LASER WELDING PROCESS AND PROCESS FOR MANUFACTURING A ROTATING ELECTRIC MACHINE

Abstract

A laser welding method according to one embodiment is a laser welding method for welding an end section of a first wire-shaped element and an end section of a second wire-shaped element by alternately irradiating the end section of the first wire-shaped element and the end section of the second wire-shaped element with a laser beam, wherein the second wire-shaped element is adjacent to the first wire-shaped element. The laser welding method comprises a process of irradiating the laser beam along a first motion path on the end section of the first wire-shaped element, wherein the first motion path is loop-shaped; a process of stopping the irradiation of the laser beam and moving an irradiation position of the laser beam from the end section of the first wire-shaped element to the end section of the second wire-shaped element along a second motion path, wherein the second motion path is linear;a process of irradiating the laser beam along a third motion path at the end section of the second wire-shaped element, wherein the third motion path is loop-shaped; and a process of stopping the irradiation of the laser beam and moving the irradiation position of the laser beam from the end section of the second wire-shaped element to the end section of the first wire-shaped element along a fourth motion path, wherein the fourth motion path is linear. The second motion path is tangent to the first and third motion paths; and the fourth motion path is tangent to the first and third motion paths at a position opposite the second motion path.

Description

[Technical field]

[0001] Embodiments of the invention relate to a laser welding method and a method for manufacturing a rotating electrical machine. [State of the art]

[0002] For example, a technology has been proposed in which two wire-shaped members are arranged close to each other, and a laser beam is irradiated onto an end portion of one wire-shaped member and an end portion of the other wire-shaped member adjacent to the one wire-shaped member to weld the end portions of the two wire-shaped members together. In such a case, if there is a gap between the end portions of the two wire-shaped members, there is a risk that the laser beam will leak through the gap between the end portions. If the laser beam leaks through the gap between the end portions, there is a risk, for example, of damaging a coating on the side surface of the wire-shaped member and / or damaging a member located on the opposite side to the end portions of the wire-shaped members to be welded.

[0003] Therefore, a technology has been proposed that uses a jig to tightly bond the end portions of the wire-shaped elements together. However, the end portion of the wire-shaped element is subject to variations in dimensions, shape, deformation, etc., making it difficult to prevent the occurrence of a gap between the end portions of the wire-shaped elements.

[0004] Therefore, a technology is proposed in which the laser beams are irradiated individually onto the end portions of the two wire-shaped elements. This prevents the laser beams from being irradiated into the gap between the end portions of the wire-shaped parts. However, such a technique requires a complex configuration and / or control program of a laser welding device.

[0005] A technology has also been proposed in which the irradiation of the laser beam is stopped when the irradiation position of the laser beam is moved from the end portion of one wire-shaped member to the end portion of the other wire-shaped member. This can prevent the laser beam from being irradiated into the gap between the end portions of the wire-shaped members. However, the end portion of the wire-shaped member has variations in size, shape, deformation, etc. The dimensions of the gap also fluctuate. In such a case, the dimensions of the gap can be measured in advance, and the timing at which the irradiation of the laser beam is stopped and / or the stop time can be adjusted each time. However, this technology requires a method and / or a measuring device that measures the dimensions of the gap.

[0006] It is therefore desirable to develop a technology that can suppress the irradiation of the laser beam into the gap between the end parts of the wire-shaped elements with a simple method. [Prior art documents][Patent literature] Patent Literature 1: JP 2018-20340 A (Kokai) Patent Literature 2: International Publication No. WO 2019 / 159737 A [Summary of the invention][Problem to be solved by the invention]

[0007] A problem to be solved by the invention is to provide a laser welding method and a method for manufacturing a rotating electric machine that can suppress the irradiation of a laser beam into a gap between end portions of wire-shaped members with a simple method. [Means of solving the problem]

[0008] A laser welding method according to an embodiment is a laser welding method for welding an end portion of a first wire-shaped member and an end portion of a second wire-shaped member by alternately irradiating a laser beam to the end portion of the first wire-shaped member and the end portion of the second wire-shaped member, the second wire-shaped member being adjacent to the first wire-shaped member. The laser welding method includes a process of irradiating the laser beam along a first movement path at the end portion of the first wire-shaped member, the first movement path being loop-shaped; a process of stopping the irradiation of the laser beam and moving an irradiation position of the laser beam from the end portion of the first wire-shaped member to the end portion of the second wire-shaped member along a second movement path, the second movement path being linear;a process of irradiating the laser beam along a third movement path at the end portion of the second wire-shaped member, the third movement path being loop-shaped; and a process of stopping the irradiation of the laser beam and moving the irradiation position of the laser beam from the end portion of the second wire-shaped member to the end portion of the first wire-shaped member along a fourth movement path, the fourth movement path being linear. The second movement path contacts the first and third movement paths; and the fourth movement path contacts the first and third movement paths at a position opposite to the second movement path. [Brief description of the drawings] Fig. 1 is a schematic perspective view illustrating a stator. Fig. Figure 2 is a schematic view illustrating a segment before assembly on a core. Fig. Figure 3 is a schematic view illustrating the coil mounted on the core. Fig. 4 is a schematic view illustrating laser welding of conductor parts according to a comparative example. Fig. 5 is a schematic diagram illustrating laser welding of conductor parts according to another comparative example. Fig. 6 is a schematic view illustrating laser welding of conductor parts according to the embodiment. Fig. 7A and Fig. 7B are schematic views illustrating the movement paths of the irradiation position. Fig. 8A and Fig. 8B are schematic views illustrating the movement paths of the irradiation position according to another embodiment. [Detailed description]

