Coil manufacturing method

Abstract

To provide a method for manufacturing a coil that is suitable to be used for a motor and that can improve productivity.SOLUTION: A method for manufacturing a coil has the steps of: winding a round wire conductor M0 to form a round wire coil 11; and pressing the round wire coil 11 by a molding die 51 to form a flat wire coil 12 having one round in a substantially rectangular shape.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a coil.

Background Art

[0002] Conventionally, concentrated-wound rectangular wire coils have been used as components for motors. Also, as a method for manufacturing a coil suitable for use in motors, a method of pressure-welding ends of a plurality of coil pieces to each other is known. This rectangular wire coil can improve the space factor when attached to a stator, enabling higher output and higher performance of motors.

Prior Art Literature

Patent Literature

[0003]

Patent Literature 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] However, for example, in the case of a coil used in a small and lightweight motor, the size of the coil is also reduced, so the method of holding a coil piece with a chuck and performing pressure welding as described in Patent Literature 1 has a problem of deteriorating handleability.

[0005] Furthermore, particularly in the case of a coil for a motor, when assembling (attaching) the coil to a motor (stator), connection between coils and connection between the coil and external connection members (such as terminals and bus bars) are essential. Conventionally, these connections have been performed by, for example, welding or screwing, but when the size of the coil is small, these connection operations become difficult.

[0006] Furthermore, for example, motors used in electric vehicles require high output and high performance, but depending on the application of the motor, there are cases where improvement in productivity (mass production speed) is desired rather than high output and high performance.

[0007] In view of these problems, the present invention aims to provide a method for manufacturing coils that are suitable for use in motors and that can improve productivity. [Means for solving the problem]

[0008] The present invention A method for manufacturing a coil using a molding die having a first mold and a second mold that are relatively movable, wherein the molding die has a substantially rectangular frame shape in a plan view, with a molding region partitioned by the first mold and the second mold having short sides, corners, and long sides, and the width of the corners is set to be larger than the width of the short sides and the width of the long sides. The steps include winding a round wire conductor to form a round wire coil, While housing the round wire coil in the molding region The process includes the step of pressing with the aforementioned molding die to form a flat wire coil with a substantially rectangular shape around its circumference, The amount of pressure applied by the molding die is such that the metal material of the conductor spreads sufficiently to at least the corners. This invention relates to a method for manufacturing a coil, characterized by the following: [Effects of the Invention]

[0009] The present invention aims to provide a method for manufacturing coils suitable for use in motors, which enables improved productivity. [Brief explanation of the drawing]

[0010] [Figure 1] This is a flowchart showing an example of a coil manufacturing method according to this embodiment. [Figure 2] This is a schematic diagram illustrating the coil according to this embodiment, and shows (A) an external view of the conductor material, (B) a front (plan) view of the coil, (C) a cross-sectional view of the coil, and (D) a cross-sectional view of the coil. [Figure 3] This is a schematic diagram showing an example of a coil manufacturing method according to this embodiment, (A) a cross-sectional view, (B) a plan view, (C) a cross-sectional view, and (D) a plan view. [Figure 4] This is a schematic diagram showing an example of a coil manufacturing method according to this embodiment, and (A) is a cross-sectional view, (B) is a plan view, (C) is a cross-sectional view, (D) is a plan view, and (E) is an external perspective view. [Figure 5] This is a schematic diagram showing an example of a coil manufacturing method according to this embodiment, and (A) is a cross-sectional view, (B) is a cross-sectional view, (C) is a cross-sectional view, and (D) is a plan view. [Figure 6] This is a schematic diagram showing an example of a coil manufacturing method according to this embodiment, where (A) is a cross-sectional view, (B) is a cross-sectional view, and (C) is a cross-sectional view. [Figure 7] It is a schematic diagram illustrating an example of a method for manufacturing a coil according to the present embodiment, wherein (A) is a cross-sectional view, (B) is a cross-sectional view, and (C) is a cross-sectional view. [Figure 8] It is a schematic diagram illustrating an example of a coil unit according to the present embodiment, wherein (A) is a top view and (B) is a front view. [Figure 9] It is a flow diagram illustrating an example of a method for manufacturing a coil unit according to the present embodiment. [Figure 10] It is a schematic diagram illustrating an example of a method for manufacturing a coil unit according to the present embodiment, wherein (A) is a plan view and (B) is a top view. [Figure 11] It is a schematic diagram illustrating an example of a method for manufacturing a coil unit according to the present embodiment, wherein (A) is a plan view and (B) is a plan view. [Figure 12] It is a schematic diagram illustrating an example of a method for manufacturing a coil unit according to the present embodiment. [Figure 13] It is a schematic diagram illustrating an example of a method for manufacturing a coil unit according to the present embodiment. [Figure 14] It is a schematic diagram illustrating an example of a method for manufacturing a coil unit according to the present embodiment, wherein (A) is a top view, (B) is a plan view, and (C) is a plan view. [Figure 15] It is a schematic diagram illustrating an application example of the coil unit according to the present embodiment, wherein (A) is a front view and (B) is a perspective view. [Figure 16] It is a cross-sectional view illustrating an example of the coil or the coil unit according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present drawing and each of the subsequent drawings, a part of the configuration is appropriately omitted to simplify the drawings. In the present drawing and each of the subsequent drawings, the sizes, shapes, thicknesses, and the like of members are exaggerated as appropriate.

[0012] <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a flow chart showing an example of a coil manufacturing method according to the first embodiment of the present invention. FIGS. 2 to 7 are schematic diagrams for explaining an example of the coil manufacturing method of the first embodiment.

[0013] First, referring to FIG. 1, the coil manufacturing method of the present embodiment includes a round wire coil forming step (step S01), a rectangular wire coil forming step (step S03), an annealing step (step S05), and a coating step (step S07).

[0014] [Round Wire Coil Forming Step (Step S01)] FIG. 2 is a diagram for explaining the round wire coil 11 of the present embodiment, in which FIG. 2(A) is an external view of a conductor (metal wire rod) as a material, FIG. 2(B) is a front view of the round wire coil viewed from the virtual axis AX direction, FIG. 2(C) is a cross-sectional view taken along line X-X of FIG. 2(B), and FIG. 2(D) is a cross-sectional view taken along line Y-Y of FIG. 2(B).

[0015] As shown in FIG. 2(A), the material of the coil is, for example, a long conductor M0, more specifically, a metal wire (round wire conductor) M0 having a substantially circular cross-sectional shape orthogonal to the longitudinal (long) direction. As an example, the round wire conductor M0 is a metal wire mainly made of aluminum. A metal wire mainly made of aluminum refers to a metal wire made of aluminum or an aluminum alloy, and is, for example, a linear metal material containing 50% or more of aluminum or an aluminum alloy.

[0016] As shown in FIGS. 2(B) to 2(D), first, the round wire conductor M0 is spirally wound to form the round wire coil 11. The round wire coil 11 is a helical structure formed by winding the round wire conductor M0 around a certain virtual axis AX, and connecting one winding region (hereinafter referred to as "one-turn region CR") so as to overlap in the extending direction of the virtual axis AX, and is a so-called concentrated winding coil. The virtual axis AX is the axis of the spiral (coil), and is hereinafter referred to as the spiral axis AX. A region where a plurality of one-turn regions CR overlap to form a helical structure is referred to as a winding region of the coil.

