Conductor forming method

Abstract

To provide a conductor formation method capable of suppressing an expansion in a width direction of a top point of a coil end part, and capable of being wound in a smaller diameter.SOLUTION: A conductor formation method for forming a conductor having a convex-shaped coil end part and a linear part connected to both ends of the coil end part by folding a conductor wire, comprises: a folding step of folding the conductor wire by using a portion corresponding to a top point of the coil end part of the conductor as a support point; and a skew step of forming the coil end part by relatively moving one side conductor wire to be folded in a direction crossing an extension direction of the linear part with respect to the other side conductor wire to be folded by using a portion corresponding to a boundary part of the coil end part of the conductor and the linear part as a support point after the start of the folding step.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] The present invention relates to a conductor forming method. [Background technology]

[0002] Conventionally, a conductor forming method is known in which a straight conductor wire is folded back to form a conductor having multiple straight sections and a mountain-shaped coil end section that connects both ends of adjacent straight sections (see, for example, Patent Document 1).

[0003] The conductor forming method described above involves first bending a straight conductor wire diagonally to form a slanted portion, and then folding the conductor wire back 180 degrees using the center of the slanted portion as a fulcrum to form a mountain-shaped coil end portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-058076 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, electric vehicles (BEVs: Battery Electric Vehicles) that are not equipped with internal combustion engines but are driven solely by rotating electric machines have become known. Generally, electric vehicles are equipped with rotating electric machines that are smaller than those in hybrid electric vehicles (HEVs: Hybrid Electric Vehicles). In order to reduce the size of rotating electric machines, it is necessary to reduce the diameter of the stator, and measures to achieve this are being sought.

[0006] In the above-described conventional technology, the coil end portion of the conductor wire is bent obliquely, and then the coil end portion is formed by folding back 180 degrees around the center of the oblique portion. However, this method results in a wide apex of the coil end portion after formation. Therefore, when a long strip-shaped coil is formed using this method, adjacent coil end portions along the length of the strip-shaped coil interfere with each other during winding. This makes it difficult to wind the strip-shaped coil to a small diameter so that it can be mounted on a small-diameter stator core.

[0007] An object of the present invention is to provide a conductor shaping method that can suppress the widthwise expansion of the apex of the coil end portion and enable winding with a smaller diameter. [Means for solving the problem]

[0008] (1) A conductor shaping method according to the present invention is a conductor shaping method for shaping a conductor (e.g., conductor 100 described later) having a mountain-shaped coil end portion (e.g., coil end portion 102 described later) and straight portions (e.g., straight portions 101 described later) connected to both ends of the coil end portion by folding back a conductor wire (e.g., conductor wire 1 described later), the method including a folding back step of folding back the conductor wire at a position corresponding to a vertex (e.g., vertex 102b described later) of the coil end portion of the conductor as a fulcrum. and a slanting process in which, after the start of the folding process, the conductor wire on one side to be folded is moved relative to the conductor wire on the other side to be folded in a direction (e.g., X1 direction described later) intersecting the extension direction of the straight portion (e.g., Y direction described later) using a portion of the conductor corresponding to a boundary (e.g., boundary 103 described later) between the coil end portion and the straight portion as a fulcrum, and the conductor wire is slanted around the vertex, thereby forming the coil end portion.

[0009] (2) In the conductor forming method described in (1) above, the inclined step is performed after the start of the folding step in a state where the conductor wire on one side to be folded back and the conductor wire on the other side to be folded back do not completely overlap each other.

[0010] (3) In the conductor forming method described in (1) or (2) above, the folding process and the oblique process are repeated multiple times for multiple conductor wires arranged in parallel at regular intervals, thereby forming the coil end portions at both ends of the straight portion in the extension direction, and forming the strip-shaped conductor (for example, the strip-shaped coil described below).

[0011] (4) In the conductor shaping method described in (3) above, the folding back step includes at least one step of folding back the plurality of conductor wires in a direction opposite to the folding direction of the previous folding back step. [Effects of the Invention]

[0012] According to the above (1), after the conductor wire folding process is started, the conductor wire is angled to form the coil end portion, which can prevent the apex of the formed coil end portion from expanding in the width direction, and therefore the conductor formed in this way can be wound with a smaller diameter.

