JP2022182279A - Laser welding method, laser welding device, and electric apparatus - Google Patents

Abstract

To obtain improved new laser welding method, laser welding device, and electric apparatus each of which enables, for example, further shortening of an exposure section of a core wire of which the coating has been removed for welding.SOLUTION: A laser welding method, for example, performs laser welding of a first end of a core wire exposed from a coating at an end portion in a first direction that is a longitudinal direction of a first conducting wire, and a second end of the core wire exposed from a coating at an end portion in a first direction of a second conducting wire. The method comprises: a step in which the first end and the second end are arranged in such a manner that the first and the second ends extend in the first direction and are adjacent to each other in a second direction crossing the first direction; a step in which at least one of the first end and the second is irradiated with laser beam during a time less than 0.2 [sec] while being swept in a third direction crossing the first direction, thereby forming a molten pool spanned between the first end and the second end; and a step in which the molten pool is solidified.SELECTED DRAWING: Figure 5

Description

The present invention relates to a laser welding method, a laser welding device, and an electrical device.

There is known a method of laser welding a portion of a conducting wire such as a rectangular wire from which the covering is removed and the core wire is exposed (for example, Patent Document 1).

JP 2020-142283 A

In this type of welding, a longer length of coating may be removed at the weld location to reduce the effect of the heat generated in the weld on the coating. In this case, the longer the exposed section of the core wire from which the coating is removed, the more likely it is that a short circuit will occur, or that the size of the electrical device having the conductor wire will increase.

Therefore, one of the objects of the present invention is, for example, an improved new laser welding method and laser welding apparatus that makes it possible to shorten the exposed section of the core wire whose coating has been removed for welding. , and obtaining electrical equipment.

In the laser welding method of the present invention, for example, a first conductor having a core wire made of a metal material and a coating surrounding the core wire is exposed from the coating at the end in the first direction in the longitudinal direction of the core wire. a first end, and a second end of the core wire exposed from the coating at the end in the first direction of a second conductor having a core wire made of a metal material and a coating surrounding the core wire, A laser welding method for laser welding, the step of arranging the first end and the second end so as to be adjacent to each other in a second direction extending in a first direction and intersecting the first direction; By irradiating at least one of the first end portion and the second end portion with a laser beam for less than 0.2 [sec] while sweeping in a third direction that intersects the first direction, the forming a molten pool spanning between one end and the second end; and solidifying the molten pool.

In the laser welding method, an exposed length in the first direction of at least one of the first end portion and the second end portion may be 10 mm or less.

In the laser welding method, exposed lengths of both the first end portion and the second end portion in the first direction may be 10 [mm] or less.

In the laser welding method, in the step of forming the molten pool, the laser beam may be linearly swept.

In the laser welding method, the third direction may intersect the second direction.

In the laser welding method, the step of forming the molten pool may include the step of sweeping the laser beam multiple times.

In the laser welding method, the step of sweeping the laser beam a plurality of times includes a first sweeping step of sweeping the laser beam and a unit of a virtual plane intersecting the first direction rather than the first sweeping step and a second sweeping step of sweeping the laser beam with a low power density per area.

In the laser welding method, the sweep speed of the laser light in the second sweep step may be higher than the sweep speed of the laser light in the first sweep step.

In the laser welding method, power of the laser light in the second sweep step may be lower than power of the laser light in the first sweep step.

In the laser welding method, the step of sweeping the laser beam a plurality of times includes a third sweeping step of sweeping the laser beam at a predetermined intensity and a predetermined sweep speed, and after the third sweeping step, the sweeping the laser light at an intensity lower than a predetermined intensity, sweeping the laser light at a sweep speed faster than the predetermined sweep speed, and sweeping the laser light at an intensity lower than the predetermined intensity and faster than the predetermined sweep speed and a fourth sweeping step of performing at least one of the sweeps of the laser light in velocity.

In the laser welding method, the step of forming the molten pool includes sweeping the laser beam along the third direction and sweeping the laser beam along the fourth direction opposite to the third direction. and sweeping the laser light.

In the laser welding method, the step of forming the molten pool includes sweeping the laser light over the first end, sweeping the laser light over the second end, may include

In the laser welding method, in the step of forming the molten pool, the laser light may include a plurality of beams.

In the laser welding method, in the step of forming the molten pool, the laser light may include a plurality of beams having different wavelengths.

In the laser welding method, the plurality of beams may be spaced apart in the sweep direction of the laser beam.

In the laser welding method, in the step of forming the molten pool, the laser light includes a first portion including at least one beam with a first power density and a second power different from the first power density. a second portion containing at least one beam of density.

In the laser welding method, in the step of forming the molten pool, the first portion and the second portion may be separated from each other in the sweep direction of the laser beam.

In the laser welding method, the second portion may surround the first portion.

In the laser welding method, a ratio of the power of the laser beam at the first portion to the power of the laser beam at the second portion may be 3/7 or more and 7/3 or less.

In the laser welding method, the sweep speed of the laser beam may be 150 [mm/sec] or more.

In the laser welding method, in the step of forming the molten pool, a plurality of laser beams may be irradiated in parallel.

In the laser welding method, the step of forming the molten pool is a step of irradiating the first end with at least one laser beam and simultaneously irradiating the second end with at least one other laser beam. may include

In the laser welding method, in the step of forming the molten pool, an inert gas is directed toward at least one of the first end portion, the second end portion, the molten pool, and the coating. may be supplied.

In the laser welding method, the core wire may be made of a copper-based metal or an aluminum-based metal.

In the laser welding method, the coating may contain polyetheretherketone.

