Manufacturing method of stator coil

Abstract

To provide a manufacturing method for a stator coil that can easily ensure the bonding strength between a segment coil and a connecting member.SOLUTION: A manufacturing method for a stator coil 20 has the steps for preparing segment coils 21,22 with exposed conductors 21a,22a at ends 21c,22c (step S1), forming a roughened area 31 on a portion of side surfaces 21d,22d of the exposed conductors 21a,22a with a surface roughness greater than other portions of the side surfaces 21d,22d (step S2), and connecting the plurality of segment coils 21,22 by press-fitting the exposed conductors 21a,22a into a connecting member 24 (step S5). Forming the roughened area 31 (step S2) is to form the roughened area 31 for a portion of the side surfaces 21d, 22d that are in contact with the connecting member 24 by the exposed conductors 21a, 22a being press-fitted into the connecting member 24.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a stator coil for a rotating electrical machine. [Background technology]

[0002] A rotating electric machine such as a motor or a generator includes a stator core and a stator coil wound around the stator core. The stator coil is configured by connecting a plurality of segment coils (for example, see Patent Document 1).

[0003] Patent document 1 discloses a stator coil including a plurality of segment coils and a connecting member having mating recesses formed at both ends, which connects the segment coils by fitting the segment coils into each of the mating recesses at both ends. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-126153 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the stator coil disclosed in Patent Document 1, if the actual contact area between the mating recess of the connecting member and the segment coil is small, the friction coefficient of the contact surface between the two is small. As a result, the pull-out load required to pull the segment coil out of the connecting member is small, and the joining strength between the segment coil and the connecting member may be reduced.

[0006] The present invention has been made in consideration of the above, and aims to provide a manufacturing method for a stator coil that can easily ensure the joint strength between the segment coil and the connecting member. [Means for solving the problem]

[0007] In order to solve the above problems, the manufacturing method of a stator coil of the present invention is a manufacturing method of a stator coil which comprises a plurality of segment coils and a cylindrical connecting member which connects the plurality of segment coils, and is wound around a stator core of a rotating electric machine, the manufacturing method comprising: preparing a segment coil in which the insulating coating on the end of the segment coil has been peeled off to expose the conductor at the end; forming a roughened area having a greater surface roughness than other parts of the side surface on a portion of the side surface of the exposed conductor; and connecting the plurality of segment coils by pressing the exposed conductor into the connecting member, wherein forming the roughened area is characterized in that the roughened area is formed on a portion of the side surface that comes into contact with the connecting member by pressing the exposed conductor into the connecting member.

[0008] With this configuration, the manufacturing method of the stator coil can increase the real contact area between the segment coil and the connecting member. Therefore, the manufacturing method of the stator coil can ensure the joint strength between the segment coil and the connecting member, and can suppress the electrical resistance of the stator coil. In addition, since the manufacturing method of the stator coil does not form a roughened area in a portion that does not contribute to increasing the real contact area, the roughened area can be formed in a short time by limiting it to only the highly effective roughened area. Therefore, the manufacturing method of the stator coil of the present invention can easily ensure the joint strength between the segment coil and the connecting member.

[0009] In a further preferred embodiment, the roughened region is formed by irradiating a part of the side surface that is in contact with the connecting member with a laser.

[0010] According to this embodiment, the manufacturing method of the stator coil can soften a portion of the side surface of the conductor that contacts the connecting member by annealing, making it easier to adhere to the connecting member. Therefore, the manufacturing method of the stator coil can further increase the true contact area between the segment coil and the connecting member. In addition, since the irradiation range can be easily controlled precisely with laser irradiation, the manufacturing method of the stator coil can easily form the roughened area accurately. Therefore, the manufacturing method of the stator coil of the present invention can more easily ensure the bonding strength between the segment coil and the connecting member.

[0011] In a further preferred embodiment, the conductor of the segment coil is a rectangular wire having a cross-sectional shape, and the roughened region is formed at a corner formed by the side surfaces of the rectangular wire.

[0012] According to this aspect, the manufacturing method of the stator coil can form a roughened region on the portion of the side surface of the exposed conductor that is surely in contact with the connecting member by pressing into the connecting member. Therefore, the manufacturing method of the stator coil can reliably form the roughened region only in the highly effective roughened region. Therefore, the manufacturing method of the stator coil of the present invention can more easily ensure the bonding strength between the segment coil and the connecting member.

