JP2011251299A - Laser welding method and laser welding structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the burn-through of a member to be welded while reducing the weight of the member.SOLUTION: A laser beam L oscillated from a laser head 72 is irradiated to the rear surface of an abutting part 22C (rear surface 22B of a panel frame 22) along a slit 66 which is formed at a clamp board 62. By this, the abutting part 22C is heated and welded, and a part of an opening-side end 34A of a first rib 34 is heated and welded. After that, regions of the heat-welded abutting part 22C and the opening-side end 34A are cooled and integrally cured, and a welded part 46 (refer Fig.3 (not shown)) is formed. By this, the abutting part 22C and the opening-side end 34A of the first rib 34 are welded.

Description

  The present invention relates to a laser welding method and a laser welding structure.

  As a method of laser welding the two members, for example, as shown in FIG. 8A, a flange portion 102 is provided on the opening end portion 100A of the rib 100 having a C-shaped cross section, and the flange portion is superimposed on the panel 104. A method of irradiating the laser beam L to the laser beam 102 at a predetermined angle (for example, 90 degrees) is known. However, since the flange portion 102 is provided on the rib 100 in this method, the weight of the rib 100 increases. In addition, the circle shown with a dotted line in a figure is a welding part.

  On the other hand, as shown in FIG. 8B, the opening-side end portion 100A of the rib 100 is abutted against the panel 104, and a predetermined angle (for example, 45 degrees) is formed between the corners of the panel 104 and the opening-side end portion 100A. ) Is known to irradiate the laser beam L. In this method, since the flange part is not provided in the rib 100, the weight of the rib 100 is reduced. In addition, the circle shown with a dotted line in a figure is a welding part.

  However, as in the enlarged view shown in FIG. 8C, the region where the panel 104 and the opening side end portion 100A do not overlap in the irradiation region of the laser beam L irradiated to the corner (the two-dot chain line in the drawing). In A, a heat capacity becomes small compared with the area | region B where the panel 104 and the opening side edge part 100A overlap. Therefore, there exists a possibility that the area | region A may melt by welding heat.

  In view of the above-described facts, an object of the present invention is to obtain a laser welding method and a laser welding structure in which a member to be welded is suppressed from being melted while reducing the weight.

  The laser welding method according to claim 1 irradiates the abutting portion of the second plate member with the end surface of the first plate member abutted against the surface by irradiating a laser beam from the back side of the abutting portion, thereby The part and the first plate member are welded.

  According to the first aspect of the present invention, the abutting portion of the second plate material against which the end surface of the first plate material is abutted is irradiated with a laser beam from the back surface side of the abutting portion. Thereby, the abutting part and the first plate member are melt-bonded. Thus, since the conventional flange part 102 (refer FIG. 8 (A)) is not provided, the weight reduction of a 1st board | plate material can be achieved.

  Further, for example, by irradiating a laser beam perpendicularly or substantially perpendicularly to the back surface of the abutting portion, it is possible to irradiate only the portion where the first plate member and the second plate member overlap. Therefore, as compared with the conventional method (see FIG. 8B), the first plate material is burned off by the welding heat as compared with the method of irradiating the region 104 where the panel 104 and the opening side end portion 100A do not overlap with each other. Can be suppressed.

  A laser welding method according to a second aspect is the laser welding method according to the first aspect, wherein a plate thickness of the second plate member is made thinner than a plate thickness of the first plate member.

  According to the invention which concerns on Claim 2, the plate | board thickness of a 2nd board | plate material is thinner than the board | plate material of a 1st board | plate material. As described above, the present invention is particularly suitable when the thickness of the second plate is thin and the second plate is easily melted as compared with the first plate, and the laser is applied only to the portion where the first plate and the second plate overlap. By irradiating the beam, the first plate material can be prevented from being melted.

