Method for manufacturing stator and method for manufacturing motor

Abstract

In this method for manufacturing a stator (11), a protective jig (40) for protecting a protective glass (31b) provided to a laser head (31) is attached to a laser-welding device (20) for joining the ends (12a) of a segment coil (12) to each other. The protective jig (40) is provided with: a first partition part (43b) having a first long hole (46a); and a second partition part (47b) having a second long hole (47a). A protective space (S) is formed between the protective glass (31b) and the first partition part (43b). An air passage (R) is formed between the first partition part (43b) and the second partition part (47b). The protective jig (40) is provided with a nozzle (51) that generates an airflow in the air passage (R).

Description

Stator manufacturing method and motor manufacturing method

[0001] The present invention relates to a method for manufacturing a stator and a method for manufacturing a motor.

[0002] In recent years, rectangular wires with rectangular cross sections have been used as windings for the stators of automotive motors to increase the space factor. When rectangular wires are used as windings, a typical method is to first form multiple short segment coils from the wires, assemble them into a stator core, and then weld the ends of the segment coils together to form the coils.

[0003] JP2022-36296A discloses a method of laser welding these end portions together by irradiating a laser along a predetermined path from the end face side.

[0004] Conventional laser welding devices, which irradiate laser light from a laser irradiation port to weld the required areas, are provided with a laser head that incorporates a focusing lens that focuses the laser light, a protective glass that protects the focusing lens, etc. By providing the protective glass, even if welding by-products such as spatter and fumes are generated during welding, the spatter and the like are prevented from adhering to the focusing lens.

[0005] However, even if the protective glass can protect the focusing lens, etc., adhesion of spatter, etc. to the protective glass itself is unavoidable. If spatter, etc. adheres to the protective glass, the laser light passing through the protective glass is attenuated, resulting in a decrease in output, which in turn leads to a decrease in welding quality, an increase in maintenance costs due to the need to replace the protective glass more frequently, and a decrease in productivity.

[0006] An object of the present invention is to suppress adhesion of spatters and the like to a protective glass.

[0007] According to one aspect of the present invention, in a method for manufacturing a stator, the method includes a joining step of inserting a plurality of segment coils into a stator core and joining the ends of the segment coils together by laser welding, the joining step is performed by a laser welding device equipped with a laser head capable of irradiating the ends of the segment coils with laser light, and the laser welding device is equipped with a protective jig that protects a protective glass provided at the laser irradiation port of the laser head, the protective jig including a first partition having a first elongated hole through which the laser light passes and provided opposite the protective glass in the irradiation direction of the laser light, and a second partition having a second elongated hole through which the laser light passes and provided on the opposite side of the protective glass across the first partition, a protective space is formed between the protective glass and the first partition, an air passage is formed between the first partition and the second partition, and the protective jig is equipped with a nozzle that blows air into the air passage to generate an airflow.

[0008] FIG. 1 is a front view of a laser welding apparatus used in a joining step of a manufacturing method for a stator according to an embodiment of the present invention. FIG. 2 is a side view of the laser welding apparatus. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 3. FIG. 5 is a cross-sectional view taken along line E-E in FIG. 3. FIG. 6 is a cross-sectional view taken along line C-C in FIG. 3. FIG. 7 is a cross-sectional view taken along line F-F in FIG. 3. FIG. 8 is a diagram for explaining the procedure for attaching a protective jig. FIG. 9 is a cross-sectional view taken along line D-D in FIG. 2. FIG. 10 is a front view of a fixture for fixing workpieces to be welded.

[0009] Hereinafter, a method for manufacturing a stator and a method for manufacturing a motor according to an embodiment of the present invention will be described with reference to the drawings.

[0010] 1 and 2 show a laser welding apparatus 20 used in the manufacturing method of a stator. In the drawings, three mutually orthogonal axes, X, Y, and Z, are set, and the configuration of the laser welding apparatus 20 will be described assuming that the X axis extends in the horizontal front-rear direction, the Y axis extends in the horizontal lateral direction, and the Z axis extends in the vertical direction.

[0011] The laser welding apparatus 20 comprises a fixture 22 for fixing the workpiece 11, a moving part 29 for rotating and moving the workpiece 11 together with the fixture 22, a laser irradiator 30 for melting the required welding area 12a of the workpiece 11 with laser light, and a housing 21 for accommodating the fixture 22, the moving part 29 and the laser irradiator 30.

[0012] In the following, we will explain the case where the workpiece 11 fixed to the fixing device 22 is the stator 11 of a rotating electric machine used in electric vehicles, etc., and the area 12a requiring welding is the end 12a of a segment coil 12 attached to the stator 11.

[0013] The stator 11 is mainly composed of a stator core 13 and a plurality of segment coils 12 arranged in a plurality of slots (not shown) of the stator core 13. The segment coils 12 are formed from rectangular wires of a predetermined length with a substantially rectangular cross section, and more specifically, are twisted into a predetermined shape with complex curved portions so as to be inserted into the slots (not shown) of the stator core 13.

[0014] The multiple segment coils 12 are each inserted into a slot (not shown) formed along the axial direction on the inner periphery of the stator core 13 so that the end portions 12 a protrude upward from the stator 11 .

[0015] FIG. 10 shows a fixture 22 that supports, inside a housing 21, a stator 11 that includes a plurality of segment coils 12 and a stator core 13 to which the plurality of segment coils 12 are attached.

