Coil unit

Abstract

To provide a coil unit that is smaller and can be manufactured in a simplified manufacturing process.SOLUTION: A coil unit 10 connects a coil 11 and a bus bar 13, and the bus bar 13 includes a wiring portion 13A and a connecting portion 13B connected to an end portion 11A of the coil 11, which are integrally formed of a flat conductor. The connecting portion 13B and the end portion 11A are joined by butting their end surfaces together, the connection portion 13B includes a straight line area, the connecting portion 13B is bent with respect to the wiring portion 13A such that an extending direction of the straight line area and an extending direction of the wiring portion 13A are different from each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coil unit. [Background technology]

[0002] Conventionally, edgewise coils have been known that are formed by laminating steel sheets produced by stamping, and are used, for example, in the stators of motors.

[0003] In this case, the stator is formed by sequentially fitting pre-formed coils (edgewise coils) into multiple slots (teeth) provided on the inner surface of an annular stator core, and connecting one end of each of the annularly arranged coils to a bus bar.

[0004] More specifically, one end (terminal end) of each of the annularly arranged coils protrudes axially upward from the stator core, and this end is connected by welding or the like to a rod-shaped (arc-shaped) or annular bus bar extending in the circumferential direction of the stator core. For example, in the case of a three-phase motor, the coils are fitted into slots so that the U-phase, V-phase, and W-phase coils are arranged adjacent to each other in the circumferential direction of the stator core, and bus bars are connected to one end of every third coil in the circumferential direction for the U-phase, V-phase, and W-phase (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-89456 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in conventional connection methods, the coils are arranged in a ring shape, and then the ends of the coils that protrude upward are connected to a ring-shaped bus bar. This means that the connection method is limited to welding or screwing, and the structure of the joint is complicated, which limits the miniaturization of the completed stator. In addition, there is also the problem that the connection device becomes large, making the connection work complicated.

[0007] In view of the above circumstances, the present invention aims to provide a coil unit that is compact and has a simplified manufacturing process. [Means for solving the problem]

[0008] The present invention relates to a coil unit in which a coil and a bus bar are joined together, and the bus bar is No. a wiring portion and a connection portion connected to an end of the coil are integrally formed by a conductor having one surface, The connection portion and the end portion are joined by joining end surfaces together, and the bus bar is The connection portion from the wiring portion throughout the The aforementioned No. One surface is located in approximately the same plane, a second surface in a joining region between the connection portion and the end portion and a third surface in the end portion are positioned on substantially the same plane as the first surface, Applicable No. The coil unit is characterized in that the coil and the bus bar are joined together with one surface and each of the areas of one circumference of the coil being approximately parallel to each other. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a coil unit that is miniaturized and whose manufacturing process is simplified. [Brief explanation of the drawings]

[0010] [Figure 1] 1A to 1C are diagrams showing a coil unit of the present embodiment, in which (A) is an external perspective view, (B) is a front view, and (C) is a top view. [Figure 2] 1A to 1C are diagrams showing a bus bar according to the present embodiment, in which (A) is a top view, (B) is a front view, and (C) is a side view. [Figure 3]1A to 1C are diagrams showing the coil of this embodiment, including (A) an external perspective view, (B) a front view, (C) a rear view, (D) a side view, (E) a top view, (F) a front view, and (G) a cross-sectional view of (F). [Figure 4] 2A to 2C are diagrams showing a stator member of the present embodiment, in which (A) is an external perspective view, (B) is a front view, and (C) is a top view. [Figure 5] 1A to 1C are diagrams showing a coil unit of the present embodiment, in which (A) is an external perspective view, (B) is a front view, and (C) is a top view. [Figure 6] 1A to 1C are diagrams showing a coil unit of the present embodiment, in which (A) is an external perspective view, (B) is a front view, and (C) is a top view. [Figure 7] 1A to 1C are diagrams showing a coil unit of the present embodiment, in which (A) is an external perspective view, (B) is a front view, and (C) is a top view. [Figure 8] 1A is a top view showing a stator of this embodiment, FIG. 1B is an enlarged view of a part of FIG. 1A, and FIG. 1C is an exploded side view of the motor. [Figure 9] 1A to 1C are diagrams illustrating a method for manufacturing a coil according to the present embodiment. [Figure 10] 5A to 5C are diagrams illustrating a manufacturing method of the coil unit according to the present embodiment. [Figure 11] 5A to 5C are diagrams illustrating a manufacturing method of the coil unit according to the present embodiment. [Figure 12] 5A to 5C are diagrams illustrating a manufacturing method of the coil unit according to the present embodiment. [Figure 13] 5A to 5C are diagrams illustrating a manufacturing method of the coil unit according to the present embodiment. [Figure 14] 5A to 5C are diagrams illustrating a method for manufacturing the stator according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <Coil unit> FIG. 1 is an external view of a coil unit 10 according to this embodiment, with (A) being a perspective view, (B) being a front view, and (C) being a top view. As shown in FIG. 1, the coil unit 10 according to this embodiment includes a coil 11 and a bus bar 13 connected thereto. More specifically, the bus bar 13 includes, for example, a wiring portion 13A having a substantially annular shape (e.g., a circular or polygonal shape) and a connection end portion 13B (hereinafter referred to as the "coil connection end portion 13B") extending from the wiring portion 13A and connecting to the coil 11. In this embodiment, the assembly of the coil 11 and the bus bar 13 shown in FIG. 1 is referred to as the coil unit 10.