[0013] In a further preferred embodiment, the conductor of the segment coil is a round wire having a circular cross-sectional shape, and the roughened regions are formed at intervals along the circumferential direction of the round wire on the side surface of the round wire.

[0014] According to this aspect, the manufacturing method of the stator coil can form a roughened region on the portion of the exposed side surface of the conductor that contacts the connecting member by pressing into the connecting member, while shortening the time required to form the roughened region. Therefore, the manufacturing method of the stator coil of the present invention can more easily ensure the bonding strength between the segment coil and the connecting member.

[0015] In a further preferred embodiment, the method for manufacturing a stator coil further comprises applying an adhesive to a non-roughened region that is another portion of the side surface.

[0016] According to this aspect, the manufacturing method of the stator coil can fill the gap between the segment coil and the connecting member with adhesive, thereby further improving the joining strength between the two. Effect of the Invention

[0017] According to the present invention, a manufacturing method for a stator coil can be provided that can easily ensure the joint strength between the segment coil and the connecting member. [Brief description of the drawings]

[0018] [Figure 1] FIG. [Diagram 2] FIG. 4 is a diagram for explaining how segment coils are connected. [Diagram 3] 4 is a flowchart showing a method for manufacturing the stator coil according to the present embodiment. [Figure 4] 13 is a diagram showing the analysis results of the surface pressure applied to the conductor of the segment coil pressed into the connecting member. [Diagram 5] 4A and 4B are diagrams showing roughened areas formed on a segment coil. [Figure 6] 13A to 13C are diagrams showing other examples of roughened areas formed on a segment coil. [Figure 7] 4A and 4B are diagrams showing the joined state of a segment coil and a connecting member. [Figure 8] FIG. 8 is an enlarged view of the main part shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components with the same reference numerals in each embodiment have the same functions in each embodiment unless otherwise specified, and description thereof will be omitted.

[0020] [Basic configuration of stator] Fig. 1 is an exploded perspective view of a stator 10 for a rotating electrical machine. Fig. 2 is a diagram illustrating how segment coils 21 and 22 are connected.

[0021] The stator 10 is combined with a rotor to form a rotating electric machine. The stator 10 of the present embodiment can be applied to a rotating electric machine mounted on an electric vehicle.

[0022] The stator 10 has a stator core 12 and a stator coil 20 wound around the stator core 12. The stator core 12 is roughly divided into a substantially annular core back 14 and a plurality of teeth 16 protruding radially inward from the inner peripheral surface of the core back 14. A slot 18, which is a space for accommodating a part of the stator coil 20, is formed between the teeth 16 adjacent in the circumferential direction. The stator core 12 may be, for example, a laminated steel plate formed by laminating a plurality of electromagnetic steel plates (e.g., silicon steel plates) in the thickness direction. The stator core 12 may be a dust core formed by press-molding magnetic particles coated with an insulating film.

[0023] The stator coil 20 is wound around the teeth 16 of the stator core 12. The connection and winding manner of the stator coil 20 may be appropriately selected according to the specifications of the rotating electric machine. The stator coil 20 may have U-phase, V-phase, and W-phase coils connected by star connection or delta connection. The stator coil 20 may be wound by distributed winding or concentrated winding.

[0024] The stator coil 20 includes a plurality of segment coils 21, 22 and a cylindrical connecting member 24 that connects the plurality of segment coils 21, 22. Although only the segment coils 21 and 22 are illustrated in FIG. 1, the stator coil 20 actually includes segment coils other than the segment coils 21 and 22.

[0025] The segment coils 21 and 22 are obtained by dividing the stator coil 20 into lengths that are easy to handle. The segment coil 21 shown in Fig. 1 extends in a substantially U-shape. The segment coil 22 shown in Fig. 1 extends in a substantially C-shape or substantially U-shape. However, the axial shapes of the segment coils 21 and 22 are not particularly limited.

[0026] The conductors 21a, 22a of the segment coils 21, 22 are rectangular wires having a cross-sectional shape perpendicular to their axis. In particular, the conductors 21a, 22a of the segment coils 21, 22 may be flat wires having a rectangular cross-sectional shape perpendicular to their axis. This allows the segment coils 21, 22 to improve the space factor of the stator coil 20 in the slot 18 and to be less susceptible to deformation such as twisting.

[0027] As shown in Fig. 2, the segment coils 21 and 22 include conductors 21a and 22a and insulating coatings 21b and 22b that cover the conductors 21a and 22a. The conductors 21a and 22a are made of a metal material such as copper (preferably oxygen-free copper). The insulating coatings 21b and 22b are made of an insulating material such as enamel.