[0016] The fixture 22 is configured to be able to support the stator 11 so that the central axis of the stator 11 is aligned in the vertical direction (Z-axis direction).

[0017] Specifically, the fixing device 22 has a base plate 22a attached to the upper surface of the rotating table 24 described below, a core support plate 22c attached above the base plate 22a via a plurality of first supports 22b and on which the underside of the stator core 13 is placed, a core pressing plate 22e attached above the core support plate 22c via a plurality of second supports 22d and installed so as to sandwich the peripheral portion of the stator core 13 together with the core support plate 22c, and a gripping plate 23 attached above the core pressing plate 22e via a plurality of third supports 22f.

[0018] The stator core 13 is placed on the core support plate 22c so that the end 12a of the segment coil 12 protrudes upward from the top surface of the stator core 13, and is fixed to the fixing device 22 by clamping the peripheral portion between the core support plate 22c and the core pressing plate 22e.

[0019] As shown in Figures 4 and 9, the gripping plate 23 has multiple insertion holes formed at predetermined intervals in the radial and circumferential directions, through which the end portions 12a of multiple segment coils 12 protruding from above the stator core 13 are inserted.

[0020] The ends 12a of the plurality of segment coils 12 are inserted into insertion holes formed in the gripping plate 23, and are gripped by the gripping plate 23 in a state where they protrude upward from the upper surface of the gripping plate 23. In this way, the ends 12a of the plurality of segment coils 12 are positioned by the gripping plate 23 so that they are located at predetermined welding positions.

[0021] In other words, the gripping plate 23 is formed in a shape that can grip and fix all of the ends 12a of multiple segment coils 12 arranged at predetermined intervals in the radial and circumferential directions, as shown in Figure 9.

[0022] As shown in Figures 1 and 2, the housing 21 comprises a lower body 26 having mounting legs 26a attached to the lower part and surrounded by a peripheral wall 26b, a welding area 27 provided on the upper part of the lower body 26, and an upper body 28 provided on the upper part of the welding area 27 and having an operation panel 28a, a display 28b, etc. provided on the front side.

[0023] A back plate 27b that forms the back surface of the welding area portion 27 is erected on the back surface of the upper part of the lower body 26, and support columns 27a are erected on both sides of the front surface of the upper part of the lower body 26.

[0024] A translucent resin door 27c is attached to each support column 27a via a hinge 27d, and opening the door 27c makes it possible to replace or take in and out components provided in the welding area 27. In addition, in order to make the space in the welding area 27 visible, a side wall 27e that closes the gap between the back panel 27b and the support column 27a is formed of a translucent material.

[0025] Also provided within the housing 21 is a rotating table 24 to which the fixture 22 is attached.

[0026] 2, the rotating table 24 is a disk-shaped member attached to the upper end of a vertical shaft 24a that is pivotally supported within the lower body 26 and extends in the vertical direction (Z-axis direction), and its upper surface is a flat surface on which the base plate 22a of the fixture 22 is placed. The rotating table 24 is provided so as to be located near the boundary between the lower body 26 and the welding region 27.

[0027] 9 and 10, pins 24b used to position fixture 22 are provided facing upward on the top surface of turntable 24, and pin holes 22g through which pins 24b are inserted are formed in base plate 22a of fixture 22. Fixture 22 is installed at a predetermined position relative to turntable 24 by inserting pins 24b into pin holes 22g in base plate 22a.

[0028] The moving part 29, which moves the workpiece 11 together with the fixture 22, is composed of a motor 29 installed adjacent to the rotating table 24 inside the lower body 26, and a chain 29c connecting a sprocket 29b provided on the rotating shaft 29a of the motor 29 to a sprocket 24c provided on the vertical shaft 24a.

[0029] When the motor 29 is driven and the rotating shaft 29a rotates, the rotation is transmitted to the rotating table 24 via the chain 29c and the vertical shaft 24a, and the fixing device 22 placed on the rotating table 24 rotates together with the stator 11, which is the workpiece to be welded.

[0030] Furthermore, since the fixing device 22 is installed coaxially with the rotating table 24, by rotating the rotating table 24 using the motor 29, the welding-required areas 12a, i.e., the ends 12a of the segment coil 12, which are arranged at predetermined intervals in the circumferential direction on the upper surface of the fixing device 22, move circumferentially in the XY plane.

[0031] The laser irradiator 30 includes a laser head 31 that incorporates a laser oscillator (not shown), a fiber that serves as an optical path for transmitting the laser generated by the laser oscillator, and a focusing system component that focuses and irradiates the laser transmitted through the fiber.

[0032] The laser head 31 is attached above the fixture 22 , and the position of the laser head 31 in the vertical direction can be changed by the elevator unit 32 .

[0033] The lifting section 32 is mainly composed of a pair of guide rails 33 attached vertically to the back plate 27b of the welding area section 27, and a lifting member 34 attached to the guide rails 33 so as to be movable up and down.

[0034] Between the pair of guide rails 33, a rotating shaft 35 with a male thread formed on its surface is installed parallel to the guide rails 33, and a follower part 36 that is screwed onto the rotating shaft 35 via a ball screw is attached to the lifting member 34.

[0035] Additionally, a highly precisely controllable servo motor or the like is installed on the back panel 27b as a drive source 37 that rotationally drives the rotation shaft 35. When the rotation shaft 35 is rotated by the drive source 37, the follower 36 and the lifting member 34 to which the follower 36 is attached move up and down in the vertical direction (Z-axis direction).

