Welding method and laser device

Abstract

[Problem] To provide a welding method and a laser device that do not require a trimming step for flattening the tip side of a rectangular line in a stator manufacturing process. [Solution] A welding method in which a first member and a second member, each of which has a convex tip end side, are brought into contact with each other, the tip ends of which face a laser device, and welding is performed using a laser beam, the welding method being characterized by comprising: a first step in which the laser beam is irradiated to a position of the tip end of the first member, said position being close to the contact surface, to form a first fusion region; and 2, irradiating the laser to the position, close to the butt joint face, of the front end of the second component to form a second fusion area.

Description

Technical Field

[0001] The present invention relates to a welding method for metal welding using a laser. Background Art

[0002] Laser welding using a laser is used as one of the techniques for metal welding. Compared with other welding techniques, laser welding can weld a workpiece with high-density energy through a condenser lens, has high welding quality, and is suitable for fine welding.

[0003] In recent years, such laser welding has been used for manufacturing stators for electric motors assembled in hybrid vehicles or electric vehicles. A stator is composed of a stator core and a plurality of coil segments installed in slots of the stator core, and the ends of the corresponding coil segments are joined to each other by laser welding. Generally, each coil segment uses a rectangular wire, and its welding surface is as fine as several square millimeters, so it is suitable for laser welding.

[0004] In the manufacturing process of a stator, first, a rectangular wire is inserted into a slot of the stator. At this time, in order to prevent the front end of the rectangular wire from getting stuck, the front end of the rectangular wire is cut into a tapered shape and then inserted. Then, after inserting and aligning each rectangular wire, a "trimming process" for flattening the front end is performed to make the heights of the respective rectangular wires uniform and to stabilize the quality of the subsequent welding process (see Patent Document 1).

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2015-43676 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, the above-described trimming process is the main cause of the apparatus becoming large and affecting the production cycle time of the production line. In addition, the trimmed scrap material is discarded, resulting in a problem of low material utilization rate.

[0010] Therefore, the present invention has been completed in view of the above problems, and an object thereof is to provide a welding method and a laser device that do not require a trimming process.

[0011] Means for Solving the Problems

[0012] In order to solve the above problems, the present invention provides a welding method, which butt-joins a first component and a second component with convex shapes on the front end sides, makes the front ends face a laser device, and performs welding using the laser. The method is characterized by including: a first step of irradiating the laser on a position of the front end of the first component close to the butt-joint surface to form a first fusion zone; and a second step of irradiating the laser on a position of the front end of the second component close to the butt-joint surface to form a second fusion zone.

[0013] Advantages of the Invention

[0014] According to the present invention, since it is possible to weld the first component and the second component with convex shapes on the front end sides, the trimming process in the stator manufacturing process is not required.

[0015] Brief Description of the Drawings

[0016] Figure 1 is a flowchart showing a method for manufacturing an existing stator coil.

[0017] Figure 2 is a flowchart showing a method for manufacturing a stator coil in the present embodiment.

[0018] Figure 3 is an external view showing the overall structure of the laser device 1.

[0019] Figure 4 is a block diagram showing the functional structure of the laser device 1.

[0020] Figure 5 is a diagram showing the structure of the compound galvanometer type scanning galvanometer 10.

[0021] Figure 6 is a diagram for explaining the function of the focus shift unit 6.

[0022] Figure 7 is a diagram for explaining the function of the galvanometer type scanning galvanometer unit 8.

[0023] Figure 8 is a block diagram showing the functional structure of the image processing unit 9.

[0024] Figure 9 is a block diagram showing the functional structure of the control PC 12.

[0025] Figure 10 is a perspective view showing a schematic structure of the stator 50 as a workpiece W.

[0026] Figure 11 (a), (b) are diagrams for explaining the shape of the rectangular wire 52 in the present embodiment.

[0027] Figure 12It is a flowchart for explaining the welding process of the laser device 1, continued Figure 13 。

[0028] Figure 13 It is a flowchart for explaining the welding process of the laser device 1, continued Figure 12 。

[0029] Figure 14 (a) and (b) are diagrams for explaining the focal position in the welding process of the laser device 1.

[0030] Figure 15 (a) is a diagram showing the trajectory of laser irradiation in the first step of the present embodiment, Figure 15 (b) is a diagram showing the trajectory of laser irradiation in the second step of the present embodiment.

[0031] Figure 16 (a) and (b) are schematic diagrams showing the shape change of the welding surface of the workpiece W.

[0032] Figure 17 (a) and (b) are diagrams for explaining the shape of the rectangular wire 52 in the modified example.

[0033] Figure 18 It is a block diagram showing the functional structure of the structure of the laser device 1a in the modified example.

[0034] Figure 19 (a) is a diagram showing the trajectory of laser irradiation in the first step of the modified example. (b) is a diagram showing the trajectory of laser irradiation in the second step of the modified example. Detailed implementation mode

[0035] <Overview>

[0036] One welding method of the present embodiment is a welding method in which a first component and a second component with a convex shape on the front end side are butt-jointed, the front end is opposed to the laser device, and welding is performed using a laser. The method is characterized by including: a first step of irradiating the laser at a position near the butt-joint surface of the front end of the first component to form a first fusion zone; and a second step of irradiating the laser at a position near the butt-joint surface of the front end of the second component to form a second fusion zone.

[0037] In another welding method of the present embodiment, the first component and the second component are rectangular wires constituting a stator coil, and the convex shape on the front end side is a mountain-shaped roof shape having a first inclined surface formed at the front end portion of the rectangular wire and a second inclined surface formed non-parallel to the first inclined surface. In the first step and the second step, the laser is irradiated on one inclined surface located near the butt-joint surface among the first inclined surface and the second inclined surface.

[0038] In another welding method of the present embodiment, it is characterized in that in the first step, the inclined surface of the first component near the butt joint surface is irradiated reciprocally in a substantially straight line to form the first fusion zone, and in the second step, the inclined surface of the second component near the butt joint surface is irradiated reciprocally in a substantially straight line to form the second fusion zone.

[0039] In another welding method of the present embodiment, it is characterized in that the laser irradiation in the first step and the laser irradiation in the second step are alternately repeated.

[0040] In another welding method of the present embodiment, it is characterized in that the laser irradiation in the first step and the laser irradiation in the second step are alternately repeated until the first fusion zone and the second fusion zone are combined.

[0041] In another welding method of the present embodiment, it is characterized in that the laser irradiation in the first step and the laser irradiation in the second step are alternately repeated until the first fusion zone and the second fusion zone are combined to form a molten sphere of a predetermined size.

[0042] In another welding method of the present embodiment, it is characterized in that there is a gap between the first component and the second component, and the welding method alternately repeats the laser irradiation in the first step and the second step until the first fusion zone and the second fusion zone enter the gap.

[0043] Another welding method of the present embodiment is characterized by further including a jump step. During the alternate repetition of the laser irradiation in the first step and the laser irradiation in the second step, after irradiating a rectangular line with laser, the laser irradiation position is moved to another rectangular line in a state where the laser irradiation is stopped.