[0009] A laser welding method according to this embodiment can be used when welding end portions of closely arranged wire-shaped members together. A rotating electrical machine such as a motor, a generator, or the like includes a coil wound on a core. In recent years, a coil wound on a core is formed by inserting a plurality of segments into slots and then irradiating an end portion of one segment and an end portion of a segment adjacent to the segment with a laser beam. Therefore, the laser welding method according to the present invention will be described below by way of example, illustrating a method for manufacturing a stator. In other words, the present invention is applicable to a method for manufacturing a rotating electrical machine.

[0010] Although a wire-shaped member having a quadrangular cross-section (e.g., a conductor part 31a of a segment 31 described below) is illustrated to illustrate the method for manufacturing the stator, the invention is also applicable to a wire-shaped member having, for example, a polygonal cross-section, etc.

[0011] Also, in the description, the movement path of the laser beam irradiation position is also the movement path along which the center of the laser spot moves when the laser beam is irradiated; and when the irradiation of the laser beam is stopped, the movement path of the irradiation position is the movement path along which the center of the laser spot would move if the laser spot is assumed to be formed. The movement path of the laser beam irradiation position can be predetermined, for example, according to the cross-sectional shape, cross-sectional dimension, etc. of the wire-shaped member (e.g., the conductor part 31a of the segment 31 described below). For example, the data of the predetermined movement paths are stored in a controller of a laser welding device, etc., and used when performing the laser welding method described below.

[0012] The embodiments will now be illustrated with reference to the drawings. Similar components are designated by the same reference numerals throughout the drawings; a detailed description will be omitted where appropriate.

[0013] First, a stator 1 is shown.

[0014] Fig. 1 is a schematic perspective view of the stator 1.

[0015] As in Fig. 1, the stator 1 comprises a core 2 and a coil 3.

[0016] In the core 2, several ring-shaped magnetic elements can be arranged in the axial direction of the stator 1 (in Fig. 1 in the Z direction). The magnetic element can be formed, for example, from an electrical steel sheet (a silicon steel sheet). The core 2 consists of a yoke 21 and a plurality of teeth 22. The yoke 21 is tubular and is located on the outer peripheral side of the core 2. The plurality of teeth 22 are arranged on the inner peripheral surface of the yoke 21 at equal intervals. Each of the plurality of teeth 22 has a configuration that protrudes from the inner peripheral surface of the yoke 21 toward the center of the core 2 and extends in the axial direction of the stator 1. In addition, a groove located between the tooth 22 and the tooth 22 is used as a slot 23. The shapes, number, and sizes of the teeth 22 are not limited to those shown and can be appropriately changed depending on the application, size, specifications, etc. of the rotating electrical machine in which the stator 1 is incorporated.

[0017] The coil 3 contains several segments 31.

[0018] Fig. Figure 2 is a schematic view showing the segment 31 before assembly on the core 2.

[0019] As in Fig. As shown in Figure 2, the segment 31 includes the conductor portion 31a and an insulating film 31b. The outer shape of the conductor portion 31a before assembly to the core 2 may be substantially U-shaped. The conductor portion 31a is formed from a material with high conductivity. For example, the conductor portion 31a is formed from so-called pure copper or a material with copper as its main component. The conductor portion 31a may also be formed from a rectangular wire. The rectangular wire is a wire-shaped element with a quadrangular cross-section. The cross-sectional dimensions of the rectangular wire may be, for example, approximately 1 mm to 4 mm.

[0020] The insulating film 31b covers the outer surface of the conductor part 31a. However, near the two end portions of the conductor part 31a, the insulating film 31b is not present, and the conductor part 31a is exposed. The insulating film 31b is made of, for example, enamel, etc.

[0021] Fig. 3 is a schematic representation of the coil 3 mounted on the core 2.

[0022] As in Fig. As shown in Figure 3, the segment 31 is located inside the slot 23. The two ends of the segment 31 protrude from one end portion of the core 2. The part of the segment 31 that protrudes from one end portion of the core 2 extends toward the adjacent segment 31.

[0023] In addition, the vicinity of the portion of the conductor part 31a exposed under the insulating layer 31b extends in the axial direction of the core 2 (in Fig. 3 the Z direction). The portion of the conductor part 31a exposed under the insulating layer 31b overlaps the portion of the adjacent conductor parts 31a exposed under the insulating layer 31b in the circumferential direction of the core 2 (a direction around the central axis of the core 2).