[0036] The laser head 31 is a box-shaped body having a laser irradiation port 31a (FIGS. 3 and 4) on the bottom surface through which the laser light passes, and has light-gathering system components and a reflector and the like disposed inside. The laser head 31 is also provided with a protective glass 31b to cover the laser irradiation port 31a for protecting the light-gathering system components and the reflector. The laser head 31 is a ready-made product that is generally available on the market.

[0037] The laser irradiator 30 can change the irradiation direction of the laser light L by changing the reflection angle of the laser light inside the laser head 31 .

[0038] Therefore, as shown by the dotted arrow in Figure 4, the laser irradiator 30 can move the irradiation position in the diameter direction (X-axis direction) of the fixing device 22 by changing the angle of the laser light L irradiated from the laser irradiation port 31a formed on the underside of the laser head 31 through the protective glass 31b on the XZ plane, thereby sequentially welding the ends 12a of the segment coils 12, which are the areas that require welding and are arranged at predetermined intervals along the diameter direction.

[0039] As shown in FIGS. 3 and 4, the laser head 31 of the laser welding device 20 is provided with a protective jig 40 so as to cover the laser irradiation port 31a provided with the protective glass 31b.

[0040] The protective jig 40 comprises a first member 43 having a first partition portion 43b facing the protective glass 31b in the irradiation direction of the laser light L, a second member 44 having a second partition portion 44b arranged on the opposite side of the protective glass 31b across the first partition portion 43b, and a stay 45 for attaching the protective jig 40 to the laser head 31.

[0041] The first member 43 is a member having a first partition portion 43b in which a first through hole 43a is formed, and a pair of wall portions 43c extending along the Z-axis direction from both ends of the first partition portion 43b in the X-axis direction toward the second member 44, and the cross-sectional shape formed by the first partition portion 43b and the pair of wall portions 43c is approximately U-shaped as shown in Figure 4.

[0042] On the other hand, the second member 44 is a flat plate-like member having a second partition portion 44 b in which a second through hole 44 a is formed, and is attached to a pair of wall portions 43 c of the first member 43 .

[0043] 3 and 4, by attaching the second member 44 to the first member 43, a tube main body 42 having an air passage R therein, the cross section of which is approximately square in the Y-axis direction, is formed as the tubular member 41. In this way, the air passage R, the cross section of which is approximately square when viewed in the extension direction (when viewed in the Y-axis direction), is formed between the first partition portion 43b and the second partition portion 44b so as to intersect with the optical path of the laser light L. In other words, the tubular member 41 is provided with the first partition portion 43b and the second partition portion 44b on either side of the air passage R.

[0044] Furthermore, both ends of the first member 43 in the Y-axis direction are attached to the laser head 31 via stays 45 extending in the Z-axis direction, whereby the protective jig 40 is fixed to the laser head 31 so as to cover the laser irradiation port 31 a. By fixing the cylindrical member 41 to the laser head 31 via the stays 45 in this manner, a protective space S is formed between the protective glass 31 b and the first partition portion 43 b, as shown in Figures 3 and 4 .

[0045] The size of the protective space S formed between the protective glass 31b and the first partition portion 43b can be changed by changing the length of the stay 45 in the Z-axis direction.

[0046] The first through hole 43a and the second through hole 44a, which face each other across the air passage R, are provided at a position that overlaps with the laser irradiation port 31a in the vertical direction (Z-axis direction), i.e., at a position through which the laser light L irradiated from the laser head 31 passes.

[0047] The size of each through hole 43a, 44a is set such that, in the direction in which the angle of the laser light L irradiated from the laser head 31 is changed (the X-axis direction in Figure 4), the length F (Figure 6) in the X-axis direction of the second through hole 44a farther from the laser head 31 is larger than the length E (Figure 5) in the X-axis direction of the first through hole 43a closer to the laser head 31.

[0048] In this way, the first partition portion 43b and the second partition portion 44b, which are arranged opposite the protective glass 31b in the irradiation direction of the laser light L, are provided with the first through hole 43a and the second through hole 44a, respectively, through which the laser light L can pass, so that the first partition portion 43b and the second partition portion 44b do not obstruct the irradiation of the laser light L. Note that the shape of the first through hole 43a and the second through hole 44a may be any shape as long as the laser light L can pass through them, and may be rectangular, circular, or elliptical.

[0049] In addition, the protective jig 40 is provided with a nozzle 51 that blows air along an air passage R formed inside the cylindrical member 41 to generate an airflow, in order to prevent air containing spatter, etc. generated during welding from reaching the laser head 31 and causing the spatter, etc. to adhere to the protective glass 31b.

[0050] As shown in FIG. 3, the nozzle 51 is attached to the end of the tube body 42 so that the direction of the air flow formed in the air passage R is along the Y-axis direction, i.e., a direction perpendicular to the XZ plane which is the optical path of the laser light L.

[0051] Specifically, in order to generate a uniform air flow through the air passage R, which has a substantially rectangular cross section, the nozzle 51 has an outlet 51a formed in an elliptical shape, as shown in Fig. 4. The main body 51b of the nozzle 51 is fixed to an end of the first partition portion 43b. The shape of the outlet 51a is not limited to an elliptical shape and may be any shape as long as it can generate a uniform air flow through the air passage R. A plurality of outlets 51a may be provided.