[0044] In another welding method of the present embodiment, it is characterized in that in the first step, the laser is irradiated 1.5 times reciprocally in a substantially straight line on the inclined surface of the first component, and in the second step, the laser is irradiated 1.5 times reciprocally in a substantially straight line on the inclined surface of the second component.

[0045] Another welding method of the present embodiment is characterized by including: a photographing step of photographing the first component and the second component to be welded; and a control step of analyzing the image taken by the photographing step, obtaining the position information of the first component and the second component, and determining the laser irradiation position based on the obtained position information.

[0046] Another welding method according to this embodiment is characterized by including: an imaging step of imaging the first component and the second component to be welded; and a control step of analyzing the image captured in the imaging step, obtaining the height information of the first component and the second component, and determining the midpoint of the heights of the first component and the second component as the focal position based on the obtained height information.

[0047] In another welding method according to this embodiment, the laser is composed of a first laser and a second laser having different wavelengths from each other.

[0048] In another welding method according to this embodiment, the wavelength of the first laser is 300 to 600 nm.

[0049] In another welding method according to this embodiment, the wavelength of the second laser is 780 nm to 1100 nm.

[0050] In another welding method according to this embodiment, the output powers of the first laser and the second laser are 500 W to 3 kW.

[0051] In another welding method according to this embodiment, the diameter of the focused spot of the second laser is smaller than the diameter of the focused spot of the first laser.

[0052] In another welding method according to this embodiment, the diameter of the focused spot of the second laser is one-tenth or less of the diameter of the focused spot of the first laser.

[0053] In another welding method according to this embodiment, the diameter of the focused spot of the second laser is 10 μm to 100 μm.

[0054] In another welding method according to this embodiment, nitrogen is jetted onto the front end portion at a flow rate of 5 L / min to 100 L / min and an inclination angle with respect to the front end portion of 0 to 90° simultaneously with the irradiation of the laser or from before the irradiation to the end of the irradiation or for a longer time.

[0055] A laser device according to one aspect of the present embodiment is a laser device that butt-welds a first component and a second component with a convex shape at the front end side to weld the front end, and is characterized by comprising: an oscillator that oscillates a laser; a galvanometer scanning mirror unit that displaces the laser in an arbitrary direction and irradiates it; and a control unit that controls the oscillator and the galvanometer scanning mirror. The control unit controls the oscillator and the galvanometer scanning mirror to irradiate the laser at a position where the front end of the first component is close to the butt joint surface to form the first fusion zone, and irradiate the laser at a position where the front end of the second component is close to the butt joint surface to form the second fusion zone.

[0056] A laser device according to another aspect of the present embodiment is characterized by further comprising an image processing unit that images the first component and the second component to detect position information, and the control unit determines the irradiation position of the laser using the position information detected by the image processing unit.

[0057] <Embodiment>

[0058] Here, a laser device 1 according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The laser device 1 is a welding device that irradiates a workpiece W made of a material with high thermal conductivity with a laser and performs welding of the workpiece W by thermally converting the energy of the laser. As an example, the workpiece W is a stator coil assembled in an electric vehicle or the like.

[0059] Figure 1 It is a flowchart showing a conventional method for manufacturing a stator coil. In the conventional manufacturing method, before inserting a rectangular wire into a slot of a stator, in order to prevent the front end of the rectangular wire from getting stuck, the front end of the rectangular wire is cut into a conical shape (step S1). Then, each rectangular wire is inserted into the corresponding slot (step S2), and after alignment, in order to make the heights of the respective rectangular wires uniform and to stabilize the quality of the subsequent welding process, a trimming process for flattening the front end is performed (step S3). After that, the front ends of the corresponding rectangular wires are laser welded to each other (step S4).

[0060] On the other hand, Figure 2 It is a flowchart showing a method for manufacturing a stator coil when using the laser device of the present embodiment. In the present embodiment, first, as in the existing example, in order to prevent the front end of the rectangular wire from getting stuck when inserted into the slot, the front end of the rectangular wire is cut into a conical shape (step S11). Then, each rectangular wire is inserted into the corresponding slot and aligned (step S12). Next, in the present embodiment, the front ends of the corresponding rectangular wires are laser welded to each other in a state where the front ends of the rectangular wires are conical (step S13).

[0061] In this manner, in the present embodiment, the rectangular wire is not subjected to the trimming process of cutting it to be flat, and the rectangular wire with a sharp front end is irradiated with laser light. Even in such a case, a laser device and a welding method that can prevent the occurrence of spatter and achieve high-quality welding processing will be described in detail below.

[0062] Figure 3 FIG. 4 is an external view showing the structure of the laser device 1 of the present embodiment, Figure 4 and FIG. 5 is a schematic diagram showing the functional structure of the laser device 1.

[0063] As Figure 3 and Figure 4 shown, the laser device 1 includes the following components: a first oscillator 2 (blue semiconductor laser) that oscillates a first laser beam L1; a second oscillator 3 (IR fiber laser) that oscillates a second laser beam L2; a compound galvanometer type scanning galvanometer 10 that aligns the optical axes of the first laser beam L1 and the second laser beam L2 and displaces the irradiation positions of the first laser beam L1 and the second laser beam L2 on the workpiece W; an image processing unit 9 that captures an image of the workpiece W and analyzes the position information of each rectangular wire; a workpiece setting table 11 that mounts the workpiece W and can move the mounted workpiece W in three-dimensional directions (x, y, z) and in the rotational direction (θ) about the z-axis; a fixing jig 15 that is used to fix the workpiece W to the workpiece setting table 11; a control PC (personal computer) 12 that controls the entire laser device 1; a PLC (programmable logic controller) 13 that cooperates with the control PC 12 to control each device; a laser controller 14 that controls the operations of the first oscillator 2 and the second oscillator 3; and protection gas nozzles 19a and 19b that supply a protection gas such as nitrogen to the workpiece W (the description of the protection gas nozzles 19a and 19b is omitted in Figure 4 ).

[0064] In addition, the image processing unit 9 includes an illumination device 101, a camera device 102, and a controller 103, and the controller 103 is built into Figure 3 the control board 100. The control board 100 has a computer for controlling the laser device 1. Specifically, in addition to the controller 103 of the image processing unit 9, the PLC 13 and the laser controller 14 are also built in. In addition, the workpiece setting table 11 includes a base 11a, an x-axis stage 11x that is a mechanism for moving the workpiece W in the x-axis direction, a y-axis stage 11y that is a mechanism for moving the workpiece W in the y-axis direction, a θ-axis stage 11θ that is a mechanism for rotating the workpiece W about the z-axis, and a z-axis stage 11z that is a mechanism for relatively moving the workpiece W and the compound galvanometer type scanning galvanometer 10 in the z-axis direction.