[0013] According to (2) above, the conductor wires are made to slant before they completely overlap each other after the start of the folding process, so that a guide jig for forming a starting point for folding can be inserted before the slant starts.

[0014] According to (3) above, the widthwise expansion of the apex of the coil end portion is suppressed, and a band-shaped coil that can be wound with a small diameter is obtained.

[0015] According to the above (4), interference between layers can be avoided at the layer change portion of the wound strip-shaped conductor. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a front view showing an example of a conductor formed by the conductor forming method of the present embodiment. [Figure 2] FIG. 2 is a plan view showing a stator on which conductors are mounted. [Figure 3] 10A to 10C are diagrams illustrating a method for forming a U-shaped conductor wire. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 10 is a front view showing the state in which the conductor wires are overlapped. [Figure 6] 1 is a perspective view showing an example of a conductor shaping device for carrying out the conductor shaping method of the present embodiment. [Figure 7] FIG. [Figure 8] FIG. 2 is a perspective view showing a part of the gripping device before gripping the conductor wire. [Figure 9] FIG. 10 is a perspective view showing a part of the gripping device after gripping the conductor wire. [Figure 10] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 11] FIG. [Figure 12] FIG. [Figure 13] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 14] 10 is a side view showing a state in which the conductor wire is bent with the guide jig sandwiched therebetween. FIG. [Figure 15] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 16] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 17] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 18] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 19] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 20] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 21] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 22] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 23] FIG. 4 is an enlarged view showing a coil end portion of the conductor after forming. [Figure 24] FIG. 4 is a plan view showing a coil end portion of the conductor after forming. [Figure 25] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 26] 1A to 1C are diagrams illustrating a conductor shaping method using a conductor shaping device. [Figure 27] FIG. 2 is a plan view schematically showing a conductor having a layer change portion. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 shows an example of a conductor 100 formed by the conductor forming method of this embodiment. The conductor 100 is formed by bending a plurality of conductor wires 1. The conductor 100 of this embodiment is a strip-shaped coil made of six conductor wires 1 and formed into a long strip in one direction (the X direction in Fig. 1).

[0018] Here, the directions shown in the figures are defined as follows: The X direction is the length direction of the conductor 100. This X direction corresponds to the width direction of the conductor wire 1 that constitutes the conductor 100. The Y direction is the width direction of the conductor 100. This Y direction corresponds to the extension direction of the straight portions 101 of the conductor 100 and also corresponds to the length direction of the conductor wire 1. The Z direction is the thickness direction of the conductor 100. This Z direction corresponds to the thickness direction of the conductor wire 1. The X, Y, and Z directions in each figure correspond to the X, Y, and Z directions of the conductor 100, respectively.

[0019] The conductor 100 has a plurality of straight portions 101 arranged in parallel at regular intervals in the longitudinal direction, and a plurality of coil end portions 102 arranged on both end sides of each straight portion 101 in the extension direction. The straight portions 101 extend along the width direction of the conductor 100. The coil end portions 102 connect one end and the other end of every fifth straight portion 101, 101, alternately in a mountain shape along the longitudinal direction of the conductor 100.

[0020] The coil end portion 102 is formed in a mountain shape having an inclined portion 102a extending obliquely from a boundary portion 103 with the straight portion 101, and an apex 102b where the tips of the inclined portions 102a, 102a connected to the two straight portions 101, 101 are connected. In the conductor 100, the straight portions 101, 101 formed by the two legs 12, 12 of the outer conductor wire 1 of each double-structure conductor wire 1, 1 are arranged every sixth line in the longitudinal direction of the conductor 100, and the straight portions 101, 101 formed by the two legs 12, 12 of the inner conductor wire 1 are arranged every fifth line in the longitudinal direction of the conductor 100.