[0052] Here, the air blown out from the nozzle 51 into the air passage R is sucked in through the first through hole 43a and the second through hole 44a due to the ejector effect, and in particular, air containing spatter, etc. is sucked in from the second through hole 44a which faces the space where welding of the end 12a of the segment coil 12 is performed.

[0053] If the air sucked in through the second through-hole 44a reaches the laser head 31 through the first through-hole 43a, spatters and the like contained in the air may adhere to the protective glass 31b.

[0054] Therefore, in this embodiment, in order to prevent air sucked in through the second through hole 44a from flowing out through the first through hole 43a, a pair of first adjustment plates 46, 46 that adjust the opening range of the first through hole 43a are provided in the first partition portion 43b, and a pair of second adjustment plates 47, 47 that adjust the opening range of the second through hole 44a are provided in the second partition portion 44b.

[0055] As shown in Figures 3 and 5, the pair of first adjustment plates 46, 46 adjust the opening range of the first through hole 43a in the Y-axis direction, i.e., the opening range of the first through hole 43a in the airflow direction of the air blown out from the nozzle 51 into the air passage R, and are attached with a predetermined gap W1 in the Y-axis direction.

[0056] The gap W1 thus formed between the pair of first adjustment plates 46, 46 becomes a first elongated hole 46a whose longitudinal direction is perpendicular to the airflow direction of the air blown out from the nozzle 51 into the air passage R (X-axis direction).

[0057] The first elongated hole 46a functions as a communication hole that connects the protective space S and the air passage R, and also functions as a through-hole in the first partition portion 43b through which the laser light L can pass.

[0058] As shown in Figures 3 and 6, the pair of second adjustment plates 47, 47 adjust the opening range of the second through hole 44a in the Y-axis direction, i.e., the opening range of the second through hole 44a in the airflow direction of the air blown out from the nozzle 51 into the air passage R, and are attached with a predetermined gap W2 in the Y-axis direction.

[0059] The gap W2 thus formed between the pair of second adjustment plates 47, 47 becomes a second elongated hole 47a whose longitudinal direction is perpendicular to the airflow direction of the air blown out from the nozzle 51 into the air passage R (X-axis direction).

[0060] The second long hole 47a functions as a communication hole connecting the air passage R and the space where welding of the end 12a of the segment coil 12 is performed, and also functions as a through hole in the second partition portion 47b through which laser light L can pass.

[0061] Furthermore, the positions of the pair of first adjustment plates 46, 46 attached to the first partition portion 43b and the pair of second adjustment plates 47, 47 attached to the second partition portion 47b are adjusted so that the first elongated hole 46a formed in the first partition portion 43b is located closer to the nozzle 51 than the second elongated hole 47a formed in the second partition portion 47b, i.e., upstream of the airflow of air blown from the nozzle 51 into the air passage R, as shown in Figure 3.

[0062] Even when the first long hole 46a is located closer to the nozzle 51 than the second long hole 47a in this way, the air is sucked in through both the first long hole 46a and the second long hole 47a due to the ejector effect of the air blown out from the nozzle 51 into the air passage R, but the air is sucked in through the first long hole 46a before the second long hole 47a.

[0063] Therefore, the air that is later sucked through the second elongated hole 47a is less likely to reach the first elongated hole 46a, through which air is sucked earlier.

[0064] As a result, even if the air sucked into the air passage R through the second elongated hole 47a contains spatters or the like, or if spatters or the like fly into the air passage R after passing through the second elongated hole 47a, the possibility of the spatters or the like traveling toward the laser head 31 through the first through-hole 43a is low, and the possibility of the spatters or the like adhering to the protective glass 31b is also low.

[0065] In order to prevent the air sucked through the second elongated hole 47a from flowing out into the protective space S through the first through-hole 43a, it is preferable to set the pressure in the protective space S to a positive pressure higher than atmospheric pressure. For example, the pressure in the protective space S is set to a positive pressure higher than atmospheric pressure by sending compressed air set to a positive pressure from an air compressor into the protective space S formed by attaching the protective jig 40 to the laser head 31 via the stay 45. Furthermore, the protective jig 40 may be provided with an air blower that constantly sends air into the protective space S.

[0066] By maintaining a positive pressure in the protective space S, air always flows into the air passage R through the first through-hole 43a, which prevents welding by-products such as fumes that have entered the air passage R through the second long hole 47a from reaching the first through-hole 43a, and as a result, prevents welding by-products from adhering to the protective glass 31b.

[0067] The size of the gap W3 (see Figures 6 and 8(c)) where the gap W1 formed between the pair of first adjustment plates 46, 46 and the gap W2 formed between the pair of second adjustment plates 47, 47 overlap in the irradiation direction (Z-axis direction) of the laser light L is set to be equal to or greater than the minimum width required for the passage of the laser light L. Furthermore, it is preferable that the size of the gap W3 be set to be equal to or slightly larger than the width d (Figure 3) in the Y-axis direction of the end 12a of the segment coil 12, which is the member to be welded and irradiated with the laser light L.

[0068] The size of these gaps W1, W2, W3 and the amount of deviation between the position of the first elongated hole 46a and the position of the second elongated hole 47a in the Y-axis direction can be adjusted arbitrarily by changing the positions of the pair of first adjustment plates 46, 46 and the pair of second adjustment plates 47, 47.