[0028] The insulating coatings 21b, 22b are peeled off from the ends 21c, 22c of the segment coils 21, 22, exposing the conductors 21a, 22a. The segment coils 21, 22 are connected by pressing the ends 21c, 22c into the connecting member 24. That is, the segment coils 21, 22 are connected by pressing the exposed conductors 21a, 22a into the connecting member 24 from one end or the other end of the connecting member 24. The side surfaces 21d, 22d of the exposed conductors 21a, 22a contact the inner surface of the connecting member 24. The exposed conductors 21a, 22a are formed into a tapered shape.

[0029] The connecting member 24 is a tubular member having a through hole extending in the axial direction. The connecting member 24 is formed of a metal material such as copper (preferably oxygen-free copper). The connecting member 24 is a square tube having a rectangular cross section perpendicular to its axis. In particular, the connecting member 24 may be a flat square tube having a rectangular cross section perpendicular to its axis. The perimeter of the inner surface of the connecting member 24 may be equal to or less than the perimeter of the side surfaces 21d, 22d of the exposed conductors 21a, 22a, taking into account the tightening margin.

[0030] As described above, in the stator coil 20 constructed by press-fitting the segment coils 21, 22 into the connecting member 24, if the real contact area between the segment coils 21, 22 and the connecting member 24 is small, the friction coefficient of the contact surface between them is small. As a result, in the stator coil 20, the pull-out load for pulling the segment coils 21, 22 out of the connecting member 24 is small, and the joint strength between the segment coils 21, 22 and the connecting member 24 may decrease. Furthermore, if the real contact area between the segment coils 21, 22 and the connecting member 24 is small, the contact resistance between them increases. As a result, the electrical resistance of the stator coil 20 may increase, resulting in a large current loss.

[0031] Therefore, in this embodiment, in order to increase the actual contact area between the segment coils 21, 22 and the connecting member 24, the stator coil 20 is manufactured by a method as shown in FIG.

[0032] [Manufacturing method of stator coil] FIG. 3 is a flowchart showing a method for manufacturing the stator coil 20 of the present embodiment.

[0033] First, in the manufacturing method of the stator coil 20 of this embodiment, a preparation step is performed to prepare the segment coils 21, 22 with the conductors 21a, 22a at the ends 21c, 22c exposed (step S1). Specifically, a long coil material is cut to a desired length to form the segment coils 21, 22. Then, the insulating coatings 21b, 22b at the ends 21c, 22c of the segment coils 21, 22 are peeled off using a laser or the like.

[0034] Next, in the manufacturing method of the stator coil 20 of this embodiment, a forming step is performed to form roughened regions 31 on the ends 21c, 22c of the segment coils 21, 22 where the conductors 21a, 22a are exposed (step S2). Specifically, the roughened regions 31 having a larger surface roughness than the other parts of the side surfaces 21d, 22d are formed on parts of the side surfaces 21d, 22d of the exposed conductors 21a, 22a. This makes it possible for the manufacturing method of the stator coil 20 of this embodiment to increase the real contact area between the segment coils 21, 22 and the connecting member 24. Details of the forming step of the roughened regions 31 will be described later with reference to Figs. 4 to 8.

[0035] Next, in the manufacturing method of the stator coil 20 of this embodiment, a forming step is performed in which the segment coils 21, 22 are bent or curved to form them into a desired shape (step S3). This forming step is performed, for example, by pressing the segment coils 21, 22 against a dedicated die or bending them with a dedicated roller. This forming step may be performed between steps S1 and S2.

[0036] Next, in the manufacturing method of the stator coil 20 of this embodiment, an assembly process is performed in which the segment coil 21 formed into a desired shape is inserted into the slot 18 and assembled to the stator core 12 (step S4). The segment coil 21 inserted into the slot 18 is held by a dedicated jig to maintain the assembled state.

[0037] Next, in the manufacturing method of the stator coil 20 of this embodiment, a connecting step is performed to connect the multiple segment coils 21, 22 (step S5). Specifically, the exposed conductor 21a at the end 21c of the segment coil 21 is press-fitted into the connecting member 24. Then, the exposed conductor 22a at the end 22c of the segment coil 22 is press-fitted into the connecting member 24. The multiple segment coils 21, 22 are mechanically and electrically connected. This completes the manufacturing method of the stator coil 20 of this embodiment.

