JP5052242B2 - Laser welded joint and joined body using the joint - Google Patents

Description

  The present invention relates to a laser welded joint for butting the ends of extruded hollow members and joining them by laser welding or laser-arc hybrid welding, and a joined body having a vehicle structure assembled by the laser welded joint.

  In railway vehicles and the like, a vehicle structure made of a light aluminum alloy material is adopted to cope with the weight reduction of the vehicle body, and members are joined by laser welding or laser / arc hybrid welding. FIG. 4 is a longitudinal sectional view of an essential part of a panel welding structure in a railway vehicle disclosed in Patent Document 1 below. This is configured by a pair of honeycomb panels 101 in which an upper face plate 103 and a lower face plate 104 are previously joined to a joining member 102 by a brazing material 105. The joining members 102 are joined by laser welding at the upper and lower butted surfaces.

On the other hand, a laser welded joint as shown in FIG. 5 is disclosed in the following Patent Document 2, which is also joined by laser welding. Engagement projections 205 and engagement recesses 206 are formed, and the mating state of the joining end portions can be maintained by the fitting. Then, on the inner side of the welded projections 203 and 204 that are abutted with each other, back side spaces 107 and 108 are formed on the side opposite to the irradiation direction of the laser beam L. Therefore, at the time of joining, a laser beam is irradiated to the abutting portions of the welding projections 203 and 204, and a shielding gas is poured into the back space 107 and 108 to create a shielding gas atmosphere. As a result, oxidation in the backside spaces 107 and 108 is prevented, and a decrease in strength that prevents the oxide from being caught in the bead portion can be prevented.
JP-A-7-88643 JP-A-8-57670 JP 2007-125573 A

By the way, in the laser welded joint described in Patent Document 1, the space 110 in the joining members 102 and 102 that are abutted on each other is too large, and even if a shielding gas is introduced, the shielding environment is not stable. In addition, when a laser droplet is dropped when laser welding is performed on the upper side of the drawing, or when the laser beam penetrates, the joint on the opposite side is adversely affected.
On the other hand, backside spaces 107 and 108 are formed in the laser welded joint of Patent Document 2 and a shielding gas is supplied. However, when the shielding gas is directly supplied, if the pressure in the backside spaces 107 and 108 becomes high, the gas enters the melted part and causes blowholes.

  In that regard, Patent Document 3 discloses a welded joint of extruded hollow members 301 and 302 shown in FIG. 6 proposed by the present applicant. This is because a back side space consisting of a groove 315 formed on the projection 312 side is formed between the superimposed projections 311, 312, and the shield gas is the same as that of the laser beam L in the laser-arc hybrid welding performed on the groove 313. Sprayed from the direction, a shielding gas atmosphere is created in the space behind the groove 315. However, the back side space of the welded joint has a small volume and may increase the pressure. Also, since the joining position is at the end of the groove 315, the shield gas may not flow easily. Furthermore, since only one side of the joint portion is a projection 311, there is a concern that the heat distribution on the left and right sides of the aluminum having high thermal conductivity is uneven and the welding quality is deteriorated.

  Accordingly, an object of the present invention is to provide a laser welded joint having a stable shielding gas atmosphere and a good balance of heat conduction, and a joined body using the joint, in order to solve such problems.

The laser welded joint according to the present invention is connected by a plurality of inclined ribs in which an upper surface plate and a lower surface plate are arranged in the width direction, and an end rib at a width direction end perpendicular to the upper surface plate and the lower surface plate. was an extruded hollow profile, butt the extruded hollow profile together in the width direction, laser welding or laser is performed while spraying a shielding gas to the joint portion of the upper plate and between the lower surface plates are abutted thereof For arc hybrid welding, the pair of upper surface plates includes a pair of joint protrusions protruding from the end portions of both upper surface plates , and a sub-projection protruding from the end rib on one upper surface plate side. The pair of lower surface plates are formed with a pair of joint protrusions protruding from the end portions of both lower surface plates, and a sub-projection protruding from the end rib on one lower surface plate side, a pair of the upper plate the And when the butt the pair of lower plate together, the R plane, wherein the back side of the joint projection of the sub-projection upper plate tip formed by a curved surface other or lower surface plate and said end rib is continuous By abutting, a back side space surrounded by the pair of joining projections and sub-projections is formed.

In the laser welded joint according to the present invention, the pair of joining projections and the sub-projections have a back side space having a predetermined cross-sectional area in which an atmosphere is formed by a shielding gas that is injected from the same direction as the laser beam and enters the back side space. It is preferable that they are formed .