The laser welding method of the present invention includes, for example, a first exposed portion exposed from the coating in the core wire of a first conductor having a core wire made of a metal material and a coating surrounding the core wire, and a first exposed portion made of the metal material A laser welding method for laser welding a second exposed portion exposed from the coating in the core wire of a second conductor having a core wire and a coating surrounding the core wire, wherein the first exposed portion and the second A step of irradiating at least one of the exposed portions with a laser beam for a time of less than 0.2 [sec] while sweeping to form a molten pool extending over the first exposed portion and the second exposed portion; and solidifying the molten pool.

The laser welding device of the present invention includes, for example, a first exposed portion exposed from the coating in the core wire of a first conductor having a core wire made of a metal material and a coating surrounding the core wire, and a first exposed portion made of the metal material A laser welding device for laser welding a second exposed portion exposed from the coating in the core wire of a second conductor having a core wire and a coating surrounding the core wire, the laser welding device comprising: a light source that outputs a laser beam; and an optical head for outputting the laser beam from a light source, wherein the optical head sweeps the laser beam to at least one of the first exposed portion and the second exposed portion for 0.2 [sec]. Irradiating for less than a period of time forms a weld pool across the first exposed portion and the second exposed portion.

The electrical device of the present invention includes, for example, a first conductor having a core wire made of a metal material and a coating surrounding the core wire, and a second conductor having a core wire made of a metal material and a coating surrounding the core wire. and a weld extending between a first exposed portion of the first conductor exposed from the coating and a second exposed portion of the second conductor exposed from the coating, wherein the first exposed portion and At least one of the second exposed portions has an exposed length of 10 mm or less between the welded portion and the coating.

According to the present invention, for example, a novel improved laser welding method, laser welding apparatus, which reduces the thermal effect on the coating and allows a shorter exposed section of the core wire from which the coating is removed, and you can get electrical equipment.

FIG. 1 is an exemplary schematic configuration diagram of a laser welding device according to the first embodiment. FIG. 2 is an exemplary and schematic side view of an object before welding in the laser welding method of the embodiment. FIG. 3 is an exemplary and schematic side view of an object after welding in the laser welding method of the embodiment. FIG. 4 is an exemplary and schematic perspective view of a rectangular wire including a member as an object of the laser welding method of the embodiment. FIG. 5 is a flow chart showing an example of the procedure of the laser welding method according to the embodiment. FIG. 6 is a schematic plan view showing an example of a beam pattern of laser light in the laser welding device of the first embodiment. FIG. 7 is a schematic plan view showing an example of a sweep path of laser light in the laser welding method of the embodiment. FIG. 8 is a graph showing an example of the state of the coating according to the irradiation time of the laser beam and the exposed length of the core wire in the laser welding method of the embodiment. FIG. 9 is an X-ray transmission image of a sample of an object on which a well-welded welded portion was obtained by the laser welding method of the embodiment, viewed from the side. FIG. 10 is a schematic plan view showing another example of a beam pattern of laser light in the laser welding device of the embodiment. FIG. 11 is a schematic plan view showing another example of the sweep path of laser light in the laser welding method of the embodiment. FIG. 12 is an exemplary schematic configuration diagram of the laser welding device of the second embodiment. FIG. 13 is a schematic plan view showing an example of a beam pattern of laser light in the laser welding device of the second embodiment.

Exemplary embodiments and variations of the invention are disclosed below. The configurations of the embodiments and modifications shown below, and the actions and results (effects) brought about by the configurations are examples. The present invention can be realized by configurations other than those disclosed in the following embodiments and modifications. Moreover, according to the present invention, at least one of various effects (including derivative effects) obtained by the configuration can be obtained.

The following embodiments and variations have similar components. In the following description, the same reference numerals are given to the same constituent elements, and overlapping explanations may be omitted.

In each figure, the X direction is indicated by an arrow X, the Y direction is indicated by an arrow Y, and the Z direction is indicated by an arrow Z. The X-, Y-, and Z-directions intersect and are orthogonal to each other. The Z direction is the direction in which the plurality of members that form the object W extend. Although the Z direction is substantially vertically upward, it may be tilted with respect to the vertically upward direction.

In this specification, ordinal numbers are given for convenience in order to distinguish directions, processes, members, parts, physical quantities, etc., and do not indicate priority or order.

[First embodiment]
[Overview of Laser Welding Equipment and Laser Welding]
FIG. 1 is a diagram showing a schematic configuration of a laser welding device 100 of the first embodiment. As shown in FIG. 1, the laser welding device 100 includes a laser device 110, an optical head 120, an optical fiber 130, a driving mechanism 140, a sensor 150, and a control device 200.

The laser welding device 100 irradiates a laser beam L onto the surface of an object W to be laser-welded. The object W is partially melted by the energy of the laser beam L, cooled, and solidified, thereby welding the object W. The object W has a plurality of members, and by laser welding, a molten pool extending over the plurality of members is formed, and the plurality of members are joined by solidifying the molten pool.

A plurality of members to be the object W can be made of, for example, a copper-based metal material such as copper or a copper alloy, an aluminum-based metal material such as aluminum or an aluminum alloy, or the like. A plurality of members may be made of the same metal material, or may be made of different metal materials. Note that the plurality of members that become the object W are conductors.

The laser device 110 includes a laser oscillator, and is configured, for example, to output a single-mode laser beam with a power of several kW. For example, the laser device 110 may include a plurality of semiconductor laser elements inside, and may be configured to output multimode laser light with a power of several kW as the total output of the plurality of semiconductor laser elements. The laser device 110 may also include various laser light sources such as fiber lasers, YAG lasers, disk lasers, and the like. Also, the laser device 110 outputs laser light with a wavelength of 400 [nm] or more and 1200 [nm] or less, for example.

The laser device 110 outputs laser light with a wavelength of, for example, 800 [nm] or more and 1200 [nm] or less. A laser oscillator included in the laser device 110 is an example of a light source.

