Manufacturing method of stator for rotating electric machine and stator for rotating electric machine

Abstract

To form an adhesive fixing part joined to a bus bar member and a coil end by using a structure other than a bridge.SOLUTION: A stator for a rotary electric machine is disclosed, comprising: a stator core; a stator coil in which two or more sets of multiple phases are connected in parallel at a neutral point; a joining part that joins an end of a conductor part of the bus bar member and an end of the stator coil to each other; and an adhesive fixing part that is joined to the bus bar member and a coil end. The conductor part includes a neutral line bus bar forming the neutral point. The bus bar member has a through hole penetrating the insulating material part and the neutral line bus bar in an axial direction. The through hole overlaps the coil end when seen in the axial direction, and has the adhesive fixing part extending therein.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a stator for a rotating electric machine and a stator for a rotating electric machine. [Background technology]

[0002] To increase the bonding strength between the busbar member and the coil end, a known technique is to use a high-viscosity varnish to form adhesive fastening portions that join the busbar member and the coil end. In this case, a bridge (beam portion) is provided at the radial end of the busbar member, and an adhesive fastening portion is formed that encloses the bridge and joins the coil end, thereby increasing the bonding strength between the busbar member and the coil end. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-114116 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described conventional technology increases the bonding strength between the busbar member and the coil end by providing adhesive fixing portions in areas of the busbar member, in which multiple busbars are integrated with an insulating material portion, that do not overlap the busbars in an axial direction (areas where a bridge can be formed). However, when attempting to reduce the size of the busbar member or increase the density of the arrangement of multiple busbars, the areas that do not overlap the busbars in an axial direction are limited, making it difficult to secure locations for forming adhesive fixing portions.

[0005] Therefore, in one aspect, an object of the present disclosure is to make it possible to form adhesive fixing portions that join bus bar members and coil ends by using a structure other than a bridge. [Means for solving the problem]

[0006] In one aspect, a stator core; a stator coil in which two or more sets of multiple phases are connected in parallel at a neutral point, the stator coil being attached to the stator core and having coil ends at both axial ends; a bus bar member that is disposed axially outward of the coil end on one axial end side, the bus bar member having a conductor portion and an insulating material portion integrated together, and an end of the conductor portion exposed from the insulating material portion; a joint portion that joins an end of the conductor portion of the bus bar member to an end of the stator coil; adhesive fixing portions that are joined to the bus bar members and the coil ends, the conductor portion includes a neutral bus bar that forms the neutral point, the bus bar member has a through hole that passes through the insulating material portion in the axial direction and is closed in a direction intersecting the axial direction, The through-hole overlaps with the coil end when viewed in the axial direction, and the adhesive fixing portion extends inside the through-hole. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, it is possible to form adhesive fixing portions that join the bus bar members and the coil ends by using a structure other than a bridge. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 2 is a perspective view showing a part of a stator. [Figure 1B] FIG. 2 is a perspective view showing a part of the stator with the bus bar members removed. [Figure 2] FIG. 1 is a perspective view showing only the four concentric coils in an assembled state. [Figure 3] FIG. 2 is a perspective view showing a single concentric coil. [Figure 4A] FIG. [Figure 4B] FIG. 10 is a perspective view showing a molding portion according to another example. [Figure 5] FIG. 3 is a side view showing a schematic perspective view of the inside of the molding section. [Figure 6] FIG. 2 is a schematic plan view of the bus bar member of the present embodiment as viewed in the axial direction. [Figure 7] 7 is a schematic plan view showing in perspective the inside of the bus bar member shown in FIG. 6. FIG. [Figure 7A] FIG. 2 is a schematic plan view of a neutral bus bar in a single unit state as viewed in the axial direction. [Figure 8] FIG. 2 is an explanatory diagram of an example of a wiring pattern of a stator coil. [Figure 9] FIG. 7 is a schematic cross-sectional view taken along line AA in FIG. 6 according to the first embodiment. [Figure 10] FIG. 10 is an explanatory diagram of a comparative example. [Figure 11] FIG. 10 is a schematic cross-sectional view of a bus bar member according to a second embodiment. [Figure 12A] FIG. 4 is a perspective view showing a dam portion around a through hole from the outside in the axial direction. [Figure 12B] FIG. 10 is yet another perspective view showing the dam portion around the through hole from the outside in the axial direction. [Figure 13] 12C shows the same view as FIG. 12B but at a different axial position in cross section. [Figure 14] 12C shows the same view as FIG. 12B but at a different axial position in cross section. [Figure 15] 12C shows the same view as FIG. 12B but at a different axial position in cross section. [Figure 16] 10 is a flowchart illustrating a general flow of a method for manufacturing a stator. [Figure 17] FIG. 2 is an explanatory diagram showing the initial state of a high-viscosity varnish injected in an injection process. [Figure 18] FIG. 1 is an explanatory diagram showing the state of the high-viscosity varnish at an intermediate stage (part 1) after being poured in the pouring step. [Figure 19] FIG. 10 is an explanatory diagram showing the state of the high-viscosity varnish injected in the injection step at an intermediate stage (part 2). [Figure 20] FIG. 2 is an explanatory diagram showing the final stage of the high-viscosity varnish injected in the injection process. [Figure 21] FIG. 10 is a cross-sectional view showing the configuration of a neutral bus bar around a through hole according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Furthermore, shapes and the like in the drawings may be partially exaggerated for the sake of explanation. Note that in Figure 1A and other figures, for ease of viewing, only some of the reference symbols may be assigned to multiple parts with the same attribute.