  The laser welding method according to claim 3 is the laser welding method according to claim 1 or 2, wherein the second plate member is attached to the first plate member by a first pressing plate superimposed on a back surface of the second plate member. The abutting portion is irradiated with a laser beam through a first slit formed in the first pressing plate while being pressed against the end face.

  According to the invention which concerns on Claim 3, the surface of a 2nd board | plate material and the end surface of a 1st board | plate material are distorted by press-contacting a 2nd board | plate material to the end surface of a 1st board | plate material with the 1st press plate piled up on the 2nd board | plate material. Even so, the end surface of the first plate member can be brought into close contact with the abutting portion without any gap. Therefore, poor welding is suppressed.

  The laser welding method according to claim 4 is the laser welding method according to claim 3, wherein the abutting portion different from the first slit is exposed after irradiating the abutting portion with the laser beam through the first slit. The first pressing plate is replaced with a second pressing plate in which a second slit is formed, and the second pressing plate is passed through the second slit while the second pressing member is pressed against the end surface of the first plate member. A laser beam is applied to the abutting portion.

  According to the invention which concerns on Claim 4, after irradiating a laser beam to the abutting part through the 1st slit of a 1st press plate, the said 1st press plate is substituted to a 2nd press plate. The second pressing plate is formed with a second slit that exposes an abutting portion different from the first slit, and the second slit is pressed against the end surface of the first plate by the second pressing plate. A laser beam is applied to the abutting portion through the projection.

  Here, for example, when there are a large number of abutting portions in the second plate material, if a large number of first slits are formed in the first pressure plate according to this, the rigidity of the first pressure plate decreases, and the first plate material The press-contact force of the second plate material with respect to the end face is reduced. On the other hand, in the present invention, by forming the first slit and the second slit that partially expose the abutting portion into the two first pressing plates and the second pressing plate, A decrease in the rigidity of the second pressing plate is suppressed. Accordingly, it is possible to suppress a decrease in the pressing force of the second plate material with respect to the end surface of the first plate material.

  The laser welding structure according to claim 5 includes: a first plate member; a second plate member whose end surface is abutted against the surface; and the second plate member where the end surface of the first plate member is abutted. The laser beam applied to the back surface of the abutting portion extends over the abutting portion and the first plate material, and includes a melting portion formed in the first plate material.

  According to the invention which concerns on Claim 5, the 1st board | plate material and the 2nd board | plate material are couple | bonded by the fusion | melting part formed ranging over the abutting part and 2nd board | plate material of a 2nd board | plate material. The melting part is formed in the first plate member by a laser beam irradiated from the back side of the abutting part. Here, by irradiating the back surface of the abutting portion with the laser beam vertically or substantially perpendicularly, it is possible to irradiate only the portion where the first plate material and the second plate material overlap. Therefore, as compared with the conventional method (see FIG. 8B), the first plate material is burned off by the welding heat as compared with the method of irradiating the region 104 where the panel 104 and the opening side end portion 100A do not overlap with each other. Can be suppressed. Moreover, since the conventional flange part 102 (refer FIG. 8 (A)) is not provided, the weight reduction of a 1st board | plate material can be achieved.

  A laser welding structure according to a sixth aspect is the laser welding structure according to the fifth aspect, wherein the second plate member is a panel frame constituting a vehicle seat back.

  According to the invention which concerns on Claim 6, a 1st board | plate material is welded to the panel frame which comprises a vehicle seat back by laser welding. Therefore, the weight reduction of the vehicle seat back can be achieved. Thereby, since the weight of the vehicle on which the vehicle seat back is mounted is reduced, fuel efficiency is improved, and the amount of carbon dioxide emission can be reduced.

  As described above, the laser welding method and the laser welding structure according to the present invention have an excellent effect that the welded member (first plate member) can be prevented from being melted while reducing the weight. ing.

