JP2010279965A - Laser welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser welding method capable of adequately preventing deterioration of welding quality caused by positional deviation of a laser irradiation position and reducing work delay and work cost caused by countermeasures against the positional deviation in laser welding of oppositely arranged welding members. <P>SOLUTION: The laser welding method includes: the steps (step 11-step 13) in which first and second welding members are arranged oppositely from a laser machining head side for irradiating laser to a welding part where the first and second welding parts are welded while being opposite to each other in such a way that a gap between the first welding member and the second welding member is made small; and an irradiation step (step 14) of irradiating the laser from the laser machining head to a direction for reducing the gap and reflecting the laser by inner wall surfaces of the first and second welding members facing each other so as to guide it to the welding part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser welding method.

  An overlapping laser welding method is known in which welding members arranged in an overlapping manner are welded together. In this type of laser welding method, generally, a welding portion is formed by irradiating a laser to a range including an overlapped surface of a welding member to ensure a predetermined welding strength.

  When the laser beam is irradiated with a positional deviation from the overlapping surface, it becomes difficult to ensure sufficient welding strength, resulting in a decrease in welding quality. Therefore, it is necessary to position the laser beam with high accuracy with respect to the overlapping surface and irradiate the laser beam.

  In the laser welding method described in Patent Document 1, a plurality of weld beads are formed adjacent to each other within a certain range including the overlapped surface, and the welding quality generated with the positional deviation of the laser irradiation position is improved. The decrease is prevented (see Patent Document 1).

JP-A-10-328860

  When a laser welding method for forming a plurality of weld beads is employed, it is possible to prevent a deterioration in welding quality caused by a displacement of the laser irradiation position.

  However, depending on the shape of the welding member to be welded, it is not possible to secure a sufficient welding area for forming a plurality of weld beads. It may be necessary to irradiate the laser with high accuracy positioning. In addition, since a plurality of weld beads are formed each time a welding operation is performed, there is a problem in that the operation cost is increased along with a delay in the operation of the welding operation.

  Therefore, the present invention suitably prevents the deterioration of the welding quality that may occur due to the positional deviation of the laser irradiation position during laser welding of the welding members arranged facing each other, and delays the work due to the positional deviation prevention measures. Another object of the present invention is to provide a laser welding method capable of reducing the operation cost.

  In the laser welding method of the present invention, the first and second welding members are directed from the side of the laser irradiation unit that irradiates the laser toward the side of the welding portion where the first and second welding members are welded to face each other. And a step of arranging the first and second welding members to face each other so as to reduce a gap between them. Furthermore, it has an irradiation step of irradiating the laser from the laser irradiation portion in a direction in which the gap is reduced and reflecting the laser by the inner wall surface where the first and second welding members face each other to guide the welding portion.

  According to the present invention, the laser irradiated toward the minute gap formed between the first welding member and the second welding member is reflected and guided by the inner wall surfaces of the first and second welding members. The first and second welding members can be irradiated to the welded portion facing each other. Therefore, the 1st and 2nd welding members arranged in the welding form equivalent to the lap welding can be suitably welded, and while preventing the deterioration of the welding quality that may occur due to the displacement of the laser irradiation position. Further, it is possible to reduce work delays and work costs associated with measures for preventing displacement of the laser irradiation position.

It is a figure which simplifies and shows a laser welding apparatus. It is a flowchart which shows the process of the laser welding method. 3A and 3B are perspective views for explaining a laser welding method. FIG. 4A is a perspective view for explaining a laser welding method, and FIG. 4B is an arrow view seen from the direction of arrow 4B in FIG. It is a figure for demonstrating the welding locus | trajectory of a laser, and is the arrow line view seen from the arrow 5A direction of FIG. 4 (A). 6A to 6C are perspective views for explaining a welding member according to a modification. 7A and 7B are diagrams for explaining a laser welding method according to an application example, in which FIG. 7A is a diagram illustrating a door panel for an automobile as a welding member, and FIG. 7B is a diagram illustrating FIG. It is sectional drawing which expands and shows the principal part of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  With reference to FIG. 1, in the embodiment, the laser welding method of the present invention is applied to welding of flat steel plates 31 and 32 arranged to face each other. For the welding operation, a known remote laser welding apparatus 10 used for welding a steel plate or the like is used.