[0012] 2A and 2B are diagrams showing the bus bar 13 before joining, in which (A) is a plan view (top view) after punching, (B) is a front view of only the bus bar 13 extracted from the coil unit 10 shown in FIG. 1, and (C) is a side view (as viewed from the tip side of the connection end 13B in (B)).

[0013] Busbar 13 is formed by, for example, punching a circular wiring portion 13A and a coil connection end portion 13B integrally from a metal member (for example, a copper plate) etc. Connection end portion 13B is punched out so as to extend from wiring portion 13A in its outer circumferential direction (direction from the central axis of circular wiring portion 13A toward the outside).

[0014] The coil connection end 13B is rectangular in plan view (FIGS. 2A and 2B), and as shown in FIG. 2C, the end face 13S (cross section perpendicular to the longitudinal direction) at its tip end is also rectangular. More specifically, the coil connection end 13B has two opposing wide faces WS and two opposing narrow faces WT, and is a strip-shaped member that is long in a predetermined direction. The cross section perpendicular to the strip longitudinal direction BL (cross section taken along line AA in FIG. 2A), i.e., the end face 13S, is rectangular or rounded rectangular as shown in FIG. 2C. In the following explanation, the case where the cross section perpendicular to the strip longitudinal direction BL (end face 13S) is rectangular (upper view of FIG. 2C) is described as an example.

[0015] The wiring portion 13A is provided with an external terminal 13C for connecting to, for example, an external battery. Like the coil connection end portion 13B, the external terminal 13C is formed integrally with the wiring portion 13A by punching, and is then bent into a desired shape for the coil unit 10 (FIG. 1B).

[0016] FIG. 3 shows coil 11, where (A) is an external perspective view, (B) is a front view of coil 11 seen from the axial center direction of its spiral structure, (C) is a rear view, (D) is, for example, a left side view of (B), (E) is a top view of (B), (F) is a front view showing one end 11A of coil 11 extracted, and (G) is a cross-sectional view along line BB of (F).

[0017] The coil 11 is a so-called edgewise coil made by winding a flat conductor, and both ends 11A and 11B have the shape of a flat conductor. Specifically, the coil 11 is formed by pressure-welding multiple strip-shaped flat conductors to form a spiral structure. As will be described in detail later, multiple flat conductors, each of which has a length equal to or less than the length of one turn region CR of the spiral structure (a rectangular one-turn region shown in Figure 1B), are pressed (cold-welded) together at their straight portions along the strip longitudinal direction BL to form a substantially rectangular one-turn region CR, which is then connected to form the spiral structure with the desired number of turns. In other words, both ends 11A and 11B of the coil 11 are part of the multiple flat conductors that make up the spiral structure.

[0018] In this embodiment, one end 11A of the two ends of the coil 11 is an end that connects to the bus bar 13 (hereinafter referred to as the "bus bar connection end 11A"), and is located midway around the one-turn region CR of the spiral structure of the coil 11 (midway along the long side of the rectangular one-turn region CR) as shown in Figures 1A and 1B. The other end (other end) 11B is configured to be located (led out) outside the spiral structure, specifically on an extension of the long side of the one-turn region CR.

[0019] As shown in Figures 1F and 1G, the bus bar connection end 11A of the coil 11 also has two opposing wide faces WS and two opposing narrow faces WT, and is a strip-shaped member that is long in a predetermined direction, and the cross section perpendicular to the strip longitudinal direction BL (cross section taken along line BB in Figure 1F), i.e., the end face 11S, is rectangular or rounded rectangular as shown in Figure 1G. In the following explanation, the case where the cross section perpendicular to the strip longitudinal direction BL (end face 11S) is rectangular (upper view of Figure 1G) is used as an example.

