WO2020217809A1 - Laser welding method and laser welding device - Google Patents

Abstract

A laser welding method comprising: a laser beam irradiation step for oscillating a laser beam and focusing the laser beam at a welding location; and a scanning step for scanning the spot of the laser beam. During laser welding, scanning is carried out continuously such that the spot moves outward while circling around a prescribed location, thereby forming a weld portion wherein a metal member has melted and which, in a planar view, is dot-shaped, and the input heat amount due to irradiation of the laser beam at the outer-circumferential portion of the weld portion is less than the input heat amount at an inner-circumferential portion, which is at least a partial region on the inner-circumferential side of the outer-circumferential portion.

Description

Laser welding method and laser welding equipment

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

Laser welding technology may be used to join metal members together. Joining of metal members by laser welding is performed by melting and solidifying a part of the metal members by irradiation with laser light. When metal members are joined by laser welding, they have the advantages of higher welding speed and less heat effect than when joining by resistance welding. Further, when metal members are joined to each other by laser welding, welding can be performed without contact with the metal members, the processing efficiency is high, and the rigidity can be increased by continuous welding.

For example, Patent Document 1 discloses a method of performing laser welding by executing two steps and joining two laminated plate materials with a gap between them. Specifically, in the method disclosed in Patent Document 1, first, the spot of the laser beam is scanned to melt the metal member in the first predetermined region. Next, the second predetermined region, which is the outer peripheral portion of the first predetermined region, is irradiated with laser light to melt the metal member in the region, and the molten metal is poured onto the welding marks in the first predetermined region.

In Patent Document 1, by performing welding by executing the two steps as described above, the depth of the recessed portion formed in the first predetermined region can be made shallow, and the wall thickness of the outer peripheral portion of the welded portion is thin. It is said that it is possible to suppress the deterioration of the welding strength.

Japanese Unexamined Patent Publication No. 2012-228717

However, the technique disclosed in Patent Document 1 has room for improvement from the viewpoint of work efficiency. Specifically, in the technique disclosed in Patent Document 1, the molten metal in the second predetermined region is poured onto the welding marks formed by melting and solidifying the metal member in the first predetermined region, so that the metal members in the second predetermined region are separated in time. It is necessary to perform two steps, which requires a long working time and is considered to reduce the working efficiency.

The present invention has been made to solve the above-mentioned problems, and even when there is a gap between the metal members, the bonding between the metal members with high bonding strength is high. It is an object of the present invention to provide a laser welding method and a laser welding apparatus capable of working efficiency.

The laser welding method according to one aspect of the present invention is a laser welding method in which a plurality of metal members are joined by laser welding, and the laser light is oscillated and the oscillated laser light is focused on a welded portion. A metal member is provided with an irradiation step and a scanning step for scanning the spot of the laser beam, and the spot of the laser beam is continuously scanned outward while orbiting around the predetermined location. A dot-shaped welded portion in a plan view is formed by melting the welded portion, and the amount of heat input by irradiation of the laser beam at the outer peripheral portion of the welded portion is at least a part region on the inner peripheral side of the outer peripheral portion. It should be lower than the amount of heat input in the peripheral part.

It is a schematic diagram which shows the schematic structure of the laser welding apparatus which concerns on 1st Embodiment. It is a schematic side view which shows the arrangement state of the plate material before welding. It is a schematic plan view for demonstrating the laser welding method using the laser welding apparatus which concerns on 1st Embodiment. It is a schematic cross-sectional view which shows the IV-IV line cross section of FIG. It is a schematic cross-sectional view which shows the part A of FIG. 4 enlarged. It is a schematic cross-sectional view which shows the structure of the outer peripheral part of the welded part at the time of performing welding by using the laser welding method which concerns on a comparative example. It is a schematic plan view for demonstrating the laser welding method which concerns on 2nd Embodiment. It is a schematic plan view for demonstrating the laser welding method which concerns on 3rd Embodiment. It is a schematic plan view for demonstrating the laser welding method which concerns on 4th Embodiment. It is a schematic diagram which shows the welding form which concerns on 5th Embodiment. It is a schematic diagram which shows the welding form which concerns on 6th Embodiment. It is a schematic diagram which shows the welding form which concerns on 7th Embodiment. It is a schematic diagram which shows the welding form which concerns on 8th Embodiment. It is a schematic diagram which shows the welding form which concerns on 9th Embodiment. It is a schematic diagram which shows the welding form which concerns on 10th Embodiment.

In the following, the embodiment will be described with reference to the drawings. The forms described below are examples of the present invention, and the present invention is not limited to the following forms except for its essential configuration.

[First Embodiment]
1. 1. Schematic configuration of the laser welding apparatus 1 The schematic configuration of the laser welding apparatus 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic view showing a schematic configuration of a laser welding apparatus 1 according to the present embodiment.

As shown in FIG. 1, the laser welding apparatus 1 according to the present embodiment includes a laser oscillator 10, an optical path 11, and a condensing unit (scanning unit) 12. The laser oscillator 10 oscillates the laser beam according to a command from the controller (control unit) 15 connected to the laser oscillator 10. The controller 15 includes a microprocessor composed of a CPU, ROM, RAM, and the like.

The laser beam oscillated by the laser oscillator 10 is propagated to the condensing unit 12 through the optical path 11. In the light collecting unit 12, the propagated laser light is focused (spots are formed) on the surface of the plate material (metal member) 501 in the plate material laminate 500. Then, the condensing unit 12 scans the spot of the laser beam on the surface of the plate member 501 according to the command from the controller 15.

In the present embodiment, an optical fiber cable is used as an example of the optical path 11, but in addition to this, various optical paths such as propagation by light reflection using a mirror can be adopted. Here, in the present embodiment, the plate material laminate 500 to be welded is a laminate of a plate material (metal member) 501 and a plate material (metal member) 502.

