JP2024077152A - Stator, rotary electric machine, and driving device - Google Patents

Abstract

To suppress deterioration of torque in a rotary electric machine while preventing a part of an insulation sheet from being scraped when the insulation sheet is arranged in a slot part.SOLUTION: A stator 10 includes: a stator core 20 which has core backs 21 and teeth 22 and in which slot parts 23 are provided between the adjacent teeth in a circumferential direction; conductor parts 31 positioned in the slot parts; and an insulation sheet 40 whose at least a part is positioned between the conductor part and the stator core in the slot part. An inner edge of the slot part 23 includes a first connection part 23a being a connection part between one face of the tooth in the circumferential direction and one face of the core back in a radial direction and a second connection part 23b being a connection part between the other face of the tooth in the circumferential direction and one face side of the core back in the radial direction when viewed in an axial direction. The first connection part and the second connection part are in shapes which are asymmetrical to each other with respect to a virtual line CL1 which passes through a center in the circumferential direction of the slot part and extends in the radial direction when viewed in the axial direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to a stator, a rotating electric machine, and a drive device.

In rotating electrical machines, a configuration is known in which an insulating sheet is disposed in the slots between the teeth of a stator core. For example, Patent Document 1 describes a configuration in which a recess in which a part of the insulating sheet is disposed is provided on the side of the tooth.

JP 2012-39742 A

In rotating electric machines like the one described above, when placing an insulating sheet in a slot, there is a risk that easily worn parts of the insulating sheet, such as the ends, may come into contact with the stator core and be worn away. This can cause problems such as parts of the worn insulating sheet remaining inside the rotating electric machine. In response to this, for example, in Patent Document 1, it is conceivable to prevent parts of the insulating sheet from coming into contact with the stator core and being worn away by placing parts of the insulating sheet, such as the ends, that are easily worn away in recesses provided on the side surfaces of the teeth. However, in this case, the teeth become thinner in the circumferential direction by the amount of the recesses, and the amount of magnetic flux flowing through the teeth decreases. This causes a problem of reduced torque in the rotating electric machine.

In view of the above circumstances, one of the objects of the present invention is to provide a stator, a rotating electric machine, and a drive unit having a structure that can prevent a portion of the insulating sheet from being scraped off when the insulating sheet is placed in the slot portion, while preventing a decrease in the torque of the rotating electric machine.

One aspect of the stator of the present invention includes a stator core having an annular core back surrounding a central axis, and a plurality of teeth extending from the core back to one radial side and spaced apart in the circumferential direction, with a slot provided between each of the circumferentially adjacent teeth, a conductor portion located within the slot portion, and an insulating sheet at least a portion of which is located within the slot portion between the conductor portion and the stator core. When viewed in the axial direction, the inner edge of the slot portion has a first connection portion that is a connection portion between the surface of the tooth on one circumferential side and the surface of the core back on one radial side, and a second connection portion that is a connection portion between the surface of the tooth on the other circumferential side and the surface of the core back on one radial side. When viewed in the axial direction, the first connection portion and the second connection portion are asymmetrical with each other across a virtual line that passes through the circumferential center of the slot portion and extends in the radial direction.

One embodiment of the rotating electric machine of the present invention comprises the above-mentioned stator and a rotor that faces the stator with a radial gap therebetween.

One embodiment of the drive device of the present invention includes the above-mentioned rotating electric machine and a gear mechanism connected to the rotating electric machine.

According to one aspect of the present invention, in a rotating electric machine and a drive unit, it is possible to prevent a portion of the insulating sheet from being scraped off when the insulating sheet is placed in a slot portion, while preventing a decrease in the torque of the rotating electric machine.

FIG. 1 is a diagram illustrating a schematic diagram of a drive device according to a first embodiment. FIG. 2 is a diagram showing a stator core according to the first embodiment. FIG. 3 is a cross-sectional view showing a portion of the stator in the first embodiment. FIG. 4 is a cross-sectional view showing a part of the stator in the first embodiment, which is an enlarged partial view of FIG. FIG. 5 is a cross-sectional view showing a part of a stator core according to the second embodiment.

In the following description, the vertical direction is defined based on the positional relationship when the drive device of the embodiment is mounted on a vehicle positioned on a horizontal road surface. In other words, the relative positional relationship in the vertical direction described in the following embodiment only needs to be satisfied when the drive device is mounted on a vehicle positioned on a horizontal road surface.

In the drawings, the XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction is simply called the "upper side", and the lower side in the vertical direction is simply called the "lower side". The X axis direction is a direction perpendicular to the Z axis direction and is the front-rear direction of the vehicle on which the drive unit is mounted. In the following embodiments, the +X side is the front side of the vehicle, and the -X side is the rear side of the vehicle. The Y axis direction is a direction perpendicular to both the X axis direction and the Z axis direction, and is the left-right direction of the vehicle, i.e., the vehicle width direction. In the following embodiments, the +Y side is the left side of the vehicle, and the -Y side is the right side of the vehicle. The front-rear direction and the left-right direction are horizontal directions perpendicular to the vertical direction.

The positional relationship in the front-rear direction is not limited to that in the following embodiment, and the +X side may be the rear side of the vehicle, and the -X side may be the front side of the vehicle. In this case, the +Y side is the right side of the vehicle, and the -Y side is the left side of the vehicle. In this specification, "parallel direction" also includes a substantially parallel direction, and "perpendicular direction" also includes a substantially perpendicular direction.

The central axis J, which is shown in the appropriate figures, is a virtual axis that extends in a direction that intersects with the vertical direction. More specifically, the central axis J extends in the Y-axis direction that is perpendicular to the vertical direction, that is, in the left-right direction of the vehicle. In the following description, unless otherwise specified, the direction parallel to the central axis J will be simply referred to as the "axial direction", the radial direction centered on the central axis J will be simply referred to as the "radial direction", and the circumferential direction centered on the central axis J, that is, around the axis of the central axis J, will be simply referred to as the "circumferential direction".

