JP2006000893A - Laser welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser welding method where, even in the case three sheet materials are piled and are subjected to laser welding, the two joining faces among the respective sheet materials can be securely welded under the almost similar conditions without increasing the capacity of a laser beam. <P>SOLUTION: At the time when an intermediate sheet 1, the side edges 4a, 4b and 2a, 2b in joining sheets 4, 2 respectively arranged on both the faces of the intermediate sheet 1 are subjected to laser welding by a three-sheet pile, width-changed parts 10 in which the shape of the side edges 4a, 4b and 2a, 2b arranged on both the faces of the intermediate sheet 1 is shifted in a projection plane are provided, and laser welding operations Lw1, Lw2 are performed between the respective different width-changed part and the intermediate sheet 1, thus each side edge can be made to a two-sheet pile at the laser welded part with the intermediate sheet 1. In this way, the two places between both the faces of the intermediate sheet 1 and the joining sheets can be securely welded under the almost similar conditions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser welding method in which three panel materials are laser-welded in an overlapping manner.

  In laser welding, laser beams are irradiated from above the stacked metal plates to weld the stacked metal plates (see, for example, Patent Document 1).

This laser welding is a method of joining by irradiating a laser beam mainly on a metal and locally melting and solidifying the metal.
JP 2000-176664 A (page 6, FIG. 1)

  However, in the conventional laser welding, two metal plates are overlapped and joined, but in some cases, three metal plates may be laser-welded.

  In laser welding of three metal plates in this way, if laser welding is attempted at the same time in the same manner as in the prior art, it is necessary to increase the capacity of the laser beam, which increases the cost and increases the cost of the three metal plates. There is a possibility that the two joint surfaces between the plates cannot be welded under the same conditions.

  Therefore, in the present invention, even when three plate members are stacked and laser-welded, the joining surfaces of both plate members are reliably welded to the intermediate plate member under substantially the same conditions without increasing the laser beam capacity. The present invention provides a laser welding method that can be performed.

  In the present invention, when laser welding the intermediate plate and two joining plates respectively arranged on both surfaces of the intermediate plate in a three-layered manner, the two joining plates arranged on both surfaces of the intermediate plate The main feature is that a welded portion is provided with a shape change portion in which the shapes are shifted from each other on the projection plane, and laser welding is performed between each different shape change portion and the intermediate plate.

  According to the laser welding method of the present invention, each joining plate arranged on both surfaces of the intermediate plate is welded to the intermediate plate by shifting the shape-changing portion formed on each of the joining plates, so that each joining plate becomes a shape-changing portion. Since the two laser welded portions with the intermediate plate overlap each other, the two joint surfaces between the both surfaces of the intermediate plate and the joint plate can be reliably welded under substantially the same conditions without increasing the laser beam capacity. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 4 show a first embodiment of a laser welding method according to the present invention, FIG. 1 is a perspective view showing the middle part of a vehicle body to which the present invention is applied, and FIG. FIG. 3 is a cross-sectional view of the main part of the vehicle body corresponding to line A, FIG. 3 is a cross-sectional view of the laser welded part, and FIG. 4 is a plan view of the laser welded part.

  As shown in FIG. 1, the laser welding method of the first embodiment is applied to a joint portion of a front side member 2 coupled to a front portion of a vehicle body of a floor panel 1, and is formed in a hat-shaped cross section that opens upward. The front side member 2 as one joining plate is coupled to the dash panel 3 as the intermediate plate and the lower surface of the floor panel 1 so as to form a closed cross section.

  Further, the upper surface of the dash panel 3 and the floor panel 1 is coupled with a stiffener member 4 as the other joining plate having a hat-shaped cross section that opens downward corresponding to the arrangement portion of the front side member 2. is there.

  A substantially triangular side inner member straddling the lower side of the front side member 2 and the lower surface of the floor panel 1 is provided at the inner side in the vehicle width direction (left and right direction in FIG. 1) of the front side member 2 at the front portion of the floor panel 1. 5 is combined.

  A side sill 6 is provided on the side edge of the floor panel 1 in the vehicle width direction, and a front pillar 7 rises from the front end of the side sill 6 in the vehicle body. As shown in FIG. 2, the front side member 2 has a pair of flanges 2a and 2b as side edges facing each other on both sides in the vehicle width direction, and the stiffener member 4 on both sides in the vehicle width direction. A pair of flanges 4a and 4b as side edges are arranged to face each other.