[0021] As shown in FIG. 2, the conductor 100 is mounted on a stator core 31 to form a stator 3 of a rotating electric machine. The stator core 31 has a plurality of teeth 33 that protrude radially toward an axial hole 32 that penetrates the stator core 31 in the axial direction (a direction perpendicular to the plane of FIG. 2). A plurality of slots 34 that open toward the axial hole 32 are formed between adjacent teeth 33 in the circumferential direction. The conductor 100 is mounted so as to wrap around the stator core 31 multiple times by sequentially inserting the straight portions 101 into the slots 34. The coil end portions 102 of the conductor 100 protrude outward on both axial sides of the stator core 31.

[0022] The conductor wire 1 constituting the conductor 100 is a continuous wire that continues uninterrupted in the longitudinal direction of the conductor 100. As shown in Fig. 3, the straight conductor wire 1 is bent and shaped approximately at the center by a drawing tool 300. As a result, the conductor wire 1 is shaped into a U-shape having one U-shaped portion 11 and a pair of straight leg portions 12, 12.

[0023] As shown in FIG. 4, each conductor wire 1 is composed of a plurality of flat wires 1a. The flat wires 1a are metal wires such as copper wires having a substantially rectangular cross section. The surfaces of the flat wires 1a are covered with a resin insulating coating (not shown). The conductor wire 1 of this embodiment is a divided wire in which two flat wires 1a, 1a are arranged in parallel in the width direction of the conductor wire 1 so that they are in close contact with each other. The conductor wire 1 is bent by the drawing tool 300 in the width direction of the conductor wire 1, which is the parallel direction of the flat wires 1a, 1a.

[0024] As shown in Fig. 5, each U-shaped conductor wire 1 is doubled up with two wires arranged on the inside and two wires on the outside, with the U-shaped portions 11 aligned on the same side. Three pairs of doubled conductor wires 1, 1 are similarly stacked, shifted in the width direction, so that the twelve legs 12 are parallel to each other at regular intervals. This forms a conductor wire group 10 consisting of six U-shaped conductor wires 1. The conductor wire group 10 is formed into a conductor 100 using a conductor shaping device 200 shown in Fig. 6.

[0025] Fig. 6 shows an overview of the configuration of the main parts of a conductor shaping apparatus 200 according to one embodiment. The conductor shaping apparatus 200 includes at least four gripping devices 210A, 210B, 210C, and 210D. The gripping devices 210A, 210B, 210C, and 210D are configured to be able to grip and release the twelve leg portions 12 of the conductor wire group 10 at once. Since the four gripping devices 210A, 210B, 210C, and 210D have the same configuration for gripping and releasing, the configuration of one gripping device 210 will be described with reference to Figs. 7 to 9.

[0026] 7, the gripping device 210 has a rectangular parallelepiped shape formed long across the twelve legs 12 arranged on the conductor wire group 10. The gripping device 210 has a fixed block 211 extending along the length of the gripping device 210 and twelve movable blocks 212.

[0027] As shown in FIGS. 8 and 9 , the fixed block 211 has twelve grooves 211a for accommodating the twelve leg portions 12 of the wire conductor group 10. The twelve movable blocks 212 are accommodated in the grooves 211a of the fixed block 211 so as to be movable along the X direction in the figure, leaving gaps G into which the respective leg portions 12 can fit. The gripping device 210 simultaneously moves all of the movable blocks 212 in the grooves 211a in the directions indicated by the white arrows in FIG. 8 by driving a drive mechanism (not shown). As a result, the gripping device 210 clamps and grips the leg portions 12 of the wire conductor group 10 that fit into each gap G between the fixed block 211 and the movable block 212. The gripping direction of the leg portions 12 by the gripping device 210 is the parallel direction of the two rectangular wires 1a, 1a that make up the wire conductor 1. Therefore, the gripping device 210 grips the leg portion 12 of the conductor wire 1 by pinching the conductor wire 1 in the width direction.

