Stator, electric motor, and method of manufacturing stator

Abstract

To prevent deformation of a terminal caused by tension of jumper wires that connect adjacent coils.SOLUTION: A stator 2 comprises: an annular stator core 10 having a plurality of teeth 12; coils 30 each wound around each of the teeth 12; jumper wires 31 for connecting the adjacent coils 30; and terminals 42 electrically connected to the jumper wires 31. The plurality of coils 30 and jumper wires 31 are formed with one coil wire. Tension relaxation mechanisms 51 are provided that come into contact with areas other than contact portions P1 in contact with the terminals 42 of the jumper wires 31 to bend the jumper wires.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a stator for an electric motor. [Background technology]

[0002] For example, in the electric motor shown in Patent Document 1 below, a coil wire is wound in a concentrated manner around each tooth of a stator core to form a plurality of coils separately, and then the ends of adjacent coils are connected to form a jumper wire connecting these coils. Then, a terminal (U-shaped hook) provided on a busbar unit is brought into contact with the jumper wire between the coils, and these are connected by fusing (thermal crimping). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-151093 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, when a plurality of coils are separately formed, ends of adjacent coils are connected to form a jumper wire, and then a terminal is brought into contact with the jumper wire, the number of steps is large.

[0005] In contrast, if adjacent coils are formed from a single coil wire, the number of steps can be reduced. Specifically, after forming one of the coils C1, as shown in Fig. 11, the coil wire (crossover wire 101) drawn from the coil C1 is hooked to a terminal 102, and then the next coil C2 is formed. In this way, by continuously forming adjacent coils C1 and C2 from a single coil wire and hooking the crossover wire 101 connecting these coils C1 and C2 to the terminal 102, the number of steps can be reduced compared to when these are performed in separate processes.

[0006] However, when the coil wire is hooked onto the terminal in the coil winding process as described above, tension of the coil wire is applied to the terminal, which may cause deformation of the terminal.

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to prevent deformation of terminals due to tension in crossover wires connecting adjacent coils. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a stator including an annular stator core having a plurality of teeth, coils wound around each of the teeth, jumper wires connecting adjacent coils, and terminals electrically connected to the jumper wires, the adjacent coils and the jumper wires connecting them being formed from a single coil wire, The present invention provides a stator provided with a tension relief mechanism that contacts and bends the crossover wire in an area other than the contact portion with the terminal.

[0009] In the above stator, tension is applied to the area of ​​the crossover wire between the contact portion with the terminal and the bent portion by the tension relief mechanism. In this case, the tension of the crossover wire is applied not only to the terminal but also to the tension relief mechanism, so the load applied to the terminal is reduced and deformation of the terminal can be prevented.

[0010] In the above stator, the terminal and the tension relief mechanism are provided at approximately the same axial position, and the region P3 of the crossover wire between the contact portion P1 with the terminal and the bend P2 caused by the tension relief mechanism can be made to extend in a direction perpendicular to the axial direction (see FIG. 7). This makes it difficult for tension from the crossover wire to be applied to the terminal, making it possible to more reliably prevent deformation of the terminal.

[0011] Furthermore, the above-mentioned terminal may be disposed at an axial position farther from the coil than the tension relief mechanism (see FIG. 9). In this case, it becomes easier to prevent a jig (e.g., a fusing jig) for clamping the terminal and electrically connecting the terminal to the jumper wire from interfering with the tension relief mechanism, facilitating the above-mentioned connection work.

[0012] The tension relief mechanism may have a pair of tension relief parts provided on both circumferential sides of the contact part between the crossover wire and the terminal. In this case, the axial positions of the bent part of the crossover wire caused by the pair of tension relief parts may be made different (see FIG. 10). In particular, when the pair of tension relief parts has an upstream tension relief part that contacts an area of ​​the crossover wire that is upstream of the contact part with the terminal and a downstream tension relief part that contacts an area of ​​the crossover wire that is downstream of the contact part with the terminal, it is preferable to arrange the bent part of the crossover wire caused by the upstream tension relief part at an axial position closer to the coil than the bent part of the crossover wire caused by the downstream tension relief part.