  The flanges 2a and 2b are brought into contact with the lower surface of the floor panel 1, and the flanges 4a and 4b are brought into contact with the upper surface of the floor panel 1 so as to overlap the flanges 2a and 2b. The portions 4a and 4b are welded to the floor panel 1 so as to be joined together.

  The side inner member 5 is spot-welded on the outer side in the vehicle width direction to the lower surface of the front side member 2 and spot-welded on the flange 5a on the inner side in the vehicle width direction to the lower surface of the floor panel 1. It is.

  Therefore, the flange 2b on the inner side in the vehicle width direction of the front side member 2 is covered by the side inner member 5, and it is not possible to weld the flange 2b directly to the floor panel 1 from below at the covered portion. It becomes possible.

  For this reason, the flanges 4a and 4b disposed on the upper surface of the floor panel 1 and the flanges 2a and 2b disposed on the lower surface of the floor panel 1 are laser-welded from the upper side of the floor panel 1.

  Here, in the present embodiment, when laser welding three panels overlapped by the flanges 4a, 4b, the floor panel 1, and the flanges 2a, 2b from above, as shown in FIG. 3, the flanges 2a, 2b and The flanges 4a and 4b are formed as shape changing portions, for example, width changing portions 10, whose shapes are shifted from each other on the projection plane, and laser welding is performed between the different width changing portions 10 and the floor panel 1. .

  As shown in FIG. 4, the width changing portion 10 has a width W1 of the flanges 4a and 4b arranged on the laser welding side, that is, the upper surface side of the floor panel 1, smaller than the width W2 of the other flanges 2a and 2b. Laser welding Lw1 is performed between the flanges 4a and 4b on the welding side and the floor panel 1, and the portion where the floor panel 1 and the other flanges 2a and 2b protrude from the flanges 4a and 4b is laser-welded. Lw2.

  Therefore, according to the laser welding method of the first embodiment, the flanges 4a and 4b and the flanges 2a and 2b arranged on both surfaces of the floor panel 1 have the width change portions 10 formed on the floor panel 1 respectively. Laser welding Lw1 and Lw2 can be performed with two linear laser lines on one side.

  For this reason, since the flanges 4a and 4b and the flanges 2a and 2b have a two-layer structure in the portions where the shapes thereof change, that is, the laser welding Lw1 and Lw2 with the floor panel 1 due to the different widths W1 and W2, the capacity of the laser beam is increased. The two joint surfaces between the flanges 4a and 4b and the floor panel 1 and between the flanges 2a and 2b and the floor panel 1 can be reliably welded under substantially the same conditions without increasing the height.

  Therefore, the welding strength between the flanges 2a, 2b and 4a, 4b and the floor panel 1 that are stacked three times can be ensured and reliably joined without increasing the cost of laser welding.

  5 and 6 show a second embodiment of the present invention, in which the same components as those in the first embodiment are denoted by the same reference numerals and redundant description is omitted, and FIG. Sectional drawing and FIG. 6 are top views of a laser welding part.

  In the laser welding method of the second embodiment, as shown in FIGS. 5 and 6, flanges 4a and 4b and flanges 2a and 2b in which side edge changing portions 11 as shape changing portions are arranged on both surfaces of the floor panel 1 are used. The side edges of each side edge are formed in a wave shape (sawtooth shape may be used) in which the peaks 4m, 2m and valleys 4v, 2v are alternately arranged, and the peaks 4m, 2m of each side edge and the floor panel are formed. 1 is laser-welded Lw3 with one linear laser beam on each side.

  Therefore, according to the laser welding method of the second embodiment, the crests 4m of the flanges 4a and 4b and the crests 2m of the flanges 2a and 2b are alternately arranged by the side edge changing portions 11, The peaks 4m and 2m are overlapped at the contact portion with the floor panel 1.

  For this reason, since the flanges 4a and 4b and the flanges 2a and 2b can be laser-welded Lw3 as a two-layer structure with respect to the floor panel 1 by the respective mountain portions 4m and 2m, the laser beam capacity is the same as in the first embodiment. The two joint surfaces between the flanges 4a and 4b and the flanges 2a and 2b and the floor panel 1 can be reliably welded under substantially the same conditions without increasing the height.

