JP2019150842A - Laser welding method - Google Patents

Abstract

To provide a laser welding method in which two metal parts can be melted and welded in an overlapping direction while moving an irradiation position of laser light, which can suppress increase in tact time while suppressing occurrence of burn-through.SOLUTION: In an irradiation step, a unit irradiation step comprised of first irradiation operation and second irradiation operation is repeatedly performed, where in the first irradiation operation, first laser light is emitted to form a first melted part 31 extending across the whole of a first metal member 10 in an overlapping direction and in the second irradiation operation, the irradiation position is moved in a predetermined moving direction while irradiating second laser light which is smaller in spot diameter than the first laser light into a region in the first melted part 31 to form a second melted part 32 extending up to a second metal member 20 along the moving direction. In the irradiation step, the irradiation position of the first laser light in the unit irradiation step performed first and the irradiation position of the first laser light in the unit irradiation step performed immediately after the step performed first are shifted along the moving direction, so that the melted parts to be formed in the unit irradiation steps are sequentially formed along the moving direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser welding method.

  As a conventional welding method, two metal plates are placed one above the other while irradiating the surface of the upper metal plate with laser light to form a molten portion in the overlapping direction and joining both metal plates There is a welding method to do. In this welding method, if there is a gap between the metal plates, when the upper metal plate is melted by laser light irradiation, the molten material easily flows into the gap, and the molten portion of the upper metal plate melts down. Problems such as thinning and holes are likely to occur. Therefore, conventional techniques such as Patent Documents 1 to 3 have been proposed.

  In the laser welding method disclosed in Patent Document 1, in the first laser irradiation, laser irradiation is performed in a defocused state out of focus, and an upper plate (upper metal plate) on the laser irradiation side in a place with a gap. The gap is reduced after being melted and dented to the lower plate (lower metal plate) side, and the upper plate and the lower plate are joined in a range that does not penetrate to the back side of the lower plate at a place where there is no gap. In the second time, laser irradiation is performed so as to form a melted portion that penetrates to the back side of the lower plate.

  In the laser welding method disclosed in Patent Document 2, the upper plate (upper metal plate) is melted while performing weaving in the first step, and in the second step performed after the first step, Through welding is performed through the lower plate (lower metal plate).

  In the member joining method disclosed in Patent Document 3, in the first laser irradiation step, a laser beam having a relatively large spot diameter is irradiated to the first plate-shaped portion (the upper metal plate) formed in an annular shape. By doing so, the melting part is formed so as to be continuous over the entire circumference of the first plate-like part. In the second laser irradiation step, after the melted portion formed in the first laser irradiation step is solidified and the melt-solidified portion is formed, the surface of the melt-solidified portion is irradiated with laser light, and the melt-solidified portion And the second plate-like portion (lower metal plate) are melted to form a welded portion.

JP 2010-23047 A Japanese Unexamined Patent Publication No. 2015-30018 JP 2014-147862 A

  However, in the laser welding method disclosed in Patent Document 1, when welding a predetermined range, laser irradiation in a defocused state is performed over a predetermined range in the first laser irradiation, and a lower plate is formed in the second laser irradiation. Laser irradiation is performed over a predetermined range to form a molten region that penetrates to the back side of the substrate. That is, when a continuous or intermittent joint is formed in a predetermined range (welding range), laser scanning must be performed at least twice, which leads to an increase in tact time.

  In the laser welding method disclosed in Patent Document 2, the operation of switching the focal length as in Patent Document 1 is unnecessary, but preliminary laser irradiation performed in the first step (the upper plate is melted to the lower plate). Since it is necessary to perform weaving by preliminary laser irradiation to be brought into contact, it takes time to move by weaving as compared with a method of irradiating laser light having a spot diameter covering the weaving range. Moreover, when this method is applied to a method of joining over a predetermined range while moving the laser beam irradiation position in a predetermined direction (so-called continuous welding, etc.), the weaving range is moved in the predetermined direction while the upper plate is melted by weaving. Must be more time consuming.

  In the laser welding method disclosed in Patent Literature 3, after forming a melted portion that is continuous over the entire circumference of the first plate-like portion (upper plate), and forming a melt-solidified portion in which the melted portion is solidified, The laser beam is irradiated again to melt the melt-solidified portion and the second plate-like portion. In such a method, it is necessary to irradiate the same region twice with laser, and it is necessary to secure a time until the melted portion is solidified. As a result, the tact time is increased.

  The present invention has been made to solve at least a part of the above-described problems, and in a laser welding method capable of melting and joining two metal parts in an overlapping direction while moving an irradiation position of a laser beam, It is an object to realize a method capable of suppressing an increase in tact time while suppressing occurrence of dropping.

The laser welding method which is one of the present invention,
An arrangement step of arranging a first opposing surface of the first metal member and a second opposing surface of the second metal member facing each other and placing the first metal member on the second metal member;
In the overlapping direction of the first metal member and the second metal member by irradiating laser light toward the upper surface opposite to the first opposing surface of the first metal member arranged in the arrangement step An irradiation step of forming a melted portion extending from the first metal member to the second metal member;
A laser welding method comprising:
The irradiation step includes
Irradiating a first laser beam on the upper surface, thereby forming a first irradiation operation that forms a first molten portion that covers the entire first metal member in the overlapping direction;
The irradiation position of the second laser beam is predetermined while irradiating the second laser beam with a spot diameter smaller than that of the first laser beam in the region of the first melted part formed by the first irradiation operation. A second irradiation operation for forming the second molten portion extending to the second metal member in the overlapping direction so as to follow the moving direction by moving in the moving direction of
A unit irradiation process consisting of:
The unit irradiation step is performed first so as to start the first irradiation operation in the unit irradiation step performed immediately after the first irradiation operation in the unit irradiation step performed first is completed. The first laser beam in the unit irradiation step that is repeated first is repeated so as to start the second irradiation operation in the unit irradiation step that is performed immediately after the second irradiation operation in the unit irradiation step is completed. By shifting the irradiation position of the first laser beam in the unit irradiation step performed immediately after the irradiation position along the moving direction, the melting portion formed by the unit irradiation step is moved along the moving direction. Sequentially formed.