Further, the laser welding device 1 includes a welding robot 13 and a drive circuit unit 14 for driving the welding robot 13. The welding robot 13 has a light collecting unit 12 attached to its tip portion, and can move the light collecting unit 12 in three dimensions according to a command from the controller 15 connected to the drive circuit unit 14.

2. Schematic configuration of the plate material laminate 500 The schematic configuration of the plate material laminate 500 will be described with reference to FIG. FIG. 2 is a schematic side view showing an arrangement state of the plate materials 501 and 502 constituting the plate material laminate 500 before welding.

The plate material 501 and the plate material 502 are overlapped in the plate thickness direction (Z direction), but as shown in FIG. 2, there is a gap G of, for example, about 1 mm at the maximum between them before welding.

3. 3. Laser Welding Using Laser Welding Device 1 Laser welding using the laser welding device 1 according to the present embodiment will be described with reference to FIG. FIG. 3 is a schematic plan view for explaining a laser welding method using the laser welding apparatus 1.

As shown in FIG. 3, in the welding using the laser welding apparatus 1 according to the present embodiment, the controller 15 issues a command (command for executing the laser beam irradiation step) to oscillate the laser beam to the laser oscillator 10. Then, the condensing unit 12 is controlled so that the spot of the laser beam orbits around the orbiting center (predetermined location) Ax _LB1 . That is, the controller 15 controls the condensing unit 12 to scan the spot of the laser beam so as to execute the so-called laser screw welding in the welding of the plate material laminate 500 (execution command of the scanning step), and the welded portion. Welding and stirring of the plate members 501 and 502 in 100 are performed.

As shown in FIG. 3, in the present embodiment, the welded portion 100 which is substantially circular in plan view (when viewed from the direction perpendicular to the paper surface of FIG. 3) is formed. Then, the scanning of the spot of the laser beam is continuously performed from the circumference center Ax _LB1 side toward the outside of the welded portion 100. That is, in forming the welded portion 100, the spots of the laser beam are continuously scanned in time, instead of executing the two steps divided in time as in the technique disclosed in Patent Document 1.

Here, as shown in FIG. 3, when forming the welded portion 100, the controller 15 sets four regions Ar1 to Ar4 in the radial direction of the welded portion 100, and the laser light scanning locus LN ₁ is set for each of the regions Ar1 to Ar4. Irradiation of laser light is performed with a density (sparse and dense) of ~ LN ₄ . As a result, in the laser welding according to the present embodiment, the laser welding is performed so that the amount of heat input in the radial direction is different, and the welded portion 100 is formed.

Specifically, the density of the laser beam scanning locus LN ₄ in the fourth scanning region Ar4, which is the outer peripheral portion of the welded portion 100, is the density of the first scanning region (inner peripheral portion) Ar1 and the third scanning region (second annular portion). It is set lower (sparsely) than the densities of the laser light scanning trajectories LN ₁ and LN ₃ in Ar3. As a result, the irradiation density of the laser light in the fourth scanning region (outer peripheral portion) Ar4 is higher than the irradiation density of the laser light in the first scanning region (inner peripheral portion) Ar1 and the third scanning region (second annular portion) Ar3. The amount of heat input in the fourth scanning region Ar4 can be made lower than that in the first scanning region Ar1 and the third scanning region Ar3.

In the present embodiment, the laser beam scanning locus in the second scanning region (first annular portion) Ar2 set between the first scanning region Ar1 and the third scanning region Ar3 in the radial direction of the welded portion 100. The density of LN ₂ is set lower (sparsely) than the densities of the laser light scanning trajectories LN ₁ and LN ₃ in the first scanning region (inner peripheral portion) Ar1 and the third scanning region (second annular portion) Ar3. There is. As a result, in the laser welding according to the present embodiment, the irradiation density of the laser beam in the second scanning region (first annular portion) Ar2 is adjusted to the first scanning region (inner peripheral portion) Ar1 and the third scanning region (second annular portion). Part) It is lower (sparsely) than the irradiation density of the laser beam in Ar3, and the amount of heat input in the second scanning region (first annular portion) Ar2 is also the first scanning region (inner peripheral portion) Ar1 and the third scanning. The region (second annular portion) is lower than Ar3.

4. Form of Welded Part 100 The form of the welded part 100 formed by irradiating the laser beam as described with reference to FIG. 3 will be described with reference to FIGS. 4 to 6. FIG. 4 is a schematic cross-sectional view showing a cross section taken along line IV-IV of FIG. 3, and FIG. 5 is a schematic cross-sectional view showing an enlarged portion A of FIG. FIG. 6 is a schematic cross-sectional view showing the configuration of the outer peripheral portion of the welded portion when welding is performed by using the laser welding method according to the comparative example.

As shown in FIG. 4, the welded portion 100 formed by laser welding according to the present embodiment is formed in order from the circumferential center Ax _LB1 toward the outer side in the radial direction, and the first welding region 101 and the second welding region 102. It has a third welding region 103 and a fourth welding region 104. The first welding area 101 is in the first scanning area Ar1, the second welding area 102 is in the second scanning area Ar2, the third welding area 103 is in the third scanning area Ar3, and the fourth welding area 104 is in the fourth scanning area Ar4. , Each of which is formed in a corresponding area.

Then, in the welded portion 100, the gap G that was vacant before welding is filled with the molten and solidified metal member.

Next, as shown in FIG. 5, in the case of employing a laser welding method according to the present embodiment, the outer peripheral portion 104a of the radially outer portion of the weld 100, the thickness of the thickness T _A of the bridge portion is thin It is suppressed from being transformed. Further, the outer peripheral portion 104a is hard to be rapidly cooled by suppressing the thinning, and the fragile organization is also suppressed.