[0065] (1) Regarding the laser

[0066] The first laser L1 and the second laser L2 oscillated from the first oscillator 2 and the second oscillator 3 are respectively transmitted through optical fibers and incident on the compound galvanometer type scanning mirror 10. Moreover, the first laser L1 and the second laser L2 are overlapped by the compound galvanometer type scanning mirror 10 in a manner that the optical axes coincide. After the overlapped first laser L1 and second laser L2 are reduced to a predetermined diameter, they are irradiated onto the workpiece W opposite thereto. In this way, in the laser device 1, the workpiece W is irradiated with two kinds of lasers, the first laser L1 and the second laser L2, for welding.

[0067] As the first laser L1, a blue semiconductor laser connected to a multimode optical fiber is used. The wavelength of the first laser L1 may be 300 to 600 nm, and a green laser may be used instead of the blue laser. In addition, the output power of the first laser L1 is preferably 500 W to 3 kW, and in this embodiment, it is set to 800 W as an example.

[0068] As the second laser L2, a near-infrared single-mode fiber laser with a wavelength of 780 nm to 1100 nm is used. That is, the wavelengths of the first laser L1 and the second laser L2 are different from each other, and the wavelength of the first laser L1 is shorter than that of the second laser L2. The output power of the second laser L2 is preferably 500 W to 3 kW, and in this embodiment, it is set to 2 kW as an example.

[0069] In this embodiment, the first laser L1 uses multimode, and the second laser L2 uses single mode. The second laser L2 is a spot with a smaller focused spot diameter than the first laser L1. Therefore, by using a single-mode fiber laser as the second oscillator 3, the second laser L2 with a small beam diameter and a high peak energy intensity can be effectively generated.

[0070] (2) Regarding the compound galvanometer type scanning mirror 10

[0071] Next, the details of the compound galvanometer type scanning mirror 10 will be described.

[0072] Figures 5 to 7 The shown compound galvanometer type scanning mirror includes: a beam combiner unit 4 that overlaps the first laser L1 and the second laser L2 supplied from the first oscillator 2 and the second oscillator 3 on the same optical axis; a focus shift unit 6 that is located downstream of the beam combiner unit 4 and adjusts the focal length of the lasers (the first laser L1 and the second laser L2) overlapped on the same optical axis; and a galvanometer type scanning mirror unit 8 that is located downstream of the focus shift unit 6 and displaces the direction of the optical axis of the lasers (the first laser L1 and the second laser L2) toward the workpiece W.

[0073] As Figure 5As shown, the beam combiner unit 4 has, for example: lenses (collimating lenses, etc.) 31 and 32 that collimate the lasers (first laser L1 and second laser L2) supplied from the first oscillator 2 and the second oscillator 3 into parallel light; and mirrors (including beam splitters, semi-transmissive semi-reflective mirrors, beam combiners, etc.) 33 and 34 required to align the optical axes of the respective lasers (first laser L1 and second laser L2) that pass through the lenses 31 and 32. Of course, the beam combiner unit 4 may also have optical elements, optical fibers, and others other than those described above. In addition, in the beam combiner unit 4, three or more lasers with different wavelengths may be overlapped.

[0074] As Figure 6 shown, the focus shift unit 6 has a lens (concave lens, particularly a double concave lens, etc.) 41 that enlarges the diameter of the lasers (first laser L1 and second laser L2) overlapped in the beam combiner unit 4, and lenses (a plurality of convex lenses, particularly plano-convex lenses that serve as collimating lenses or condenser lenses, etc.) 42 and 43 that reduce the diameter of the lasers (first laser L1 and second laser L2) that pass through the lens 41. Of course, the focus shift unit 6 may also have optical elements, optical fibers, and others other than those described above.

[0075] The focus shift unit 6 variably adjusts the focal length F of the lasers (first laser L1 and second laser L2) introduced from the beam combiner unit 4. Therefore, in Figure 6 the example shown, at least one of the lens (concave lens) 41 and / or the lens (convex lens) 42 is supported by a linear motor stage or other appropriate driving mechanism and can move forward and backward in the optical axis direction so that the distance (relative distance) D along the laser (first laser L1 and second laser L2) axis between the lens (concave lens) 41 and the lens (convex lens) 42 can be variably adjusted. In addition, the terminal lens (condenser lens) 43 may not move forward and backward in the optical axis direction.

[0076] As Figure 6 (a) shows, the narrower the distance D between the lens (concave lens) 41 and the lens (convex lens) 42, the longer the focal length F of the lasers (first laser L1 and second laser L2) that pass through the lenses 41, 42, and 43 of the focus shift unit 6. That is, the focus of the lasers (first laser L1 and second laser L2) deviates from the terminal lens 43 of the focus shift unit 6.

[0077] Conversely, as Figure 6 (b) shows, the larger the distance D between the lens (concave lens) 41 and the lens (convex lens) 42, the shorter the focal length F of the lasers (first laser L1 and second laser L2) that pass through the lenses 41, 42, and 43 of the focus shifter 6. That is, the focus of the lasers (first laser L1 and second laser L2) approaches the terminal lens 43 of the focus shift unit 6.

[0078] In addition, in the lenses 41, 42, and 43, as a general physical law, chromatic aberration (the refractive index of light depends on the wavelength of the light) inevitably occurs. Therefore, when irradiating the workpiece W with a laser that overlaps multiple lasers with different wavelengths, the irradiation position of a laser with a certain wavelength and the irradiation position of other lasers with different wavelengths that should overlap it shift on the workpiece W. Due to this shift, it may not be possible to obtain the desired laser processing or machining result. Therefore, in practice, by adjusting the position of the lenses 31 and / or the lens 32 through which the lasers (the first laser L1 and the second laser L2) output from the first oscillator 2 and the second oscillator 3 pass, the focal points of the first laser L1 and the second laser L2 to be overlapped are made to coincide.

[0079] As Figure 5 and Figure 7 shown, the galvanometer type scanning mirror unit 8 is a known component that rotates the reflecting mirrors 81 and 83 that reflect the lasers (the first laser L1 and the second laser L2) introduced from the focal point shift unit 6 via drive mechanisms 82 and 84 such as a servo motor and a stepping motor. In short, the galvanometer type scanning mirror unit 8 can displace the direction of the optical axis of the lasers (the first laser L1 and the second laser L2) reflected by the reflecting mirrors 81 and 83. The galvanometer type scanning mirror unit 8 in the present embodiment has an x-axis galvanometer type scanning mirror (drive mechanisms 82 and 84) that changes the optical axis of the lasers (the first laser L1 and the second laser L2) directed toward the workpiece W along the x-axis direction on the workpiece W and a y-axis galvanometer type scanning mirror (drive mechanisms 82 and 84) that changes the optical axis of the lasers (the first laser L1 and the second laser L2) along the y-axis direction on the workpiece W, and scans the first laser L1 and the second laser L2 on the workpiece W in the xy two-dimensional direction, thereby enabling two-dimensional control of the irradiation positions of the first laser L1 and the second laser L2 on the workpiece W.

[0080] As a feature of the composite galvanometer type scanning mirror 10 of the present embodiment, it can be cited that the adjustment of the focal length F by the focal point shift unit 6 and the displacement of the optical axis direction by the galvanometer type scanning mirror unit 8 are synchronized.

