JP7172809B2 - Rotating electric machine - Google Patents

Description

The present disclosure relates to rotating electric machines.

2. Description of the Related Art Conventionally, a rotating electric machine having a rotor and a stator has been used. Patent Literature 1 discloses a rotating electric machine in which, of the coils that constitute a stator, the coils on the stator core tooth side are made of aluminum wire, and the remaining coils are made of copper wire.

JP 2010-183788 A

As a method for joining dissimilar metal wires such as an aluminum wire and a copper wire, the inventor of the present application joins two types of segment coils made of dissimilar metals to each other at the ends of the segment coils located at the coil ends. I assumed. However, the inventors of the present application have found that when dissimilar metal wires are joined at the ends of the coil ends, the required strength at such joints may increase. Such a problem is common not only when a segment coil is used as a coil, but also when a continuous coil is wound. Therefore, there is a demand for a technique capable of suppressing an increase in the required strength at the junction of dissimilar metal wires.

The present disclosure can be implemented as the following forms.

According to one aspect of the present disclosure, a rotating electrical machine (10) is provided. This rotating electric machine has a rotor (20) and a stator (30, 30a to 30f). The stator includes a stator core (40) formed with a plurality of slots (42) arranged in a circumferential direction an in-slot coil (52) accommodated in each of the plurality of slots, a pair of coil ends (54) connected to the in-slot coil and positioned outside the plurality of slots, and a lead wire connecting to the coil end a coil (50, 50a-50f) having (56, 56a, 56b), wherein the coil comprises a first metal wire portion (71) made of a first metal; A second metal wire portion (72) made of a second metal having a higher electrical resistance than metal, and a joint portion (72) where the first metal wire portion and the second metal wire portion are joined to each other 73), wherein the joint portion is located in the in-slot coil, the in-slot coil is formed in a plurality of layers in a radial direction inside the plurality of slots, and the pair of coil ends is formed of a plurality of layers corresponding to the in-slot coil, and at least one coil end of the pair of coil ends has all the layers of the first metal wire portion or the first metal wire portion. It is composed of a single type of metal wire portion, either one of the two metal wire portions .

According to this aspect of the rotating electric machine, the joint portion where the first metal wire portion and the second metal wire portion are joined to each other is located in the in-slot coil accommodated inside the slot of the stator core. Therefore, compared to a configuration in which the first metal wire portion and the second metal wire portion are joined to each other at the coil end, the stress applied to the joint portion can be reduced, and an increase in required strength can be suppressed. Therefore, it is possible to suppress an increase in the required strength at the junction of dissimilar metal wires.

The present disclosure may also be embodied in various forms. For example, it can be implemented in the form of a method for manufacturing an electric motor, a generator, or a rotating electric machine.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows schematic structure of the rotary electric machine of 1st Embodiment. FIG. 2 is a cross-sectional view showing the stator in a cross section taken along line II-II of FIG. 1; 3 is an enlarged cross-sectional view showing an enlarged region III of FIG. 2; FIG. FIG. 4 is a cross-sectional view schematically showing a cross section taken along line IV-IV of FIG. 3; It is a schematic diagram which shows schematic structure of a segment coil. FIG. 5 is a cross-sectional view showing a schematic configuration of a stator in a second embodiment; FIG. 11 is a cross-sectional view showing a schematic configuration of a stator in a third embodiment; FIG. 11 is a cross-sectional view showing a schematic configuration of a stator in a fourth embodiment; FIG. 11 is a cross-sectional view showing a schematic configuration of a stator in a fifth embodiment; FIG. 11 is a cross-sectional view showing a schematic configuration of a stator in a sixth embodiment; FIG. 11 is a cross-sectional view showing a schematic configuration of a stator in a seventh embodiment;

A. First embodiment:
A rotating electric machine 10 shown in FIG. 1 is configured as a so-called inner rotor type permanent magnet synchronous motor, and is mounted on a vehicle (not shown). The rotating electrical machine 10 includes a housing 15 , a rotor 20 and a stator 30 . Housing 15 accommodates rotor 20 and stator 30 .