[0028] The four gripping devices 210A, 210B, 210C, and 210D are arranged parallel to one another and spaced apart in the length direction (Y direction) of the conductor wire group 10 on the same side in the thickness direction (Z direction) of the conductor wire group 10. The conductor shaping device 200 shown in FIG. 6 shows the initial position of the shaping process. At this time, the gripping device 210A is arranged near each U-shaped portion 11 of the conductor wire group 10. The gripping device 210B is arranged at a predetermined distance from the gripping device 210A, farther from each U-shaped portion 11 of the conductor wire group 10 than the gripping device 210A. The gripping device 210C is arranged at a predetermined distance from the gripping device 210B, farther from each U-shaped portion 11 of the conductor wire group 10 than the gripping device 210B. The gripping device 210D is disposed at a predetermined distance from the gripping device 210C, on the side farther from the U-shaped portions 11 of the conductor wire group 10 than the gripping device 210C.

[0029] As shown in FIG. 6, there is an equal distance L between the side edge E1 of the gripping device 210A and the side edge E2 of the gripping device 210B, and between the side edge E1 of the gripping device 210C and the side edge E2 of the gripping device 210D. The side edges E1 and E2 are two side edges of the gripping devices 210A, 210B, 210C, and 210D that are arranged parallel to the plane that grips the leg portion 12. In the gripping devices 210A, 210B, 210C, and 210D, the side edge E1 is the side edge closer to the U-shaped portion 11 of the conductor wire group 10, and the side edge E2 is the side edge farther from the U-shaped portion 11 of the conductor wire group 10. The distance L is substantially the same as the length L of the straight portion 101 of the conductor 100 shown in FIG. 1 in the extension direction.

[0030] The region of the wire conductor group 10 between the side edge E2 of the gripping device 210A and the side edge E1 of the gripping device 210B, and the region between the side edge E1 of the gripping device 210C and the side edge E2 of the gripping device 210D each constitute a straight portion forming region 10A for forming the straight portion 101 of the conductor 100. Therefore, the gripping devices 210A and 210B and the gripping devices 210C and 210D each grip 12 leg portions 12 within the straight portion forming region 10A of the wire conductor group 10. In the leg portions 12 of the wire conductor group 10 shown in FIG. 6, the straight portion forming region 10A is indicated by an outline.

[0031] The region of the conductor wire group 10 between the side edge E2 of the gripping device 210B and the side edge E1 of the gripping device 210C constitutes a coil end portion forming region 10B for forming the coil end portion 102 of the conductor 100. In the leg portion 12 of the conductor wire group 10 shown in FIG. 6, the coil end portion forming region 10B is indicated by hatching.

[0032] The straight portion forming regions 10A and the coil end portion forming regions 10B are alternately arranged from the U-shaped portion 11 side of the conductor wire group 10 along the length direction (Y direction) of the leg portion 12.

[0033] Of the four gripping devices 210A, 210B, 210C, and 210D, the two gripping devices 210A and 210B closest to the U-shaped portion 11 of the conductor wire group 10 are provided so as to be rotatable in forward and reverse directions about an imaginary folding line 220 shown in FIG. 6 as an axis while maintaining the distance L by being driven by a rotation mechanism (not shown). The folding line 220 is set at an intermediate position between the gripping devices 210B and 210C along the X direction in FIG. 6. This intermediate position corresponds to the position of the vertex 102b of the coil end portion 102 after the conductor wire group 10 has been folded. The folding line 220 is oriented in a direction perpendicular to the longitudinal direction of the leg portion 12 and parallel to the longitudinal direction of the four gripping devices 210A, 210B, 210C, and 210D. The holding devices 210A and 210B holding the leg portions 12 of the conductor wire group 10 rotate about the folding line 220 as an axis, whereby the conductor wire group 10 is folded back at the center of the coil end portion forming region 10B between the holding devices 210B and 210C. In this way, the folding back process is performed.