[0024] The end sections of the adjacent conductor parts 31a are laser-welded together. A coil 3 is formed from several segments 31 connected via a welded section 31c.

[0025] In such a case, the plurality of coils 3 may be arranged in the radial direction of the core 2 (a direction passing through the central axis of the core 2 orthogonal to the Z direction). As shown in Fig. 1, for example, the three coils 3 of a U-phase, a V-phase, and a W-phase may be included. The external shapes, number, size, etc. of the coils 3 and the segments 31 are not limited to those shown and may be changed depending on the application, size, specifications, etc. of the rotary electric machine in which the stator 1 is incorporated. For example, four coils 3 may be arranged in the radial direction of the core 2.

[0026] A method for manufacturing the stator 1 is illustrated below.

[0027] First, the core 2 is formed. For example, a plurality of plate-shaped magnetic elements are formed, including parts used to form the yoke 21 and the plurality of teeth 22. The magnetic element is formed, for example, by punching an electrical steel sheet with a thickness of approximately 0.05 mm to 1.0 mm. Then, the plurality of magnetic elements are stacked, and the core 2 is formed, for example, by welding and / or caulking the plurality of magnetic elements. The core 2 can also be formed by press-molding a magnetic material powder and a resin binder.

[0028] Then, the plurality of segments 31 used as components of the coil 3 are formed.

[0029] First, the insulating film 31b is formed by applying a coating containing varnish, etc., to the outer surface of a rectangular wire of a prescribed length. A coating containing varnish, etc., may be applied to the surface of a rectangular wire, and the rectangular wire may be cut to a prescribed length. Furthermore, a rectangular wire with an enamel coating, etc., may be obtained, and the rectangular wire may be cut to a prescribed length.

[0030] Then, as in Fig. 2, the insulating film 31b is removed near both end portions of the conductor part 31a to expose the conductor part 31a.

[0031] Subsequently, the conductor part 31a is brought into a substantially U-shaped form by bending the conductor part 31a.

[0032] In this way, several segments 31 can be formed.

[0033] Then, as in Fig. 3, each of the plurality of segments 31 is mounted in predetermined slots 23 of the core 2. For example, each of the plurality of segments 31 is mounted in the predetermined slots 23 from the axial direction of the core 2 (in Fig. 1 the Z direction). In such a case, a segment 31 is inserted so that it spans several slots 23. The coil 3 according to this embodiment can be a coil having a so-called distributed winding. The coil 3 according to the embodiment can also be a coil having a so-called wave winding.

[0034] As in Fig. 3, the part of the segment 31 protruding from the core 2 is bent towards the adjacent segment 31. Then, in addition, the vicinity of the portion of the conductor part 31a exposed under the insulating film 31b in the axial direction of the core 2 (in Fig. 3 the Z direction). The portion of the conductor part 31a exposed under the insulating layer 31b overlaps the portion of the adjacent conductor part 31a exposed under the insulating layer 31b in the circumferential direction of the core 2.

[0035] Then, by repeatedly performing the above-described procedure, multiple sets of multiple segments 31 arranged in the circumferential direction of the core 2 are arranged in the radial direction of the core 2.

[0036] Although a case is illustrated where the bending is performed after mounting the multiple segments 31 in the slots 23, the bending is not limited to this. For example, the bending of the multiple segments 31 may be performed, and each of the multiple segments 31 on which the bending is performed may be mounted in the prescribed slots 23. In such a case, the segment 31 on which the bending is performed may be mounted from the inside of the core 2 to the outside.

[0037] Also, the openings of the slots 23 can be covered by a tubular insulating cover on the inside of the core 2 in which the plurality of segments 31 are mounted.

[0038] Then, the plurality of coils 3 mounted in the slots 23 are formed by welding the end portions of the adjacent segments 31 (conductor parts 31a) together.

[0039] During welding, a jig may be used to bring the end portions of the adjacent conductor parts 31a closer to each other. For example, a jig comprising an annular member on the inner side of the plurality of segments 31 arranged in the circumferential direction of the core 2 and an annular member on the outer side of the plurality of segments 31 may be used. When the annular member located on the inner side of the multiple segments 31 is mounted, one end portion of each of the multiple conductor parts 31a is pressed toward the outer side of the core 2. When the annular member is mounted on the outer side of the multiple segments 31, the other end portion of each of the multiple conductor parts 31a is pressed toward the inner side of the core 2. Therefore, the jig moves the end portions of the adjacent conductor parts 31a toward each other. In addition, the plurality of conductor parts 31a are held by the jig.

[0040] The configuration of the jig is not limited to that of the example. It is sufficient if the jig causes the end portions of the adjacent conductor parts 31a to approach each other. Welding can also be performed without using a jig. However, by using a jig, the quality of the weld portion 31c can be improved and / or the work efficiency of the welding process can be improved.

[0041] The welding of the end portions of the adjacent conductor parts 31a to each other can be performed by irradiating a laser beam onto the end portions of the conductor parts 31a. In other words, the end portions of the adjacent conductor parts 31a can be welded to each other by laser.