The rotor 20 has a substantially cylindrical external shape, and rotates around the rotation axis AX. The rotor 20 has a rotor core 22 and a rotating shaft 26 . The rotor core 22 is composed of a plurality of steel plates laminated along the axial direction. A plurality of permanent magnets 24 are embedded in the rotor core 22 . Note that the plurality of permanent magnets 24 may be exposed on the outer peripheral surface of the rotor core 22 . The rotating shaft 26 is fixed radially inside the rotor core 22 . The rotating shaft 26 is rotatably supported with respect to the housing 15 by bearings 18 provided at both ends of the housing 15 .

The stator 30 has a substantially cylindrical external shape, and is arranged radially outside of the rotor 20 with a gap therebetween. Stator 30 has a stator core 40 and coils 50 .

The stator core 40 is composed of a plurality of steel plates laminated along the axial direction. As shown in FIG. 2, a plurality of slots 42 are formed along the inner circumference of the stator core 40 in the circumferential direction. Each slot 42 is recessed radially outward over the entire axial direction of the stator core 40 . A coil 50 is wound around each slot 42 . The coil 50 is configured as a three-phase coil 50 consisting of a U-phase, a V-phase, and a W-phase.

As shown in FIG. 3, the coil 50 of the present embodiment is formed of a metal wire having a rectangular cross-sectional shape called a rectangular wire. In this embodiment, the cross-sectional shape is substantially rectangular, but it is not limited to substantially rectangular and may be substantially square or the like. An insulating film (not shown) is formed on the surface of the metal wire material forming the coil 50 . Such an insulating film ensures insulation between adjacent wires and stator core 40 . Insulating paper (not shown) is arranged on the wall surface of the slot 42 of the stator core 40, and the insulation between the coil 50 and the stator core 40 is also ensured by this insulating paper.

As shown in FIG. 4 , the coil 50 has an in-slot coil 52 , coil ends 54 and lead wires 56 . The in-slot coils 52 are accommodated inside the respective slots 42 . The in-slot coil 52 is fixed to the stator core 40 by filling the gap inside the slot 42 with an impregnation process after being inserted inside the slot 42 . The coil end 54 is formed continuously with the in-slot coil 52 and positioned outside the slot 42 . More specifically, the coil ends 54 protrude axially outward from the stator core 40 . The lead wire 56 is formed continuously from the coil end 54 and connected to a terminal of an external lead wire (not shown). Electric power is supplied to the rotating electric machine 10 through such external lead wires.

As shown in FIGS. 3 and 4, the coil 50 of this embodiment has six layers of in-slot coils 52 formed in one slot 42 . In the following description, the six layers of the in-slot coils 52 are arranged in order from the inner side in the radial direction: a first layer 61, a second layer 62, a third layer 63, a fourth layer 64, a fifth layer 65, and a sixth layer 66. Also called The first layer 61 is closest to the rotor 20 among the in-slot coils 52 . For this reason, the first layer 61 is also called "adjacent layer 61". Further, the lead wire 56 in this embodiment is formed so as to continue to the coil end 54 that continues to the in-slot coil 52 of the sixth layer 66 . In this embodiment, the six-layered in-slot coils 52 in one slot 42 are all formed of the same phase among the three phases of U phase, V phase, and W phase.

The coil 50 of this embodiment is composed of metal wires made of two different materials. More specifically, it is composed of a copper wire 71 and an aluminum wire 72 . In general, aluminum has the characteristics of high electrical resistance, low strength, and light mass compared to copper.

The ends of the copper wire 71 and the aluminum wire 72 are joined together at the joining portion 73 . The joint portion 73 is located in the in-slot coil 52 and accommodated in the slot 42 . A method of joining the copper wire 71 and the aluminum wire 72 at the joining portion 73 will be described later. At the time of joining, the insulating films respectively formed on the surface of the copper wire 71 and the surface of the aluminum wire 72 are removed.