[0020] 1 and 2 is configured to have a shape (size) that matches the shape of the flat conductor of busbar connection end 11A of coil 11. Specifically, end face 11S (a surface perpendicular to the spiral direction of the spiral structure) of busbar connection end 11A and end face 13S of coil connection end 13B of busbar 13 are configured to have rectangular shapes and the same size (substantially matching rectangular shapes) so that the shape of end face 11S and end face 13S substantially matches the shape of end face 13S.

[0021] 1, the coil connection end 13B and the bus bar connection end 11A are joined by cold pressure welding with their end faces (end face 11S and end face 13S) butted together to form the coil unit 10. In the coil unit 10, the bus bar 13 and the coil 11 are integrally coated with a resin.

[0022] The joint CP between the coil connection end 13B and the busbar connection end 11A is located midway around the spiral structure of the coil 11. More specifically, the coil 11 and the busbar 13 are connected so that the joint CP is located on a straight portion of the flat conductor that constitutes the spiral structure of the coil 11 (for example, a straight portion of the flat conductor that constitutes the long side of the rectangular one-turn region CR of the spiral structure). For ease of explanation, the joint CP is clearly shown in each drawing of this embodiment, but because cold pressure welding is an atomic bonding of metals, the joint CP is securely joined to the extent that the positions of the end faces 11S and 13S are not visible to the naked eye.

[0023] In this example, one coil 11 is connected to one bus bar 13, but any number of coils 11 may be connected. In this case, coil connection ends 13B of the bus bar 13 are provided corresponding to the number of coils 11. For example, a coil unit 10 of a certain phase (single phase) is configured by connecting a plurality of coils 11 of the same structure in the circumferential direction of the wiring portion 13A of the bus bar 13.

[0024] With this configuration, the joint CP between the busbar 13 and the coil 11 is simply formed by butting the end face 11S of the busbar connection end 11A and the end face 13S of the coil connection end 13B together, which allows the joint CP to be kept to the minimum necessary size. In other words, the coil unit 10 can be made smaller than in a conventional structure in which the two are connected by welding, screws, or the like.

[0025] Furthermore, in this embodiment, since the joint CP can be located midway around the spiral structure of the coil 11, the vicinity of the upper end of the coil 11 and the wiring portion 13A of the busbar 13, which was the joint between the busbar and the coil in the past (near the dotted circle in FIGS. 1A and 1B), can be formed only by the bent structure of the coil connection end 13B of the busbar 13. In other words, compared to the past structure in which the joint was located at this position (the upper end of the coil 11), the upper end of the coil 11 can be made the minimum necessary size, which also enables the coil unit 10 to be made more compact. <Stator component> Next, the stator member 20 of this embodiment will be described with reference to Figures 4 to 7. Here, as an example, the case of a stator member 20 that constitutes a three-phase motor will be described.

[0026] FIG. 4 shows the stator member 20, where (A) is an external perspective view, (B) is a front view, and (C) is a top view. FIG. 5 shows the U-phase coil unit 10, where (A) is an external perspective view, (B) is a front view, and (C) is a top view. FIG. 6 shows the V-phase coil unit 10, where (A) is an external perspective view, (B) is a front view, and (C) is a top view. FIG. 7 shows the W-phase coil unit 10, where (A) is an external perspective view, (B) is a front view, and (C) is a top view.

[0027] 4, the stator member 20 constituting the three-phase motor is a combination of three coil units 10 (the above-mentioned coil units 10) with the same number of turns, arranged at equal intervals (120°) from each other. The three coil units 10 are, for example, a U-phase coil unit 10U, a V-phase coil unit 10V, and a W-phase coil unit 10W.

[0028] Referring to FIG. 5, U-phase coil unit 10U has a plurality of (for example, three) coil connection ends 13BU spaced apart in the circumferential direction of wiring portion 13AU of busbar 13U.

[0029] The coil connection ends 13BU are provided at predetermined distances in the circumferential direction of the annular wiring portion 13AU. Specifically, they are provided at equal intervals at positions 120° apart from one another on the annular wiring portion 13AU. Each of the coil connection ends 13BU has the same configuration as that shown in FIGS. 2 and 3, except for the number of coil connection ends 13BU. The multiple coils 11U (bus bar connection ends 11AU) having the same configuration (number of turns) are connected to the multiple coil connection ends 13BU, respectively.