[0069] Furthermore, it is preferable that the size of the gap W1 formed between a pair of first adjustment plates 46, 46 and the size of the gap W2 formed between a pair of second adjustment plates 47, 47 are at least twice the size of the gap W3 where they overlap.

[0070] As described above, in this embodiment, the first partition 43b of the protective jig 40, which is provided opposite the protective glass 31b in the irradiation direction of the laser light L, has a first elongated hole 46a formed therein through which the laser light L passes, and the second partition 44b, which is provided on the opposite side of the first partition 43b from the protective glass 31b, has a second elongated hole 47a formed therein through which the laser light L passes after passing through the first elongated hole 46a. Furthermore, the first elongated hole 46a and the second elongated hole 47a are formed parallel to each other so that their longitudinal directions are perpendicular to the direction of the airflow generated in the air passage R.

[0071] In this embodiment, a protective space S is formed between the protective glass 31b and the first partition 43b, an air passage R is formed between the first partition 43b and the second partition 44b, and the protective jig 40 is provided with a nozzle 51 that blows air into the air passage R to generate an airflow. The first elongated hole 46a that connects the protective space S to the air passage R is provided closer to the nozzle 51 than the second elongated hole 47a that connects the air passage R to the space where welding of the end 12a of the segment coil 12 is performed.

[0072] Next, the procedure for assembling the protective jig 40 will be described with reference to FIG. 8 and other figures.

[0073] First, as shown in Figure 8 (a), stays 45 are attached to both sides of the first member 43 that constitutes the tube main body 42, and the stays 45 are attached to the laser head 31, so that the first through hole 43aa faces the laser irradiation port 31a, and the first member 43 is attached to the laser head 31.

[0074] Next, a pair of first adjusting plates 46, 46 are attached to the first partition portion 43b of the first member 43 so as to cover a portion of the first through-hole 43a. The pair of first adjusting plates 46, 46 are attached to the first partition portion 43b from below, i.e., from the side of the second member 44 that will be attached to the first member 43 later, with a predetermined gap W1 between them.

[0075] The pair of first adjustment plates 46, 46 are attached to the first partition portion 43b with a predetermined gap W1 between them, thereby forming a first elongated hole 46a that is partitioned by the first through hole 43a and the pair of first adjustment plates 46, 46. In other words, the first elongated hole 46a has a length in the short direction equal to the size of the gap W1 and a length in the long direction equal to the length E ( FIG. 5 ) of the first through hole 43a in the X-axis direction.

[0076] In this way, the pair of first adjustment plates 46, 46 are attached to the first partition portion 43b so that they are aligned along the direction in which the laser light L emitted from the laser head 31 changes angle (X-axis direction), that is, so that the longitudinal direction of the first long hole 46a is aligned along the X-axis direction.

[0077] 8B, the nozzle 51 is attached to one end of the first member 43. The nozzle 51 is attached so that the outlet 51a faces the other end of the first member 43.

[0078] 8(c), a flat second member 44 is attached to the lower end of the first member 43 to which the nozzle 51 is attached. Attaching the second member 44 to the first member 43 forms the tube main body 42 having an air passage R therein that has a substantially rectangular cross-sectional shape. Attaching the second member 44 to the first member 43 also brings the second through-hole 44a formed in the second partition portion 44b of the second member 44 into a position opposite the first through-hole 43a formed in the first partition portion 43b of the first member 43.

[0079] A pair of second adjustment plates 47, 47 are attached to the second member 44 attached to the first member 43 so as to partially cover the second through-holes 44a. The pair of second adjustment plates 47, 47 are attached to the second partition portion 44b from below, i.e., from the space side where the welding of the ends 12a of the segment coils 12 is performed, with a predetermined gap W2 between them.

[0080] The pair of second adjustment plates 47, 47 are attached to the second partition portion 44b with a predetermined gap W2 therebetween, thereby forming a second elongated hole 47a that is partitioned by the second through hole 44a and the pair of second adjustment plates 47, 47. In other words, the second elongated hole 47a has a length in the short direction equal to the size of the gap W2 and a length in the long direction equal to the length F ( FIG. 6 ) of the second through hole 44a in the X-axis direction.

[0081] In this way, the pair of second adjustment plates 47, 47 are attached to the second partition portion 44b so that the gap W2 is along the direction (X-axis direction) in which the laser light L emitted from the laser head 31 changes angle, that is, so that the longitudinal direction of the second long hole 47a is along the X-axis direction.

[0082] The cylindrical member 41 of the protective jig 40 attached to the laser head 31 through the above-described processes has the first elongated hole 46a and the second elongated hole 47a formed in it so as to extend in a direction perpendicular to the flow direction (Y-axis direction) of the air blown from the nozzle 51 into the air passage R and along a direction (X-axis direction) in which the angle of the laser light L can be changed. The first elongated hole 46a and the second elongated hole 47a are formed parallel to each other with the air passage R in between.

[0083] By forming the first elongated hole 46a and the second elongated hole 47a in the tubular member 41 in this manner, the optical path of the laser light L intersects with the air passage R extending horizontally (in the Y-axis direction) within the tubular member 41, and the laser light L passes through the tubular member 41.

[0084] Furthermore, since the nozzle 51 is attached to one end of the tubular member 41 so that the outlet 51a faces the inside of the tubular member 41, an air flow is generated in the air passage R inside the tubular member 41 with the nozzle 51 on the upstream side.

