Stator of a rotating electric machine

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

Technical Field

[0001] The present invention relates to a stator of a rotating electrical machine, and more particularly to a stator of a rotating electrical machine capable of suppressing or preventing damage to a rectangular wire coil.

Background Art

[0002] Conventionally, there has been proposed a rectangular wire forming device capable of performing edgewise bending processing on a rectangular wire and further improving the forming accuracy of the rectangular wire (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when edgewise bending processing is performed on a segment coil using a rectangular wire forming device as described in Patent Document 1 and a rectangular wire coil is wound around the stator of a rotating electrical machine, the distance between the processed parts of the segment coils is short, so it is impossible to secure a space for arranging the pressing jig of the rectangular wire forming device. Therefore, there is a problem that the segment coil may fall over and the rectangular wire coil may be damaged due to contact with another segment coil.

[0005] The present invention has been made in view of such problems of the prior art, and an object thereof is to provide a stator of a rotating electrical machine capable of suppressing or preventing damage to a rectangular wire coil.

Means for Solving the Problems

[0006] The inventors of the present invention have conducted extensive research to achieve the above objective and have found that the above objective can be achieved if one segment coil and the other segment coils of the flat rectangular wire coil have a radially bent portion that is bent radially, a circumferentially extended portion that extends circumferentially adjacent to the radially bent portion, and an axially bent portion that is bent axially adjacent to the circumferentially extended portion, and do not have an edgewise bent portion, as they transition from the end face side of the stator core to the welded portion side, and have completed the present invention.

[0007] In other words, the stator of the rotating electric machine of the present invention comprises an annular stator core having a plurality of slots in the circumferential direction, and a plurality of flat rectangular wire segment coils, the segment coils passing through the slots and protruding axially from the end face of the stator core and wound around the stator core. In this flat rectangular wire coil, the end of one segment coil and the end of another segment coil are welded outside the slot to form a welded joint. One segment coil and the other segment coils are arranged within the slot and at the weld so that the thickness direction of the segment coils is aligned with the radial direction. Each segment coil and the other segment coil have a radially bent portion, a circumferentially extended portion adjacent to the radially bent portion and extending circumferentially, and an axially bent portion adjacent to the circumferentially extended portion, as they transition from the end face side of the stator core to the weld side, and do not have any edgewise bent portions. [Effects of the Invention]

[0008] According to the present invention, one segment coil and the other segment coils of the rectangular wire coil have a radially bent portion that is bent radially, a circumferentially extended portion that extends circumferentially adjacent to the radially bent portion, and an axially bent portion that is bent axially adjacent to the circumferentially extended portion, and there are no edgewise bent portions, thereby providing a stator for a rotating electric machine that can suppress or prevent damage to the rectangular wire coil. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing a first embodiment of the stator of the rotating electric machine of the present invention. [Figure 2] Figure 1 is a schematic diagram illustrating a part of the stator of the rotating electric machine shown. [Figure 3] This is a schematic diagram illustrating a portion of the flat wire coil in the stator of a rotating electric machine according to the second embodiment. [Figure 4] This is a schematic diagram illustrating a part of an example of a flat wire coil in the stator of a rotating electric machine according to the third embodiment. [Figure 5] This is a schematic diagram illustrating some other examples of flat wire coils in the stator of a rotating electric machine according to the third embodiment. [Figure 6] This is a schematic diagram illustrating a portion of the flat wire coil in the stator of a rotating electric machine according to the fourth embodiment. [Figure 7] This is a schematic diagram illustrating a portion of the flat wire coil in the stator of a rotating electric machine according to the fifth embodiment. [Figure 8] This is a schematic diagram illustrating a portion of the flat wire coil in the stator of a rotating electric machine according to the sixth embodiment. [Figure 9] This is a schematic cross-sectional view showing a portion of the flat wire coil in the stator of the seventh embodiment of a rotating electric machine. [Figure 10] Figure 3 is an explanatory diagram showing the process of forming the flat wire coils in the stator of the rotating electric machine. [Modes for carrying out the invention]

[0010] 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 in the drawings cited below are exaggerated for illustrative purposes and may differ from the actual ratios. In addition, in the present invention, "circumferential direction," "axial direction," and "radial direction" refer to the circumferential direction, axial direction, and radial direction of the annular stator core, respectively. Furthermore, in the present invention, "inner diameter side" and "outer diameter side" refer to the inner diameter side (inner circumferential surface side) and outer diameter side (outer circumferential surface side) of the annular stator core, respectively.