[0081] The closer the angle θ of the optical axis of the lasers (the first laser L1 and the second laser L2) passing through the reflecting mirrors 81 and 83 of the galvanometer type scanning mirror unit 8 with respect to the workpiece W is to perpendicular, the shorter the optical path length from the reflecting mirror 83 to the workpiece W. Therefore, the focal point shift unit 6 and the galvanometer type scanning mirror unit 8 are synchronously controlled so that the focal length F achieved by the focal point shift unit 6 becomes shorter as the angle θ of the laser (the first laser L1 and the second laser L2) axis with respect to the workpiece W approaches perpendicular (90°).

[0082] Conversely, the more the optical axes of the lasers (first laser L1, second laser L2) via the mirrors 81, 83 of the galvanometer scanning mirror unit 8 are inclined with respect to the vertical direction with respect to the angle θ of the workpiece W, the longer the optical path length from the mirror 83 to the workpiece W. Therefore, the focus shift unit 6 and the galvanometer scanning mirror unit 8 are synchronously controlled so that the focal length F achieved by the focus shift unit 6 becomes longer as the angle θ of the laser (first laser L1, second laser L2) axis with respect to the workpiece W inclines (away from 90°).

[0083] By the synchronous control of the lenses 41, 42 of the focus shift unit 6 and the mirrors 81, 83 of the galvanometer scanning mirror unit 8, it is possible to irradiate any part on the workpiece W with the first laser L1 and the second laser L2, and it is possible to reliably focus the first laser L1 and the second laser L2 on the desired processing object surface of the workpiece W.

[0084] Preferably, there is no lens (such as an fθ lens) through which the laser (first laser L1, second laser L2) passes between the mirrors 81, 83 of the galvanometer scanning mirror unit 8 and the workpiece W. Thereby, it is possible to reliably avoid the problem of chromatic aberration generated when the laser (first laser L1, second laser L2) in the optical axis direction operated by the galvanometer scanning mirror unit 8 passes through the lens. That is, there is no shift between the position where the laser (first laser L1) of a certain wavelength irradiates the workpiece W and the position where the overlapping laser (second laser L2) irradiates the workpiece W. Therefore, a desired laser processing or machining result can be obtained.

[0085] However, if the chromatic aberration only occurs to the extent that the shift of the irradiation positions of the respective lasers (first laser L1, second laser L2) can be ignored, it is okay to have a certain lens through which the laser (first laser L1, second laser L2) passes between the mirrors 81, 83 of the galvanometer scanning mirror unit 8 and the workpiece W.

[0086] In addition, the compound galvanometer scanning mirror used in the present embodiment is not limited to the structure described above. The lenses (biconcave lens) 41, the lens (collimating lens) 42, and the lens (condensing lens) 43, which are elements of the focus shift unit 6, are all located downstream of the mirrors 33, 34, which are elements of the beam combiner unit 4, but the arrangement of these optical elements (mirrors 33, 34, lens (biconcave lens) 41, lens (collimating lens) 42, lens (condensing lens) 43) is not limited to Figure 5 the arrangement shown.

[0087] (3) Regarding the image processing unit 9

[0088] In the welding of stator coils, in order to appropriately irradiate a rectangular wire of several millimeters with a laser, it is preferable to accurately measure the position of the rectangular wire. Therefore, in the laser device 1, the central position and height of a plurality of rectangular wires 52 with respect to the front end are measured by image analysis of the image processing unit 9.

[0089] As Figure 8 shown, the image processing unit 9 includes an illumination device 101 that irradiates the workpiece W with illumination light, an imaging device 102 that images the workpiece W in a state irradiated by the illumination device 101, and a controller 103 that uses the image data captured by the imaging device 102 to measure the central position and height of each rectangular wire 52 included in the workpiece W.

[0090] The illumination device 101 and the imaging device 102 are an illumination device and a 3D camera suitable for the fringe projection method. The illumination device 101 projects a plurality of stripe patterns from a plurality of different directions onto the workpiece W, and the imaging device 102 receives the reflected light through an image sensor such as a CMOS. The controller 103 generates a 3D image by analyzing the pattern changes of the projected light and the reflected light.

[0091] As Figure 8 shown, the controller 103 includes a memory 104 and a processor 105. A measurement program 111 is pre-stored in the memory 104. The processor 105 measures the central position and height of all the rectangular wires 52 included in the workpiece W by executing the measurement program 111, and generates a coordinate table 112 (CSV data) that records the measurement results for each pair to be welded. The processor 105 stores the generated coordinate table 112 in the memory 104.

[0092] (4) Regarding the control PC12

[0093] As Figure 9 shown, the control PC12 is composed of a control unit 201, a storage unit 202, an input unit 203, a communication unit 204, and a display unit 205.

[0094] Specifically, the control PC12 is a computer system having hardware resources such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), a display unit, a communication interface, and input devices such as a keyboard or a mouse. In welding processing using a galvanometer scanning mirror, the control PC is sometimes referred to as a "galvanometer PC".

[0095] The control unit 201 is composed of a CPU 211, a RAM 212 serving as a working memory, and the like.

[0096] The storage unit 202 is a so-called auxiliary storage device, which is composed of a non-volatile memory such as an HDD, an SSD, a ROM (read-only memory), or a flash memory.

[0097] Stored in the storage unit 202 are various data such as a computer program for controlling the laser device 1, various laser parameters input via the input unit 203, and machining graphic data used in welding processing.

[0098] The CPU 211 of the control unit 201 loads the computer program stored in the storage unit 202 into the RAM 212 serving as a working memory and executes it, thereby controlling the first oscillator 2, the second oscillator 3, the compound galvanometer type scanning galvanometer 10, the PLC 13, the laser controller 14, etc., and performing the welding process of the workpiece W. In addition, the laser parameters stored in the storage unit 202 are the laser output used by the first oscillator 2 and the second oscillator 3, the processing rate (laser irradiation time), the marking speed, the acceleration time, the deceleration time, etc.

[0099] The input unit 203 further includes an input device that accepts user operations by connecting a keyboard, a mouse, various switches, etc., and a device that inputs data through a removable recording medium such as a USB memory or an SD memory card. The data input via the input unit 203 is stored in the storage unit 202.

[0100] The communication unit 204 performs information communication with external devices (image processing unit 9, compound galvanometer type scanning galvanometer 10, PLC 13, laser controller 14, etc.) connected wirelessly or wiredly.

[0101] The display unit 205 includes a display unit, a video codec, a GPU (graphics processing unit), a memory for screen data, etc., generates a UI screen, etc., and displays it on the display unit. The user can also input various parameters of instructions to the laser controller 14 via the input unit 203 in the state where the UI screen is displayed on the display unit 205.

