WO2024069695A1

WO2024069695A1 - Stator for rotary electric machine

Info

Publication number: WO2024069695A1
Application number: PCT/JP2022/035696
Authority: WO
Inventors: 洋三廣瀬
Original assignee: 日産自動車株式会社
Priority date: 2022-09-26
Filing date: 2022-09-26
Publication date: 2024-04-04

Abstract

This stator for a rotary electric machine is equipped with: a stator core which has a slot; and a flat wire coil which comprises segment coils, passes through the slot, and projects from the end surface of the stator core in the axial direction. An end section of one segment coil and an end section of another segment coil form a welded section. The one segment coil and the other segment coil are positioned in a state in which the segment coil thickness direction inside the slot and in the welded section aligns with the radial direction, and have, in the interval from the end-surface side of the stator core to the welded section side, a radial-direction curving section which curves toward the radial-direction side, a peripheral-direction extending section which is adjacent to the radial-direction curving section and extends toward the peripheral-direction side, and an axial-direction curving section which is adjacent to the peripheral-direction extending section and curves toward the axial-direction side, but do not have an edge-wise curving section.

Description

Stator of rotating electrical machine

The present invention relates to a stator for a rotating electric machine, and more specifically, to a stator for a rotating electric machine that can suppress or prevent damage to a rectangular wire coil.

　Conventionally, a rectangular wire forming device has been proposed that can perform processes such as edgewise bending on rectangular wire and can also improve the forming accuracy of rectangular wire (see Patent Document 1).

Japanese Patent No. 6848818

However, when edgewise bending a segment coil using a rectangular wire forming device such as that described in Patent Document 1 to wind a rectangular wire coil around the stator of a rotating electrical machine, the distance between the processed parts of the segment coil is so close that it is not possible to secure space to place the holding jig of the rectangular wire forming device. This causes the segment coil to fall over and come into contact with another segment coil, which can cause the rectangular wire coil to be damaged.

The present invention was made in consideration of the problems with the conventional technology, and aims to provide a stator for a rotating electrical machine that can suppress or prevent damage to the rectangular wire coil.

As a result of extensive research into achieving the above objective, the inventors discovered that the above objective could be achieved by having one segment coil and the other segment coil of the rectangular wire coil have, as they move from the end face side of the stator core to the welded portion, a radial bent portion bent radially, a circumferential extension portion extending circumferentially adjacent to the radial bent portion, and an axial bent portion bent axially adjacent to the circumferential extension portion, without having any edgewise bent portions, and thus completing the present invention.

In other words, the stator of the rotating electric machine of the present invention comprises a circular stator core having a plurality of slots in the circumferential direction, and a plurality of rectangular wire segment coils wound around the stator core, the segment coils passing through the slots and protruding axially from the end face of the stator core.
An end of one segment coil of the rectangular wire coil and an end of another segment coil are welded together outside the slot to form a welded joint.
One segment coil and another segment coil are arranged in the slot and at the welded portion with the thickness direction of the segment coil aligned in the radial direction.
As one segment coil and the other segment coil transition from the end face side of the stator core to the welded portion side, they have a radial bent portion bent radially, a circumferential extending portion extending circumferentially adjacent to the radial bent portion, and an axial bent portion bent axially adjacent to the circumferential extending portion, and do not have any edgewise bent portions.

According to the present invention, one segment coil and the other segment coil of the flat wire coil have a radial bend portion bent radially while moving from the end face side of the stator core to the welded portion side, a circumferential extension portion extending circumferentially adjacent to the radial bend portion, and an axial bend portion bent axially adjacent to the circumferential extension portion, and do not have any edgewise bent portions, so that a rotating electric stator can be provided that can suppress or prevent damage to the flat wire coil.

