JP6372797B2 - Laser welding nozzle - Google Patents

Description

  The present invention relates to a laser welding nozzle that performs welding by irradiating a metal material with a laser beam while spraying a shield gas, and a shield gas guide member for guiding the shield gas to a welding location.

  When performing laser welding, it is common to irradiate a laser beam while spraying a shielding gas in order to prevent oxidation of the welded portion. As a method for spraying shield gas to the welded portion, a method called a side nozzle method and a method called a nozzle internal shield method have been proposed. In the side nozzle method, shield gas is injected from a side nozzle provided separately from a laser welding nozzle that emits laser light, and the side nozzle shields the welded part while moving following the laser welding nozzle. Inject gas. On the other hand, in the in-nozzle shield method, a shield gas is supplied to a laser welding nozzle, and laser light is emitted from a nozzle hole of the laser welding nozzle and a shield gas is injected (see, for example, Patent Document 1).

JP 2013-215801 A

  In the conventional side nozzle method, when the welding member has a complicated three-dimensional shape, the side nozzle interferes with the welding member, and it is difficult to properly inject the shielding gas toward the welded portion. there were.

  Further, the conventional shield method in the nozzle has a problem that a sufficient shield range cannot be secured and oxidation of the welded portion cannot be prevented satisfactorily.

  An object of the present invention is to provide a laser welding nozzle and a shield gas guide member that can inject a shield gas well toward a welded portion.

  The nozzle for laser welding according to claim 1 of the present invention is a laser welding nozzle that performs welding by irradiating a welding member with laser light, and includes a cylindrical inner nozzle that allows laser light to pass therethrough, and the inner nozzle. A nozzle cover that covers the periphery of the nozzle cover, and a top nozzle mounted at the tip of the nozzle cover, and an annular gas path through which a shielding gas passes is defined between the inner nozzle and the nozzle cover, A nozzle hole is formed in the top nozzle, laser light passes through the inner space of the inner nozzle and is emitted from the nozzle hole of the top nozzle, and shielding gas passes through the annular gas path and passes through the annular nozzle. It is sprayed from the nozzle hole, and the tip portion of the nozzle hole is formed in a tapered shape whose inner diameter gradually increases toward the tip. And butterflies.

  In the laser welding nozzle according to claim 2 of the present invention, a gas supply hole for supplying a shield gas from the outside to the gas path is formed in the nozzle cover, and a central axis of the gas supply hole is The nozzle cover is inclined in a direction approaching the central axis of the gas path toward the tip of the nozzle hole, and is inclined with respect to a tangent to the outer peripheral surface of the nozzle cover.

  The nozzle for laser welding according to claim 3 of the present invention further includes a shielding plate that covers the opening on the proximal end side of the inner nozzle, and a block member is disposed inside the inner nozzle. Has a through hole for allowing the laser beam to pass therethrough.

  According to a fourth aspect of the present invention, in the laser welding nozzle, an auxiliary nozzle hole that communicates the nozzle hole with the outside is formed in a rear side wall portion of the top nozzle in the laser welding nozzle traveling direction. A part of the shielding gas supplied to the nozzle is jetted from the auxiliary nozzle hole toward the rear in the laser welding nozzle traveling direction.

  The nozzle for laser welding according to claim 5 of the present invention is characterized in that an auxiliary nozzle for injecting a shielding gas toward the rear in the laser welding nozzle traveling direction is attached to the outer surface of the top nozzle. And

  The nozzle for laser welding according to claim 6 of the present invention is characterized in that a guide extending spirally is provided in at least one of the gas path and the nozzle hole.

  According to the laser welding nozzle of the first aspect of the present invention, since the tip portion of the nozzle hole is formed in a tapered shape whose inner diameter gradually increases toward the tip, the shield gas injected from the nozzle hole It is possible to widen the shield range, and it is possible to satisfactorily prevent the welded portion from being oxidized. Further, since the shielding gas from the outside is supplied to the nozzle hole via the annular gas path, it is rectified while passing through the gas path, and easily flows along the inner wall of the nozzle hole, thereby further expanding the shielding range. be able to.

  According to the laser welding nozzle of the second aspect of the present invention, since the central axis of the gas supply hole is inclined in a direction approaching the central axis of the gas path toward the tip of the nozzle hole, the nozzle is directed toward the nozzle hole. The shield gas can be supplied smoothly. Further, since the central axis of the gas supply hole is inclined with respect to the tangent to the outer peripheral surface of the nozzle cover, the shield gas flows spirally along the circumferential direction of the gas path, and the shield gas injected from the nozzle hole It becomes easy to spread around, and the shield range can be expanded.