On the other hand, in Comparative Example that did not lower the heat input in the outer peripheral portion, as shown in FIG. 6, the thickness T _B of the bridge portion of the outer peripheral portion 900a of the weld 900 of the bridge section according to the embodiment it becomes thinner than the thickness T _A. Therefore, even if the plate thickness and the gap G of the plate materials 901 and 902 to be welded are the same as those in the present embodiment, the outer peripheral portion 900a is thinned, and the portion is rapidly cooled to cause a fragile structure in the portion. Will be formed.

The fourth welding region (outer peripheral portion) 104 of the welded portion 100 can be set to about 50% of the radius of the welded portion 100 at the maximum.

5. Effect In the laser welding method using the laser welding apparatus 1 according to the present embodiment, two plate members (metal members) 501 and 502 are joined by laser welding, so that the welding speed is higher than when resistance welding or the like is used. It is fast, has little heat effect, can be welded to the plate members 501 and 502 in a non-contact manner, has high processing efficiency, and can increase the rigidity by continuous welding.

Further, in the laser welding method using the laser welding apparatus 1 according to the present embodiment, the spot of the laser beam is orbited around the orbiting center Ax _LB1 to melt and stir the metal member of the portion. Since the welded portion 100 is formed, the molten metal will flow into the gap G even when there is a gap G between the plate members 501 and 502 in the state before welding. Therefore, in the case of the present embodiment, even if there is a gap G between the plate members 501 and 502 in the state before welding, the molten metal solidifies to fill the gap G, and gouge (underfill) or It is possible to suppress the occurrence of melting off.

Further, in the laser welding method using the laser welding apparatus 1 according to the present embodiment, in the formation of the welded portion 100, the amount of heat input in the fourth scanning region (outer peripheral portion) Ar4 is set to the first and third scanning regions (inner circumference). since we set lower than the heat input at the portion) Ar @ 1, Ar @ 3, fourth weld region (outer peripheral portion) 104 of the bridge thickness (wall thickness) T _a weld 100 that becomes thinner suppressed, thin Since quenching due to the formation can be avoided, it is possible to prevent the portion from becoming fragile and the residual stress from increasing.

Further, in the laser welding method using the laser welding apparatus 1 according to the present embodiment, in the formation of the welded portion 100, the spots of the laser beam are continuously scanned from the first scanning region Ar1 to the fourth scanning region (Ar4). Therefore, it is possible to suppress the lengthening of the working time as compared with the technique disclosed in Patent Document 1 above by executing two steps divided in time to suppress the thickness of the bridge portion from becoming thin. , It is possible to suppress a decrease in work efficiency.

Here, in the laser welding method using the laser welding apparatus 1 according to the present embodiment, one measure for reducing the amount of heat input in the fourth scanning region Ar4 to be lower than the amount of heat input in the first and third scanning regions Ar1 and Ar3. As a result, the density of the 4th laser light scanning locus LN ₄ in the 4th scanning region Ar4 is calculated from the densities of the 1st and 3rd laser light scanning loci LN ₁ and LN ₃ in the 1st and 3rd scanning regions Ar1 and Ar3. As a result, the irradiation density of the laser beam in the fourth scanning region Ar4 is made lower than that in the first and third scanning regions Ar1 and Ar3, and the amount of heat input is reduced. In the present embodiment in which such a method is adopted, the amount of heat input in the fourth scanning region Ar4 can be made lower than that in the first and third scanning regions Ar1 and Ar3 while maintaining the output of the laser beam constant. ..

Further, in the laser welding method using the laser welding apparatus 1 according to the present embodiment, when scanning the spot of the laser beam from the circumferential center Ax _LB1 toward the outer side in the radial direction, the first scanning region Ar1 and the third scanning region Ar3 , and set these areas Ar @ 1, density than the laser beam scanning locus _LN 1, LN ₃ at Ar3 is (was lower heat input) sparse second scanning region Ar2 between. Therefore, in the present embodiment, it is possible to suppress the input energy amount even when welding is performed in a wide range by adjusting the strength of the heat input amount on the inner peripheral side of the fourth scanning region Ar4.

As described above, in the laser welding apparatus 1 according to the present embodiment and the laser welding method using the laser welding apparatus 1, there is a gap G between the plate members (metal members) 501 and 502 in the state before welding. However, it is possible to join the plate members 501 and 502 with high joining strength with high work efficiency.

[Second Embodiment]
FIG. 7 is a schematic plan view for explaining the laser welding method according to the second embodiment.

As shown in FIG. 7, also in the laser welding method according to the present embodiment, the laser beam is applied to the surface of the plate material (metal member) 505 so as to orbit around the orbiting center (predetermined location) Ax _LB2. The spot is scanned and a laser beam is irradiated. As a result, the metal member of the portion irradiated with the laser beam is melted and agitated to form the welded portion 105 having a substantially circular shape in a plan view.

In the laser welding method according to the present embodiment, in scanning the spot of the laser beam, the scanning loci LN ₅ and LN are formed by the first scanning region Ar5 on the inner peripheral side in the radial direction and the second scanning region Ar6 on the outer peripheral portion side. There is a difference in the density of ₆ . That is, in the present embodiment, the second laser light scanning locus LN _{6 in} the second scanning region Ar ₆ corresponding to the outer peripheral portion is sparser than the first laser light scanning locus LN ₅ in the first scanning region Ar ₅ on the inner peripheral side. It is set to be.

Also in the laser welding method according to the present embodiment, the spot of the laser beam is scanned so as to be continuous from the first laser beam scanning locus LN ₅ to the second laser beam scanning locus LN ₆ .