[0013] The tension relief mechanism may have a drop-out prevention part that engages with the crossover wire in a direction perpendicular to the axial direction (for example, in the radial direction). In this case, the crossover wire that comes into contact with the tension relief mechanism is locked by the drop-out prevention part, thereby preventing the crossover wire from coming off the tension relief mechanism.

[0014] In the above stator, the crossover wires are provided between adjacent coils, so that the crossover wires are unlikely to come into contact with each other. Therefore, the crossover wires do not need to be routed to the outer diameter side to avoid interference with other crossover wires, so the crossover wires can be arranged on the inner diameter side. For example, when the stator core has a cylindrical portion connecting the outer diameter ends of multiple teeth, at least a part of the contact portion between the crossover wire and the terminal can be arranged on the inner diameter side of the inner circumferential surface of the cylindrical portion.

[0015] The crossover wire may be disposed at a circumferential position closer to the downstream coil than the center of a circumferential region between the plurality of coils.

[0016] In the above stator, all of the coils may be formed from a single coil wire, and the terminal and the tension relieving portion may be provided on all of the crossover wires connecting adjacent coils.

[0017] The above-mentioned stator can be manufactured by carrying out the steps of forming one of the coils, forming a jumper wire by hooking the coil wire drawn from the coil to a terminal and a tension relief mechanism while applying tension, and forming the next coil with the coil wire extending downstream of the jumper wire. Effect of the Invention

[0018] As described above, according to the present invention, it is possible to prevent deformation of the terminal due to tension of the crossover wire. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a plan view of the electric motor as viewed from the axial direction. [Diagram 2] FIG. 2 is a perspective view of a stator of the electric motor. [Diagram 3] FIG. 2 is a cross-sectional view taken along line ZZ in FIG. [Figure 4] 5A and 5B are diagrams showing a connection state between the coils and terminal members of the stator. [Diagram 5] FIG. 4 is a perspective view of a terminal member of the stator. [Figure 6] FIG. 2 is a perspective view of the stator near a terminal. [Figure 7] FIG. 4 is a view of the vicinity of the terminal of the stator as viewed from the inner diameter side. [Figure 8] FIG. 2 is an enlarged view of FIG. [Figure 9] 13 is a view showing the vicinity of a terminal of a stator according to another embodiment as viewed from the inner diameter side. FIG. [Figure 10] 13 is a view showing the vicinity of a terminal of a stator according to still another embodiment as viewed from the inner diameter side. FIG. [Figure 11]FIG. 11 is a perspective view of the vicinity of a terminal of a stator according to a reference example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] The electric motor 1 shown in FIG. 1 is a three-phase DC brushless motor, and mainly includes a stator 2 according to an embodiment of the present invention and a rotor 3. The stator 2 has a stator core 10, an insulator 20, a coil 30, and a terminal unit 40 (see FIGS. 2 and 3). The rotor 3 has a rotor core and a plurality of magnets fixed to the rotor core. The rotor 3 rotates by controlling a current supplied from an external power source by an inverter circuit and supplying it to the coil 30 of the stator 2. In the following description, the axial direction of the stator 2 is referred to as the "axial direction", and the circumferential direction and radial direction centered on the axis are referred to as the "circumferential direction" and the "radial direction". In addition, in the axial direction, the side where the terminal unit 40 is arranged with respect to the stator core 10 (the upper side in FIG. 2) is referred to as the "upper side", and the opposite side (the lower side in FIG. 2) is referred to as the "lower side", but this is not intended to limit the usage mode of the electric motor 1.