[0038] [Formation process of roughened area] Fig. 4 is a diagram showing an analysis result of the surface pressure applied to the conductor 21a of the segment coil 21 press-fitted into the connecting member 24. Fig. 5 is a diagram showing the roughened region 31 formed in the segment coil 21.

[0039] As described above, in the process of forming the roughened region 31, the roughened region 31 is formed on a portion of the side surfaces 21d, 22d of the exposed conductors 21a, 22a. Specifically, in the process of forming the roughened region 31, the roughened region 31 is formed on a portion of the side surfaces 21d, 22d that come into contact with the connecting member 24 as a result of the exposed conductors 21a, 22a being press-fitted into the connecting member 24. The roughened region 31 is a region having a surface roughness greater than that of other portions of the side surfaces 21d, 22d of the exposed conductors 21a, 22a. In this embodiment, the other portions of the side surfaces 21d, 22d of the conductors 21a, 22a where the roughened region 31 is not formed are also referred to as non-roughened regions 32.

[0040] The roughened region 31 can be formed by increasing the surface roughness by machining or by a chemical method such as etching. In the process of forming the roughened region 31 in this embodiment, a method of irradiating a part of the side surface 21d, 22d in contact with the connecting member 24 with a laser is adopted. The reason for adopting the laser irradiation is as follows. That is, when a part of the side surface 21d, 22d of the conductor 21a, 22a in contact with the connecting member 24 is irradiated with a laser, not only does the surface roughness of the part irradiated with the laser increase, but the part irradiated with the laser generates heat. Then, the part irradiated with the laser is softened by annealing, and when the part is pressed into the connecting member 24, the adhesion with the connecting member 24 is improved, and it becomes easy to adhere to the connecting member 24. This can further increase the real contact area between the segment coils 21, 22 and the connecting member 24. In addition, since the irradiation range of the laser irradiation can be controlled precisely, it is easier to accurately form the roughened region 31 than by machining and chemical methods. For this reason, in the step of forming roughened region 31 in this embodiment, roughened region 31 is formed by irradiating parts of side surfaces 21d, 22d that come into contact with connecting member 24 with a laser.

[0041] The surface roughness of the roughened region 31 may be, for example, 1.9 μm or more in arithmetic mean roughness Ra. The surface roughness of the non-roughened region 32 may be, for example, 0.63 μm or less in arithmetic mean roughness Ra. The hardness of the roughened region 31 may be, for example, 60 HV or more and 80 HV or less in Vickers hardness. The hardness of the non-roughened region 32 may be, for example, about 120 HV in Vickers hardness. By forming the roughened region 31 having such surface roughness and hardness, the manufacturing method of the stator coil 20 of this embodiment can facilitate adhesion between the segment coils 21, 22 and the connecting member 24, and therefore can reliably increase the true contact area between them.

[0042] In the process of forming the roughed region 31, it is also possible to form the roughed region 31 on the entire side surfaces 21d, 22d of the exposed conductors 21a, 22a. However, in this case, the time required for the process of forming the roughed region 31 increases. In particular, when laser irradiation is used in the process of forming the roughed region 31, the laser irradiation time and irradiation energy increase, so that there is a high possibility that the labor hours and power consumption in the manufacturing method of the stator coil 20 will increase significantly. In addition, as shown in FIG. 4, the parts of the side surfaces 21d, 22d that come into contact with the connecting member 24 when the exposed conductors 21a, 22a are pressed into the connecting member 24 are not the entire side surfaces 21d, 22d, but are parts of the side surfaces 21d, 22d. Therefore, even if the roughed region 31 is formed on the entire side surfaces 21d, 22d, the roughed region 31 formed on the other parts of the side surfaces 21d, 22d that do not come into contact with the connecting member 24 does not contribute to an increase in the real contact area between the segment coils 21, 22 and the connecting member 24, and is wasted. For this reason, in the process of forming roughened region 31 in this embodiment, roughened region 31 is formed on a portion of side surfaces 21d, 22d that come into contact with connecting member 24 as a result of exposed conductors 21a, 22a being press-fitted into connecting member 24.