  1 to 4, the laser welding method according to the embodiment will be outlined. A laser processing head 21 (corresponding to a laser irradiation unit) that irradiates the first welding member 31 and the second welding member 32 with a laser. The gap g between the first and second welding members 31, 32 is small from the side of the welding portion 41 toward the welded portion 41 where the first and second welding members 31, 32 are welded facing each other. The step (steps 11 to 13) arranged so as to face each other, the laser beam is irradiated from the laser processing head 21 in the direction in which the gap g becomes smaller, and the first and second welding members 31 and 32 face each other. An irradiation step (step 14) in which the laser beam is reflected by the wall surface 42 and guided to the welded portion 41. In the laser irradiation step (step 14), the laser is applied to the first welding member 31 so that the laser irradiation angle θ1 is smaller than the opening angle θ2 formed by the first and second welding members 31 and 32. (FIG. 4B). In the step of arranging the first and second welding members 31 and 32 (steps 11 to 13), the first and second welding members 31 and 32 are clamped in the first and second welding members 31 and 32. The gap g is formed by moving the first and second welding members 31 and 32 away from each other so as to widen the opening angle θ <b> 2 (FIGS. 3A and 3B).

  The welded part 41 in the description means a welded part where the first and second welding members 31 and 32 are welded to each other. In the embodiment, a certain range of the inner wall surface 42 located on the side where the gap g between the first and second welding members 31 and 32 becomes smaller (hereinafter referred to as “the tip end side s”) is defined. It is set to the welded part 41.

  Hereinafter, embodiments will be described in detail.

  Referring to FIG. 1, the laser welding apparatus 10 performs operations of a laser welding robot 11 that performs welding by irradiating a laser to the first and second welding members 31 and 32, and operations of each part of the laser welding apparatus 10. A control unit 12 for controlling, a laser oscillator 13 for oscillating a laser, a clamping means 14 for clamping the first and second welding members 31 and 32, and a through hole 43 formed in the first welding member 31. And a guide member 15 that applies a pressing force to the second welding member 32.

  The laser welding robot 11 includes a laser processing head 21 that irradiates the welding portion 41 with a laser transmitted from the laser oscillator 13, and a robot arm 22 that moves the laser processing head 21 to a predetermined position. ing. An optical fiber 23 is used for laser transmission from the laser oscillator 13 to the laser processing head 21. In each figure, the laser L irradiated from the laser processing head 21 is indicated by a broken line.

  The laser processing head 21 has a lens group 24 for focusing and irradiating the transmitted laser and a rotatable optical mirror 25. The laser transmitted from the optical fiber 23 into the laser processing head 21 passes through the lens group 24 and enters the optical mirror 25. The optical mirror 25 is rotated by a driving source (not shown) and scans the laser along an arbitrary angle with respect to the first and second welding members 31 and 32 and an arbitrary welding locus. It is also possible to adjust the focal position of the laser by the lens group 24 and to irradiate with the laser defocused.

  The robot arm 22 is a general multi-indirect robot arm. The laser processing head 21 arranged at the tip is moved in various directions according to the operation given by the teaching work.

  The control unit 12 controls the operation of each unit of the laser welding apparatus 10. For example, the laser irradiation with the set output energy, the laser scanning along the welding locus, the laser irradiation timing, and the like are adjusted.

  The clamp means 14 is provided so as to be movable forward and backward with respect to the first and second welding members 31 and 32 disposed on the mounting table 26. The first and second welding members 31 and 32 are sandwiched between the mounting table 26 and both the welding members 31 and 32 are clamped (FIG. 3A). The clamping means 14 is not limited to the illustrated configuration, and can be appropriately changed within a range having a function of pressing the first and second welding members 31 and 32.