In the present embodiment, of the six layers of the in-slot coils 52, three radially outer layers, that is, the fourth layer 64, the fifth layer 65, and the sixth layer 66, are composed of copper wires 71, and the radially inner Two layers, the adjacent layer 61 and the second layer 62 are made up of aluminum wires 72 . The third layer 63 is configured by joining a copper wire 71 and an aluminum wire 72 at a joining portion 73 . In the rotary electric machine 10 of the present embodiment, by configuring the six-layer in-slot coils 52 in this manner, an increase in loss of the coils 50 described below is suppressed.

Losses in coil 50 can be approximated as the sum of resistive losses and winding eddy current losses. Resistance loss increases in proportion to the electrical resistance of the metal material forming the coil 50 . Therefore, the resistance loss of the aluminum wire 72 tends to be greater than the resistance loss of the copper wire 71 . In addition, since the value depends on the type of metal material, the ohmic loss of the layers made of the same metal material among the six-layer in-slot coils 52 all have the same value. Resistance loss occurs not only in the in-slot coil 52 but also in the coil ends 54 and the lead wires 56 . Also, resistance loss tends to decrease as the cross-sectional area of the coil 50 increases.

Winding eddy current loss is a loss that mainly occurs in the in-slot coils 52 arranged facing the rotor 20 . Since the winding eddy current loss depends on the magnitude of the interlinking magnetic flux, it tends to be larger in the radially inner layers among the six-layered in-slot coils 52 . More specifically, for example, in the adjacent layer 61, a large amount of magnetic flux is interlinked, resulting in large winding eddy current loss. do not do. Also, the winding eddy current loss is inversely proportional to the electrical resistance of the metal material forming the coil 50 . Therefore, the winding eddy current loss of the copper wire 71 tends to be greater than the winding eddy current loss of the aluminum wire 72 .

In this embodiment, among the multiple layers of the in-slot coils 52, the radially inner layer, which is greatly affected by the winding eddy current loss, is composed of the aluminum wire 72, thereby suppressing an increase in the winding eddy current loss. is doing. In addition, among the multiple layers of the in-slot coils 52, the radially outer layer, which is less affected by the winding eddy current loss, is made of the copper wire 71, thereby suppressing an increase in resistance loss. That is, by configuring the radially inner layer with the aluminum wire 72 and configuring the radially outer layer with the copper wire 71, the total value of the resistance loss and the winding eddy current loss can be approximated. This suppresses an increase in the loss of the coil 50 as a whole.

As shown in FIG. 5, the coil 50 of this embodiment is formed of a plurality of segment coils 80. As shown in FIG. A segment coil 80 shown on the right side of the paper surface in FIG. 5 schematically shows the segment coil 80 forming part of the third layer 63 . Each segment coil 80 is formed by bending a wire into a substantially hexagonal shape. The segment coil 80 has a pair of linear portions 82 , a pair of mountain-shaped portions 84 and a pair of end portions 86 . The pair of linear portions 82 are housed in different slots 42 to form in-slot coils 52 . The pair of mountain-shaped portions 84 respectively constitute the coil ends 54 . The pair of end portions 86 correspond to the end portions of the wire forming the segment coil 80 and are positioned at the top of one of the pair of mountain-shaped portions 84 . Such end portions 86 are joined to end portions 86 of other segment coils 80 . Therefore, the segment coils 80 are joined together at the coil ends 54 .

In the coil 50 formed by a plurality of segment coils 80, the inventors of the present application proposed a method for forming the multilayer in-slot coil 52 of the copper wire 71 and the aluminum wire 72 having the above-described configuration, using only the copper wire 71. It was assumed that the formed segment coil 80 and the segment coil 80 formed only by the aluminum wire 72 would be joined together at the end portions 86 . However, the inventors of the present application have found that when the copper wire 71 and the aluminum wire 72 are joined in this manner, the required strength at the joint may increase.

