Stator for rotating electric machines

Abstract

Reduces the axial size of the coil end. [Solution] A stator for a rotating electric machine is disclosed, comprising a stator coil formed by segment coils having a rectangular cross-section, and a stator core having a plurality of slots around which the stator coil is wound, wherein the stator coil has slot insertion portions that are inserted into corresponding slots among the plurality of slots, and connecting portions that are exposed from the axial end face of the stator core and extend circumferentially in a manner that connects pairs of slot insertion portions, and the slot insertion portions have a bent R portion at the end that connects to the connecting portion, which starts from within the slot.

Description

Technical Field

[0001] The present disclosure relates to a stator for a rotating electric machine.

Background Art

[0002] In a configuration in which a stator coil of a stator for a rotating electric machine is formed by segment coils having a rectangular cross section, a technique is known in which open end portions (crossing portions) forming coil ends are formed in a stepped shape. In this case, the crossing portions continuous from each of the two slot insertion portions inserted at the same radial position of two adjacent slots in the circumferential direction are arranged so as to overlap when viewed in the axial direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, the slot insertion portions are linear, and it is difficult to reduce the physical size of the coil end in the axial direction.

[0005] Therefore, on one aspect, the present disclosure aims to reduce the physical size of the coil end in the axial direction.

Means for Solving the Problems

[0006] On one aspect, a stator coil formed by segment coils having a rectangular cross section, and a stator core having a plurality of slots around which the stator coil is wound are provided, wherein the stator coil includes slot insertion portions inserted into corresponding slots among the plurality of slots, The stator core has a connecting portion that is exposed from the axial end face and extends circumferentially in a manner that connects the pair of slot insertion portions, A stator for a rotating electric machine is provided, wherein the slot insertion portion has a bent radius portion that starts from within the slot at the end of the slot that connects to the connecting portion. [Effects of the Invention]

[0007] In one respect, the present disclosure makes it possible to reduce the axial size of the coil end. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view of the stator in this embodiment, viewed in the axial direction. [Figure 2] This is an explanatory diagram showing the configuration of the stator coil in this embodiment. [Figure 3] This is an enlarged view of a portion of Figure 2, illustrating the relationship between two connecting sections that extend from the slot insertion sections within two adjacent slots in the circumferential direction. [Figure 3A] This is an explanatory diagram illustrating the characteristic configuration of this embodiment. [Figure 4] This is an enlarged view showing the characteristic shapes of the slot insertion portion and the connecting portion at the axial end of the slot. [Figure 5] This is a cross-sectional view along line GG in Figure 3A. [Figure 6] This is a cross-sectional view along line HH in Figure 3A. [Figure 7] This is a cross-sectional view along line II in Figure 3A. [Figure 8] This is a cross-sectional view along line JJ in Figure 3A. [Figure 9] This is an explanatory diagram of a comparative example, contrasting with Figure 3A, and illustrating the slot insertion portion, the bent radius portion, and the connecting portion from two specific slots. [Figure 10] This is a cross-sectional view along line I'-I' in Figure 9. [Figure 11] This is a cross-sectional view along the line J'-J' in Figure 9. [Figure 12] It is an explanatory diagram of an example of a manufacturing method for realizing a cross-sectional area profile according to this embodiment.

Mode for Carrying Out the Invention

[0009] Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limited thereto, and the shapes and the like in the drawings may be exaggerated partially for the convenience of explanation. Also, in the drawings, for the sake of clarity, only some of the parts having the same attribute and existing in plurality may be provided with reference numerals.

[0010] Referring to FIGS. 1 and 2, the configuration of the stator 100 according to this embodiment will be described.

[0011] FIG. 1 is a plan view of the stator 100 of this embodiment viewed in the axial direction. FIG. 2 is an explanatory diagram showing the form of the stator coil 20 of this embodiment. FIG. 2 is a schematic diagram showing a part of the stator coil 20 (and the stator core 10) in the circumferential direction developed in a planar shape.

[0012] In the following description, the axial direction, the radial direction, and the circumferential direction of the stator core 10 (see FIG. 1) included in the stator 100 are defined as the Z direction, the R direction, and the C direction, respectively. Also, one side and the other side in the axial direction (Z direction) are defined as the Z1 side and the Z2 side, respectively. Further, the inner side and the outer side in the radial direction (R direction) are defined as the R1 side and the R2 side, respectively. Also, one side and the other side in the circumferential direction (C direction) are defined as the C1 side and the C2 side, respectively.

[0013] As shown in FIG. 1, the stator 100 constitutes a part of an inner rotor type rotating electric machine 102 together with a rotor 101 disposed on the R1 side of the stator 100 so as to face the stator 100. The rotating electric machine 102 is, for example, a motor, a generator, or a motor-generator.

[0014] The stator 100 includes a stator core 10 and a stator coil 20.

[0015] The stator core 10 has a cylindrical shape with a central axis 90 along the Z direction as its central axis. The stator core 10 may be formed by laminating a plurality of electromagnetic steel sheets (for example, silicon steel sheets) in the Z direction. Note that the stator core 10 may also be formed by compression molding of magnetic powder.

[0016] The stator core 10 includes an annular back yoke 11 and a plurality of teeth 12 that project from the back yoke 11 toward the R1 side and are arranged in the C direction. Slots 13 are formed between adjacent teeth 12 in the C direction. That is, the stator core 10 includes a plurality of slots 13 arranged in the C direction. Each of the plurality of teeth 12 and the plurality of slots 13 is formed to extend in the Z direction from the end face 10a on the Z1 side (see FIG. 2) to the end face 10a on the Z2 side of the stator core 10.