1 is a perspective view showing a schematic diagram of a stator for a rotating electric machine according to a first embodiment of the present invention; 2 is an explanatory diagram illustrating a schematic view of a portion of a stator of the rotating electric machine illustrated in FIG. 1 . FIG. 11 is an explanatory diagram illustrating a part of a rectangular wire coil in a stator of a rotating electric machine according to a second embodiment. FIG. 13 is an explanatory diagram illustrating a part of an example of a rectangular wire coil in a stator of a rotating electric machine according to a third embodiment. 13 is an explanatory diagram illustrating a part of another example of a rectangular wire coil in a stator of a rotating electric machine according to the third embodiment; FIG. FIG. 13 is an explanatory diagram illustrating a part of a rectangular wire coil in a stator of a rotating electric machine according to a fourth embodiment. FIG. 13 is an explanatory diagram illustrating a part of a rectangular wire coil in a stator of a rotating electric machine according to a fifth embodiment. FIG. 13 is an explanatory diagram illustrating a part of a rectangular wire coil in a stator of a rotating electric machine according to a sixth embodiment. FIG. 13 is a cross-sectional view showing a schematic view of a part of a rectangular wire coil in a stator of a rotating electric machine according to a seventh embodiment. 4 is an explanatory diagram showing a state in which a rectangular wire coil is formed in the stator of the rotating electric machine shown in FIG. 3 . FIG.

The stator of the rotating electric machine of the present invention will be described in detail below with reference to the drawings. Note that the dimensional ratios of the drawings cited below are exaggerated for the convenience of explanation and may differ from the actual ratios. In addition, in the present invention, the "circumferential direction", "axial direction" and "radial direction" respectively mean the circumferential direction, axial direction and radial direction of the annular stator core. Furthermore, in the present invention, the "inner diameter side" and "outer diameter side" respectively mean the inner diameter side (inner peripheral surface side) and outer diameter side (outer peripheral surface side) of the annular stator core.

First Embodiment
Fig. 1 is a perspective view of the stator of the rotating electric machine of this embodiment, as seen from the side where the segment coil is inserted. Fig. 2 is a front view, as seen from the outer diameter side, of a part of the welding side of the segment coils stacked at the fifth and sixth positions from the inner diameter side in the stator of the rotating electric machine shown in Fig. 1. Note that in Fig. 2, for convenience of explanation, the segment coils stacked at the first to fourth positions from the inner diameter side are omitted.

As shown in FIG. 1, the stator 1 of the rotating electric machine of this embodiment includes a stator core 10 and a rectangular wire coil 20 wound around the stator core 10.

Here, the stator core 10 is annular and has multiple slots 10a in the circumferential direction of the stator core 10. For example, an integrated stator core formed by stacking multiple annular electromagnetic steel plates in the axial direction of the stator core 10 can be used as such a stator core 10. In the illustrated example, there are 48 slots.

Furthermore, the flat wire coil 20 is composed of a plurality of segment coils 21, and has a plurality of phases of

flat wire coils

20A, 20B, 20C, which penetrate the slots 10a and protrude from the end face 10b of the welding side of the stator core 10 and the end face 10c of the insertion side in the axial direction of the stator core 10. As such a flat wire coil 20, for example, it is preferable to use a U-shaped flat wire coil having an insulating coating (not shown) other than the end 21a that forms the welding portion 21b described in detail later. Furthermore, from the viewpoint of reducing current loss, the flat wire coil 20 is preferable as the aspect ratio (coil width/coil thickness) of the flat wire coil is larger. On the other hand, the larger the aspect ratio and the longer the coil, the easier it is to bend under its own weight, in other words, it becomes unable to stand on its own. There is such a trade-off relationship in the aspect ratio of the flat wire coil. Further consideration of the trade-off relationship revealed that, from the standpoint of ease of flatwise bending and ensuring coil quality, the aspect ratio (coil width/coil thickness) of the rectangular wire coil 20 is preferably 2 or more, more preferably 3 or more, even more preferably 5 or more, and preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. Note that the illustrated example is a three-phase type, and these phases are called the U phase, V phase, and W phase.

As shown in Figure 2, the end 21a of one segment coil 21α of the rectangular wire coil 20 is welded to the end 21a of the other segment coil 21β outside the slot 10a (see Figure 1) to form a welded portion 21b. In this embodiment, as shown in Figures 1 and 2, the end 21a of one segment coil 21 of the rectangular wire coil 20 is welded to the end 21a of another segment coil 21 outside the slot 10a to form a welded portion 21b.

Furthermore, one segment coil 21α and the other segment coil 21β are arranged in the slot 10a and the welded portion 21b with the thickness direction of the segment coils 21α and 21β aligned along the radial direction of the stator core 10. Note that the thickness direction of the segment coils 21α and 21β and the radial direction of the stator core 10 are perpendicular to the paper (front and back) in the center of FIG. 2, and are approximately perpendicular to the paper (front and back) on the right and left sides of FIG. 2.