1 is a perspective view showing a vehicle rear seat according to an embodiment of the present invention. It is a disassembled perspective view which shows the panel frame and X rib which concern on one Embodiment of this invention. It is a principal part expanded sectional view which shows the welding part of the panel frame and X rib which concern on one Embodiment of this invention. It is a perspective view which shows the panel frame, X rib, fixing jig, and clamp board which concern on one Embodiment of this invention. It is a principal part expansion perspective view of FIG. 4 which shows the fixing jig which concerns on one Embodiment of this invention. (A) And (B) is a top view which shows the clamp disk which concerns on one Embodiment of this invention, (C) is two clamp disks shown by FIG. 6 (A) and FIG. 6 (B) It is a top view which shows the state which piled up. It is sectional drawing which shows the state which welds the panel frame and X rib which concern on one Embodiment of this invention. (A) And (B) is sectional drawing which shows the conventional welding structure, (C) is a principal part expanded sectional view which shows the welding part of FIG. 8 (B).

  Hereinafter, a laser welding method and a laser welding structure according to an embodiment of the present invention will be described with reference to the drawings. Note that arrows X, Y, and Z shown in FIG. 1 respectively indicate the front and rear direction front side, the seat width direction outer side, and the seat height direction upper side of the vehicle rear seat to which the laser welding structure according to the present embodiment is applied. Yes.

  As shown in FIG. 1, a vehicle rear seat 10 to which the laser welding structure according to the present embodiment is applied includes a rear seat cushion 12 that supports the buttocks and thighs of a seated occupant, and the seat longitudinal direction of the rear seat cushion 12. A rear seat back (vehicle seat back) 14 is provided at the rear end and supports the back of the occupant, and a headrest 16 is provided at the upper end of the rear seat back 14 and supports the occupant's head. The rear seat cushion 12 is attached to the upper surface of a rear floor pan of a vehicle body (not shown). The rear seat back 14 constitutes one side of a so-called trunk-through left and right split-foldable rear seat back, and is a two-seat rear seat back. In FIG. 1, a single seat rear seat back (not shown) is arranged on the right side of the rear seat back 14.

  The rear seat back 14 includes a rear seat back frame 18 as a skeleton member. The rear seat back frame 18 supports a cushion material covered with a seat skin (not shown). The rear seat back frame 18 includes a panel frame 22 as a first plate member, and an X rib 24 that reinforces the panel frame 22.

  The panel frame 22 is a pressed part obtained by pressing a metal plate material (sheet metal or the like) into a thin-walled panel (about 0.6 mm in this embodiment). A pair of rotary hinges 26 that support the panel frame 22 so as to be rotatable in the front-rear direction of the seat are provided on both sides in the seat width direction at the lower end of the panel frame 22. Each rotary hinge 26 includes a hinge base 26A fixed to the upper surface of a rear floor pan of a vehicle body (not shown), and an L-shaped hinge arm 26B hinged to the hinge base 26A. The lower end portion of the panel frame 22 is overlapped with the hinge arm 26B, and the panel frame 22 is fixed to the hinge arm 26B with bolts and nuts (not shown). A plurality (four in this embodiment) of headrest support brackets 32 that support the headrest support 30 (see FIG. 1) of the headrest 16 are arranged in the seat width direction of the rear seat back 14 at the upper end of the panel frame 22. It is attached with.

  Note that through holes 28 (see FIG. 2) through which bolts for fixing the panel frame 22 to the hinge arm 26B are formed at both ends in the sheet width direction at the lower end of the panel frame 22.