[0030] Furthermore, a neutral point connection terminal 15 is provided at the other end 11BU of each coil 11U by welding or the like. Each neutral point connection terminal 15 is provided so as to be located outside (lead out from) the spiral structure of each coil 11U and is connected to the neutral point. The external terminal 13CU is bent into a desired shape.

[0031] The V-phase coil unit 10V shown in Figure 6 and the W-phase coil unit 10W shown in Figure 7 have the same configuration as the U-phase coil unit 10U, but the positions of the respective coil connection ends 13BV, 13BW and the positions of the external terminals 13CV, 13CW are set in different positions (shifted positions) so as not to interfere with each other in the three coil units 10U, 10V, 10W (see Figure 4).

[0032] Then, as shown in Figure 4, these three coil units 10U, 10V, and 10W are combined so that the current or voltage phases are different from one another. At this time, the bus bars 13U, 13V, and 13W of the three coil units 10U, 10V, and 10W, respectively, are stacked so that their central axes are aligned.

[0033] In each of the three coil units 10U, 10V, and 10W, the coils 11 and bus bars 13 are integrally coated with insulating resin in the state shown in FIGS. 5 to 7 (before assembly). That is, for example, the coil unit 10U is immersed in liquid insulating resin to integrally coat it with the insulating resin. As a result, the coil 11 of the coil unit 10U is covered with insulating resin for each region CR of the spiral structure (the Nth and N+1th turns are insulated). Note that the coil unit 10U may also be integrally coated with insulating resin by spraying liquid insulating resin onto it. Then, the coil units 10U, 10V, and 10W coated with insulating resin are combined as shown in FIG. 4 to form the stator member 20. <Stator and motor> FIG. 8 is a diagram showing an outline of a stator 35 (FIGS. 8A and 8B) using the stator member 20 of this embodiment, and a three-phase motor 30 (FIG. 8C) using the same. FIG. 8A is a schematic top view of the stator 35 as seen from the axial direction, and FIG. 8B is a schematic top view showing a portion of FIG. 8A, with the busbar 13 omitted in both figures. FIG. 8C is an exploded side view of the three-phase motor 30.

[0034] As shown in Figures 8(A) and 8(B), the stator 35 includes, for example, a cylindrical stator core 351, a plurality of cassettes 352, and the above-mentioned stator member 20. The stator member 20 of this embodiment is attached to the stator core 351 afterward. As will be described in detail later, the stator 35 is configured by attaching a cassette 352 to each of the plurality of coils 11 arranged in an annular shape that constitutes the stator member 20 shown in Figure 4, and then attaching these to the stator core 351. Note that although only three coils 11 are shown in Figures 8(A) and 8(B), the coils 11 to which the cassettes 352 are attached are arranged all around the stator core 351.

[0035] Furthermore, as shown in FIG. 1C, a rotor 33 is rotatably assembled to the stator 35 to obtain a three-phase motor 30. Specifically, the three-phase motor 30 includes, for example, a shaft 31, a housing 32, a rotor 33, and a stator 35. The shaft 31 is a columnar member, and rotates about its central axis while being supported by, for example, a bearing 34 provided in the housing 32. A device to be driven (not shown) is connected to one end of the shaft 31 via a power transmission mechanism such as a gear.

[0036] The rotor 33 has magnets (not shown) arranged around its circumference and rotates together with the shaft 31. The stator 35 is arranged, for example, radially outside the rotor 33 and generates a force to rotate the rotor 33. External terminals 13CU, 13CV, and 13CW (see FIG. 4) of the stator 35 are connected to a drive circuit or power supply (neither of which is shown) that supplies power to the motor via, for example, lead wires.

[0037] In three-phase motor 30, when a driving current is applied to coil 11 from a power supply or a driving circuit via bus bar 13, magnetic flux is generated in cassette 352 of stator 35. Then, the action of the magnetic flux between cassette 352 and a magnet (not shown) generates a circumferential torque. As a result, rotor 33 rotates around the central axis relative to stator 35.