Furthermore, one segment coil 21α and the other segment coil 21β have a radial bent portion 211, a circumferential extension portion 213, and an axial bent portion 215 while transitioning from the end face 10b side of the stator core 10 to the welded portion 21b side, and do not have any edgewise bent portions.

Here, the radially bent portion 211 is bent flatwise toward the radial side. The circumferentially extending portion 213 extends toward the circumferential side adjacent to the radially bent portion 211. The axially bent portion 215 is bent flatwise toward the axial side adjacent to the circumferentially extending portion 213.

The radial, circumferential, and axial sides of one segment coil 21α, which is stacked in the sixth (even-numbered) position from the inner diameter side in the radial direction, are the outer diameter side (the front side of the paper in FIG. 2), the counterclockwise direction when looking at the welded portion 21b from the axial direction (the right side in FIG. 2), and the axial direction (the upper side in FIG. 2), respectively. The radial, circumferential, and axial sides of another segment coil 21β, which is stacked in the fifth (odd-numbered) position from the inner diameter side in the radial direction, are the outer diameter side (the front side of the paper in FIG. 2), the clockwise direction when looking at the welded portion 21b from the axial direction (the left side in FIG. 2), and the axial direction (the upper side in FIG. 2), respectively.

Next, the advantages of this embodiment will be explained. According to the stator 1 of the rotating electric machine of this embodiment, the flat wire coil has the above-mentioned radial bent portion 211, circumferential extension portion 213, and axial bent portion 215, and does not have any edgewise bent portions, so that damage to the flat wire coil can be suppressed or prevented. This is because, compared to bending the segment coil edgewise after inserting the segment coil into the slot of the stator core, the segment coil can be deformed with a smaller force, and even if it comes into contact with another segment coil, the force applied to the other segment coil is also smaller.

In addition, from the viewpoint of realizing a miniaturized rotating electric machine by shortening the coil ends, it is preferable that the position of the end of the circumferential extension portion 213 on the end face 10b side of the stator core 10 in the axial direction of the stator core 10 can be formed by bending and is located as close as possible to the end face 10b. For example, this distance corresponds to the thickness of the rectangular wire segment coil 21.

Furthermore, such a rotating electric machine stator has the secondary advantage that it can be manufactured without a jig or with a simple jig, even when a segment coil with a higher aspect ratio (coil width/coil thickness) is used. Furthermore, when such a rotating electric machine stator is manufactured using a segment coil having an insulating coating, the amount of deformation of the insulating coating is small, so that the insulation quality can be improved. Furthermore, such a rotating electric machine stator has the secondary advantage that the distance between the welded parts can be increased, so that the insulation at the welded parts can be improved.

FIGS. 3 to 10 are diagrams illustrating the stator of the rotating electric machine of the present invention. In the following embodiments, the same components as those in the first embodiment described above are given the same reference numerals, and detailed descriptions of the invention are omitted.

Second Embodiment
The upper view in Fig. 3 is a top view showing a schematic of a portion of the welded side of the segment coil. In the upper view in Fig. 3, the radial direction, circumferential direction, and axial direction are respectively the up-down direction, the left-right direction, and the direction perpendicular to the paper surface. The lower view in Fig. 3 is a front view of a portion of the welded side of the segment coil seen from the outer diameter side. In the lower view in Fig. 3, the radial direction, circumferential direction, and axial direction are respectively the direction perpendicular to the paper surface, the left-right direction, and the up-down direction.

As shown in FIG. 3, in this embodiment, the circumferential extension portion 213 of the rectangular wire coil has the same structure as the stator of the rotating electric machine in the first embodiment, except that it has a twisted portion.

Next, the advantages of this embodiment will be described. According to the stator of the rotating electric machine of this embodiment, the circumferential extension portion 213 has a twisted portion that can be formed with less force than edgewise bending, which can suppress or prevent damage to the rectangular wire coil.

Third Embodiment
The upper views in Figures 4 and 5 are top views showing a schematic of a portion of the welded side of the segment coil. In the upper views in Figures 4 and 5, the radial direction, circumferential direction, and axial direction are respectively the up-down direction, the left-right direction, and the direction perpendicular to the paper surface. The lower views in Figures 4 and 5 are front views of a portion of the welded side of the segment coil as seen from the outer diameter side. In the lower views in Figures 4 and 5, the radial direction, circumferential direction, and axial direction are respectively the direction perpendicular to the paper surface, the left-right direction, and the up-down direction.