  An X rib 24 is disposed on the front side of the panel frame 22 in the front-rear direction of the seat. The X rib 24 includes a first rib 34, a second rib 36, and a reinforcing cover 38 as a second plate material. The first rib 34 and the second rib 36 are thin-walled press parts (about 1.2 mm) formed by pressing a metal plate material (sheet metal or the like) into a C-shaped section (C-shaped section), and an opening having a section opened. It is arranged with the side facing the panel frame 22. The first ribs 34 and the second ribs 36 intersect each other at the center in the longitudinal direction, and are connected in a substantially X shape when viewed from the front side in the seat front-rear direction. Specifically, the central portion in the longitudinal direction of the second rib 36 is fitted into a notch groove formed in the central portion in the longitudinal direction of the first rib 34, and is joined by welding or the like. In addition, working holes 40 and 42 are formed at one end in the longitudinal direction of the first rib 34 and the second rib 36, and a panel frame is attached to the hinge arm 26B described above by a screwdriver or the like inserted into the working holes 40 and 42. A bolt (not shown) for fixing 22 can be tightened.

  Similar to the first rib 34 and the second rib 36, the reinforcing cover 38 is a thin-walled press part (about 1.2 mm) obtained by pressing a metal plate material (sheet metal, etc.) into a C-shaped section (C-shaped section). ing. The reinforcing cover 38 is stacked on the second rib 36 from the front side in the front-rear direction of the seat, and covers the connecting portion between the first rib 34 and the second rib 36. The connecting portion between the first rib 34 and the second rib 36 is reinforced by the reinforcing cover 38. The first rib 34 is fitted into a notch groove formed in the longitudinal center of the reinforcing cover 38 and joined by welding or the like.

  The X ribs 24 configured as described above have the end surfaces of the opening side end portions of the first ribs 34, the second ribs 36, and the reinforcing cover 38 on the surface 22A of the panel frame 22 (the front surface in the front-rear direction of the seat). It arrange | positions in the state contact | abutted and comprises the closed cross section with the panel frame 22. FIG. Moreover, the end surface of the opening side edge part of the 1st rib 34, the 2nd rib 36, and the reinforcement cover 38 is welded to the surface 22A of the panel frame 22 by the laser welding method which concerns on this embodiment.

  Here, as an example, a welded portion between the panel frame 22 and the opening-side end portion 34A of the first rib 34 is schematically shown in FIG. The panel frame 22 and the opening-side end portion 34A are arranged in a T shape with the end surface of the opening-side end portion 34A abutting against the surface 22A of the panel frame 22. A portion of the panel frame 22 where the end surface of the opening side end portion 34A is abutted (hereinafter referred to as “abutting portion 22C”) and the opening side end portion 34A are the abutting portion 22C and the opening side end portion 34A. Are connected by a melted portion 46 formed over the two. In the melting part 46, a part of the abutting part 22C and a part of the opening side end part 34A are heated and melted by the laser beam L (see FIG. 7) irradiated to the back surface (back surface 22B) of the abutting part 22C. Is solidified (solidified), and the melt width D in the cross section along the traveling direction of the laser beam L gradually decreases from the front side in the traveling direction of the laser beam L toward the far side in the traveling direction. ing. That is, the melting part 46 is formed as a result of the penetration depth H by laser welding reaching the opening side end part 34A beyond the abutting part 22C. Further, from the viewpoint of welding strength, the melting portion 46 is formed so as to fit within the opening side end portion 34A, that is, not to protrude from the opening side end portion 34A.

  Next, the laser welding method according to this embodiment will be described. Hereinafter, the laser welding method according to the present embodiment will be described focusing on the first rib 34 and the panel frame 22 constituting the X rib 24, and the second rib 36 and the reinforcing cover 38 to be welded by the same method. The laser welding method between the frame frame 22 and the panel frame 22 will be omitted as appropriate.

  As shown in FIG. 4, first, with the first rib 34, the second rib 36, and the reinforcing cover 38 constituting the X rib 24 facing upward, the X rib 24 is fixed to the fixing jig 50. Secure to. The fixing jig 50 includes a base 52, and the displacement of the first rib 34, the second rib 36, and the reinforcing cover 38 included in the X rib 24 in the horizontal direction is regulated at the base 52. A pair of regulating members 54 that project is projected.