[0034] The gripping devices 210A and 210B are arranged to be movable in parallel relative to the gripping devices 210C and 210D along the X direction in FIG. 6 while maintaining a distance L by driving a tilting mechanism (not shown). In the conductor shaping device 200 of this embodiment, the gripping devices 210C and 210D are arranged to be immovable in the X direction, and the gripping devices 210A and 210B are arranged to be movable in parallel in the X direction. However, the gripping devices 210A and 210B may be arranged to be immovable in the X direction, and the gripping devices 210C and 210D may be arranged to be movable in parallel in the X direction. Furthermore, the gripping devices 210A and 210B and the gripping devices 210C and 210D may be arranged to be movable in parallel in opposite directions. The holding devices 210A and 210B holding the leg portions 12 of the conductor wire group 10 move parallel to the X direction relative to the holding devices 210C and 210D, whereby the coil end portion forming region 10B of the conductor wire group 10 between the holding devices 210B and 210C is bent so as to be inclined obliquely with respect to the longitudinal direction of the leg portions 12. This completes the oblique movement process.

[0035] Next, a method for shaping the conductor 100 from the conductor wire group 10 using the conductor shaping apparatus 200 will be described with reference to FIGS. 6 and 10 to 22. FIG.

[0036] First, as shown in Fig. 6, the conductor shaping device 200 grips the twelve leg portions 12 of the conductor wire group 10 using four gripping devices 210A, 210B, 210C, and 210D (gripping process). Thereafter, the gripping devices 210A and 210B are driven by a rotation mechanism (not shown) to rotate in the R1 direction around the folding line 220 as an axis, as shown in Fig. 10. This initiates the folding process for the coil end portion forming region 10B of the conductor wire group 10 that is closest to the U-shaped portion 11.

[0037] Although not shown in Fig. 10, in the folding back process, before the inclined feeding process described below is started, a guide jig 230 is used as shown in Figs. 11 and 12. As shown in Fig. 12, the guide jig 230 is formed in a substantially triangular wedge shape inclined at an angle of about 5° when viewed from the side. The guide jig 230 is inserted between the conductor wire group 10 on one side (the conductor wire group 10 held by the gripping devices 210A and 210B) and the conductor wire group 10 on the other side (the conductor wire group 10 held by the gripping devices 210C and 210D) that are folded back at the folding line 220.

[0038] The leading edge 230a of the guide jig 230 is positioned so as to be parallel to the folding line 220. By positioning the guide jig 230, when the conductor wire group 10 is folded back along the folding line 220, the starting point of the folding back of the leg portion 12 of each conductor wire 1 is supported along the leading edge 230a. This stabilizes the position of the fulcrum P (see FIGS. 12 and 14) during rotation in the folding back process. The fulcrum P corresponds to the apex 102b of the coil end portion 102 of the conductor 100. Since the apex 102b of the coil end portion 102, which is folded into a substantially U-shape in a later process, can be made smaller in diameter, the apex 102b can be formed with a small thickness. Note that the leading edge 230a of the guide jig 230 is slightly offset by a distance D toward the gripping device 210C with respect to the folding line 220 to ensure smooth folding back of each leg portion 12.

[0039] 13, the conductor wire group 10 is folded back along the folding line 220. Therefore, the conductor wire group 10 on one side to be folded back and the conductor wire group 10 on the other side are bent in a direction in which the leg portions 12 of the same conductor wires 1 overlap each other, with the guide jig 230 sandwiched between them (primary folding back process).

[0040] As shown in FIG. 14, the primary folding process ends when the leg portions 12 of the conductors 1 constituting the folded-back conductor wire group 10 approach the upper surface 230b of the guide jig 230. Specifically, the gripping devices 210A and 210B rotate 150° from the state shown in FIG. 6 around the folding line 220 as an axis to fold back the conductor wire group 10. After the primary folding process ends, the guide jig 230 retreats from between the folded-back conductor wire group 10. The guide jig 230 is not shown in FIG. 12. Furthermore, the four gripping devices 210A, 210B, 210C, and 210D are not shown in FIG. 13 and subsequent figures.

[0041] After the primary folding process is completed, the gripping devices 210A, 210B move parallel to the X1 direction as shown in Fig. 14 while maintaining the rotation angle at the end of the primary folding process. The X1 direction is a direction along the width direction of the conductors 1 constituting the conductor wire group 10. The X1 direction is parallel to the folding line 220.

[0042] By the parallel movement of the gripping devices 210A and 210B, the legs 12 of the conductor wires 1 constituting the conductor wire group 10 in the coil end portion forming region 10B are inclined so that the inclination directions intersect in a mountain shape, with the fulcrum P at the time of folding as the boundary. This starts the inclination process.