  According to the laser welding nozzle of claim 3 of the present invention, since the shielding plate that covers the proximal end side opening of the inner nozzle is provided, the inner space of the inner nozzle is isolated from the cross jet space, and the cross jet space is It is possible to prevent the shield gas from being caught by the flowing cross jet airflow, and the shield gas can be reliably injected from the nozzle hole. Further, since the block member is disposed inside the inner nozzle, even if the spatter enters the inside, the spatter is blocked by the block member and prevented from reaching the shielding plate. Furthermore, since the through hole for allowing the laser beam to pass through is formed in the block member, the block member is not damaged by the laser beam. Further, since the laser light passes through the through hole, even if spatter adheres to the block member, the laser light irradiation is not affected.

  According to the laser welding nozzle of claim 4 of the present invention, since the auxiliary nozzle hole is formed in the laser welding nozzle rear side wall portion of the top nozzle, the shield gas supplied to the nozzle hole A part is injected toward the rear in the nozzle traveling direction from the auxiliary nozzle hole, so that the shield range on the rear side in the nozzle traveling direction can be widened, and oxidation of the welded portion can be prevented better.

  According to the laser welding nozzle of claim 5 of the present invention, since the auxiliary nozzle for injecting the shielding gas toward the rear of the laser welding nozzle traveling direction is attached to the outer surface of the top nozzle, By spraying the shield gas from the auxiliary nozzle, the shield range on the rear side in the nozzle traveling direction can be expanded, and oxidation of the welded portion can be prevented more favorably.

  According to the laser welding nozzle of the sixth aspect of the present invention, since the guide extending spirally is provided in at least one of the gas path and the nozzle hole, the nozzle flows in a spiral manner along the guide. The shield gas sprayed from the nozzle holes can easily spread to the surroundings, and the shield range can be expanded.

The front view which shows the laser welding head which has the nozzle for laser welding which concerns on 1st Embodiment of this invention. The front view which shows the nozzle for laser welding shown in FIG. III-III sectional view taken on the line of FIG. FIG. 4 is an exploded view of the laser welding nozzle shown in FIG. 3. FIG. 3 is a cross-sectional perspective view of the laser welding nozzle shown in FIG. 2. FIG. 6 is a sectional view taken along line VI-VI in FIG. 2. The side view which shows the nozzle for laser welding which concerns on 2nd Embodiment of this invention. FIG. 8 is a cross-sectional perspective view taken along line VIII-VIII in FIG. 7. Sectional drawing which shows the nozzle for laser welding which concerns on 3rd Embodiment of this invention. The cross-sectional perspective view which shows the shield gas guide member which concerns on 4th Embodiment of this invention. The bottom view of the pressing member with which the shield gas guide member shown in FIG. 10 is provided. XII-XII sectional view taken on the line of FIG. XIII-XIII sectional view taken on the line of FIG. The disassembled perspective view of the pressing member shown in FIG. The cross-sectional perspective view which shows the inner nozzle with which the nozzle for laser welding which concerns on the modification of this invention is provided. The cross-sectional perspective view which shows the top nozzle with which the nozzle for laser welding which concerns on the modification of this invention is provided.

[First Embodiment]
Hereinafter, a laser welding nozzle according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a laser welding head having a laser welding nozzle according to this embodiment.

Referring to FIG. 1, a laser welding head 1 includes a head main body 2 and a laser welding nozzle 3 that is detachably attached to the distal end side (lower side) of the head main body 2. The head body 2 supports a condensing lens (not shown) for condensing the laser light, a protective lens (not shown) for protecting the condensing lens, and the like. The nozzle 3 for laser welding is provided with a nozzle hole N1, from which laser light condensed by a condenser lens is emitted and a shield supplied from a shield gas supply device (not shown). Gas is injected. As the shielding gas, for example, nitrogen or argon gas is used. Further, between the head body 2 and the laser welding nozzle 3, a cross jet space S, which is a passage path of the cross jet airflow, is provided.

  2 to 4, the laser welding nozzle 3 includes an inner nozzle 4, a nozzle cover 5 that covers the periphery of the inner nozzle 4, a top nozzle 6 that is attached to the tip of the nozzle cover 5, and a nozzle cover. And a shielding plate 7 accommodated and held in the housing 5.