[0022] As shown in Fig. 2, the stator core 10 integrally includes a cylindrical portion 11 and a plurality of teeth 12 protruding from the cylindrical portion 11 inwardly. The stator core 10 is integrally formed, for example, from laminated steel sheets made of a laminate of electromagnetic steel sheets with an insulating coating, or from a powder core made of a compact of soft magnetic powder with an insulating coating. The teeth 12 are arranged at a plurality of locations (12 locations in the illustrated example) that are equally spaced in the circumferential direction. The number of parallel coils 30 is the number of grooves (the number of teeth 12) / 3, which is 4 in this embodiment.

[0023] 3, the insulator 20 is a resin part that is disposed between the stator core 10 and the coil 30 to insulate them from each other. The insulator 20 has a cylindrical shape that fits onto the outer circumferential surfaces of the teeth 12.

[0024] The coil 30 is made of a coil wire wound in a concentrated manner around the outer periphery of each tooth 12 of the stator core 10. Specifically, the coil 30 is disposed on the outer periphery of the insulator 20 attached to each tooth 12. The coil wire is made of a conductive wire (e.g., a copper wire) covered with an insulating material such as enamel.

[0025] In the stator 3, adjacent coils 30 and the jumper wire 31 connecting them are formed from a single coil wire. In this embodiment, all coils 30 are formed from a single continuous coil wire, and both ends of this coil wire are connected to each other (see FIG. 4). As a result, a connection part 31a between the ends of the coil wire is formed in one of the jumper wires 31 (the jumper wire 31 at the right end in FIG. 4). The other jumper wires 31 are made of a single coil wire without a connection part, and are continuous with the coil wires of the coils 30 provided on both sides. The white circles in FIG. 4 are the connection parts 31a between the ends of the coil wires, and are also the connection parts between the jumper wire 31 and the terminal member 41 described later. On the other hand, the black circles in FIG. 4 are the connection parts between the jumper wire 31 and the terminal member 41, and no connection parts between the ends of the coil wires are provided.

[0026] The terminal unit 40 has a first terminal member 41(A), a second terminal member 41(B), a third terminal member 41(C), and a resin part 50 (see Figs. 2 and 3). The terminal member 41 is made of a conductive material, for example, a metal (copper or brass). The resin part 50 is annular and holds the first terminal member 41(A), the second terminal member 41(B), and the third terminal member 41(C). In this embodiment, the resin part 50 and the terminal members 41(A), 41(B), and 41(C) are integrally formed by injection molding of resin using the terminal members 41(A), 41(B), and 41(C) as insert parts.

[0027] As shown in Fig. 5, each terminal member 41 integrally has a plurality of terminals 42 and an annular portion 43 that connects the plurality of terminals 42. In this embodiment, each terminal member 41 has four terminals 42 that are provided at equal intervals in the circumferential direction. In the illustrated example, the terminals 42 are formed of U-shaped hooks that open upward. The crossover wire 31 is disposed inside the U-shaped terminals 42 (see Fig. 6) and is electrically connected to the terminals 42.

[0028] In this embodiment, the coils 30 are connected in a delta connection. Specifically, as shown in Fig. 4, the first terminal member 41(A) is connected to the crossover wire 31 connecting the V-phase coil 30 and the U-phase coil 30, the second terminal member 41(B) is connected to the crossover wire 31 connecting the W-phase coil 30 and the V-phase coil 30, and the third terminal member 41(C) is connected to the crossover wire 31 connecting the U-phase coil 30 and the W-phase coil 30. A power supply line from an external power source is connected to each terminal member 41.

[0029] The resin part 50 integrally includes a plurality of tension relief mechanisms 51 provided for each terminal 42, and an annular holding part 52 that holds the annular parts 43 of the first to third terminal members 41 insulated from each other (see Figs. 2 and 3). The tension relief mechanisms 51 of this embodiment have a pair of tension relief parts 53 provided on both circumferential sides of each terminal 42 (see Fig. 6). In the illustrated example, a pair of tension relief parts 53 is provided on both circumferential sides of all of the terminals 42.