  The guide member 15 is provided so as to be movable forward and backward with respect to the first and second welding members 31 and 32 as in the case of the clamping means 14. The guide member 15 moves forward with respect to the second welding member 32 from the first welding member 31 side, and applies a pressing force to the second welding member 32 (FIG. 3B). The guide member 15 is not limited to the illustrated configuration, and can be changed as appropriate.

  3A and 3B, in the welding operation, the first and second welding members 31 and 32 are arranged on the mounting table 26 with the inner wall surfaces 42 of the welding members 31 and 32 facing each other. To do. The welding means 31 and 32 are clamped by moving the clamping means 14 forward. In a clamped state, the guide member 15 is pressed against the second welding member 32 through the through hole 43 provided in the first welding member 31. In conjunction with this pressing, the clamping means 14 is moved backward to form an opening 44 for introducing a laser between the first and second welding members 31 and 32. The second welding member 32 gradually moves away from the first welding member 31 so as to widen the opening angle θ2 formed by the first and second welding members 31, 32, and from the opening 44 side to the tip portion. A gap g that gradually decreases in size toward the side s is formed.

  The welding part 41 is set to the inner wall surface 42 located in the back surface side of the site | part which clamped the 1st and 2nd welding members 31 and 32, for example. By reducing the dimension w1 of the gap g, it is possible to perform laser welding in a welding form equivalent to the overlap welding.

  The opening angle θ2, the dimension w2 of the opening 44, and the dimension w1 of the gap g can be arbitrarily formed by adjusting the pressing force of the guide member 15. For example, when the laser beam diameter is about 0.6 mm, the opening angle θ2 is 20 °, the dimension w2 of the opening 44 is 1.2 mm, and the dimension w1 of the gap g in the welded part 41 is about 0.3 mm. It is desirable to set.

  Referring to FIGS. 4A and 4B, the laser irradiation step is performed with the gap g formed. The laser is irradiated from the laser processing head 21 in a direction in which the dimension w1 of the gap g is reduced. Laser is incident on the welded portion 41 through the opening 44 and the gap g.

  In order to weld the welding members 31 and 32 more reliably, the laser passes through the center position of the gap g without being biased toward the first welding member 31 side or the second welding member 32 side. It is desirable to irradiate. Therefore, it is necessary to irradiate the laser with high precision positioning at the center position of the minute gap g. However, when laser irradiation is repeatedly performed, an accuracy error or the like due to the laser welding apparatus 10 occurs, and the laser may be irradiated with a deviation from the center position. If the laser irradiation position is greatly displaced and the laser is incident on a site far away from the welded portion 41, the welding quality may be deteriorated.

  Here, the inner wall surfaces 42 of the first and second welding members 31 and 32 arranged so that the dimension w1 of the gap g gradually decreases from the laser processing head 21 side toward the tip end side s. The reflected laser is reflected and guided to the tip side s (reflection of the laser is indicated by an arrow a in the figure). The reflected laser is then incident directly on the welded portion 41 by direct or direct reflection by the inner wall surface 42 a plurality of times. As described above, the inner wall surfaces 42 of the first and second welding members 31 and 32 exhibit a function of guiding the irradiated laser beam with the position shifted from the welding portion 41 to the tip portion side s. It is possible to more reliably perform laser incidence on the.

  When the laser irradiation angle θ1 with respect to the first and second welding members 31 and 32 increases, the heat absorption rate of the laser on the inner wall surface 42 increases, and the loss of heat generated each time the laser is reflected increases. In such a case, it becomes difficult to give the amount of heat necessary for welding to the welded portion 41 set on the tip side s. Therefore, the laser is directed to the direction in which the dimension w1 of the gap g decreases, and the first irradiation angle θ1 of the laser is smaller than the opening angle θ2 formed by the first and second welding members 31 and 32. Irradiation is applied to the welding member 31 or the second welding member 32. By irradiating the laser in a state where the laser irradiation angle θ1 with respect to the welding members 31 and 32 is regulated to be small, it is possible to suppress the loss of heat generated each time the laser is reflected, and to melt the welding members 31 and 32 It is possible to more reliably apply the amount of heat required for the welding portion 41.