[0042] Laser welding can utilize a laser beam with a wavelength in the infrared range. Using a laser beam with a wavelength in the infrared range makes it easy to irradiate a relatively high-power laser beam. For example, the laser beam power can be approximately 4 kW.

[0043] The laser welding device used to weld the end portions of the conductor parts 31a can be, for example, a fiber laser (fiber laser), a disk laser (disk laser), etc. It is advantageous if the laser welding device is a CW (continuous wave laser) welding device that can continuously emit a laser beam. Furthermore, the irradiation position of the laser beam in the laser welding device is movable. The laser welding device can include, for example, a galvano mirror, etc.

[0044] If the laser welding of the end portions of the conductor parts 31a is performed in ambient air, there is a risk that the weld portion 31c will be oxidized and / or the quality of the weld portion 31c will be reduced due to the occurrence of voids, etc. Therefore, it is advantageous, for example, to perform the laser welding of the end portions of the conductor parts 31a in an atmosphere containing an inert gas such as nitrogen, argon, etc., or to supply an inert gas near the end portions of the conductor parts 31a where the laser welding is performed. In this way, the quality of the weld seam 31c can be improved.

[0045] The Fig. 1 and Fig. The welding portion 31c shown in FIG. 3 is formed by welding the end portions of the adjacent conductor parts 31a together. Furthermore, a coil 3 is formed by connecting the plurality of segments 31 (the conductor parts 31a) in series. A plurality of coils 3 are also formed, arranged in the radial direction of the core 2. For example, the three coils 3 of the U-phase, V-phase, and W-phase can be formed by sliding one slot 23 each.

[0046] Details of welding the end portions of the segments 31 (the conductor parts 31a) are described below.

[0047] Then, the exposed portions of the conductor parts 31a of the coil 3 are insulated by coating with a resin, etc.

[0048] Then, the plurality of coils 3 are fixed on the core 2. For example, varnish is dripped into the gaps between the coil 3 and the slots 23, and the coil 3 is fixed to the core 2 by curing the varnish.

[0049] This is how stator 1 can be manufactured.

[0050] The welding of the end portions of the segments 31 (the conductor parts 31a) will now be described in more detail. As described above, the end portions of the adjacent conductor parts 31a are welded together by irradiating a laser beam onto the end portions of the conductor parts 31a. In such a case, if a gap exists between the end portions of the adjacent conductor parts 31a, the laser beam can be irradiated across the gap onto the segment 31 on the side opposite the end portions to be welded. As shown in Fig. 2 and Fig. As shown in Figure 3, the insulating film 31b is located on the outer surface of the conductor portion 31a. Therefore, when the laser beam is irradiated through the gap onto the segment 31 on the side opposite the end portions to be welded, the insulating film 31b may be damaged by the laser beam. Furthermore, there are cases where, for example, components and the like located on the segment 31 on the side opposite the end portions to be welded may be damaged by the laser beam.

[0051] In such a case, the distance between the end portions of the adjacent conductor parts 31a can be reduced by using the jig described above. However, the end portion of the conductor part 31a is subject to dimensional fluctuations, shape variations, deformation, etc. Therefore, even with the use of the jig, it is difficult to eliminate the gap between the end portions of the adjacent conductor parts 31a.

[0052] Fig. 4 is a schematic diagram of laser welding of the conductor parts 31a according to a comparative example.

[0053] Fig. 4 shows when laser beams are irradiated individually onto the end portions of the adjacent conductor parts 31a. For example, as in Fig. As shown in Figure 4, the laser beam is irradiated onto the end portion of one conductor part 31a; and another laser beam is irradiated onto the end portion of the other conductor part 31a. The laser beams are irradiated simultaneously.

[0054] A movement path 101 of the laser beam irradiation position at the end portion of one conductor part 31a is loop-shaped. Irradiation with the loop-shaped laser beam is continuously performed multiple times. Furthermore, the movement path 101 of the laser beam irradiation position is gradually increased. By irradiating the laser beam, the end portion of one conductor part 31a is heated to form a weld pool.

[0055] A movement path 102 of the laser beam irradiation position at the end portion of the other conductor part 31a is loop-shaped. Irradiation with the loop-shaped laser beam is continuously performed multiple times. Furthermore, the movement path 102 of the laser beam irradiation position is gradually increased. The laser beam irradiation heats the end portion of the other conductor part 31a to form the weld pool.

[0056] By gradually increasing the loop-shaped movement paths 101 and 102 of the laser beam irradiation positions, the weld pools formed between the end portions of the conductor parts 31a fuse together. Therefore, the end portion of one conductor part 31a and the end portion of the other conductor part 31a are connected via the welding portion.

[0057] By individually irradiating the end portions of the adjacent conductor parts 31a with laser beams, the laser beams are not irradiated into a gap 31a1 between the end portions of the conductor parts 31a. Therefore, the insulating layer 31b of the segment 31, etc., can be prevented from being damaged by the laser beams.

[0058] However, such a technique requires two laser welding machines, two optical systems for irradiating the laser beams and / or the control programs of the laser welding machines are complex.