In the following description, the left side (+Y side) is referred to as "one axial side" and the right side (-Y side) is referred to as "the other axial side". The arrow θ shown in the figures indicates the circumferential direction. In the following description, the side in the circumferential direction that progresses clockwise around the central axis J as viewed from the right side (-Y side), i.e., the side to which the arrow θ points (+θ side), is referred to as "one circumferential side", and the side in the circumferential direction that progresses counterclockwise around the central axis J as viewed from the right side, i.e., the opposite side to the side to which the arrow θ points (-θ side), is referred to as "the other circumferential side". In the following embodiments, the radially inner side corresponds to the "one radial side" and the radially outer side corresponds to the "other radial side".

First Embodiment
A drive device 100 according to the present embodiment shown in Fig. 1 is a drive device mounted on a vehicle and rotates an axle 73. The vehicle on which the drive device 100 is mounted is a vehicle that uses a motor as a power source, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV). As shown in Fig. 1, the drive device 100 includes a rotating electric machine 60, a gear mechanism 70 connected to the rotating electric machine 60, a housing 80 that accommodates the rotating electric machine 60 and the gear mechanism 70 therein, and a control device 64 that controls the rotating electric machine 60. In this embodiment, the rotating electric machine 60 is a motor.

The housing 80 houses the rotating electric machine 60 and the gear mechanism 70 inside. The housing 80 has a motor housing 81 that houses the rotating electric machine 60 inside, and a gear housing 82 that houses the gear mechanism 70 inside. In this embodiment, oil O is contained inside the motor housing 81 and the gear housing 82.

The gear mechanism 70 transmits the rotation of the rotating electric machine 60 to the vehicle axle 73. The gear mechanism 70 has a reduction gear 71 connected to the rotating electric machine 60, and a differential gear 72 connected to the reduction gear 71. The differential gear 72 is connected to the axle 73.

The rotating electric machine 60 includes a rotor 61 that can rotate around a central axis J, and a stator 10. The rotor 61 faces the stator 10 in the radial direction with a gap therebetween. The rotor 61 is located radially inside the stator 10. The rotor 61 includes a shaft 62 and a rotor body 63. The shaft 62 extends in the axial direction around the central axis J. An end of the shaft 62 on one axial side (+Y side) protrudes into the gear housing 82. A reduction gear 71 is connected to an end of the shaft 62 on one axial side. The rotor body 63 is fixed to the outer peripheral surface of the shaft 62. Although not shown, the rotor body 63 includes a rotor core and a magnet.

In this embodiment, the stator 10 is located radially outside the rotor 61. The stator 10 is annular and surrounds the rotor 61. The stator 10 includes a stator core 20, a coil 30, and an insulating sheet 40.

As shown in FIG. 2, the stator core 20 is annular and surrounds the central axis J. The stator core 20 is substantially annular and centered on the central axis J. The stator core 20 is made of a magnetic material. The stator core 20 is formed, for example, by stacking a plurality of plate members in the axial direction. The plate members are, for example, electromagnetic steel plates. The stator core 20 has a core back 21 and a plurality of teeth 22. The core back 21 is annular and surrounds the central axis J. In this embodiment, the core back 21 is cylindrical and centered on the central axis J, with openings on both axial sides.

The teeth 22 extend radially inward from the core back 21. The teeth 22 are spaced apart in the circumferential direction. The teeth 22 are spaced apart around the circumference. As shown in FIG. 3, the teeth 22 have a teeth main body portion 22a and an umbrella portion 22b. The teeth main body portion 22a extends radially inward from the core back 21. The circumferential dimension of the teeth main body portion 22a decreases radially inward.

The tooth main body 22a has a side surface 22c on one circumferential side (+θ side) and a side surface 22d on the other circumferential side (-θ side). When viewed in the axial direction, the side surfaces 22c and 22d extend radially inward from the core back 21. When viewed in the axial direction, the side surfaces 22c and 22d of one tooth 22 extend in a direction approaching each other in the circumferential direction as they move radially inward. In this embodiment, the side surface 22d of one tooth 22 located on one circumferential side of a pair of circumferentially adjacent teeth 22 and the side surface 22c of the other tooth 22 located on the other circumferential side extend parallel to each other when viewed in the axial direction.

The umbrella portion 22b is connected to the radially inner end of the tooth main body portion 22a. The umbrella portion 22b protrudes on both sides in the circumferential direction beyond the radially inner end of the tooth main body portion 22a. The radially inner surface of the umbrella portion 22b is the radially inner end face of the tooth 22, and is an arc shape centered on the central axis J when viewed in the axial direction.

The stator core 20 has a slot portion 23 between each pair of teeth 22 adjacent in the circumferential direction. A plurality of slot portions 23 are provided at intervals in the circumferential direction. The plurality of slot portions 23 are arranged at equal intervals around the circumference in the circumferential direction. Each slot portion 23 is composed of a pair of teeth 22 adjacent in the circumferential direction and a portion of the core back 21 that connects the radially outer ends of the pair of teeth 22. The inner edge of the slot portion 23 is a generally rectangular shape that is long in the radial direction when viewed in the axial direction.

The slot portion 23 has an opening 23c at its radially inner end that opens radially inward. The opening 23c is provided between two circumferentially adjacent umbrella portions 22b. The circumferential dimension of the opening 23c is smaller than the circumferential dimension of the portion of the slot portion 23 that is located radially outward from the opening 23c.