Even with the laser welding method as described above, the welded portion 105 including the first welding region 106 corresponding to the first scanning region Ar5 and the second welding region 107 corresponding to the second scanning region Ar6 is formed. The laser welding method according to the present embodiment is different from the first embodiment in that the irradiation density of the laser beam is changed by dividing into two regions Ar5 and Ar6 in scanning the spot of the laser beam.

However, also in the laser welding apparatus according to the present embodiment and the laser welding method using the same, there is a gap G between the plate members (metal members) in the state before welding as in the first embodiment. Even in this case, it is possible to join the plate materials with high joining strength with high work efficiency.

[Third Embodiment]
FIG. 8A is a schematic plan view for explaining the laser welding method according to the third embodiment.

As shown in FIG. 8A, also in the laser welding method according to the present embodiment, with respect to the surface of one of the plate materials (metal members) to be welded, the circumferential center (predetermined location) Ax _LB3 is the center. The spot of the laser beam is scanned so as to go around and the laser beam is irradiated. As a result, the metal member of the portion irradiated with the laser beam is melted and agitated to form a welded portion 110 having a substantially rounded polygonal shape (in this embodiment, a rounded quadrangle as an example) in a plan view.

In the laser welding method according to the present embodiment, in scanning the spot of the laser beam, the density of the laser beam scanning locus is formed in the inner first scanning region Ar7 and the outer second scanning region Ar8 on the orbital center Ax _LB3 side. Is making a difference. Specifically, also in this embodiment, the laser light scanning locus in the second scanning region Ar8 corresponding to the outer peripheral portion is set to be sparser than the laser light scanning locus in the inner first scanning region Ar7. .. Here, as shown in FIG. 8A, in the present embodiment, both the first scanning region Ar7 and the second scanning region Ar8 are substantially rounded polygons in a plan view (in the present embodiment, as an example, a rounded quadrangle). It is set and is similar to each other.

Also in the laser welding method according to the present embodiment, the spot of the laser beam is scanned so as to be continuous from the laser beam scanning locus in the first scanning region Ar7 to the laser beam scanning locus in the second scanning region Ar8. ..

Even with the laser welding method as described above, the welded portion 110 including the first welding region 111 corresponding to the first scanning region Ar7 and the second welding region 112 corresponding to the second scanning region Ar8 is formed. The laser welding method according to the present embodiment is different from the first embodiment in that the plan view shapes of the first scanning region Ar7 and the second scanning region Ar8 are polygons with rounded corners.

However, also in the laser welding apparatus according to the present embodiment and the laser welding method using the same, there is a gap G between the plate members (metal members) in the state before welding as in the first embodiment. Even in this case, it is possible to join the plate materials with high joining strength with high work efficiency.

[Fourth Embodiment]
FIG. 8B is a schematic plan view for explaining the laser welding method according to the fourth embodiment.

As shown in FIG. 8B, also in the laser welding method according to the present embodiment, with respect to the surface of one of the plate materials (metal members) to be welded, the circumferential center (predetermined location) Ax _LB4 is the center. The spot of the laser beam is scanned so as to go around and the laser beam is irradiated. As a result, the metal member of the portion irradiated with the laser beam is melted and agitated to form the welded portion 115 having a substantially elliptical plan view.

In the laser welding method according to the present embodiment, in scanning the spot of the laser beam, the density of the scanning locus differs between the inner first scanning region Ar9 on the orbital center Ax _LB4 side and the outer second scanning region Ar10. Is on. Specifically, also in this embodiment, the laser light scanning locus in the second scanning region Ar10 corresponding to the outer peripheral portion is set to be sparser than the laser light scanning locus in the inner first scanning region Ar9. .. Here, as shown in FIG. 8B, in the present embodiment, both the first scanning region Ar9 and the second scanning region Ar10 are set to have a substantially elliptical shape in a plan view, and are similar to each other.

Also in the laser welding method according to the present embodiment, the spot of the laser beam is scanned so as to be continuous from the laser beam scanning locus of the first scanning region Ar9 to the laser beam scanning locus of the second scanning region Ar10.

Even with the laser welding method as described above, the welded portion 115 including the first welding region 116 corresponding to the first scanning region Ar9 and the second welding region 117 corresponding to the second scanning region Ar10 is formed. The laser welding method according to the present embodiment is different from the first embodiment in that the plan-view shapes of the first scanning region Ar9 and the second scanning region Ar10 are substantially elliptical.

However, also in the laser welding apparatus according to the present embodiment and the laser welding method using the same, there is a gap G between the plate members (metal members) in the state before welding as in the first embodiment. Even in this case, it is possible to join the plate materials with high joining strength with high work efficiency.

[Fifth Embodiment]
FIG. 9A is a schematic view showing a welding mode according to the fifth embodiment.

As shown in FIG. 9A, in the laser welding method according to the present embodiment, by performing laser welding, a screw portion 121 having a substantially circular shape in a plan view and a linear shape continuous with the screw portion 121 and extending in a plane line of sight in the X direction. A welded portion (nugget) 120 including a portion 122, a screw portion 123 which is continuous with the linear portion 122 and has a substantially circular shape in a plan view, is formed.

The screw portion 121 and the screw portion 123 are formed by the same method as the formation of the welded portion 100 according to the first embodiment. That is, the amount of heat input to the outer peripheral portions of the screw portions 121 and 123 is lower than that on the inner peripheral side region. Further, in the present embodiment, it is needless to say that the laser beam is continuously scanned at the time of forming each of the screw portions 121.123, and the laser to the linear portion 122 is formed before the metal member of the screw portion 121 solidifies. The light is continuously irradiated, and the screw portion 123 is continuously irradiated with the laser beam before the metal member of the linear portion 122 is solidified.