  Here, FIG. 5 shows the first rib 34 disposed between the pair of regulating members 54. 5 is an enlarged view of a portion of the fixing jig 50 surrounded by a circle indicated by a dotted line in FIG. As shown in FIG. 5, the pair of restricting members 54 are disposed to face each other, and the first rib 34 is disposed between the restricting members 54 with the opening side thereof facing upward. Thereby, the displacement in the horizontal direction orthogonal to the longitudinal direction of the first rib 34 is regulated by the regulating member 54. A height adjusting member 56 is provided between the pair of regulating members 54, and the first rib 34 is placed on the height adjusting member 56. As a result, the opening side end portion 34 </ b> A is held in a state of slightly protruding from the upper end portion of the regulating member 54. Furthermore, high nuts (long nuts) 58 as pressure contact means are provided on both sides of the pair of regulating members 54 in the opposing direction. The high nut 58 has substantially the same height as the regulating member 54, and a bolt 60 described later can be tightened.

  Next, the panel frame 22 is placed on the X rib 24 fixed to the fixing jig 50, and the clamp plate (first pressing plate) 62 or the clamping plate (second pressing plate) is further mounted on the panel frame 22. ) Overlay 64. Here, the configuration of each clamp disk 62, 64 will be described in detail. A plurality of slits 66, 68 are formed in each clamp disk 62, 64, respectively. Each slit 66 and 68 is formed in the position corresponding to the abutting part of the panel frame 22 (refer FIG. 4), and as shown in FIG. 6 (A) and FIG. , 64 are overlaid on the panel frame 22, the different abutting portions of the panel frame 22 are exposed. Thereby, when the clamp plates 62 and 64 are replaced, the abutting portions of all the panel frames 22 to be welded are exposed. FIG. 6C shows a state in which the two clamping boards 62 and 64 are overlapped. Each clamp board 62, 64 is formed with a through hole 70 through which the bolt 60 passes.

  Among the clamp disks 62 and 64 configured as described above, first, the clamp disk 62 is overlaid on the panel frame 22, and the X rib 24 and the panel frame 22 are interposed between the clamp disk 62 and the fixing jig 50. The surface 22A of the panel frame 22 is pressed against the X rib 24. Specifically, as shown in FIG. 7, a bolt 60 as a pressure contact means is passed through a through hole 70 (see FIG. 6A) of the clamp board 62 and a through hole (not shown) formed in the panel frame 22. Then, the panel frame 22 and the first rib 34 are sandwiched between the clamp plate 62 and the regulating member 54 by tightening to the high nut 58 provided in the fixing jig 50. As a result, the surface 22A of the panel frame 22 is held in pressure contact with the end face of the opening-side end 34A of the first rib 34.

  The pressure contact means is not limited to the bolt 60 and the high nut 58, and various detachable connection means may be used, or an elastic body such as a spring that urges the clamp plate 62 toward the regulating member 54 is used. May be.

  Next, a laser head (laser oscillator) 72 provided on the back surface 22B side of the panel frame 22 is positioned at the abutting portion 22C of the panel frame 22, and the back surface (the back surface 22B) of the abutting portion 22C through the slit 66 of the clamp board 62. ) Is irradiated with a laser beam L. As shown in FIG. 3, the energy density of the laser beam L is adjusted so that the penetration depth H reaches the opening-side end portion 34A of the first rib 34 beyond the abutting portion 22C. Therefore, by irradiating the back surface of the abutting portion 22C with the laser beam L vertically or substantially perpendicularly, the abutting portion 22C is heated and melted, and a part of the opening-side end portion 34A of the first rib 34 is formed. It is heated and melted. Thereafter, the heated and melted portions of the abutting portion 22C and the opening-side end portion 34A are cooled and hardened integrally, and the melting portion 46 is formed. Thereby, a part of the abutting portion 22C to be welded and the opening side end portion 34A of the first rib 34 are welded.