Further, the laser device 110 may output a continuous wave of laser light, or may output a pulse of laser light.

Controller 200 may control the operation of laser device 110 . For example, the control device 200 can control the laser device 110 to output laser light, stop outputting laser light, or change the output intensity.

An optical fiber 130 optically connects the laser device 110 and the optical head 120 . In other words, the optical fiber 130 guides the laser light output from the laser device 110 to the optical head 120 . If the laser device 110 outputs single-mode laser light, the optical fiber 130 is configured to propagate the single-mode laser light. In this case, the ^M2 beam quality of single-mode laser light is set to 1.3 or less. The ^M2 beam quality may also be referred to as the M2 factor.

The optical head 120 is an optical device that transmits and outputs laser light from the laser device 110 and irradiates the target W with the laser light. The optical head 120 has a collimator lens 121 , a condenser lens 122 , a mirror 124 , a DOE 125 and a galvanometer scanner 126 . Collimating lens 121, condenser lens 122, mirror 124, DOE 125, and galvanometer scanner 126 may also be referred to as optics.

The collimating lens 121 collimates the laser light input via the optical fiber 130 . The collimated laser light becomes parallel light.

The mirror 124 reflects the laser light collimated by the collimating lens 121 and directs it toward the galvanometer scanner 126 .

Galvanometer scanner 126 has a plurality of mirrors 126a and 126b. By changing the angles of the plurality of mirrors 126a and 126b, it is possible to switch the emission direction of the laser light L from the optical head 120, thereby changing the irradiation position of the laser light L on the surface of the object W. . The angles of the mirrors 126a and 126b are respectively changed by motors (not shown) controlled by the controller 200, for example. By changing the emission direction of the laser light L while irradiating the laser light L, the laser light L can be swept over the surface of the object W. FIG.

The condensing lens 122 condenses the laser light as parallel light coming from the galvanometer scanner 126 and irradiates the object W with the laser light L (output light).

A DOE 125 (DOE: diffractive optical element) shapes a beam of laser light that has been collimated by a collimator lens 121 . DOE 125 is an example of a beam shaper.

The drive mechanism 140 changes the relative position of the optical head 120 with respect to the object W. FIG. The drive mechanism 140 includes, for example, a rotation mechanism such as a motor, a reduction mechanism that reduces the rotation output of the rotation mechanism, a motion conversion mechanism that converts the rotation reduced by the reduction mechanism into direct motion, and the like. The control device 200 can control the driving mechanism 140 so that the relative position of the optical head 120 with respect to the object W in the X, Y and Z directions is changed. The drive mechanism 140 can change (switch) the object W to be laser-welded among the plurality of objects W supported by the support mechanism (not shown). Further, the driving mechanism 140 can change the irradiation position of the laser beam L on the object W. FIG. Further, the drive mechanism 140 can be used to change the irradiation point as the irradiation direction of the laser beam L with respect to the object W is changed. Further, the driving mechanism 140 can change the irradiation position while the surface of the object W is being irradiated with the laser light L. FIG. That is, the drive mechanism 140 can sweep the laser light L on the surface of the object W. FIG.

FIG. 2 is a side view showing a state before the object W is welded. As shown in FIG. 2, the object W has two members 20 (21, 22). Both of the two members 20 are made of metal material.

Both of the two members 20 extend in the Z direction and have ends 20a (21a, 22a) in the Z direction. The end portion 20a spreads across the Z direction. That is, the end portion 20a extends in the X direction and in the Y direction. The Z direction is an example of a first direction. The end 21a is an example of a first end, and the end 22a is an example of a second end.

The two members 20 are arranged so as to be adjacent to each other in the X direction that intersects the Z direction and to line up in the X direction. A gap g is formed between the side surfaces 21a1 and 22a1 facing each other in the X direction. The X direction is an example of the second direction.

The ends 21a and 22a may each be slightly inclined with respect to the Z direction, and may be arranged so that the gap g becomes smaller toward the Z direction. That is, the two members 20 may be at least partially in contact. That is, the size of the gap g is 0 or more. In the example of FIG. 2, the ends 21a and 22a are aligned in the X direction and are positioned at the same position in the Z direction. It may be shifted in the Z direction.

Further, when welding the object W, that is, the two members 20, the optical head 120 irradiates the laser beam L toward the end portion 20a. The irradiation direction of the laser light L is the direction opposite to the Z direction or the direction inclined with respect to the direction opposite to the Z direction.

Also, the laser light L may be applied to both the end portion 21a and the end portion 22a, or may be applied to only one of the end portion 21a and the end portion 22a.

FIG. 3 is a side view showing a state in which a welded portion 23 (molten pool) is formed on the object W. As shown in FIG. By irradiating one of the two ends 20a with the laser beam L, the member 20 melts at each of the ends 20a as shown in FIG. A welded portion 23 is formed at . The welded portion 23 is formed by cooling and solidifying a molten pool formed in a state of being bridged between the two ends 20a. A molten pool, which is a metal material having fluidity, has a shape that bulges in the Z direction due to surface tension. Along with this, the welded portion 23 formed by solidifying the molten pool also has a bulging shape in the Z direction. The weld 23 mechanically connects the two members 21 and 22 . Moreover, since the two members 21 and 22 are made of conductive metal, the welded portion 23 electrically connects the two members 21 and 22 .

The sensor 150 (see FIG. 1) is, for example, a camera that captures an image of a molten pool formed on the object W. As shown in FIG. In this case, sensor 150 is an example of a motion sensor. The control device 200 can acquire the movement (change over time) of the surface of the molten pool from the images acquired by the sensor 150 .

Also, the sensor 150 may be a thermal camera capable of detecting the temperature of the molten pool. In this case, sensor 150 is an example of a temperature sensor. The control device 200 can acquire the temperature of the molten pool from the temperature image acquired by the sensor 150 .