In the joined body according to the present invention, the upper surface plate and the lower surface plate are connected by a plurality of inclined ribs arranged in the width direction, and end ribs at the width direction end portions orthogonal to the upper surface plate and the lower surface plate. an extruded hollow shape member, with respect to the top plate and bottom plate laser-welded joint formed widthwise end portion of the, by laser welding or laser-arc hybrid welding is performed while spraying the shielding gas, the extrusion hollow shape The laser welded joint is formed by joining the pair of upper surface plates to the pair of upper surface plates, and a pair of joint protrusions protruding from the end portions of both upper surface plates. Sub-projections projecting from the end ribs are formed, and the pair of lower surface plates has a pair of joint projections projecting to the end portions of both lower surface plates, and projects from the end ribs to one of the lower surface plates. and the secondary projections are formed, If the serial abutted with each other pair of the upper plate and between the pair of lower face plate, the back-side of the junction protrusions sub projection upper plate or the lower plate of the tip formed by a curved surface other of said end ribs Is abutting against a continuous R surface to form a back side space surrounded by the pair of joint projections and sub projections.

  Therefore, according to the present invention, since the laser welding or the like is performed on the joint portion formed with the back side space surrounded by the pair of joint projections and the sub projections, the volume of the back side space can be freely set by the shape of the sub projections and the like. Both joint members can be set and a stable shield gas atmosphere can be created to effectively prevent the occurrence of blowholes and the laser beam is irradiated to the butted portion of the pair of joint protrusions. The balance of heat conduction is good and the welding quality can be made high.

Next, an embodiment of a laser welded joint according to the present invention and a joined body using the joint will be described below with reference to the drawings.
First, FIG. 3 is a perspective view showing a railway vehicle using the laser welded joint according to the present invention. The railway vehicle 80 is composed of a side structure 81 on the side surface, a roof structure 82 that forms a roof, a wife structure 83 that closes both ends in the longitudinal direction of the vehicle body, and a frame 84 that forms a floor surface. In particular, the side structure 81 and the roof structure 82 are joined by laser welding with the extruded hollow shape member 10 having a length (about 20 m) corresponding to the length of one vehicle body butted in the width direction.

Here, FIG. 1 is a view showing a laser welded joint for connecting the extruded hollow members 10 (10A, 10B) to each other. The extruded hollow members 10A and 10B are produced by extrusion molding using aluminum or an aluminum alloy in order to cope with the weight reduction of the vehicle body. Specifically, the upper surface plate 11 and the lower surface plate 12 are connected by a plurality of ribs 13 arranged in the width direction to form a cross-sectional shape having a truss structure. In addition, the direction which penetrates drawing is a vehicle body longitudinal direction, and the right and left of drawing are width directions. Such extruded hollow shape members 10A, 10B each other, joint widthwise end portion is fitted as shown, is joined by laser welding. Therefore, a set of laser welded joints is formed at the ends in the width direction of the extruded hollow shapes 10A and 10B.

The laser-welded joint made of a pair includes a right-end end rib 15 orthogonal to the upper surface plate 11 and the lower surface plate 12 so that one end is represented at the right end portion of the extruded hollow member 10A. A joining protrusion 17 is formed so as to protrude from the part rib 15 in the width direction. On the other hand, as shown in the left end portion of the extruded hollow member 10B, a left end end rib 16 orthogonal to the upper surface plate 11 and the lower surface plate 12 is formed, and the end rib 16 extends in the width direction. A joint projection 18 and a sub-projection 19 are formed so as to protrude. The sub-projections 19 are for forming a back space 20 that creates a shielding gas atmosphere on the back side of the joint where the joint projections 17 and 18 are abutted.

Here, FIG. 2 is an enlarged view of the joint portion of the laser weld joint on the top plate 11 side. The laser weld joint is formed in a symmetrical shape on the upper surface plate 11 side and the lower surface plate 12 side as shown in FIG.
The joining protrusions 17 and 18 are formed on the extension of the upper surface plate 11 and the lower surface plate 12, and are formed thick to ensure the joining strength. And in this embodiment, the joint protrusions 17 and 18 in which laser welding is performed are projected from the end ribs 15 and 16 together. That, extruded hollow shape members 10A, due to the high aluminum thermal conductivity constituting the 10B, in order to suppress the uneven heat dispersion of a joint, particularly in joining protrusion 18 side, the heat capacity of both left and right are configured to be the same ing.