[0017] The round wire coil 11 is a coil that has not undergone any special (intentional) shaping other than winding a round wire conductor M0, such as forming right-angle corners. For example, the shape in plan view shown in Figure (B) is wound in such a way that it is approximately rectangular with curved corners (rounded corners). In other words, in this example, the round wire coil 11 is shaped such that one turn of the winding (helix) region (one turn region CR) consists of a short side SS, a long side LS, and a curved corner (curved corner) RR. Note that although this round wire coil 11 is illustrated as a coil wound in an approximately rectangular shape with rounded corners in plan view (Figure (B)), it is not limited to this, and the round wire coil 11 can be any coil made by winding a round wire conductor M0. In other words, the shape in plan view of the round wire coil 11 may be an oval shape or an ellipse shape without a curved corner RR. For example, when manufacturing a coil to be attached to a stator as a motor component, it is preferable that the round wire coil 11 be wound in a shape that is elongated in one direction when viewed from above. In this example, as shown in Figures (B) to (D), the round wire coil 11 is formed such that a short side SS, a long side LS, and a curved corner RR exist as a single turn region CR. Also, as an example, both ends of the round wire coil 11 are located outside the helical turn region (the part where the single turn region CR overlaps) as lead-out portions TO.

[0018] [Formation process of flat wire coil (Step S03)] Next, the round wire coil 11 is pressed by the molding die 51 to form the rectangular wire coil 12. Figures 3 and 4 are schematic diagrams of the process of manufacturing a coil (rectangular wire coil 12) whose outer shape after pressing is approximately a rectangular parallelepiped using the molding die 51. Figures 3(A), 3(C), 4(A), and 4(C) are cross-sectional views corresponding to the cross-section of line XX in Figure 2(B), and Figures 3(B), 3(D), 4(B), and 4(D) are plan views showing the molding region 550 of the round wire coil 11 by the molding die 51.

[0019] As shown in Figure 3(A), the molding die 51 has a first die 511 and a second die 512 that can move relative to one direction (for example, vertically).

[0020] In this example, the first mold 511 is the upper mold, and the second mold 512 is the lower mold. The first mold (upper mold) 511 has a base portion 510 and a recess 513 provided in the base portion 510 that can accommodate a part of the round wire coil 11 before molding (pressing). In other words, in this example, the first mold 511 is a concave mold. In this case, the overall shape of the recess 513 is approximately a rectangular parallelepiped, and it has an insertion hole 513B near its center. The surface around the insertion hole 513B that faces the opening OP of the recess 513 (the bottom surface of the recess, the upper surface in the figure) becomes the pressing surface 513A of the round wire coil 11.

[0021] The second mold 512 (for example, the lower mold) has a base portion 514 and a shaft 515 that protrudes from the base portion 514 toward the first mold 511. The shaft 515 is I-shaped in plan view and can be inserted through the inner circumference of the round wire coil 11 to support it. In other words, in this example, the second mold 512 is a convex mold. The height H1 of the shaft 515 is greater than the height H2 of the round wire coil 11 (thickness along the extending direction of the helical axis AX).

[0022] Furthermore, as shown in Figure 3(C), the length (width) W1 of the recess 513 in the shorter direction is slightly larger than the length (width) W2 of the shorter side SS of the round wire coil 11. Also, as shown in Figure 3(D), the length L1 of the recess 513 in the longer direction is slightly larger than the length L2 of the longer side LS of the round wire coil 11.

[0023] Referring to Figure 3(B), the molding region 550 in this embodiment is demarcated by the relative movement (proximity) of the first mold 511 and the second mold 512, that is, by combining a concave mold and a convex mold. The molding mold 51 houses the round wire coil 11 in the molding region 550 and presses and deforms it. In this example, the first mold 511 is substantially rectangular in shape, and the second mold 512 is I-shaped so that it can be housed inside it, so the shape of the molding region 550 is a rectangular frame shape with a short side portion 551, a long side portion 552, and a corner portion 553 in plan view. The corner portion 553 is configured to be (approximately) right angle (so as not to form an intentionally curved portion).

[0024] When the length of the molding region 550 in the direction that crosses its circumferential direction (the length in the short direction of the band when the circumferential direction is the longitudinal direction of the band) is defined as the "width of the molding region 550", the width WL3 (diagonal length) of the corner portion 553 is set to be larger than the width WL2 of the long side portion 552. Furthermore, the width WL1 of the short side portion 551 is set to be larger than the width WL2 of the long side portion 552.

[0025] [Formation process of flat wire coil (Step S03)] The molding process using this molding die 51 will now be described chronologically with reference to Figures 3 and 4. First, as shown in Figure 3(A), the round wire coil 11 is placed in the second mold 512 so that the shaft 515 of the second mold 512 is inserted through the inner circumference of the round wire coil 11. Then, as shown in Figure 3(C), the first mold 511 and the second mold 512 are moved relative to each other in a direction that brings them closer together. As a result, the recess 513 covers the outside of the round wire coil 11. The shaft 515 is also inserted through the insertion hole 513B of the first mold 511. The round wire coil 11 is housed in the molding region 550 created by the first mold 511 (its recess 513) and the second mold 512 (its shaft 515) (Figure 3(D)).

[0026] As shown in Figure 4(A), when the first mold 511 and the second mold 512 are brought even closer together, the round wire coil 11 is housed in the molding region 550 and pressed in the direction of extension of the helical axis AX by the pressing surface 513A and the base portion 514. As a result, the diameter of the round wire conductor M0 is compressed along the direction of extension of the helical axis AX (helical axis direction A1), and the diameter of the round wire conductor M0 is stretched along the plane direction perpendicular to the helical axis AX (helical axis intersecting plane direction A2), so that the cross-sectional shape of the round wire conductor M0 intersecting (orthogonal to) the direction of extension (longitudinal direction, helical direction) (hereinafter simply referred to as "the cross-sectional shape of the conductor") becomes approximately oval (ellipse, or rounded rectangle).

[0027] Next, as shown in Figure 4(C), the first mold 511 and the second mold 512 are brought closer together to further press the round wire coil 11. The length (thickness) of the conductor M0 of the round wire coil 11 is further compressed along the helical axis direction A1, and the length of the conductor (length in the direction perpendicular to the direction of helical progression (width in the short side direction of the band)) is further extended along the direction of the intersecting surface A2 of the helical axis. As shown in Figure 4(D), the inner circumferential corners RI of the one-turn region CR are formed to be approximately right angles in a plan view, and as a result, a flat rectangular wire coil 12 as shown in Figure 4(E) is formed. In this embodiment, the flat rectangular wire coil 12 not only has a roughly rectangular cross-sectional shape of the conductor (see Figure 4(C)), but at least the inner circumferential corners RI of the one-turn region CR (shown by dashed circles in Figures 4(D) and 4(E)) are approximately right angles, so that the one-turn region CR becomes a roughly rectangular coil in a plan view.

[0028] In this embodiment, the object to be pressed is the round wire conductor M0 shown in Figure 2, but the molding region 550 is configured with right-angled corners 553 as shown in Figure 3(B). When the round wire conductor M0 is compressed in the direction of the helical axis A1, the metal material also flows in the direction of the intersecting surface A2 of the helical axis and spreads along the shape of the molding region 550. As shown in Figure 4, the shape of the round wire coil 11 increases in length in the direction perpendicular to the direction of helical progression (width in the short side direction of the band), and the curvature of the curved corner RR increases, forming a flat wire coil 12 in which at least the inner side corner RI of the one-turn region CR is approximately right-angled. The amount of pressure applied by the molding die 51 is set to an amount that allows the metal material to spread sufficiently to at least the corners 553 of the molding region 550.