[0059] Fig. 5 is a schematic view illustrating laser welding of the conductor parts 31a according to another comparative example.

[0060] As in Fig. 5, a movement path 103 of the laser beam irradiation position for the two end portions of the adjacent conductor parts 31a is looped. In such a case, the irradiation of the laser beam is stopped when the irradiation position of the laser beam moves from the outer edge of the end portion of one conductor part 31a to the outer edge of the end portion of the other conductor part 31a. Furthermore, the irradiation of the laser beam is resumed when the irradiation position of the laser beam has moved to the outer edge of the end portion of the other conductor part 31a. The looped movement path 103 of the laser beam irradiation position set for the end portions of the two conductor parts 31a is gradually reduced. By irradiating the laser beam, the weld pools formed at the end portions of the adjacent conductor parts 31a are melted between the end portions of the conductor parts 31a.Therefore, the end portion of one conductor part 31a and the end portion of the other conductor part 31a are connected via the welding portion.

[0061] By interrupting the irradiation of the laser beam when the irradiation position of the laser beam moves from the outer edge of the end portion of one conductor part 31a to the outer edge of the end portion of the other conductor part 31a, the laser beam is not irradiated into the gap 31a1 between the end portions of the conductor parts 31a. Therefore, the insulating layer 31b of the segment 31, etc., can be prevented from being damaged by the laser beam.

[0062] However, the end portion of the conductor part 31a has dimensional variations, shape variations, deformations, etc., and the dimensions of the gap 31a1 also vary. Therefore, if the irradiation of the laser beam is interrupted and resumed at a predetermined time, there is a risk that the laser beam will be irradiated into the gap 31a1 when the laser beam is irradiated and the irradiation is interrupted at the outer edges of the end portions of the conductor parts 31a. In such a case, the laser beam can be prevented from being irradiated into the gap 31a1 by extending the time for which the irradiation of the laser beam is interrupted. However, with such a technique, it is difficult to heat the end portions of the conductor parts 31a because the irradiation time of the laser beam is shortened.Furthermore, the dimensions of the gap 31a1 can be measured in advance, and the timing of stopping the laser beam irradiation and / or the stopping time (the timing of resuming the laser beam irradiation) can be set each time. However, such a technique requires a method for measuring the dimensions of the gap 31a1 and a measuring device.

[0063] Fig. 6 is a schematic view illustrating laser welding of the conductor parts 31a according to the embodiment.

[0064] In laser welding the conductor parts 31a according to the embodiment, a laser beam is alternately irradiated onto the end portion of one conductor part 31a (corresponding to an example of a first wire-shaped member) and the end portion of another conductor part 31a (corresponding to an example of a second wire-shaped member) adjacent to the one conductor part 31a to weld the end portions of the adjacent conductor parts 31a to each other.

[0065] As in Fig. 6, the laser beam is irradiated, for example, along a loop-shaped moving path 100 (which corresponds to an example of a first moving path) of the irradiation position of the laser beam at the end portion of the one conductor part 31a.

[0066] Then, the irradiation of the laser beam is stopped, and the irradiation position of the laser beam is moved from the end portion of one guide part 31a to the end portion of the other guide part 31a along a linear movement path 100b (corresponding to an example of a second movement path) of the irradiation position of the laser beam.

[0067] Then, at the end portion of the other guide part 31a, the irradiation of the laser beam is resumed, and the laser beam is irradiated along the loop-shaped moving path 100 (which corresponds to an example of a third moving path) of the irradiation position of the laser beam.

[0068] Then, the irradiation of the laser beam is stopped, and the irradiation position of the laser beam is moved from the end portion of the other guide part 31a to the end portion of the one guide part 31a along the linear movement path 100b (which corresponds to an example of a fourth movement path) of the irradiation position of the laser beam.

[0069] Thereafter, by repeating the above-described process several times, weld pools are formed by alternately irradiating the laser beam onto the end portions of the adjacent conductor parts 31a.

[0070] In such a case, for example, the loop-shaped movement path 100 of the irradiation position may have the same shape and the same size for each of the end portions of the adjacent conductor parts 31a.

[0071] Although the loop-shaped movement path 100 of the irradiation position has the same shape and size because the cross-sectional shapes and cross-sectional dimensions of the adjacent wire-shaped elements (conductor parts 31a) are the same, the shape and / or size of the loop-shaped movement path 100 of the irradiation position may be different if, for example, the cross-sectional shape and / or cross-sectional dimension of the adjacent wire-shaped elements is different.

[0072] Next, a case will be described in which the loop-shaped moving path 100 of the irradiation position has the same shape and the same size for each of the end portions of the adjacent wire-shaped elements (conductor parts 31a).

[0073] The shape of the loop-shaped movement path 100 of the irradiation position is not particularly limited. However, it is advantageous if the shape of the loop-shaped movement path 100 of the irradiation position is a shape containing curves such as a circle, an ellipse, or the like, or a shape containing curves and straight lines such as the shape shown in Fig. 6. By setting the shape of the loop-shaped movement path 100 of the irradiation position to such a shape, the operation of the galvano mirror or the like is performed smoothly.