4 is a perspective view of conductor 10 including member 20. FIG. The member 20 is, for example, the core wire (inner conductor) of the conducting wire 10 as shown in FIG. The conducting wire 10 has a member 20 and a covering 30 of the member 20 . In this embodiment, the conducting wire 10 is a rectangular wire as an example.

The member 20 is made of a conductive metal material. The shape of the cross section of the member 20 perpendicular to the extending direction is substantially rectangular.

Coating 30 also surrounds member 20 . The coating 30 has insulating properties and is made of, for example, enamel or a synthetic resin material. The coating 30 may have only an enamel layer composed of polyimide or polyamideimide, or may have an enamel layer and an extruded resin layer surrounding the enamel layer. Also, the synthetic resin material is polyetheretherketone as an example, but is not limited to this.

The laser welding apparatus 100 is applied to the laser welding of the end portions 20a exposed from the coating 30 of the member 20 as the core wire of the conducting wire 10 as described above. In this case, prior to welding, the coating 30 is removed near the ends of the two conductors 10 in the extending direction. The length E of the exposed section 20b of the member 20 is the length in the longitudinal direction (Z direction) from the end 20a of the member 20 to the end 30a of the coating 30, and is an example of the exposed length. The exposed section 20b provided at the end 21a is an example of a first exposed section, and the exposed section 20b provided at the end 22a is an example of a second exposed section. Also, the two conductors 10 are an example of a first conductor and a second conductor.

As shown in FIG. 2, the laser welding apparatus 100 welds the exposed section 20b including the end portions 20a of the two members 20 arranged adjacent to each other while facing the same direction (extending direction).

The conducting wire 10 may constitute a segment coil (winding) provided in a rotating electric machine as an electric device. The laser welding method by the laser welding apparatus 100 of this embodiment can be applied to welding the ends of adjacent segment coils set on the stator core. That is, the object W shown in FIG. 3 may be part of an electrical device.

Moreover, the conducting wire 10 is not limited to a rectangular wire, and may be another conducting wire such as a round wire.

Further, in welding, in this embodiment, the gas G is supplied from the gas nozzle 127 toward at least one of the end portions 20a (21a, 22a), the molten pool, and the coating 30 . Gas G is an inert gas and may also be referred to as an assist gas. The inert gas here refers to a gas that is chemically stable and resistant to reaction, and includes, for example, nitrogen, argon, carbon dioxide, or mixed gases thereof. By supplying the gas G, it is possible to suppress the oxidation of the end portion 20a and the molten pool, appropriately cool the end portion 20a, the molten pool, the coating 30, etc., and prevent the coating 30 from deteriorating due to the heat generated during welding. Deterioration can be suppressed.

FIG. 5 is a flow chart showing the procedure of the laser welding method. As shown in FIG. 5, first, the covering 30 of the two conductors 10 as the objects W is partially removed to form the exposed section 20b of the member 20 (S1).

Next, an object W is set (S2). In S2, as shown in FIG. 2, the ends 20a (21a, 22a) are arranged so as to extend in the Z direction and be adjacent to each other in the X direction.

Next, a molten pool is formed by irradiating at least one of the two ends 20a (21a, 22a) with the laser beam L (S3). In S3, the laser light L is irradiated while being swept in a direction crossing the Z direction.

Next, the molten pool is cooled and solidified to form a welded portion 23 extending between the two ends 20a, that is, between the two conductors 10, as shown in FIG. 3 (S4). In S4, the molten pool may be naturally cooled or forcedly cooled.

[Laser light beam pattern]
FIG. 6 is a plan view showing an example of the beam pattern of the laser light L output from the optical head 120 of this embodiment. In FIG. 6, the beam B1 is indicated by a solid line and the beam B2 is indicated by a dashed line.

As shown in FIG. 6, the laser beam L includes a plurality of beams B1 and B2, and includes at least one beam B1 and at least one beam B2. The power densities of the beams B1, B2 may differ from each other. Such beams B 1 , B 2 can be formed and positioned by DOE 125 . By exchanging the DOE 125, the shape, arrangement, power density, etc. of the beams B1 and B2 can be changed.

Each of the beams B1 and B2 has, for example, a Gaussian-shaped power distribution in the radial direction of the cross section perpendicular to the optical axis direction of the beam. However, the power distributions of beam B1 and beam B2 are not limited to Gaussian shapes. In FIG. 6, the diameters of the circles representing the beams B1 and B2 are the beam diameters of the beams B1 and B2. The beam diameter of each of the beams B1 and B2 can be defined as the diameter of the area including the peak of the beam and having an intensity of 1/e ² or more of the peak intensity. Also, although not shown, in the case of a non-circular beam, the beam diameter can be defined as the length of the region where the intensity is 1/e2 ^or more of the peak intensity in the direction perpendicular to the sweep direction SD in plan view.

Of the laser light L, the portion containing the beam B1 is an example of the first portion, and the portion containing the beam B2 is an example of the second portion. In the example of FIG. 6, the laser light L includes one beam B1 forming the first portion and a plurality of beams B2 forming the second portion.

The second portion having beam B2 is circumferentially formed and arranged to surround the first portion having beam B1. Also, the first portion and the second portion are separated in the sweep direction SD.

In the example of FIG. 6, the width D1 in the sweep direction SD of the first portion is the diameter of the beam B1, which is circular, and is defined as the diameter of the region of intensity greater than or equal to 1/e ² of the peak intensity. Also, the width D2 in the sweep direction SD of the second portion is defined as the distance between the centers of the two beams B2 that are most apart in the direction orthogonal to the sweep direction SD in plan view.