[0029] In this embodiment, the molding region 550 formed by the molding die 51 has a corner portion 553 width WL3 (diagonal length) set to be larger than the long side portion 552 width WL2, and furthermore, the short side portion 551 width WL1 is set to be larger than the long side portion 552 width WL2. The short side portion 551, including the corner portions 553 at both ends, is a region with a short straight length in the longitudinal direction of the belt, and if local accumulation of the pressed metal material occurs, there is a risk of unintended thickened areas being formed. In this embodiment, by making the width WL3 of the corner portion 553 and the width WL1 of the short side portion 551 larger than the width WL2 of the long side portion, the flowing metal can be more easily dispersed over the entire circumference of the region CR, and the occurrence of thickened areas due to local accumulation of metal can be avoided.

[0030] Furthermore, the molding process using the molding die 51, that is, the molding from the round wire coil 11 to the flat wire coil 12, may be performed with a single press or with multiple presses (stamping).

[0031] As shown in Figure 4(C), the rectangular wire coil 12 not only has a roughly rectangular cross-sectional shape for the conductor, but as shown in Figures 4(D) and 4(E), in a plan view, at least the inner circumference corners RI are roughly right angles, resulting in a roughly rectangular coil.

[0032] [Annealing process (Step S05)] Subsequently, the rectangular wire coil 12 is annealed as needed to deform it into the desired shape. This deformation is, for example, for a later coating process, and the edges of the rectangular wire coil 12 are spaced apart to allow for coating. Alternatively, the lead-out portion TO for connection to a desired terminal may be deformed. The annealing process is optional. Furthermore, if burrs (unintended protruding parts, etc.) are generated on the side of the rectangular wire coil 12, for example, due to molding with a mold, a burr removal process may be performed before or after the annealing process.

[0033] [Coating process (Step S07)] Next, the surface of the conductors of the rectangular wire coil 12 is coated with an insulating resin. The insulating resin coating is performed, for example, by electrodeposition coating. For example, by molding after annealing, each circumference of the spiral of the rectangular wire coil 12 is spaced apart, allowing sufficient contact with the paint liquid throughout the entire spiral structure. As a result, the conductors at each circumference of the spiral are insulated from each other. The insulating resin coating may also be applied by spraying the insulating resin material or by injection molding of the insulating resin.

[0034] Furthermore, after coating with insulating resin, the flat wire coil 12 is appropriately molded (for example, by compressing it to reduce the distance between CR regions for one full turn, or by molding the outer shape of the coil, etc.) to complete the flat wire coil 12.

[0035] As described above, according to this embodiment, a round wire conductor M0 can be wound in a spiral shape and pressed (pressed) in the spiral axis direction A1 by a molding die 51 to easily form a highly accurate rectangular flat wire coil 12 in plan view.

[0036] The flat wire coil 12 is formed by winding a long conductor in a spiral shape, and its outer shape is configured to be approximately a rectangular parallelepiped, with the cross-sectional shape of the conductor being approximately rectangular. Furthermore, in a plan view taken from the axial direction of the spiral, the flat wire coil 12 has at least the inner circumference corners RI formed at approximately right angles, and the region CR for one full turn is approximately rectangular.

[0037] Such a flat wire coil 12 with an inner circumference corner RI that is approximately right-angled can improve the space utilization ratio when mounted on a stator, for example, and contribute to the high performance of the motor. In other words, according to this embodiment, a flat wire coil 12 suitable as a motor component can be manufactured with simple equipment and processes without requiring complex processes or equipment, thereby reducing manufacturing costs and improving productivity (mass production speed).

[0038] Other examples of the molding die 51 will be described with reference to Figures 5 to 7. Figures 5 to 7 are diagrams showing examples of manufacturing a flat wire coil 12 using other molding dies 51, and each of Figures 5 to 7 (A) is a cross-sectional view corresponding to Figure 3(A), each (B) is a cross-sectional view corresponding to Figure 4(A), and each (C) is a cross-sectional view corresponding to Figure 4(C). Also, Figure 5(D) is a plan view of the molding region 550 corresponding to Figure 3(B).

[0039] Figure 5 shows an example in which the outer shape of the manufactured flat wire coil 12 is approximately a rectangular parallelepiped, and the first mold (upper mold) 511 of the molding die 51 is a convex mold, and the second mold (lower mold) 512 is a concave mold. As shown in Figure 5(A), the first mold (upper mold) 511 of the molding die 51 has a base portion 516 and a pressing portion 517 that protrudes from the base portion 516 toward the second mold 512. The pressing portion 517 has an outer shape of a rectangular parallelepiped. The pressing portion 517 also has an I-shaped insertion hole 517B in plan view near its center (see Figure 5(D)), which is a rectangular frame-shaped projection in plan view. The pressing portion 517 has a pressing surface 517A on the side facing the second mold 512.

[0040] The second mold (lower mold) 512 has a roughly rectangular recess 518 provided in the base portion 520 and a shaft 519 protruding from near its center. The shaft 519 is I-shaped in plan view, similar to the shaft 515 shown in Figure 3 (Figure 5(D)). A part of the pressing portion 517 can be accommodated in the recess 518, and the shaft 519 can be inserted through the insertion hole 517B.

[0041] In this case, as shown in Figure 5(A), the round wire coil 11 formed from the round wire conductor M0 is housed in the recess 518 of the second mold 512 and pressed (compressed) in the helical axis direction A1 by the pressing portion 517 of the first mold 511 (Figure 5(B)). In this case, the molding region 550 of the round wire coil 11 is demarcated by the pressing portion 517 of the first mold 511 and the recesses 518 and 513 of the second mold 512, and its shape in plan view is a rectangular frame shape having a short side portion 551, a corner portion 553 and a long side portion 552, as shown in Figure 5(D). In other words, the shape of the molding region 550 is the same as the molding region 550 shown in Figure 3(B). The round wire coil 11 is housed in the molding region 550 and pressed, and a flat wire coil 12 is formed as shown in Figure 5(C). The external shape of the flat wire coil 12 is the same as that shown in Figure 4(E).

[0042] In other words, the flat wire coil 12 in this case is also a coil formed by winding a long conductor in a spiral shape, with an outer shape that is approximately a rectangular parallelepiped, and the cross-sectional shape of the conductor is approximately rectangular. Furthermore, in a plan view taken from the axial direction of the spiral, the flat wire coil 12 is a coil in which at least the inner circumference corners RI are formed at approximately right angles, and the region CR for one full turn is approximately rectangular.

[0043] Figure 6 shows an example of a molding die 51 in which the outer shape of the finished coil (flat wire coil 12) is approximately a truncated square pyramid. In this example, the mold configuration is the same as that shown in Figure 5, except that the outer shape of the finished coil (flat wire coil 12) is a truncated square pyramid. Specifically, as shown in Figure 6(A), the first mold (upper mold) 511 of the molding die 51 has a base portion 516 and a pressing portion 517 that protrudes from the base portion 516. The pressing portion 517 has an outer shape that is a truncated square pyramid, and has an I-shaped insertion hole 517B in the vicinity of its center in a plan view, and is a projection that is a rectangular frame in a plan view. The surface of the tip of the pressing portion 517 that faces the second mold 512 is the pressing surface 517A. The second mold (lower mold) 512 has a recess 518 and an I-shaped shaft 519 in a plan view that protrudes in the vicinity of its center. The shape of the recess 518 is a truncated square pyramid. The recess 518 can accommodate a portion of the pressing portion 517, and the shaft 519 can be inserted through the insertion hole 517B.