  When the opening angle θ2 is set to about 20 °, the laser irradiation angle θ1 is preferably set to about 10 °. When the laser irradiation angle θ1 is set in this way, the laser absorption rate at the inner wall surface 42 can be suppressed to about 35%. The laser irradiation angle θ1 is determined by the opening angle θ2 formed by the first and second welding members 31, 32, but can be appropriately changed along with the dimension w2 of the opening 44 and the dimension w1 of the gap g. .

  The welded portion 41 set to the first and second welding members 31 and 32 is formed by making the surface roughness of the portion 45 to be the welded portion larger than the surface roughness of other portions of the inner wall surface 42.

  When the surface roughness of the inner wall surface 42 is reduced by mirror finishing or the like, the portion where the surface roughness is reduced is more likely to reflect the laser as compared with other portions, and the heat absorption rate of the laser is reduced. On the other hand, when the inner wall 42 is subjected to uneven processing and the like, and the surface roughness is increased, the portion where the surface roughness is increased is less likely to reflect the laser compared to other portions, and the amount of heat of the laser is reduced. Absorption rate is improved. Therefore, a portion 45 having a surface roughness larger than that of other portions of the inner wall surface 42 is formed on the inner wall surfaces 42 of the first and second welding members 31 and 32, and the portion is set as the welded portion 41. . Since it becomes easy for the laser to enter the welded portion 41, it is possible to accurately perform welding at the welded portion 41 set at an arbitrary position.

  When steel plates are used for the welding members 31 and 32, for example, the surface roughness Ra (surface roughness defined by JIS standard B0601) of the welded portion 41 is desirably set to about 0.8 to 50a. By adopting the above surface roughness, it becomes possible to improve the absorption rate of the heat quantity of the laser in the welded portion 41 by about 15% as compared with other portions. Note that, for example, sand blasting or sanding can be used for processing to increase the surface roughness.

  The absorption rate of the heat quantity of the laser is improved with an increase in the temperature of the welding members 31 and 32 itself. The absorptivity of up to about 80%. As described above, by setting the portion 45 with the increased surface roughness in the welded portion 41, an increase in the heat absorption rate of the laser by increasing the surface roughness and an increase in the temperature of the welding members 31 and 32 are accompanied. The improvement of the heat absorption rate of the laser can be exhibited synergistically, and the heat amount of the laser can be more efficiently applied to the welded portion 41.

  At the time of laser welding, the laser irradiated from the laser processing head 21 is irradiated after being defocused. When the laser is defocused and irradiated, the amount of heat per unit area of the laser beam diameter decreases, and compared to the case of irradiation without defocusing, it is possible to suppress the loss of the amount of laser heat that occurs during reflection. It becomes possible.

  As described above, the amount of heat of a laser decreases each time it is reflected. For example, in the case where the laser is irradiated to the periphery of the opening 44, a significant loss of heat of the laser occurs on the side of the opening 44, and a sufficient amount of heat is applied to the welded portion 41. It becomes difficult. Therefore, it is possible to apply the heat necessary for melting the welding members 31 and 32 more reliably to the welded portion 41 by defocusing and irradiating the laser. Although the amount of heat per unit area of the beam diameter of the laser is reduced, the laser finally converges and enters the welded portion 41, so that the amount of heat necessary for melting the welded portion 41 is ensured. be able to.

  In the laser irradiation step, laser irradiation is advanced along a continuous welding locus 46 that reciprocates between the first and second welding members 31 and 32 (FIG. 5).