As shown in Figures 4 and 5, in this embodiment, the circumferential extension portion 213 of the rectangular wire coil has the same structure as the stator of the rotating electric machine of the first embodiment, except that it has a 180° bent portion (see the triangular fold portion in Figure 4) or a 90° bent portion (see the front part of the page in the left triangular fold portion in Figure 5 and the back part of the page in the right triangular fold portion in Figure 5).

Next, the advantages of this embodiment will be described. According to the stator of the rotating electric machine of this embodiment, the circumferential extension portion 213 has 90° bent portions and 180° bent portions that utilize flatwise bending, which can be formed with less force than edgewise bending, and therefore damage to the rectangular wire coil can be suppressed or prevented.

Fourth Embodiment
As shown in Fig. 6, in this embodiment, each of the multiple slots 10a has segment coils 21A to 21F arranged in a stack in the radial direction of the stator core 10, and the bending directions of the radial bending portions 213 are aligned on the outer diameter side, except that the structure is the same as that of the stator of the rotating electric machine of the first embodiment. In Fig. 6, the radial direction, circumferential direction, and axial direction of the stator core are the left-right direction, the direction perpendicular to the paper surface, and the up-down direction, respectively. The same is true in Figs. 7 and 8.

Next, the advantages of this embodiment will be described. With the stator for a rotating electric machine of this embodiment, the ends 21a of the segment coils 21A to 21F are arranged on the outer diameter side in the radial direction, so in addition to the advantages of the first embodiment, when this stator is applied to a rotating electric machine of the so-called inner rotor type in which a rotor (not shown) is housed on the inner diameter side of the stator, interference between the rectangular wire coil and the rotor can be avoided.

Fifth Embodiment
As shown in Figure 7, in this embodiment, the stator has segment coils 21A to 21F stacked in the radial direction of the stator core 10 in each of the multiple slots 10a, and has the same structure as the stator of the rotating electric machine of the first embodiment, except that the bending direction of the radial bending portions 213 of the segment coils 21A to 21C arranged on the outer diameter side among the multiple segment coils 21A to 21F faces the outer diameter side, and the bending direction of the radial bending portions 213 of the segment coils 21D to 21F arranged on the inner diameter side faces the inner diameter side.

Next, the advantages of this embodiment will be explained. With the stator of the rotating electric machine of this embodiment, the ends 21a of the segment coils 21A to 21C are arranged on the outer diameter side in the radial direction, and the ends 21a of the segment coils 21D to 21F are arranged on the inner diameter side in the radial direction, so in addition to the advantages of the fourth embodiment, the coil ends can be further shortened.

Sixth Embodiment
As shown in Figure 8, this embodiment has the same structure as the stator of the rotating electric machine of the fifth embodiment, except that the axial bending portion 215 is located closer to the end face of the stator core 10 in the axial direction of the stator core 10 than the radial bending portion 211.

Next, the advantages of this embodiment will be described. According to the stator of the rotating electric machine of this embodiment, the axial bend portion 215 is provided closer to the end face of the stator core 10 in the axial direction of the stator core 10 than the radial bend portion 211, so the coil end can be made even shorter than in the fifth embodiment.

Seventh Embodiment
As shown in FIG. 9, in this embodiment, the flat wire coil 20 has the same structure as the stator of the rotating electric machine of the first embodiment, except that it is composed of split coils 201 to 205 split in its width direction (left and right direction in FIG. 9).

Here, the split coils 201 to 205 have a conductor 206, such as copper wire, covered with an insulating coating 207. These split coils 201 to 205 are further covered with an insulating film 208 to form the integrated flat wire coil 20. The conductor 206 extends in the direction perpendicular to the page. The materials of the insulating

coatings

207 and 208 may be the same or different.

Next, the advantages of this embodiment will be described. The stator of the rotating electric machine of this embodiment uses the flat wire coil 20 called Litz wire as described above, so in addition to the advantages of the first embodiment, it is less susceptible to the skin effect and can reduce eddy current loss when used in the high frequency range.

Here, we will explain part of the manufacturing method for the rotating electric machine stator of the second embodiment described above. Figure 10 is an explanatory diagram showing how the rectangular wire coil is formed in the rotating electric machine stator shown in Figure 3. Note that the upper, center, and lower figures on the left side of Figure 10 show multiple slots 10a formed in the circumferential direction linearly expanded. Also, the upper, center, and lower figures on the right side of Figure 10 show the cross-sectional state along line A-A in the corresponding left side figure.