  The inner nozzle 4 is formed in a cylindrical shape, and block members 42 and 43 are disposed in the inner space 41 thereof. Through holes 42 a and 43 a for allowing laser light to pass therethrough are formed at the center of the block members 42 and 43. These through holes 42a and 43a have a larger diameter in the through hole 42a located on the proximal end side than the through hole 43a located on the distal end side so that the block members 42 and 43 do not interfere with the laser beam. ing.

  The nozzle cover 5 is formed in a cylindrical shape that can accommodate the inner nozzle 4, and an annular step portion 51 that protrudes radially outward is formed at a base end portion thereof. In the nozzle cover 5, the outer peripheral surface 44 of the proximal end portion of the inner nozzle 4 accommodated therein is in surface contact with the inner peripheral surface of the nozzle cover 5, while the inner diameter of the distal end portion of the nozzle cover 5 is the inner nozzle 4. Thus, an annular gap (gas path) 52 having an open front end is formed between the inner nozzle 4 and the nozzle cover 5.

  The nozzle cover 5 is provided with a plurality of gas supply holes 53 connected to a gas supply pipe (not shown) of the shield gas supply device at intervals in the circumferential direction. Referring also to FIG. 5 and FIG. 6, each gas supply hole 53 is inclined in a direction closer to the central axis C <b> 2 of the laser welding nozzle 3 (gas path 52) as its central axis C <b> 1 moves toward the tip (downward). At the same time, the nozzle cover 5 extends inclining with respect to the tangent line T of the outer peripheral surface 54 and communicates with the gas path 52.

  The top nozzle 6 is formed in a cylindrical shape and is detachably attached to the tip of the nozzle cover 5. In the present embodiment, a thread groove is formed on the base end side outer peripheral surface of the top nozzle 6, and is configured to be screwed with a screw groove formed on the tip end inner peripheral surface of the nozzle cover 5. Inside the top nozzle 6 is formed a nozzle hole N1 through which the laser beam and the shield gas described above pass, and this nozzle hole N1 communicates with the internal space 41 and the gas path 52 of the inner nozzle 4. The tip portion of the nozzle hole N1 is formed in a tapered shape whose inner diameter gradually increases toward the tip, and the inner space 41, the gas path 52, and the nozzle hole N1 of the inner nozzle 4 are all coaxial.

  The shielding plate 7 is attached to the step portion 51 of the nozzle cover 5 to seal the proximal end side opening of the inner nozzle 4, and is located on the inner space 41 of the inner nozzle 4 and the proximal end side of the laser welding nozzle 3. The cross jet space S (FIG. 1) is isolated. The shielding plate 7 is formed of a transparent member such as glass.

  In such a configuration, laser light emitted from a laser oscillator (not shown) and collected by the condenser lens passes through the shielding plate 7, the inner space 41 of the inner nozzle 4, and the through holes 42 a and 43 a, and passes through the top nozzle 6. The light is emitted from the nozzle hole N1. Further, the shield gas supplied from the shield gas supply device flows into the gas path 52 via the gas supply hole 53 while drawing a spiral as shown by an arrow G (FIG. 5), and the nozzle hole N1 of the top nozzle 6 And sprayed onto the welding member W. At this time, as described above, since the internal space 41 of the inner nozzle 4 is isolated from the cross jet space S by the shielding plate 7, it is possible to prevent the shield gas from being sucked into the cross jet airflow flowing through the cross jet space S. The shield gas can be reliably injected from the nozzle hole N1. Note that the cross jet air current is to prevent spatter and the like generated during welding from sticking to the condenser lens (or the protective lens located on the front end side of the condenser lens).

  Then, the laser welding head 1 is moved in the welding direction D1 (laser welding nozzle traveling direction; see FIG. 1) while emitting / injecting the laser beam and the shielding gas from the nozzle hole N1 in this way, so that in the welding member W Welding is performed. At this time, the laser welding head 1 is inclined by a predetermined angle θ (for example, 20 °) in the welding direction D1.