[0010] FIG. 1A is a perspective view showing a portion of the stator 21. FIG. 1B is a perspective view showing a portion of the stator 21 with the busbar members 70 removed. FIG. 2 is a perspective view showing only the four concentric wound coils 20 in an assembled state. FIG. 3 is a perspective view showing a single concentric wound coil 20. In FIG. 1A, the Y direction corresponds to the radial direction, the Y1 side corresponds to the radially outer side, and the Y2 side corresponds to the radially inner side (the side closer to the central axis I of the stator 21). In FIGS. 1A and 1B, a formed portion 60 of the busbar members 70, which will be described later, is omitted from the illustration.

[0011] In the following description, the axial direction refers to the direction in which the central axis I of the stator 21 (see FIG. 9, etc.) extends, and the radial direction refers to the radial direction centered on the central axis I. Therefore, the radially outer side refers to the side away from the central axis I, and the radially inner side refers to the side toward the central axis I. Furthermore, the axially outer side refers to the side away from the axial center of the stator 21, and the axially inner side refers to the side approaching the axial center of the stator 21. Furthermore, the circumferential direction corresponds to the direction of rotation around the central axis I.

[0012] The stator 21 includes a stator core 211 made of, for example, annular laminated steel plates of a magnetic material, and a plurality of slots 2111 are formed radially inside the stator core 211, around which the stator coils 22 are wound. The plurality of slots 2111 are formed at equal intervals in the circumferential direction. The number and shape of the slots 2111 are arbitrary.

[0013] The stator coil 22 is, for example, in the form of a so-called concentric coil 20 as shown in Figures 2 and 3, and is a cassette coil formed by bending a rectangular wire wound a predetermined number of times. The stator coil 22 includes a rectangular wire having a rectangular cross section (specifically, a rectangular shape). This rectangular wire may be made of a highly conductive metal such as copper or aluminum. The stator coil 22 may be made of a rectangular wire covered with an insulating coating.

[0014] In the example shown in Figure 2, four concentric wound coils 20 spaced circumferentially by 90 degrees are connected to each other in such a manner that the second jumper wire 240 of one concentric wound coil 20 is joined to the third jumper wire 250 of another concentric wound coil 20 adjacent to that one concentric wound coil 20.

[0015] Each of the concentric coils 20 is a cassette coil wound with a predetermined number of turns. Note that the predetermined number of turns is arbitrary, and may be a greater number of turns as shown in Figures 1A and 1B.

[0016] As shown in Fig. 3, each concentric wound coil 20 has slot-accommodated portions 230, 232, first crossover wires 234, 236, a second crossover wire 240, and a third crossover wire 250. The slot-accommodated portions 230, 232 and the first crossover wires 234, 236 form a main body portion (a substantially hexagonal closed loop portion) of the concentric wound coil 20. The first crossover wire 236, together with the second crossover wire 240 and the third crossover wire 250, form a coil end on one axial side (the lead side), and the first crossover wire 234 forms a coil end on one axial side (the anti-lead side). In the example shown in Fig. 3, one concentric wound coil 20 includes multiple slot-accommodated portions 230, 232 and multiple first crossover wires 234, 236, but only one second crossover wire 240 and one third crossover wire 250.

[0017] The slot-accommodated portions 230 and 232 are each inserted (accommodated) in the slot 2111 of the stator core 211 and extend in a substantially linear manner so as to axially penetrate the slot 2111. In the same concentrically wound coil 20, the slot-accommodated portion 230 and the slot-accommodated portion 232 are accommodated in different slots 2111 that are spaced a predetermined distance apart in the circumferential direction of the stator core 211.

[0018] The first crossover wires 234 and 236 are connected to the slot-accommodated portions 230 and 232, respectively, and are portions that protrude axially outward from the axial end face of the stator core 211 and connect two circumferentially separated slot-accommodated portions 230 and 232. The first crossover wire 236 includes an apex portion 2361 and inclined portions 2362 and 2363. The same is true for the first crossover wire 234, but no reference numerals are used here.

[0019] The second crossover wire 240 and the third crossover wire 250 connect the slot-accommodated portions 230, 232 of two concentric wound coils 20 that are spaced apart in the circumferential direction.

[0020] 3, the second crossover wire 240 may be formed through a plurality of bending processes. Specifically, the second crossover wire 240 includes a first oblique portion 2402, a first edgewise bent portion 2404, a first straight portion 2406, a first flatwise bent portion 2408, a second straight portion 2410, a second edgewise bent portion 2412, a third straight portion 2414, a third edgewise bent portion 2416, and a fourth straight portion 2418. The first oblique portion 2402 is formed from an end portion 2302 of the slot-received portion 230. The end portion 2302 of the slot-received portion 230 is formed by edgewise bending a portion extending axially outward of the slot-received portion 230 toward the circumferentially outer side (the side away from the center between the slot-received portions 230, 232 in the circumferential direction).

[0021] 3, the third connecting wire 250 may be formed through a plurality of bending processes. Specifically, the third connecting wire 250 includes a second oblique portion 2502, a fourth edgewise bent portion 2504, a fifth straight portion 2506, a second flatwise bent portion 2508, and a sixth straight portion 2510. The second oblique portion 2502 is formed from an end portion 2322 of the slot-received portion 232. The end portion 2322 of the slot-received portion 232 is formed by edgewise bending a portion extending axially outward of the slot-received portion 232 toward the circumferentially outer side (the side away from the center between the slot-received portions 230, 232 in the circumferential direction).