In the laser welding method, a unit irradiation process including a first irradiation operation and a second irradiation operation is repeatedly performed. In the first irradiation operation, the first laser is formed with a relatively large spot diameter with respect to the upper surface of the first metal member. By irradiating with light, the 1st fusion part covering the whole 1st metal member is formed in the overlap direction.
When the first melting portion is formed in this way, the molten material in the first melting portion is gravity-induced when there is a gap between the first facing surface of the first metal member and the second facing surface of the second metal member. It moves to the gap side under the influence of and acts to fill the gap. Since the first melting part is a melting part formed with a relatively large spot diameter, the amount of melting of the first melting part can be increased. For this reason, even if the melted material moves to the gap side in the first melted portion formed in the first metal member, the melt-off hardly occurs.
In the second irradiation operation, the second laser beam is irradiated with the second laser beam at a spot diameter smaller than that of the first laser beam in the region of the first melted part formed in the first irradiation operation. By moving the irradiation position in a predetermined movement direction, the second melting part extending to the second metal member in the overlapping direction is formed along the movement direction.
In this way, the second metal member is filled with the second metal member in such a manner that the first metal member is unlikely to melt down, while the second metal member is filled with the second metal member. By the irradiation operation, it is possible to form a deeper second melting portion that straddles the first metal member and the second metal member. Therefore, both metal parts can be joined by forming a deep melted part while suppressing the occurrence of melt-down.
Furthermore, the second irradiation operation in the unit irradiation process performed first is started so as to start the first irradiation operation in the unit irradiation process performed immediately after the first irradiation operation in the unit irradiation process performed in the first is completed. The unit irradiation step is repeated so as to start the second irradiation operation in the unit irradiation step performed immediately after the completion of the step, and the unit irradiation step performed immediately after the irradiation position of the first laser light in the unit irradiation step performed first. By shifting the irradiation position of the first laser beam in the direction along the moving direction, the melted portion formed by the unit irradiation step is sequentially formed along the moving direction.
In this case, by repeating the unit irradiation process, the first melting portion is sequentially formed along the moving direction while the first irradiation operation is performed intermittently, and the second irradiation operation is performed while the second irradiation operation is performed intermittently. Since the process of sequentially forming the two melted portions along the moving direction is continued, it is possible to sequentially form the joint portions along the moving direction while effectively suppressing an increase in tact time. .

In the laser welding method of one embodiment of the present invention, the first irradiation operation and the second irradiation operation may be performed by the same laser beam irradiation apparatus in the irradiation step.
By using this method, the first irradiation operation and the second irradiation operation can be performed by a common laser light irradiation apparatus, and two types of irradiation operations can be realized while simplifying the configuration.

In the laser welding method of one embodiment of the present invention, in the irradiation process, the first irradiation operation and the second irradiation operation are periodically performed, and the irradiation range of the second laser beam in the unit irradiation process performed first and immediately after The second irradiation operation may be performed so as to partially overlap the irradiation range of the second laser light in the unit irradiation step performed in step (b).
If this method is used, the second melted portion can be continuously formed along the moving direction, so that stronger bonding is possible.

In the laser welding method of one embodiment of the present invention, in the irradiation process, the first irradiation operation and the second irradiation operation are periodically performed, and the irradiation range of the second laser beam in the unit irradiation process performed first and immediately after The second irradiation operation may be performed so as to be separated from the irradiation range of the second laser light in the unit irradiation step performed in step (b).
If this method is used, it will become easy to form a 2nd fusion | melting part over a wider range, shortening the time which 2nd irradiation operation | movement is performed.

In the laser welding method of one embodiment of the present invention, in the irradiation process, the first irradiation is performed such that the second irradiation operation is started at the end of the first irradiation operation and the first irradiation operation is started at the end of the second irradiation operation. The operation and the second irradiation operation may be switched alternately.
If this method is used, the irradiation period of the first laser beam and the irradiation period of the second laser beam do not overlap. Therefore, when the second melted part is formed by the second laser light, the thermal effect of the first melted part is affected. It becomes easy to suppress.

In the laser welding method of one embodiment of the present invention, in the irradiation step, a first period in which only the first irradiation operation among the first irradiation operation and the second irradiation operation is performed, and a second period in which only the second irradiation operation is performed. Alternately, at least one of the third period from the end of the first period to the start of the second period, or the fourth period from the end of the second period to the start of the first period During this period, the first irradiation operation and the second irradiation operation may be performed in parallel.
If this method is used, the first irradiation operation and the second irradiation operation can be performed in parallel during a part of the period, so that the execution cycle of the first irradiation operation and the second irradiation operation can be easily shortened. An increase in tact time can be further suppressed.

In the laser welding method of one embodiment of the present invention, in the irradiation process, when the second laser light is output in the second period in at least a part of the period in which the first irradiation operation and the second irradiation operation are performed in parallel. The output of the second laser beam may be smaller.
If this method is used, it is possible to perform the first irradiation operation and the second irradiation operation in parallel, while excessively causing the first laser beam and the second laser beam to be irradiated at the same time. Melting can be suppressed.

In the laser welding method of one embodiment of the present invention, in the irradiation step, the first irradiation operation and the second irradiation operation are performed in parallel in the third period, and the output of the second laser light is equal to or lower than the output in the second period. In the fourth period, the first irradiation operation and the second irradiation operation are performed in parallel, and the output of the second laser beam is equal to or lower than the output in the second period. Then, the second irradiation operation may be performed so as to gradually decrease.
As described above, if the first irradiation operation and the second irradiation operation are performed in parallel in both the third period and the fourth period, the execution cycle of the first irradiation operation and the second irradiation operation is further shortened. The tact time can be further reduced. In addition, in the third period, the output of the second laser beam is gradually increased, and in the fourth period, the output of the second laser beam is gradually decreased. In the period, the output is suppressed as the time is late. In the third period, the earlier the timing, the greater the concern about the thermal effect due to the first irradiation operation. In the fourth period, the slower the timing, the greater the concern about the thermal effect due to the first irradiation operation. The effect of mitigating the influence can be further enhanced.

  According to the present invention, when the two metal parts are melted and joined in the overlapping direction while moving the irradiation position of the laser beam, an increase in tact time can be suppressed while suppressing the occurrence of burnout.

It is explanatory drawing which illustrates notionally the laser welding apparatus which concerns on 1st Embodiment, showing the structure which looked at the welding target object from the side. It is a block diagram which shows simply the structure of the laser welding apparatus which concerns on 1st Embodiment. It is explanatory drawing which shows notionally the specific example of the laser oscillator, switching part, and transmission part in the laser welding apparatus of FIG. (A) is explanatory drawing which illustrates notably the part of the laser welding method which concerns on 1st Embodiment, showing the structure which looked at the welding target object side view. (B) is explanatory drawing which illustrates notably the part of the laser welding method which concerns on 1st Embodiment, showing the structure which planarly viewed the welding target object. (A) is an explanation conceptually explaining the relationship between the irradiation region in the first irradiation operation and the irradiation region in the second irradiation operation when the laser welding method according to the first embodiment is performed, (B) is the laser beam irradiation timing by the first irradiation operation, the laser beam irradiation timing by the second irradiation operation, the laser beam output at the first irradiation operation, and the laser beam output at the second irradiation operation. It is a timing chart which shows the relationship. (A) is explanatory drawing explaining a mode that a 1st fusion | melting part is formed by 1st irradiation operation | movement, (B) is explanatory drawing explaining a mode that a 2nd fusion | melting part is formed by 2nd irradiation operation | movement. is there. It is a block diagram which shows simply the structure of the laser welding apparatus which concerns on 2nd Embodiment. It is explanatory drawing which shows notionally the specific example of the laser oscillator, the induction | guidance | derivation part, and transmission part in the laser welding apparatus of FIG. (A) is an explanation conceptually explaining the relationship between the irradiation region in the first irradiation operation and the irradiation region in the second irradiation operation when performing the laser welding method according to the second embodiment, (B) is the laser beam irradiation timing by the first irradiation operation, the laser beam irradiation timing by the second irradiation operation, the laser beam output at the first irradiation operation, and the laser beam output at the second irradiation operation. It is a timing chart which shows the relationship. It is description explaining notionally the relationship between the irradiation area | region in 1st irradiation operation | movement, and the irradiation area | region in 2nd irradiation operation | movement when performing the laser welding method which concerns on other embodiment.