[0038] Although the present embodiment has been described using an example of a three-phase motor 30 and the stator member 20 constituting the motor, the stator member 20 of a single-phase motor can be obtained by connecting multiple coils 11 of the same structure so that they are adjacent to each other in the circumferential direction of the wiring portion 13A of one bus bar 13. For example, nine coil connection ends 13B are provided at equal intervals along the circumferential direction of the wiring portion 13A of the bus bar 13 shown in FIG. 5, and the bus bar connection ends 11A of the coils 11 are connected to these ends, respectively. This results in a single-phase stator member 20 (which can also be called a coil unit 10) in which nine coils 11 are connected adjacent to each other in the circumferential direction of the wiring portion 13A of one bus bar 13, as shown in FIG. 4. Furthermore, a single-phase motor can be obtained by rotatably assembling a rotor 33 to a stator 35 having the single-phase stator member 20. <Manufacturing method of coil unit> Hereinafter, a method for manufacturing the U-phase coil unit 10U will be described as an example with reference to Fig. 9 to Fig. 15. First, Fig. 9 is a schematic diagram showing an example of a manufacturing method for the coil 11 of this embodiment, in which Fig. 9(A) is a plan view showing the flat conductors 111 that form one circumference region CR of the coil 11, and Fig. 9(B) is a development view illustrating the process of joining the flat conductors 111. Also, Figs. 10 to 15 are diagrams illustrating a manufacturing method for the bus bar 13 and the coil unit 10U.

[0039] 9, the coil 11 of this embodiment is formed by continuously pressing strip-shaped flat conductors 111 together to form a helical structure. Specifically, the coil 11 is manufactured by the method disclosed in Japanese Patent Publication No. 5592554, which is a patent owned by the applicant of the present application. Briefly, as shown in FIG. 9A, a plurality of flat conductors 111 are prepared, each having a length equal to or less than the length of one circumference region CR of the helical structure. Each of the flat conductors 111 is punched into a U-shape from a copper plate or the like, and a virtual helical structure (virtual helical structure) can be formed by butting the end faces 111S of the flat conductors (the end faces perpendicular to the longitudinal direction of the strip (the short side direction)) together. This virtual spiral structure is configured so that the length of a one-circle region CR', which is composed of a half-circle in one direction of the spiral progression (the half-circle shown by the dotted line of the upper flat conductor 111 in Figures (A) and (B)) and a half-circle in the other direction (the half-circle shown by the dotted line of the lower flat conductor 111 in Figures (A) and (B)) based on the point where the end faces 111S of the two flat conductors 111 butt against each other, is longer than the length of the one-circle region CR of the spiral structure that becomes the coil 11 (left diagram in Figure (A)) by the amount of pressure applied by the crimping.

[0040] Then, as shown in Fig. 1B, the end faces 111S of the respective straight portions of the flat conductors 111 are pressed together along the strip longitudinal direction, and the end faces 111S are joined together while shortening the distance along the strip longitudinal direction to form the connecting flat conductors, and the length of the one-turn region CR of the connecting flat conductors is made to match the length of the one-turn region CR of the helical structure. This results in a coil 11 in which the one-turn region CR of the helix has a rectangular shape with short and long sides when viewed from the central axis of the helical structure.

[0041] Although the figure illustrates a case in which the flat conductors 111 have the same shape, the flat conductors 111 may have different shapes of wide faces WS and narrow faces WT, provided that the shapes of the butting end faces 111S are the same. That is, in a single flat conductor 111, the wide faces WS may be gradually narrower (wider) and the narrow faces WT may be gradually thicker (thinner) in the strip longitudinal direction (spiral progression direction). In the coil 11 shown in FIG. 3, the flat conductors 111 are configured such that the wide faces WS are gradually narrower and the narrow faces WT are gradually thicker from end 11A to end 11B (the shapes of the butting end faces 111S are the same). Furthermore, the shapes of the butting flat conductors 111 are not limited to the same U-shape, but may be C-shape and I-shape, etc.

[0042] 3, the coil 11 has a starting end (end 11A) and a terminal end (end 11B) of its helical structure at different positions in the spiral direction. That is, one end, i.e., the busbar connection end 11A, is located midway around the one-turn region CR of the helical structure, specifically midway along the long side of the rectangular one-turn region CR, and the other end (other end) 11B extends (protrudes) from the helical structure in the direction of the busbar 13 when the coil unit 10 is configured (upward when the coil unit 10 is configured on the short side of the coil 11, upward in the axial direction of the stator core 351).

[0043] 10(A), the bus bar 13 (13U) is first cut out as a flat plate-like body integrating the annular wiring portion 13A (13AU), the coil connection end portion 13B (13BU), and the external terminal 13C (13CU) by punching out a plate-like metal member (e.g., a copper plate) F. The coil connection end portion 13B is punched out into a rectangular shape (strip shape) so as to extend from the wiring portion 13A in its outer circumferential direction (in the direction from the central axis of the annular wiring portion 13A toward the outside).