  Further, the flanges 4a, 4b and 2a, 2b can reduce stress concentration due to welding heat and suppress wavy deformation due to the presence of the valleys 4v, 2v, respectively.

  7 and 8 show a third embodiment of the present invention, in which the same components as those in the above-mentioned embodiments are denoted by the same reference numerals and the description thereof is omitted, and FIG. FIG. 8 and FIG. 8 are plan views of laser welding portions.

  As shown in FIGS. 7 and 8, the laser welding method according to the third embodiment is basically similar to the second embodiment, on the side edges of the flanges 4a and 4b and the flanges 2a and 2b. Side edge changing portions 11 formed in a wave shape (or sawtooth shape) in which 4 m and 2 m and valley portions 4 v and 2 v are alternately arranged are formed.

  In this embodiment, as shown in FIG. 8, the side edge changing portions 11 formed on the left and right flanges 4a and 4b and the flanges 2a and 2b facing each other in the vehicle width direction are formed asymmetrically.

  That is, a large number of crests 4m and 2m of the flanges 4a and 4b and the flanges 2a and 2b facing left and right (vehicle width direction) are formed in the length direction with a constant pitch P1, but in this embodiment, each crest 4m and 2m are asymmetrically shifted by a half pitch (P1 / 2) in the vehicle longitudinal direction (left-right direction in FIG. 8).

  Then, laser welding Lw3 is performed between the respective mountain portions 4m, 2m and the floor panel 1 in the state where the mountain portions 4m, 2m are shifted by a half pitch in the vehicle front-rear direction as described above. I am doing so.

  Therefore, according to the laser welding method of the third embodiment, the flanges 4a and 4b, the flanges 2a and 2b, and the floor panel 1 can be laser-welded Lw3 as a two-layer structure with the respective mountain portions 4m and 2m. In addition, by shifting the respective peak portions 4m and 2m in the vehicle front-rear direction, stress concentration on the flanges 4a and 4b and the flanges 2a and 2b can be reduced as in the second embodiment.

  FIGS. 9 and 10 show a fourth embodiment of the present invention, in which the same components as those of the above-described embodiments are denoted by the same reference numerals and redundant description is omitted, and FIG. 9 is a sectional view of a laser welded portion. FIG. 10 and FIG. 10 are plan views of laser welding portions.

  As shown in FIGS. 9 and 10, the laser welding method of the fourth embodiment is basically provided with a width changing portion 10 similarly to the first embodiment, and is arranged on the upper surface side of the floor panel 1. , 4b is formed to be narrower than the width W2 of the other flanges 2a, 2b.

  In this embodiment, as shown in FIG. 10, the two-layer overlap portion of the flanges 4a and 4b on the welding side and the floor panel 1, and the floor panel 1 and the other flanges 2a and 2b protrude from the flanges 4a and 4b. One laser beam is wave-shaped on each side so as to straddle the two overlapping portions with the portion to be laser welded Lw4.

  Therefore, according to the laser welding method of the fourth embodiment, even if welding is performed with the same laser capacity as in the first to third embodiments, the flanges 4a and 4b, the flanges 2a and 2b, and the floor panel 1 are three pieces. In the overlapped portion, the flanges 4a and 4b and the floor panel 1 are welded, and in the portion protruding from the flanges 4a and 4b of the flanges 2a and 2b, the flanges 2a and 2b and the floor panel 1 are welded, respectively. In addition, the laser welding Lw4 can be performed with one laser beam, and the laser beam of the laser welding Lw4 is made into a wave shape, so that the length of the welding Lw4 with respect to a predetermined length of the welded portion can be increased. Therefore, the welding strength can be increased.

  11 and 12 show a fifth embodiment of the present invention, in which the same components as those of the above-mentioned embodiments are denoted by the same reference numerals and redundant description is omitted, and FIG. 11 is a sectional view of a laser welded portion. FIG. 12 and FIG. 12 are plan views of laser welded portions.

  In the laser welding method of the fifth embodiment, as shown in FIGS. 11 and 12, a flange 4 a that is provided on the upper surface side of the floor panel 1, basically provided with a width changing portion 10 as in the first embodiment. , 4b is formed to have a width W1 narrower than the width W2 of the other flanges 2a, 2b, and one laser line is wave-shaped on each side as in the fourth embodiment. Laser welding Lw4.