  When the first and second welding members 31 and 32 are welded by forming continuous weld beads instead of spot welding, the first welding member 31 and the first welding member 31 are The laser is irradiated so as to go back and forth between the second welding members 32 (the progress of the laser is indicated by an arrow b in the figure). When the laser is irradiated along the welding locus 46 that reciprocates between the first and second welding members 31 and 32, the laser is applied to the first and second welding members 31 and 32 on the basis of the center position of the gap g. It will be averaged to the side and converge. Therefore, it is possible to prevent the laser from being incident on the welded portion 41 toward the first welding member 31 side or the second welding member 32 side. Further, the welding operation can be simplified as compared with the case where the laser is scanned in a state of being positioned with high accuracy toward the center position of the gap g.

  Next, the laser welding method will be described.

  Referring to FIG. 3A, first and second welding members 31 and 32 are arranged on mounting table 26 such that both inner wall surfaces 42 face each other. The tip side s is clamped by the clamping means 14.

  Referring to FIG. 3B, the guide member 15 is connected to the second welding member 32 through the through hole 43 provided in the first welding member 31 in a state where the first and second welding members 31 and 32 are clamped. Press. The clamp means 14 is moved backward in conjunction with the pressing, and an opening 44 for introducing a laser is formed between the first and second welding members 31 and 32.

  The second welding member 32 gradually moves away from the first welding member 31 so as to widen the opening angle θ2 formed by the first and second welding members 31 and 32. By this separation movement, a gap g gradually decreasing in size from the opening 44 side toward the tip end side s is formed between the first and second welding members 31 and 32. The dimensions are gradually increased toward the tip side s by a simple operation of relatively moving the first and second welding members 31 and 32 while clamping the first and second welding members 31 and 32. A small gap g can be formed.

  The inner wall surface 42 located on the back surface side of the portion where the first and second welding members 31 and 32 are clamped is set in the welding portion 41. The part where the welded portion 41 is formed is processed in advance so that the surface roughness is increased.

  The dimension w1 of the gap g is formed small, the first and second welding members 31 and 32 are arranged in a welding form equivalent to the overlap welding, and laser welding is performed.

  Referring to FIGS. 4A and 4B, the laser is irradiated with the gap g formed. The laser is directed from the laser processing head 21 in the direction in which the dimension w1 of the gap g is reduced, so that the laser irradiation angle θ1 is smaller than the opening angle θ2 formed by the first and second welding members 31 and 32. The first welding member 31 is irradiated.

  The inner wall surfaces 42 of the first and second welding members 31 and 32 reflect the irradiated laser and guide it to the tip side s. The reflected laser is incident on the welded portion 41 or gradually converges in a direction in which the dimension w1 of the gap g decreases while repeating the reflection by the inner wall surface a plurality of times.

  Here, when the welding members are overlap-welded, a plurality of weld beads are formed adjacent to each other within a predetermined range including the overlapping surface, and the welding strength is reduced due to the positional deviation of the laser irradiation position. Laser welding methods to prevent are known. By adopting such a laser welding method, it is possible to prevent a decrease in welding strength caused by a displacement of the laser irradiation position. However, in the case of laminating and welding thin plate-like welding members, a sufficient welding area for forming a plurality of weld beads cannot be secured. Therefore, it is necessary to irradiate the laser after positioning with high accuracy with respect to the overlapping surface. In addition, since a plurality of weld beads are formed each time a welding operation is performed, there is a problem in that the operation cost is increased along with a delay in the operation of the welding operation.

  On the other hand, in the present embodiment, the first and second welding members 31, the laser irradiated toward the minute gap g formed between the first and second welding members 31, 32 are provided. The laser beam can be guided and incident on the welded portion 41 formed on the tip end side s. Therefore, the 1st and 2nd welding members 31 and 32 arrange | positioned with the welding form equivalent to an overlap welding can be welded suitably. As a result, it is possible to prevent a deterioration in welding quality that may occur due to the positional deviation of the laser irradiation position, and to reduce work delays and work costs associated with measures for preventing the positional deviation of the laser irradiation position.

  In the laser irradiation step, the laser is irradiated with the laser irradiation angle θ1 smaller than the opening angle θ2 formed by the first and second welding members 31 and 32. The loss of heat generated each time the laser is reflected can be suppressed, and the heat necessary for melting the welding members 31 and 32 can be more reliably applied to the welded portion 41.