In the laser welding method according to the present embodiment, laser welding is performed by the above method, so that the same effect as that of the first embodiment can be obtained when forming the screw portions 121 and 123. Further, in the laser welding method according to the present embodiment, before the metal member of the screw portion 121 solidifies, the linear portion 122 is continuously irradiated with the laser beam, and the metal member of the linear portion 122 solidifies. Since the laser beam is continuously irradiated to the screw portion 123 before welding, even if there is a gap between the overlapped metal members in the state before welding, the screw portion 121 is formed and melted. The metal member flows into the gap between the members of the portion where the linear portion 122 is to be formed, and similarly, the metal member melted by the formation of the linear portion 122 is the portion where the screw portion 123 is to be formed. It flows between the members. Therefore, in the present embodiment, even when there is a gap between the metal members, it is possible to join with high strength.

[Sixth Embodiment]
FIG. 9B is a schematic view showing a welding mode according to the sixth embodiment.

As shown in FIG. 9B, in the laser welding method according to the present embodiment, by performing laser welding, a screw portion 126 having a substantially circular shape in a plan view and a linear portion 127 continuous with the screw portion 126 and extending in a plane line of sight , A welded portion (nugget) 125 composed of a screw portion 128 which is continuous with the linear portion 127 and has a substantially circular shape in a plan view is formed.

The screw portion 126 and the screw portion 128 are formed by the same method as the formation of the welded portion 100 according to the first embodiment. Further, also in the laser welding method according to the present embodiment, as in the fifth embodiment, when the welded portion 125 is formed, the laser beam is emitted to the linear portion 127 before the metal member of the screw portion 126 solidifies. The irradiation is continuously performed, and the screw portion 128 is continuously irradiated with the laser beam before the metal member of the linear portion 127 is solidified.

As shown in FIG. 9B, the linear portion 127 of the welded portion 125 according to the present embodiment is different from the fifth embodiment in the connection points with respect to the screw portion 126 and the screw portion 128. That is, in the welded portion 125 according to the present embodiment, the linear portion 127 is connected so as to form a tangent line at one radial end portion (outer edge portion in the Y direction) of each of the screw portion 126 and the screw portion 128. ing.

In the laser welding apparatus according to the present embodiment and the welding method using the laser welding apparatus, the form of the welded portion 125 is different from that of the fifth embodiment, but the same effect as that of the fifth embodiment can be obtained.

[7th Embodiment]
FIG. 9C is a schematic view showing a welding mode according to the seventh embodiment.

As shown in FIG. 9C, in the laser welding apparatus according to the present embodiment, by performing laser welding, a screw portion 131 having a substantially circular shape in a plan view and a linear portion 132 continuous with the screw portion 131 and extending in a plane line of sight , A screw portion 133 that is continuous with the linear portion 132 and is substantially circular in a plan view, a linear portion 134 that is continuous with the screw portion 133 and extends in a plane line of sight, and a screw portion 135 that is continuous with the linear portion 134 and is substantially circular in a plan view. And the welded portion (nugget) 130 including. Note that FIG. 9C shows an example of forming a welded portion 130 composed of three screw portions 131, 133, 135 and two linear portions 132, 134, but the screw portion and the linear portion are further continuous. Of course, it is also possible to form a screw.

The forming of each screw portion 131, 133, 135 is performed by the same method as the formation of the welded portion 100 according to the first embodiment. Further, also in the laser welding method according to the present embodiment, the linear portion 132 is irradiated with the laser beam before the metal of the screw portion 131 is solidified, and the laser is applied to the linear portion 134 before the metal of the screw portion 133 is solidified. Irradiate with light.

As shown in FIG. 9C, in the welded portion 130 according to the present embodiment, the number of screw portions 131, 133, 135 and the number of linear portions 132, 134 constituting the welded portion 130 are the same as those in the fifth embodiment and the above. It is different from the sixth embodiment.

In the laser welding apparatus according to the present embodiment and the welding method using the laser welding apparatus, the form of the welded portion 130 is different from the fifth embodiment and the sixth embodiment, but the fifth embodiment and the sixth embodiment are different. The same effect as that can be obtained. Further, in the present embodiment, the welding speed is increased by forming the welded portion 130 including more screw portions 131, 133, 135 and linear portions 132, 134 than in the fifth embodiment and the sixth embodiment. It is possible to secure higher joint strength while increasing the speed.

[8th Embodiment]
FIG. 10A is a schematic view showing a welding mode according to the eighth embodiment.

As shown in FIG. 10A, in the laser welding apparatus according to the present embodiment, by performing laser welding, a screw portion 141 having a substantially circular shape in a plan view and a linear portion 142 continuous with the screw portion 141 and extending in a plane line of sight , To form a welded portion (nugget) 140 composed of.

The screw portion 141 is formed by the same method as the formation of the welded portion 100 according to the first embodiment. Further, also in the laser welding method according to the present embodiment, as in the case of the fifth to seventh embodiments, when the welded portion 140 is formed, the linear portion is formed before the metal member of the screw portion 141 solidifies. Irradiation of the laser beam to 142 is continuously performed.

In the laser welding apparatus according to the present embodiment and the welding method using the laser welding apparatus, the form of the welded portion 140 is different from the fifth embodiment to the seventh embodiment, but the same effect as that of the fifth embodiment and the like is obtained. Obtainable.

[9th Embodiment]
FIG. 10B is a schematic view showing a welding mode according to the ninth embodiment.

As shown in FIG. 10B, in the laser welding apparatus according to the present embodiment, by performing laser welding, a screw portion 146 having a substantially circular shape in a plan view and a linear portion 147 continuous with the screw portion 146 and extending in a plane line of sight , To form a welded portion (nugget) 145.