[0044] In this example, three coils 11 are connected to the bus bar 13, so three coil connection ends 13B are formed around the wiring portion 13A at equal intervals (120°) and extend radially. As shown in Fig. 2, the coil connection end 13B is rectangular in plan view, and its tip end face 13S (cross section perpendicular to the longitudinal direction) is also rectangular. The external terminal 13C (13CU) is formed at a position different from that of the coil connection end 13B.

[0045] Immediately after punching, the wiring portion 13A, the coil connection end portion 13B, and the external terminal 13C are in a flat plate shape positioned on approximately the same plane as shown in Fig. 1B. Then, the bus bar 13 and the coil 11 are joined by cold pressure welding.

[0046] 11 is a front view showing a schematic of a cold pressure welding apparatus (cold pressure welding apparatus) 100. The pressure welding apparatus 100 has, for example, a first holding unit 101 and a second holding unit 102 that can move toward or away from each other in the horizontal direction (the X-axis direction in the figure). The first holding unit 101 has, for example, a first upper holding body 101U and a first lower holding body 101D that open and close in the vertical direction (the Y-axis direction in the figure), and these members clamp, for example, the wide surface WS of the coil connection end 13B of the bus bar 13. The second holding unit 102 also has, for example, a second upper holding body 102U and a second lower holding body 102D that open and close in the vertical direction (the Y-axis direction in the figure), and these members clamp, for example, the wide surface WS of the bus bar connection end 11A of the coil 11.

[0047] In other words, the first holding portion 101 maintains a flat shape such that the wiring portion 13A and the coil connection end portion 13B of the busbar 13 are positioned in approximately the same plane, and holds one of the coil connection ends 13B, and the second holding portion 102 holds the busbar connection end portion 11A so that the end face 11S of the busbar connection end portion 11A of the coil 11 faces the end face 13S of the coil connection end portion 13B of the busbar 13 (same figure (A)).

[0048] The pressure welding device 100 moves the first holding part 101 and the second holding part 102 so that they approach each other (in this example, they are moved toward the center along the X-axis direction in the figure), and then butts the end face 13S of the coil connection end part 13B and the end face 11S of the busbar connection end part 11A together, and joins them by cold pressure welding (FIG. 1B). As a result, the position where the end faces 11S and 13S butt together becomes a joint CP, and the joint CP is located midway around the spiral structure of the coil 11, specifically, midway along the long side of the rectangular one-turn region CR. Here, the longitudinal lengths of the busbar connection end part 11A and the coil connection end part 13B before joining are set to be longer by an additional margin than the lengths after joining, so that the joint CP between the coil 11 and the busbar 13 is located midway around the one-turn region CR. Then, by setting the distance shortened by cold pressure welding to the margin, the joining is performed so that the joint CP is positioned midway around the one-round region CR (see FIG. 9(A)).

[0049] In this embodiment, the joint CP is located near the center of the long side of the one-turn region CR of the coil 11, but is not limited to this and may be located higher or lower than shown in the figure. Also, the joint CP does not have to be located at a position protruding (leading out) from the coil 11, as long as it is located midway around the one-turn region CR, and may be located on the short side of the one-turn region CR, for example.

[0050] After pressing, in the first holding portion 101, the first upper holding body 101U and the first lower holding body 101D move apart along the Y-axis direction, and in the second holding portion 102, the second upper holding body 102U and the second lower holding body 102D move apart along the Y-axis direction, respectively, thereby releasing the clamping of the bus bar 13 and the coil 11, and the first holding portion 101 and the second holding portion 102 move apart along the X-axis direction and return to their initial positions.

[0051] Although the cold pressure welding apparatus 100 can cold-weld both parts with a single press, it is desirable to repeat pressing multiple times for one joint to stabilize the joint surface. As an example, a stable joint surface can be obtained by repeatedly pressing (cold welding) one joint CP three to four times, compressing it by about 1 mm or more (preferably 1.5 mm or more, specifically about 2 mm).

[0052] After cold welding the coil 11 and the bus bar 13, burrs are generated at the joint CP due to extrusion. Therefore, after cold welding is completed, the coil 11 and the bus bar 13 are removed from the holding part and the burrs are removed, and then cold welding is performed between the bus bar connection end 11A of another coil 11 and the other coil connection end 13B of the bus bar 13.

[0053] FIG. 12 is a diagram showing the coil 11 and bus bar 13 after joining, in which FIG. 12(A) is a plan view, FIG. 12(B) is a side view, and FIG. 12(C) is an external perspective view of the coil unit 10 (10U).