[0030] Each tension relief portion 53 is in contact with the crossover wire 31. More specifically, as shown in Fig. 7, the tension relief portion 53 is in contact with an area of ​​the crossover wire 31 other than the contact portion P1 with the terminal 42. A bent portion P2 formed by the tension relief portion 53 is provided in the crossover wire 31. A tension is applied to an area P3 of the crossover wire 31 between the contact portion P1 with the terminal 42 and the bent portion P2 formed by the tension relief portion 53 due to the elastic force of the coil wire.

[0031] The stator 2 is formed in the following procedure. First, the insulator 20 is attached to the outer periphery of each tooth 12 of the stator core 10, and the terminal unit 40 is attached to the upper side of the stator core 10. Then, the coil 30 is formed by winding the coil wire while applying tension to the outer periphery of each tooth 12 using an automatic coil winding device (not shown). In this embodiment, the coil 30 is formed by winding the coil wire in a clockwise direction around the outer periphery of the tooth 12 shown at the right end of FIG. 4, and then the coil 30 is formed by winding the coil wire in the clockwise direction around the outer periphery of the adjacent (left) tooth 12. At this time, the coil wire drawn out from the previously formed coil 30 is hooked to the terminal 42 and the tension relaxation mechanism 51 (a pair of tension relaxation parts 53) as shown in FIG. 7, and then the next coil 30 is formed. The arrows in FIG. 7 indicate the order in which the coil wire is hooked to the terminal 42, etc., and the right side of the jumper wire 31 in the figure is the upstream side, and the left side of the figure is the downstream side.

[0032] In this manner, in the process of winding the coil wire to form the coil 30, the tension of the coil wire is applied to the coil 30 by hooking the crossover wire 31 between the coils 30 to the terminal 42. In this embodiment, the tension of the crossover wire 31 is applied not only to the terminal 42 but also to the tension relief portion 53 provided near the terminal 42, so that the load applied to the terminal 42 is reduced. In this embodiment, as shown in FIG. 7, the axial position of the upper surface 53a of the tension relief portion 53 is substantially the same as the axial position of the support surface 42a of the terminal 42 that supports the crossover wire 31 from below. In addition, in the illustrated example, the region of the crossover wire 31 between the bent portions P2 formed by the pair of tension relief portions 53 extends linearly along a direction perpendicular to the axial direction (the left-right direction in FIG. 7). As a result, substantially all of the tension applied to the region of the crossover wire 31 between the pair of bent portions P2 is applied to the pair of tension relief portions 53, and almost no load is applied to the terminal 42, so that deformation of the terminal 42 can be reliably prevented.

[0033] The above steps are repeated to continuously form all the coils 30 from a single coil wire, and then both ends of the coil wire are connected (see connection portion 31a in FIG. 4). Then, each terminal 42 and each jumper wire 31 are electrically connected. This connection is performed, for example, by fusing. Specifically, while the terminal 42 is clamped from both radial sides by a jig 60 (shown by a chain line in FIG. 7), a current is passed through the terminal 42 and the jumper wire 31 via the jig 60. This causes heat to be generated at the contact portion between the terminal 42 and the jumper wire 31, removing the insulating coating of the jumper wire 31, and fusing the jumper wire 31 and the terminal 42 to electrically connect them.

[0034] In this embodiment, after all the coils 30 are formed from a single coil wire as described above, both ends of the coil wire are clamped by one terminal 42 and fused together. This allows the connection of both ends of the coil wire and the connection of the connection parts 31a (see FIG. 4) to the terminal 42 to be performed simultaneously. In this case, tension is not applied to the jumper wire 31 having the connection parts 31a at both ends of the coil wire, so the tension relief mechanism 51 that contacts the jumper wire 31 may be omitted. In the illustrated example, in order to facilitate manufacturing, the tension relief mechanism 51 is provided at a portion that contacts all the jumper wires 31. The jumper wires 31 and the terminals 42 can also be connected by welding (laser welding or TIG welding). In this case, however, it is necessary to remove the insulating coating of the jumper wire 31 before welding.