In the laser welding method according to the present embodiment, the connection portion of the linear portion 147 of the welded portion 145 to the screw portion 146 is different from that of the eighth embodiment, and one end portion (Y direction) in the radial direction of the screw portion 146 is provided. It is connected so as to extend in the tangential direction at the outer edge).

The screw portion 146 is formed by the same method as the formation of the welded portion 100 according to the first embodiment. Further, also in the laser welding method according to the present embodiment, as in the case of the fifth to eighth embodiments, when the welded portion 145 is formed, the linear portion is formed before the metal member of the screw portion 146 solidifies. Irradiation of the laser beam to the 147 is continuously performed.

In the laser welding apparatus according to the present embodiment and the welding method using the laser welding apparatus, the form of the welded portion 145 is different from that of the eighth embodiment, but the same effect as that of the eighth embodiment can be obtained.

[10th Embodiment]
FIG. 10C is a schematic view showing a welding mode according to the tenth embodiment.

As shown in FIG. 10C, in the laser welding apparatus according to the present embodiment, the screw portion 152 having a substantially circular shape in a plan view is separated from the screw portion 152 toward one side in the radial direction of the screw portion 152 by laser welding. a flat sight line shape of the line portion 151 as extending (as indicated by the arrow B ₂₎ is, (as indicated by arrow B ₁₎ to be separated toward the screw portion 152 on the other side of the radially extending plane A line-of-sight linear portion 153 and a welded portion 150 composed of the linear portion 153 are formed.

The screw portion 152 is formed by the same method as the formation of the welded portion 100 according to the first embodiment. Further, in the present embodiment, both the start of the laser welding at the linear portion 151 and the start of the laser welding at the linear portion 153 are performed before the molten metal of the screw portion 152 solidifies.

In the laser welding apparatus according to the present embodiment and the welding method using the laser welding apparatus, the eighth embodiment and the ninth embodiment are described in that two linear portions 151 and 153 extending so as to be separated from the screw portion 152 are formed. Although it is different from the embodiment, the same effect as that of the eighth embodiment can be obtained.

[Modification example]
In the first to tenth embodiments, the condensing unit 12 is controlled to scan the spot of the laser beam, but the present invention is not limited to this. For example, the laser beam spot may be scanned by driving and controlling the tip portion of the welding robot 13, or the laser beam spot may be scanned using an XY table or the like. Further, in the first to tenth embodiments, the condensing unit 12 is controlled to move the spot of the laser beam, but the present invention is not limited to this. For example, the metal member to be welded may be moved to scan the spot of the laser beam.

Further, in the first to tenth embodiments, the two metal members are joined to each other, but the present invention is not limited to this. For example, if the present invention is applied to join three or more metal members, the same effect as described above can be obtained.

Further, in the first to tenth embodiments, the amount of heat input is different depending on the density of the laser beam scanning locus, but the present invention is not limited to this. For example, the amount of heat input may be changed by controlling the output of the laser beam, or the amount of heat input may be changed by controlling the pulse width. Further, the irradiation density of the laser light per unit area may be changed by blurring the focus while keeping the output of the laser light constant. Further, by making the scanning speed of the spot of the laser beam faster in the outer peripheral portion of the welded portion than in other regions, it is possible to reduce the amount of heat input in the outer peripheral portion.

Further, in the present invention, it is also possible to apply the above-mentioned first embodiment to the above-mentioned tenth embodiment in combination with each other.

The laser welding method according to one aspect of the present invention is a laser welding method in which a plurality of metal members are joined by laser welding, and the laser light is oscillated and the oscillated laser light is focused on a welded portion. The metal is provided with an irradiation step and a scanning step for scanning the spot of the laser beam, and the spot of the laser beam is continuously scanned outward while orbiting around the predetermined location. A dot-shaped welded portion in a plan view is formed by melting a member, and the amount of heat input by irradiation of the laser beam at the outer peripheral portion of the welded portion is at least a part region on the inner peripheral side of the outer peripheral portion. It should be lower than the amount of heat input in the inner peripheral part.

First, in the laser welding method according to the above aspect, since a plurality of metal members are joined by laser welding, the welding speed is faster, the thermal influence is less, and the metal member is less than the case where the metal members are joined by resistance welding. On the other hand, welding can be performed in a non-contact manner, processing efficiency is high, and rigidity can be increased by continuous welding.

Next, in the laser welding method according to the above aspect, in the scanning step, the spot of the laser beam is orbited around the predetermined portion to melt and stir the metal member of the portion to form the welded portion. Therefore, even if there is a gap between the metal members in the state before welding, the molten metal will flow into the gap between the metal members. Therefore, in the laser welding method according to the above aspect, even if there is a gap between the metal members in the state before welding, the molten metal fills the gap between the metal members, so that the metal members are gouged (underfilled) or melted down. Can be suppressed.

Further, in the laser welding method according to the above aspect, in forming the welded portion, the amount of heat input at the outer peripheral portion is set to be lower than the amount of heat input at the inner peripheral portion, so that the wall thickness of the outer peripheral portion of the welded portion is increased. It is possible to prevent the structure from becoming thin, becoming a fragile structure due to rapid cooling caused by the thinning, and increasing the residual stress.

Further, in the laser welding method according to the above aspect, since the scanning step is configured to continuously scan the spot of the laser beam up to the outer peripheral portion, the heat input amount of the outer peripheral portion is executed by executing two steps divided in time. Is lower than the amount of heat input to the inner peripheral portion, as compared with the technique disclosed in Patent Document 1, it is possible to suppress a long working time, and thus a decrease in working efficiency can be suppressed.