[0043] FIG. 5 shows the conductor 21a exposed at the end 21c of the segment coil 21 viewed from the flatwise surface (wide surface) of the side surface 21d (left view of FIG. 5) and the edgewise surface (narrow surface) of the side surface 21d (right view of FIG. 5). The conductor 21a of the segment coil 21 is a rectangular wire having a cross section perpendicular to its axis. In this case, the roughened region 31 is formed at the corner 21e formed by the side surface 21d of the rectangular wire, as shown in FIG. 5. The corner 21e is longer from the central axis of the conductor 21a than the flat portion of the side surface 21d other than the corner 21e. The corner 21e is a part of the side surface 21d that comes into contact with the connecting member 24 when the exposed conductor 21a is pressed into the connecting member 24. By forming roughened region 31 at corner 21e, the process of forming roughened region 31 in this embodiment can form roughened region 31 in a portion of side surface 21d of exposed conductor 21a that is surely in contact with connecting member 24 by being pressed into connecting member 24. Therefore, the process of forming roughened region 31 in this embodiment can reliably form roughened region 31 limited to only highly effective roughened region 31.

[0044] The area of ​​roughened region 31 may be 50% or less of the total area of ​​side surface 21d of conductor 21a. The shape of roughened region 31 may be a rectangle, ellipse, or the like, with the longitudinal direction being the axial direction of exposed conductor 21a and the transverse direction being the circumferential direction of exposed conductor 21a.

[0045] FIG. 6 is a diagram showing another example of the roughened region 31 formed in the segment coil 21. As shown in FIG.

[0046] FIG. 6 shows the conductor 21a exposed at the end 21c of the segment coil 21 viewed from the side surface 21d (left view of FIG. 6) and the front view of the tip surface (right view of FIG. 6). As shown in FIG. 6, the conductor 21a of the segment coil 21 may be a round wire having a circular cross section perpendicular to its axis. In this case, the roughened regions 31 are formed at intervals along the circumferential direction of the round wire on the side surface 21d of the round wire that is the conductor 21a. As shown in FIG. 6, a plurality of roughened regions 31 may be formed so as to be spaced apart from each other at equal intervals in the circumferential direction of the round wire that is the conductor 21a. When the conductor 21a is a round wire, the entire side surface 21d of the conductor 21a may come into contact with the connecting member 24 by being pressed into the connecting member 24. However, in the forming process of the roughened region 31 of this embodiment, the roughened region 31 is formed on a part of the side surface 21d of the round wire that is the conductor 21a. As a result, the process of forming the roughened region 31 in this embodiment can shorten the time required for the process, while forming the roughened region 31 on the portion of the side surface 21d of the exposed conductor 21a that comes into contact with the connecting member 24 by pressing into the connecting member 24.

[0047] The area of ​​roughened region 31 shown in Fig. 6 may be 50% or less of the total area of ​​side surface 21d of conductor 21a, similar to roughened region 31 shown in Fig. 5. The shape of roughened region 31 shown in Fig. 6 may be a rectangle, ellipse, or the like, with the axial direction of exposed conductor 21a as the longitudinal direction and the circumferential direction of exposed conductor 21a as the transverse direction, similar to roughened region 31 shown in Fig. 5.

[0048] In the above description using Figs. 5 and 6, the segment coil 21 has been taken as an example, but the same applies to the segment coil 22.

[0049] Fig. 7 is a diagram showing a state in which the segment coils 21 and 22 are joined to the connecting member 24. Fig. 8 is an enlarged view of a main part A shown in Fig. 7.

[0050] 7 and 8 are cross-sectional photographs of the vicinity of the connecting member 24 of the stator coil 20 manufactured by the manufacturing method of the stator coil 20 of this embodiment. Fig. 8 shows an example of adhesion site B, which is a site where the segment coils 21, 22 and the connecting member 24 are adhered to each other. It can be seen that the manufacturing method of the stator coil 20 of this embodiment can generate adhesion site B as shown in Fig. 8, and therefore can ensure sufficient joint strength between the segment coil 21 and the connecting member 24.

[0051] As described above, the manufacturing method of the stator coil 20 of this embodiment is a manufacturing method of a stator coil that includes a plurality of segment coils 21, 22 and a cylindrical connecting member 24 that connects the plurality of segment coils 21, 22, and is wound around the stator core 12 of a rotating electric machine. The manufacturing method of the stator coil 20 of this embodiment includes the steps of preparing the segment coils 21, 22 in which the insulating coatings 21b, 22b of the ends 21c, 22c of the segment coils 21, 22 are peeled off to expose the conductors 21a, 22a of the ends 21c, 22c (step S1), forming a roughened region 31 having a surface roughness larger than that of the other parts of the side surfaces 21d, 22d on parts of the side surfaces 21d, 22d of the exposed conductors 21a, 22a (step S2), and connecting the plurality of segment coils 21, 22 by pressing the exposed conductors 21a, 22a into the connecting member 24 (step S5). Forming the roughened region 31 (step S2) involves forming the roughened region 31 on a portion of the side surfaces 21d, 22d that come into contact with the connecting member 24 as a result of the exposed conductors 21a, 22a being press-fitted into the connecting member 24.