As shown in FIG. 4, the inner edge of the slot portion 23 has a first connection portion 23a and a second connection portion 23b when viewed in the axial direction. The first connection portion 23a is a connection portion between the side surface 22c, which is the surface on one circumferential side (+θ side) of the tooth 22, and the inner peripheral surface 21a, which is the radially inner surface of the core back 21. The second connection portion 23b is a connection portion between the side surface 22d, which is the surface on the other circumferential side (-θ side) of the tooth 22, and the inner peripheral surface 21a, which is the radially inner surface of the core back 21. The first connection portion 23a is a corner portion on the radially outer side and the other circumferential side of the inner edge of the slot portion 23, which is approximately rectangular when viewed in the axial direction. The second connection portion 23b is a corner portion on the radially outer side and the one circumferential side of the inner edge of the slot portion 23, which is approximately rectangular when viewed in the axial direction. The first connection portion 23a and the second connection portion 23b are arranged at an interval in the circumferential direction.

In this embodiment, the first connection portion 23a and the second connection portion 23b are curved when viewed in the axial direction. Therefore, the teeth 22 and the core back 21 can be smoothly connected, and the stress generated in the teeth 22 can be appropriately distributed and received at each connection portion. The first connection portion 23a is an arc shape that is concave radially outward and toward the other circumferential side (-θ side) when viewed in the axial direction. The second connection portion 23b is an arc shape that is concave radially outward and toward one circumferential side (+θ side) when viewed in the axial direction. The radius of curvature of the first connection portion 23a and the radius of curvature of the second connection portion 23b are different from each other. In this embodiment, the radius of curvature of the first connection portion 23a is smaller than the radius of curvature of the second connection portion 23b.

When viewed in the axial direction, the first connection portion 23a and the second connection portion 23b are asymmetrical with respect to the first virtual line CL1 that passes through the circumferential center of the slot portion 23 and extends in the radial direction. In other words, when viewed in the axial direction, the first connection portion 23a and the second connection portion 23b are not symmetrical with respect to the first virtual line CL1 as an axis of symmetry. When viewed in the axial direction, the first virtual line CL1 passes through the circumferential center between the side surface 22d located on one circumferential side of the inner surface of the slot portion 23 and the side surface 22c located on the other circumferential side of the inner surface of the slot portion 23. When viewed in the axial direction, the first connection portion 23a and the second connection portion 23b are also asymmetrical with respect to the second virtual line CL2 that passes through the circumferential center of the tooth 22 and extends in the radial direction. The second virtual line CL2 passes through the circumferential center of the tooth main body portion 22a.

In this embodiment, the coil 30 is made of a rectangular wire. The coil 30 is, for example, a full-pitch wound coil. The coil 30 has a conductor portion 31 located in each slot portion 23. In other words, the stator 10 is equipped with a conductor portion 31. The conductor portion 31 extends in the axial direction within the slot portion 23. The conductor portion 31 is made of a rectangular wire. In a cross section perpendicular to the axial direction, the shape of the conductor portion 31 is a generally rectangular shape with rounded corners that is long in the circumferential direction. A plurality of conductor portions 31 are arranged radially within each slot portion 23.

Although not shown in the figure, the coil 30 has a first connecting conductor portion that connects the conductor portions 31 located in different slot portions 23 to one side of the stator core 20 in the axial direction, and a second connecting conductor portion that connects the conductor portions 31 located in different slot portions 23 to the other side of the stator core 20 in the axial direction. At least one of the first connecting conductor portion and the second connecting conductor portion is a separate member from the conductor portion 31 and is connected to the conductor portion 31 by welding.

The insulating sheet 40 is a sheet-like member made of an insulating material. There are no particular limitations on the material that makes up the insulating sheet 40, so long as it has insulating properties. In this embodiment, the insulating sheet 40 is insulating paper. The insulating sheet 40 is provided in each slot portion 23. At least a portion of the insulating sheet 40 is located between the conductor portion 31 and the stator core 20 in the slot portion 23. The insulating sheet 40 insulates the conductor portion 31 from the stator core 20. In this embodiment, the insulating sheet 40 is flexible.

In this embodiment, the insulating sheet 40 is a substantially rectangular tube wound around an axis extending in the axial direction. As shown in FIG. 3, the outer shape of the insulating sheet 40 is a substantially rectangular shape that is long in the radial direction when viewed in the axial direction. In this embodiment, the insulating sheet 40 surrounds the multiple conductors 31 in the slot portion 23. Therefore, the insulating sheet 40 can insulate the multiple conductors 31 and the stator core 20 collectively. As shown in FIG. 1, the axial dimension of the insulating sheet 40 is larger than the axial dimension of the stator core 20. The insulating sheet 40 protrudes on both sides in the axial direction beyond the stator core 20. As shown in FIG. 3, the insulating sheet 40 has a shape that extends from the first end 40a to the second end 40b when viewed in the axial direction. For example, the insulating sheet 40 is wound into a cylindrical shape and inserted into the slot portion 23 from either side in the axial direction, and is disposed in the slot portion 23.

Here, for example, the first end 40a and the like are prone to being partially worn away when they come into contact with the stator core 20 when the insulating sheet 40 is placed in the slot portion 23. In response to this, for example, a recess may be provided on the side surface of the tooth 22, and the easily worn parts of the insulating sheet 40, such as the first end 40a, may be allowed to escape into the recess, thereby preventing the insulating sheet 40 from being partially worn away. However, in this case, the tooth 22 becomes thinner in the circumferential direction by the amount of the recess, and the amount of magnetic flux flowing through the tooth 22 decreases. This causes a problem of a decrease in the torque of the rotating electric machine 60.