[0044] The molding region 550 of the round wire coil 11 is demarcated by the pressing portion 517 of the first mold 511 and the recess 518 of the second mold 512, and its shape in plan view is a rectangular frame shape having a short side portion 551, a corner portion 553 and a long side portion 552, similar to Figure 5(D).

[0045] In this case, as shown in Figure 6(A), the round wire coil 11 formed from the round wire conductor M0 is housed in the recess 518 of the second mold 512 and pressed (compressed) in the helical axis direction A1 by the pressing portion 517 (pressing surface 517A) of the first mold 511 (Figure 6(B)). As a result, the flat wire coil 12 is formed as shown in Figure 6(C).

[0046] The appearance of the flat wire coil 12 in this example is the same as that shown in Figure 4(E), except that its outer shape is approximately a truncated square pyramid. That is, the flat wire coil 12 is a coil formed by winding a long conductor in a spiral shape, with an outer shape approximately a truncated square pyramid, and the cross-sectional shape of the conductor is approximately rectangular. Furthermore, in a plan view taken from the axial direction of the spiral, the flat wire coil 12 is a coil in which at least the inner circumferential corners RI are formed at approximately right angles, and the region CR for one full turn is approximately rectangular.

[0047] Figure 7 shows another example of a molding die 51 in which the outer shape of the completed coil (flat wire coil 12) is approximately a truncated square pyramid. In this example, the mold configuration is the same as that shown in Figures 3 and 4, except that the outer shape of the completed coil (flat wire coil 12) is a truncated square pyramid. Specifically, the first mold (upper mold) 511 of the molding die 51 has a base portion 510, a recess 513 provided in the base portion 510 that can accommodate a part of the round wire coil 11 before molding (pressing), and an I-shaped through hole 513B in the vicinity of its center in a plan view. The second mold 512 (for example, the lower mold) has a base portion 514 and an I-shaped shaft 515 in a plan view that protrudes from the base portion 514 toward the first mold 511. In the molding die 51, the molding region 550 partitioned by the first mold 511 (its recess 513) and the second mold 512 (its shaft 515) has a rectangular frame shape similar to that of Figure 3(D).

[0048] In this case, as shown in Figure 7(A), the round wire coil 11 formed from the round wire conductor M0 is housed in the recess 513 of the first mold 511 and pressed (compressed) in the helical axis direction A1 by the pressing surface 513A of the recess 513 and the base portion 514 (Figure 7(B)). As a result, the flat wire coil 12 is formed as shown in Figure 7(C).

[0049] The appearance of the flat wire coil 12 in this example is the same as that shown in Figure 4(E), except that its outer shape is approximately a truncated square pyramid. That is, the flat wire coil 12 is a coil formed by winding a long conductor in a spiral shape, with an outer shape approximately a truncated square pyramid, and the cross-sectional shape of the conductor is approximately rectangular. Furthermore, in a plan view taken from the axial direction of the spiral, the flat wire coil 12 is a coil in which at least the inner circumferential corners RI are formed at approximately right angles, and the region CR for one full turn is approximately rectangular.

[0050] Here, for example, the molding die 51 shown in Figure 5 is configured such that as pressing progresses, the outer side of the upper die 511 fits into the inner side of the lower die 512. As shown in Figures 5(B) and 5(C), during pressing, the sides B1 and B2 of both dies come into close proximity and face each other, forming a minute gap, and the sides B1 and B2 move relative to each other. In such a configuration, depending on the pressing conditions and the material of the conductor (especially if it is a material that is easily deformed), a part of the conductor that deforms fluidly due to the pressing may get stuck in this gap, which may cause unintended thickened portions or protruding portions that extend towards the upper die, like burrs, to form on the outer circumference of the coil. In this case, it is desirable to remove the thickened portions or burr-like protrusions after molding (before the coating process) of the second-shaped flat wire coil 12 and / or the flat wire coil 12, if necessary.

[0051] In contrast, in the case of the mold configurations shown in Figures 3, 4, and 7, there are no sides that move in close proximity and face each other in the first mold 511 and the second mold 512 (configurations corresponding to sides B1 and B2 in Figure 5). In other words, at least in the side portions of the object to be molded (round wire coil 11, flat wire coil 12), no gap is created between the first mold 511 and the second mold 512 into which the conductor can enter. Therefore, it is possible to prevent the formation of unintended thickened portions or burr-like protrusions on the outer circumference of the coil.

[0052] In this embodiment, the round wire conductor M0 is exemplified as a metal wire mainly composed of aluminum, but it is not limited to this, and may be a metal wire mainly composed of copper, or a metal wire mainly composed of other metals. A metal wire "mainly composed of (a certain) metal" refers to a metal wire composed of that metal or an alloy of that metal, for example, a linear metal material containing 50% or more of that metal or an alloy of that metal.

[0053] Furthermore, the round wire conductor M0 may be a composite material of multiple different metals. For example, in the longitudinal direction of the round wire conductor M0, a first metal (e.g., copper) and a different second metal (e.g., aluminum) may be connected. In this case, the round wire conductor M0 switches to different types of metal materials in the longitudinal direction. In other words, the round wire coil 11 wound with the round wire conductor M0 and the flat wire coil 12 formed therefrom become coils in which the metal materials switch to different types in the direction of spiral progression (partway through the rotation). This makes it possible, for example, to manufacture a flat wire coil 12 in which, when the flat wire coil 12 is attached to a stator, the turns of the spiral closer to the rotor (one or more one-turn regions CR) are made of aluminum and the other turns are made of copper.

[0054] Furthermore, in this case, it is preferable to join the multiple metal materials by pressing their respective end faces together in the longitudinal direction (for example, by cold pressure welding).

[0055] In the above embodiment, the round wire coil 11 was shown as being wound so that its outer shape is approximately a rectangular trapezoid; however, the round wire coil 11 may also be wound so that its outer shape is a truncated square pyramidal shape.

[0056] <Second Embodiment> A second embodiment of the present invention will be described with reference to Figures 8 to 14. The second embodiment relates to a method for manufacturing a coil unit 100 in which a plurality of coils C2 are connected, and the coil manufacturing method of the first embodiment can be applied.

[0057] Figure 8 is an external view showing an example of a coil unit 100 of the second embodiment, where Figure (A) is a top view and Figure (B) is a front view of a coil C2 (C21) constituting the coil unit 100, viewed from the direction of the helical axis AX.

[0058] As shown in the figure, the coil unit 100 of the second embodiment is composed of multiple (in this case, three) coils C2 connected by a connecting portion 300. Each of the three coils C2 (C21 to C23) is, for example, a concentrated winding coil with a helical structure, and in a front view viewed from the direction of the helical axis AX, the region CR for one turn is a roughly rectangular flat wire coil. The coil unit 100 is arranged so that the long sides LS of each coil C2 are adjacent (close to each other), and the coils are connected by the connecting portion 300 (300A, 300B) at a position that does not overlap with the circumferential region of each coil C2 (in this example, above the helix (circumferential region) of each coil C2). Specifically, one end T1 of the first coil (coil C21 located on the left in Figure 8) of its winding becomes an outlet portion TO (TO1), and the other end T2 is connected to one end T3 of the second coil (coil C22 located in the middle in Figure 8) by a connecting portion 300A. The other end T4 of the second coil C22 is connected to one end T5 of the third coil (the coil located on the right in Figure 8) C23 by another connecting part 300B, and the other end T6 of the third coil C23 becomes another lead-out part TO (TO2).