[0011] (First Embodiment) Figure 1 is a perspective view of the stator of the rotating electric machine of this embodiment, viewed from the segment coil insertion side. Figure 2 is a front view, viewed from the outer diameter side, of a portion of the welded side of the segment coils stacked at the 5th and 6th positions from the inner diameter side in the stator of the rotating electric machine shown in Figure 1. Note that in Figure 2, for explanatory purposes, the segment coils stacked at the 1st to 4th positions from the inner diameter side are omitted.

[0012] As shown in Figure 1, the stator 1 of the rotating electric machine in this embodiment comprises a stator core 10 and a flat rectangular wire coil 20 wound around the stator core 10.

[0013] Here, the stator core 10 is annular in shape and has a plurality of slots 10a in the circumferential direction of the stator core 10. As such a stator core 10, for example, an integrated stator core formed by stacking a plurality of annular electromagnetic steel sheets in the axial direction of the stator core 10 can be used. In the illustrated example, there are 48 slots.

[0014] In addition, the flat rectangular coil 20 is composed of a plurality of segment coils 21, and the segment coils 21 penetrate through the slots 10a and have a plurality of flat rectangular coils 20A, 20B, and 20C protruding in the axial direction of the stator core 10 from the end face 10b on the welding side and the end face 10c on the insertion side of the stator core 10. As such a flat rectangular coil 20, for example, it is preferable to use a U-shaped flat rectangular coil having an insulating film (not shown) other than the end portion 21a that forms the welding portion 21b, which will be described in detail later. Further, from the viewpoint of reducing current loss, the aspect ratio (coil width / coil thickness) of the flat rectangular coil 20 is preferably as large as possible. On the other hand, as the aspect ratio increases and the coil becomes longer, it becomes more likely to bend due to its own weight, or in other words, it becomes less self-supporting. There is such a trade-off relationship in the aspect ratio of the flat rectangular coil. When further examining this trade-off relationship, from the viewpoints of ease of flatwise bending and ensuring the quality of the coil, the aspect ratio (coil width / coil thickness) of the flat rectangular coil 20 is preferably 2 or more, more preferably 3 or more, still more preferably 5 or more, preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less. Note that the illustrated example is a three-phase type, and these phases are referred to as the U phase, V phase, and W phase.

[0015] As shown in FIG. 2, the end portion 21a of one segment coil 21α of the flat rectangular coil 20 and the end portion 21a of another segment coil 21β are welded outside the slot 10a (see FIG. 1) to form a welding portion 21b. In the present embodiment, as shown in FIGS. 1 and 2, the end portion 21a of the segment coil 21 of the flat rectangular coil 20 and the end portion 21a of another segment coil 21 are welded outside the slot 10a to form a welding portion 21b.

[0016] Furthermore, one segment coil 21α and the other segment coil 21β are arranged in the slot 10a and at the welded portion 21b such that the thickness directions of the segment coils 21α and 21β are along the radial direction of the stator core 10. Note that the thickness directions of the segment coils 21α and 21β and the radial direction of the stator core 10 are in the direction perpendicular to the paper surface (front side and back side) at the center of FIG. 2, and are approximately in the direction perpendicular to the paper surface (front side and back side) on the right and left sides of FIG. 2.

[0017] Furthermore, while the one segment coil 21α and the other segment coil 21β are moving from the end face 10b side of the stator core 10 to the welded portion 21b side, they have a radial bending portion 211, a circumferential extension portion 213, and an axial bending portion 215, and do not have a portion bent edgewise.

[0018] Here, the radial bending portion 211 is bent radially by flatwise bending. The circumferential extension portion 213 extends in the circumferential direction adjacent to the radial bending portion 211. The axial bending portion 215 is bent axially by flatwise bending adjacent to the circumferential extension portion 213.

