WO2024262251A1 - Stator, electric motor, and method for manufacturing stator - Google Patents

Abstract

A stator 2 includes: an annular stator core 10 having a plurality of teeth 12; a coil 30 wound around each tooth 12; a crossover wire 31 connecting adjacent coils 30; and a terminal 42 electrically connected to the crossover wire 31. The plurality of the coils 30 and the crossover wire 31 are formed of one coil wire. The crossover wire 31 is provided with a tension relaxation mechanism 51 that is bent in contact with a region other than a contact part P1 with the terminal 42.

Description

Stator, electric motor, and method for manufacturing a stator

The present invention relates to a stator for an electric motor.

For example, in the electric motor shown in Patent Document 1 below, coil wire is wound in a concentrated manner around each tooth of a stator core to form multiple coils separately, and then the ends of adjacent coils are connected to form jumper wires that connect these coils. After that, terminals (U-shaped hooks) provided on the busbar unit are brought into contact with the jumper wires between the coils, and these are connected by fusing (thermal crimping).

JP 2021-151093 A

As described above, if multiple coils are formed separately, the ends of adjacent coils are connected to form a jumper, and then the terminal is brought into contact with the jumper, the labor required increases.

In contrast, if adjacent coils are formed with a single coil wire, the amount of labor can be reduced. Specifically, after forming one of the coils C1, as shown in FIG. 11, the coil wire (crossover wire 101) pulled out from that coil C1 is hooked onto a terminal 102, and then the next coil C2 is formed. In this way, by continuously forming adjacent coils C1 and C2 with a single coil wire and hooking the crossover wire 101 connecting these coils C1 and C2 onto a terminal 102, the amount of labor can be reduced compared to performing these processes in separate steps.

However, if the coil wire is hooked onto the terminal during the coil winding process as described above, tension will be applied to the terminal, which may cause the terminal to deform.

The present invention aims to prevent terminal deformation caused by tension in the jumper wires connecting adjacent coils.

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.

In the above stator, tension is applied to the area of the crossover wire between the contact point with the terminal and the bent part caused 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.

In the above stator, the terminal and the tension relief mechanism are located at approximately the same axial position, and the area P3 of the jumper wire between the contact point 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 Figure 7). This makes it difficult for tension from the jumper wire to be applied to the terminal, making it possible to more reliably prevent deformation of the terminal.

Furthermore, in the above-mentioned terminal, the 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 avoid a situation where a jig (e.g., a fusing jig) for clamping the terminal and electrically connecting the terminal to the jumper wire interferes with the tension relief mechanism, making the above-mentioned connection work easier.

The tension relief mechanism may have a pair of tension relief parts provided on both circumferential sides of the contact part between the jumper wire and the terminal. In this case, the axial position of the bent part of the jumper 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 the area of the jumper wire that is upstream of the contact part with the terminal, and a downstream tension relief part that contacts the area of the jumper wire that is downstream of the contact part with the terminal, it is preferable to arrange the bent part of the jumper wire caused by the upstream tension relief part in an axial position closer to the coil than the bent part of the jumper wire caused by the downstream tension relief part.

The tension relief mechanism can have a drop prevention part that engages with the jumper wire in a direction perpendicular to the axial direction (e.g., the radial direction). In this case, the jumper wire that comes into contact with the tension relief mechanism is locked by the drop prevention part, thereby preventing the jumper wire from coming off the tension relief mechanism.

In the above stator, the jumper wires are provided between adjacent coils, making it difficult for the jumper wires to come into contact with each other. Therefore, there is no need to route the jumper wire around to the outer diameter side to avoid interference with other jumper wires, and the jumper wire can be arranged on the inner diameter side. For example, if 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 jumper wire and the terminal can be arranged on the inner diameter side of the inner circumferential surface of the cylindrical portion.

The jumper wire may be positioned circumferentially closer to the downstream coil than the center of the circumferential region between the multiple coils.

In the above stator, all coils can be formed from a single coil wire, and the terminal and tension relief portion can be provided on all jumper wires connecting adjacent coils.

The above 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 that coil to a terminal and a tension relief mechanism while applying tension, and forming the next coil with the coil wire that extends downstream of the jumper wire.

As described above, the present invention makes it possible to prevent deformation of the terminal due to tension in the crossover wire.

FIG. 2 is a plan view of the electric motor as viewed from the axial direction. FIG. 2 is a perspective view of a stator of the electric motor. 2 is a cross-sectional view taken along line Z-Z in FIG. 1. 5A and 5B are diagrams showing a connection state between the coils and terminal members of the stator. FIG. 4 is a perspective view of a terminal member of the stator. FIG. 2 is a perspective view of the stator near a terminal. FIG. 4 is a view of the vicinity of the terminal of the stator as viewed from the inner diameter side. FIG. 2 is an enlarged view of FIG. 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. 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. FIG. 11 is a perspective view of the vicinity of a terminal of a stator according to a reference example.