In contrast, according to the present embodiment, the first connection portion 23a between the side surface 22c on one circumferential side of the tooth 22 and the inner circumferential surface 21a of the core back 21, and the second connection portion 23b between the side surface 22d on the other circumferential side of the tooth 22 and the inner circumferential surface 21a of the core back 21 are asymmetrical with respect to each other across the first virtual line CL1 that passes through the circumferential center of the slot portion 23 and extends in the radial direction, as viewed in the axial direction. Therefore, it is possible to form the first connection portion 23a and the second connection portion 23b into shapes that correspond to different purposes. Specifically, it is possible to form the first connection portion 23a into a shape that easily prevents contact between the parts of the insulating sheet 40 that are easily scraped, while forming the second connection portion 23b into a shape that easily increases the amount of magnetic flux flowing through the tooth 22. As a result, by arranging the part of the insulating sheet 40 that is easily scraped off when it comes into contact with the stator core 20 near the first connection portion 23a, it is possible to prevent a part of the insulating sheet 40 from coming into contact with the stator core 20 and being scraped off without providing a recess on the side surfaces 22c, 22d of the teeth 22. As a result, since it is not necessary to provide a recess, the amount of magnetic flux flowing through the teeth 22 is not reduced due to the recess. In addition, by making the second connection portion 23b into a shape that makes it easy to increase the amount of magnetic flux flowing through the teeth 22, even if the first connection portion 23a has a shape that makes it difficult for magnetic flux to flow in order to avoid contact with the insulating sheet 40, it is possible to prevent a reduction in the amount of magnetic flux flowing through the teeth 22. As described above, according to this embodiment, it is possible to prevent a part of the insulating sheet 40 from being scraped off when the insulating sheet 40 is arranged in the slot portion 23, while preventing a decrease in the torque of the rotating electric machine 60. In addition, since it is possible to prevent a part of the insulating sheet 40 from being scraped off, it is possible to prevent the part scraped off from the insulating sheet 40 from remaining as a foreign object in the rotating electric machine 60.

In addition, according to this embodiment, the first connection portion 23a and the second connection portion 23b are curved when viewed in the axial direction. The radius of curvature of the first connection portion 23a and the radius of curvature of the second connection portion 23b are different from each other. Therefore, it is possible to increase the radius of curvature of the second connection portion 23b while decreasing the radius of curvature of the first connection portion 23a. By decreasing the radius of curvature of the first connection portion 23a, it is possible to suppress the first connection portion 23a from protruding toward the slot portion 23. Therefore, by arranging the easily scraped portion of the insulating sheet 40 near the first connection portion 23a, it is possible to further suppress the easily scraped portion of the insulating sheet 40 from contacting the stator core 20 when the insulating sheet 40 is arranged in the slot portion 23. In addition, by increasing the radius of curvature of the second connection portion 23b, it is possible to cause the second connection portion 23b to protrude into the slot portion 23. Therefore, the circumferential dimension of the teeth 22 can be increased at the second connection portion 23b, and the amount of magnetic flux flowing through the teeth 22 can be increased. Therefore, when the insulating sheet 40 is placed in the slot portion 23, it is possible to prevent a portion of the insulating sheet 40 from being scraped off, and to prevent a decrease in the torque of the rotating electric machine 60.

In this embodiment, the first end 40a and the second end 40b are located radially between the conductor portion 31 and the core back 21. The first end 40a is located radially outward of the second end 40b. The first end 40a is in contact with the inner peripheral surface 21a of the core back 21. As shown in FIG. 4, the first end 40a is located on the other circumferential side (-θ side) of the first virtual line CL1. The second end 40b is located on one circumferential side (+θ side) of the first virtual line CL1.

As shown in FIG. 3, the insulating sheet 40 has a first circumferential extension portion 41a, a first radial extension portion 42a, a second circumferential extension portion 41b, a second radial extension portion 42b, and a third circumferential extension portion 41c.

The first circumferential extension portion 41a extends in the circumferential direction. The first circumferential extension portion 41a is located radially between the conductor portion 31 and the core back 21. The end portion on the other circumferential side (-θ side) of the first circumferential extension portion 41a is the first end portion 40a. As shown in FIG. 4, the end portion on the other circumferential side of the first circumferential extension portion 41a, i.e., the first end portion 40a, is located on one circumferential side (+θ side) of the first connection portion 23a. Here, as described above, the first end portion 40a is a part of the insulating sheet 40 that is easily scraped, and the radius of curvature of the first connection portion 23a is smaller than the radius of curvature of the second connection portion 23b. Therefore, by arranging the first end 40a, which is easily scraped, on one circumferential side of the first connection portion 23a, which has a relatively small radius of curvature and is prevented from protruding into the slot portion 23, it is possible to prevent the first end 40a from coming into contact with the stator core 20 when placing the insulating sheet 40 in the slot portion 23. This makes it possible to further prevent a portion of the insulating sheet 40 from being scraped off when placing the insulating sheet 40 in the slot portion 23.

In this embodiment, the first end 40a is arranged to face the first connection portion 23a in the circumferential direction with a small gap therebetween. In this embodiment, the first end 40a is located at the end on the other circumferential side (-θ side) in the slot portion 23. The first end 40a is located on one circumferential side (+θ side) of the surface on the other circumferential side of the conductor portion 31. The first end 40a may be located at the same position in the circumferential direction as the surface on the other circumferential side of the conductor portion 31, or may be located on the other circumferential side of the surface on the other circumferential side of the conductor portion 31. The first circumferential extension portion 41a is in contact with the inner peripheral surface 21a of the core back 21. In this embodiment, the end on one circumferential side of the first circumferential extension portion 41a is in contact with the second connection portion 23b.

The first radial extension portion 42a extends radially inward from the end of the first circumferential extension portion 41a on one circumferential side (+θ side). The first radial extension portion 42a is located between the side surface 22d on the other circumferential side (-θ side) of the tooth 22 and the conductor portion 31 in the circumferential direction. In this embodiment, the first radial extension portion 42a is located between the side surface 22d and the multiple conductor portions 31 arranged in the slot portion 23 in the circumferential direction. The first radial extension portion 42a is in contact with the surface on one circumferential side of each conductor portion 31 and the side surface 22d. The radially outer end of the first radial extension portion 42a is in contact with the second connection portion 23b. The connection portion 43 between the first circumferential extension portion 41a and the first radial extension portion 42a is in an arc shape along the second connection portion 23b when viewed in the axial direction, and is in contact with the second connection portion 23b.