As described above, the in-slot coils 52 are housed inside the slots 42 and fixed to the stator core 40 by impregnation. On the other hand, since the coil ends 54 are exposed from the stator core 40 , they are more susceptible to vibrations of the vehicle than the in-slot coils 52 . Therefore, the stress applied to the chevron-shaped portion 84 , ie, the coil end 54 , due to vibration of the vehicle is greater than the stress applied to the linear portion 82 , ie, the in-slot coil 52 .

The segment coil 80 is formed by bending a wire so as to have a substantially hexagonal external shape. For this reason, the ends 86 of the segment coils 80 are pulled in a direction in which they are attracted to each other and joined together, so that stress is applied. Furthermore, the ends 86 of the segment coils 80 are stressed in the direction that they press together when the chevrons 84 thermally expand. Thus, due to the shape of the segment coil 80, stress is applied to the mountain-shaped portion 84 having the end portion 86 formed thereon.

Therefore, when the copper wire 71 and the aluminum wire 72 are joined at the end portion 86 of the segment coil 80 located at the coil end 54, the above-described stress is applied, increasing the required strength at the joint. On the other hand, in the stator 30 of the present embodiment, the copper wire 71 and the aluminum wire 72 are joined at the joint portion 73 located in the in-slot coil 52, thereby suppressing an increase in the required strength at the joint portion. there is

In this embodiment, copper corresponds to a subordinate concept of the first metal in the present disclosure, and the copper wire 71 corresponds to a subordinate concept of the first metal wire portion in the present disclosure. In addition, aluminum corresponds to a subordinate concept of the second metal in the present disclosure, and the aluminum wire 72 corresponds to a subordinate concept of the second metal wire portion in the present disclosure.

According to the rotary electric machine 10 of the first embodiment described above, the joint portion 73 where the copper wire 71 and the aluminum wire 72 are joined to each other is positioned in the in-slot coil 52 accommodated inside the slot 42 of the stator core 40 . is doing. Therefore, compared to the configuration in which the copper wire 71 and the aluminum wire 72 are joined together at the coil end 54, the stress applied to the joint portion 73 can be reduced, and an increase in the required strength of the joint portion 73 can be suppressed. Therefore, it is possible to suppress an increase in the required strength at the joint portion 73 of the dissimilar metal wires, thereby suppressing complication and weight increase of the structure for ensuring the strength.

Further, among the multiple layers of the in-slot coils 52, the radially inner layer, which is greatly affected by the winding eddy current loss, is composed of the aluminum wire 72, so that an increase in the winding eddy current loss can be suppressed. In addition, among the multiple layers of the in-slot coil 52, the radially outer layer, which is less affected by winding eddy current loss, is composed of the copper wire 71, so that an increase in resistance loss can be suppressed. Therefore, an increase in the overall loss of the coil 50, which is approximated to the total value of the resistance loss and the winding eddy current loss, can be suppressed, so that the temperature rise of the stator 30 can be suppressed, and the efficiency of the rotating electric machine 10 can be lowered. can be suppressed. In addition, since an increase in winding eddy current loss can be suppressed, it is suitable for the rectangular wire coil 50 in which winding eddy current loss tends to increase.

In addition, since the coil 50 is formed of the copper wire 71 and the aluminum wire 72, the weight of the rotary electric machine 10 can be reduced and the material cost of the coil 50 can be reduced as compared with a structure formed only of the copper wire 71. An increase in the manufacturing cost of the rotary electric machine 10 due to the increase can be suppressed.

In addition, since the joint portion 73 is located in the in-slot coil 52 , the configuration for ensuring insulation at the joint portion 73 can be simplified, and a decrease in reliability of the rotating electric machine 10 can be suppressed. The reason for this will be explained below.