1. 1. First embodiment 1-1. Laser Welding Device An example of a laser welding device used for carrying out the laser welding method will be described with reference to FIG.
A laser welding apparatus 1 shown in FIG. 1 is an apparatus capable of welding a plurality of metal parts as a welding object.

  In the example of FIG. 1, the welding object W is configured by the first metal plate 110 and the second metal plate 120, and the entire first metal plate 110 corresponds to the first metal member 10 as one welding object, The entire second metal plate 120 corresponds to the second metal member 20 as the other welding target. The first metal member 10 and the second metal member 20 are both formed in a plate shape, the surface on one side in the thickness direction of the first metal member 10 corresponds to the upper surface 10A, and the surface on the other side in the thickness direction is the first. It corresponds to the facing surface 10B. Further, the surface on one side in the thickness direction of the second metal member 20 corresponds to the second facing surface 20A, and the surface on the other side in the thickness corresponds to the lower surface 20B. The first facing surface 10 </ b> B is a surface facing the second metal member 20 in the first metal member 10. The second facing surface 20 </ b> A is a surface facing the first metal member 10 in the second metal member 20. The upper surface 10A is a surface opposite to the first facing surface 10B in the first metal member 10. In the example of FIG. 1, the first metal member 10 is stacked on the upper side in the vertical direction of the second metal member 20 so that the thickness direction of the first metal member 10 and the thickness direction of the second metal member 20 are the overlapping direction. The welding object W is configured such that the first facing surface 10B of the first metal member 10 and the second facing surface 20A of the second metal member 20 face each other.

  The laser welding apparatus 1 is an apparatus that can perform so-called “overlap welding” by irradiating a laser beam onto a welding object W that is in an overlapping state as shown in FIG. 1. The laser welding apparatus 1 irradiates laser light toward the upper surface 10 </ b> A of the first metal member 10, so that the first metal member 10 and the second metal member 20 overlap each other in the overlapping direction of the first metal member 10 and the second metal member 20. The melted part 30 extending to the metal member 20 is formed, and the first metal member 10 and the second metal member 20 can be joined.

  As shown in FIG. 1, the laser welding apparatus 1 mainly includes a control device 70, a laser light irradiation device 80, and a moving device 90.

  The control device 70 is an information processing device that can control each part of the laser welding apparatus 1. The control device 70 includes an arithmetic device such as a CPU, a storage unit such as a RAM and a ROM, other peripheral circuits, and the like. The control device 70 can control the laser light irradiation device 80, the moving device 90, and the like.

  The laser light irradiation device 80 is a device configured to generate laser light and emit laser light from the processing head 82 (emission unit). The laser beam irradiation device 80 can irradiate the processing head 82 with two types of laser beams, a first laser beam having a relatively large spot diameter and a second laser beam having a relatively small spot diameter. ing.

  In this specification, the “spot diameter” means that the irradiation surface (specifically, the surface of the first metal member 10) that is the surface irradiated with the laser light on the welding target W is irradiated with the laser light. It is the diameter of the irradiation range on the irradiation surface. For example, the spot diameter (first spot diameter) of the first laser light is the diameter of the first laser light irradiation range on the irradiation surface when the irradiation surface of the welding object W is irradiated with the first laser light. . The spot diameter (second spot diameter) of the second laser light is the diameter of the second laser light irradiation range on the irradiation surface when the second laser light is irradiated on the irradiation surface of the welding object W. . In this configuration, the first laser beam is a laser beam having a relatively wide irradiation range on the irradiation surface when the irradiation surface of the welding object W is irradiated, and the second laser beam is a beam of the welding object W. When the irradiation surface is irradiated, the irradiation range on the irradiation surface is a laser beam that is narrower than the irradiation range of the first laser beam.

  The laser beam irradiation device 80 includes a laser oscillator 84 including a direct diode laser oscillator (DDL oscillator), a fiber laser oscillator, and the like. The laser oscillator 84 is configured as a semiconductor laser oscillator, oscillates a laser diode, and outputs laser light having a predetermined wavelength that can be used for laser welding.

  As shown in FIG. 3, the switching unit 86 includes a mirror 86A that reflects the laser beam output from the laser oscillator 84, and a drive unit 86B that drives the mirror 86A. The drive unit 86B operates in response to an instruction from the control device 70, and reflects the tilt angle of the mirror 86A with respect to the laser beam from the laser oscillator 84, the angle at which the reflected laser beam enters the first core unit 89A, which will be described later, The angle at which the laser beam is incident on the second core portion 89B described later can be switched. Instead of the mirror 86A, a switching unit 86 may be used that includes an acousto-optic element that can adjust the direction of transmitted laser light by applying a voltage to change the refractive index in the element.

  The transmission unit 88 includes an optical fiber 88A configured as, for example, a double core fiber. The optical fiber 88A is a member capable of transmitting incident laser light to the processing head 82 side, and covers the fiber-shaped second core portion 89B disposed in the center and the fiber-shaped second core portion 89B in a cylindrical shape. A first core unit 89A. In the optical fiber 88A, a first cladding part 89C is provided between the first core part 89A and the second core part 89B, and a second cladding part 89D is provided so as to cover the outer peripheral surface of the first core part 89A. ing. Further, an exterior part 89E made of resin is provided so as to cover the outer peripheral surface of the second cladding part 89D. The first core portion 89A is a portion that generates laser light having a relatively large beam diameter, and the second core portion 89B is a portion that generates laser light having a relatively small beam diameter. That is, the laser light (laser light having a large beam diameter) emitted from the machining head 82 through the first core part 89A is the first laser light having a relatively large spot diameter, and the second core part 89B is Laser light (laser light having a small beam diameter) emitted from the machining head 82 is the second laser light having a relatively small spot diameter.

  The moving device 90 is a device that can change the laser light irradiation position on the welding object W. The moving device 90 may be a device that moves the processing head 82 (emission unit), and is a device that scans the laser light by displacing a mirror (such as a galvano mirror) that reflects the laser light. Alternatively, it may be configured as a device combining these. Or the apparatus which can change the irradiation position of the laser beam with respect to the welding target object W relatively by moving the holding | maintenance part holding the welding target object W may be sufficient. In the following description, an example in which the moving device 90 is configured as a device that can move the machining head 82 will be described as a representative example.

1-2. Laser Welding Method Next, a laser welding method performed using the laser welding apparatus 1 described above will be described.
The laser welding method described below is a method applied as one step of a method for manufacturing a joined body (a joined body in which the first metal member 10 and the second metal member 20 are joined).

First, the arrangement | positioning process performed before the irradiation process is demonstrated.
In the arranging step, as shown in FIG. 4A, the first facing surface 10B of the first metal member 10 and the second facing surface 20A of the second metal member 20 are opposed to each other, and the first metal member 10 is moved to the second metal. While being placed on the member 20, it is held in a stacked state. In the example of FIG. 4A, the plate thickness direction of both metal parts (the first metal member 10 and the second metal member 20) configured in a plate shape is the overlap direction, and specifically, the overlap direction is vertical. The first metal member 10 and the second metal member 20 are arranged so as to be in the vertical direction. The welding object W arranged in this way is held by a holding unit (mounting table or the like) (not shown) and positioned at a predetermined position.