[0043] As the inclined process begins, the leg portions 12 of each conductor wire 1 form a coil end portion 102 having two inclined portions 102a, 102a that intersect obliquely with the vertex 102b at the folding fulcrum P (primary inclined process).

[0044] In the primary slanting step, the leg portion 12 is slanted using the side edge E2 of the gripping device 210B and the side edge E1 of the gripping device 210C, which are arranged on either side of the coil end portion forming region 10B, as fulcrums. These fulcrums correspond to the boundary portion 103 between the coil end portion 102 and the straight portion 101. However, in the coil end portion 102 formed by the primary slanting step, the intersecting angle between the two slanted portions 102a, 102a with the vertex 102b as the boundary is still smaller than that of the coil end portion 102 of the finished conductor 100 shown in FIG.

[0045] After the primary oblique feeding step is completed, as shown in Fig. 16, the gripping devices 210A and 210B further rotate in the R1 direction around the folding line 220 as an axis so as to overlap with the gripping devices 210C and 210D. The gripping devices 210A and 210B rotate 180° around the folding line 220 as an axis from the state shown in Fig. 6, folding back the conductor wire group 10. This completely folds back the conductor wire group 10 (secondary folding back step).

[0046] When the second folding process is completed, the folding process for the first coil end portion forming region 10B of the conductor wire group 10 is completed.

[0047] After the folding process is completed, the gripping devices 210A, 210B, while maintaining the rotation angle at the end of the secondary folding process, move parallel to the X1 direction, the same as in the primary oblique moving process, as shown in Fig. 17. The parallel movement of the gripping devices 210A, 210B forms coil end portions 102 in the same shape as the coil end portions 102 of the finished conductor 100 shown in Fig. 1 in the conductor wires 1 that make up the conductor wire group 10 (secondary oblique moving process).

[0048] When the second oblique running step is completed, the oblique running step for the first coil end portion forming region 10B of the conductor wire group 10 is completed.

[0049] After the start of the folding back process for the first coil end portion forming region 10B of the conductor wire group 10, the primary folding back process, the primary oblique folding process, the secondary folding back process, and the secondary oblique folding process are sequentially performed as described above, and then the gripping devices 210A, 210B, 210C, and 210D each release the gripping of the leg portion 12 of the conductor wire 1. Furthermore, the gripping devices 210A and 210B return to the initial positions shown in FIG.

[0050] Thereafter, the conductor wire group 10 is conveyed a predetermined distance in the Y1 direction as shown in Fig. 18 by driving a conveying mechanism (not shown) of the conductor shaping device 200. The Y1 direction is a direction along the length of the conductors 1 constituting the conductor wire group 10. The Y1 direction is perpendicular to the folding line 220. As a result, the conductor wire group 10 is conveyed to a position where the 12 leg portions 12 in the straight portion forming region 10A that were held by the holding devices 210C and 210D in the previous step can be held by the holding devices 210A and 210B that have returned to their initial positions (conveying step).

[0051] After the conveying process, as shown in Figures 19 to 22, the coil end portion forming region 10B between the holding device 210B and the holding device 210C that have newly held the conductor wire group 10 is subjected to the first folding process, the first oblique moving process, the second folding process, and the second oblique moving process in sequence, as described above.

[0052] The coil end portions 102 thus formed are neatly arranged in the longitudinal direction of the conductor 100, as shown in Fig. 23. The coil end portions 102 are formed by starting the folding process on the conductor wire 10 and then bending the conductor wire 10 obliquely, so that the conductor wire 10 at the vertices 102b is bent into a substantially U-shape in the thickness direction of the conductor 100. Therefore, compared to the conventional case in which the conductor wire 10 is folded back after being folded obliquely, the width W of the vertices 102b of the coil end portions 102 shown in Fig. 24 is less likely to increase. Because the distance between adjacent vertices 102b can be made smaller, the conductor 100 can be wound with a smaller diameter than in the past, enabling the construction of a stator 3 with a smaller diameter.