[0022] Although a specific configuration of the concentric wound coil 20 has been described here, the detailed configuration of the concentric wound coil 20 is arbitrary. For example, the shapes of the second crossover wire 240 and the third crossover wire 250 are arbitrary.

[0023] Furthermore, among the concentric wound coils 20, the concentric wound coil 20 that is joined to the bus bar member 70, which will be described later, may have a configuration slightly different from that shown in Fig. 3 (Fig. 2). For example, the second crossover wire 240 may have a configuration in which the portion from the first flatwise bent portion 2408 to the third edgewise bent portion 2416 is not bent.

[0024] Furthermore, coil pieces having a different shape from the concentrically wound coil such as the concentrically wound coil 20 (for example, U-shaped coil pieces) may form the stator coil 22. Hereinafter, the stator coil 22 is assumed to have a configuration in which a rectangular wire is covered with an insulating coating, and unless otherwise specified, "one coil conductor 22a" refers to any one of the multiple coil conductors that form the stator coil 22.

[0025] As described above (see also FIG. 1A), the multiple coil conductors 22a are housed in the slots 2111 of the stator core 211, and end portions extending axially outward from the slots 2111 are joined together. In the concentric wound coil 20 shown in FIGS. 2 and 3, the slot-accommodated portions 230, 232 are housed in the slots 2111 of the stator core 211, and end portions of the second crossover wire 240 and the third crossover wire 250 extending axially outward from the slots 2111 (end portions of the fourth straight portion 2418 and the sixth straight portion 2510) are joined together. The joining of the end portions of the coil conductors 22a may be achieved by welding or the like. In this case, the end portions of the coil conductors 22a may be overlapped with at least a portion of the coating removed (i.e., with the conductor end portion 22A (see FIG. 5 described later) exposed), and the removed portions may be joined together by welding. In this case, welding may be performed by any method such as laser welding or TIG welding. Hereinafter, the two ends of the coil conductor 22a that are overlapped and joined in this manner will also be referred to as "joint 402."

[0026] The multiple coil conductors 22a may have a molded portion 60 made of a molding material at the joint 402. The molded portion 60 covers the entire joint 402 of the multiple coil conductors 22a. The molded portion 60 has the function of ensuring electrical insulation of the joint 402 of the multiple coil conductors 22a. That is, since the coating is removed from the joint 402 of the multiple coil conductors 22a when they are joined as described above, the molded portion 60 covers the entire area from which the coating has been removed, thereby fulfilling the same function as a coating. The molded portion 60 may be formed by injection molding of a resin material.

[0027] FIG. 4A is an explanatory diagram of a formed portion 60. In FIG. 4A, the X direction corresponds to the circumferential direction. FIG. 4B is an explanatory diagram of a formed portion 60A of another embodiment. In FIG. 4B, the Z direction represents a direction parallel to the axial direction, as in FIG. 1A, and the Z1 side corresponds to the axially outer side of the coil end shown in FIG. 4B. FIG. 5 is a side view showing a schematic perspective view of the interior of the formed portion 60.

[0028] One molding section 60 is provided for each two circumferentially adjacent pairs of joints 402. In Fig. 4A, one molding section 60 is provided for each two circumferentially adjacent pairs of joints 402, but one molding section 60 may be provided for each pair of joints 402, or one molding section 60 may be provided for each of three or more circumferentially adjacent pairs of joints 402. In Fig. 4A, the molding section 60 is molded by clamping in the vertical direction, but it may also be formed by clamping in the radial direction, as in molding section 60A shown in Fig. 4B.

[0029] 1A again, a bus bar member 70 is disposed on the lead-side coil end. The bus bar member 70 is firmly joined (fixed) to the coil end, as will be described in detail below.

[0030] Hereinafter, the fixing structure of the bus bar member 70 and the coil end of this embodiment will be described in detail with reference to FIG. 6 and subsequent figures.

[0031] FIG. 6 is a schematic plan view of the busbar member 70 of this embodiment as viewed in the axial direction. FIG. 7 is a schematic plan view showing the interior of the busbar member 70 shown in FIG. 6 in a see-through manner. FIG. 7A is a schematic plan view of the neutral busbar 74N alone as viewed in the axial direction. FIG. 8 is an explanatory diagram of an example of a wiring mode of the stator coil 22. FIG. 9 is a schematic cross-sectional view taken along line AA in FIG. 6 according to this embodiment. Note that FIG. 7A also schematically illustrates a portion of a through-hole 78 (the portion that penetrates the neutral busbar 74N), which will be described later.

[0032] The busbar member 70 has busbars 74U, 74V, 74W, and 74N integrated with an insulating material portion 90, and the busbars 74U, 74V, 74W, and 74N extend radially from the insulating material portion 90. The insulating material portion 90 is formed, for example, from a resin material. In this case, the busbar member 70 may be formed by insert molding. The busbar member 70 has a through-hole 78 penetrating in the axial direction. The through-hole 78 penetrates the insulating material portion 90 and a portion of the busbar (in this embodiment, the neutral busbar 74N). The shape of the through-hole 78 when viewed in the axial direction is arbitrary, and may be a circle as shown in FIG. 6, a polygon, or another shape.