In the upper part of FIG. 10, a segment coil 21 is inserted into each slot 10a. Next, outside the slot 10a, the segment coil 21 is flatwise bent to form a portion that will become a radial bent portion 211 and an axial bent portion 215 by subsequent circumferential bending of the coil. Thereafter, the end portion 21a of the segment coil is bent in the circumferential direction (to the right in FIG. 4) to form a circumferential extension portion 213 having a twisted portion. Note that in order to form the twisted portion, some space is required, as shown by the dotted line in the lower diagram on the right side of FIG. 10. By repeating this operation, the end portions 21a are aligned and welded together at necessary locations to form welded portions 21b, and a stator for a rotating electric machine can be obtained.

The present invention has been described above using a few embodiments, but the present invention is not limited to these, and various modifications are possible within the scope of the gist of the present invention.

The gist of the present invention is that the segment coil is not bent edgewise after it is inserted into the slot of the stator core in order to suppress or prevent damage to the rectangular wire coil.

Thus, although the present invention has been described with an example of application to the stator of an inner rotor type rotating electric machine, this is not intended to be limiting. For example, the present invention can also be applied to the stator of an outer rotor type rotating electric machine. In addition, although a segment coil having a U-shape has been described with an example, this is not intended to be limiting. For example, a segment coil having a straight shape can also be used. Furthermore, although a rectangular wire coil having an insulating coating has been described with an example, this is not intended to be limiting. For example, after a rectangular wire coil without an insulating coating is wound around a stator core, each rectangular wire coil can be coated with a resin material so as to be insulated.

Furthermore, the circumferential extension portion 213 has been described as having a twisted portion that can be formed with less force than edgewise bending, and as having a 90° bent portion or a 180° bent portion that utilizes flatwise bending, but is not limited to these. For example, the circumferential extension portion may have a combination of these portions.

Furthermore, for example, the components described above are not limited to the configurations shown in each embodiment, and it is possible to change the details of the specifications and materials of the stator core, rectangular wire coil, and segment coil, or to replace or combine components of one embodiment with components of another embodiment.

1 Stator of rotating electric machine 10 Stator core 10a Slots 10b, 10c End faces 20, 20A, 20B, 20C Flat wire coils 201 to 205 Split coils 206

Conductors

207, 208 Insulating coatings 21, 21α, 21β, 21A to 21F Segment coils 21a Ends 21b Welded portions 211 Radial bends 213 Circumferential extensions 215 Axial bends

Claims

The stator core is a circular stator core having a plurality of slots in the circumferential direction, and a plurality of segment coils, the segment coils penetrating the slots, protruding from an end face of the stator core in the axial direction, and including a rectangular wire coil wound around the stator core.
An end of one segment coil of the flat wire coil and an end of another segment coil are welded outside the slot to form a welded portion,
A stator for a rotating electric machine, in which the one segment coil and the other segment coil are arranged in the slot and at the welded portion with the thickness direction of the segment coil aligned along a radial direction,
A stator for a rotating electric machine, characterized in that the one segment coil and the other segment coil have a radial bent portion bent radially as they move from the end face side of the stator core to the welded portion side, a circumferential extending portion extending circumferentially adjacent to the radial bent portion, and an axial bent portion bent axially adjacent to the circumferential extending portion, and do not have any edgewise bent portions.
The stator of a rotating electric machine according to claim 1, characterized in that the circumferentially extending portion has a twisted portion.
The stator of a rotating electric machine according to claim 1, characterized in that the circumferential extension portion has a 90° bend portion or a 180° bend portion.
The segment coils are stacked in a radial direction in each of the slots,
2. The stator of claim 1, wherein the bending direction of the radially bent portion is aligned either on the inner diameter side or on the outer diameter side.
The segment coils are stacked in a radial direction in each of the slots,
A stator for a rotating electric machine as described in claim 1, characterized in that the bending direction of the radial bending portion of the segment coil arranged on the outer diameter side among the segment coils faces the outer diameter side, and the bending direction of the radial bending portion of the segment coil arranged on the inner diameter side faces the inner diameter side.
The stator of a rotating electric machine according to claim 1, characterized in that the axially bent portion is located closer to the end face of the stator core in the axial direction than the radially bent portion.
The stator of a rotating electric machine according to claim 1, characterized in that the rectangular wire coil is made of a split coil divided in its width direction.