As shown in FIG. 3, the radially inner end of the first radial extension portion 42a is located radially outward of the portion of the umbrella portion 22b that protrudes toward the other circumferential side (-θ side) from the tooth main body portion 22a. The radially inner end of the first radial extension portion 42a faces the umbrella portion 22b in the radial direction with a gap therebetween. The umbrella portion 22b that the first radial extension portion 42a faces radially is the umbrella portion 22b of the tooth 22 that has the side surface 22d with which the first radial extension portion 42a contacts.

The second circumferential extension portion 41b extends from the radially inner end of the first radial extension portion 42a to the other circumferential side (-θ side). The second circumferential extension portion 41b is located radially inside the multiple conductor portions 31. The second circumferential extension portion 41b is in contact with, for example, the radially inner surface of the conductor portion 31 that is located radially innermost among the multiple conductor portions 31. The second circumferential extension portion 41b is positioned facing the opening 23c with a gap therebetween on the radially outer side.

The second radial extension portion 42b extends radially outward from the end of the second circumferential extension portion 41b on the other circumferential side (-θ side). The second radial extension portion 42b is located circumferentially between the side surface 22c on one circumferential side (+θ side) of the tooth 22 and the conductor portion 31. In this embodiment, the second radial extension portion 42b is located circumferentially between the side surface 22c and the multiple conductor portions 31 arranged in the slot portion 23. The second radial extension portion 42b is in contact with the other circumferential side surface of each conductor portion 31 and the side surface 22c.

The radially inner end of the second radial extension portion 42b is located radially outside the portion of the umbrella portion 22b that protrudes toward one circumferential side (+θ side) from the tooth main body portion 22a. The radially inner end of the second radial extension portion 42b faces the umbrella portion 22b in the radial direction via a gap. The umbrella portion 22b that the second radial extension portion 42b faces radially is the umbrella portion 22b of the tooth 22 having the side surface 22c with which the second radial extension portion 42b contacts. As shown in FIG. 4, the radially outer end of the second radial extension portion 42b is located radially inside the first connection portion 23a. The radially outer end of the second radial extension portion 42b faces the first connection portion 23a via a gap.

The third circumferential extension portion 41c extends from the radially outer end of the second radial extension portion 42b to one circumferential side (+θ side). At least a portion of the third circumferential extension portion 41c is located radially between the first circumferential extension portion 41a and the conductor portion 31. In this embodiment, the entire third circumferential extension portion 41c, except for the end on the other circumferential side (-θ side), is located radially between the first circumferential extension portion 41a and the conductor portion 31. The third circumferential extension portion 41c is in contact with the radially inner surface of the first circumferential extension portion 41a and the radially outer surface of the conductor portion 31 that is located radially outermost among the multiple conductor portions 31. The surface of the conductor 31 with which the third circumferential extension 41c comes into contact is a flat surface 31a that radially sandwiches the first circumferential extension 41a and the third circumferential extension 41c between the inner peripheral surface 21a, which is the radially inner surface of the core back 21. In other words, the conductor 31 disposed on the outermost radial side in the slot 23 has a flat surface 31a. The flat surface 31a is a flat surface that is perpendicular to the first virtual line CL1.

The end on one circumferential side (+θ side) of the third circumferential extension portion 41c is the second end portion 40b. The end on one circumferential side of the third circumferential extension portion 41c, i.e., the second end portion 40b, is located on the other circumferential side (-θ side) of the connection portion 43 between the first circumferential extension portion 41a and the first radial extension portion 42a. In this embodiment, the second end portion 40b is positioned circumferentially opposite the connection portion 43 with a small gap between them.

Here, like the first end 40a, the second end 40b is easily scraped off if it comes into contact with the stator core 20 when the insulating sheet 40 is placed in the slot portion 23. However, in this embodiment, the second end 40b is an end on one circumferential side (+θ side) of the third circumferential extension portion 41c located radially inside the first circumferential extension portion 41a. Therefore, the second end 40b is located inside the insulating sheet 40 folded into a cylindrical shape, and is not exposed to the outside of the cylindrical insulating sheet 40. This makes it possible to prevent the second end 40b from coming into contact with the stator core 20 when the insulating sheet 40 is placed in the slot portion 23. Therefore, it is possible to further prevent a part of the insulating sheet 40 from being scraped off when the insulating sheet 40 is placed in the slot portion 23.

The end of the third circumferential extension 41c on one circumferential side (+θ side) is the second end 40b, and is located on the other circumferential side (−θ side) of the connection portion 43. That is, in this embodiment, the insulating sheet 40 does not have any other part connected to the end of the third circumferential extension 41c on one circumferential side. Therefore, the part where the parts of the insulating sheet 40 folded into a cylindrical shape are overlapped can be only the part where the first circumferential extension 41a and the third circumferential extension 41c are overlapped in the radial direction. As a result, the space in the slot 23 in which the conductor 31 can be arranged can be made larger in the circumferential direction, compared to the case where, for example, a part where the parts of the insulating sheet 40 are overlapped in the circumferential direction is provided between the teeth 22 and the conductor 31. Therefore, the circumferential dimension of the conductor 31 can be increased, and the current flowing through the coil 30 can be suitably increased. Therefore, the torque of the rotating electric machine 60 can be improved without increasing the size of the rotating electric machine 60.

In addition, for example, if the portion where the first circumferential extension portion 41a and the third circumferential extension portion 41c overlap in the radial direction is positioned opposite the opening 23c of the slot portion 23, there is a risk that the first circumferential extension portion 41a will separate from the third circumferential extension portion 41c during assembly of the stator 10, causing the first end portion 40a and the like to protrude from the opening 23c to the outside of the slot portion 23. Therefore, in this case, it may be difficult to assemble the stator 10.