[0019] Note that the radial side, circumferential side, and axial side of one segment coil 21α laminated and arranged at the sixth (even-numbered) position from the inner diameter side in the radial direction are the outer diameter direction side (front side of the paper surface in FIG. 2), the counterclockwise direction (right side in FIG. 2) when looking at the welded portion 21b from the axial direction, and the axial direction (upper side in FIG. 2), respectively. Also, the radial side, circumferential side, and axial side of the other segment coil 21β laminated and arranged at the fifth (odd-numbered) position from the inner diameter side in the radial direction are the outer diameter direction side (front side of the paper surface in FIG. 2), the clockwise direction (left side in FIG. 2) when looking at the welded portion 21b from the axial direction, and the axial direction (upper side in FIG. 2), respectively.

[0020] Next, the advantages of this embodiment will be described. According to the stator 1 of the rotating electric machine of this embodiment, the flat wire coil has the radially bent portion 211, the circumferentially extended portion 213, and the axially bent portion 215 described above, and does not have an edgewise bent portion, so damage to the flat wire coil can be suppressed or prevented. The reason for this is that, compared to the case in which the segment coil is edgewise bent after inserting the segment coil into the slot of the stator core, the segment coil can be deformed with a small force, and even if it comes into contact with another segment coil, the force applied to the other segment coil will also be small.

[0021] Furthermore, from the viewpoint of achieving miniaturization of the rotating electric machine by shortening the coil end, it is preferable that the position of the end of the circumferentially extended portion 213 on the end face 10b side of the stator core 10 in the axial direction of the stator core 10 is such that it can be formed by bending and is at the closest distance from the end face 10b. For example, that distance corresponds to the thickness of the flat rectangular wire type segment coil 21.

[0022] Furthermore, such a stator for a rotating electric machine has the secondary advantage of being able to be manufactured without or with simple jigs, even when using segment coils with a higher aspect ratio (coil width / coil thickness). In addition, when such a stator for a rotating electric machine is manufactured using segment coils with an insulating coating, the amount of deformation of the insulating coating is reduced, thus improving the insulation quality. Furthermore, such a stator for a rotating electric machine has the secondary advantage of being able to widen the spacing between welds, thus improving the insulation performance at the welds.

[0023] Figures 3 to 10 illustrate the stator of the rotating electric machine of the present invention. In the following embodiments, the same reference numerals are used for the same components as in the first embodiment described above, and detailed inventions are omitted.

[0024] (Second Embodiment) The upper view in Figure 3 is a schematic top view showing a portion of the welded side of the segment coil. In the upper view in Figure 3, the radial direction, circumferential direction, and axial direction are the vertical direction, left-right direction, and vertical direction, respectively. The lower view in Figure 3 is a front view of a portion of the welded side of the segment coil, viewed from the outer diameter side. In the lower view in Figure 3, the radial direction, circumferential direction, and axial direction are the vertical direction, left-right direction, and vertical direction, respectively.

[0025] As shown in Figure 3, in this embodiment, the circumferentially extended 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 twisted portion.

[0026] Next, the advantages of this embodiment will be described. According to the stator of the rotating electric machine of this embodiment, the circumferentially extended portion 213 has a twisted portion that can be formed with a smaller force than edgewise bending, thereby suppressing or preventing damage to the flat wire coil.

[0027] (Third embodiment) The upper views in Figures 4 and 5 are schematic top views showing 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 the vertical direction, left-right direction, and vertical direction, respectively. The lower views in Figures 4 and 5 are front views of a portion of the welded side of the segment coil, viewed from the outer diameter side. In the lower views in Figures 4 and 5, the radial direction, circumferential direction, and axial direction are the vertical direction, left-right direction, and vertical direction, respectively.

[0028] As shown in Figures 4 and 5, in this embodiment, the circumferentially extended portion 213 of the flat 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° bend portion (see the triangular overlapping portion in Figure 4) or a 90° bend portion (see the front portion of the left triangular overlapping portion in Figure 5 and the back portion of the right triangular overlapping portion).