Therefore, in the laser welding method according to the above aspect, even when there is a gap between the metal members, it is possible to join the metal members with high bonding strength with high work efficiency.

In the laser welding method according to the above aspect, the scanning is performed so that the irradiation density of the laser beam on the outer peripheral portion is lower than the irradiation density of the laser beam on the inner peripheral portion, and the difference in the irradiation density is obtained. It is also possible to adopt a configuration in which the amount of heat input to the outer peripheral portion is made lower than the amount of heat input to the inner peripheral portion.

When the above configuration is adopted, the outer peripheral portion is thinned, fragilely organized, and the outer peripheral portion is thinned and fragilely organized while achieving high work efficiency by changing the irradiation density of the laser beam between the outer peripheral portion and the inner peripheral portion. It is possible to suppress an increase in residual stress.

In the laser welding method according to the above aspect, it is also possible to adopt a configuration in which the scanning locus of the spot of the laser beam is made so that the outer peripheral portion has a lower density than the inner peripheral portion.

When the above configuration is adopted, the density of the laser beam scanning locus in the outer peripheral portion is made sparser than that in the inner peripheral portion, so that the output of the laser light is kept constant and the outer peripheral portion is maintained. It is possible to reduce the amount of heat input at the above to that of the inner peripheral portion.

In the laser welding method according to the above aspect, it is also possible to adopt a configuration in which the scanning speed of the spot of the laser beam is made faster in the outer peripheral portion than in the inner peripheral portion.

When the above configuration is adopted, the amount of heat input in the outer peripheral portion is made lower than that in the inner peripheral portion by making the laser light scanning speed in the outer peripheral portion faster than that in the inner peripheral portion. Is possible.

In the laser welding method according to the above aspect, it is also possible to adopt a configuration in which the output of the laser beam is made lower in the outer peripheral portion than in the inner peripheral portion.

When the above configuration is adopted, the laser light output in the outer peripheral portion is made lower than that in the inner peripheral portion, so that the amount of heat input in the outer peripheral portion can be made lower than that in the inner peripheral portion. ..

In the laser welding method according to the above aspect, in the radial direction of the circumference, the welded portion includes an annular first annular portion located between the outer peripheral portion and the inner peripheral portion, and the outer peripheral portion and the first annular portion. An annular second annular portion located between the first annular portion is further included, the heat input of the first annular portion is lower than that of the inner peripheral portion, and the heat input of the second annular portion is the first. It is also possible to adopt a configuration in which the temperature is higher than the one annular portion and the outer peripheral portion.

When the above configuration is adopted, the thinning of the outer peripheral portion can be suppressed by suppressing the amount of heat input in the outer peripheral portion to be low, and the welded portion is located between the outer peripheral portion and the inner peripheral portion. The first annular portion and the second annular portion are included, the heat input amount of the first annular portion is lower than that of the inner peripheral portion, and the heat input amount of the second annular portion is higher than that of the outer peripheral portion and the first annular portion. By doing so (by adjusting the strength of the amount of heat input in the radial direction of the circumference), it is possible to suppress the amount of input energy even when welding is performed in a wide range.

The laser welding apparatus according to one aspect of the present invention is a laser welding apparatus for joining a plurality of metal members by laser welding, and is a laser oscillator that oscillates a laser beam and a condensing device that collects the laser beam on a welded portion. The control unit includes a unit, a scanning unit that scans the spot of the laser beam, and a control unit that controls the laser oscillator and the scanning unit, and the control unit has the spot of the laser beam centered on a predetermined location. By continuously scanning outward while rotating around the welded portion, a dot-shaped welded portion in a plan view in which the metal member is melted is formed, and the welding portion is entered by irradiation of the laser beam on the outer peripheral portion of the welded portion. The laser oscillator and the scanning unit are controlled so that the amount of heat is lower than the amount of heat input in the inner peripheral portion, which is at least a partial region on the inner peripheral side of the outer peripheral portion.

First, in the laser welding apparatus according to the above aspect, since a plurality of metal members are joined by laser welding, the welding speed is faster, the thermal influence is less, and the metal members are less affected than in the case of using resistance welding or the like. Welding can be performed in a non-contact manner, processing efficiency is high, and rigidity can be increased by continuous welding.

Next, in the laser welding apparatus according to the above aspect, the spot of the laser beam is circulated around the predetermined portion to melt and stir the metal member of the portion to form a welded portion. Even if there is a gap between the metal members in the previous state, the molten metal will flow into the gap between the metal members. Therefore, in the laser welding apparatus according to the above aspect, even if there is a gap between the metal members in the state before welding, the molten metal fills the gap between the metal members, so that the metal members are gouged (underfilled) or melted down. Can be suppressed.

Further, in the laser welding apparatus according to the above aspect, in forming the welded portion, the laser oscillator and the scanning portion are controlled so that the amount of heat input in the outer peripheral portion is lower than the amount of heat input in the inner peripheral portion. It is possible to prevent the thickness of the outer peripheral portion of the welded portion from becoming thin, the structure from becoming fragile due to quenching caused by the thinning, and the residual stress from becoming large.

Further, since the laser welding apparatus according to the above aspect is configured to continuously scan the spots of the laser beam toward the outside in the formation of the welded portion, the outer peripheral portion is executed by executing two steps divided in time. Suppressing thinning of the working time Compared with the technique disclosed in Patent Document 1, it is possible to suppress a long working time and suppress a decrease in working efficiency.

Therefore, in the laser welding apparatus according to the above aspect, even when there is a gap between the metal members, it is possible to join the metal members with high bonding strength with high work efficiency.