[0059] The coil unit 100 consists of three coils C2 that are integrally covered with insulating resin. When the spirals of each coil C2 are unfolded, the coil unit 100 becomes a single conductor, and the insulating resin covers the surface of this single conductor. In other words, in the circular region of each coil C2, each one-turn region CR is insulated from the other one-turn regions CR by the insulating resin.

[0060] Figure 9 is a flowchart showing an example of the manufacturing process for the coil unit 100 of the second embodiment. The manufacturing process for the coil unit 100 includes the steps of: winding a conductor to form a first-shaped coil unit 101 consisting of a connecting portion 300 and a plurality of first-shaped coils C1 connected by the connecting portion 300 (step S11); pressing the first-shaped coil unit 101 with a molding die to form a second-shaped coil unit 102 consisting of a plurality of second-shaped coils C2 connected together (step S13); deforming the connecting portion 300 (step S15); annealing the second-shaped coil unit 102 (step S17); and covering the second-shaped coils 102 with a resin material (step S19).

[0061] Here, in the second embodiment, the first coil shape C1 and the second coil shape C2 are both coils formed by winding a conductor, and are coils in which the cross-sectional shape and / or size (cross-sectional area) of the conductor intersects (is perpendicular to) the direction in which the winding progresses (the direction of extension of the conductor, the longitudinal direction).

[0062] Specifically, the first coil shape C1 is, for example, a coil formed by spirally winding a long conductor (round wire conductor M0) with a roughly circular cross-sectional shape, and its outer shape is roughly rectangular (or roughly truncated square). That is, as an example, the first coil shape C1 is the round wire coil 11 shown in Figure 2. The conductor (round wire conductor M0) in the second embodiment is the same as that described in the first embodiment.

[0063] The second-type coil C2, for example, has a structure in which a long conductor is wound in a spiral, the cross-sectional shape of the conductor is not circular, and the outer shape of the coil is configured to be approximately a truncated square pyramid (or a rectangular parallelepiped). As an example, the cross-sectional shape of the conductor of the second-type coil C2 is approximately rectangular. Furthermore, the second-type coil is a coil in which, in a plan view from the axial direction of the spiral, at least the inner circumference corners RI are formed at approximately right angles, and the region CR for one full turn is approximately rectangular. That is, as an example, the second-type coil is a flat rectangular wire coil 12 as shown in Figures 4(E) and 7.

[0064] In the following description, we will explain, as an example, the case where the first coil shape C1 is a round wire coil 11 (see Figure 2), and the second coil shape C2 is a rectangular wire coil 12 with an outer shape that is roughly frustoconical (Figures 7 and 8). Furthermore, we will mainly describe the parts that differ from the first embodiment, and will omit explanations of matters that are not specifically mentioned, assuming they are the same as in the first embodiment.

[0065] In other words, the coil unit 100 shown in Figure 8 is, in its completed state, formed by connecting multiple (three in this example) flat wire coils 12 of the first embodiment via connecting parts 300, and is formed from a single round wire conductor M0 as shown in Figure 2. Below, an example of a manufacturing method for the coil unit according to the second embodiment of the present invention will be described.

[0066] [Formation process of the first-shape coil (round wire coil) unit (Step S11)] First, a round wire conductor M0 is wound to form a first-shaped coil unit (round wire coil unit) 101 consisting of a connecting portion 300 and a plurality of round wire coils 11 connected by the connecting portion 300.

[0067] Figure 10 is an external view of the round wire coil unit 101, where Figure (A) is a view from the direction of the helical axis AX (plan view), and Figure (B) is a schematic view of Figure (A) from above (top view).

[0068] In this example, the round wire coil unit 101 consists of three round wire coils 11A to 11C connected by a connecting part 300. Hereafter, when it is necessary to distinguish between the three round wire coils 11A to 11C, for the sake of explanation, they will be referred to as the first round wire coil 11A, the second round wire coil 11B, and the third round wire coil 11C.

[0069] The material (wire) of the round wire coil unit 101 is the same round wire conductor M0 as in the first embodiment (Figure 2(A)). More specifically, the round wire conductor M0 is wound with a desired number of turns to form the first round wire coil 11A. The end T1 of the first round wire coil 11A becomes the lead-out portion TO1. The other end T2 of the first round wire coil 11A is secured to a predetermined length in an unwound state, and the second round wire coil 11B is wound continuously around it. The end T3 of the second round wire coil 11B and the end T2 of the first round wire coil 11A are continuous, and the unwound round wire conductor M0 between ends T2 and T3 becomes the connecting portion 300 (300A). Similarly, the other end T4 of the second round wire coil 11B is secured to a predetermined length in an unwound state, and the third round wire coil 11C is wound continuously around it. The end T5 of the third round wire coil 11C and the end T4 of the second round wire coil 11B are continuous, and the unwound round wire conductor M0 between ends T4 and T5 forms a connecting section 300. The other end T6 of the third round wire coil 11C becomes another lead-out section TO2.

[0070] In this example, the initial (before pressing by the mold) planar arrangement of the three round wire coils 11A to 11C is shown in Figure 10(A) as a triangular shape (approximately Y-shape), with each coil connected by a connecting portion 300. However, the initial arrangement is not limited to this example, as long as each round wire coil 11 is connected by a connecting portion 300 of a predetermined length. For example, the three round wire coils 11A to 11C may be connected to each other via the connecting portion 300 and arranged side by side so that their long sides LS are parallel.

[0071] In this example, as shown in Figure 10(B), when the helical axis AX is viewed from the R direction, the three round wire coils 11A, 11B, and 11C have the same winding direction (winding direction), for example, all are wound counterclockwise (left-handed). The three round wire coils 11A, 11B, and 11C may also be wound clockwise (right-handed).

[0072] In this way, a round wire coil unit 101 is formed, consisting of a connecting portion 300 and a plurality (in this case, three) of round wire coils 11A to 11C connected by the connecting portion 300. Both the lead-out portions TO1 and TO2 and the connecting portion 300 are located outside the helical region of the round wire coils 11A to 11C.

[0073] [Formation process of the second-shaped coil unit (flat wire coil unit) (Step S13)] Next, the round wire coil unit 101 is pressed by the molding die 61 to form a second shaped coil unit (flat wire coil unit) 102. Figure 11 is a schematic diagram showing an example of the molding die 61, where Figure (A) is a plan view of the first die 611 and Figure (B) is a plan view of the second die 612. The molding die 61 has a first die 611 and a second die 612 that can move relative to one direction (for example, vertically), and a part of the round wire coil unit 101 is pressed by the proximity of the first die 611 and the second die 612.