[Sweep path]
FIG. 7 is an explanatory diagram (plan view) showing an example of the sweep route R1 of the laser light L at the ends 21a and 22a. In this embodiment, the laser beam L is linearly swept in the order of sweep paths R11, R12, R13, and R14 in the direction intersecting the Z direction. The sweep paths R11 and R12 are paths along which the laser light L is swept over the end portion 21a, and the sweep paths R13 and R14 are paths along which the laser light L is swept over the end portion 22a. Thus, the step (S3) of irradiating the end portions 21a and 22a with the laser beam L to form the molten pool on the end portions 21a and 22a includes the step of sweeping the laser beam L multiple times.

As shown in FIG. 7, each of the end portions 21a and 22a has a rectangular shape in a plan view. It has a rectangular shape that is relatively short in the X-direction and relatively long in the Y-direction. In this case, the Y direction can be referred to as the width direction or the longitudinal direction of the cross section, and the X direction can be referred to as the thickness direction or the lateral direction of the cross section. In addition, in the example of FIG. 7, as an example, the end portion 21a and the end portion 22a have the same shape, but the present invention is not limited to this.

In the example of FIG. 7, the laser light L is divided into, for example, an area A1 closer to the end 22a than the center C1 of the end 21a in the X direction and an area closer to the end 21a than the center C2 of the end 22a in the X direction. A2 and . However, the position to be swept, that is, the irradiation area is not limited to areas A1 and A2.

In sweep paths R11 and R13, the laser light L is swept in the Y direction, and in sweep paths R12 and R14, the laser light L is swept in the opposite direction to the Y direction. The Y direction and the direction opposite to the Y direction are examples of the third direction. Also, the Y direction is an example of a fourth direction.

[Experimental result]
The inventors conducted an experiment of welding the ends 21a and 22a by sweeping the beam-shaped laser light L shown in FIG. 6 while irradiating it along the path shown in FIG. In the experiment, the irradiation time of the laser light L and the length E of the exposed section 20b (exposed length, see FIG. 4) were determined under the conditions under which the influence of the heat generated in welding on the coating 30 can be reduced. I found Furthermore, the inventors have found the conditions under which good welding can be performed with respect to the output ratio of the laser light L between the first portion and the second portion, the width D2 of the second portion, and the sweep speed. In these experiments, the coating 30 was made of polyetheretherketone and made of a copper-based metal with a length in the X direction of about 1.5 mm and a length in the Y direction of about 3.1 mm. The end portions 21a and 22a of the member 20 are irradiated with a laser beam L having a wavelength of 1070 [nm], and the spot diameter of the beam B1 at the end portions 21a and 22a in a state where no molten pool is formed is It was set to about 200 [μm]. In this experiment, the irradiation time of the laser beam L was set to 0.06 [sec] or more, and the ratio (output ratio) of the output of the first portion to the output of the second portion of the laser beam L was set to 5/5. Further, the output of the laser device is adjusted in the range of 3 [kW] to 6 [kW] so that the welding of the ends 21a and 22a is completed by the irradiation of the laser light L for each irradiation time.

The inventors investigated the state of the coating 30 according to the irradiation time of the laser light L and the length E of the exposed section 20b of the member 20 as the core wire at the end 20a. FIG. 8 is a graph showing an example of the experimental results, in which the vertical axis represents the exposure length [mm] corresponding to the peeling length of the coating, and the horizontal axis represents the laser irradiation time [sec]. In FIG. 8, regarding the state of the coating 30, the best state in which almost no deterioration due to heat is observed is indicated by ⊙, and the excellent state in which required performance such as insulation is obtained although slight deterioration due to heat is observed is indicated by ◯. A defective state in which deterioration occurs and required performance such as insulation cannot be obtained was evaluated as x.

As shown in FIG. 8, by setting the irradiation time of the laser beam L to less than 0.2 [sec], preferably less than 0.1 [sec], the length E of the exposed section 20b is reduced to 6 [mm]. ] or more and 10 [mm] or less, or even 6 [mm] or more and 8 [mm] or less, the state of the coating 30 can be maintained in the best state or excellent state. . In this way, either one or both of the length E of the exposed section 20b of the member 21 and the member 22 is 6 [mm] or more and 10 [mm] or less, further 6 [mm] or more and 8 [mm] ] Also as described below, welding can be performed while reducing the influence of deterioration of the coating 30 due to heat.

表１に示されるように、第二部位の幅Ｄ２は、第一部位の幅Ｄ１の５倍以下であるのが好ましく、２倍を超え４倍以下であるのがより好ましく、３.６倍以下であるのがより一層好ましいことが判明した。また、出力比は、３／７以上であるのが好ましく、７／３以下であるのがより好ましく、４／６以上６／４以下であるのがより一層好ましいことが判明した。 In addition, the inventors conducted an experiment using the ratio (output ratio) of the output of the first portion to the output of the second portion of the laser beam L and the width D2 (see FIG. 6) of the second portion as parameters. We have found the conditions under which the welding can be performed. Table 1 shows an example of the experimental results. In Table 1, the best state in which the number of spatters generated in welding (steps S3 and S4) is 25 or less is indicated by ⊚, and the excellent state ∘ in which the number of spatters exceeds 25 and is 60 or less.

As shown in Table 1, the width D2 of the second portion is preferably 5 times or less the width D1 of the first portion, more preferably more than 2 times and 4 times or less, and 3.6 times It has been found that the following is even more preferable. It was also found that the output ratio is preferably 3/7 or more, more preferably 7/3 or less, and even more preferably 4/6 or more and 6/4 or less.