  Since the portion 45 having a large surface roughness is formed and the portion is set in the welded portion 41, the laser can be incident on the welded portion 41 more reliably. It becomes possible to accurately perform welding at the welding portion 41 set at an arbitrary position.

  The laser irradiated from the laser processing head 21 is irradiated after being defocused. When the laser is defocused and irradiated, the loss of heat generated each time the laser is reflected can be suppressed as compared with the case where the laser is irradiated without defocusing. Therefore, it becomes possible to more reliably apply the amount of heat necessary for melting the welding members 31 and 32 to the welded portion 41.

  Referring to FIG. 5, the laser irradiation is advanced along a continuous welding locus 46 that reciprocates between the first and second welding members 31 and 32. Based on the center position of the gap g, the laser is converged by averaging on the first and second welding members 31 and 32 side. For this reason, it is possible to prevent the laser from being biased toward the first welding member 31 side or the second welding member 32 side with respect to the welded portion 41, and to further improve the welding quality. . Compared with the case where the laser is scanned in a state of being positioned with high accuracy toward the center position of the gap g, the welding operation can be simplified.

  After scanning the laser along a predetermined welding locus 46, the welding operation is terminated.

  As described above, in the present embodiment, the first and second welding members 31 are irradiated with the laser irradiated toward the minute gap g formed between the first and second welding members 31 and 32. , 32 so that the laser beam can be guided and incident on the welded portion 41 formed on the tip side s. Therefore, the 1st and 2nd welding members 31 and 32 arrange | positioned with the welding form equivalent to an overlap welding can be welded suitably. As a result, it is possible to prevent a deterioration in welding quality that may occur due to the positional deviation of the laser irradiation position, and to reduce work delays and work costs associated with measures for preventing the positional deviation of the laser irradiation position.

  In the laser irradiation step, the laser is irradiated with the laser irradiation angle θ1 smaller than the opening angle θ2 formed by the first and second welding members 31 and 32. The loss of heat generated each time the laser is reflected can be suppressed, and the heat necessary for melting the first and second welding members 31 and 32 can be more reliably applied to the welded portion 41. It becomes possible.

  In the step of arranging the first and second welding members 31, 32, the second welding member is moved from the first welding member 31 so as to widen the opening angle θ2 formed by the first and second welding members 31, 32. The gap g is formed by moving away. The dimensions are gradually increased toward the tip side s by a simple operation of relatively moving the first and second welding members 31 and 32 while clamping the first and second welding members 31 and 32. A small gap g can be formed.

  Since the portion 45 having a large surface roughness is formed and the portion is set in the welded portion 41, the laser can be incident on the welded portion 41 more reliably. It becomes possible to accurately perform welding at the welding portion 41 set at an arbitrary position.

  The laser irradiated from the laser processing head 21 is irradiated after being defocused. When the laser is defocused and irradiated, it is possible to suppress the loss of heat generated each time the laser is reflected, compared to the case where the laser is irradiated without defocusing. Therefore, it becomes possible to more reliably apply the heat quantity necessary for melting the first and second welding members 31 and 32 to the welded portion 41.

  In the laser irradiation step, laser irradiation is advanced along a continuous welding locus 46 that reciprocates between the first and second welding members 31 and 32. Using the center position of the gap g as a reference, the laser can be converged by averaging the first and second welding members 31 and 32. For this reason, it is possible to prevent the laser from being biased toward the first welding member 31 side or the second welding member 32 side with respect to the welded portion 41, and to further improve the welding quality. . Compared with the case where the laser is scanned in a state of being positioned with high accuracy toward the center position of the gap g, the welding operation can be simplified.

  The embodiment described above can be modified as appropriate.

  In the embodiment, the first welding member 31 is irradiated with laser to start the welding operation, but the second welding member 32 is irradiated with laser to start the welding operation. Is also possible.