  After performing such an arrangement process, an irradiation process is performed. In the irradiation step, a laser beam (specifically, the first laser beam and the first laser beam) is directed toward the upper surface 10A (the surface opposite to the first facing surface 10B in the thickness direction) of the first metal member 10 arranged in the arrangement step. This is a step of forming the melted portion 30 extending from the first metal member 10 to the second metal member 20 in the overlapping direction of the first metal member 10 and the second metal member 20 by irradiating the second laser beam. FIG. 4B conceptually shows the melted part 30 formed at a predetermined timing. In the irradiation process, the melted part similar to the melted part 30 is sequentially formed along the moving direction indicated by the arrow. .

  In the irradiation process, the first irradiation operation and the second irradiation operation are performed by the laser beam irradiation apparatus 80. As described above, the laser beam irradiation device 80 can irradiate the processing head 82 with the first laser beam having a relatively large beam diameter and the second laser beam having a relatively small beam diameter. In the first irradiation operation, the first laser light is irradiated from the processing head 82 along the predetermined axis L, and in the second irradiation operation, the second laser light is irradiated from the processing head 82 along the axis L. In the irradiation step, the first irradiation operation and the second irradiation operation are alternately switched so that the second irradiation operation is started after the end of the first irradiation operation and the first irradiation operation is started after the end of the second irradiation operation. .

  FIG. 5A conceptually shows a laser light irradiation region at each timing on the upper surface 10A of the first metal member 10, and FIG. 5B shows an on / off period of the first irradiation operation and the second irradiation. The operation on / off period, the output of the first laser beam, and the output of the second laser beam are shown. In the example of FIG. 5, as the irradiation range of the first laser beam on the surface of the first metal member 10, the range at the time t1 is indicated by a symbol S1a, the range at the time t2 is indicated by a symbol S1b, and the time t3 The range at time t4 is denoted by reference numeral S1c, and the range at time t4 is denoted by reference numeral S1d. Further, as the irradiation range of the second laser light on the surface of the first metal member 10, the range at time t2 is indicated by S2a, the range at time t3 is indicated by symbol S2b, and the range at time t4 is indicated by The range at time t5 is indicated by reference symbol S2d, the range at time t6 is indicated by reference symbol S2e, and the range at time t7 is indicated by reference symbol S2f. The ranges S1a, S1b, S2a, and S2b are indicated by solid lines, but the other ranges are indicated by two-dot chain lines.

  In the laser welding method according to the present embodiment, a first control signal (a signal for instructing a first irradiation operation) is periodically given from the control device 70 to the laser light irradiation device 80, as shown in FIG. In addition, a period Ta for performing the first irradiation operation is set at a constant cycle. In the example of FIG. 5B, the period Ta is T. The laser beam irradiation device 80 irradiates the first laser beam (laser beam irradiated with a relatively large spot diameter) intermittently continuously or in a short cycle in each period Ta set with a constant cycle. However, when the first laser beam is irradiated intermittently with a short period, the irradiation period is made sufficiently shorter than the period T. In this specification, the combination of the first irradiation operation and the second irradiation operation that starts during or immediately after the first irradiation operation is a “unit irradiation step”. The unit irradiation process is repeated. For example, in the example of FIG. 5B, one unit irradiation process period is from the start timing of the period Ta to the end timing of the period Tb immediately after the period Ta. Specifically, the time t1 From time t3 to time t3 is one unit irradiation process period, from time t3 to time t5 is one unit irradiation process period, and from time t5 to time t7 is one unit irradiation process period. In the example of FIG. 5, the unit irradiation is performed while matching the end timing of the second irradiation operation period in the unit irradiation process performed first with the start timing of the first irradiation operation period in the unit irradiation process performed immediately thereafter. The process is repeated.

  The output of the first laser beam and the irradiation period Ta are such that when the first laser beam is irradiated onto the upper surface 10A, the first melting part 31 extends over the entire first metal member 10 in the thickness direction (overlapping direction). Is set. In the example of FIG. 5B, the output of the first laser beam is set to a predetermined high level in the period Ta, and the output of the second laser beam is set to a predetermined high level in the period Tb. The output of the first laser beam in the period Ta is set to be larger than the output of the second laser beam in the period Tb. Specifically, as shown in FIG. 6A, the first molten portion 31 is formed only in the vicinity of the second facing surface 20 </ b> A of the second metal member 20 by the first laser light, or the second metal. The length of the period Ta and the output of the first laser beam in the period Ta (predetermined high level) are set to such an extent that the first melting part 31 is not formed on the member 20. In other words, the length of the period Ta and the output of the first laser beam in the period Ta (predetermined high level) so that the size of the gap between the first facing surface 10B and the second facing surface 20A is reduced. Is set. In FIG. 6A, the first laser beam is conceptually indicated by reference numeral L1.

  In this way, the control device 70 causes the laser light irradiation device 80 to periodically perform the first irradiation operation, gives an instruction to the movement device 90 to perform the movement operation in parallel with this operation, and causes the machining head 82 to move. An operation of moving in a predetermined “movement direction” is performed. That is, in the laser welding apparatus 1, the laser beam irradiation device 80 periodically performs the first irradiation operation while the movement device 90 performs the operation of moving the machining head 82 in the “movement direction”. Yes. Since such control is performed, every time the first irradiation operation is performed (that is, every cycle), the irradiation position of the first laser beam moves in the “movement direction” on the upper surface 10A, and the first melting portion 31 moves It is formed sequentially along the moving direction. In the example of FIG. 5, the irradiation range of the first laser light is changed to a range S1a, a range S1b, a range S1c, and a range S1d as time elapses, and the first melting portion 31 is sequentially formed below each range. It will be.

  Further, as shown in FIG. 5B, the control device 70 sends a second control signal (a signal for instructing the second irradiation operation) to the laser beam irradiation device 80 in each period Tb in which the first irradiation operation is paused. The second irradiation operation is alternately performed with the first irradiation operation. The laser beam irradiation device 80 performs the second irradiation operation in each period Tb according to the second control signal. That is, each period (that is, each period when the first control signal is not given) Tb during which the first irradiation operation is paused is a period during which the laser beam irradiation apparatus 80 performs the second irradiation operation. The second irradiation operation is an operation of irradiating the second laser beam having the second spot diameter continuously or intermittently in a short cycle, and the region of the first melting part 31 on the irradiation surface as shown in FIG. 6B. This is an operation for forming the second melting portion 32 therein. The second melting part 32 is a melting part that extends to the second metal member 20 in the thickness direction (overlapping direction) of the first metal member 10 and the second metal member 20. In FIG. 6B, the second laser light is conceptually indicated by reference numeral L2.

  As shown in FIG. 5A, when the surface of the first metal member 10 is irradiated with the first laser light, the spot diameter (first spot diameter) on the surface is more likely to be the second laser light than the first metal. Irradiation from the machining head 82 when the machining head 82 is moving in the “movement direction”, which is larger than the spot diameter (second spot diameter) on the surface when the surface of the member 10 is illuminated. When the light is switched from the first laser light to the second laser light, the second laser light emitted immediately after the switching is irradiated to the first melting part 31 formed by the latest first irradiation operation, and the processing head 82 According to the movement, the irradiation position of the second laser beam moves in a predetermined direction (movement direction) within the region of the first melting part 31 (the first melting part 31 formed by the latest first irradiation operation). Become.

