above torch a'
is curved in one direction as shown in R.

(Problem to be solved by the invention) A straight torch a as shown in FIG.
When welding, stable automatic arc welding cannot be performed due to interference with the welding base material W due to severe constraints on the bottom width and depth dimensions.

In addition, when using a single-stage curved torch a' as shown in Fig. 5, there is only one curve R, so the welding wire d' will be bent when the first curve R is applied. As a result, so-called bending of the welding wire occurs, and the fourth
As in the case shown in the figure, stable automatic welding cannot be performed.

It is an object of the present invention to solve the above-mentioned problems.

(Means and effects for solving the problem) The present invention has been made in view of the above points, and has a straight portion in the center, and curved portions are provided at both ends of the straight portion. A two-stage curved torch is formed by a section and two curved sections, and this torch is centered parallel to the welding joint to perform automatic welding with the torch pointing downward or in a horizontal fillet position. By making the radii approximately the same and curving in directions that offset each other, welding wires are not bent, and there is no restriction on the bottom width or depth of the narrow part of the welding joint, making it possible to weld This prevents interference with the base metal and allows automatic welding to be easily performed even on deep welds.

(Example) Next, one embodiment of the present invention will be described based on the drawings.

FIG. 1 schematically shows a case where the torch of the present invention is used to automatically weld a narrow part H of a welded joint where the width dimension of the welding base material W is small and the depth dimension K is large. The figure is an enlarged view of the main parts of the torch shown in FIG.

In these figures, 1 is a torch, and the torch body of the torch 1 includes a straight part 2 having a length L and curved parts 3.4 connected to both ends of the straight part 2, respectively. .4 is the radius R in the direction of mutual cancellation
, R2.

Reference numeral 5 denotes a nozzle provided at the tip of the curved portion 3, 6 a welding wire protruding from the tip of the nozzle 5, 7 a clamp or holder connected to the curved portion 4, and 8 a bracket of a welding robot.

The curves R1 and R2 of the curved portion 3.4 have approximately the same radius R, and by curving in countervailing directions as described above to form a two-stage curve on the torch, welding is possible. The bending of the wire 6 can be alleviated.

When welding is performed using this torch, the straight part 2 is attached to both inner sides of the narrow part H qt (+ -
Hz, that is, parallel to the weld joint, automatically performs welding in a vertical, vertical, downward or horizontal fillet position.

By setting the straight portion parallel to the welding joint in this way, automatic welding can be performed while preventing the torch from interfering with the welding base material W.

Further, the contact tips at the tips of the nozzle 5 and the welding wire 6 are of a special short type in order to cope with the small bottom width dimension.

FIG. 3 is a graph showing the results of welding using the conventional straight torch shown in FIG. 4 and the two-stage curved torch of the present invention shown in FIG. 1, and shows various width and depth dimensions. This shows a comparison of the range in which the torch can be applied to narrow spaces with

The third feature of the torch of this invention is that it is possible to weld deeper joints by making the straight part longer.
It is clear from the diagram.

(Effects of the Invention) The present invention is constructed as described in detail above, and has a straight straight part in the center and radii of approximately the same size at both ends of the straight part in the directions that are connected to the straight part and offset each other. By providing a curved part, a two-stage curved torch is created, and the straight part of the torch is set parallel to the welding joint so that automatic welding can be performed in a downward or horizontal fillet position. To easily weld a narrow part of a welded joint having a narrow bottom width and a deep depth while preventing interference.

Further, the torch is provided with two curves in opposite directions as described above to prevent the welding wire from bending, and by making the straight portion long, it is possible to weld deep joints.

[Brief explanation of drawings]

FIG. 1 schematically shows a case where a narrow gap is automatically welded using a torch according to an embodiment of the present invention. The second cause is an enlarged side view of the torch in FIG. 1, and FIG. Graphs showing the applicable range of the torch and the conventional straight torch, FIGS. 4 and 5, respectively show the conventional torch. Torch...Straight part 4...Curved part

Claims (2)

[Claims] (1) A two-stage curved torch 1 having a straight portion 2 in the center and having curved portions 3 and 4 connected to both ends of the straight portion 2 and having curves in mutually offsetting directions.
, the straight part 2 of the torch 1 is set parallel to the welding joint, and automatic welding is performed in a downward or horizontal fillet position. (2) The two-stage curved torch according to claim (1), wherein the curved portions 3 and 4 have curves with approximately the same radius.