In contrast, according to the present embodiment, the portion where the first circumferential extension portion 41a and the third circumferential extension portion 41c overlap in the radial direction is disposed between the conductor portion 31 and the core back 21 in the radial direction. Therefore, the core back 21 can prevent the first circumferential extension portion 41a from moving radially away from the third circumferential extension portion 41c. Therefore, when assembling the stator 10, the first circumferential extension portion 41a can be prevented from moving away from the third circumferential extension portion 41c, and the stator 10 can be prevented from becoming difficult to assemble. In addition, after assembling the stator 10, the portion where the first circumferential extension portion 41a and the third circumferential extension portion 41c overlap can be sandwiched and pressed by the conductor portion 31 and the core back 21. This allows the insulating sheet 40 to be appropriately held in the slot portion 23.

In addition, according to this embodiment, as described above, the conductor portion 31 arranged radially outward in the slot portion 23 has a flat portion 31a that radially sandwiches the first circumferential extension portion 41a and the third circumferential extension portion 41c between the flat portion 31a and the inner peripheral surface 21a of the core back 21. Therefore, the flat portion 31a can preferably press the first circumferential extension portion 41a and the third circumferential extension portion 41c against the core back 21. Therefore, the insulating sheet 40 can be more preferably held in the slot portion 23.

Here, a small gap may be formed between the first circumferential extension portion 41a and the third circumferential extension portion 41c in the radial direction. In this case, if a relatively large current flows through the conductor portion 31, the current may flow from the conductor portion 31 to the gap. The current flowing through the gap may flow from the portion of the gap between the second end portion 40b and the first circumferential extension portion 41a to the other circumferential side (-θ side) and flow from the portion of the gap between the first end portion 40a and the third circumferential extension portion 41c to the stator core 20. Therefore, in order to further improve the insulation between the conductor portion 31 and the stator core 20 by the insulating sheet 40, it is preferable to increase the circumferential dimension of the portion where the first circumferential extension portion 41a and the third circumferential extension portion 41c are overlapped, and to increase the creepage distance between the conductor portion 31 and the stator core 20.

In contrast, according to this embodiment, as described above, the first end 40a is located on the other circumferential side (-θ side) of the first imaginary line CL1, and the second end 40b is located on one circumferential side (+θ side) of the first imaginary line CL1. This makes it possible to suitably increase the circumferential dimension of the portion where the first circumferential extension portion 41a and the third circumferential extension portion 41c overlap in the radial direction. This makes it possible to suitably increase the creepage distance between the conductor portion 31 and the stator core 20. This makes it possible to suitably suppress the flow of current from the conductor portion 31 to the stator core 20.

In addition, according to this embodiment, the first end 40a is located at the end on the other circumferential side (-θ side) within the slot portion 23. Therefore, the circumferential dimension of the portion where the first circumferential extension portion 41a and the third circumferential extension portion 41c overlap in the radial direction can be more suitably increased. This makes it possible to more suitably increase the creepage distance between the conductor portion 31 and the stator core 20. Therefore, it is possible to more suitably suppress the flow of current from the conductor portion 31 to the stator core 20.

When the first end 40a is disposed at the end on the other circumferential side (-θ side) in the slot portion 23, the first end 40a approaches the first connection portion 23a, but as described above, the first connection portion 23a is shaped to make it difficult for it to come into contact with the first end 40a. Therefore, even if the first end 40a is disposed at the end on the other circumferential side in the slot portion 23, it is possible to prevent the first end 40a from coming into contact with the stator core 20 when the insulating sheet 40 is disposed in the slot portion 23.

As described above, in this embodiment, by limiting the overlapping portions of the insulating sheet 40 to the portions located radially outward of the insulating sheet 40, the circumferential size of the space in which the conductor portion 31 is disposed in the slot portion 23 can be suitably secured, and the overlapping portions of the insulating sheet 40 can be prevented from coming apart. Furthermore, by arranging the first end 40a at the end on the other circumferential side (-θ side) in the slot portion 23, the circumferential size of the overlapping portions can be increased, and the creepage distance between the conductor portion 31 and the stator core 20 can be increased. With these configurations, the conductor portion 31 can be enlarged to increase the amount of current that can flow through the coil 30, while making it easier to assemble the stator 10, and the insulating sheet 40 can suitably insulate the conductor portion 31 from the stator core 20. In addition, even if the insulating sheet 40 is arranged in the slot portion 23 in such a manner that these effects can be obtained, by reducing the radius of curvature of the first connection portion 23a to which the first end portion 40a faces, it is possible to prevent the first end portion 40a from contacting the first connection portion 23a when the insulating sheet 40 is arranged in the slot portion 23. Furthermore, by increasing the radius of curvature of the second connection portion 23b, which does not need to allow the first end portion 40a to escape, the teeth 22 can be enlarged in the circumferential direction at the second connection portion 23b, and the amount of magnetic flux flowing through the teeth 22 can be increased. As described above, according to this embodiment, the conductor portion 31 and the stator core 20 are suitably insulated by the insulating sheet 40, while the assembly of the stator 10 can be facilitated and the torque of the rotating electric machine 60 can be suitably improved.

In this embodiment, the worker who assembles the stator 10 inserts the insulating sheet 40, which is folded into a cylindrical shape by overlapping parts of it, into each slot 23 of the stator core 20 from either side in the axial direction. At this time, the worker inserts the insulating sheet 40 into the slot 23 with the overlapped parts of the insulating sheet 40 facing radially outward. The overlapped parts are the parts where the first circumferential extension part 41a and the third circumferential extension part 41c are overlapped in the radial direction. In this embodiment, the insulating sheet 40 is flexible, so that the insulating sheet 40 folded into a cylindrical shape is in an elastically deformed state. As a result, the insulating sheet 40 inserted into the slot 23 in a cylindrical state is pressed against the inner surface of the slot 23 in an attempt to restore its original shape and is held in the slot 23.