  For example, when the laser beam emitted from the machining head 82 is switched from the first laser beam to the second laser beam at time t2 shown in FIG. 5B, the second laser beam emitted immediately after the switching is the latest laser beam. The first melting part 31 formed by the first irradiation operation (that is, the first melting part 31 corresponding to the moving range from the range S1a to the range S1b) is irradiated, and the irradiation position of the second laser light is Within the region of the first melting part 31, the region moves along the “movement direction” from the range S2a to the range S2b.

  In this way, the second irradiation operation is performed so as to move the irradiation position of the second laser light in the “movement direction” while irradiating the first melting portion 31 formed by the latest first irradiation operation with the second laser light. By performing, the 2nd fusion | melting part 32 (The fusion | melting part which extends to the position deeper than the 1st fusion | melting part 31 in an overlapping direction) is formed in the 1st metal member 10 and the 2nd metal member 20 sequentially along a moving direction. Can do. The length of the period Tb and the output of the second laser beam in the period Tb are set so that the second melting part 32 is formed at a desired depth when the first laser beam is irradiated onto the first melting part 31. Specifically, the second melting part 32 is formed so as to straddle the first metal member 10 and the second metal member 20 in the overlapping direction (thickness direction), and the second melting part 31 is deeper than the first melting part 31. Two melting parts 32 are set to cover. In the example of FIG. 6, the first melting portion 31 is formed so as not to reach the lower surface 20B side from the center position (thickness direction center position) of the second metal member 20 in the thickness direction (overlapping direction), The second melting part 32 is formed so as to extend to the lower surface 20B side from the center position (thickness direction center position) of the second metal member 20.

  In the example of FIG. 5, the second irradiation operation is performed in the irradiation period Tb set periodically, and the second laser light is periodically irradiated. However, the second laser light in each period The second irradiation operation is performed so that the irradiation range partially overlaps the irradiation range of the second laser light in the previous cycle. For example, in a certain cycle, the second irradiation operation is performed in a period from time t2 to time t3, and a second melting part extending from the range S2a to the range S2b in the moving direction is formed. Then, in the next cycle, the second irradiation operation is performed in the period from time t4 to time t5, and the second melting part extending from the range S2c to the range S2d in the moving direction is formed. Further, in the next cycle, the second irradiation operation is performed in the period from time t6 to time t7, and the second melting part extending from the range S2e to the range S2f in the moving direction is formed. In this example, the second laser light irradiation range S2b at the end of the second irradiation operation in a certain period (period in which the second irradiation operation period Tb from time t2 to time t3 is set) and the next period (time) The second laser light irradiation range S2c at the start point of the second irradiation operation in the second irradiation operation period Tb from t4 to time t5 is overlapped. Similarly, the second laser light irradiation range S2d at the end of the second irradiation operation in a certain period (period in which the second irradiation operation period Tb from time t4 to time t5 is set) and the next period (time t6). To the time t7 in the second irradiation operation period Tb), the second laser light irradiation range S2e at the start of the second irradiation operation overlaps. As described above, the irradiation region of the second laser light at the time when the second irradiation operation ends in a certain cycle and the irradiation region of the second laser light at the time when the second irradiation operation starts in the next cycle are obtained. Since it overlaps, even if it performs 2nd irradiation operation | movement periodically, the 2nd fusion | melting part 32 can be continuously formed in the welding target object W along a moving direction.

1-3. Action / Effect In the laser welding method described above, the unit irradiation process including the first irradiation operation and the second irradiation operation is repeated, and the first irradiation operation is relatively large with respect to the upper surface 10A of the first metal member 10. By irradiating the first laser beam with the spot diameter, the first molten portion 31 that extends over the entire first metal member 10 in the overlapping direction is formed. When the first melting portion 31 is formed in this way, when there is a gap between the first facing surface 10B of the first metal member 10 and the second facing surface 20A of the second metal member 20, the first melting portion 31 is formed. The molten material 31 moves to the gap side under the influence of gravity and acts to fill the gap. Since the first melting part 31 is a melting part formed with a relatively large spot diameter, the amount of melting of the first melting part 31 can be increased. For this reason, even if an action occurs in which the molten material moves to the gap side in the first melting portion 31 formed in the first metal member 10, the melting-down hardly occurs.

  In addition, when the 1st fusion | melting part 31 is formed by 1st irradiation operation and a molten material is moved so that the clearance gap between the 1st opposing surface 10B and the 2nd opposing surface 20A may be filled, the effect of reducing a clearance gap is acquired. If so, the molten material of the first melting part 31 may not necessarily be in close contact with the second facing surface 20A. Of course, the molten material may be in close contact with the second facing surface 20A.

In the second irradiation operation, the second laser beam is irradiated while irradiating the second laser beam with a spot diameter smaller than that of the first laser beam in the region of the first melting portion 31 formed in the first irradiation operation. By moving the irradiation position in a predetermined movement direction, the second melting part 32 extending to the second metal member 20 in the overlapping direction is formed along the movement direction. In this way, a gap (gap between the first facing surface 10B of the first metal member 10 and the second facing surface 20A of the second metal member 20) is formed in such a manner that the first metal member 10 is not easily melted down. While filling, the second melting portion 32 straddling the first metal member 10 and the second metal member 20 can be formed deeper by the second irradiation operation. Therefore, both metal parts can be joined by forming a deeper melted part while suppressing the occurrence of burn-through.
Furthermore, the second irradiation operation in the unit irradiation process performed first is started so as to start the first irradiation operation in the unit irradiation process performed immediately after the first irradiation operation in the unit irradiation process performed in the first is completed. The unit irradiation step is repeated so as to start the second irradiation operation in the unit irradiation step performed immediately after the completion of the step, and the unit irradiation step performed immediately after the irradiation position of the first laser light in the unit irradiation step performed first. By shifting the irradiation position of the first laser beam in the direction along the moving direction, the melted portion formed by the unit irradiation step is sequentially formed along the moving direction. In this case, by repeating the unit irradiation process, the first melting part 31 is sequentially formed along the moving direction while the first irradiation operation is performed intermittently, and the second irradiation operation is performed intermittently. Since the process of sequentially forming the second melting portion 32 along the moving direction is continued, it is possible to sequentially form the joint portion along the moving direction while effectively suppressing an increase in tact time. Can do.

  In addition, when irradiating the 2nd laser beam with respect to the 1st fusion | melting part 31 formed by 1st irradiation operation | movement, the 1st fusion | melting part 31 is started at the time of the 2nd irradiation operation start time (2nd laser light irradiation start time). Is not necessarily solidified. Of course, the first melting part 31 may be solidified at the start of the second irradiation operation.

  In the irradiation process, the first irradiation operation and the second irradiation operation can be performed by the same laser beam irradiation apparatus 80. More specifically, the laser beam irradiation device 80 in which the first laser beam in the first irradiation operation and the second laser beam in the second irradiation operation are emitted from a common processing head 82 can be used. In this way, two types of irradiation operations can be realized while simplifying the configuration.