  In this embodiment, as shown in FIG. 12, the left and right flanges 4 a and 4 b facing each other in the vehicle width direction and the waveform of the laser welding Lw 4 applied between the flanges 2 a and 2 b and the floor panel 1 are mutually interchanged on the left and right. As asymmetric.

  That is, the pair of laser welds Lw4 applied to the left and right are asymmetric by relatively shifting the pitch P2 of the corrugated portion by a half pitch (P2 / 2) in the vehicle longitudinal direction (left and right direction in FIG. 12).

  Therefore, according to the laser welding method of the fifth embodiment, since the corrugated portions of the laser welding Lw4 forming a pair applied in opposition to each other are asymmetric, the stress concentration acting on the corrugated portion of the laser welding Lw4 is reduced. Overall relaxation can be achieved.

  By the way, although the laser welding method of the present invention has been described by taking the first to fifth embodiments as examples, the present invention is not limited to these embodiments, and various other embodiments are employed without departing from the gist of the present invention. Of course, the intermediate plate and the joining plate are not limited to a metal such as a steel plate or an aluminum plate used in the vehicle body, and the present invention can be applied to all materials capable of laser welding.

It is a perspective view which shows the middle of the assembly | attachment of the vehicle body principal part to which this invention is applied. FIG. 2 is a cross-sectional view of the main part of the vehicle body corresponding to line AA in FIG. 1. It is sectional drawing of the laser welding part in 1st Embodiment of this invention. It is a top view of the laser welding part in 1st Embodiment of this invention. It is sectional drawing of the laser welding part in 2nd Embodiment of this invention. It is a top view of the laser welding part in 2nd Embodiment of this invention. It is sectional drawing of the laser welding part in 3rd Embodiment of this invention. It is a top view of the laser welding part in 3rd Embodiment of this invention. It is sectional drawing of the laser welding part in 4th Embodiment of this invention. It is a top view of the laser welding part in 4th Embodiment of this invention. It is sectional drawing of the laser welding part in 5th Embodiment of this invention. It is a top view of the laser welding part in 5th Embodiment of this invention.

Explanation of symbols

1 Floor panel (intermediate board)
2 Front side member (joint plate)
2a, 2b Flange (side edge)
2m Yamabe 2v Valley 4 Stuffer member (joint plate)
4a, 4b Flange (side edge)
4m Mountain part 4v Valley part 10 Width change part (shape change part)
11 Side edge change part (shape change part)
Lw1, Lw2, Lw3, Lw4 Laser welding

Claims (6)

When laser welding from one side by stacking three intermediate plates and two joining plates respectively arranged on both sides of the intermediate plate,
Provide welded portions of the two joining plates arranged on both sides of the intermediate plate with shape-changing portions whose shapes are shifted from each other on the projection plane, and perform laser welding between the different shape-changing portions and the intermediate plate. Laser welding method characterized by.   The shape change portion is a width change portion in which the overlap width of the side plate of the joint plate arranged on the laser welding side with respect to the intermediate plate is narrower than the overlap width of the side plate of the other joint plate with respect to the intermediate plate. 2. The laser welding method according to claim 1, wherein the joining plate and the intermediate plate are laser-welded, and the intermediate plate and the portion where the other joining plate protrudes from the welding-side joining plate are laser-welded.   The shape-changing part is a side where the side edges of the joining plate arranged on both sides of the intermediate plate are formed in a wave shape or sawtooth shape in which the crests of one side edge and the troughs of the other side edge are alternately arranged 2. The laser welding method according to claim 1, wherein the laser welding is performed between the peak portion of each side edge and the intermediate plate which is an edge changing portion.   4. The laser-welding method according to claim 3, wherein a pair of side edge changing portions of each joining plate are provided to be opposed to each other, and opposite side edge changing portions of each joining plate are formed asymmetrically. .   The laser welding method according to claim 2, wherein a laser beam that becomes a locus of laser welding is formed into a waveform.   6. The width change portions of each joining plate are provided in a pair and are opposed to each other, and laser welding waveforms applied to opposing side edge changing portions of each joining plate are made asymmetric to each other. Laser welding method.

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