[0033] Bus bars 74U, 74V, and 74W are bus bars associated with the U phase, V phase, and W phase, respectively. Bus bar 74N is a neutral bus bar. Bus bars 74U, 74V, 74W, and 74N may each be formed from a single piece of bus bar (sheet metal member).

[0034] In this embodiment, bus bars 74U, 74V, 74W, and 74N have a structure corresponding to the Y-connection of stator coil 22 as shown in Fig. 8. Specifically, stator coil 22 has two or more sets of U-phase, V-phase, and W-phase connected in parallel. In the example shown in Fig. 8, stator coil 22 has a so-called 2Y-connection configuration in which there are two Y-connection sets.

[0035] In this embodiment, although the stator coil 22 has a structure corresponding to a 2Y connection (described later with reference to FIG. 8), the neutral bus bar 74N is formed as a one-piece bus bar. Specifically, as shown in FIG. 7A, the neutral bus bar 74N is formed as a one-piece bus bar in which two sets of neutral points N1 and N2 (see FIG. 8) are connected via a connection portion 740N. Note that in FIG. 7, a portion 741 of the neutral bus bar 74N connected to one circumferential end of the connection portion 740N forms a Y connection for a first set of three phases (see U(1), V(1), and W(1) in FIG. 7A), and a portion 742 connected to the other circumferential end of the connection portion 740N forms a Y connection for a second set of three phases (see U(2), V(2), and W(2) in FIG. 7A). This allows for an efficient structure with fewer parts than when the portion 741 and the portion 742 are formed as separate pieces.

[0036] As shown in FIG. 7, the busbars 74U, 74V, 74W, and 74N are preferably arranged to overlap each other in the axial direction while being offset from each other by a necessary insulation distance. This allows the busbar member 70 to be reduced in size in the circumferential and radial directions. In this embodiment, as an example, the busbars 74U, 74V, and 74W are arranged to overlap the neutral busbar 74N in the axial direction radially outward of their respective external terminals 71 (see FIG. 1A and FIG. 9 described later) (hereinafter, also referred to as a "two-story structure"). In this specification, the phrase "overlapping" two elements in a specific direction includes a concept in which one element partially overlaps the other in the specific direction and a concept in which one element encompasses the other in the specific direction.

[0037] Each of the bus bars 74U, 74V, 74W, and 74N has a radially inner end portion 80 that is exposed from the insulating material portion 90 and extends radially inward. The radially inner end portions 80 of the bus bars 74U, 74V, 74W, and 74N may be exposed from the insulating material portion 90 in a circumferentially aligned manner. Each of the radially inner end portions 80 is joined to an end portion (conductor end portion 22A) of the coil conductor wire 22a. The joining between the radially inner end portion 80 and the end portion of the coil conductor wire 22a may be achieved by a method similar to the method for joining the ends of the coil conductor wire 22a described above. Furthermore, a shaped portion 60A similar to the shaped portion 60A shown in FIG. 4B (see FIG. 9, etc., described later) may be formed at a joint 402 between the radially inner end portion 80 and the end portion of the coil conductor wire 22a.

[0038] Each of the bus bars 74U, 74V, 74W, and 74N has a radially outer end portion 81 that is exposed from the insulating material portion 90 and extends radially outward. The radially outer end portions 81 may be exposed from the insulating material portion 90 in a circumferentially aligned manner. Each of the radially outer end portions 81 is joined to an end portion (conductor end portion 22A) of the coil conductor 22a (see FIG. 5). The joining between the radially outer end portion 81 and the end portion of the coil conductor 22a may be achieved by a method similar to the method for joining the ends of the coil conductor 22a described above. Furthermore, a shaped portion 60 similar to the shaped portion 60 shown in FIG. 4A (see FIG. 9, etc., described later) may be formed at a joint 402 between the radially outer end portion 81 and the end portion of the coil conductor 22a.

[0039] In this embodiment, due to the two-story structure described above, the radially inner end portions 80 of the bus bars 74U, 74V, 74W, and 74N are exposed from the insulating material portion 90 at approximately the same axial position, while the radially outer end portions 81 are exposed from the insulating material portion 90 at different axial positions. In this case, the radially outer end portions 81 have different axial lengths after exposure, and therefore may be bent radially outward at the same axial position.

[0040] Each of the bus bars 74U, 74V, and 74W has an external terminal 71 that is exposed from the insulating material portion 90 and extends outward in the axial direction. The external terminal 71 forms a power line terminal that is electrically connected to a power source (not shown) via an inverter (not shown).

[0041] 9, in this embodiment, hardened adhesive portions 50, 51 (hereinafter referred to as "adhesive fixing portions 50, 51") are provided between the first crossover wire 236 and the bus bar member 70 in the axial direction. The adhesive fixing portions 50, 51 are provided between the first crossover wire 236 and the bus bar member 70 in the axial direction, and bond (bond by adhesion) the first crossover wire 236 and the bus bar member 70.

[0042] The adhesive fixing portions 50, 51 are formed using an adhesive. Any adhesive may be used, but a high-viscosity varnish is preferred. Here, the high-viscosity varnish is, for example, a varnish having a viscosity of greater than 200 Pa·s, preferably a varnish having a viscosity of 300 Pa·s or greater. In this case, the adhesive fixing portions 51 can be formed so as to extend into the through-holes 78, etc., in the axial direction corresponding to the direction of gravity during manufacturing, as described below. When the slots 2111 are filled with varnish (not shown), a low-viscosity varnish having a viscosity of 80 to 200 Pa·s may be used. The high-viscosity varnish may be formed using a polyimide resin, a polyester resin, an epoxy resin, or the like. A preferred method for forming the adhesive fixing portions 50, 51 (particularly the adhesive fixing portion 51) will be described later.