[0074] The size of the loop-shaped movement path 100 of the irradiation position is also not particularly limited. As in Fig. However, as shown in Figure 6, it is advantageous that at the end section of one conductor part 31a, the shortest distance L between the outer edge of a laser spot 100a and the outer edge of the end section of one conductor part 31a is constant. At the end section of the other conductor part 31a, it is also advantageous that the shortest distance L between the outer edge of the laser spot 100a and the outer edge of the end section of the other conductor part 31a is constant.

[0075] In the loop-shaped movement path 100 of the irradiation position, the laser beam is irradiated, and the end portions of the adjacent conductor parts 31a are respectively heated. The weld pools formed at the end portions of the adjacent conductor parts 31a fuse between the end portions of the conductor parts 31a. Therefore, the end portion of one conductor part 31a and the end portion of the other conductor part 31a are connected to each other via the welding portion 31c.

[0076] Also, the irradiation of the laser beam is stopped when it moves from the loop-shaped movement path 100 of the irradiation position at the end portion of one conductor part 31a to the loop-shaped movement path 100 of the irradiation position at the end portion of the other conductor part 31a. As shown in Fig. For example, as shown in FIG. 6, a pair of linear irradiation position movement paths 100b may be provided, connecting the looped irradiation position movement path 100 at the end portion of one conductor part 31a and the looped irradiation position movement path 100 at the end portion of the other conductor part 31a in the direction in which the end portions of the adjacent conductor parts 31a are arranged. The movement path 100b may be a straight line (a common outside tangent) that touches the two looped movement paths 100. The irradiation of the laser beam is stopped in the irradiation position movement path 100b.

[0077] Thus, the laser beam is not irradiated between the looped movement path 100 of the irradiation position at the end portion of one conductor part 31a and the looped movement path 100 of the irradiation position at the end portion of the other conductor part 31a. In other words, the laser beam is not irradiated into the gap 31a1 between the end portions of the conductor parts 31a. Therefore, the insulating layer 31b of the segment 31, etc., can be prevented from being damaged by the laser beam.

[0078] Heating of the end portions of the conductor parts 31a is also performed in the moving paths 100. Therefore, even if the irradiation of the laser beam is stopped and restarted at positions separated from the outer edges of the end portions of the conductor parts 31a in the direction in which the end portions of the adjacent conductor parts 31a are arranged, the heating of the end portions of the conductor parts 31a is not suppressed. For example, in the direction in which the end portions of the adjacent conductor parts 31a are arranged, the position at which the irradiation of the laser beam is stopped can be set to be substantially at the center of the end portion of one conductor part 31a; and the position at which the irradiation of the laser beam is restarted can be set to be substantially at the center of the end portion of the other conductor part 31a.Therefore, even if the end portion of the conductor part 31a has a dimensional variation, a shape variation, a deformation, etc., and the dimensions of the gap 31a1 vary, the irradiation of the laser beam into the gap 31a1 can be effectively suppressed.

[0079] Also, as in Fig. 6, the irradiation of the laser beam into the gap 31a1 can be more effectively suppressed by keeping the shortest distance L between the outer edge of the laser spot 100a and the outer edge of the end portion of the conductor part 31a constant.

[0080] When the loop-shaped movement path 100 of the irradiation position has the same shape and the same size for each of the end portions of the adjacent conductor parts 31a, the control program for irradiating the laser beam can be simplified.

[0081] Also, if the irradiation position movement path 100b is a straight line (an external common tangent) that touches the two loop-shaped irradiation position movement paths 100, a linear movement from one irradiation position movement path 100 to the other irradiation position movement path 100 is possible. Therefore, the movement time from one irradiation position movement path 100 to the other irradiation position movement path 100 can be shortened, and even the tact time can be reduced.

[0082] The movement paths 100 and 100b of the irradiation position according to the embodiment will now be described in more detail.

[0083] Fig. 7A and Fig. 7B are schematic views showing the movement paths 100 and 100b of the irradiation position.

[0084] The laser beam is directed to the end portion of a conductor part 31a, and the center of the laser spot 100a is moved along the loop-shaped movement path 100 of the irradiation position.

[0085] As in Fig. 7A, when the irradiation position of the laser beam (the center of the laser spot 100a) is moved in a direction from an irradiation start position 200a of the laser beam at the end portion of one conductor part 31a toward the end portion of the other conductor part 31a (in the illustration of Fig. 7A, when the center of the laser spot 100a is moved counterclockwise), when the laser beam is initially irradiated, the center of the laser spot 100a is moved by one revolution from the laser beam irradiation start position 200a along the loop-shaped movement path 100 of the irradiation position. In other words, the irradiation position of the laser beam is shifted by 1 revolution from the laser beam irradiation start position 200a along the loop-shaped movement path 100 of the irradiation position. In this way, the movement of the center of the laser spot 100a along the loop-shaped movement path 100 of the irradiation position can smoothly transition to the movement along the linear movement path 100b of the irradiation position.