表２に示されるように、掃引速度は、溶接時の過剰な入熱を抑制しスパッタの発生を低減する観点から、１５０［ｍｍ／ｓｅｃ］以上であるのが好ましく、２００［ｍｍ／ｓｅｃ］以上であるのがより好ましいことが判明した。また、出力比は、３／７を超えるのが好ましく、７／３以下であるのがより好ましく、４／６以上６／４以下であるのがより一層好ましいことが判明した。 Furthermore, the inventors conducted an experiment using the output ratio and the sweep speed of the laser beam L as parameters, and found the conditions under which good welding can be performed. Table 2 shows an example of the experimental results. In Table 2, the best condition in which the number of spatters generated by welding is 25 or less is marked with ⊚, the excellent condition with more than 25 and 60 or less is marked with ◯, and the good condition with more than 50 is marked with Δ.

As shown in Table 2, the sweep speed is preferably 150 [mm/sec] or more, and 200 [mm/sec], from the viewpoint of suppressing excessive heat input during welding and reducing spatter generation. It has been found that the above is more preferable. Also, it was found that the output ratio is preferably greater than 3/7, more preferably 7/3 or less, and even more preferably 4/6 or more and 6/4 or less.

Further, according to the experimental research of the inventors, in the step of forming a molten pool (S3), when performing a plurality of sweeps, a virtual By making the power density per unit area of a plane (for example, a virtual plane that substantially overlaps the end surface of the end portion 20a) lower than the power density per unit area of the virtual plane in the previous sweeping step, more sputtering or blowing can be achieved. It was found that a better weld condition was obtained with fewer weld defects such as holes. The previous sweeping process is an example of the first sweeping process, and the subsequent sweeping process is an example of the second sweeping process.

FIG. 9 is an X-ray transmission image of a sample of the object W in which a welded portion 23 in a good welded state is obtained, viewed from the side. The material of the members 21, 22 (20) constituting the object W is oxygen-free copper, and in the welding of the object W, the irradiation time of the laser beam L is 0.064 [sec], and the output is 6 [kW]. ], the output ratio was 5/5 (=1), and the sweep speed was 200 [mm/sec]. As is clear from FIG. 9, there were very few blowholes in the sample.

The higher the sweep speed, the lower the power density per unit area of the virtual plane, and the lower the power of the laser light L, the lower the power density per unit area. Therefore, in the subsequent sweep process, the sweep speed is made higher than that in the previous sweep process, the power of the laser light L is made lower than that in the previous sweep process, or the sweep speed is made higher than that in the previous sweep process. By making the power of the laser light L lower than that in the previous step, the power density per unit area of the virtual plane is made lower in the subsequent sweeping step than in the previous sweeping step, resulting in a better welding state. can be obtained. More specifically, for example, in the step of forming a molten pool (S3), when sweeping is performed more than a predetermined number of times (for example, three times), the sweep speed is made faster than the sweeping before the predetermined number of times. sweep, a sweep that reduces the power of the laser light L more than during the sweep before the predetermined number of times, and a sweep speed that is faster than during the sweep before the predetermined number of times and a laser beam that is faster than during the sweep before the predetermined number of times. By executing at least one sweep in which the power of the light L is reduced, a better welding state can be obtained.

As described above, according to the laser welding method and the laser welding apparatus 100 of the present embodiment, in the step of forming the molten pool (S3), the end portion 21a (first end portion) and the end portion 22a (second end), while sweeping in the Y direction that intersects the Z direction (first direction) or in the direction opposite to the Y direction (third direction) for a time of less than 0.2 [sec] By irradiating, it is possible to form a molten pool spanning between the ends 21a and 22a.

Such irradiation of the laser light L can suppress deterioration of the coating 30 due to heat generated during welding. In addition, in the conducting wire 10, the length E of the exposed section 20b for welding can be relatively short, for example, 10 [mm] or less. It is possible to obtain the effect of suppressing an increase in the size of an electric device including the conducting wire 10 having the member 20 and the coating 30 while making it difficult to occur.

In addition, in this embodiment, as described above, the covering 30 of the conducting wire 10 having the relatively short length E of the exposed section 20b can be made of a material containing polyetheretherketone as a synthetic resin material. That is, according to the present embodiment, as the coating 30 of the lead wire 10 of the electric device, the coating 30 containing polyether ether ketone, which has a higher insulation property than polyimide or the like, that is, has a higher withstand voltage, can be used. , the breakdown voltage is higher, the short circuit is less likely to occur, and a more compact electric device can be easily constructed.

Further, in the present embodiment, the first portion containing the beam B1 of the laser light L and the second portion containing the beam B2 are separated from each other at least in the sweep direction SD. According to the present embodiment, for example, before the first portion of the laser beam L including the beam B1 forms the molten pool in the keyhole state, the second portion of the laser beam L including the beam B2 forms the edge portion 21a. , 22a can be preliminarily heated, thereby suppressing a rapid temperature rise of the ends 21a, 22a, so that the weld pool is more stabilized, and thus welding such as spatter and blowholes can be prevented. It is possible to suppress the occurrence of defects.

[Another example of beam shape (modification)]
FIG. 10 is a plan view showing another example of the beam pattern of the laser light L. FIG. In the example of FIG. 10, the second portion including beam B2 does not have a circumferential (annular) shape. However, in this example as well, the second portion containing the beam B2 is spaced apart from the first portion of the laser light L containing the beam B1 in the sweep direction SD and in the direction opposite to the sweep direction SD. With the beam pattern as shown in FIG. 10, the object W can be preliminarily heated by the second portion of the laser beam L before the first portion of the laser beam L is irradiated. You can get the same effect as Further, according to the example of FIG. 10, even when the laser beam L is swept in the direction opposite to the sweep direction SD in FIG. 10 without rotating the optical head 120 around the Z-axis, preliminary heating The effect of suppressing welding defects can be obtained. Also, as in the example of FIG. 6, when the second portion has an annular shape, the optical head 120 is swept in an arbitrary direction intersecting the Z direction without rotating around the Z axis. In some cases, the preliminary heating has the effect of suppressing poor welding. That is, if at least a part of the second portion including the beam B2 exists ahead in the sweep direction with respect to the first portion including the beam B1, the effect of suppressing welding defects is obtained by the preliminary heating.