Since the segment coils 80 of different phases are adjacent to each other at the coil end 54, the potential difference between the adjacent segment coils 80 is large. On the other hand, since the six-layered in-slot coils 52 in one slot 42 are formed of one of the three phases of U phase, V phase, and W phase, the joint from which the insulating film is removed The layer of the in-slot coil 52 that is radially adjacent to the portion 73 has the same phase and a small potential difference. Therefore, the insulation required between the radially adjacent in-slot coils 52 at the joint portion 73 from which the insulating film has been removed is such that the copper wire 71 and the aluminum wire 72 are joined to each other at the coil end 54. Small compared to configuration. Also, the insulation required between the joints 73 and the slots 42 of the stator core 40 is less than the insulation required between different phases, that is, the insulation required at the coil ends 54 . Such relatively low insulation may be ensured by the insulation of an insulation film preformed on the surface of the radially adjacent in-slot coils 52 . That is, forming a new insulating film on the surface of the joint portion 73 from which the insulating film has been removed may be omitted, and complication of the manufacturing process can be suppressed. Also, in the configuration in which a new insulating film is formed on the surface of the joint portion 73, the insulation can be supplemented by the insulating film previously formed on the surfaces of the radially adjacent in-slot coils 52. The thickness of the insulating coating can be made thinner than the thickness of the insulating coating previously formed on the copper wire 71 and the aluminum wire 72 .

Further, according to the rotary electric machine 10 of the present embodiment, the lead wire 56 is made of the copper wire 71, so that it is possible to suppress a decrease in the strength of the lead wire 56, which is easily affected by vibrations of the vehicle.

In addition, since the coil 50 is composed of a plurality of segment coils 80, the space factor in the slot 42 can be improved, an increase in the size of the rotary electric machine 10 can be suppressed, and a higher output can be achieved. Moreover, since it is composed of the segment coils 80 , it is possible to suppress the position of the joint portion 73 from deviating from the in-slot coils 52 , compared to a configuration in which a continuous coil is wound around the stator core 40 . In addition, since the coil 50 is composed of a so-called rectangular wire, the space factor in the slot 42 can be improved, the enlargement of the rotary electric machine 10 can be suppressed, and high output can be realized.

B. Second embodiment:
A stator 30a included in the rotating electrical machine of the second embodiment shown in FIG. Since other configurations are the same as those of the first embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

The lead wire 56a of the coil 50a of the second embodiment is formed so as to be connected to the coil end 54 connected to the in-slot coil 52 of the proximity layer 61 . Therefore, the lead wire 56 a is composed of the aluminum wire 72 . In the coil 50a provided in the stator 30a of the second embodiment, the radially outer two layers, that is, the fifth layer 65 and the sixth layer 66 of the six layers of the in-slot coils 52 are made of copper wires 71. , the radially inner three layers, ie, the adjacent layer 61 , the second layer 62 and the third layer 63 , are composed of aluminum wires 72 . The fourth layer 64 is configured by joining a copper wire 71 and an aluminum wire 72 at a joining portion 73 located in the in-slot coil 52 .

The rotating electrical machine of the second embodiment described above has the same effects as the rotating electrical machine 10 of the first embodiment. In addition, since the lead wire 56a is formed so as to continue to the coil end 54 connected to the in-slot coil 52 of the adjacent layer 61, there are restrictions on the arrangement of external lead wires (not shown), for example, to the outside of the stator 30a in the radial direction. It can also be applied when there are restrictions such as not being able to arrange external lead wires. Therefore, it is possible to prevent external lead wires and the like from protruding radially outward of the stator 30a, and to prevent the stator 30a from increasing in size.

C. Third embodiment:
A stator 30b included in the rotating electrical machine of the third embodiment shown in FIG. 7 differs from the rotating electrical machine of the second embodiment in that a coil 50b is provided instead of the coil 50a. Since other configurations are the same as those of the second embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

The lead wires 56b of the coils 50b included in the stator 30b of the third embodiment are composed of copper wires 71. As shown in FIG. Of the six-layer in-slot coils 52 of the coil 50b, the fifth layer 65 and the sixth layer 66 are composed of copper wires 71, and the second layer 62 and the third layer 63 are composed of aluminum wires 72. . The fourth layer 64 and the adjacent layer 61 are each formed by joining a copper wire 71 and an aluminum wire 72 at a joining portion 73 located in the in-slot coil 52 . Therefore, two joints 73 are formed in the coil 50b. In this embodiment, most of the proximity layer 61 is composed of aluminum wires 72 .