The following describes an embodiment of the present invention with reference to the drawings.

The electric motor 1 shown in FIG. 1 is a three-phase DC brushless motor, and mainly includes a stator 2 according to one 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 number of magnets fixed to the rotor core. The rotor 3 rotates by controlling the 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 (upper side in FIG. 2) is referred to as the "upper side", and the opposite side (lower side in FIG. 2) is referred to as the "lower side", but this is not intended to limit the manner of use of the electric motor 1.

As shown in FIG. 2, the stator core 10 has an integral cylindrical portion 11 and a number of teeth 12 protruding inward from the cylindrical portion 11. The stator core 10 is formed integrally, 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 multiple locations (12 locations in the illustrated example) at equal intervals 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.

As shown in FIG. 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 is cylindrical and fits onto the outer circumferential surface of the teeth 12.

The coil 30 is made of 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 arranged on the outer periphery of the insulator 20 attached to each tooth 12. The coil wire is made of a conductor (e.g., copper wire) coated with an insulating material such as enamel.

In the stator 3, adjacent coils 30 and the jumper wires 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 portion 31a between the ends of the coil wire is formed on one of the jumper wires 31 (the jumper wire 31 at the right end of FIG. 4). The other jumper wires 31 are made of a single coil wire without a connection portion, and are continuous with the coil wires of the coils 30 provided on both sides. The white circles in FIG. 4 are the connection portions 31a between the ends of the coil wires, and are also the connection portions between the jumper wires 31 and the terminal members 41 described below. On the other hand, the black circles in FIG. 4 are the connection portions between the jumper wires 31 and the terminal members 41, and no connection portions between the ends of the coil wires are provided.

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 with the terminal members 41(A), 41(B), and 41(C) as insert parts.

As shown in FIG. 5, each terminal member 41 integrally has multiple terminals 42 and an annular portion 43 that connects the multiple terminals 42. In this embodiment, each terminal member 41 has four terminals 42 that are arranged at equal intervals in the circumferential direction. In the illustrated example, the terminals 42 consist of U-shaped hooks that open upward. The jumper wire 31 is arranged inside the U-shaped terminals 42 (see FIG. 6) and is electrically connected to the terminals 42.

In this embodiment, each coil 30 is connected in a delta connection. Specifically, as shown in FIG. 4, a first terminal member 41 (A) is connected to a jumper wire 31 that connects the V-phase coil 30 and the U-phase coil 30, a second terminal member 41 (B) is connected to a jumper wire 31 that connects the W-phase coil 30 and the V-phase coil 30, and a third terminal member 41 (C) is connected to a jumper wire 31 that connects 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.

The resin part 50 integrally includes a plurality of tension relief mechanisms 51 provided for each terminal 42, and an annular retaining portion 52 that holds the annular portions 43 of the first to third terminal members 41 insulated from each other (see Figures 2 and 3). The tension relief mechanism 51 of this embodiment has a pair of tension relief portions 53 provided on both circumferential sides of each terminal 42 (see Figure 6). In the illustrated example, a pair of tension relief portions 53 is provided on both circumferential sides of all terminals 42.

Each tension relief portion 53 is in contact with the jumper wire 31. More specifically, as shown in FIG. 7, the tension relief portion 53 is in contact with the jumper wire 31 in an area other than the contact portion P1 with the terminal 42. The jumper wire 31 is provided with a bent portion P2 formed by the tension relief portion 53. In the jumper wire 31, a region P3 between the contact portion P1 with the terminal 42 and the bent portion P2 formed by the tension relief portion 53 is subjected to tension due to the elastic force of the coil wire.

The stator 2 is formed in the following manner. First, an insulator 20 is attached to the outer periphery of each tooth 12 of the stator core 10, and a terminal unit 40 is attached to the upper side of the stator core 10. Then, an automatic coil winding device (not shown) winds the coil wire while applying tension to the outer periphery of each tooth 12 to form the coil 30. In this embodiment, the coil wire is wound clockwise around the outer periphery of the tooth 12 shown at the right end of FIG. 4 to form the coil 30, and then the coil wire is wound clockwise around the outer periphery of the adjacent (left) tooth 12 to form the coil 30. At this time, the coil wire drawn from the previously formed coil 30 is hooked to the terminal 42 and the tension relief mechanism 51 (a pair of tension relief parts 53) as shown in FIG. 7, and then the next coil 30 is formed. The arrows in Figure 7 indicate the order in which the coil wire is hooked onto the terminals 42, etc., with the right-hand side of the crossover wire 31 being the upstream side and the left-hand side being the downstream side.