[0054] Coils 11 are joined in the same manner to each of the three coil connection ends 13B of busbar 13, thereby obtaining a joined assembly of coil 11 and busbar 13 shown in Fig. 12(A). In this state, as shown in Figs. 12(A) and 12(B), coil 11 and busbar 13 are arranged on a substantially flat surface so that the central axis direction of the spiral structure of coil 11 (the direction of first central axis C1) and the central axis direction of wiring portion 13A of busbar 13 (the direction of second central axis C2) are aligned.

[0055] Thereafter, as shown by the arrows in Fig. 1B, the coils 11 are bent relative to the bus bar 13 so that the first central axis C1 of each coil 11 intersects with the direction of the second central axis C2 of the bus bar 13. As a result, the direction of the second central axis C2 of the bus bar 13 and the direction of the long side of the one-turn region CR of the coil 11 are aligned in the same direction, and a coil unit 10U is formed in which the wiring portion 13A of the bus bar 13 is located above the coil 11 (above the upper short side of the one-turn region CR) (Fig. 1C).

[0056] Thereafter, the coil 11 and the bus bar 13 are integrally coated with insulating resin. Specifically, the coil unit 10U is immersed in, for example, liquid insulating resin to be integrally coated with the insulating resin. Alternatively, the coil unit 10U may be integrally coated with the insulating resin by spraying the liquid insulating resin onto the coil unit 10U.

[0057] Conventionally, coils coated with insulating resin are connected to bus bars by welding or screwing, and the bus bars are insulated from each other by sandwiching an insulating resin layer between them. Alternatively, the coil and bus bar are each coated with insulating resin separately except for the joint, and then the joint is coated with insulating resin again after connecting the two. This makes the structure complicated, requiring, for example, a holder for the insulating resin layer, and the manufacturing process cumbersome.

[0058] However, in this embodiment, the coil and bus bar can be integrally covered with insulating resin after being connected, which significantly simplifies the structure and manufacturing process compared to conventional methods, and also improves the uniformity of the insulating resin film thickness.

[0059] As shown in Figures 12(A) and 12(B), the coil 11 and bus bar 13 may be bonded together and then coated with insulating resin in a substantially flat plate state (before bending the coil 11). However, if the coil 11 is bent after being coated with insulating resin, the insulating resin will stretch around the bend, reducing the coating thickness and potentially resulting in a deterioration in withstand voltage. Therefore, as shown in Figure 12(C), by coating the coil 11 and bus bar 13 together with insulating resin in a bent state, the uniformity of the insulating resin film thickness can be improved, and a deterioration in withstand voltage can be avoided.

[0060] A neutral point connection terminal 15 is attached to the other end 11B of each coil 11 by, for example, welding. The neutral point connection terminal 15 is provided so as to be located outside (lead out from) the spiral structure of each coil 11. Furthermore, the external terminal 13C of the bus bar 13 is bent into a desired shape.

[0061] 13A and 13B are plan views of the coil units 10V and 10W. The coil units 10V and 10W are manufactured in the same manner. That is, as shown in FIG. 13A, the bus bar 13V of the coil unit 10V is punched to have the wiring portion 13AV, the coil connection end 13BV, and the external terminal 13CV, and the coil connection end 13BV and the bus bar connection end 11AV of the coil 11 are connected in the same manner as described above (FIG. 13B).

[0062] As shown in FIG. 13(C), the bus bar 13W of the coil unit 10W is punched to have a wiring portion 13AW, a coil connection end 13BW, and an external terminal 13CW, and the coil connection end 13BW and the bus bar connection end 11AW of the coil 11 are connected in the same manner as described above (FIG. 13(D)).

[0063] However, the positions of these three coil connection ends 13BV, 13BW are shifted from the positions of the three coil connection ends 13BU of coil unit 10U, and the positions of external terminals 13CV, 13CW are shifted from the position of external terminal 13CU of coil unit 10U, so that they do not interfere with each other when the three coil units 10U, 10V, 10W are combined.