[0035] In this embodiment, since each coil 30 is wound by concentrated winding, the winding start 32 of each coil 30 is disposed on the inner circumference of the coil 30, and the winding end 33 of each coil 30 is disposed on the outer circumference of the coil 30 (see FIG. 2). In this case, the jumper wire 31 connected to the winding end 33 of the upstream coil 30 and the winding start 32 of the downstream coil 30 is disposed in a circumferential position closer to the downstream coil 30 (left side in the figure) than the center part Q of the circumferential region between the adjacent coils 30, as shown in FIG. 8. The terminal 42 and tension relief mechanism 51 in contact with the jumper wire 31 are also disposed in a circumferential position closer to the downstream coil 30 than the center part Q of the circumferential region between the adjacent coils 30.

[0036] As described above, adjacent coils 30 are connected by the jumper wires 31, so that all of the jumper wires 31 are provided in different circumferential regions (see FIG. 1). In particular, in this embodiment, all of the coils 30 are wound in the same direction (see FIG. 4), so that all of the jumper wires 31 are arranged at equal intervals in the circumferential direction, ensuring circumferential intervals between the jumper wires 31 (see FIG. 1). In this case, the jumper wires 31 do not come into contact with each other, so there is no need to take measures to avoid insulation between the jumper wires 31, and design and manufacturing are simplified.

[0037] The tension relief mechanism 51 is provided with a falling-off prevention portion that prevents the crossover wire 31 from falling off. In this embodiment, as shown in Fig. 3 and Fig. 6, a protruding portion 54 that protrudes upward from the inner diameter end of the tension relief portion 53 functions as the falling-off prevention portion. The protruding portion 54 engages with the crossover wire 31 hooked on the upper surface 53a of the tension relief portion 53 from the inner diameter side, thereby preventing the crossover wire 31 from falling off to the inner diameter side.

[0038] The present invention is not limited to the above embodiment. Other embodiments of the present invention will be described below, but redundant description of points similar to the above embodiment will be omitted.

[0039] The jig 60 used to fuse the terminal 42 and the crossover wire 31 must be disposed above the tension relief mechanism 51 in order to avoid interference with the tension relief mechanism 51 (see FIG. 7). When the terminal 42 and the tension relief mechanism 51 are disposed so as to overlap partially in the axial direction as in the above embodiment, if the jig 60 is disposed above the tension relief mechanism 51, the jig 60 will not be able to clamp the entire terminal 42, which may cause an impediment to the fusing operation.

[0040] 9, the terminal 42 is disposed above the tension relief mechanism 51 (i.e., at an axial position farther from the coil 30). This makes it possible to clamp the entire terminal 42 with the jig 60 even if the jig 60 is disposed above the tension relief mechanism 51, making the fusing operation easier.

[0041] 10, the axial positions of the upper surfaces 53a of a pair of tension relief portions 53 provided on both sides of the terminal 42 are made different, thereby making the axial positions of the bent portion P2 formed by the pair of tension relief portions 53 in the crossover wire 31 different. In the illustrated example, of the pair of tension relief portions 53, the bent portion P2(B) formed by the upstream tension relief portion 53(B) provided on the upstream side (right side in the figure) is disposed lower (i.e., at an axial position closer to the coil 30) than the bent portion P2(A) formed by the downstream tension relief portion 53(A) provided on the downstream side (left side in the figure).