[0102] (5) Description of the workpiece W

[0103] Next, use Figure 10 and Figure 11 to describe the workpiece W to be welded. Figure 10It is a perspective view showing a schematic structure of a stator 50 that serves as a stator of an electric motor for an electric vehicle or the like. As shown in this figure, the stator 50 has a stator core 51 with a substantially cylindrical shape and a plurality of rectangular wires (coil segments) 52 inserted into a plurality of slots provided in the stator core 51. The rectangular wire 52 is a conductor (wire) having a rectangular cross-section. Usually, the rectangular wire 52 is a rectangular wire made of pure copper, but it can also be made of a metal material with high conductivity such as an alloy mainly composed of copper or an alloy composed of copper and aluminum.

[0104] The end portions of each rectangular wire 52 protrude from the upper end portion of the stator core 51, and the laser device 1 laser-welds the front end portions of two adjacent rectangular wires 52 in the radial direction of the stator core 51 to each other.

[0105] In order to prevent jamming when inserting into the slot 53, each rectangular wire 52 is pre-cut so that the front end is tapered. An example of the shape of the rectangular wire 52 is shown in Figure 11 . As shown in Figure 11 (b), the rectangular wire 52 includes a base portion 52d and a neck portion 52e having a width in the y-axis direction smaller than that of the base portion 52d. As shown in Figure 11 (a), the neck portion 52 has a gabled roof shape with two inclined surfaces 52a and 52b. In the welding process of the front end of the rectangular wire 52, the insulating coating portion on the front end side is peeled off, the front end portions of the corresponding two rectangular wires are butt-jointed, and the butt-jointed front end portions are opposed to the laser device 1 and laser is irradiated. As described above, in the present embodiment, since the front end side of the rectangular wire 52 has a gabled roof shape, if welding is performed on this shape without consideration, a large amount of spatter may be generated. Therefore, the laser device 1 focuses the laser on the inclined surface 52b of the corresponding two rectangular wires 52 close to the butt-joint surface 52c for laser irradiation.

[0106] In addition, due to deviations in the processing accuracy of each rectangular wire 52, the mechanism accuracy of the fixing jig 15, the insertion condition into the slot 53, etc., a gap (clearance, void) or height difference may sometimes occur when the front end portions of the two rectangular wires 52 are butt-jointed.

[0107] (6) The operation of the welding process by the laser device 1

[0108] Next, the operation of the laser device 1 will be described with reference to Figure 12 and Figure 13 .

[0109] First, place the workpiece W on the workpiece setting table 11 (step S101). The control PC12 sets laser parameters (laser output, acceleration time, deceleration time, etc.) for each of the first oscillator 2 and the second oscillator 3 via the laser controller 14 (step S102). The user operates the input unit 203 of the control PC12 to input the machining pattern data used by the compound galvanometer type scanning galvanometer 10 during the laser irradiation in the first step and the second step, and the control PC12 registers the machining pattern data in the storage unit 202 (step S103). In the present embodiment, the machining pattern data representing a "straight line" trajectory is registered. The processing of step S101, step S102, and step S103 does not necessarily need to be performed in this order.

[0110] Next, move the workpiece setting table 11 on which the workpiece W is placed, and position the workpiece W directly below the image processing unit 9. Next, perform the position measurement of each rectangular line 52 by the image processing unit 9 (step S104). Specifically, the illumination device 101 projects a plurality of stripe patterns from a plurality of different directions onto the workpiece W by the stripe projection method, captures each image by the imaging device 102, and the controller 103 synthesizes the captured images to calculate the 3D shape. Based on this 3D shape, the controller 103 of the image processing unit 9 measures the center position and height of each rectangular line 52, and generates CSV data (coordinate table 112) recording the measurement results. The image processing unit 9 sends the CSV data (coordinate table 112) recording the measurement results to the control PC12. At this time, the CSV data can be sent from the image processing unit 9 to the control PC12 either via a wireless or wired network, or via a portable recording medium such as a USB memory or an SD memory card.

[0111] Next, the laser device 1 performs laser processing. In the present embodiment, it is assumed that the scanning movable range of the compound galvanometer type scanning galvanometer 10 covers the entire size of the workpiece W. However, in the case of performing welding processing of a motor that is larger than the scanning working range of the galvanometer type scanning galvanometer, the laser device 1 can perform welding processing while rotating the workpiece W using the θ-axis table 11θ of the workpiece setting table 11. Depending on the size of the motor, welding processing can be performed either every quarter rotation or every eighth rotation.

[0112] The laser device 1 repeats the processing from step S105 to step S115 for each pair of rectangular lines 52 to be welded.

[0113] The control unit 201 that controls the PC12 refers to the coordinate table 112 and acquires the position information of a pair that is currently being processed (step S106). The position information acquired here includes the center coordinates and height information of at least two rectangular lines respectively.

[0114] The control unit 201 determines the laser irradiation positions of the following first step and second step to be the inner positions of the respective rectangular lines 52 (step S107). The so-called inner position, referring to Figure 11 (a), means on the inclined surface 52b close to the butting surface 52c of each rectangular line 52.

[0115] In addition, the control unit 201 determines the midpoint of the heights of the two rectangular lines 52 as the focal position (step S108). If there is no height difference between the two rectangular lines 52, the first laser L1 and the second laser L2 are focused on the Figure 14 position of JF (orthogonal focus) shown in (a). If there is a height difference between the two rectangular lines 52, the first laser L1 and the second laser L2 are focused on the Figure 14 position of JF shown in (b). Even if the height difference is about 2 mm, the laser device 1 of the present embodiment can perform processing with a sufficiently high welding quality.

[0116] Next, the laser device 1 performs the laser irradiation of the first step (step S109). Figure 15 (a) shows the irradiation trajectories l1 of the first laser L1 and the second laser L2 in the first step. In the first step, the first laser L1 and the second laser L2 are irradiated approximately linearly 1.5 times reciprocally in the y-axis direction at a speed of 500 mm / s on the inclined surface 52b of one rectangular line 52. Here, as Figure 15 (a) shows, the focused spot diameter of the first laser L1 is larger than the focused spot diameter of the second laser L2. As an example, in the present embodiment, the focused spot diameter of the first laser L1 is 1050 μm, and the focused spot diameter of the second laser L2 is 40 μm. In addition, the size of the rectangular line 52 used in the present embodiment is approximately 2.0 mm × 3.0 mm.

[0117] When the irradiation of the first step ends, the laser device 1 stops the laser output and jumps to another rectangular line 52 (moves the laser irradiation position) (step S110). In the case of rectangular line butt welding, due to the thickness of the insulating coating, some gaps are generated between the rectangular lines. The size of the gaps is generally about 0.4 mm to 1.0 mm. If the laser passes through this gap, it will cause damage to the lower part of the rectangular line. Therefore, when moving the laser irradiation position from one rectangular line to another, the laser output is stopped. Thus, it is possible to prevent the laser from passing through the gap.

[0118] Next, the laser device 1 performs laser irradiation in the second step (step S111). Figure 15 (b) shows the irradiation trajectories l2 of the first laser L1 and the second laser L2 in the second step. In the second step, the first laser L1 and the second laser L2 are irradiated approximately linearly 1.5 times reciprocally in the y-axis direction at a speed of 500 mm / s on the inclined surface 52b of the other rectangular wire 52.