In addition, from the viewpoint of ensuring the pressure contact force between the surface 22A of the panel frame 22 and the end surface of the opening-side end portion 34A of the first rib 34, the width of the slit 66 can be within a range in which the laser beam L does not interfere with the clamp plate 62. The smaller one is preferable. Further, the laser head 72 is positioned with respect to the abutting portion 22C of the panel frame 22 before the panel frame 22 and the clamp board 62 are placed on the X rib 24, laser type, optical type (camera) or ultrasonic type. Alternatively, the position of the opening-side end portion 34A of the first rib 34 may be detected in advance using a displacement sensor, and the laser head 72 may be positioned with respect to the abutting portion 22C based on the detection result. Furthermore, as the laser beam L used in the present embodiment, various laser beams such as a CO ₂ laser, a YAG laser, and a direct diode laser (DDL) can be used.

  Next, the clamp plate 62 is replaced with the clamp plate 64, and the surface 22A of the panel frame 22 is pressed against the end surface of the opening side end portion 34A of the first rib 34 in the same procedure as described above to form the clamp plate 64. A laser beam L is applied to the back surface of another abutting portion 22C (for example, the left abutting portion 22C in FIG. 7) along the slit 68 (see FIG. 6B). Thereby, the remaining portion of the abutting portion 22C of the panel frame 22 to be welded and the opening side end portion 34A of the first rib 34 are welded. In the present embodiment, the clamp plate 62 is attached first, and then the clamp plate 62 is replaced with the clamp plate 64, but the attachment of the clamp plates 62 and 64 is in no particular order.

  As described above, in the present embodiment, the conventional flange portion 102 (see FIG. 8A) is not required, and thus the weight of the first rib 34 can be reduced. Therefore, since the weight of the vehicle on which the vehicle rear seat 10 is mounted is reduced, the fuel efficiency is improved and the amount of carbon dioxide emission can be reduced.

  Further, by irradiating the back surface of the abutting portion 22C of the panel frame 22 with the laser beam L vertically or substantially perpendicularly, the laser is applied only to a portion where the abutting portion 22C and the opening side end portion 34A of the first rib 34 overlap. The beam L can be irradiated. Therefore, as compared with the conventional method (see FIG. 8B), the first plate material is burned off by the welding heat as compared with the method of irradiating the region 104 where the panel 104 and the opening side end portion 100A do not overlap with each other. Can be suppressed. In particular, the laser welding method according to the present embodiment is suitable when the panel frame 22 is thinner than the first rib 34 and the panel frame 22 is easily melted. Of course, the laser welding method according to the present embodiment can be applied even when the plate thickness of the panel frame 22 is thicker than the plate thickness of the first rib 34.

  Further, by irradiating the laser beam L only to a portion where the abutting portion 22C and the opening side end portion 34A of the first rib 34 overlap, the penetration depth H can be increased. That is, as compared with the conventional method (see FIG. 8B) in which the corners of the panel 104 and the opening-side end portion 100A are laser-welded (see FIG. 8B), a wide melting area of the abutting portion 22C and the opening-side end portion 34A is ensured. Therefore, the welding strength is improved, and in particular, the penetration depth can be increased by irradiating the central portion in the plate thickness direction of the opening-side end portion 34A. 8B), since the irradiation direction of the laser beam L is different on both sides of the rib 100 (the right side and the left side of the rib 100 in FIG. 8B), the angle change of the laser head occurs. On the other hand, in the present embodiment, the back surface of the abutting portion 22C is irradiated with the laser beam L, so the irradiation direction of the laser beam L is constant, and the angle of the laser head 72 is not required to be changed. Raise It is possible to improve the productivity.