[0074] As an example, the molding die 61 is similar in configuration to the first embodiment, except that the number of round wire coils 11 that can be pressed by a pair of first molds 611 and second molds 612 is multiple (in this case, 3), meaning that the round wire coil unit 101 can be pressed integrally. In other words, the first mold (for example, the upper mold) 611 has three recesses 613 formed in a single base portion 610. The three recesses 613 have the same configuration (shape), and are all the same as the recesses 513 shown in Figures 3, 4, or 7 of the first embodiment, including their cross-sectional views. In other words, the recess 613 has an insertion hole 613B near the center, and the bottom surface of the recess 613 around it becomes the pressing surface 613A. The second mold 612 (for example, the lower mold) has a base portion 614 and a shaft 615 that protrudes from the base portion 614 toward the first mold 611. The three shafts 615 have the same configuration (shape), and are all the same as the shaft 515 shown in Figure 3, 4, or 7 of the first embodiment, including in cross-sectional view. Here, as an example, the outer shape of the second coil C2 (flat wire coil 12) is approximately a truncated square pyramidal shape, as shown in Figure 8, and the configuration of the molding die 61 is the same as in Figure 7. Note that the molding die 61 may also have a configuration as shown in Figure 5 or 6 of the first embodiment.

[0075] The molding process using the molding die 61 will be described chronologically below. The cross-sectional shapes of each round wire coil 11A to 11C during pressing are the same as in the first embodiment, so please refer to Figures 3, 4, and 7. As shown in Figure 11(B), first, the round wire coils 11A to 11C are inserted through each of the three shafts 615 of the second mold 612. Then, the first mold 611 and the second mold 612 are moved relative to each other in a direction that brings them closer together (see Figure 7(A)). The three recesses 613 of the first mold 611 cover the outside of the corresponding round wire coils 11A to 11C. The shafts 615 of the second mold 612 are inserted through the insertion parts 613B provided in the first mold 611 (see Figure 3(C)). When the first mold 611 and the second mold 612 are brought even closer together, the round wire coils 11A to 11C are each housed in a molding region (similar to the molding region 550 shown in Figure 3) demarcated by the pressing surface 613A of the first mold 611 and the base portion 614 and shaft 615 of the second mold 612, and are pressed in the direction of the helical axis A1 by the pressing surface 613A and the base portion 614 (see Figure 7(B)).

[0076] As a result, in the round wire coils 11A to 11C, the diameter of the round wire conductor M0 is compressed along the helical axis direction A1, and the diameter of the round wire conductor M0 is stretched along the direction A2 where the helical axis intersects, forming the rectangular wire coils 12A to 12C. In this embodiment, the rectangular wire coils 12A to 12C not only have a substantially rectangular cross-sectional shape of the conductor, but at least the inner corner RI of the one-turn region CR is substantially right-angled, so that the one-turn region CR becomes a substantially rectangular coil in plan view (see Figures 7(C) and 4(E)).

[0077] Although detailed illustrations are omitted in Figure 11, as an example, the lead-out section TO and connecting section 300 of the round wire coil unit 101 are configured such that they are not affected by the pressing force (not crushed) by spacers (and / or covers), for example. In other words, only the substantial helical structure portion of the multiple round wire coils 11A to 11C of the round wire coil unit 101 is pressed, and the original shape of the round wire conductor M0 is maintained at the connecting section 300.

[0078] In this way, a flat wire coil unit 102 is formed in which multiple flat wire coils 12A to 12C are connected by connecting portions 300 of round wire conductor M0.

[0079] [Deformation process of the connecting part (Step S15)] Next, the deformation process of the connecting portion 300 will be explained with reference to Figure 12. Figure 12 is a plan view of the flat wire coil unit 102 as seen from the direction of the helical axis AX. The flat wire coil unit 102 consists of three flat wire coils 12A to 12C connected by connecting portions 300 (300A, 300B) of round wire conductor M0. Hereafter, when distinguishing between the three flat wire coils 12A to 12C, for the sake of explanation, they will be referred to as the first flat wire coil 12A, the second flat wire coil 12B, and the third flat wire coil 12C.

[0080] In this process, at least one of the multiple rectangular wire coils 12A to 12C is deformed so that it moves relative to the other coils. Specifically, the connecting portion 300 is deformed so that at least one coil moves to a position adjacent to (close to) the other coils. The deformation of the connecting portion 300 may include, for example, bending deformation and / or twisting deformation, and may also include stretching.

[0081] To explain in more detail, in this example, as shown in Figure 12(A), the connecting portion 300 (300A, 300B) has a predetermined length, and the three flat wire coils 12A to 12C are arranged spaced apart in a roughly Y-shape. In this process, the connecting portion 300 is deformed (for example, bent in a predetermined direction) to move the three spaced flat wire coils 12A to 12C to a position where their long sides LS are adjacent or close to each other (a position where they are side by side). Note that the flat wire coils 12A to 12C are only pressed in the direction of the helical axis AX, and the winding direction (direction of spiral progression) of each coil has not changed from the state shown in Figure 10(B) in this example. Also, Figure 12(A) shows the state after being molded by, for example, the molding die 61 shown in Figure 11, and the three flat wire coils 12A to 12C are arranged in approximately one horizontal plane. More precisely, at least one full circumference region CR of the uppermost or lowermost (outermost or innermost) layer of each of the rectangular wire coils 12A to 12C is located approximately in the same plane.

[0082] Then, for example, as shown in Figure 12(B), the third flat wire coil 12C is rotated around the second flat wire coil 12B while maintaining the direction of extension of the helical axis AX, and the connecting portion 300B is bent so that it is adjacent to the right side of the second flat wire coil 12B (Figure 12(C)). Since the three flat wire coils 12A to 12C are arranged in approximately one horizontal plane, during the deformation shown in Figure 12(B), for example, a part of the third flat wire coil 12C and a part of the first flat wire coil 12A (for example, near the dashed circle) may interfere with each other. In such cases, the third flat wire coil 12C is moved so as to rotate around the second flat wire coil 12B, and at the same time, a twisting deformation is applied so that the third flat wire coil 12C is also moved in the direction of its helical axis AX.

[0083] Then, as shown in Figure (D), the first rectangular wire coil 12A is rotated around the second rectangular wire coil 12B while maintaining the direction of extension of the helical axis AX, and the connecting part 300A is deformed so that it is adjacent to the left side of the second rectangular wire coil 12B (Figure (E)). Note that the order of deformation of the connecting part 300 is not limited to the above example. For example, the position of the first rectangular wire coil 12A may be moved by deforming the connecting part 300A, and then the position of the third rectangular wire coil 12C may be moved by deforming the connecting part 300B.

[0084] This results in a flat wire coil unit 102 in which three flat wire coils 12A to 12C are arranged side by side so that their respective long sides LS are adjacent to each other.

[0085] Figure 13 shows another example of deforming the connecting portion 300 from the state shown in Figure 12(A). As shown in Figure 13, the connecting portion 300A may be deformed (bent) so that the first flat wire coil 12A is adjacent to the right side of the second flat wire coil 12B while maintaining the extension direction of the helical axis AX, and the connecting portion 300B may be deformed (bent) so that the third flat wire coil 12C is adjacent to the left side of the second flat wire coil 12B while maintaining the extension direction of the helical axis AX, thereby forming a flat wire coil unit 102 in which the three flat wire coils 12A to 12C are adjacent to each other side by side, as shown in Figure 13(B).

[0086] Figure 14 is a schematic diagram showing the connected state of the rectangular wire coils 12A to 12C (round wire coils 11A to 11C) and other examples of deformation of the connecting portion 300. Figure 14(A) is a top view of the rectangular wire coil unit 102 corresponding to Figure 10(B), and Figures 14(B) and 14(C) are schematic plan views of the rectangular wire coil unit 102 viewed from the axial direction of the helix.