In the laser welding apparatus according to the above aspect, the control unit reduces the irradiation density of the laser beam in the outer peripheral portion to be lower than the irradiation density of the laser beam in the inner peripheral portion, thereby causing the outer peripheral portion. It is also possible to adopt a configuration in which the amount of heat input is lower than the amount of heat input of the inner peripheral portion.

When the above configuration is adopted, the outer peripheral portion is thinned, fragilely organized, and the outer peripheral portion is thinned and fragilely organized while achieving high work efficiency by changing the irradiation density of the laser beam between the outer peripheral portion and the inner peripheral portion. It is possible to suppress an increase in residual stress.

In the laser welding apparatus according to the above aspect, the control unit adopts a configuration in which the scanning locus of the spot of the laser beam is made so that the outer peripheral portion has a lower density than the inner peripheral portion. You can also do it.

When the above configuration is adopted, the density of the laser beam scanning locus in the outer peripheral portion is made sparser than that in the inner peripheral portion, so that the output of the laser light is kept constant and the outer peripheral portion is maintained. It is possible to reduce the amount of heat input at the above to that of the inner peripheral portion.

In the laser welding apparatus according to the above aspect, the control unit may adopt a configuration in which the scanning speed of the spot of the laser beam is made faster in the outer peripheral portion than in the inner peripheral portion. it can.

When the above configuration is adopted, the amount of heat input in the outer peripheral portion is made lower than that in the inner peripheral portion by making the laser light scanning speed in the outer peripheral portion faster than that in the inner peripheral portion. Is possible.

In the laser welding apparatus according to the above aspect, the control unit may adopt a configuration in which the output of the laser beam is made lower in the outer peripheral portion than in the inner peripheral portion.

When the above configuration is adopted, the laser light output in the outer peripheral portion is made lower than that in the inner peripheral portion, so that the amount of heat input in the outer peripheral portion can be made lower than that in the inner peripheral portion. ..

As described above, in each of the above aspects, even when there is a gap between the metal members, it is possible to join the metal members with high joining strength with high work efficiency.

Claims (11)

1. A laser welding method in which a plurality of metal members are joined by laser welding.
   A laser beam irradiation step that oscillates the laser beam and condenses the oscillated laser beam on the welded part.
   A scanning step of scanning the spot of the laser beam and
   With
   The spot of the laser beam is continuously scanned outward while orbiting around the predetermined location to form a dot-shaped welded portion in a plan view in which the metal member is melted, and the welded portion is formed. The amount of heat input by the irradiation of the laser beam on the outer peripheral portion of the outer peripheral portion is made lower than the amount of heat input of the inner peripheral portion which is at least a partial region on the inner peripheral side of the outer peripheral portion.
   Laser welding method.
2. In the laser welding method according to claim 1,
   The scanning is performed so that the irradiation density of the laser light in the outer peripheral portion is lower than the irradiation density of the laser light in the inner peripheral portion, and the amount of heat input in the outer peripheral portion is increased due to the difference in the irradiation density. Make it lower than the amount of heat input in the inner circumference,
   Laser welding method.
3. In the laser welding method according to claim 1 or 2.
   The scanning locus of the spot of the laser beam is made so that the outer peripheral portion has a lower density than the inner peripheral portion.
   Laser welding method.
4. In the laser welding method according to any one of claims 1 to 3.
   The scanning speed of the spot of the laser beam is set so that the outer peripheral portion is faster than the inner peripheral portion.
   Laser welding method.
5. In the laser welding method according to any one of claims 1 to 4.
   The output of the laser beam is set to be lower in the outer peripheral portion than in the inner peripheral portion.
   Laser welding method.
6. In the laser welding method according to any one of claims 1 to 5.
   In the radial direction of the circumference, the welded portion is located between the annular first annular portion located between the outer peripheral portion and the inner peripheral portion, and between the outer peripheral portion and the first annular portion. A second annular portion of the annular, and further included,
   The heat input amount of the first annular portion is lower than that of the inner peripheral portion, and the heat input amount of the second annular portion is higher than that of the first annular portion and the outer peripheral portion.
   Laser welding method.
7. A laser welding device that joins multiple metal members by laser welding.
   A laser oscillator that oscillates laser light and
   A condensing unit that collects the laser light on the welded part,
   A scanning unit that scans the spot of the laser beam,
   A control unit that controls the laser oscillator and the scanning unit,
   With
   The control unit forms a plan view dot-shaped welded portion in which a metal member is melted by continuously scanning the spot of the laser beam toward the outside while orbiting the spot around a predetermined location. At the same time, the laser oscillator so that the amount of heat input by irradiating the laser beam on the outer peripheral portion of the welded portion is lower than the amount of heat input of the inner peripheral portion which is at least a part region on the inner peripheral side of the outer peripheral portion. And control the scanning unit,
   Laser welding equipment.
8. In the laser welding apparatus according to claim 7.
   The control unit lowers the irradiation density of the laser beam on the outer peripheral portion to be lower than the irradiation density of the laser light on the inner peripheral portion, so that the amount of heat input to the outer peripheral portion is equal to that of the inner peripheral portion. Try to be lower than the amount of heat,
   Laser welding equipment.
9. In the laser welding apparatus according to claim 7 or 8.
   The control unit makes the scanning locus of the spot of the laser beam sparser in the outer peripheral portion than in the inner peripheral portion.
   Laser welding equipment.
10. In the laser welding apparatus according to any one of claims 7 to 9.
    The control unit makes the scanning speed of the spot of the laser beam faster in the outer peripheral portion than in the inner peripheral portion.
    Laser welding equipment.
11. In the laser welding apparatus according to any one of claims 7 to 10.
    The control unit makes the output of the laser beam lower in the outer peripheral portion than in the inner peripheral portion.
    Laser welding equipment.

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