[0086] Then, the irradiation of the laser beam is stopped, and the center of the laser spot 100a, if the laser spot 100a is assumed to be formed, is moved along the linear movement path 100b of the irradiation position to an irradiation start position 201a of the laser beam at the end portion of the other guide part 31a.

[0087] Then, as in Fig. 7B, when the irradiation position of the laser beam reaches the irradiation start position 201a of the laser beam, the irradiation of the laser beam is restarted, and the center of the laser spot 100a is moved from the irradiation start position 201a of the laser beam in a direction away from the one guide part 31a. In the illustration of Fig. 7B, the center of the laser spot 100a is moved counterclockwise. In other words, the direction of movement of the laser spot 100a is the same in each of the end portions of the adjacent conductor parts 31a. Thus, the movement of the center of the laser spot 100a is uniform.

[0088] Furthermore, the center of the laser spot 100a is moved 1.5 turns from the laser beam irradiation start position 201a along the looped motion path 100 of the irradiation position. In other words, at the end portion of the other guide part 31a, the laser beam irradiation position is moved 1.5 turns along the motion path 100 of the irradiation position in the same direction as the motion direction of the irradiation position at the end portion of the one guide part 31a. Thus, the movement of the center of the laser spot 100a along the looped motion path 100 of the irradiation position can seamlessly transition into the movement along the linear motion path 100b of the irradiation position.

[0089] Then, the irradiation of the laser beam is stopped, and the center of the laser spot 100a, when the laser spot 100a is assumed to be formed, is moved along the linear movement path 100b of the irradiation position to an irradiation start position 200b of the laser beam at the end portion of the one guide part 31a.

[0090] Subsequently, the laser beam irradiation is resumed at the laser beam irradiation start position 200b, and the center of the laser spot 100a is moved from the laser beam irradiation start position 200b in a direction away from the other guide part 31a. Thus, the movement of the center of the laser spot 100a is smooth.

[0091] In addition, the center of the laser spot 100a is moved 1.5 revolutions from the laser beam starting position 200b along the loop-shaped motion path 100 of the irradiation position. Thus, the movement of the center of the laser spot 100a along the loop-shaped motion path 100 of the irradiation position can smoothly transition into the movement along the linear motion path 100b of the irradiation position.

[0092] Thereafter, the center of the laser spot 100a is moved by a similar method by 1.5 turns along the loop-shaped moving path 100 of the irradiation position at each of the end portions of the adjacent conductor parts 31a.

[0093] Fig. 8A and Fig. 8B are schematic views illustrating the movement paths 100 and 100b of the irradiation position according to another embodiment.

[0094] Also according to the embodiment as in Fig. As shown in Fig. 8A, the laser beam is irradiated onto the end portion of a conductor part 31a, and the center of the laser spot 100a is moved along the loop-shaped moving path 100 of the irradiation position.

[0095] However, according to the embodiment, at the initial irradiation of the laser beam, the irradiation position of the laser beam (the center of the laser spot 100a) is moved from the irradiation start position 200a of the laser beam at the end portion of one conductor part 31a in a direction away from the end portion of the other conductor part 31a. In the illustration of Fig. 8A, the center of the laser spot 100a is moved clockwise. In other words, the direction of movement of the center of the laser spot 100a is the opposite of the illustration in Fig. 7A.

[0096] In such a case, the center of the laser spot 100a is shifted by 1.5 revolutions from the laser beam start position 200a along the looped motion path 100 of the irradiation position. In other words, the irradiation position of the laser beam is shifted by 1.5 revolutions from the laser beam irradiation start position 200a along the motion path 100 of the irradiation position. In this way, the movement of the center of the laser spot 100a along the looped motion path 100 of the irradiation position can smoothly transition into the movement along the linear motion path 100b of the irradiation position.

[0097] Then, the irradiation of the laser beam is stopped, and the center of the laser spot 100a, when the laser spot 100a is assumed to be formed, is moved along the linear movement path 100b of the irradiation position to an irradiation start position 201b of the laser beam at the end portion of the other guide part 31a.

[0098] Then, as in Fig. 8B, when the irradiation position of the laser beam has reached the irradiation start position 201b of the laser beam, the irradiation of the laser beam is restarted, and the center of the laser spot 100a is moved from the irradiation start position 201b of the laser beam in a direction away from the one guide part 31a. In the illustration of Fig.8B, the center of the laser spot 100a is moved clockwise. In other words, the direction of movement of the laser spot 100a is the same in each of the end portions of the adjacent conductor parts 31a. Thus, the movement of the center of the laser spot 100a is uniform.

[0099] In addition, the center of the laser spot 100a is moved 1.5 revolutions from the laser beam starting position 201b along the loop-shaped motion path 100 of the irradiation position. Thus, the movement of the center of the laser spot 100a along the loop-shaped motion path 100 of the irradiation position can smoothly transition into the movement along the linear motion path 100b of the irradiation position.