[0085] Furthermore, since the pair of first adjustment plates 46, 46 are attached to the first partition portion 43b from below, and the pair of second adjustment plates 47, 47 are attached to the second partition portion 44b from below, the attachment positions of each adjustment plate 46, 47 can be adjusted from below in a relatively open space, making adjustment work easy.

[0086] Next, a method for welding and joining the segment coil 12 using the laser welding device 20 to which the protective jig 40 having the above-described configuration is attached will be described.

[0087] When the workpiece is a stator 11 of a rotating electric machine, the ends 12a of multiple segment coils 12 pre-arranged on the stator core 13 are welded together by a laser welding device 20, so that the multiple segment coils 12 are electrically conductive.

[0088] In order to weld the ends 12 a of the segment coils 12 together, first, the stator core 13 , which is the workpiece to be welded and on which multiple segment coils 12 are arranged, is attached to a fixture 22 .

[0089] As shown in Figure 10, the stator core 13 is attached to the fixing device 22 by attaching a core pressing plate 22e from above the stator core 13 placed on the core support plate 22c, and sandwiching the peripheral portion of the stator core 13 between the core support plate 22c and the core pressing plate 22e.

[0090] Then, the end portions 12 a (parts that need to be welded) of the multiple segment coils 12 protruding from above the stator core 13 are gripped and fixed by a gripping plate 23 .

[0091] Next, the fixture 22 to which the stator 11 is attached is attached to the rotating table 24 .

[0092] As shown in Figures 1 and 2, the fixture 22 is attached to the rotating table 24 by opening the door 27c of the housing 21 and placing the base plate 22a of the fixture 22 on the rotating table 24 inside the housing 21 so that the positioning pin 24b on the rotating table 24 is inserted into the pin hole 22g on the base plate 22a (Figure 10).

[0093] Thereafter, the door 27c is closed and the welding operation is started. The welding operation is performed by operating the operation panel 28a on the upper body 28 (FIG. 1).

[0094] Here, when the workpiece is a stator 11 of a rotating electrical machine, there are a plurality of end portions 12a of the segment coil 12 to be laser welded, spaced at predetermined intervals in the radial and circumferential directions, as shown in FIG.

[0095] Therefore, welding using the laser welding device 20 involves sequentially welding multiple end portions 12a (areas requiring welding) arranged at a predetermined interval in the radial direction (X-axis direction), and then using the moving unit 29 to rotate the fixing device 22 together with the stator 11, and moving the next multiple end portions 12a (areas requiring welding) arranged adjacent to the end portion 12a whose welding has been completed in the circumferential direction (Y-axis direction) below the laser head 31.

[0096] Then, when the movement of the stator 11 by the moving unit 29 is completed, the plurality of end portions 12 a (points requiring welding) located below the laser head 31 are sequentially welded by the laser welding device 20 .

[0097] As shown by the dotted arrows in Figure 4, the laser irradiator 30 changes the angle of the laser light L irradiated from the laser head 31 without moving the laser head 31, and moves the irradiation position of the laser light L along the radial direction (X-axis direction) of the fixture 22, thereby sequentially welding multiple end parts 12a (places requiring welding) arranged at predetermined intervals in the radial direction (X-axis direction).

[0098] A protective jig 40 is attached to the laser head 31 so as to cover the laser irradiation port 31a. As described above, the protective jig 40 has a first elongated hole 46a and a second elongated hole 47a extending along the X-axis direction. Therefore, by passing the laser light L irradiated from the laser irradiation port 31a through the two elongated holes 46a, 47a, it is possible to sequentially weld the ends 12a of the segment coils 12 arranged at a predetermined interval in the X-axis direction.

[0099] Since the first elongated hole 46a and the second elongated hole 47a extend along the X-axis direction, the change in the irradiation position by changing the irradiation angle of the laser light L is limited to the X-axis direction. However, the laser welding device 20 is provided with a moving unit 29 that can move the areas 12a that need to be welded in a direction that intersects with the first elongated hole 46a and the second elongated hole 47a, so welding is possible at all of the areas 12a that need to be welded that exist on the XY plane.

[0100] Furthermore, when welding is performed by irradiating the laser light L, particles and droplets of molten metal are scattered around, so-called spatter occurs, and some of the spatter may be directed toward the laser head 31.

[0101] In this embodiment, the laser irradiation port 31a of the laser head 31 is covered by the protective jig 40, and therefore, the spatter is prevented from reaching the laser irradiation port 31a mainly by the areas of the cylindrical member 41 excluding the first long hole 46a and the second long hole 47a.

[0102] Here, the cylindrical member 41 of the protective jig 40 has a first elongated hole 46a and a second elongated hole 47a formed therethrough to allow the laser light L to pass therethrough, and therefore there is a risk that spatter will pass through both the first elongated hole 46a and the second elongated hole 47a and head toward the protective glass 31b.

[0103] However, as described above, the first elongated hole 46a and the second elongated hole 47a are parallel to each other and are arranged offset so that only a portion of the first elongated hole 46a and the second elongated hole 47a overlap, which further narrows the width W3 (FIG. 8C) through which the laser light L can pass. Therefore, the amount of spatter and the like directed toward the protective glass 31b is reduced compared to when a relatively large through-hole is formed to allow the laser light L to pass easily and the overlapping area of ​​these through-holes is relatively wide.