  Further, the surface 22A of the panel frame 22 is pressed against the end surface of the opening-side end portion 34A of the first rib 34 by the fixing jig 50 and the clamp boards 62 and 64, so that the end surface of the opening-side end portion 34A and the panel frame 22 are pressed. Even if the surface 22A is distorted, the surface 22A of the panel frame 22 can be closely attached to the end surface of the opening-side end portion 34A without a gap. Therefore, poor welding is suppressed. Further, since the laser head 72 is provided on the back surface 22B side of the panel frame 22, the restriction member 54 (see FIG. 7) of the fixing jig 50 does not become an obstacle, and continuous welding is possible. In contrast, in the conventional method (see FIG. 8B) in which the corners of the panel 104 and the opening-side end portion 100A of the rib 100 are laser-welded (see FIG. 8B), the regulating member 54 according to the present embodiment is disposed on both sides of the rib 100. If provided, the restricting member 54 becomes an obstacle, and the corners of the panel 104 and the opening-side end portion 100A cannot be irradiated with the laser beam L. Therefore, continuous welding cannot be performed, and the efficiency is deteriorated.

  Further, the slits 66 and 68 for exposing the different abutting portions of the panel frame 22 are divided into two clamp plates 62 and 64, whereby all the slits are formed in one clamp plate 62 (or the clamp plate 64). Compared with the case where 66 and 68 are formed, the fall of the rigidity of each clamp board 62 and 64 is suppressed. Accordingly, it is possible to suppress a decrease in the pressure contact force of the surface 22A of the panel frame 22 with respect to the end surface of the opening-side end portion 34A of the first rib 34. In the above-described embodiment, the two clamp plates 62 and 64 are used. However, all the slits 66 and 68 may be formed in one clamp plate 62 (or the clamp plate 64). 68 may be divided into three or more clamping boards.

  Moreover, in the said embodiment, although the panel frame 22 and X rib 24 which were press-processed as an example to be welded member was demonstrated, it is applicable also to components other than a press part. Moreover, it is applicable not only to a metal material but also to a non-metal material such as resin, ceramic, glass, and rubber. Furthermore, in the above embodiment, as an example, the rear seat back frame 18 constituting the vehicle rear seat 10 has been described as an example. However, the laser welding method and the laser welding structure according to this embodiment are components for various uses (for example, It can be applied to front seat back frames, railways, architecture, electronic devices, etc.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect.

10 Vehicle Rear Seat 14 Rear Seat Back (Seat Back)
22 Panel frame (second plate)
22A Front surface 22B Back surface 22C Abutting portion 34 First rib (first plate material)
36 Second rib (first plate)
38 Reinforcement cover (first plate)
46 Melting part 62 Clamping board (first pressing plate)
64 Clamping board (second pressing plate)
66 slit (first slit)
68 slit (second slit)
L Laser beam

Claims (6)

  A laser for irradiating the abutting portion of the second plate whose surface is abutted against the end surface of the first plate material with a laser beam from the back side of the abutting portion to weld the abutting portion and the first plate material Welding method.   The laser welding method according to claim 1, wherein a plate thickness of the second plate member is thinner than a plate thickness of the first plate member.   The first pressing plate stacked on the back surface of the second plate member is pressed against the end surface of the first plate member while pressing the second plate member to the abutting portion through the first slit formed in the first pressing plate. The laser welding method according to claim 1 or 2, wherein the laser beam is irradiated.   After irradiating the abutting portion through the first slit with a laser beam, the first pressing plate is replaced with a second pressing plate formed with a second slit that exposes the abutting portion different from the first slit, 4. The laser welding method according to claim 3, wherein the abutting portion is irradiated with a laser beam through the second slit while the second pressing member is pressed against the end surface of the first plate with the second pressing plate. A first plate,
A second plate whose end surface is abutted against the surface;
The laser beam applied to the back surface of the abutting portion of the second plate material against which the end surface of the first plate material is abutted, straddles the abutting portion and the first plate material, and is formed in the first plate material. Melted part,
Laser welding structure comprising   The laser welding structure according to claim 5, wherein the second plate member is a panel frame constituting a vehicle seat back.

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