[0052] As a result, the manufacturing method of the stator coil 20 of this embodiment can increase the true contact area between the segment coils 21, 22 and the connecting member 24. Therefore, the manufacturing method of the stator coil 20 of this embodiment can ensure the joint strength between the segment coils 21, 22 and the connecting member 24, and can suppress the electrical resistance of the stator coil 20. In addition, the manufacturing method of the stator coil 20 of this embodiment does not form the roughened region 31 in the part that does not contribute to increasing the true contact area, so that the roughened region 31 can be formed in a short time by limiting it to only the highly effective roughened region 31. Therefore, the manufacturing method of the stator coil 20 of this embodiment can easily ensure the joint strength between the segment coils 21, 22 and the connecting member 24.

[0053] An adhesive may be applied to the non-roughened region 32 of the stator coil 20. That is, the manufacturing method of the stator coil 20 of the present embodiment may include a coating step of applying an adhesive to the non-roughened region 32. As a result, the manufacturing method of the stator coil 20 of the present embodiment can fill the gaps between the segment coils 21, 22 and the connecting member 24 with the adhesive, thereby further improving the bonding strength between them.

[0054] The adhesive application step may be performed between step S4 and step S5 shown in FIG. 3. The adhesive may be a conductive adhesive or a non-conductive adhesive. The adhesive may be, for example, an epoxy resin adhesive. In this case, the manufacturing method of the stator coil 20 of the present embodiment may include a curing step of heating at least the vicinity of the connecting member 24 of the stator coil 20 to cure the adhesive after step S5 shown in FIG. 3.

[0055] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention described in the claims. In the present invention, the configuration of one embodiment can be added to the configuration of another embodiment, the configuration of one embodiment can be replaced with the configuration of another embodiment, or a part of the configuration of one embodiment can be deleted. [Explanation of symbols]

[0056] 10: stator; 12: stator core; 20: stator coil; 21, 22: segment coil; 21a, 22a: conductor; 21b, 22b: insulating coating; 21c, 22c: end portion; 21d, 22d: side surface; 21e: corner portion; 31: roughened region; 32: non-roughened region; 24: connecting member

Claims

1. A method for manufacturing a stator coil, the stator coil being wound around a stator core of a rotating electric machine, includes a plurality of segment coils and a cylindrical connecting member that connects the plurality of segment coils, the method comprising the steps of: Preparing the segment coil in which an insulating coating at an end of the segment coil is peeled off to expose a conductor at the end; forming a roughened region on a portion of a side surface of the exposed conductor, the roughened region having a surface roughness greater than that of other portions of the side surface; and connecting the plurality of segment coils by pressing the exposed conductor into the connecting member. forming the roughened region by irradiating a part of the side surface that is in contact with the connecting member by press-fitting the exposed conductor into the connecting member with a laser, The roughened region is The conductor has a rectangular or elliptical shape with the axial direction of the exposed conductor as the longitudinal direction and the circumferential direction of the exposed conductor as the short side direction, and is formed at intervals along the circumferential direction of the exposed conductor, on a part of the side surface that contacts the connecting member, The material is annealed by the irradiation of the laser and adheres to the connecting member when it is pressed into the connecting member. A method for manufacturing a stator coil comprising the steps of:

2. The exposed side surface of the conductor has the roughened region and a non-roughened region which is the other portion where the roughened region is not formed, The surface roughness of the roughened region is 1.9 μm or more in arithmetic mean roughness, The surface roughness of the non-roughened region is 0.63 μm or less in terms of the arithmetic mean roughness, The roughened region has a Vickers hardness of 60 HV or more and 80 HV or less, The non-roughened region has a Vickers hardness of 120 HV. The method for manufacturing a stator coil according to claim 1 .

3. The conductor of the segment coil is a rectangular wire having a cross-sectional shape, The roughened region is formed at a corner formed by the side surface of the rectangular wire. The method for manufacturing a stator coil according to claim 2 .

4. The conductor of the segment coil is a round wire having a circular cross-sectional shape, The roughened regions are formed on the side surfaces of the round wire at equal intervals along the circumferential direction of the round wire. The method for manufacturing a stator coil according to claim 2 .

5. applying an adhesive to the non-roughened area. The method for manufacturing a stator coil according to claim 2 .

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