[0043] The adhesive fixing portions 50, 51 extend in the axial direction between the first crossover wire 236 and the busbar member 70, and by joining the first crossover wire 236 and the busbar member 70, have the function of eliminating or reducing vibrations that may occur between the first crossover wire 236 and the busbar member 70 (hereinafter referred to as the "vibration reduction function").

[0044] The adhesive fixing portion 50 is joined to the coil end while enveloping the bridge 500 as disclosed in the above-mentioned Patent Document 1. The bridge 500 may be formed between the radially inner end portions 80 in the circumferential direction. A plurality of adhesive fixing portions 50 may be formed along the circumferential direction (see FIG. 6).

[0045] The adhesive fixing portion 51 includes a portion 511 extending into the through hole 78 and a portion 512 extending from the through hole 78 to the coil end. The portions 511 and 512 are integral. As shown in Fig. 9 , the portion 512 may be joined to the axially outer surface of the coil end, and also to a surface 910 of the insulating material portion 90 that faces the coil end (the surface around the through hole 78).

[0046] In this embodiment, the through-hole 78 in which the adhesive fixing portion 51 is provided penetrates the insulating material portion 90 and the neutral bus bar 74N, as shown in Figures 6, 7, and 9. The through-hole 78 is formed in a radial position overlapping the coil end when viewed in the axial direction so that the lower end (axial end) of the adhesive fixing portion 51 is joined to the coil end. In this embodiment, the through-hole 78 is formed radially outward of the external terminal 71. In this way, according to this embodiment, by using the neutral bus bar 74N, the adhesive fixing portion 51 can be formed radially outward of the external terminal 71.

[0047] Here, through holes that penetrate the busbar, such as through hole 78, locally reduce the cross-sectional area of the busbar. That is, the cross-sectional area of the busbar is locally reduced at the location where the through hole is formed. Such a reduction in the cross-sectional area reduces the upper limit of the current (upper limit of the amount of electricity) that can flow through the busbar to the stator coil 22. That is, it reduces the electrical characteristics of the busbar member 70.

[0048] To prevent such a decrease in the upper limit of the current, the through-hole 78 is preferably formed in the connection portion 740N of the neutral busbar 74N. As described above, the connection portion 740N is a portion that makes the neutral busbar 74N a one-piece unit, and does not substantially form a current path. Therefore, in this case, the through-hole 78 can be formed without degrading the electrical characteristics of the busbar member 70. That is, according to this embodiment, by using the connection portion 740N of the neutral busbar 74N, the adhesive fixing portion 51 can be formed without degrading the electrical characteristics of the busbar member 70.

[0049] In particular, in a vehicle environment, a rotating electric machine including the stator 21 is susceptible to vibration due to input from the road surface or, in the case of a vehicle equipped with an internal combustion engine, input from the internal combustion engine. In particular, the busbar members 70 have a significantly larger mass than the second crossover wire 240 and are therefore more susceptible to vibration. Vibration of the busbar members 70 may reduce the reliability of the joints 402 (see joints 402 in FIG. 5 ) between the radially inner end 80 and the radially outer end 81 of the busbar members 70 and the ends of the coil conductor 22a.

[0050] In this regard, according to this embodiment, as described above, adhesive fixing portions 50, 51 are provided between the first crossover wire 236 and the bus bar member 70 in the axial direction, and the vibration reduction function of the adhesive fixing portions 50, 51 reduces stress concentration at or near the edge of the joint 402, thereby improving the reliability of the joint 402 between the bus bars 74U, 74V, 74W, 74N of the bus bar member 70 and the end of the coil conductor 22a.

[0051] The adhesive fixing portions 50, 51 are preferably arranged relatively uniformly over the entire circumferential length of the busbar member 70 so that the vibration reduction function can be exhibited relatively uniformly over the entire busbar member 70. Similarly, the adhesive fixing portions 50, 51 are preferably arranged relatively uniformly over the entire radial length of the busbar member 70 so that the vibration reduction function can be exhibited relatively uniformly over the entire radial length of the busbar member 70.

[0052] In this regard, in this embodiment, the adhesive fixing portion 50 can be uniformly arranged along the circumferential direction by utilizing an area on the radially inner side that does not overlap with the busbars 74U, 74V, 74W, and 74N when viewed in the axial direction (an area where the bridge 500 can be formed). Furthermore, the adhesive fixing portion 51 is provided corresponding to the connection portion 740N of the neutral busbar 74N, and can therefore be arranged near the center in the circumferential direction. This allows the vibration reduction function to be exhibited relatively uniformly throughout the entire busbar member 70.