The worker inserts a plurality of conductor parts 31 in the axial direction into each of the inner sides of the cylindrical insulating sheets 40 inserted into the slots 23. After inserting the conductor parts 31 into the slots 23, the worker welds at least one of the ends on both axial sides of the conductor parts 31 to the first connection conductor part or the second connection conductor part not shown in the figure. If one of the first connection conductor part and the second connection conductor part is integrally molded with the conductor part 31, the worker welds only the other of the first connection conductor part and the second connection conductor part to the conductor part 31. On the other hand, if both the first connection conductor part and the second connection conductor part are separate from the conductor part 31, the worker welds both the first connection conductor part and the second connection conductor part to the conductor part 31. In this manner, the stator 10 is assembled.

In this specification, "workers, etc." includes workers who perform each task and assembly equipment, etc. Each task may be performed by a worker alone, by an assembly device alone, or by both a worker and an assembly device.

Below, an embodiment different from the first embodiment described above will be described. In the description of the following embodiments, the description of the same configuration as the first embodiment described above may be omitted by, for example, appropriately assigning the same reference numerals. Furthermore, as the configuration whose description is omitted in the following embodiments, the same configuration as the first embodiment described above may be adopted within a range that does not cause inconsistency.

Second Embodiment
As shown in FIG. 5, in the slot portion 223 of the stator core 220 of this embodiment, the first connection portion 223a is angular when viewed in the axial direction. In other words, the first connection portion 223a is pin-angled when viewed in the axial direction. More specifically, the first connection portion 223a is angular at approximately 90° when viewed in the axial direction. The first connection portion 223a is formed by connecting the side surface 22c of the tooth 22 and the inner peripheral surface 21a of the core back 21 at approximately a right angle. When the first connection portion 223a has such a shape, it is possible to more effectively prevent the first connection portion 223a from protruding into the slot portion 223. Therefore, when the insulating sheet 40 is disposed in the slot portion 223, it is possible to more effectively prevent the first end portion 40a of the insulating sheet 40 from contacting the first connection portion 223a.

The present invention is not limited to the above-described embodiment, and other configurations and methods may be adopted within the scope of the technical concept of the present invention. The first and second connection parts provided on the inner edge of the slot may have any shape as long as they are asymmetrical with respect to an imaginary line that passes through the circumferential center of the slot and extends radially, as viewed in the axial direction. For example, the first and second connection parts may be in the form of broken lines, as viewed in the axial direction. The number of conductor parts arranged in the slot is not particularly limited, as long as it is one or more. The conductor part may be made of a round wire. The coil may have any configuration as long as it has at least one conductor part.

The insulating sheet may have any shape as long as at least a portion of the insulating sheet is located between the conductor portion and the stator core within the slot portion. The first end and second end of the insulating sheet may be arranged in any manner. If the insulating sheet has portions where parts are overlapped, the overlapped portions may be located anywhere within the slot portion. The insulating sheet does not have to have portions where parts are overlapped.

At least a portion of the area where the insulating sheet 40 and the stator core 20 were in contact with each other in the first embodiment described above may not be in contact with each other. At least a portion of the area where the insulating sheet 40 and the conductor portion 31 were in contact with each other in the first embodiment described above may not be in contact with each other. In the first embodiment described above, the insulating sheet 40 may be in contact with the umbrella portion 22b.

The rotating electric machine to which the present invention is applied may be an outer rotor type rotating electric machine. In this case, the radially outer side corresponds to the "one radial side" and the radially inner side corresponds to the "other radial side". The rotating electric machine is not limited to a motor, and may be a generator. The use of the rotating electric machine is not particularly limited. The rotating electric machine may be mounted on equipment other than a vehicle. The use of the drive unit to which the present invention is applied is not particularly limited. For example, the drive unit may be mounted on a vehicle for an application other than rotating an axle, or may be mounted on equipment other than a vehicle. The attitude of the rotating electric machine and the drive unit when used is not particularly limited. The central axis of the rotating electric machine may be inclined with respect to a horizontal direction perpendicular to the vertical direction, or may extend in the vertical direction.