  The position where the first and second welding members 31 and 32 are clamped is not particularly limited, and can be appropriately changed according to the position where the welded portion 41 is formed. Examples of the method for forming the gap g include a method in which the second welding member 32 is elastically deformed by pressing the guide member 15 to form the gap g, and any of the first and second welding members 31 and 32 is used. It is possible to employ a method in which a gap g is formed by applying a pulling force to one of the two and moving them relatively apart.

  The part 45 with the increased surface roughness may be formed on at least one of the first and second welding members 31 and 32 in accordance with the part where the laser is desired to be incident. Moreover, the surface roughness of each part in the inner wall surface 42 can be changed as appropriate, and the surface roughness of the inner wall surface 42 is made smaller than that of other parts to form a part where the heat absorption rate of the laser is reduced. Is also possible. For example, in order to induce multiple reflection of the laser, it is conceivable to form a portion having a small surface roughness around the opening 44 or other portion where the laser is to be actively reflected.

  The material and shape of the welding member are not limited to those described in the embodiment, and can be changed as appropriate. In addition to laser welding that scans a laser along a continuous welding locus, the present invention can be applied to spot welding, for example.

(Modification)
With reference to FIGS. 6A to 6C, in the modification, laser welding is performed on the first and second welding members 31 and 32 in which the flat portion 51 connected to the welding portion 41 is formed. We are carrying out. Description of parts and welding methods similar to those of the above-described embodiment is partially omitted.

  Referring to FIG. 6A, a flat steel plate is used for the first welding member 31. On the other hand, the second welding member 32 is formed with a flat portion 51 and a bent portion 52 extending so as to form a predetermined opening angle θ2 from the flat portion 51 toward the laser processing head 21 side.

  The flat portion 51 of the first welding member 31 and the flat portion 51 of the second welding member 32 are arranged to face each other, and a gap g is formed between the first welding member 31 and the bent portion 52. A gap g having an arbitrary shape and an arbitrary dimension is formed between the first and second welding members 31 and 32 simply by abutting and arranging the first welding member 31 and the second welding member 32. Is possible. Therefore, the operation of forming the gap g can be further simplified.

  Referring to FIG. 6B, the illustrated second welding member 32 is disposed between the first welding member 31 and the flat surface portion 51 when facing the first welding member 31. A bag-shaped storage portion 53 is formed to form a gap g in the inner wall. A gap g having an arbitrary shape and an arbitrary dimension is formed between the first and second welding members 31 and 32 by a simple operation of placing the first welding member 31 and the second welding member 32 in contact with each other. Can be made.

  With reference to FIG. 6C, the illustrated second welding member 32 is formed with a bent portion 54 that is bent into a curved surface together with the flat portion 51. As with the other modifications described above, any shape between the first and second welding members 31 and 32 can be achieved by a simple operation of placing the first and second welding members 31 and 32 in contact with each other, and A gap g having an arbitrary dimension can be formed.

  As described above, the laser welding method according to the modification uses the first and second welding members 31 and 32 in which the flat portion 41 that is continuous with the welded portion 41 and contacts and faces each other is used. The work to form can be simplified more and the work efficiency required for welding work can be improved. As in the above-described embodiment, the first and second welding members 31 and 32 are preferably used by irradiating a laser toward the gap g formed between the first and second welding members 31 and 32. Can be welded to.

(Application example)
With reference to FIGS. 7A and 7B, in the application example, the laser welding method of the present invention is applied to temporary fixing of the second welding member 32 to the first welding member 31.

  An automotive door panel 61 is applied to the first welding member 31, and a fastening fastener 62 for attaching a screw member 63 to the automotive door panel 61 is applied to the second welding member 32. Yes. After welding the fastener 62 for fastening, the operation | work which laser welds the other welding member 64 is performed.

  A minute gap g is formed between the door panel 61 for automobile and the fastener 62 for fastening, and laser welding is performed in a welding form equivalent to overlap welding. In order to irradiate the laser with respect to the door panel 61 for the automobile, the laser processing head 21 is placed on the extension line of the welded portion 41 (on the extension line in the upper direction in the drawing), and the fastening tool 61 is fastened. Can be welded.