[0053] Furthermore, in this embodiment, the adhesive fixing portion 50 is formed on the radially inner side, while the adhesive fixing portion 51 is formed on the radially outer side. This allows the vibration-reducing function to be exerted throughout the entire radial length of the busbar member 70. For example, in a comparative busbar member 70′ as shown in FIG. 10 , which includes only the adhesive fixing portion 50 of the adhesive fixing portions 50 and 51, the insulating material portion 90′ does not include the adhesive fixing portion 51. Therefore, as shown by the arrow R11, the radially outer side is likely to vibrate in the axial direction with the radially inner side as a fulcrum. When such vibration occurs, relatively high stress is likely to be generated, particularly at the joint 402 (see joint 402 in FIG. 5 ) between the radially outer end portion 81 and the end of the coil conductive wire 22a. In contrast, in this embodiment, the adhesive fixing portions (adhesive fixing portions 50 and 51) are provided on both the radially inner and outer sides as described above, thereby preventing the disadvantages that occur in the comparative example.

[0054] Here, since the adhesive fixing portion 50 forms a bridge 500 with an axial through-hole 501, it can only be formed in an area (the radial end of the bus bar member 70) that does not overlap with the bus bars 74U, 74V, 74W, and 74N as viewed in the axial direction. Furthermore, in this embodiment, due to the two-story structure radially outward of the external terminal 71 described above (i.e., due to the presence of the neutral conductor bus bar 74N), it is difficult to form a bridge similar to the bridge 500 with an axial through-hole 501 radially outward of the external terminal 71. In this regard, in this embodiment, the adhesive fixing portion 51 can be provided radially outward of the external terminal 71 by utilizing the through-hole 78 of the neutral conductor bus bar 74N as described above.

[0055] As described above with reference to Figures 6 to 8, this embodiment is applied to bus bars 74U, 74V, and 74W having a 2Y connection structure. However, as will be explained in more detail in the following Example 2, it is also applicable to other parallel connection structures such as a 4Y connection.

[0056] Next, a preferred embodiment having a dam portion 79 around a through hole 78 will be described with reference to Figures 11 to 15. For the sake of distinction, the embodiment described above will also be referred to as "Embodiment 1" below, and the embodiment described below with reference to Figures 11 to 15 will also be referred to as "Embodiment 2." Below, the configuration of Embodiment 2, which may be similar to that of Embodiment 1 above, may be assigned the same reference numerals, and description thereof may be omitted.

[0057] FIG. 11 is a schematic cross-sectional view of a busbar member 70A according to a second embodiment, taken along line AA in FIG. 6. FIGS. 12A to 15 are views partially illustrating dam portions 79 around through holes 78. FIG. 12A is a perspective view illustrating the dam portions 79 around through holes 78 from the axially outer side. FIG. 12B is a perspective view enlarged from FIG. 12A and viewed from a different direction than FIG. 12A, illustrating the dam portions 79 around through holes 78 from the axially outer side. FIGS. 13 to 15 are views of the same cross-section as FIG. 12B but at different axial positions. Note that, for convenience of illustration, busbars 74U, 74V, and 74W in FIGS. 12A to 15 have a 4Y-connection structure, which differs from the 2Y-connection structure shown in FIGS. 6 to 8, etc. In the case of a 4Y connection structure, the neutral bus bar 74N may be connected to another 2Y portion via a connection portion 740N (see FIG. 7A).

[0058] The bus bar member 70A according to the second embodiment differs from the bus bar member 70 according to the first embodiment in that the insulating material portion 90 is replaced with an insulating material portion 90A. The insulating material portion 90A differs from the insulating material portion 90 according to the first embodiment (see FIG. 9 ) in that it has a dam portion 79 around the through hole 78.

[0059] The dam portion 79 surrounds an opening 780 at the axially outer end of the through hole 78. The dam portion 79 may have any height, but for example, as shown in Fig. 12A , it may protrude axially outward from the axially outer base surface 701A of the busbar member 70A by the same height as the portion surrounding the external terminal 71. In this case, the opening 780 at the axially outer end of the through hole 78 may be formed in the base surface 701A.

[0060] The weir portion 79 forms a hollow portion 790 having a cross-sectional shape larger than that of the opening portion 780. The cross-sectional shape here refers to the cross-sectional shape when cut along a plane perpendicular to the axial direction, and the same applies hereinafter. FIGS. 13 to 15 show the relationship between the cross-sectional shape of the through hole 78 and the cross-sectional shape of the hollow portion 790. FIG. 13 shows the cross-sectional shape at an axial position passing through the hollow portion 790, FIG. 14 shows the cross-sectional shape at an axial position passing through the neutral bus bar 74N, and FIG. 15 shows the cross-sectional shape at an axial position closer to the coil end than the neutral bus bar 74N (an axial position passing through the insulating material portion 90A). In this modification, as shown in FIGS. 14 and 15 , the cross-sectional shape of the through hole 78 is substantially the same at each axial position, but may have a tapered surface such as a tapered surface 792 of the weir portion 79, which will be described later.

[0061] The dam portion 79 preferably has a cross-sectional shape of the cavity 790 that gradually increases in size as it extends axially outward. That is, the dam portion 79 has a tapered surface 792 that widens as it extends axially away from the coil end. This allows the high-viscosity varnish to be efficiently guided to the opening 780, even when a high-viscosity varnish with relatively low fluidity is used.

[0062] The same effects as those of the above-described Example 1 can be obtained with Example 2. Furthermore, according to Example 2, by providing the dam portion 79 as described above, it is possible to efficiently form the adhesive fixing portion 51A that reaches the coil end via the through hole 78, even when a high-viscosity varnish with a relatively low fluidity is used. The effects in this regard will be further described in relation to the explanation of the manufacturing method below.