[0029] Next, the advantages of this embodiment will be described. According to the stator of the rotating electric machine of this embodiment, the circumferentially extended portion 213 has 90° bent portions and 180° bent portions that utilize flatwise bending, which can be formed with less force than edgewise bending, thereby suppressing or preventing damage to the flat rectangular wire coil.

[0030] (Fourth embodiment) As shown in Figure 6, this embodiment has the same structure as the stator of the rotating electric machine of the first embodiment, except that each of the multiple slots 10a has segment coils 21A to 21F stacked radially within the stator core 10, and the bending direction of the radially bent portion 213 is aligned with the outer diameter side. In Figure 6, the radial, circumferential, and axial directions of the stator core are the left-right direction, the direction perpendicular to the plane of the paper, and the up-down direction, respectively. The same applies to Figures 7 and 8.

[0031] Next, the advantages of this embodiment will be described. According to the stator of the 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. In addition to the advantages of the first embodiment, when this stator is applied to a so-called inner rotor type rotating electric machine in which a rotor (not shown) is housed on the inner diameter side of the stator, interference between the flat wire coils and the rotor can be avoided.

[0032] (Fifth embodiment) As shown in Figure 7, in this embodiment, there are segment coils 21A to 21F stacked radially within each of the multiple slots 10a of the stator core 10, and the bending direction of the radially bent portions 213 of the segment coils 21A to 21C arranged on the outer diameter side is toward the outer diameter side, and the bending direction of the radially bent portions 213 of the segment coils 21D to 21F arranged on the inner diameter side is toward the inner diameter side, except that the structure is the same as the stator of the rotating electric machine of the first embodiment.

[0033] Next, the advantages of this embodiment will be described. According to 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. Therefore, in addition to the advantages of the fourth embodiment, the coil ends can be further shortened.

[0034] (Sixth Embodiment) As shown in Figure 8, this embodiment has the same structure as the stator of the fifth embodiment of a rotating electric machine, except that the axial bend portion 215 is located closer to the end face of the stator core 10 than the radial bend portion 211 in the axial direction of the stator core 10.

[0035] Next, the advantages of this embodiment will be described. In the stator of the rotating electric machine of this embodiment, the axial bend portion 215 is located closer to the end face of the stator core 10 than the radial bend portion 211 in the axial direction of the stator core 10, so the coil end can be shortened even further than in the fifth embodiment.

[0036] (Seventh Embodiment) As shown in Figure 9, in this embodiment, the flat wire coil 20 has the same structure as the stator of the rotating electric machine in the first embodiment, except that it consists of divided coils 201 to 205 which are divided in the width direction (left-right direction in Figure 9).

[0037] Here, the segmented coils 201 to 205 have a conductor 206, such as copper wire, covered with an insulating coating 207. These segmented coils 201 to 205 are then covered with an insulating coating 208 to form an integrated flat wire coil 20. The conductor 206 extends in the direction perpendicular to the plane of the paper. The materials of the insulating coatings 207 and 208 may be the same or different.

[0038] Next, the advantages of this embodiment will be described. According to the stator of the rotating electric machine of this embodiment, since a flat rectangular wire coil 20 called Litz wire as described above is used, in addition to the advantages of the first embodiment, it is less susceptible to the skin effect and can reduce eddy current losses when used in the high-frequency range.

[0039] Here, we will explain a part of the manufacturing method for the stator of the second embodiment of the rotating electric machine described above. Figure 10 is an explanatory diagram showing the process of forming the flat wire coil in the stator of the rotating electric machine shown in Figure 3. In the upper, middle, and lower views on the left side of Figure 10, the multiple slots 10a formed in the circumferential direction are shown unfolded in a linear manner. Also, in the upper, middle, and lower views on the right side of Figure 10, the cross-sectional state along line AA in the corresponding left view is shown.

[0040] In the upper part of Figure 10, segment coils 21 are inserted into each slot 10a. Next, outside the slots 10a, flatwise bending is used to form portions of the segment coil 21 that will become radially bent portions 211 and axially bent portions 215 by subsequent circumferential bending of the coil. After that, by bending the ends 21a of the segment coil in the circumferential direction (to the right in Figure 4), a circumferentially extended portion 213 with a twisted portion is formed. Note that in order to form the twisted portion, a small space is required, as shown by the dotted line in the lower right side of Figure 10. By repeating this operation to align the ends 21a and welding the ends 21a together at the necessary locations to form welded portions 21b, a stator for a rotating electric machine can be obtained.