[0104] Furthermore, as shown by the solid arrows in Figure 3, when welding is performed, air is blown out from the nozzle 51, and an air flow caused by the blown out air is generated in the air passage R that the laser light L traverses within the cylindrical member 41.

[0105] In this way, when air is blown from the nozzle 51 into the air passage R inside the tubular member 41, the ejector effect causes the air to flow into the air passage R through the first elongated hole 46a and the second elongated hole 47a formed in the tubular member 41.

[0106] The first elongated hole 46a facing the protective glass 31b is located closer to the nozzle 51 than the second elongated hole 47a facing the location 12a to be welded, and the overlapping width W3 ( FIG. 8C ) of the first elongated hole 46a and the second elongated hole 47a is also narrow. Therefore, even if air containing spatter flows in through the second elongated hole 47a, the air is prevented from reaching the first elongated hole 46a, which is above the second elongated hole 47a, by the airflow in the air passage R and the first adjustment plate 46 that partitions the first elongated hole 46a. Therefore, the air containing spatter is prevented from flowing out to the protective glass 31b through the first elongated hole 46a.

[0107] In particular, since the first elongated hole 46a is shifted closer to the nozzle 51 than the second elongated hole 47a, i.e., further upstream of the air flow generated in the air passage R, the negative pressure generated near the first elongated hole 46a is greater than the negative pressure generated near the second elongated hole 47a due to the ejector effect, and as a result, the air flow flowing into the air passage R through the first elongated hole 46a is stronger than the air flow flowing into the air passage R through the second elongated hole 47a.

[0108] Therefore, even if spatter passes through the second elongated hole 47a and enters the air passage R, the spatter (black triangle in Figure 3) will be swept downstream of the air passage R by the flow of air that has flowed into the air passage R through the first elongated hole 46a, as shown by the solid arrow in Figure 3, and therefore the outflow of spatter and air containing spatter through the first elongated hole 46a to the protective glass 31b is prevented.

[0109] In addition, the flow of air flowing into the air passage R through the second elongated hole 47a can also push spatter that has passed through the second elongated hole 47a and entered the air passage R downstream of the air passage R, just like the flow of air flowing into the air passage R through the first elongated hole 46a.

[0110] In this way, by preventing spatter and the like from adhering to the protective glass 31b, the attenuation of the laser light L is also prevented, and as a result, deterioration in welding quality and productivity can be avoided.

[0111] Then, when welding is completed on the ends 12a (12a where welding is required) of all segment coils 12 arranged at a predetermined interval in the radial and circumferential directions, the ends 12a of the multiple segment coils 12 arranged in the stator core 13 become electrically conductive and become a single coil.

[0112] In this way, the joining process, which is one step in the manufacturing method of the stator 11, of joining the ends 12a of the segment coils 12 together by laser welding, is performed by a laser welding device 20 to which the protective jig 40 of the above-mentioned configuration is attached.

[0113] After the series of welding operations is completed, the stator core 13, which has become a coil, is removed from the fixture 22 and then incorporated into a motor (rotating electric machine) (not shown).

[0114] A motor (rotating electric machine) incorporating the stator 11 manufactured by the above-described manufacturing method includes the stator 11, a rotor (not shown) arranged coaxially with the stator 11, and a case (not shown) that houses the stator 11 and the rotor. The stator 11 and the rotor have a substantially annular shape, and the stator 11 is arranged to surround the outer periphery of the rotor. A rotating shaft is attached to the center of the rotor, and the rotating shaft is rotatably supported by the case via bearings.

[0115] The motor can be mounted on a vehicle, for example, and operate as an electric motor that receives power from a battery to rotate. Furthermore, when the rotor of the motor receives rotational energy from the drive wheels, the motor can function as a generator and charge the battery. The motor may be used as either an electric motor or a generator. Furthermore, the motor can be mounted on various devices other than vehicles (for example, to drive an air conditioner compressor).

[0116] Vehicles equipped with motors include, for example, BEVs (Battery Electric Vehicles), HEVs (Hybrid Electric Vehicles), and PHEVs (Plug-in Hybrid Electric Vehicles).

[0117] The above embodiment provides the following advantages.

[0118] In the manufacturing method of the stator 11, the joining process of joining the ends 12a of the segment coils 12 together by laser welding is performed by a laser welding device 20 equipped with a protective jig 40 that protects the protective glass 31b provided at the laser irradiation port 31a of the laser head 31.

[0119] The protective jig 40 is provided with a first partition 43b arranged opposite the protective glass 31b and a second partition 44b arranged on the opposite side of the protective glass 31b across the first partition 43b, so that the first partition 43b and the second partition 44b can prevent spatters and the like generated at the end 12a of the segment coil 12 (the area requiring welding) from reaching the protective glass 31b.

[0120] Furthermore, the cylindrical member 41 is formed with the first elongated hole 46a and the second elongated hole 47a through which the laser light L passes, and there is a risk that spatter and the like may pass through these elongated holes 46a, 47a and reach the protective glass 31b, but the first elongated hole 46a and the second elongated hole 47a are parallel to each other and are formed at offset positions, so the width through which the laser light L can pass is narrow. Therefore, compared to when a relatively large hole is formed, the amount of spatter and the like heading toward the protective glass 31b can be reduced.