  Here, the oxidation of the welded portion occurs when the welded portion comes into contact with oxygen at a high temperature after welding. Therefore, the point of how to widen the shield range is a good prevention of oxidation. The shield range refers to a range in which external air containing oxygen is excluded by the shield gas. The wider the shield range (especially, the shield range on the rear side in the welding direction D1), the longer the blocking time from oxygen after welding, and the better the oxidation of the welded portion can be prevented. In addition, if the injection pressure of the shield gas is too high, the welded portion may lose its resistance against the injection pressure of the shield gas, and the surrounding air may be entrained and a sufficient shielding effect may not be obtained. The injection pressure from N1 is preferably lower.

  In this respect, in the present embodiment, since the tip portion of the nozzle hole N1 is expanded in a tapered shape, the shield gas injected from the nozzle hole N1 spreads around, and a wide shield range can be secured. Further, since the shield gas introduced from the gas supply hole 53 is supplied to the nozzle hole N1 via the annular gas path 52, the shield gas is rectified while passing through the gas path 52 and along the inner wall of the nozzle hole N1. It becomes easier to flow and spread around. Further, since the gas supply hole 53 is inclined in a direction approaching the central axis C2 of the gas path 52 as the central axis C1 approaches the tip, the supply of the shielding gas toward the nozzle hole N1 is performed smoothly. Can do. Further, since the central axis C1 of the gas supply hole 53 extends with an inclination with respect to the tangent line T of the outer peripheral surface 54 of the nozzle cover 5, unlike the case where it is perpendicular to the tangent line T, the shield gas is surrounded by the gas path 52. The shield gas that flows spirally along the direction and is injected from the nozzle hole N1 becomes easier to spread around.

  Further, since the central axis C2 of the laser welding head 1 (laser welding nozzle 3) is inclined in the welding direction D1, the shield gas is directed from the nozzle hole N1 to the rear side in the welding direction D1 (opposite to the welding direction D1). Thus, the shield range on the rear side in the welding direction D1 can be expanded. Further, since the shield gas supplied from the gas supply hole 53 is decelerated by once hitting the inner surface of the gas path 52 (the outer peripheral surface 43 of the inner nozzle 4), the injection pressure from the nozzle hole N1 can be lowered, Problems such as air entrainment can be avoided.

  In addition, by inclining the central axis C2 of the laser welding nozzle 3, spatter and the like that bounce off the welding member W during welding are less likely to enter the laser welding nozzle 3. Further, even if spatter enters the laser welding nozzle 3 through the nozzle hole N1, it can be blocked by the block members 42 and 43, and can be prevented from reaching the shielding plate 7. Can prevent contamination.

[Second Embodiment]
Next, a laser welding nozzle according to a second embodiment of the present invention will be described. This laser welding nozzle has substantially the same configuration as the laser welding nozzle according to the first embodiment described above, but differs in that the top nozzle is improved.

  More specifically, referring to FIGS. 7 and 8, the top nozzle 6A provided in the laser welding nozzle 3A according to the present embodiment has a plurality of auxiliary nozzle holes N2 in the vertical direction in the welding direction D1 rear side wall portion. Are arranged. These auxiliary nozzle holes N2 incline outward and extend toward the tip, and communicate the nozzle hole N1 with the outside. With such a configuration, a part of the shield gas supplied to the laser welding nozzle 3A is injected from the auxiliary nozzle hole N2, and the remaining part is injected from the nozzle hole N1 (the tip of the nozzle hole N1) in the same manner as described above. Is done. Thus, by injecting the shield gas from the auxiliary nozzle hole N2 in addition to the nozzle hole N1, the shield range on the rear side in the welding direction D1 can be further widened, and oxidation of the welded portion can be prevented more reliably.

[Third Embodiment]
Next, a laser welding nozzle according to a third embodiment of the present invention will be described. This laser welding nozzle has substantially the same configuration as the laser welding nozzle according to the first embodiment described above, but differs in that an auxiliary nozzle is attached to the top nozzle.

  More specifically, referring to FIG. 9, in the laser welding nozzle 3 </ b> B according to the present embodiment, the auxiliary nozzle 8 for injecting the shielding gas toward the rear of the welding direction D <b> 1 is provided on the outer surface of the top nozzle 6. It is attached. The auxiliary nozzle 8 is formed with a connection hole 81 to which a gas supply pipe (not shown) of the shield gas supply device is connected, and a plurality of auxiliary nozzle holes N3 are arranged in the vertical direction. The auxiliary nozzle hole N3 extends outwardly with inclination toward the tip. The shield gas supplied from the shield gas supply device to the auxiliary nozzle 8 is injected from the plurality of auxiliary nozzle holes N3 toward the welding member. Thus, by injecting the shield gas from the auxiliary nozzle hole N3 in addition to the nozzle hole N1, the shield range on the rear side in the welding direction D1 can be further widened, and oxidation of the welded portion can be prevented more reliably.