[0087] In the example shown in Figure 14(A), when the helical axis AX is viewed from the R direction, the three flat wire coils 12A to 12C connected by the connecting portion 300 have different helical winding directions (winding directions), that is, their winding directions are opposite to each other. For example, the first flat wire coil 12A is wound clockwise (right-handed), the second flat wire coil 12B is wound counterclockwise (left-handed), and the third flat wire coil 12C is wound clockwise (right-handed). Note that the winding directions may be reversed for each of them. These are wound in this manner when forming the round wire coil unit 101.

[0088] In this case, for example, as shown by the arrow in Figure 14(B), the connecting part 300A is twisted so as to rotate around the axis of the connecting part 300A (round wire conductor M0), while moving the first flat wire coil 12A to the right of the second flat wire coil 12B. Also, the connecting part 300B is twisted so as to rotate around the axis of the connecting part 300B (round wire conductor M0), while moving the third flat wire coil 12C to the left of the second flat wire coil 12B.

[0089] As a result, as shown in Figure (C), a flat wire coil unit 102 is formed in which three flat wire coils 12A to 12C are arranged side by side so that their respective long sides LS are adjacent.

[0090] Note that the winding method (winding direction) of the three flat wire coils 12A to 12C and / or the modification method of the connecting portion 300 are examples only, and other winding methods and modifications may be used, not limited to those shown.

[0091] Furthermore, the positional relationship of the three rectangular wire coils 12A to 12C after deformation of the connecting section 300 is not limited to the side-by-side arrangement shown in Figures 12(E), 13(B), and 14(C). The distance between the rectangular wire coils 12A to 12C may be greater than shown, and any arrangement can be selected, such as arranging them so that the long side LS of one rectangular wire coil is inclined relative to the long side LS of another rectangular wire coil 12, rather than side-by-side.

[0092] [Annealing process (Step S17)] Next, if necessary, the flat wire coil unit 102 is annealed and deformed into the desired shape. This deformation is, for example, for the subsequent coating process, and in each of the flat wire coils 12A to 12C, the space between each one-turn region CR and / or between the connecting parts 300A and 300B is separated to the extent that resin can adhere (coat) to them. Alternatively, the lead-out parts TO (TO1, TO2) for connection to desired terminals may also be deformed.

[0093] The annealing process may be performed before the bending process of the connecting portion 300 in addition to this process, or it may be performed before the bending process of the connecting portion 300 instead of this process.

[0094] [Coating process (Step S19)] Next, the surface of the conductor of the rectangular wire coil unit 102 is coated with insulating resin. This forms the coil unit 100 as shown in Figure 8. The insulating resin coating is performed, for example, by electrodeposition coating. Each circumference of the spiral of the rectangular wire coils 12A to 12C is separated by molding after annealing, allowing sufficient contact between the coating liquid and the entire spiral structure (the surface of a long conductor). As a result, each one-circle region CR of the spiral structure of the rectangular wire coils 12A to 12C is insulated from each other. The insulating resin coating may also be applied by spraying insulating resin material or by injection molding of insulating resin.

[0095] In the second embodiment, a configuration in which three flat wire coils 12A to 12C are connected is illustrated, but the number of connected flat wire coils 12 (original round wire coils 11) is not limited to this example. For example, a configuration in which five flat wire coils 12 (original round wire coils 11) are connected at the connecting section 300 is also possible.

[0096] Furthermore, the process of forming the second coil unit (flat wire coil unit) 102 (step S13) may be performed after the deformation process of the connecting portion 300 (step S15). That is, after forming the first coil unit 101 (step S11), the connecting portion 300 may be deformed (step S15) to position each coil in the desired position, and then pressed to form the second coil unit 102 (step S13).

[0097] Furthermore, although not shown in the diagram, an external connecting member is connected to at least one of the lead-out sections TO1 and TO2 of the coil unit 100 (or flat wire coil unit 102) as needed. The external connecting member is, for example, a terminal or a busbar. The external connecting member and the lead-out sections TO1 and TO2 can be joined, for example, by pressure welding (cold pressure welding) where the end faces of both are butted together and pressed. This joining may also be done by welding or bonding with a conductive adhesive. The external connecting member may be made of the same metal material (for example, a metal material mainly composed of aluminum) as the round wire conductor M0 (for example, a metal material mainly composed of aluminum), or it may be made of a different metal material (for example, a metal material mainly composed of copper (copper or a copper alloy, etc.)). For example, the lead-out sections TO1 and TO2 may be made sufficiently long and deformed into a desired shape by bending the connecting section 300, and this may be used as the external connecting member (for example, a busbar). In this way, a coil unit 100 with a busbar can be formed without separately connecting an external connecting member.

[0098] When connecting external connection members to the lead-out sections TO1 and TO2 at a later stage, it is preferable to do so, for example, before coating with insulating resin. Alternatively, after coating with insulating resin, the insulating resin can be peeled off from the lead-out sections TO1 and TO2 and then the connections can be made.

[0099] <Stator component> Figure 15 shows an example of a stator member 800 constructed by connecting multiple sets (four sets in this case) of the above-described coil units 100. Figure (A) is a front view of a single flat wire coil 12 as seen from the axial direction of the spiral, and Figure (B) is a perspective view.

[0100] The four sets of coil units 100 (100A to 100B) are connected by a connecting section (busbar) 400. The connecting section 400 can be made of a conductor continuous with the four sets of coil units 100, for example. That is, by making the number of coils that can be molded with one set of molding dies 61 (see Figure 11) 12, they can be formed in the same manner as described above. Specifically, one round wire conductor M0 is wound to form four sets of round wire coil units 101, each set of three. In each round wire coil unit 101, as shown in Figure 10, three round wire coils 11 are wound so that they are continuous via a connecting section 300 of a predetermined length. Furthermore, each of the four sets of round wire coil units 101 is wound so that they are continuous via a connecting section (busbar) 400 of a predetermined length.

[0101] Then, molding is performed using a set of molding dies 61, and the connecting portion 300 is deformed to form four sets of flat wire coil units 102. Furthermore, the connecting portion 400 is deformed as needed. This forms a stator member 800 in which four sets of coil units 100 (100A to 100B) are connected by the connecting portion (bus bar) 400, as shown in the figure. In this case, the connecting portion 400 is made of the same material as, for example, the coil units 100.

[0102] Alternatively, the stator member 800 may be formed by connecting four sets of flat wire coil units 102, each individually formed using the molding die 61 shown in Figure 11 (a die capable of forming a flat wire coil unit 102 consisting of three flat wire coils 12), with a connecting portion 400 that serves as an external connecting member, by pressure welding or the like. In this case, the connecting portion 400 (external connecting member) connects to the respective output portions TO of the four sets of coil units 100 (100A to 100B). In this case, the connecting portion 400 may be made of the same material as the coil unit 100 or of a different material (for example, copper).

[0103] In either case, the connecting portion 300 and the connecting portion 400 are protected from pressure by spacers or covers (not shown) provided on the mold.

[0104] Furthermore, when forming such a stator member 800, the insulating resin coating process (step S19) may be performed after forming multiple sets of continuous flat wire coil units 102 (after connecting the multiple sets of flat wire coil units 102).