[0053] The conductor wires 1 constituting the conductor wire group 10 are formed obliquely in the oblique direction after the folding process begins and before they are completely overlapped, thereby suppressing twisting of the vertices 102b of the coil end portions 102. As a result, the expansion of the width W of the vertices 102b is effectively suppressed.

[0054] The conductor 100 is formed by folding back the conductor wire group 10, and therefore has a two-layer structure in which two straight portions 101, 101 are stacked in the thickness direction of the conductor 100. When the conductor 100 is wound around the stator core 31 multiple times, a layer change portion Ta is formed at which the layer (turn) changes in the radial direction of the stator core 31 for each turn of the stator core 31. In this case, to avoid interference between layers at the layer change portion Ta in the conductor 100, it is preferable to fold back the coil end portion forming region 10B of the conductor wire group 10 corresponding to the layer change portion Ta of the conductor 100 in the opposite direction (R2 direction) to the folding back direction (R1 direction) of the previous coil end portion forming region 10B, as shown in FIGS.

[0055] More specifically, as shown in Fig. 25, the coil end portion forming region 10B of the conductor wire group 10 corresponding to the layer change portion Ta of the conductor 100 is transported to a position where it can be folded back, and then the gripping devices 210A, 210B are rotated in the R2 direction as shown in Fig. 26, thereby folding back the coil end portion forming region 10B in the opposite direction to the previous process. This rotation in the R2 direction folds back the coil end portion forming region 10B of the conductor wire group 10 corresponding to the layer change portion Ta of the conductor 100. As a result, as shown in Fig. 27, at each layer change portion Ta, the offset direction in the thickness direction of the conductor 100 to be attached to the stator core 31 is reversed.

[0056] FIG. 27 is a schematic plan view of a conductor 100 wound four times around the stator core 31. The conductor 100 has two straight portions 101, 101 laminated in the thickness direction, resulting in an eight-turn configuration (1T to 8T) and four layer transition portions Ta. At each layer transition portion Ta, the offset direction of the conductor 100 is reversed, so no steps are formed at the layer transition portions Ta when the conductor 100 is wound around the stator core 31. This allows the conductor 100 to be wound with an even smaller diameter. [Explanation of symbols]

[0057] 1 Conductor wire 100 conductors 101 Straight section 102 Coil end 102b Vertex 103 Boundary 230 Guide jig

Claims

1. A conductor forming method for forming a conductor having a mountain-shaped coil end portion and straight portions connected to both ends of the coil end portion by folding back a conductor wire, comprising: a primary folding process in which the conductor wire is folded back using a portion of the conductor wire corresponding to the apex of the coil end portion as a fulcrum, and the folding back process is terminated before one side of the conductor wire to be folded back completely overlaps the other side of the conductor wire to be folded back; a primary oblique movement step, after completion of the primary folding step, of moving the conductor wire on one side to be folded back relative to the conductor wire on the other side to be folded back in a direction intersecting with the extending direction of the straight portion, using a portion of the conductor corresponding to a boundary between the coil end portion and the straight portion as a fulcrum, so as to obliquely move the conductor wire with respect to the vertex; a secondary folding process in which, after the primary oblique folding process is completed, the conductor wire on one side to be folded back is further folded back so as to overlap the conductor wire on the other side to be folded back; and a secondary oblique step of, after completion of the secondary folding step, further moving the conductor wire on one side to be folded back relative to the conductor wire on the other side to be folded back in the same direction as the primary oblique step, thereby forming the coil end portion.

2. 2. The conductor forming method according to claim 1, wherein the first folding process, the first oblique process, the second folding process, and the second oblique process are sequentially repeated multiple times for a plurality of the conductor wires arranged in parallel at regular intervals, thereby forming the coil end portions at both end sides in the extension direction of the straight portion, and forming the band-shaped conductor.

3. 3. The conductor shaping method according to claim 2, wherein the plurality of primary folding steps and secondary folding steps include at least one step of folding the plurality of conductor wires in a direction opposite to the folding direction of the previous primary folding step and secondary folding step.

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