[Fourth Embodiment]
Next, a shield gas guide member according to a fourth embodiment of the present invention will be described. Referring to FIG. 10, here, a cylindrical side wall member (second welding member) W2 is placed on the upper surface of an annular flange member (first welding member) W1, and the flange member W1 and the side wall member W2 are placed. The case where laser welding is performed along the inner periphery of the side wall member W2 by the fillet joint will be described as an example.

  The shield gas guide member 9 of this embodiment includes a base member 10 and a flat plate-like pressing member 11. The base member 10 supports the flange member W1 from below, and its upper surface 10a is a flat surface. The base member 10 is formed with a plurality of gas paths 10b having openings on the upper surface 10a.

  The pressing member 11 is placed on the flange member W1 and has an outer shape corresponding to the cross section of the side wall member W2, and its outer diameter is set somewhat smaller than the inner diameter of the side wall member W2. . Therefore, when the pressing member 11 is placed on the flange portion W1 as required, a gap G1 is formed between the end surface of the pressing member 11 and the inner surface W2a of the side plate member W2.

  In addition, referring also to FIGS. 11 to 13, an annular first recess R <b> 1 is formed over the entire outer periphery of the lower surface of the pressing member 11, and the outer periphery of the first recess R <b> 1 extends over the entire periphery. A plurality of second recesses R2 are formed radially, and a protrusion P is defined between adjacent second recesses R2. The depth T1 of the first recess R1 is the same as the thickness T2 of the flange member W1. Therefore, when the pressing member 11 is placed on the flange member W1 so that the convex portion P is in contact with the upper surface of the flange member W1, the lower surface 11a of the pressing member 11 comes into surface contact with the upper surface 10a of the base member 10. The second recess R2 has an inner end R2a that is positioned on the inner side of the inner edge W1a of the flange member W1, and the opening of the gas path 10b is provided corresponding to the first recess R1 of the pressing member W1. It has been. Thus, the gas path 10b communicates with the gap G1 via the first recess R1 and the plurality of second recesses R2.

  For example, as shown in FIG. 14, such a pressing member 11 can be formed by laminating an upper plate 13 on a lower plate 12 in which a first recess R <b> 1 and a plurality of notches R <b> 3 are formed.

  Laser welding using the shield gas guide member 9 configured in this way is performed as follows. First, the flange member W <b> 1 is placed on the upper surface 10 a of the base member 10. Next, the side plate member W2 is placed on the upper surface of the flange member W1, and the pressing member 11 is placed on the flange member W1 so that a gap G1 is left between the side plate member W2. Then, as described above, the gas path 10b of the base member 10 communicates with the gap G1 via the first recess R1 and the plurality of second recesses R2. When shield gas is supplied from a shield gas supply device (not shown) to the gas path 10b of the base member 10, the shield gas flows into the gap G1 via the first recess R1 and the plurality of second recesses R2, and the flange member W1. It is supplied to a contact position with the side plate member W2, that is, a welding position. In such a state where the shield gas is supplied to the welding position, the laser beam is irradiated to the welding position to perform welding. The laser welding nozzle that irradiates the laser beam may be one that emits only the laser beam, or the laser welding nozzle 3 of each of the embodiments described above that injects a shield gas in addition to the laser beam. , 3A, 3B.

  As described above, when the shield gas guide member 9 in the present embodiment is used, laser welding can be performed while flowing the shield gas into the gap G1 provided between the pressing member 11 and the side plate member W2. (Welding member) Regardless of the shape and dimensions of W2, the shielding gas can be uniformly supplied to the welding position without unevenness, and as a result, oxidation of the welded portion can be reliably prevented.

  The laser welding head and the shield gas guide member according to the embodiment of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to such an embodiment and does not depart from the scope of the present invention. Various variations or modifications are possible.

  For example, in the laser welding nozzle 3 (3A, 3B) described above, a guide extending spirally may be provided in the gas path 52 and / or the nozzle hole N1 in order to make the shield gas flow more spirally. When providing a guide in the gas path 52, for example, as shown in FIG. 15, a spiral guide 90 may be provided on the outer peripheral surface 43 of the inner nozzle 4 that defines the gas path 52. At this time, a single guide 90 may be used, or a plurality of guides 90 may be used corresponding to each of the plurality of gas supply holes 53. Alternatively, instead of the outer peripheral surface of the inner nozzle 4, a spiral guide can be provided on the inner peripheral surface of the nozzle cover 5.