[0105] By forming multiple of these stator members 800 and attaching them to an annular stator core (not shown), a stator is constructed in which multiple flat wire coils 12 are arranged in an annular shape. For example, by making the current or voltage phases of the three flat wire coils 12A to 12C (or each coil unit 100) that constitute a set of coil units 100 different, for example, U-phase, V-phase, and W-phase, a stator member 800 for a three-phase motor can be manufactured.

[0106] The stator member 800 shown in Figure 15 is used in a radial gap type motor where the helical axis AX direction of the flat wire coil 12 is perpendicular to the axial direction of the motor. However, it is not limited to this, and according to the manufacturing method of the coil unit 100 of this embodiment, by appropriately changing the shape (winding method, arrangement) of the round wire coil unit 101 shown in Figure 10, etc., and the deformation of the connecting portion 300 shown in Figure 12, etc., it is also possible to form a stator member used in an axial gap type motor where the helical axis AX direction of the flat wire coil 12 is parallel to the axial direction of the motor.

[0107] The above-described examples (first and second embodiments) describe the case where the first coil shape is a round wire coil 11 and the second coil shape is a flat rectangular wire coil 12. However, the first and second coil shapes are not limited to the above example, as long as the conductor cross-sectional shape and / or size (cross-sectional area) of the coils are different. This will be explained below.

[0108] Figure 16 is a schematic diagram illustrating the first coil shape C1 and the second coil shape C2 of this embodiment, and is a schematic cross-sectional view corresponding to line XX in Figure 2(B). In Figures 16(A) to (D), the left side is an example of the first coil shape C1, and the right side is an example of the second coil shape C2.

[0109] Figure 16(A) shows an example of the above-described embodiment. Specifically, a round wire coil 11 with a roughly circular cross-sectional shape of the conductor is used as the first coil shape C1, and this is pressed by molding dies 51 and 61 to form a flat wire coil 12 with a roughly rectangular cross-sectional shape of the conductor, which is the second coil shape C2.

[0110] Figure 16(B) shows another example in which a round wire coil 11 with a roughly circular cross-sectional shape of the conductor is used as the first shape coil C1, and this is pressed by molding dies 51 and 61 to form a flat round wire coil with an oval (elliptical) cross-sectional shape of the conductor as the second shape coil C2.

[0111] Figure 16(C) shows another example in which a flat round wire coil with an oval (elliptical) cross-sectional shape of the conductor is used as the first coil shape C1, and this is pressed by molding dies 51 and 61 to form a flat rectangular wire coil with a roughly rectangular cross-sectional shape of the conductor as the second coil shape C2.

[0112] Figure 16(D) shows another example in which a thick, roughly rectangular (or polygonal) rectangular wire coil is used as the first coil shape C1, and this is pressed by molding dies 51 and 61 to form a second coil shape C2, which is a flat rectangular wire coil 12 with a roughly rectangular (or polygonal) cross-sectional shape.

[0113] Note that the external shapes of the first coil C1 and the second coil C2 are not limited to those shown in Figure 16; in either case, they may be roughly rectangular or roughly truncated square pyramidal.

[0114] As described above, according to this embodiment, for example, a round wire conductor M0 can be wound in a spiral shape and pressed in the direction of the spiral axis AX by a molding die to form a highly accurate rectangular flat wire coil 12 in plan view. A rectangular flat wire coil 12 in plan view (with corners that are approximately right angles in plan view) can improve the space utilization when mounted on a stator, contributing to the high performance of the motor. In other words, a flat wire coil 12 suitable as a motor component can be manufactured with simple equipment and processes without requiring complex processes or devices, thereby reducing manufacturing costs and improving productivity (mass production speed).

[0115] Furthermore, at least a portion of the connecting portion 300 and / or the connecting portion 400 may be pressed (similarly to the coil).

[0116] Furthermore, in the process of forming the rectangular wire coil unit (second shape coil unit) 102, an example was given in which three round wire coils (first shape coils) 11A to 11C are pressed at the same time using, for example, the molding die 61 shown in Figure 11. However, this is not limited to this, and the three round wire coils 11A to 11C may be pressed at different timings. Specifically, for example, a molding die capable of forming one rectangular wire coil 12 may be used, and the three round wire coils 11A to 11C may be individually and sequentially set in the molding die and pressed to form the rectangular wire coil unit 102.

[0117] To reiterate, the conductor in this embodiment (for example, the round wire conductor M0) is, for example, a metal material mainly composed of copper or a metal material mainly composed of aluminum. The conductor may be constructed by connecting multiple metal materials in the longitudinal direction, for example, by pressing a metal material mainly composed of copper and a metal material mainly composed of aluminum together at their end faces (repeating this once or multiple times) to form a single conductor. In other words, the material may change to a different metal material during the circumference of the coil (first shaped coil C1, round wire coil 11). Furthermore, the multiple coils constituting the coil unit 100 may be made of different metal materials.

[0118] Furthermore, when forming the first-shaped coil C1 (round wire coil 11) into the second-shaped coil C2 (flat rectangular wire coil 12), multiple pressing processes may be performed using two or more molding dies of different shapes and sizes.

[0119] Furthermore, in the above embodiment, the first coil shape C1 (round wire coil 11) and the second coil shape C2 (flat wire coil 12) are shown as examples of concentrated-winding coils in which the conductor is wound in a spiral shape. However, the embodiment is not limited to this, and may also be a so-called distributed-winding or wave-winding coil in which the circumferential region (one-turn region CR) around a virtual axis is wound in one direction (for example, the circumferential direction of the stator).

[0120] Furthermore, the present invention is not limited to the embodiments described above, and does not deviate from the spirit of the present invention. Of course, various changes can be made within the limits of what is permitted. [Explanation of Symbols]

[0121] 11 Round wire coil 11A First Round Wire Coil 11B Second Round Wire Coil 11C Third Round Wire Coil 12 Flat wire coils 12A First Flat Rectangular Wire Coil 12B Second Flat Wire Coil 12C Third Flat Rectangular Wire Coil 51, 61 Molding dies 100 coil units 101 First Shape Coil Unit (Round Wire Coil Unit) 102 Second-type coil unit (flat wire coil unit) 300 Connection part 400 Connection (bus bar) 510 Base section 511 First mold (upper mold) 512 Second mold (lower mold) 513 Recess 513A Pressing surface 514 Base section 515 shaft 516 Base section 517 Pressing part 518 recess 519 Shaft 520 Base section 550 Molding area 551 Short side 552 Long side 553 Corner 610 Base section 611 First Mold 612 Second mold 613 recess 614 Base section 615 Shaft 800 Stator component A1 Helical axis direction A2 Helical axis cross plane direction AX Virtual Axis (Spiral Axis) C1 First Shape Coil C2 Second Shape Coil

Claims

1. A method for manufacturing a coil using a molding die having a first mold and a second mold that are relative to each other, The molding die has a roughly rectangular frame shape in a plan view, where the molding region partitioned by the first die and the second die has short sides, corners, and long sides. The width of the corner portion is set to be greater than the width of the short side portion and the width of the long side portion. The steps include winding a round wire conductor to form a round wire coil, The step includes accommodating the round wire coil in the molding region and pressing it with the molding die to form a flat wire coil with a substantially rectangular circumference, The amount of pressure applied by the molding die is such that the metal material of the conductor spreads sufficiently to at least the corners. A method for manufacturing a coil characterized by the following:

2. The process includes the step of covering the surface of the rectangular wire coil with an insulating resin. The method for manufacturing a coil according to claim 1.

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