[0100] In other words, according to the embodiment, the irradiation position of the laser beam at the end portion of the other guide part 31a is moved by 1.5 turns along the movement path 100 of the irradiation position in the same direction as the movement direction of the movement path 100 at the end portion of the one guide part 31a.

[0101] Then, the irradiation of the laser beam is stopped, and the center of the laser spot 100a, when the laser spot 100a is assumed to be formed, is moved along the linear movement path 100b of the irradiation position to the irradiation start position 200a of the laser beam at the end portion of the one guide part 31a.

[0102] Subsequently, the laser beam irradiation is resumed at the laser beam irradiation start position 200a, and the center of the laser spot 100a is moved from the laser beam irradiation start position 200a in a direction away from the other guide part 31a. Thus, the movement of the center of the laser spot 100a is smooth.

[0103] In addition, the center of the laser spot 100a is moved 1.5 revolutions from the laser beam starting position 200a along the loop-shaped motion path 100 of the irradiation position. Thus, the movement of the center of the laser spot 100a along the loop-shaped motion path 100 of the irradiation position can smoothly transition into the movement along the linear motion path 100b of the irradiation position.

[0104] Thereafter, the center of the laser spot 100a is moved by 1.5 turns along the loop-shaped moving path 100 of the irradiation position at each of the end portions of the adjacent conductor parts 31a by a similar procedure.

[0105] While certain embodiments of the inventions have been illustrated, these embodiments are presented only by way of example and are not intended to limit the scope of the invention. These novel embodiments may be embodied in a variety of other forms, and various omissions, substitutions, changes, etc., may be made without departing from the spirit of the inventions. These embodiments and their modifications are within the scope and spirit of the inventions, and are within the scope of the inventions described in the claims and their equivalents. The above embodiments may also be practiced in combination with one another. [List of reference symbols] 1 stator 2 core 3 coil 31 segments 31a Ladder section 31a1 gap 31b Insulating foil 100 movement path 100a laser point 100b Movement path 200a Irradiation start position 201a Starting position of irradiation 200b Start position of irradiation 201b Starting position of irradiation QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2018-20340 A

[0006] WO 2019 / 159737 A

[0006]

Claims

[1] A laser welding method for welding an end portion of a first wire-shaped member and an end portion of a second wire-shaped member by alternately irradiating the end portion of the first wire-shaped member and the end portion of the second wire-shaped member with a laser beam, the second wire-shaped member being adjacent to the first wire-shaped member, the laser welding method comprising: irradiating the laser beam along a first movement path at the end portion of the first wire-shaped member, the first movement path being loop-shaped; Stopping the irradiation of the laser beam and moving an irradiation position of the laser beam from the end portion of the first wire-shaped member to the end portion of the second wire-shaped member along a second movement path, the second movement path being linear; irradiating the laser beam along a third movement path at the end portion of the second wire-shaped member, the third movement path being loop-shaped; and Stopping the irradiation of the laser beam and moving the irradiation position of the laser beam from the end portion of the second wire-shaped element to the end portion of the first wire-shaped element along a fourth movement path, wherein the fourth movement path is linear, the second movement path touches the first and third movement paths, wherein the fourth movement path contacts the first and third movement paths at a location opposite the second movement path. [2] The laser welding method according to claim 1, wherein the first movement path has the same shape as the third movement path and the same size as the third movement path. [3] The laser welding method according to claim 1 or 2, wherein a shortest distance between an outer edge of a laser spot at the end portion of the first wire-shaped member and an outer edge of the end portion of the first wire-shaped member is constant. [4] The laser welding method according to any one of claims 1 to 3, wherein a shortest distance between an outer edge of a laser spot at the end portion of the second wire-shaped member and an outer edge of the end portion of the second wire-shaped member is constant. [5] The laser welding method according to any one of claims 1 to 4, wherein when the irradiation position of the laser beam is moved from an irradiation start position of the laser beam at the end portion of the first wire-shaped member in a direction toward the end portion of the second wire-shaped member when the laser beam is initially irradiated, the irradiation position of the laser beam is moved by 1 turn along the first moving path from the irradiation start position of the laser beam, and then the irradiation position of the laser beam is moved by 1.5 turns along the second moving path at the end portion of the second wire-shaped member in the same direction as a moving direction of the first moving path. [6] The laser welding method according to any one of claims 1 to 4, wherein when the irradiation position of the laser beam is moved from an irradiation start position of the laser beam at the end portion of the first wire-shaped member in a direction away from the end portion of the second wire-shaped member when the laser beam is initially irradiated, the irradiation position of the laser beam is moved by 1.5 turns along the first movement path from the irradiation start position of the laser beam, and then the irradiation position of the laser beam is moved by 1.5 turns along the second movement path at the end portion of the second wire-shaped member in the same direction as a movement direction of the first movement path. [7] A method of manufacturing a rotating electrical machine, the manufacturing method comprising: Arranging a coil in a plurality of slots, wherein the coil comprises a plurality of segments, wherein arranging the coil includes applying the laser welding method according to any one of claims 1 to 6 to weld end portions of conductor parts of the plurality of segments.

Images