In this way, 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 jumper wire 31 between the coils 30 to the terminal 42. In this embodiment, the tension of the jumper wire 31 is applied not only to the terminal 42 but also to the tension relief portion 53 provided near the terminal 42, so 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 approximately the same as the axial position of the support surface 42a of the terminal 42 that supports the jumper wire 31 from below. In addition, in the illustrated example, the region of the jumper wire 31 between the bent portions P2 of the pair of tension relief portions 53 extends linearly along a direction perpendicular to the axial direction (left and right direction in FIG. 7). As a result, approximately all of the tension applied to the region between the pair of bent portions P2 of the jumper wire 31 is applied to the pair of tension relief portions 53, and almost no load is applied to the terminal 42, so deformation of the terminal 42 can be reliably prevented.

The above steps are repeated to continuously form all the coils 30 with one coil wire, and then both ends of the coil wire are connected (see connection 31a in Figure 4). Then, each terminal 42 is electrically connected to each jumper wire 31. 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 Figure 7), electricity is passed through the terminal 42 and the jumper wire 31 via the jig 60. This generates heat at the contact point between the terminal 42 and the jumper wire 31, removing the insulating coating of the jumper wire 31 and welding the jumper wire 31 to the terminal 42, electrically connecting them.

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 a single 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, since no tension is applied to the jumper wire 31 having the connection parts 31a at both ends of the coil wire, 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 the 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.

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

As described above, by connecting adjacent coils 30 with jumper wires 31, 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), and all of the jumper wires 31 are arranged at equal circumferential intervals, 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, making design and manufacturing easier.

The tension relief mechanism 51 is provided with a fall prevention portion that prevents the jumper wire 31 from falling off. In this embodiment, as shown in Figures 3 and 6, a protrusion 54 that protrudes upward from the inner diameter end of the tension relief portion 53 functions as the fall prevention portion. The protrusion 54 engages from the inner diameter side with the jumper wire 31 hooked onto the upper surface 53a of the tension relief portion 53, thereby preventing the jumper wire 31 from falling off to the inner diameter side.

The present invention is not limited to the above embodiment. Other embodiments of the present invention will be described below, but duplicate explanations of points similar to the above embodiment will be omitted.

The jig 60 used to fuse the terminal 42 and the jumper wire 31 must be positioned above the tension relief mechanism 51 to avoid interference with the tension relief mechanism 51 (see FIG. 7). When the terminal 42 and the tension relief mechanism 51 are positioned so as to overlap partially in the axial direction as in the above embodiment, if the jig 60 is positioned above the tension relief mechanism 51, the jig 60 will not be able to clamp the entire terminal 42, which may cause problems during the fusing process.

In contrast, in the embodiment shown in FIG. 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.

In the embodiment shown in FIG. 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 of the jumper wire 31 formed by the pair of tension relief portions 53 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., in 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).

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

The electric motor 1 described above is incorporated, for example, in an electric oil pump provided in a vehicle with an idling stop function or a hybrid vehicle.

REFERENCE SIGNS LIST 1 Electric motor 2 Stator 3 Rotor 10 Stator core 11 Cylindrical portion 12 Teeth 20 Insulator 30 Coil 31 Crossover wire 40 Terminal unit 41 Terminal member 42 Terminal 43 Annular portion 50 Holding portion 51 Tension relief mechanism 52 Holding portion 53 Tension relief portion 54 Protruding portion 60 Jig P1 Contact portion P2 between crossover wire and terminal Bending portion of crossover wire by tension relief mechanism

Claims (13)

an annular stator core having a plurality of teeth;
A coil wound around each tooth;
a crossover wire connecting adjacent coils;
A terminal electrically connected to the crossover wire,
A stator in which adjacent coils and the jumper wires connecting them are formed of 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; The stator of claim 1, in which tension is applied to the area of the crossover wire between the contact portion with the terminal and the bent portion caused by the tension relief mechanism. The stator of claim 1, wherein the area of the crossover wire between the contact portion with the terminal and the bent portion caused by the tension relief mechanism extends in a direction perpendicular to the axial direction. The stator of claim 1, wherein the terminal is disposed at an axial position farther from the coil than the tension relief mechanism. The stator according to claim 1, wherein the tension relief mechanism has a pair of tension relief parts provided on both circumferential sides of the contact part between the crossover wire and the terminal. The stator according to claim 5, wherein the axial positions of the bent portions of the crossover wires caused by the pair of tension relief portions are different. The tension relief mechanism is
an upstream tension relief portion that contacts an area of the crossover wire that is upstream of a contact portion with the terminal;
a downstream tension relief portion that contacts a region of the crossover wire 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. The stator of claim 1, wherein the tension relief mechanism has a fall prevention part that engages with the crossover wire in a direction perpendicular to the axial direction. 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. The stator of claim 1, in which the crossover wire is disposed at a circumferential position closer to the downstream coil than the center of the circumferential region between the coils. 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. An electric motor having a stator according to claim 1 and a rotor disposed on the inner circumference of the stator. an annular stator core having a plurality of teeth;
A coil wound around each tooth;
a crossover wire connecting adjacent coils;
A terminal electrically connected to the crossover wire,
A manufacturing method of a stator in which adjacent coils and the jumper wires connecting the adjacent coils are 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.

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