  In the irradiation process, the first irradiation operation and the second irradiation operation are periodically performed, and the irradiation range of the second laser light in the unit irradiation process performed first and the unit irradiation process performed immediately thereafter are performed. The second irradiation operation can be performed so as to partially overlap the irradiation range of the two laser beams. In this way, the second melting part 32 can be continuously formed along the moving direction, so that stronger bonding is possible.

  In the irradiation process, the first irradiation operation and the second irradiation operation are alternately performed so that the second irradiation operation is started at the end of the first irradiation operation and the second irradiation operation is started at the end of the second irradiation operation. It has been switched to. In this case, the period for irradiating the first laser beam and the period for irradiating the second laser beam do not overlap. Therefore, when forming the second melted part 32 with the second laser beam, the first melted part 31 is formed. It becomes easy to suppress the heat effect.

2. Second Embodiment Next, a second embodiment will be described.
2-1. Laser Welding Device A laser welding device 201 according to the second embodiment shown in FIG. 7 includes a control device 70, a laser light irradiation device 280, and a moving device 90. In the laser welding apparatus 201, the control device 70 and the moving device 90 have the same configuration as the control device 70 and the moving device 90 of the laser welding apparatus 1 (see FIG. 1 and the like) according to the first embodiment, and function similarly. To do. Therefore, about these, the same code | symbol as the laser welding apparatus 1 which concerns on 1st Embodiment is attached | subjected, and detailed description is abbreviate | omitted. Moreover, the welding target object W also has the same configuration as the welding target object W used in the laser welding method according to the first embodiment. Therefore, the welding object W is also denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted. In addition, the outline of the laser welding method performed using the laser welding apparatus 201 is the same as that of FIG. 1, FIG. 4, and FIG. Therefore, in the following description, FIGS. 1, 4 and 6 will be referred to as appropriate.

  In the laser welding apparatus 201 shown in FIG. 7, the laser beam irradiation apparatus 280 includes a first laser oscillator 284A, a second laser oscillator 284B, a first induction unit 286A, a second induction unit 286B, a transmission unit 88, and the like. The transmission unit 88 has the same configuration as the transmission unit 88 of the laser welding apparatus 1 (see FIG. 2 and the like) according to the first embodiment. Therefore, about the transmission part 88, the code | symbol same as the laser welding apparatus 1 which concerns on 1st Embodiment is attached | subjected, and detailed description is abbreviate | omitted.

  The laser beam irradiation device 280 is a device configured to generate laser beams and emit laser beams from the processing head 82 (emission unit) as shown in FIG. 4, and is a first laser having a relatively large beam diameter. Two types of laser light, that is, light (laser light having a relatively large spot diameter) and laser light having a second relatively small beam diameter (laser light having a relatively small spot diameter) are processed by the machining head 82. It is possible to irradiate from.

  As shown in FIG. 7, the laser beam irradiation device 280 includes a first laser oscillator 284A and a second laser oscillator 284B made of a fiber laser oscillator or the like. Each of the first laser oscillator 284A and the second laser oscillator 284B is configured as a semiconductor laser oscillator, oscillates a laser diode, and outputs laser light having a predetermined wavelength that can be used for laser welding.

  The first guiding unit 286A and the second guiding unit 286B function to guide each laser beam from the first laser oscillator 284A and the second laser oscillator 284B to the first core unit 89A and the second guiding unit 286B. In the example of the second embodiment, the first guiding portion 286A and the second guiding portion 286B include optical components such as a mirror and a lens. Specifically, as shown in FIG. 8, the first guiding unit 286A is configured to guide the laser beam from the first laser oscillator 284A to be incident on the first core unit 89A. The second guiding unit 286B is configured to guide the laser beam from the second laser oscillator 284B so as to enter the second core unit 89B. Even in this configuration, the laser light incident on the transmission unit 88 is guided to the processing head 82 by the transmission unit 88 and is emitted from the processing head 82. Also in this example, the laser light emitted from the processing head 82 through the first core portion 89A is the first laser light having a relatively large spot diameter, and passes from the processing head 82 through the second core portion 89B. The emitted laser light is the second laser light having a relatively small spot diameter. The laser beam irradiation device 280 has a configuration capable of emitting the first laser beam and the second laser beam at the same time.

2-2. Laser Welding Method Next, a laser welding method according to the second embodiment will be described.
Also in the laser welding method according to the present embodiment, the same arrangement process as in the first embodiment is performed, and the welding object W is arranged in the same arrangement as in FIGS. Also in this example, the first opposing surface 10B of the first metal member 10 and the second opposing surface 20A of the second metal member 20 are opposed to each other, and the first metal member 10 is placed on the second metal member 20 and stacked. Hold in the state. Also in this example, the first metal member so that the plate thickness direction of both metal parts (the first metal member 10 and the second metal member 20) configured in a plate shape is the overlapping direction, and the overlapping direction is the vertical vertical direction. 10 and the 2nd metal member 20 are arrange | positioned, and are hold | maintained by the holding part (mounting table etc.) which is not shown in figure.

  After performing such an arrangement process, an irradiation process is performed. In the irradiation step, laser light (specifically, toward the upper surface 10A (surface opposite to the first facing surface 10B in the thickness direction) of the first metal member 10 arranged in the arrangement step as shown in FIG. (1st laser beam and 2nd laser beam) are irradiated, and the fusion | melting part 30 which extends from the 1st metal member 10 to the 2nd metal member 20 in an overlapping direction is formed.

  In the irradiation step, the first irradiation operation and the second irradiation operation are performed by the laser beam irradiation apparatus 280 shown in FIG. As described above, the laser beam irradiation device 280 can irradiate the processing head 82 with the first laser beam having a relatively large beam diameter and the second laser beam having a relatively small beam diameter. In the first irradiation operation, the first laser beam is irradiated from the machining head 82 along the predetermined axis L, and the first laser beam is incident on the surface (irradiation surface) of the welding target W with the first spot diameter. Let In the second irradiation operation, the second laser light is irradiated from the machining head 82 along the axis L, and the second laser light is incident on the surface (irradiation surface) of the welding target W with the second spot diameter.

  FIG. 9 (A) relates to the laser welding method according to the present embodiment, conceptually showing a laser light irradiation region at each timing on the upper surface 10A of the first metal member 10, and FIG. The on / off period of the first irradiation operation, the on / off period of the second irradiation operation, the output of the first laser light, and the output of the second laser light are shown. In the example of FIG. 9A, as the irradiation range of the first laser beam on the surface of the first metal member 10, the range at time t1 is indicated by reference symbol S1a, and the range at time t3 is indicated by reference symbol S1b. The range at time t4 is indicated by reference symbol S1c, and the range at time t7 is indicated by reference symbol S1d. Further, as the irradiation range of the second laser light on the surface of the first metal member 10, the range at time t2 is indicated by S2a, the range at time t5 is indicated by symbol S2b, and the range at time t6 is indicated. Indicated by reference numeral S2c. The ranges S1a, S1b, S2a, and S2b are indicated by solid lines, but the other ranges are indicated by two-dot chain lines.