[0063] Next, a manufacturing method suitable for manufacturing the above-described stator 21 will be described with reference to FIG. 16 and subsequent figures.

[0064] In the following description, unless otherwise specified, the first crossover wire 236 refers to the entirety (collection) of the above-mentioned multiple first crossover wires 236 on the lead side that extend circumferentially on the axial outside of the stator core 211. Therefore, the surface (axial outer surface) of the first crossover wire 236 refers to the entire surface (axial outer surface) of the multiple first crossover wires 236, and represents the collection of each surface (axial outer surface) of the first crossover wires 236.

[0065] Fig. 16 is a flowchart that schematically shows the flow of a method for manufacturing stator 21. Fig. 17 to Fig. 20 are explanatory diagrams of some of the steps that will be described with reference to Fig. 16. Note that the flowchart in Fig. 16 merely shows one example of the flow of a method for manufacturing stator 21, and the processing order of the steps may be changed as appropriate, or the steps may be performed in parallel or simultaneously.

[0066] This manufacturing method first includes, in step S111, preparing the stator core 211, a coil assembly, and the bus bar member 70A. The coil assembly may be an assembly in which a plurality of concentrically wound coils 20 are arranged in a circular ring shape. In a modified example, coil pieces of any shape different from the concentrically wound coils 20 may be used.

[0067] In this manufacturing method, the bus bar member 70A is prepared, but the method can also be applied to the bus bar member 70 in substantially the same manner.

[0068] Next, in step S113, the manufacturing method includes a process (mounting process) of assembling the coil assembly to the stator core 211. This process may be achieved, for example, by using a jig such as an inserter to insert the slot accommodating portions 230, 232 that form the coil assembly into the slots 2111 of the stator core 211. This results in the formation of a stator assembly in which the stator coil 22 is wound around the stator core 211 and which has coil ends on both axial sides.

[0069] Next, in step S114, the manufacturing method includes a step (arrangement step) of placing the busbar member 70A on the lead-side coil end of the stator assembly. In this case, the busbar member 70A may be placed in contact with the axially outer surface of the coil end (i.e., the surface of the first crossover wire 236).

[0070] Next, in step S115, the manufacturing method includes a step (joining step) of joining by welding ends of the second crossover wire 240 and the third crossover wire 250, which are a pair of crossover wires that overlap in the axial direction, in a circumferential range where no busbar member 70A is arranged in the multiple concentric wound coils 20 wound around the stator core 211. Also, in step S115, the manufacturing method includes a step (joining step) of joining by welding each end of the second crossover wire 240 and the third crossover wire 250 to each radially inner end 80 and each radially outer end 81 of the busbars 74U, 74V, 74W, 74N of the busbar member 70A in a circumferential range where the busbar member 70A is arranged.

[0071] The manufacturing method also includes, in step S116, a step of forming a molded portion 60 (see FIG. 4A) at a joint (not shown) between the second crossover wire 240 and the third crossover wire 250 in a circumferential range where the busbar member 70A is not arranged. The manufacturing method also includes, in step S116, a step of forming the molded portions 60, 60A at each joint 402 between each end of the second crossover wire 240 and the third crossover wire 250 and each of the radially inner end portions 80 and each of the radially outer end portions 81 of the busbar members 70A, 74U, 74V, 74W, and 74N, in a circumferential range where the busbar member 70A is arranged.

[0072] Next, as schematically shown in FIG. 17 , this manufacturing method includes an injection process in step S117 in which high-viscosity varnish (not shown) is injected into the bus bar member 70A with the side on which the bus bar member 70A is arranged facing up (see arrow R17 in FIG. 17 ) to form the adhesive fixing portion 51A. The injection of the high-viscosity varnish may be achieved by dripping using a nozzle. Alternatively, the high-viscosity varnish may be injected by being pressure-fed and sprayed. The injection of the high-viscosity varnish may be performed in an amount sufficient to accumulate in the cavity 790 (for example, an amount just before overflowing). FIGS. 18 to 20 are diagrams schematically showing the movement of the injected high-viscosity varnish 5 (high-viscosity varnish 5 for the adhesive fixing portion 51A). The high-viscosity varnish 5 flows downward due to its own weight, but because it has relatively low fluidity, it flows downward at a relatively slow speed (see arrow R18 in FIG. 18 and arrow R19 in FIG. 19). When it reaches the coil end, it spreads laterally (see arrow R20 in FIG. 20), ensuring the necessary joining area with the coil end.

[0073] When using high-viscosity varnish, the fluidity of the varnish is relatively low, so it takes a relatively long time from the start of injection of the high-viscosity varnish until the required joining area between the coil end and the varnish is secured. Therefore, when using the busbar member 70 (see FIG. 9) instead of the busbar member 70A, the busbar member 70 does not have a cavity 790 defined by the dam portion 79, so injection of the high-viscosity varnish must be performed intermittently for a relatively long time. In contrast, the busbar member 70A has a cavity 790 defined by the dam portion 79, so the injection process can be completed by injecting the required amount of high-viscosity varnish into the cavity 790. In other words, the volume of the cavity 790 may be adjusted depending on the required amount of high-viscosity varnish injected. This can efficiently improve productivity. Therefore, for example, after injecting the required amount of high-viscosity varnish into the hollow portion 790, it may be possible to start or finish the injection process of high-viscosity varnish for the adhesive fixing portion 50 before the high-viscosity varnish reaches the coil end as shown in Figure 20.