[Another example of sweep path (modification)]
FIG. 11 is an explanatory diagram (plan view) showing an example different from FIG. 7 of the sweep paths R1 and R2 of the laser light L at the ends 21a and 22a. In this example, a molten pool is formed by simultaneously irradiating laser light L at a plurality of locations (for example, two locations) on the end portion 20a. Specifically, in parallel with sweeping the laser light L along the sweep route R11 (R1) on the end 21a, the laser light L is swept along the sweep route R21 (R2) on the end 22a, and then In parallel with sweeping the laser light L along the sweep route R12 (R1) on the end portion 21a, the laser light L is swept along the sweep route R22 (R2) on the end portion 22a.

According to such a method, the process of forming the molten pool can be completed in a shorter time, so deterioration of the coating 30 due to heat generated during welding can be further suppressed. It should be noted that such irradiation of the laser light L to a plurality of locations may be performed by a plurality of optical heads 120, or a plurality of laser beams L may be branched from one optical head 120 for irradiation.

[Second embodiment]
FIG. 12 is a diagram showing a schematic configuration of a laser welding device 100A of the second embodiment. As shown in FIG. 12, the laser welding device 100A has a plurality of laser devices 111, 112 (110).

The laser device 111 is the same as that of the first embodiment, and outputs first laser light with a wavelength of 800 [nm] or more and 1200 [nm] or less, for example. Laser device 111 may also be referred to as a first laser device. A laser oscillator included in the laser device 111 is a light source and can also be referred to as a first laser oscillator.

On the other hand, the laser device 112 outputs second laser light with a wavelength of 300 [nm] or more and 600 [nm] or less, for example. Laser device 112 may also be referred to as a second laser device. A laser oscillator included in the laser device 112 is a light source and can also be referred to as a second laser oscillator.

For copper-based materials and aluminum-based materials, the second laser light has a higher absorptance and a lower reflectance than the first laser light.

Further, the laser devices 111 and 112 may respectively output continuous waves of laser light or may output pulses of laser light.

The filter 123 is a high-pass filter that transmits the first laser beam and reflects the second laser beam without transmitting it. The first laser light from mirror 124 is transmitted through filter 123 and directed to galvanometer scanner 126 . On the other hand, the second laser beam from the collimating lens 121 is reflected by the filter 123 and directed toward the galvanometer scanner 126 . Filter 123 may also be referred to as an optical component.

Although not shown, the optical head 120A may have a DOE 125 that shapes the beam of the first laser beam or the second laser beam as appropriate.

FIG. 13 is a plan view showing an example of the beam pattern of the laser light L output from the optical head 120A of this embodiment. As shown in FIG. 6, the laser light L includes multiple beams B1 and B2. The beam B1 is a beam of the first laser beam and constitutes the first portion of the laser beam L. As shown in FIG. Also, the beam B2 is a beam of the second laser beam and constitutes the second portion of the laser beam L. As shown in FIG. The beam B2 has a high absorption rate by the object W and forms a thermally conductive molten pool. According to this embodiment, sweeping in the sweep direction SD forms a softer heat-conducting weld pool before a keyhole-type weld pool is formed by the beam B1, so that the ends 21a, It is possible to suppress a rapid temperature rise of 22a and, in turn, suppress welding defects such as spatter and blowholes.

The pattern of the beams B1 and B2 having different wavelengths is not limited to the example in FIG. It may be configured so that the second part by the beam B2 reaches before it reaches. That is, if at least a part of the second portion including the beam B2 exists ahead in the sweep direction with respect to the first portion including the beam B1, the effect of suppressing welding defects is obtained by the preliminary heating.

Although the embodiments and modifications of the present invention have been illustrated above, the above-described embodiments and modifications are examples and are not intended to limit the scope of the invention. The above embodiments and modifications can be implemented in various other forms, and various omissions, replacements, combinations, and modifications can be made without departing from the scope of the invention. In addition, specifications such as each configuration and shape (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) may be changed as appropriate. can be implemented.

For example, an object may include three or more members. Also, the plurality of members included in the target object may not be the same member. Moreover, the target object is not limited to a plurality of members arranged side by side or butted against each other, and may be a plurality of superimposed members.

Further, the exposed section of at least one conductor among the plurality of conductors may be provided at an intermediate position in the longitudinal direction of the conductor.

Further, when irradiating the laser beam, known wobbling, weaving, output modulation, or the like may be performed to adjust the surface area of the molten pool.

10... Lead wire (first lead wire, second lead wire)
20... Member 20a... End 20b... Exposed section (first exposed part, second exposed part)
21... Member (core wire)
21a ... end (first end)
21a1... Side surface 22... Member (core wire)
22a... end (second end)
22a1... Side surface 23... Welded portion (molten pool)
30... Coating 30a... Edges 100, 100A... Laser welding device 110, 111, 112... Laser device (light source)
Reference Signs List 120, 120A Optical head 121 Collimating lens 122 Collecting lens 123 Filter 124 Mirror 125 DOE
126 Galvanometer scanners 126a, 126b Mirror 127 Gas nozzle 130 Optical fiber 140 Drive mechanism 150 Sensor 200 Control devices A1, A2 Area B1 Beam (first part)
B2... beam (second part)
C1, C2...Center D1...Width D2...Width E...Length (exposed length)
g Gap G Gas L Laser light R1, R11, R12, R13, R14, R2, R21, R22 Sweep path SD Sweep direction W Object X Direction (second direction)
Y... direction (third direction, fourth direction)
Z direction (first direction)

Claims (28)