[0119] Even when the irradiation in the second step ends and no molten balls of the desired size are formed at the front ends of the two rectangular wires (No in step S112), the laser output is stopped, and the process jumps to the other rectangular wire 52 (step S113). Then, the irradiation in the first step is repeated. When the irradiation in the second step ends and molten balls of the desired size are formed at the front ends of the two rectangular wires (Yes in step S112), the laser irradiation position is moved to the next pair of rectangular wires (step S114), and the process returns to the process of step S106.

[0120] The laser device 1 sprays nitrogen as a protective gas onto the welding surface of the rectangular wire 52 at a rate of 5 L / min to 100 L / min simultaneously with the irradiation of the first laser L1 and the second laser L2, or from before the irradiation to the end of the irradiation or for a longer time. More preferably, it is sprayed at a rate of 10 L / min to 40 L / min. The laser device 1 prevents oxidation of the welding surface by welding the rectangular wire 52 in a nitrogen atmosphere. Thus, it is possible to suppress a decrease in welding strength and the generation of pores due to oxidation of the welding surface.

[0121] In the present embodiment, nitrogen is sprayed from the left and right using two protective gas nozzles 19a and 19b. As an example, the angle of each of the protective gas nozzles 19a and 19b with respect to the workpiece W is 30 degrees. The diameter of the front opening of the protective gas nozzles 19a and 19b (nozzle tip diameter) is preferably about 1 to 10 mm. In addition, the working distance, which is the distance from the front opening of the protective gas nozzles 19a and 19b to the workpiece W, is preferably about 5 to 15 mm. As described above, by appropriately selecting conditions such as the flow rate of the protective gas, the nozzle tip diameter, and the working distance, it is possible to suppress the wobbling of the molten balls and form beautiful molten balls.

[0122] As described above, the laser device 1 repeatedly performs the irradiation in the first step and the irradiation in the second step. Thus, the corners of the rectangular wire end faces are gradually melted and rounded, and a first fusion zone and a second fusion zone are formed on the front side of each rectangular wire 52. These fusion zones enter the gap and combine to form a single fusion zone that spans the two rectangular wires 52. Thereafter, the irradiation in the first step and the irradiation in the second step are repeated until molten balls of the desired size are formed.

[0123] In addition, it is difficult to measure the size of the molten ball during welding. Moreover, the time required to form a molten ball of a desired size at the tip of the rectangular wire 52 varies depending on the size of the rectangular wire 52 and the laser conditions, etc. Therefore, it is preferable to perform test processing in advance. Perform test processing using the rectangular wire 52 as the object, and measure the laser irradiation time until a molten ball of a desired size is formed. Then, if the laser irradiation time obtained as a result of the test processing is input to the control PC 12, and the laser parameters are set for each of the first oscillator 2 and the second oscillator 3 via the laser controller 14, in step S112, by determining whether the laser irradiation time has reached the set time, it is possible to determine whether a molten ball of a desired size has been formed.

[0124] Figure 16 It is a schematic diagram showing the shape change of the tip of the rectangular wire 52 from the start of welding until a molten ball 56 of a desired size is formed and the welding is completed. Figure 16 (a) shows the shape change in the case where there is no height difference between a pair of rectangular wires 52, Figure 16 (b) shows the shape change in the case where there is a height difference between a pair of rectangular wires 52. In either case, the first fusion zone 56a and the second fusion zone 56b formed in each rectangular wire 52 are combined to form a single molten ball straddling the two rectangular wires 52. In the case where there is a height difference, compared with the case where there is no height difference, by irradiating the laser slightly longer until the height difference is absorbed, the same melting height as in the case where there is no height difference can be achieved.

[0125] <Embodiment Effects>

[0126] The laser device 1 suppresses the occurrence of spatter by irradiating the laser at a predetermined position near the docking surface of the rectangular wire 52 with a tapered tip, and can achieve high-quality laser welding. As a result, the "trimming process" performed in the past can be omitted. In addition, the time until the molten balls formed in each rectangular wire 52 are combined can be shortened, and the production cycle time related to the manufacture of the entire stator can be shortened.

[0127] In addition, the laser device 1 forms a molten pool on the workpiece W by irradiating the first laser L1 with a wavelength of 300 nm to 600 nm and a high light absorption rate for copper by high-speed scanning. Moreover, by irradiating the second laser L2 with a small focal spot diameter and a high energy density inside the formed molten pool, a locally deeper melt depth is achieved inside the molten pool, promoting the formation of the molten pool.

[0128] In addition, compared with the existing welding device, the laser device 1 can effectively heat the workpiece W to melt it by using the first laser L1 with a relatively large focal spot diameter during welding.

[0129] In addition, the laser device 1 irradiates the first laser L1 and the second laser L2 by high-speed scanning instead of spot irradiation, generating a flow in the molten pool. This discharges the bubbles generated from the molten pool that has reached a high temperature to the outside. Therefore, porosity can be suppressed. In addition, local concentration of heat in the molten pool can be prevented, the molten pool can be stabilized, and spatter can be reduced. Porosity or spatter is the main cause of welding defects such as poor jointing. Therefore, according to the laser device 1 and the welding method using these devices, the generation of welding defects can be suppressed.

[0130] In addition, the laser device 1 stops the laser output between the irradiation in the first step and the irradiation in the second step. Therefore, it is possible to suppress the laser from passing through the gap generated when the rectangular wire 52 is butted, and it is possible to suppress carbonization or insulation failure of the coating part accompanied by the laser passing through.

[0131] <Other modification examples>

[0132] As described above, as one embodiment of the present invention, the laser device 1 has been described. However, the present invention is of course not limited to the laser device 1 described above and the welding method using the laser device 1, and the above embodiment can also be modified as follows.

[0133] Here, modification examples of the above embodiment will be described. The above embodiment can be arbitrarily combined with the modification examples described below.

[0134] (1) In the above embodiment, Figure 11 A specific example of the shape of the rectangular wire 52 has been described. However, this is only an example, and the rectangular wire 52 to be welded by the laser device 1 is not limited to Figure 11 the shape. In Figure 11 (a), the angles of the inclined surfaces 52a and 52b are symmetric about the left and right, but the angles of the inclined surfaces can also be asymmetric. In addition, the shape of the neck is not limited to the shape of the neck 52e in Figure 11 (b). For example, it can also be the shape of the neck 52f shown in Figure 17 (a) or the shape of the neck 52g shown in Figure 17 (b). As long as at least the front end side of the rectangular wire 52 is convex and can prevent jamming when inserted into the slot.

[0135] (2) In the above embodiment, two lasers with different wavelengths (the first laser L1 and the second laser L2) are overlapped to perform welding processing of the rectangular wire 52. However, this is only an example. By using a high-power blue laser or green laser, the rectangular wire 52 can be welded with a single laser. Figure 18 The device structure at this time is shown. Figure 18 The laser device 1a of Figure 4The laser device 1 is different in that it does not have the second oscillator 3 for IR laser, and uses a common galvanometer type scanning mirror 10a instead of the composite galvanometer type scanning mirror 10. For the galvanometer type scanning mirror 10a, as an example, a 3D galvanometer type scanning mirror having a focus shift function in the z direction is described, but it is not limited to this structure, and it may also be a 2D galvanometer type scanning mirror that only performs scanning in the xy direction without a focus shift function and a structure combined with an fθ lens.