[0074] Next, in step S119, the manufacturing method includes a step of hardening the high-viscosity varnish. Note that the high-viscosity varnish may be hardened together with the varnish that may be retained (impregnated) between the coil conductive wires 22a that constitute the concentric wound coil 20.

[0075] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0076] For example, in the above-described embodiment, the adhesive fixing part 50 is provided in addition to the adhesive fixing parts 51 and 51A as a preferred embodiment, but the adhesive fixing part 50 may be omitted.

[0077] Furthermore, in the above-described embodiment, a two-story structure is formed in which bus bars 74U, 74V, and 74W overlap neutral bus bar 74N radially outward from external terminal 71, but a structure in which the radial inside and outside are reversed may also be realized. That is, a two-story structure may be realized in which bus bars 74U, 74V, and 74W overlap neutral bus bar 74N radially inward from external terminal 71. In this case, through holes 78 and, accordingly, adhesive fixing portions 51 (similarly to adhesive fixing portion 51A) may be similarly formed radially inward from external terminal 71.

[0078] 14 and 15 , in the above-described embodiment, the cross-sectional shape of the through hole 78 in the insulating material portion 90 is the same as the cross-sectional shape of the through hole 78 in the bus bar member 70, but this is not limited to this. That is, the cross-sectional shape of the through hole 78 in the insulating material portion 90 may be different from the cross-sectional shape of the through hole 78 in the neutral bus bar 74N.

[0079] Furthermore, in the above-described embodiment, the through hole 78 passes through the neutral bus bar 74N. However, this is not limited to this. For example, a modified example as shown in FIG. 21 is also possible. FIG. 21 is a cross-sectional view showing the configuration of the neutral bus bar 74N around the through hole 78C according to a modified example, taken at the same axial position as FIG. 14 . As shown in FIG. 21 , the neutral bus bar 74N may be adjacent to the through hole 78C in a manner slightly offset radially inward from the through hole 78C. In this case, as shown in FIG. 21 , the neutral bus bar 74N may have a connection portion 740N in the form of a notch, and the through hole 78 may be disposed at a position adjacent to the connection portion 740N from the radial outside. Note that in the modified example shown in FIG. 21 , the neutral bus bar 74N is adjacent to the through hole 78 in a manner slightly offset radially inward from the through hole 78C. However, the neutral bus bar 74N may be adjacent to the through hole 78 without such an offset. In this way, the through-hole 78 need only pass through the insulating material portion 90 in the axial direction and be closed in a direction intersecting the axial direction, and does not need to pass through the neutral bus bar 74N. However, passing the neutral bus bar 74N through the through-hole 78 is advantageous in that it makes it easier to make the width (radial width) of the connection portion 740N relatively wide.

[0080] Furthermore, in the above-described embodiment, the through-hole 78 extends linearly in the axial direction, but it may also extend in the axial direction in a slightly curved manner. [Explanation of symbols]

[0081] 21 stator (stator for rotating electric machine), 211 stator core, 22 stator coil, 51 adhesive fixing portion, 70 busbar member, 71 external terminal (power line terminal), 74U, 74V, 74W busbar (conductor portion), 74N neutral busbar (conductor portion), 740N connection portion, 78 through hole, 780 opening, 79 weir portion, 792 tapered surface, 80 radially inner end (end of conductor portion), 81 radially outer end (end of conductor portion), 90, 90A insulating material portion

Claims

1. A stator core; a stator coil in which two or more sets of multiple phases are connected in parallel at the neutral point of each set, the stator coil being attached to the stator core and having coil ends at both axial ends; a bus bar member that is disposed axially outward of the coil end on one axial end side, the bus bar member having a conductor portion and an insulating material portion integrated together, and an end of the conductor portion exposed from the insulating material portion; a joint portion that joins an end of the conductor portion of the bus bar member to an end of the stator coil; an adhesive fixing portion formed by an adhesive that is bonded to the bus bar member and the coil end, the conductor portion includes a neutral bus bar that forms the neutral point, the busbar member has a through hole between two or more of the neutral points, the through hole passing through the insulating material portion in the axial direction and being closed in a direction intersecting the axial direction, The through hole overlaps with the coil end when viewed in the axial direction, and the adhesive fixing portion extends inside the through hole.

2. the neutral conductor busbar is in the form of a single piece integrally including current path portions that form the current paths of the multiple phases in a manner that forms two or more of the neutral points, and connection portions that connect the current path portions, The stator for a rotating electric machine according to claim 1 , wherein the through hole passes through the connection portion of the neutral bus bar or is adjacent to the connection portion in the radial direction.

3. the through hole has an axial opening on a side of the insulating material portion farther from the coil end, 2. The stator for a rotating electric machine according to claim 1, wherein the insulating material portion has a dam portion surrounding the opening.

4. The stator for a rotating electric machine according to claim 3 , wherein the dam portion has a tapered surface that widens as it extends away from the coil end in the axial direction.

5. the conductor portion includes a plurality of bus bars, the plurality of bus bars include power line terminals electrically connected to a power source; At least two of the plurality of bus bars overlap each other on one radial side of the power line terminal as viewed in the axial direction, The stator for a rotating electric machine according to claim 1 , wherein the through hole is formed on one side in the radial direction relative to the power line terminal.

6. 2. The stator for a rotating electric machine according to claim 1, wherein the adhesive fixing portion is formed of a varnish having a viscosity of more than 200 Pa·s.

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