[0121] Furthermore, the first elongated hole 46 a facing the protective glass 31 b is located closer to the nozzle 51 than the second elongated hole 47 a facing the location 12 a that requires welding. Therefore, when an air flow is generated in the air passage R that is traversed by the laser light L, the air flows into the air passage R through the first elongated hole 46 a due to the ejector effect, and this air flow sweeps away welding by-products such as spatter that have entered the air passage R from the second elongated hole 47 a to the downstream side of the air passage R.

[0122] This makes it possible to prevent spatters and the like from adhering to the protective glass 31b without complicating the structure.

[0123] Furthermore, by making the cylindrical member 41 divisible, it is possible to easily adjust the size and position of the first elongated hole 46a facing the protective glass 31b and the second elongated hole 47a facing the location 12a that requires welding. As a result, it becomes easier to adjust to changes in the irradiation angle of the laser light L, etc., thereby improving versatility.

[0124] Furthermore, if the irradiation angle of the laser light L were configured to be changeable along the first elongated hole 46a and the second elongated hole 47a that are parallel to each other, the welding direction would be limited to the longitudinal direction of the elongated holes 46a, 47a. However, the laser welding device 20 is provided with a moving unit 29 that can move the areas 12a that need to be welded in a direction that intersects the first elongated hole 46a and the second elongated hole 47a, so there is no restriction on the welding direction. As a result, it becomes possible to weld all of the areas 12a that need to be welded within a plane, thereby increasing the versatility of the laser welding device 20.

[0125] Furthermore, the irradiation angle of the laser light L can be changed, and the provision of a moving unit 29 for moving the areas 12a that require welding enables faster welding, so that even if the areas 12a that require welding are the ends 12a of a relatively large number of segment coils 12, as in the case where the workpiece is a stator 11 in which segment coils 12 are arranged in slots in a stator core 13, these ends 12a can be welded quickly. As a result, the manufacturing time for the stator 11 of a rotating electrical machine can be significantly reduced.

[0126] The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the different modified examples below.

[0127] In the above-described embodiment, the protective jig 40 is assembled by sequentially attaching the nozzle 51 and the second member 44 to the first member 43 attached to the laser head 31 via the stay 45. Alternatively, the protective jig 40 may be configured such that a unit in which the nozzle 51 and the second member 44 are previously attached to the first member 43 is attached to the laser head 31 via the stay 45. In this case, the protective jig 40 can be easily attached to an existing laser welding device if there is sufficient space for attachment.

[0128] In the above embodiment, the pair of first adjusting plates 46, 46 are attached to the first partition portion 43 b from below, and the pair of second adjusting plates 47, 47 are attached to the second partition portion 44 b from below. Alternatively, the pair of first adjusting plates 46, 46 may be attached to the first partition portion 43 b from above, and the pair of second adjusting plates 47, 47 may be attached to the second partition portion 44 b from above.

[0129] For example, both the pair of first adjustment plates 46, 46 and the pair of second adjustment plates 47, 47 may be attached to the outside of the tube main body 42, in which case it is easier to replace and adjust the position of the pair of first adjustment plates 46, 46 and the pair of second adjustment plates 47, 47 than when they are attached to the air passage R side.

[0130] In the above-described embodiment, the air passage R is formed inside the tubular main body 42 in which the second member 44 is attached to the first member 43. Alternatively, the air passage R may be formed inside a single tubular member having a substantially rectangular cross-sectional shape.

[0131] In the above-described embodiment, the pair of first adjusting plates 46, 46 and the pair of second adjusting plates 47, 47 are used to form the first elongated hole 46 a and the second elongated hole 47 a. Alternatively, the first elongated hole 46 a and the second elongated hole 47 a may be formed directly in the tube main body 42.

[0132] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0133] This application claims priority based on Japanese Patent Application No. 2024-089854, filed with the Japan Patent Office on June 3, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A method for manufacturing a stator, comprising a joining step of inserting a plurality of segment coils into a stator core and joining ends of the segment coils together by laser welding, wherein the joining step is performed by a laser welding device equipped with a laser head capable of irradiating the ends of the segment coils with laser light, and a protective jig is attached to the laser welding device to protect a protective glass provided at the laser irradiation port of the laser head, and the protective jig comprises: a first partition section having a first elongated hole through which the laser light passes and provided opposite the protective glass in the irradiation direction of the laser light; and a second partition section having a second elongated hole through which the laser light passes and provided on the opposite side of the protective glass with the first partition section in between, wherein a protective space is formed between the protective glass and the first partition section, and an air passage is formed between the first partition section and the second partition section, and the protective jig is provided with a nozzle that blows air into the air passage to generate an airflow.

2. A method for manufacturing a stator according to claim 1, wherein the pressure in the protective space is set to a positive pressure.

3. A method for manufacturing a stator as described in claim 1, wherein the protective jig has a tubular member with the air passage formed therein, the tubular member is provided with the first partition section and the second partition section on either side of the air passage, the first long hole and the second long hole are each formed so that their longitudinal directions are perpendicular to the direction of the air flow generated in the air passage, and the first long hole is provided on the nozzle side of the second long hole.

4. A method for manufacturing a stator as described in claim 1, wherein the laser head is capable of changing the irradiation position of the laser light irradiated from the laser irradiation port along the longitudinal direction of the first long hole and the second long hole, and the laser welding device further comprises a moving unit that moves the end of the segment coil in a direction intersecting the longitudinal direction of the first long hole and the second long hole.

5. A method for manufacturing a motor having a stator, wherein the stator is manufactured by the method for manufacturing a stator according to claim 1.

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