[0136] (3) In the above embodiment, the case where the trajectories (irradiation trajectories) l1 and l2 perform 1.5 reciprocations of linear reciprocating irradiation respectively is described, but of course it is not limited to 1.5 reciprocations, and it may also be 2 reciprocations or 2.5 reciprocations. It is preferable to determine an appropriate irradiation time in consideration of the balance between the melting amount of the rectangular wire 52 and the time loss of the jump step.

[0137] In addition, the irradiation trajectories of the laser irradiation in the first step and the second step are not limited to linear reciprocating irradiation. In the first step and the second step, circular rotational irradiation may be performed on the inclined surface 52b of each rectangular wire 52, or as Figure 19 the trajectories (irradiation trajectories) l3 and l4 shown, elliptical rotational irradiation may be performed. It is preferable to use machining graphic data suitable for the size and shape of the rectangular wire 52. In addition, rotational irradiation across two rectangular wires 52 is not suitable for the welding process of this embodiment. Since there is a gap between the two rectangular wires 52, it is necessary to stop the laser output when crossing the gap. As a result, the on / off control of the laser output occurs frequently, and this on / off control has an adverse effect on the production cycle time.

[0138] (4) In the above embodiment, the height of each lead is measured by the image processing unit 9, and the midpoint thereof is used as the focus position, but this is not a necessary structure. The image processing unit 9 may also use a predetermined reference position as the focus position without measuring the height of each lead. Predict the approximate height deviation, and set the position that can absorb this deviation as the reference position. In addition, in all pairs of welding processes, the same reference position is used as the focus position, so that there is no need to control the change of the focus position for each pair.

[0139] As described above, if the same reference position is set as the focus position in all pairs of welding processes, the function of height measurement based on image processing can be omitted, thereby reducing the cost related to the image processing system. In addition, the number of management parameters of the processing conditions in motor production can be reduced.

[0140] (5) Further, in the case where the height of each lead is measured by the image processing unit 9 as in the above-described embodiment, it is preferable that the total irradiation time of the higher rectangular wire is longer than the total irradiation time of the lower rectangular wire, so that more of the higher rectangular wire melts. Thereby, a beautiful molten ball with equal left and right sides can be formed in a short time.

[0141] (6) During welding, if there is a sharp temperature rise on the workpiece W, spatter may sometimes occur. Therefore, instead of irradiating the first laser L1 and the second laser L2 simultaneously, only the first laser L1 with a high absorption rate for the workpiece W can be irradiated first, and the second laser L2 can be additionally irradiated after a predetermined time. Therefore, a sharp temperature rise on the welding surface can be suppressed, and the occurrence of spatter can be suppressed. Furthermore, for the welding surface whose temperature has become high due to the first laser L1, the absorption rate of the wavelength of the second laser L2 increases, so that the energy of the second laser L2 can be effectively absorbed by the workpiece W, resulting in a shortening of the processing time. In this case, it is preferable to irradiate the second laser L2 with a delay of 1 millisecond or more after irradiating the first laser L1.

[0142] (7) The focused spot diameter of the first laser L1 is not limited to 1050 μm. The focused spot diameter of the first laser L1 can be appropriately selected according to the cross-sectional area of the rectangular wire 52. For example, the focused spot diameter of the first laser L1 can be 1% to 30% of the cross-sectional area.

[0143] Further, the focused spot diameter of the second laser L2 is not limited to 40 μm. The focused spot diameter of the second laser L2 can be about 10 μm to 100 μm, and preferably it is less than one-tenth of the focused spot diameter of the first laser L1.

[0144] The focused spot diameter of each laser depends on the core diameter of the transmission optical fiber, the focal length of the collimating lens, and the focal length of the condensing lens, and can be calculated by focused spot diameter = core diameter of the transmission optical fiber × (focal length of the condensing lens / focal length of the collimating lens). Therefore, by adjusting these optical systems, the focused spot diameter of each laser can be changed.

[0145] (8) In the above-described embodiment, the scanning speeds of the first laser L1 and the second laser L2 were described as 500 mm / s, but the scanning speeds of the first laser L1 and the second laser L2 are not limited thereto, as long as they are in the range of 100 to 1000 mm / s.

[0146] (9) In the above-described embodiment, the irradiation of the first step and the irradiation of the second step are repeatedly performed until a molten ball of a desired size is formed. However, this is just an example. In the case where it is not necessary to particularly form a molten ball, it may be configured to repeatedly perform the irradiation of the first step and the irradiation of the second step until a part of the fusion zone formed on one rectangular wire 52 and a part of the fusion zone formed on another rectangular wire 52 enter the gap. Alternatively, it may be configured to repeatedly perform the irradiation of the first step and the irradiation of the second step until the first fusion zone and the second fusion zone are joined.

[0147] (10) In the above-described embodiment, the case where the first laser L1 is multimode and the second laser L2 is single mode is described, but this is just an example, and the mode of the light of each laser is not limited.

[0148] (11) In the above-described embodiment, in order to avoid interference with the operation of the image processing unit 9 or the compound galvanometer type scanning galvanometer 10 and to effectively supply nitrogen, side nozzle type protective gas nozzles 19a and 19b are used, but the protective gas nozzle is of course not limited to the side nozzle type. The protective gas nozzle sprays nitrogen at an inclination angle of 0 to 90° with respect to the welding surface, and welding can be performed in a nitrogen atmosphere.

[0149] (12) In the above-described embodiment, the first laser L1 and the second laser L2 are circular beams, but the beam shapes of the first laser L1 and the second laser L2 are not limited thereto. For example, an elliptical beam or a rectangular beam may also be used. In this case, preferably, in the rectangular cross-section of the rectangular wire, the longitudinal direction is the major axis.

[0150] (13) In the above-described embodiment, the speed at which the laser irradiation position is moved in steps S110 and S113 may also be performed at a speed faster than the laser irradiation speed of the first step and the second step. For example, it may be performed at a speed of 1000 mm / s, which is twice the laser irradiation speed of the first step and the second step. Thereby, the production cycle time can be shortened.

[0151] (14) In the above-described laser device 1, information such as the focused spot diameter, output power, and irradiation trajectories (processing pattern data), irradiation time, irradiation speed, and irradiation times of the first laser L1 and the second laser L2 may also be input via the input unit 203 of the control PC12 in appropriate values corresponding to the dimensions of the rectangular wire in advance. In addition, when the workpiece dimensions, the finished shape of the molten ball, etc. are input, the control unit 201 may also determine the focused spot diameter, output power, irradiation trajectory, irradiation time, irradiation speed, irradiation times, etc. of the laser according to a predetermined algorithm.