The rotating electrical machine of the third embodiment described above has the same effects as the rotating electrical machine of the second embodiment. In addition, since the lead wire 56b is made of the copper wire 71, it is possible to suppress a decrease in the strength of the lead wire 56b. In addition, since a portion of the adjacent layer 61 is made of the aluminum wire 72, an increase in the winding eddy current loss can be suppressed in the adjacent layer 61 where the magnetic flux is large and the winding eddy current loss tends to increase.

D. Fourth embodiment:
A stator 30c included in the rotating electrical machine of the fourth embodiment shown in FIG. 8 differs from the rotating electrical machine of the third embodiment in that a coil 50c is provided instead of the coil 50b. Since other configurations are the same as those of the third embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

Most of the coil 50c included in the stator 30c of the fourth embodiment is composed of the aluminum wire 72 except for the lead wire 56b. More specifically, of the six layers of the in-slot coil 52 of the coil 50c, the second layer 62 to the sixth layer 66 are composed of the aluminum wires 72, and the adjacent layer 61 is composed of the copper wires 71 and the aluminum wires 72. are joined at a joint portion 73 located in the in-slot coil 52 . In this embodiment, most of the proximity layer 61 is composed of aluminum wires 72 .

The rotary electric machine of the fourth embodiment described above has the same effect as the rotary electric machine of the third embodiment. In addition, since most of the wires except the lead wires 56b are made of the aluminum wire 72, the weight of the stator 30c can be suppressed, and the weight of the rotating electric machine can be suppressed. Also, an increase in the material cost of the coil 50c can be suppressed.

E. Fifth embodiment:
A stator 30d included in the rotating electrical machine of the fifth embodiment shown in FIG. 9 differs from the rotating electrical machine 10 of the first embodiment in that a coil 50d is provided instead of the coil 50. Since other configurations are the same as those of the first embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

All the coil ends 54 of the coil 50 d of the fifth embodiment are made of copper wire 71 . Note that almost no winding eddy current loss occurs at the coil end 54 . Of the six-layered in-slot coils 52 of the coil 50d, four radially outer layers, that is, the third layer 63 to the sixth layer 66, are composed of copper wires 71, and the radially inner two layers, that is, the adjacent layers 61 are composed of copper wires 71. and the second layer 62 are formed by joining a copper wire 71 and an aluminum wire 72 at a joining portion 73 located in the in-slot coil 52 . Therefore, four joint portions 73 are formed in the coil 50d.

The rotating electrical machine of the fifth embodiment described above has the same effects as the rotating electrical machine 10 of the first embodiment. In addition, since the coil ends 54 are made of the copper wire 71, an increase in resistance loss at the coil ends 54 can be suppressed. Therefore, it is possible to suppress an increase in the loss of the coil 50d as a whole, which is approximated to the total value of the resistance loss and the winding eddy current loss. In addition, since the coil ends 54 are formed of the copper wire 71, it is possible to suppress deterioration in the strength of the coil ends 54, which are susceptible to vibration. In addition, since all the coil ends 54 are formed of the copper wire 71, it is possible to further suppress an increase in resistance loss in the coil ends 54 and further suppress a decrease in strength.

F. Sixth embodiment:
A stator 30e included in the rotating electrical machine of the sixth embodiment shown in FIG. 10 differs from the rotating electrical machine of the fourth embodiment in that a coil 50e is provided instead of the coil 50c. Since other configurations are the same as those of the fourth embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

All of the coil ends 54 of the coil 50 e of the sixth embodiment are made of copper wire 71 . All layers of the in-slot coil 52 of the coil 50 e are configured by joining copper wires 71 and aluminum wires 72 at two joints 73 located in the in-slot coil 52 . Therefore, 12 joints 73 are formed in the coil 50e.