The present technology can be configured as follows.
(1) A stator core having an annular core back surrounding a central axis, and a plurality of teeth extending radially from the core back to one side and spaced apart in the circumferential direction, with a slot portion provided between each of the circumferentially adjacent teeth, a conductor portion located within the slot portion, and an insulating sheet having at least a portion located within the slot portion between the conductor portion and the stator core, wherein, as viewed in the axial direction, an inner edge of the slot portion has a first connection portion which is a connection portion between a surface of the tooth on one circumferential side and a surface of the core back on one radial side, and a second connection portion which is a connection portion between a surface of the tooth on the other circumferential side and a surface of the core back on one radial side, the first connection portion and the second connection portion having asymmetric shapes relative to each other across an imaginary line which passes through a circumferential center of the slot portion and extends radially, as viewed in the axial direction.
(2) The stator according to (1), wherein the first connection portion and the second connection portion are curved when viewed in the axial direction, and a radius of curvature of the first connection portion and a radius of curvature of the second connection portion are different from each other.
(3) The stator described in (2), wherein the insulating sheet has a shape extending from a first end to a second end when viewed in the axial direction and has a first circumferential extending portion and a first radial extending portion, the first circumferential extending portion extends in a circumferential direction and is located radially between the conductor portion and the core back, the first radial extending portion extends from an end portion on one circumferential side of the first circumferential extending portion to one radial side and is located circumferentially between a surface of the tooth on the other circumferential side and the conductor portion, the end portion on the other circumferential side of the first circumferential extending portion is the first end and is located on one circumferential side of the first connection portion, and a radius of curvature of the first connection portion is smaller than a radius of curvature of the second connection portion.
(4) The stator described in (3), wherein the insulating sheet has a second circumferential extension portion extending from an end portion on one radial side of the first radial extension portion to the other circumferential side, a second radial extension portion extending from an end portion on the other circumferential side of the second circumferential extension portion to the other radial side and positioned circumferentially between a surface of the tooth on one circumferential side and the conductor portion, and a third circumferential extension portion extending from an end portion on the other radial side of the second radial extension portion to one circumferential side and at least a portion of which is positioned radially between the first circumferential extension portion and the conductor portion, and the end portion on the one circumferential side of the third circumferential extension portion is the second end and is positioned on the other circumferential side of a connection portion between the first circumferential extension portion and the first radial extension portion.
(5) The stator according to (4), in which the first end portion is located on the other circumferential side of the imaginary line, and the second end portion is located on one circumferential side of the imaginary line.
(6) The stator according to (5), wherein the first end portion is located at an end portion on the other circumferential side within the slot portion.
(7) The stator according to any one of (4) to (6), wherein the conductor portion extends in the axial direction, a plurality of the conductor portions are arranged in the slot portion in a radial direction, and the insulating sheet surrounds the plurality of conductor portions in the slot portion when viewed in the axial direction.
(8) The stator described in (7), wherein the conductor portion is formed of a rectangular wire, and the conductor portion arranged on the other radial side in the slot portion has a flat portion that radially sandwiches the first circumferential extension portion and the third circumferential extension portion between itself and a surface on one radial side of the core back.
(9) A rotating electric machine comprising: the stator according to any one of (1) to (8); and a rotor facing the stator with a radial gap therebetween.
(10) A drive device comprising: the rotating electric machine according to (9) above; and a gear mechanism connected to the rotating electric machine.

The configurations described above in this specification can be combined as appropriate within the scope of not mutually contradicting each other.

10... stator, 20, 220... stator core, 21... core back, 22... teeth, 23, 223... slot portion, 23a, 223a... first connection portion, 23b... second connection portion, 31... conductor portion, 31a... flat portion, 40... insulating sheet, 40a... first end portion, 40b... second end portion, 41a... first circumferential extension portion, 41b... second circumferential extension portion, 41c... third circumferential extension portion, 42a... first radial extension portion, 42b... second radial extension portion, 43... connection portion, 60... rotating electric machine, 61... rotor, 70... gear mechanism, 100... drive unit, CL1... first virtual line (virtual line), J... center axis

Claims (10)

a stator core having an annular core back surrounding a central axis, and a plurality of teeth extending from the core back to one radial side and arranged at intervals in a circumferential direction, with a slot portion provided between each of the teeth adjacent to each other in the circumferential direction;
A conductor portion located within the slot portion;
an insulating sheet, at least a portion of which is located within the slot between the conductor portion and the stator core;
Equipped with
When viewed in the axial direction, an inner edge of the slot portion has a first connection portion which is a connection portion between one circumferential side surface of the tooth and one radial side surface of the core back, and a second connection portion which is a connection portion between the other circumferential side surface of the tooth and one radial side surface of the core back,
A stator in which the first connection portion and the second connection portion have asymmetric shapes when viewed in the axial direction, with respect to an imaginary line that passes through a circumferential center of the slot portion and extends in a radial direction. the first connection portion and the second connection portion are curved when viewed in the axial direction,
The stator according to claim 1 , wherein a radius of curvature of the first connection portion and a radius of curvature of the second connection portion are different from each other. the insulating sheet has a shape extending from a first end to a second end when viewed in the axial direction, and has a first circumferential extending portion and a first radial extending portion;
the first circumferential extension portion extends in a circumferential direction and is located between the conductor portion and the core back in a radial direction,
the first radially extending portion extends from one circumferential end of the first circumferentially extending portion to one radial side and is located circumferentially between a surface of the tooth on the other circumferential side and the conductor portion;
an end portion on the other circumferential side of the first circumferential extension portion is the first end portion and is located on one circumferential side of the first connection portion;
The stator according to claim 2 , wherein a radius of curvature of the first connection portion is smaller than a radius of curvature of the second connection portion. The insulating sheet is
a second circumferentially extending portion extending from a radially one end of the first radially extending portion to a circumferentially other end;
a second radially extending portion extending from an end portion on the other circumferential side of the second circumferential extending portion to the other radial side and positioned circumferentially between a surface on one circumferential side of the tooth and the conductor portion;
a third circumferential extending portion extending from an end portion on the other radial side of the second radial extending portion to one circumferential side, and at least a portion of the third circumferential extending portion being located radially between the first circumferential extending portion and the conductor portion;
having
4. The stator according to claim 3, wherein an end portion on one circumferential side of the third circumferential extending portion is the second end portion and is located on the other circumferential side of a connection portion between the first circumferential extending portion and the first radially extending portion. The first end portion is located on the other circumferential side of the imaginary line,
The stator according to claim 4 , wherein the second end portion is located on one circumferential side of the imaginary line. The stator according to claim 5, wherein the first end is located at the other circumferential end of the slot portion. The conductor portion extends in an axial direction,
A plurality of the conductor portions are arranged in the slot portion in a radial direction,
The stator according to claim 4 , wherein the insulating sheet surrounds the plurality of conductor portions within the slot portion when viewed in the axial direction. The conductor portion is formed of a rectangular wire,
8. The stator according to claim 7, wherein the conductor portion arranged on the other radial side in the slot portion has a flat portion that radially sandwiches the first circumferential extension portion and the third circumferential extension portion between itself and a surface on one radial side of the core back. A stator according to any one of claims 1 to 8;
a rotor facing the stator with a gap therebetween in a radial direction;
A rotating electric machine comprising: A rotating electric machine according to claim 9 ;
a gear mechanism connected to the rotating electric machine;
A drive device comprising:

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