[0041] Although the present invention has been described above with reference to some embodiments, the present invention is not limited thereto, and various modifications are possible within the scope of the gist of the present invention.

[0042] In this invention, the core principle is to prevent or suppress damage to the flat wire coil by inserting the segment coil into the slot of the stator core and then avoiding edgewise bending of the segment coil.

[0043] Therefore, although the example given is the application to the stator of a rotating electric machine with an inner rotor, the invention is not limited to this. For example, it can also be applied to the stator of a rotating electric machine with an outer rotor. Furthermore, although the example given is a segment coil having a U-shape, the invention is not limited to this. For example, a segment coil having a straight shape can also be used. In addition, although the example given is a flat wire coil having an insulating coating, the invention is not limited to this. For example, after winding a flat wire coil without an insulating coating onto the stator core, a resin material may be applied to insulate each flat wire coil.

[0044] Furthermore, while examples were given of cases where the circumferentially extended portion 213 has a twisted portion that can be formed with less force than edgewise bending, and cases where it has 90° bent portions or 180° bent portions utilizing flatwise bending, the invention is not limited to these. For example, the circumferentially extended portion may have a combination of these portions.

[0045] Furthermore, for example, the components described above are not limited to the configurations shown in each embodiment. It is also possible to change the details of the specifications and materials of the stator core, flat wire coil, and segment coil, or to replace or combine components of one embodiment with components of another embodiment. [Explanation of Symbols]

[0046] 1. Stator of a rotating electric machine 10 Stator Cores 10a slot 10b,10c end face 20, 20A, 20B, 20C Flat Rectangular Wire Coil 201-205 Split Coil 206 Conductor 207,208 Insulating coating 21, 21α, 21β, 21A~21F Segment Coils 21a End 21b Weld 211 Radial bending section 213 Circumferential extension part 215 Axial bend section

Claims

1. The stator comprises an annular stator core having a plurality of slots in the circumferential direction, and a plurality of segment coils, the segment coils passing through the slots and protruding axially from the end face of the stator core, and a flat rectangular wire coil wound around the stator core. The end of one segment coil and the end of another segment coil of the aforementioned rectangular wire coil are welded outside the slot to form a welded joint. The stator of a rotating electric machine is such that the first segment coil and the other segment coil are arranged in the slot and the welded portion with the thickness direction of the segment coil aligned with the radial direction, The first segment coil and the other segment coil have a radially bent portion that is bent radially, a circumferentially extended portion that extends circumferentially adjacent to the radially bent portion, and an axially bent portion that is bent axially adjacent to the circumferentially extended portion, as they transition from the end face side of the stator core to the welded portion side, and do not have any edgewise bent portions. A stator for a rotating electric machine characterized by the following features.

2. The stator of a rotating electric machine according to claim 1, characterized in that the circumferentially extended portion has a twisted portion.

3. The stator of a rotating electric machine according to claim 1, characterized in that the circumferentially extended portion has a 90° bent portion or a 180° bent portion.

4. Each of the aforementioned slots has the segment coils arranged in a radial stack within it, The bending direction of the radially bent portion is aligned to either the inner diameter side or the outer diameter side. A stator for a rotating electric machine according to feature 1.

5. Each of the aforementioned slots has the segment coils arranged in a radial stack within it, Of the segment coils, the segment coils arranged on the outer diameter side have a bending direction towards the outer diameter, and the segment coils arranged on the inner diameter side have a bending direction towards the inner diameter. A stator for a rotating electric machine according to feature 1.

6. The stator of a rotating electric machine according to claim 1, characterized in that the axially bent portion is provided closer to the end face of the stator core in the axial direction than the radially bent portion.

7. The stator of the rotating electric machine according to claim 1, characterized in that the flat rectangular wire coil consists of divided coils that are divided in the width direction thereof.

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