  The laser irradiated toward the gap g is reflected between the door panel 61 for the automobile and the fastener 62 for fastening, and converges and enters the welded portion 41. As a result, it is possible to temporarily fasten the fastener 62 for fastening to the door panel 61 for an automobile (FIG. 7B).

  After welding the fastener 62 for fastening, the operation | work which welds the other welding member 64 to the door panel 61 for motor vehicles is continued. Here, when the welding portion 41 for welding the other welding member 64 is arranged facing the laser processing head 21, the laser irradiation angle is changed to be in a relatively wide range. Lasers can be distributed and irradiated (FIG. 7A). Therefore, it is possible to start the welding operation without greatly changing the arrangement or posture of the laser processing head 21 in the welding operation of the other welding members 64.

  When welding the automotive door panel 61 and the fastening portion 62 for fastening, which are arranged in a welding form equivalent to the lap welding, and then performing welding at a plurality of other locations on the automotive door panel 61, it is continuous. Thus, the welding work can be performed, and the work efficiency of the welding work can be improved.

  In the application example, the screw member 63 is fastened to the fastener 62 for fastening after laser welding. The gap g formed with a minute dimension is further reduced by fastening of the screw member 63, so that the presence of the gap g does not cause a reduction in product quality. Further, since the fastener 62 for fastening is welded inside the door panel 61 for automobiles, the appearance of the door panel 61 for automobiles, which is a product, is improved even when the gap g remains. There is no problem of deteriorating.

10 Laser welding equipment,
11 Laser welding robot,
12 control unit,
13 Laser oscillator,
14 Clamping means,
15 guide members,
21 Laser processing head (laser irradiation part),
22 robot arm,
23 optical fiber,
24 lens groups,
25 Optical mirror,
26 mounting table,
31 1st welding member,
32 second welding member,
41 welds,
42 inner wall surface,
43 through hole,
44 opening,
45 Site with increased surface roughness,
46 Welding locus,
51 plane part,
52 bends,
53 storage section,
54 folded part,
61 Door panel for automobile (first welding member),
62 Fastening fastener (second welded member),
63 Screw member,
64 Other welding members,
g Clearance,
s The tip side,
w1 The size of the gap,
w2 Dimensions of the opening,
θ1 Laser irradiation angle,
θ2 Aperture angle.

Claims (7)

The first and second welding members are directed from the side of the laser irradiating part that irradiates a laser toward the side of the welding part where the first and second welding members are welded to face each other. A step of arranging them facing each other so as to reduce the gap between the welding members,
An irradiation step of irradiating the laser from the laser irradiation portion in a direction in which the gap is reduced and guiding the laser to the welding portion by reflecting the laser beam by an inner wall surface facing the first and second welding members. Laser welding method.   In the irradiation step, the first welding member or the second welding member is irradiated with a laser so that a laser irradiation angle is smaller than an opening angle formed by the first and second welding members. The laser welding method according to claim 1.   3. The laser welding method according to claim 1, wherein the first and second welding members have flat portions that are continuous with the welded portion and face each other and contact each other.   The step of arranging the first and second welding members includes the first and second welding members so as to widen an opening angle formed by the first and second welding members in a state where the first and second welding members are clamped. The laser welding method according to claim 1, wherein the gap is formed by moving the second welding members away from each other.   At least one of the first and second welding members is formed such that the surface roughness of the portion to be the welded portion is larger than the surface roughness of the other portion of the inner wall surface. Item 5. The laser welding method according to any one of Items 1 to 4.   The laser irradiation method according to claim 1, wherein the irradiation step is performed by defocusing and irradiating a laser from the laser irradiation unit.   The laser irradiation method according to any one of claims 1 to 6, wherein the irradiation step proceeds with laser irradiation along a continuous welding locus reciprocating between the first and second welding members.

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