[0152] Symbol Explanation

[0153] 1 Laser device

[0154] 1a Laser device

[0155] 2 First oscillator (blue semiconductor laser)

[0156] 3 Second oscillator (IR fiber laser)

[0157] 4 Beam combiner section

[0158] 6 Focus shift section

[0159] 8 Galvanometer scanning mirror section

[0160] 9 Image processing section

[0161] 10 Composite galvanometer scanning mirror

[0162] 10a Galvanometer scanning mirror

[0163] 11 Workpiece setting table

[0164] 11a Base

[0165] 11x x-axis table

[0166] 11y y-axis table

[0167] 11z z-axis table

[0168] 11θ θ-axis table

[0169] 12 Control PC (galvanometer PC)

[0170] 13 PLC

[0171] 14 Laser controller

[0172] 15 Fixed fixture

[0173] 19a, 19b Protection gas nozzle

[0174] 31, 32, 41, 42, 43 Lens

[0175] 33, 34 Mirror

[0176] 50 Stator

[0177] 51 Stator core

[0178] 52 Rectangular wire (first component, second component)

[0179] 52a Inclined surface

[0180] 52b Inclined surface

[0181] 52c Butt surface

[0182] 52d base

[0183] 52e, 52f, 52g neck

[0184] 53 groove

[0185] 56 molten ball

[0186] 56a first fusion zone

[0187] 56b second fusion zone

[0188] 81, 83 mirror

[0189] 82, 84 drive mechanism

[0190] 100 control board

[0191] 101 lighting device

[0192] 102 imaging device

[0193] 103 controller

[0194] 104 memory

[0195] 105 processor

[0196] 111 measurement program

[0197] 112 coordinate table

[0198] 201 control unit

[0199] 211 CPU

[0200] 212 RAM

[0201] 202 storage unit

[0202] 203 input unit

[0203] 204 communication unit

[0204] 205 display unit

[0205] D distance

[0206] F focal length

[0207] JF orthoscopic focus

[0208] l1, l2, l3, l4 trajectory

[0209] L1 first laser

[0210] L2 second laser

[0211] Steps S1 to S4, S11 to S13, S101 to S115

[0212] Workpiece W

[0213] X, Y, and Z axes

[0214] Angle θ

Claims

1. A welding method, which is a welding method for butting a first component and a second component whose front end side is convex, making the front end face a laser device, and performing welding using a laser, characterized in that: include: In the first step, the front end of the first component near the butt joint surface is irradiated with the laser to form a first fusion zone; as well as In the second step, the laser is irradiated to a position of the front end of the second component close to the butt surface to form a second fusion zone.

2. The welding method according to claim 1, characterized in that: The first member and the second member are rectangular wires constituting stator coils. The convex shape on the front end side is a gable roof shape having a first inclined surface formed at the front end portion of the rectangular line and a second inclined surface formed not parallel to the first inclined surface, The first step and the second step irradiate the laser beam onto one of the first inclined surface and the second inclined surface that is located close to the butting surface.

3. The welding method according to claim 2, characterized in that: In the first step, the first component is irradiated reciprocally on the inclined surface close to the butt surface in a substantially linear manner to form the first fusion zone. In the second step, the second fusion zone is formed by reciprocatingly irradiating the inclined surface of the second member located near the butting surface in a substantially linear shape.

4. The welding method according to claim 3, characterized in that: The welding method alternately repeats the laser irradiation of the first step and the laser irradiation of the second step.

5. The welding method according to claim 4, characterized in that: The welding method alternately repeats the laser irradiation of the first step and the laser irradiation of the second step until the first fusion zone is joined to the second fusion zone.

6. The welding method according to claim 4, characterized in that: The welding method alternately repeats the laser irradiation of the first step and the laser irradiation of the second step until the first fusion zone and the second fusion zone are combined to form a molten ball of a predetermined size.

7. The welding method according to claim 4, characterized in that: There is a gap between the first component and the second component, The welding method alternately repeats the laser irradiation of the first step and the second step until the first fusion zone and the second fusion zone enter the gap.

8. The welding method according to any one of claims 4 to 7, characterized in that: The welding method further includes a jump step, in which, after laser irradiation of one rectangular line is performed, the laser irradiation position is moved to another rectangular line while the laser irradiation is stopped, during the alternating repetition of the laser irradiation of the first step and the laser irradiation of the second step.

9. The welding method according to claim 8, characterized in that: The first step is to irradiate the inclined surface of the first component with the laser beam 1.5 times in a substantially linear manner. In the second step, the laser beam is irradiated onto the inclined surface of the second member in a substantially linear manner and reciprocated 1.5 times.

10. The welding method according to claim 1, characterized in that: The welding method comprises: an imaging step of imaging the first component and the second component to be welded; and The control step analyzes the image captured by the imaging step to obtain position information of the first component and the second component, and determines an irradiation position of the laser beam based on the acquired position information.

11. The welding method according to claim 1, characterized in that: The welding method comprises: an imaging step of imaging the first component and the second component to be welded; and The control step analyzes the image captured by the imaging step to obtain height information of the first component and the second component, and determines a midpoint between the heights of the first component and the second component as a focus position based on the obtained height information.

12. The welding method according to claim 1, characterized in that: The laser light includes a first laser light and a second laser light having wavelengths different from each other.

13. The welding method according to claim 12, characterized in that: The wavelength of the first laser is 300-600 nm.

14. The welding method according to claim 12, characterized in that: The wavelength of the second laser is 780nm-1100nm.

15. The welding method according to claim 12, characterized in that: The output power of the first laser and the second laser is 500W to 3kW.

16. The welding method according to claim 12, characterized in that: A focused spot diameter of the second laser is smaller than a focused spot diameter of the first laser.

17. The welding method according to claim 16, characterized in that: The focus spot diameter of the second laser is less than one tenth of the focus spot diameter of the first laser.

18. The welding method according to claim 16, characterized in that: The focus spot diameter of the second laser is 10 μm to 100 μm.

19. The welding method according to claim 1, characterized in that: Simultaneously with the laser irradiation or from before the irradiation to the end of the irradiation or for a longer period of time, nitrogen gas is sprayed toward the front end portion at a flow rate of 5 L / min to 100 L / min and an inclination angle of 0 to 90 degrees relative to the front end portion.

20. A laser device for welding the front ends of a first component and a second component having a convex front end side, wherein: have: an oscillator which oscillates laser light; A galvanometer scanning mirror unit that displaces the laser light in an arbitrary direction for irradiation; a control unit that controls the oscillator and the galvanometer scanning mirror unit, The control unit controls the oscillator and the galvanometer scanning mirror unit to irradiate the laser to the front end of the first component near the butt joint surface to form a first fusion zone, and irradiate the laser to the front end of the second component near the butt joint surface to form a second fusion zone.

21. The laser device according to claim 20, characterized in that The laser device further includes an image processing unit that captures images of the first component and the second component to detect position information. The control unit determines an irradiation position of the laser beam using the position information detected by the image processing unit.

Images