[0042] By arranging the bent portion P2(A) by the downstream tension relief portion 53(A) at approximately the same axial position as the contact portion P1 between the crossover wire 31 and the terminal 42, the tension of the crossover wire 31 is easily applied to this tension relief portion 53, and the load applied to the terminal 42 is reduced. In addition, by arranging the bent portion P3(B) by the upstream tension relief portion 53(B) below the terminal 42, a space for arranging a fusing jig 60 can be secured above this upstream tension relief portion 53(B). As a result, it is possible to facilitate the fusing operation while preventing deformation of the terminal 42.

[0043] The electric motor 1 as described above is incorporated in, for example, an electric oil pump provided in a vehicle with an idling stop function or a hybrid vehicle. [Explanation of symbols]

[0044] 1 Electric motor 2 Stator 3 Rotor 10 Stator core 11 Cylindrical part 12 Teeth 20 Insulator 30 Coil 31 Crossover 40 Terminal Unit 41 Terminal parts Terminal 42 43 Circular section 50 Holding part 51 Tension relief mechanism 52 Holding part 53 Tension relief 54 Protrusion 60 Jig P1 Contact point between crossover and terminal P2 Bending part of crossover wire with tension relief mechanism

Claims

1. A stator including an annular stator core having a plurality of teeth, coils wound around each of the teeth, jumper wires connecting adjacent coils, and terminals electrically connected to the jumper wires, the adjacent coils and the jumper wires connecting them being formed from a single coil wire, a stator provided with a tension relief mechanism that contacts and bends the crossover wire in an area other than the contact portion with the terminal;

2. 2. The stator according to claim 1, wherein tension is applied to a region of the crossover wire between a contact portion with the terminal and a bent portion formed by the tension relaxation mechanism.

3. 2. The stator according to claim 1, wherein a region of the crossover wire between a contact portion with the terminal and a bent portion formed by the tension relief mechanism extends along a direction perpendicular to the axial direction.

4. The stator according to claim 1 , wherein the terminal is disposed at an axial position farther from the coil than the tension relief mechanism.

5. 2. The stator according to claim 1, wherein the tension relief mechanism includes a pair of tension relief portions provided on both circumferential sides of a contact portion between the crossover wire and the terminal.

6. The stator according to claim 5 , wherein the axial positions of the bent portions of the crossover wires formed by the pair of tension relieving portions are different from each other.

7. the tension relief mechanism has an upstream tension relief portion that contacts an area of ​​the crossover wire that is upstream of a contact portion with the terminal, and a downstream tension relief portion that contacts an area of ​​the crossover wire that is downstream of a contact portion with the terminal, 7. The stator according to claim 6, wherein a bent portion of the crossover wire caused by the upstream tension relief portion is disposed at an axial position closer to the coil than a bent portion of the crossover wire caused by the downstream tension relief portion.

8. 2. The stator according to claim 1, wherein the tension relief mechanism has a dropout prevention portion that engages with the crossover wire in a direction perpendicular to the axial direction.

9. the stator core has a cylindrical portion connecting outer diameter ends of the plurality of teeth, The stator according to claim 1 , wherein at least a part of a contact portion between the crossover wire and the terminal is disposed radially inward relative to an inner circumferential surface of the cylindrical portion.

10. 2. The stator according to claim 1, wherein the crossover wire is disposed at a circumferential position closer to the downstream coil than a center of a circumferential region between the plurality of coils.

11. All the coils are formed from the single coil wire, 2. The stator according to claim 1, wherein the terminal and the tension relaxation portion are provided on all of the crossover wires connecting adjacent coils.

12. An electric motor comprising: the stator according to claim 1; and a rotor disposed on the inner periphery of the stator.

13. A method for manufacturing a stator comprising: an annular stator core having a plurality of teeth; coils wound around each of the teeth; jumper wires connecting adjacent coils; and terminals electrically connected to the jumper wires, the adjacent coils and the jumper wires connecting them being formed from a single coil wire, forming any one of the coils; a step of hooking the coil wire drawn out from the coil around the terminal and a tension relief mechanism to form the jumper wire; and forming a next coil from the coil wire extending downstream of the jumper wire.

Images