The rotary electric machine of the sixth embodiment described above has the same effect as the rotary electric machine of the fourth embodiment. In addition, since the coil ends 54 are made of the copper wire 71, an increase in resistance loss at the coil ends 54 can be suppressed. Therefore, it is possible to suppress an increase in loss of the coil 50e as a whole, which is approximated to the total value of resistance loss and winding eddy current loss. Moreover, since all the coil ends 54 are formed of the copper wire 71, an increase in resistance loss at the coil ends 54 can be further suppressed.

G. Seventh embodiment:
A stator 30f included in the rotating electrical machine of the seventh embodiment shown in FIG. 11 differs from the rotating electrical machine of the fifth embodiment in that a coil 50f is provided instead of the coil 50d. Since other configurations are the same as those of the fifth embodiment, the same configurations are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the coil 50d of the seventh embodiment, two bonding portions 73 are formed in each of the adjacent layer 61 and the second layer 62. As shown in FIG. The joints 73 respectively formed in the adjacent layer 61 and the second layer 62 have different positions in the axial direction of the stator 30 . That is, the positions of the joints 73 in the radially adjacent layers accommodated in the same slot 42 are shifted in the axial direction.

The rotating electrical machine of the seventh embodiment described above has the same effect as the rotating electrical machine of the fifth embodiment. In addition, since the positions of the joints 73 in the layers adjacent to each other in the radial direction are shifted in the axial direction, the insulation to be ensured at the joints 73 from which the insulation film has been removed can be achieved by the in-slot coils 52 adjacent in the radial direction. can be complemented by the insulating properties of the insulating film preliminarily formed on the surface. Therefore, it is possible to omit forming a new insulating film on the surface of the joint portion 73 from which the insulating film has been removed, thereby suppressing complication of the manufacturing process. Also, in the structure in which a new insulating film is formed on the surface of the joint portion 73 , the thickness of the insulating film can be made thinner than the thickness of the insulating film formed on the copper wire 71 and the aluminum wire 72 . In addition, it is possible to suppress the occurrence of partial discharge due to deterioration of the insulation in the joint portion 73 .

H. Other embodiments:
H-1. Alternative Embodiment 1:
In the seventh embodiment, the positions of the joints 73 in the layers adjacent to each other in the radial direction are shifted in the axial direction. may be formed. For example, in the stator 30b of the third embodiment shown in FIG. 7, the positions of the joints 73 respectively formed in the fourth layer 64 and the adjacent layer 61 may be offset from each other in the axial direction. For example, in a structure in which joint portions 73 are respectively formed in the adjacent layer 61 and the third layer 63, the positions of the joint portions 73 may be shifted from each other in the axial direction. That is, in general, multiple layers of in-slot coils may have a plurality of joints at different positions in the axial direction of the stator. Such a configuration also provides the same effects as the seventh embodiment.

H-2. Alternative Embodiment 2:
The configurations of the coils 50, 50a to 50f in each of the above-described embodiments are merely examples, and various modifications are possible. For example, instead of the copper wire 71, a silver wire made of silver may be used, a copper dividing line formed by bundling a plurality of fine copper wires may be used, and the aluminum wire 72 may be replaced with Alternatively, an aluminum parting line formed by bundling a plurality of thin aluminum wires may be used. Also, for example, it may be formed of three or more kinds of metal wires. Further, for example, a continuous coil may be wound around the stator core 40 instead of the plurality of segment coils 80 . Further, for example, instead of the wire rod having a rectangular cross-sectional shape, the wire rod may be formed of a wire rod having an arbitrary cross-sectional shape such as a round shape. Even with such a configuration, the same effects as those of the rotating electric machine 10 of each of the above-described embodiments can be obtained.