[0064] Thereafter, coils 11 of coil units 10V and 10W are also bent relative to bus bar 13 so that the first central axis C1 of each coil 11 intersects with the direction of the second central axis C2 of bus bar 13. As a result, the direction of second central axis C2 of bus bar 13 and the direction of the long side of one-turn region CR of coil 11 are aligned in the same direction, and coil units 10V (see FIG. 6) and 10W (see FIG. 7) are formed in which wiring portion 13A of bus bar 13 is located above coil 11 (above the upper short side of one-turn region CR). <Method for manufacturing stator member> The stator member 20 is formed by combining the coil units 10U, 10V, and 10W manufactured using the above method (and coated with insulating resin). As shown in FIG. 4, the three coil units 10U, 10V, and 10W are combined so that they are positioned adjacent to each other at equal intervals (120°) and so that the current or voltage phases are different from each other. The bus bars 13U, 13V, and 13W of the three coil units 10U, 10V, and 10W are stacked so that the central axes of their wiring portions 13AU, 13AV, and 13AW are aligned. As mentioned above, the coil connection terminals 13BU, 13BV, and 13BW of the three coil units 10U, 10V, and 10W are offset from each other, and the external terminals 13CU, 13CV, and 13CW are also offset from each other. This prevents interference between the coils 11 and the external terminals 13CU, 13CV, and 13CW when the coils are combined.

[0065] Thereafter, the neutral point connection terminals 15 of the three coil units 10U, 10V, and 10W are connected to the neutral point, and the stator member 20 is formed.

[0066] Alternatively, the coil units 10U (FIG. 12(A)), 10V (FIG. 13(B)), and 10W (FIG. 13(D)) may each be coated with insulating resin in the form of a substantially flat plate, and stacked so that the central axes of the wiring portions 13AU, 13AV, and 13AW of the bus bars 13U, 13V, and 13W are aligned, and then the coils 11 connected to the bus bars 13U, 13V, and 13W may be bent. <Method for manufacturing stator and motor> A manufacturing method of the stator 35 will be described with reference to Fig. 14. The stator 35 has, for example, a cylindrical stator core 351, a plurality of cassettes 352, and the above-mentioned stator members 20. The stator members 20 of this embodiment are attached to the stator core 351 afterward.

[0067] For example, as shown in FIG. 1A, a pair of cassettes 352 are prepared for each of the multiple coils 11 (one for each coil 11) constituting the stator member 20. Each pair of cassettes 352 (352A, 352B) has flanges 352C and 352D on one side and the other side of the axial center of the spiral structure of the coil 11. One coil 11 is inserted into one cassette 352A from the side where flange 352C is not formed, and the other cassette 352B is placed on top of it from the side where flange 352D is not formed, engaging the two and attaching the cassette 352 to the coil 11. Cassettes 352 are similarly attached to all of the coils 11 constituting the stator member 20, and the coils 11 with the cassettes 352 attached are attached to the stator core 351 as shown in FIG. 1B and FIG. 1C, thereby constructing the stator 35.

[0068] As shown in FIG. 8(C), the rotor 33 is rotatably assembled to the stator 35, thereby manufacturing the three-phase motor 30.

[0069] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. [Industrial Applicability]

[0070] The present invention can be applied to a stator and a motor. [Explanation of symbols]

[0071] 10, 10U, 10V, 10W coil unit 11, 11U, 11V, 11W coil 11A, 11AU, 11AV, 11AW Busbar connection end 11B Other end 11S end face 13, 13U, 13V, 13W busbar 13AU wiring section 13A,13AU,13AV,13AW wiring section 13B, 13BU, 13BV, 13BW Coil connection end 13C, 13CU, 13CV, 13CW external terminal 13S end face 15 Neutral point connection terminal 20 Stator member 30 Three-phase motor 31 Shaft 32 Housing 33 Rotor 34 bearings 35 Stator 100 Bonding equipment (cold pressure welding equipment) 101 Holding part 101D Lower holding body 101U upper holding body 102 Holding part 102D Lower holding body 102U upper holding body 111 Flat conductor 111S end face 351 stator core 352 cassettes

Claims

1. A coil unit in which a coil and a bus bar are joined, the bus bar is integrally formed with a wiring portion and a connection portion connected to an end of the coil by a conductor having a first surface, the connecting portion and the end portion are joined by joining end surfaces together, the first surface of the bus bar is positioned on approximately the same plane from the connection portion to the entire wiring portion, the second surface in the joining region between the connection portion and the end portion and the third surface at the end portion are positioned on approximately the same plane as the first surface, and the coil and the bus bar are joined together in a state in which the first surface and an area of ​​one circumference of the coil are each approximately parallel to each other; A coil unit characterized by:

2. The joining region is provided midway around the coil.

2. The coil unit according to claim 1.

3. The joining region, the connection portion, and the coil are integrally covered with an insulating resin.

2. The coil unit according to claim 1.

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