  In the example of FIG. 9, the period Ta for performing the first irradiation operation is periodically set with the period T and the period Tb for performing the second irradiation operation is also periodically set with the period T under the control of the control device 70. Specifically, the first period Ta1 in which only the first irradiation operation of the first irradiation operation and the second irradiation operation is performed and the second period Tb2 in which only the second irradiation operation is performed are alternately switched, and the first period In each of the third period Tb3 from the end of Ta1 to the start of the second period Tb2, and the fourth period Tb4 from the end of the second period Tb2 to the start of the next first period Ta1. The first irradiation operation and the second irradiation operation are performed in parallel. Then, in at least a part of the periods Tb3 and Tb4 in which the first irradiation operation and the second irradiation operation are performed in parallel, the output of the second laser beam is from the output of the second laser beam when the second laser beam is in the second period Tb2. Is also set small. In the example of FIG. 9B, the period from the start timing of the period Ta to the end timing of the period Tb that starts during the period Ta is one unit irradiation process period. , Which overlaps the period of each subsequent unit irradiation step. For example, in FIG. 9B, the period from time t1 to time t5 is one unit irradiation process period, and the subsequent unit irradiation process period starts from time t4. Some of these periods overlap. In the example of FIG. 9, unit irradiation is performed while overlapping a part of the period of the second irradiation operation in the unit irradiation process performed first and a part of the period of the first irradiation operation in the unit irradiation process performed immediately thereafter. The process is repeated.

  Also in this configuration, the control device 70 periodically applies a first control signal (a signal for instructing the first irradiation operation) to the laser light irradiation device 280 with a period T, and the laser light irradiation device 280 has a period T. In each set period Ta, the first laser beam is irradiated continuously or intermittently in a short cycle sufficiently shorter than the cycle T. Also in this example, the length of the period Ta and the output of the first laser beam are such that the first melting part 31 is formed only in the vicinity of the second facing surface 20A of the second metal member 20 as shown in FIG. To the extent that the first melted portion 31 is not formed on the second metal member 20. In other words, the length of the period Ta and the output of the first laser beam in the period Ta (predetermined high level) so that the size of the gap between the first facing surface 10B and the second facing surface 20A is reduced. Is set. Even in this configuration, the moving device 90 performs an operation of moving the machining head 82 in the “moving direction” in accordance with an instruction from the control device 70, and the laser is moved when the moving device 90 performs such a moving operation. The light irradiation device 280 periodically performs the first irradiation operation described above. Since such control is performed, each time the first irradiation operation is performed, the irradiation position of the first laser light moves in the “movement direction” on the upper surface 10A shown in FIG. 4, and as shown in FIG. The first melting part 31 is sequentially formed along the “movement direction”.

  Further, as shown in FIG. 9, the control device 70 irradiates laser light in each period Tb that is set periodically (each period Tb2 in which the first irradiation operation pauses in each period and periods Tb3 and Tb4 before and after that). A second control signal (signal for instructing the second irradiation operation) is given to the device 80. The laser beam irradiation device 80 performs the second irradiation operation in each period Tb in accordance with the second control signal.

  In the example of FIG. 9A as well, the spot diameter (first spot diameter) of the first laser light is larger than the spot diameter (second spot diameter) of the second laser light, and irradiation of the first laser light is performed. When the second irradiation operation is started when the operation continues and the processing head 82 is moving in the moving direction and the second laser light is irradiated from the processing head 82, the second laser light is emitted from the latest first laser beam. The first melting portion 31 formed by the irradiation operation (that is, the first melting portion 31 formed by the first irradiation operation continuing at the start time of the second irradiation operation) is irradiated, and the second laser light The irradiation position moves in the “movement direction” within the region of the first melting portion 31. For example, when the second irradiation operation is started at time t2 during execution of the first irradiation operation started at time t1, the second laser light irradiated immediately after the start of the second irradiation operation is being executed. The first melting portion 31 (range from the range S1a to the range S1b) formed by the first irradiation operation is irradiated, and the irradiation position of the second laser beam is the position of the first melting portion 31. In the region, the movement is made along the “movement direction” from the range S2a to the range S2b. Thus, by performing 2nd irradiation operation | movement, the 2nd fusion | melting part 32 straddling the 1st metal member 10 and the 2nd metal member 20 is formed in order so that a "movement direction" may be followed like FIG.6 (B). be able to. In this configuration as well, the second melting part 32 is formed in the region of the first melting part 31 on the irradiation surface, and is the second in the thickness direction (overlapping direction) of the first metal member 10 and the second metal member 20. It is a melting part extending to the metal member 20.

  Further, in the example of FIG. 9B, the output of the second laser light is gradually reduced below the output in the second period Tb2 while performing the first irradiation operation and the second irradiation operation in parallel in the third period Tb3. The second irradiation operation is performed so as to increase. Further, in the fourth period Tb4, the second irradiation is performed so that the output of the second laser light is gradually decreased below the output in the second period Tb2 while the first irradiation operation and the second irradiation operation are performed in parallel. It is operating.

  Also in the example of FIG. 9, the second irradiation operation is performed so that the irradiation range of the second laser light in each period partially overlaps the irradiation range of the second laser light in the previous period. . For example, the irradiation region (range S2b) of the second laser light at the time point (time t5) when the second irradiation operation ends in a certain cycle (cycle from time t2 to time t5), and the second irradiation in the next cycle. Since the irradiation region (range S2c) of the second laser light at the time point when the operation starts (time t6) is overlapped, the welding object W is not welded even if the second irradiation operation is performed periodically. The 2nd fusion | melting part 32 can be formed continuously along a moving direction.

2-3. Action / Effect In the laser welding method according to the present embodiment, in the irradiation step, the first period Ta1 in which only the first irradiation operation among the first irradiation operation and the second irradiation operation is performed and the second irradiation operation only in the second period are performed. The period Ta2 is alternately performed, and the first period Ta1 is started after the third period Ta3 from the end of the first period Ta1 to the start of the second period Ta2 and the end of the second period Ta2. The first irradiation operation and the second irradiation operation are performed in parallel during the fourth period Ta4. In this way, since the first irradiation operation and the second irradiation operation can be performed in parallel during a part of the period (the third period Tb3 and the fourth period Tb4), the first irradiation operation and the second irradiation are performed. The execution cycle of the operation can be easily shortened, and the increase in tact time can be further suppressed.

  Further, in the irradiation step, the output of the second laser light is changed to the second period in at least a part of the period (the third period Tb3 and the fourth period Tb4) in which the first irradiation operation and the second irradiation operation are performed in parallel. It is made smaller than the output of the 2nd laser beam at this time. In this way, the first irradiation operation and the second irradiation operation can be performed in parallel, and the first laser beam and the second laser beam are excessively emitted due to irradiation at the same time. Melting can be suppressed.

  In the irradiation process, the first irradiation operation and the second irradiation operation are performed in parallel in both the third period Tb3 and the fourth period Tb4. It becomes easier to shorten the execution cycle, and the tact time can be further suppressed. In addition, in the third period Tb3, the output of the second laser beam is gradually increased, and in the fourth period Tb4, the output of the second laser beam is gradually decreased. In the period Tb4, the output is suppressed as the time is later. In the third period Tb3, the earlier the timing, the greater the concern about the thermal effect due to the first irradiation operation, and the fourth period Tb4, the slower the timing, the greater the concern about the thermal effect due to the first irradiation operation. If this is done, the effect of mitigating thermal effects can be further enhanced.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention. Further, various features of the above-described embodiments and the embodiments described below may be combined in any way as long as they are not inconsistent.