  Further, when a guide is provided in the nozzle hole N1, for example, as shown in FIG. 16, a spiral guide 91 may be provided on the inner peripheral surface of the top nozzle 6 (6A). At this time, it is important that the guide 91 does not interfere with the laser beam. Needless to say, the inclination direction of the guides 90 and 91 should be a direction along the spiral flow direction of the shield gas supplied from the gas supply hole 53.

  By providing the guides 90 and 91 in this way, the shield gas flowing through the gas path 52 and the nozzle hole N1 can flow more spirally along the guides 90 and 91 (that is, the circumferential direction of the laser welding nozzle). .

  Here, when a guide 91 is provided on the inner peripheral surface of the top nozzle 6 (6A) as shown in FIG. 16, the guide 91, like the block members 42 and 43 described above, reaches the shielding plate 7 of spatter. It will also serve as a blocking function.

  In the above-described fourth embodiment, the outer diameter of the lower plate 12 and the outer diameter of the upper plate 13 are the same, but the outer diameter of the lower plate 12 is slightly smaller than the outer diameter of the upper plate 13. The outer end of the projection P located between the adjacent second recesses R <b> 2 may have a small diameter and may be located somewhat inside the outer end of the upper plate 13. With such a configuration, the shield gas injected from the plurality of second recesses R2 spreads in the horizontal direction along the lower surface of the upper plate 13, and becomes easy to spread uniformly over the entire annular gap G1. The effect can be further improved.

DESCRIPTION OF SYMBOLS 1 Laser welding head 2 Head main body 3,3A, 3B Laser welding nozzle 4 Inner nozzle 5 Nozzle cover 6 Top nozzle 8 Auxiliary nozzle 9 Shield gas guide member 10 Base member 11 Holding member 41 Internal space 42, 43 Block member 52 Gas path 53 Gas supply holes 90, 91 Guide D1 Welding direction G1 Gap N1 Nozzle hole N2, N3 Auxiliary nozzle hole R1 First recess R2 Second recess

Claims (6)

A laser welding nozzle that performs welding by irradiating a welding member with laser light,
A cylindrical inner nozzle that allows laser light to pass through, a nozzle cover that covers the periphery of the inner nozzle, and a top nozzle that is attached to the tip of the nozzle cover,
Between the inner nozzle and the nozzle cover, an annular gas path through which shield gas passes is defined,
A nozzle hole is formed in the top nozzle,
Laser light is emitted from the nozzle hole of the top nozzle through the inner space of the inner nozzle,
Shield gas is injected from the nozzle hole of the top nozzle through the annular gas path,
The nozzle portion for laser welding, wherein the tip portion of the nozzle hole is formed in a tapered shape whose inner diameter gradually increases toward the tip. The nozzle cover is formed with a gas supply hole for supplying a shielding gas from the outside to the gas path,
The central axis of the gas supply hole is inclined in a direction approaching the central axis of the gas path toward the tip of the nozzle hole, and is inclined with respect to a tangent line of the outer peripheral surface of the nozzle cover. The nozzle for laser welding according to claim 1. Further comprising a shielding plate covering the proximal end side opening of the inner nozzle;
3. The laser welding according to claim 1, wherein a block member is disposed inside the inner nozzle, and a through hole for allowing the laser beam to pass through is formed in the block member. nozzle.   An auxiliary nozzle hole that communicates the nozzle hole with the outside is formed in a rear side wall portion of the top nozzle in the laser welding nozzle traveling direction, and a part of the shielding gas supplied to the nozzle hole is formed in the auxiliary nozzle hole. The nozzle for laser welding according to any one of claims 1 to 3, wherein the nozzle is sprayed backward from the nozzle in the direction of travel of the laser welding nozzle.   The laser welding according to any one of claims 1 to 3, wherein an auxiliary nozzle for injecting a shielding gas toward the rear in the laser welding nozzle traveling direction is attached to the outer surface of the top nozzle. Nozzle.   The laser welding nozzle according to claim 1, wherein a guide extending in a spiral shape is provided in at least one of the gas path and the nozzle hole.

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