H-3. Alternative Embodiment 3:
The configurations of the stators 30, 30a to 30f in each of the above-described embodiments are merely examples, and various modifications are possible. For example, some of the layers of the intra-slot coils 52 formed in one slot 42 may be formed of different phases. Further, for example, the number of layers of the in-slot coil 52 formed in one slot 42 is not limited to six layers, and may be any number, such as four layers, eight layers, or even one layer. There may be. Even with such a configuration, the same effects as those of the rotating electric machine 10 of each of the above-described embodiments can be obtained.

H-4. Alternative Embodiment 4:
The rotating electric machine 10 of each of the above-described embodiments is configured as an inner rotor type permanent magnet synchronous motor, but may be configured as any other synchronous motor or induction motor, and may be configured as an outer rotor type electric motor. or may be configured as a generator. In addition, it may be mounted on any moving object such as an airplane or a ship without being limited to a vehicle, or may be installed on a fixed object instead of being mounted on a moving object.

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the scope of the present disclosure. For example, the technical features in the embodiments corresponding to the technical features in the respective modes described in the Summary of the Invention column may be used to solve some or all of the above problems, or Substitutions and combinations may be made as appropriate to achieve part or all. Also, if the technical features are not described as essential in this specification, they can be deleted as appropriate.

10 rotating electric machine, 20 rotor, 30, 30a to 30f stator, 40 stator core, 42 slot, 50, 50a to 50f coil, 52 coil in slot, 54 coil end, 56, 56a, 56b lead wire, 71 copper wire (first metal wire portion), 72 aluminum wire (second metal wire portion), 73 joint portion

Claims (9)

A rotating electric machine (10) having a rotor (20) and stators (30, 30a to 30f),
The stator includes a stator core (40) in which a plurality of slots (42) are arranged in a circumferential direction, in-slot coils (52) respectively accommodated in the plurality of slots, and the in-slot coils connected to each other. Coils (50, 50a to 50f) having a pair of coil ends (54) positioned outside a plurality of slots and lead wires (56, 56a, 56b) connected to the coil ends,
The coil includes a first metal wire portion (71) made of a first metal and a second metal wire portion (72) made of a second metal having higher electrical resistance than the first metal. ) and a joint portion (73) where the first metal wire portion and the second metal wire portion are joined to each other,
the joint is located in the in-slot coil;
The in-slot coil is formed in a plurality of layers in the radial direction inside the plurality of slots,
Each of the pair of coil ends is formed of a plurality of layers corresponding to the in-slot coil,
In at least one coil end of the pair of coil ends, all layers are composed of a single type of metal wire portion, either the first metal wire portion or the second metal wire portion. ing,
rotating electric machine. In the rotary electric machine according to claim 1,
Of the pair of coil ends, at the coil end to which the lead wire is connected, the layer connected to the lead wire is composed of the first metal wire portion, and all other layers are composed of the second metal wire portion. Consists of a metal wire part,
Of the pair of coil ends, at the coil end to which the lead wire is not connected, all layers are composed of the second metal wire portion,
rotating electric machine . In the rotary electric machine according to claim 1 ,
In each of the pair of coil ends , all layers are composed of the first metal wire portion,
rotating electric machine. In the rotating electric machine according to any one of claims 1 to 3 ,
The coil is formed by a plurality of segment coils (80),
rotating electric machine. In the rotating electric machine according to any one of claims 1 to 4 ,
The coil is formed of a wire having a rectangular cross-sectional shape,
rotating electric machine. In the rotating electric machine according to any one of claims 1 to 5 ,
At least a part of the adjacent layer (61) closest to the rotor among the multiple layers of the in-slot coils is composed of the second metal wire portion,
rotating electric machine. In the rotating electric machine according to any one of claims 1 to 6 ,
The lead wire is composed of the first metal wire portion,
rotating electric machine. In the rotating electric machine according to any one of claims 1 to 7 ,
the first metal is copper and the second metal is aluminum;
rotating electric machine. In the rotating electric machine according to any one of claims 1 to 8 ,
A plurality of the joint portions having different positions in the axial direction of the stator are positioned in the in-slot coils of the plurality of layers.
rotating electric machine.

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