  In the laser welding method according to the second embodiment, the first irradiation operation and the second irradiation operation are performed in parallel in both the third period Tb3 and the fourth period Tb4. The first irradiation operation and the second irradiation operation may be performed in parallel only in one of the periods Tb3 and the fourth period Tb4.

  In the above-described embodiment, in the first melting part 31, the irradiation range of the second laser light in each cycle and the irradiation range of the second laser light in the previous cycle are partially overlapped. It is not limited to this example. For example, in the example of FIG. 10, in the irradiation process, the first irradiation operation and the second irradiation operation are periodically performed, and the second laser light is periodically irradiated with the period T. The second irradiation operation is performed so as to separate the irradiation range of the second laser light in the unit irradiation step performed first and the irradiation range of the second laser light in the unit irradiation step performed immediately thereafter. Yes. FIG. 10 conceptually shows an example in which a part of FIG. 5 is changed, and conceptually shows the laser light irradiation region at each timing on the upper surface 10A of the first metal member 10, and also shows the first irradiation operation. An on / off period and an on / off period of the second irradiation operation are conceptually shown. In this example, as the irradiation range of the first laser beam on the surface of the first metal member 10, the range at time t1 is indicated by reference symbol S1a, the range at time t2 is indicated by reference symbol S1b, and time t4 The range at time t is indicated by symbol S1c, and the range at time t5 is indicated by symbol S1d. Further, as the irradiation range of the second laser light on the surface of the first metal member 10, the range at time t2 is indicated by S2a, the range at time t3 is indicated by reference sign S2b, and the range at time t5 is indicated. The range at time t6 is indicated by reference numeral S2c, and the range at time t6 is indicated by reference numeral S2d. In the example of FIG. 10, the second irradiation operation is performed between time t2 and time t3 in a certain cycle, and the irradiation range of the second laser light at that time is in the range from range S2a to range S2b. In the next cycle, the second irradiation operation is performed between time t5 and time t6, and the irradiation range of the second laser light at that time is in the range from range S2c to range S2d. The second irradiation operation is performed so that the irradiation range in the previous cycle (range S2a to range S2b) and the irradiation range in the subsequent cycle (range S2c to range S2d) do not overlap. As described above, if the irradiation range of the second laser light in each cycle is separated from the irradiation range of the second laser light in the previous cycle, the time during which the second irradiation operation is performed is further shortened. 2 It becomes easy to form a melted part over a wider range.

  In the above-described embodiment, the example in which both the first metal member 10 and the second metal member 20 are configured by flat metal plates has been described, but the present invention is not limited to this example. For example, the curved metal plate may be sufficient as the 1st metal member and the 2nd metal member. Alternatively, the second metal member may be configured as a cylindrical shape, and the first metal member may be configured as a curved metal plate that is stacked on the outer peripheral surface of the cylindrical metal portion. The first metal member may be configured in a cylindrical shape that fits outside the second metal member. In any case, laser welding may be performed by the above-described method on the overlapping portion of the first metal member and the second metal member.

  In the embodiment described above, an example in which the moving direction is a linear direction has been described, but the moving direction may be a curved direction.

  In the above-described embodiment, an example is shown in which the spot shapes of the first laser beam and the second laser beam (the outer edge shape of the laser beam when the laser beam is cut at a cutting plane orthogonal to the laser beam) are circular. It may be on a polygon such as a quadrangle, or may be another shape such as an ellipse.

DESCRIPTION OF SYMBOLS 10 ... 1st metal member 10A ... Upper surface 10B ... 1st opposing surface 20 ... 2nd metal member 20A ... 2nd opposing surface 30 ... Melting part 31 ... 1st melting part 32 ... 2nd melting part 80,280 ... Laser beam irradiation apparatus

Claims (8)

An arrangement step of arranging a first opposing surface of the first metal member and a second opposing surface of the second metal member facing each other and placing the first metal member on the second metal member;
In the overlapping direction of the first metal member and the second metal member by irradiating laser light toward the upper surface opposite to the first opposing surface of the first metal member arranged in the arrangement step An irradiation step of forming a melted portion extending from the first metal member to the second metal member;
A laser welding method comprising:
The irradiation step includes
Irradiating a first laser beam on the upper surface, thereby forming a first irradiation operation that forms a first molten portion that covers the entire first metal member in the overlapping direction;
The irradiation position of the second laser beam is predetermined while irradiating the second laser beam with a spot diameter smaller than that of the first laser beam in the region of the first melted part formed by the first irradiation operation. A second irradiation operation for forming the second molten portion extending to the second metal member in the overlapping direction so as to follow the moving direction by moving in the moving direction of
A unit irradiation process consisting of:
The unit irradiation step is performed first so as to start the first irradiation operation in the unit irradiation step performed immediately after the first irradiation operation in the unit irradiation step performed first is completed. The first laser beam in the unit irradiation step that is repeated first is repeated so as to start the second irradiation operation in the unit irradiation step that is performed immediately after the second irradiation operation in the unit irradiation step is completed. By shifting the irradiation position of the first laser beam in the unit irradiation step performed immediately after the irradiation position along the moving direction, the melting portion formed by the unit irradiation step is moved along the moving direction. Laser welding method of forming sequentially. The laser welding method according to claim 1, wherein in the irradiation step, the first irradiation operation and the second irradiation operation are performed by the same laser beam irradiation apparatus. In the irradiation step, the first irradiation operation and the second irradiation operation are periodically performed, and the unit irradiation performed immediately after the irradiation range of the second laser light in the unit irradiation step performed first. 3. The laser welding method according to claim 1, wherein the second irradiation operation is performed so as to partially overlap an irradiation range of the second laser light in a process. In the irradiation step, the first irradiation operation and the second irradiation operation are periodically performed, and the unit irradiation performed immediately after the irradiation range of the second laser light in the unit irradiation step performed first. 3. The laser welding method according to claim 1, wherein the second irradiation operation is performed so as to separate the irradiation range of the second laser light in a step. In the irradiation step, the second irradiation operation is started at the end of the first irradiation operation, and the first irradiation operation and the second irradiation operation are started at the end of the second irradiation operation. The laser welding method according to any one of claims 1 to 4, wherein the irradiation operation is switched alternately. In the irradiation step, a first period in which only the first irradiation operation of the first irradiation operation and the second irradiation operation is performed and a second period in which only the second irradiation operation is performed are alternately performed, At least one of a third period from the end of one period to the start of the second period, or a fourth period from the end of the second period to the start of the first period The laser welding method according to any one of claims 1 to 4, wherein the first irradiation operation and the second irradiation operation are performed in parallel during a period. In the irradiation step, the output of the second laser beam is the second laser beam during the second period in at least a part of the period in which the first irradiation operation and the second irradiation operation are performed in parallel. Smaller than the output of.
The laser welding method according to claim 6. In the irradiation step,
In the third period, the second irradiation is performed so that the first irradiation operation and the second irradiation operation are performed in parallel and the output of the second laser light is gradually increased below the output in the second period. Perform the action
In the fourth period, the first irradiation operation and the second irradiation operation are performed in parallel, and the output of the second laser light is gradually decreased below the output in the second period. The laser welding method according to claim 7, wherein two irradiation operations are performed.

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