The sub-projection 19 is inclined or curved from the base portion of the end rib 16 to the upper surface plate 11 side (or the lower surface plate 12 side), and the curved surface has an R surface 21 where the joint protrusion 17 and the end rib 15 are continuous. It is formed to hit the vicinity. This is constructed as extruded hollow shape member 10A, the mating of 10B is facilitated. That is, when the butted joining projections 17, 18 on both sides of the upper plate 11 and lower plate 12, the upper and lower sub-projection 19 is positioned in the vicinity of each of the R-plane 21, as shown in FIG. 1, extruded hollow profile 10A and 10B are easily fitted in the correct state.

By the way, if a shielding gas is directly supplied to the back side space 20 formed on the back side of the joint portion at the time of laser welding, when the pressure of the shield gas is high, the gas enters the melted joint portion and blowholes are easily generated. Therefore, in welding using the laser welded joint of the present embodiment, the shield gas is not directly supplied to the back space 20 formed by the sub-projections 19, but is only injected from the same direction as the laser beam L.

In that case, in order to make the shielding environment on the back side of the joint portion stable, it is necessary that the back side space 20 is formed with a predetermined volume. Because blowholes occur by too low Ri shielding gas pressure in the back space 20 is too high by the size of the volume. Therefore, in this embodiment, the cross-sectional area shown in FIG. 2 is formed to be 6 to 15 mm <2> based on the examination results so that the volume of the back space 20 becomes an appropriate value.

  Specifically, the protruding amount from the outer surface of the end ribs 15, 16 of the joining protrusions 17, 18 is formed between 0.5 and 3 mm, and the protruding amount from the outer surface of the end rib 16 of the sub-projection 19 is It is formed with 10 mm or less. Furthermore, the sub-projections 19 and the joint projections 18 are formed so that the distances between the opposing surfaces and the farthest position are 3 mm or less. Further, in order to stabilize the shielding environment of the back side space 20, even when the tip of the sub-projection 19 is separated from the end rib 15 side, the gap is formed to be 2 mm or less.

Next, in the railway vehicle 80, the extruded hollow shape member 10 (10A, 10B) having such a laser welded joint is abutted in the width direction, and the joint portion is joined by laser welding to form the side structure 81 and the roof structure 82. The When joining extruded hollow shape members 10A, the 10B, abutting surfaces of the joint projections 17, 18 is the junction 22. Therefore, as shown in FIG. 1, the laser beam L is irradiated to the joint portion 22 from the outside of the upper surface plate 11 and the lower surface plate 12 to the laser weld joint.

  Then, a shield gas is simultaneously blown onto the bonding portion 22 from the same direction as the laser beam L. Since the joining portion 22 becomes a joining line continuous in the longitudinal direction of the extruded hollow members 10A and 10B, in laser welding, the laser beam L is continuously irradiated along the joining line, and the shield gas is forward from the traveling direction. Be sprayed. In the joint portion 22 irradiated with the laser beam, the joint protrusions 17 and 18 are melted and welded by intensive heating. At that time, since a gap is formed in the irradiated portion of the laser beam L, the shield gas flows into the opposite side from there and a shield gas atmosphere is created in the back space 20.

  According to the laser welded joint of this embodiment, the back space 20 having a predetermined volume is formed, and a stable shielding gas atmosphere is created. Therefore, defects such as blow holes that can be generated by laser welding can be effectively prevented. it can. Therefore, it becomes possible to provide a railway vehicle made by high-quality laser welding. In the present embodiment, a shield gas atmosphere can be created by a simple configuration in which the sub-projections 19 are provided to form the back space 20, thereby improving the quality of the joint. Further, since the left and right sides of the joint portion 22 are the joint protrusions 17 and 18 having the same cross section, it is possible to suppress uneven heat dispersion, and even in the case of aluminum having high thermal conductivity, both the left and right heat capacities are made the same. It became possible to improve the welding quality.

Further, in the laser welded joint according to the present embodiment, the auxiliary projections 19 are formed on both sides of the upper surface plate 11 and the lower surface plate 12, and the ends of the extruded hollow members 10A and 10B are made to contact each other in the vicinity of the R surface 21. Therefore, the positioning in the thickness direction (vertical direction in the drawing) can be performed very easily. Furthermore, the presence of the sub-projections 19 prevents, for example, the influence of the droplets on the opposite lower surface plate 12 side by receiving the droplets generated by melting the bonding portion 22 during the bonding on the upper surface plate 11 side. I was able to do it. Even if the laser beam L may penetrate through the joint portion 22, it can be prevented from affecting the opposite welded portion by hitting the sub-projection 19.