A first end of the core wire exposed from the coating at the end in the first direction that is the longitudinal direction of the first conductor having a core wire made of a metal material and a coating surrounding the core wire, and a first end of the core wire made of a metal material. A laser welding method for laser welding a second end of the core wire exposed from the coating at the end in the first direction of a second conductor having a core wire and a coating surrounding the core wire,
arranging the first end and the second end so as to be adjacent to each other in a second direction that intersects the first direction;
By irradiating at least one of the first end and the second end with a laser beam for less than 0.2 [sec] while sweeping in a third direction that intersects the first direction, forming a molten pool spanning between a first end and the second end;
solidifying the molten pool;
A laser welding method comprising: The laser welding method according to claim 1, wherein the exposed length in the first direction of at least one of the first end and the second end is 10 mm or less. The laser welding method according to claim 1, wherein exposed lengths of both the first end portion and the second end portion in the first direction are 10 [mm] or less. The laser welding method according to any one of claims 1 to 3, wherein in the step of forming the molten pool, the laser beam is linearly swept. The laser welding method according to any one of claims 1 to 4, wherein said third direction crosses said second direction. The laser welding method according to any one of claims 1 to 5, wherein the step of forming the molten pool includes the step of sweeping the laser beam multiple times. The step of sweeping the laser beam a plurality of times includes a first sweeping step of sweeping the laser beam and a state in which the power density per unit area of the virtual plane intersecting the first direction is lower than that in the first sweeping step. The laser welding method according to claim 6, comprising a second sweeping step of sweeping the laser beam. The laser welding method according to claim 7, wherein the sweep speed of said laser light in said second sweep step is higher than the sweep speed of said laser light in said first sweep step. The laser welding method according to claim 7 or 8, wherein the power of said laser light in said second sweeping step is lower than the power of said laser light in said first sweeping step. The step of sweeping the laser light a plurality of times comprises: a third sweeping step of sweeping the laser light at a predetermined intensity and a predetermined sweep speed; sweeping the laser light, sweeping the laser light at a sweep speed faster than the predetermined sweep speed, and sweeping the laser light at an intensity lower than the predetermined intensity and at a sweep speed faster than the predetermined sweep speed and a fourth sweep step of performing at least one of the sweeps. The step of forming the molten pool includes sweeping the laser beam along the third direction, sweeping the laser beam along a fourth direction opposite to the third direction, and The laser welding method according to any one of claims 1 to 6, comprising The step of forming the molten pool includes sweeping the laser light over the first end and sweeping the laser light over the second end. The laser welding method according to any one of them. The laser welding method according to any one of claims 1 to 12, wherein in the step of forming the molten pool, the laser light includes a plurality of beams. 14. The laser welding method according to claim 13, wherein in the step of forming the molten pool, the laser light includes a plurality of beams having different wavelengths. The laser welding method according to claim 13 or 14, wherein said plurality of beams are spaced apart in the sweep direction of said laser light. In the step of forming the molten pool, the laser light includes a first portion including at least one beam with a first power density and a second portion including at least one beam with a second power density different from the first power density. The laser welding method according to any one of claims 13 to 15, comprising two parts. The laser welding method according to claim 16, wherein in the step of forming the molten pool, the first portion and the second portion are separated from each other in the sweep direction of the laser beam. 17. The laser welding method according to claim 16, wherein said second portion surrounds said first portion. 19. The laser welding method according to claim 18, wherein the ratio of the power of said laser light at said first portion to the power of said laser light at said second portion is 3/7 or more and 7/3 or less. The laser welding method according to any one of claims 1 to 19, wherein the sweep speed of said laser beam is 150 [mm/sec] or more. The laser welding method according to any one of claims 1 to 20, wherein in the step of forming said molten pool, a plurality of laser beams are irradiated in parallel. The step of forming the molten pool includes the step of irradiating the first end with at least one laser beam and simultaneously irradiating the second end with at least one other laser beam. laser welding method. In the step of forming the molten pool, an inert gas is supplied toward at least one of the first end, the second end, the molten pool, and the coating. The laser welding method according to any one of them. The laser welding method according to any one of claims 1 to 23, wherein the core wire is made of copper-based metal or aluminum-based metal. A laser welding method according to any preceding claim, wherein the coating comprises polyetheretherketone. A first exposed portion exposed from the coating in the core wire of a first conductor having a core wire made of a metallic material and a coating surrounding the core wire, and a core wire made of a metal material and the coating surrounding the core wire A laser welding method for laser welding a second exposed portion exposed from the coating in the core wire of the second conductor having
By irradiating at least one of the first exposed portion and the second exposed portion with a sweeping laser beam for a time of less than 0.2 [sec], the first exposed portion and the second exposed portion are formed. forming a molten pool spanning
solidifying the molten pool;
A laser welding method comprising: A first exposed portion exposed from the coating in the core wire of a first conductor having a core wire made of a metallic material and a coating surrounding the core wire, and a core wire made of a metal material and the coating surrounding the core wire A laser welding device for laser welding a second exposed portion exposed from the coating in the core wire of the second conductor having
a light source that outputs laser light;
an optical head that outputs the laser beam from the light source;
with
The optical head sweeps and irradiates at least one of the first exposed portion and the second exposed portion with a laser beam for a time of less than 0.2 [sec], whereby the first exposed portion and the A laser welding device for forming a molten pool across the second exposed portion. a first conductor wire having a core wire made of a metal material and a coating surrounding the core wire;
a second conductor having a core wire made of a metal material and a coating surrounding the core wire;
a weld spanning between a first exposed portion of the first conductor exposed from the coating and a second exposed portion of the second conductor exposed from the coating;
with
The electrical device, wherein the exposed length between the welded portion and the coating is 10 mm or less in at least one of the first exposed portion and the second exposed portion.

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