  Since the end ribs 15 and 16 are formed in the extruded hollow member 10 (10A, 10B) provided with the laser welded joint according to the present embodiment, the upper surface plate 11 and the lower surface plate 12 are thin (2 to 3 mm). Even if it existed, the rigidity of the edge part of the width direction was able to be improved. Therefore, since the extruded hollow member 10 constituting the railway vehicle is a long member of about 20 m, the upper surface plate 11 and the lower surface plate 12 are deformed at the time of assembling the vehicle body, like those without the end ribs 15 and 16. There is no longer a risk of being lost. That is, handling of the extruded hollow shape member 10 became easy.

By the way, the laser weld joint of this embodiment is also effective in the case of a joining method by laser-arc hybrid welding. The laser-arc hybrid welding, mating extruded hollow shape member 10A, with respect to the junction 22 of 10B, with the irradiation of the laser beam L, the shielding gas is blown from the front of the traveling direction. Further, welding is performed by supplying a MIG arc, for example, by a MIG torch at the rear of the traveling direction. At this time, as in the case of the laser welding described above, the shield gas blown to the joint portion 22 enters the back space 20 to create a shield gas atmosphere. And there exists an effect similar to laser welding.

  As described above, the laser welded joint according to the present invention and the embodiment of the joined body using the joint have been described. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention. is there.

It is the figure which showed one Embodiment of the laser welding joint. It is the figure which expanded and showed the laser welding joint shown in FIG. It is a perspective view which shows the rail vehicle using a laser welding joint. It is a principal part longitudinal cross-sectional view of the panel welding structure in the rail vehicle disclosed by patent document 1. FIG. It is the figure which showed the conventional laser welding joint. It is the figure which showed the conventional laser welding joint.

Explanation of symbols

10 (10A, 10B) Extruded hollow profile 11 Upper surface plate 12 Lower surface plate 13 Ribs 15 and 16 End ribs 17 and 18 Joint projection 19 Sub projection 20 Back space

Claims (3)

An extruded hollow profile connected by a plurality of inclined ribs in which an upper surface plate and a lower surface plate are arranged in the width direction, and end ribs in a width direction end perpendicular to the upper surface plate and the lower surface plate, Laser welded joints for laser welding or laser-arc hybrid welding performed by abutting extruded hollow shapes in the width direction and injecting shield gas to the joined portions of the abutted upper and lower plates In
The pair of upper surface plates are formed with a pair of joint protrusions protruding from the end portions of both upper surface plates , and a sub-projection protruding from the end rib on one upper surface plate side ,
The pair of lower surface plates are formed with a pair of joint protrusions protruding from the end portions of both lower surface plates, and a sub-projection protruding from the end rib on one lower surface plate side,
When the pair of upper surface plates and the pair of lower surface plates are brought into contact with each other , the tip formed by the curved surface of the sub-projection is the other upper surface plate or the back surface of the joint protrusion of the lower surface plate and the end rib. A laser welded joint characterized by forming a back side space surrounded by the pair of joining projections and sub-projections by abutting against a continuous R surface . The laser weld joint according to claim 1,
The pair of joining projections and sub-projections are formed so as to form a back side space having a predetermined cross-sectional area that is jetted from the same direction as the laser beam and becomes an atmosphere by a shield gas that enters the back side space. Laser welded joint. An extruded hollow profile connected by a plurality of inclined ribs in which an upper surface plate and a lower surface plate are arranged in the width direction, and end ribs in the width direction end perpendicular to the upper surface plate and the lower surface plate, The extruded hollow shapes are joined to each other by laser welding or laser-arc hybrid welding performed while spraying a shielding gas to the laser welded joint formed at the width direction end of the top plate and bottom plate. In the joined body,
In the laser welded joint , the pair of upper surface plates are formed with a pair of joint protrusions protruding from the end portions of both upper surface plates , and a sub-projection protruding from the end rib on one upper surface plate side ,
The pair of lower surface plates are formed with a pair of joint protrusions protruding from the end portions of both lower surface plates, and a sub-projection protruding from the end rib on one lower surface plate side,
When the pair of upper surface plates and the pair of lower surface plates are brought into contact with each other , the tip formed by the curved surface of the sub-projection is the other upper surface plate or the back surface of the joint protrusion of the lower surface plate and the end rib. A bonded body characterized by forming a back side space surrounded by the pair of bonding projections and sub-projections by abutting against a continuous R surface .

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