[0017] The coil wire forming the stator coil 20 may be composed of a conductor mainly made of any one of copper, copper alloy, aluminum, and aluminum alloy, and an insulating coating covering the conductor. Note that the cross-sectional shape of the conductor may be rectangular. The stator coil 20 may be configured to generate a magnetic flux when, for example, three-phase alternating current is supplied. In FIG. 1, illustration of portions other than the slot insertion portion 31 (see FIG. 2) of the stator coil 20 is omitted.

[0018] The coil wire forming the stator coil 20 is wound around the stator core 10. The winding method of the coil wire is arbitrary and may be wave winding, overlapping winding, or the like.

[0019] As shown in Figure 2, the stator coil 20 is formed by joining together a plurality of segment coils 30. Each of the plurality of segment coils 30 integrally includes a pair of slot insertion portions 31 that are inserted (housed) in the slot 13, a pair of connecting portions 322 that protrude from the Z2 side end face 10a of the stator core 10 toward the Z1 side, and a connecting portion 33 that protrudes toward the Z2 side from the Z2 side end face 10a of the stator core 10.

[0020] While there are typically multiple types of segment coils 30 forming a single stator coil 20, each type may only differ in its shape and length. For example, one type of segment coil 30 may differ from other types of segment coils 30 only in its size, corresponding to the radial position (which turn) in which the slot insertion portion 31 is inserted. In the following, unless otherwise specified, multiple types will not be distinguished.

[0021] Each of the pair of slot insertion portions 31 is housed (inserted) into a different slot 13. Each of the tip portions 32a of the pair of connecting portions 322 is joined (connected) by welding to the tip portion 32a of the connecting portion 322 of the other segment coil 30 on the Z1 side of the stator core 10. The pair of connecting portions 322 thus joined form a single connecting portion 32. Each connecting portion 32 as a whole forms the coil end on the Z1 side. The connecting portion 33 connects the pair of slot insertion portions 31 on the Z2 side of the stator core 10. Each connecting portion 33 as a whole forms the coil end on the Z2 side.

[0022] As shown in Figure 1, each of the multiple slots 13 may house multiple segment coils 30 (specifically, the slot insertion portion 31 (see Figure 2)) arranged in the R direction. In Figure 1, an example is shown where each of the multiple slots 13 houses eight segment coils 30 arranged in the R direction. Note that the number of turns is not limited to eight, but can be any number of two or more.

[0023] As shown in Figure 2, for n≧1 and k≧0, the tip 32a of the connecting portion 322 of the segment coil 30 of the (n+2k) turn and the tip 32a of the connecting portion 322 of the segment coil 30 of the (n+2k+1) turn may be joined (connected) by welding. Note that "the ...th turn segment coil 30" means the ...th column segment coil 30 from the R1 side.

[0024] The connecting portion 322 of the segment coil 30 for the (n+2k) turn includes a tip portion 32a extending along the Z direction, an oblique portion 32b that is inclined with respect to the Z-direction end face 10a of the stator core 10 so as it moves from the Z1 side to the Z2 side, it moves from the C1 side to the C2 side, a stator core side curved portion 32c that curves to connect the Z1 side end of the slot insertion portion 31 and the Z2 side end of the oblique portion 32b, and a tip side curved portion 32d that curves to connect the Z1 side end of the oblique portion 32b and the Z2 side end of the tip portion 32a.

[0025] Although the slanted portion 32b extends in a straight line, it may have non-straight portions (for example, slightly curved portions) due to the effects of molding such as the stator core side curved portion 32c.

[0026] The connecting portion 322 of the segment coil 30 for the (n+2k+1)th turn includes a tip portion 32a extending along the Z direction, an oblique portion 32b inclined with respect to the Z-direction end face 10a of the stator core 10 so as it moves from the Z1 side to the Z2 side, it moves from the C2 side to the C1 side, a stator core side curved portion 32c that curves to connect the Z1 side end of the slot insertion portion 31 and the Z2 side end of the oblique portion 32b, and a tip side curved portion 32d that curves to connect the Z1 side end of the oblique portion 32b and the Z2 side end of the tip portion 32a.

[0027] Figure 3 is an enlarged view of a part of Figure 2, and is an explanatory diagram showing the relationship between two connecting portions 322 that are continuous from the slot insertion portion 31 in two adjacent slots 13 in the circumferential direction. In the following explanation, one of the two connecting portions 322 will be referred to as connecting portion 322A and the other as connecting portion 322B.

[0028] The following describes pairs of connecting parts 322A and 322B from slot insertion parts 31 in two specific slots 13, but the same applies to pairs of connecting parts 322 from slot insertion parts 31 in any other adjacent slots 13 in the circumferential direction. Furthermore, the following describes pairs of connecting parts 322A and 322B that are continuous from the slot insertion part 31 of the first turn, but the same applies to pairs of connecting parts 322 that are continuous from the slot insertion part 31 of the second turn, or pairs of connecting parts 322 that are continuous from the slot insertion part 31 of the third turn, etc. Also, the following describes pairs of connecting parts 322A and 322B that tilt towards C2, referring to Figure 3, but the same applies to pairs of connecting parts 322 that tilt towards C1.

[0029] In this embodiment, the pair of connecting portions 322A and 322B are bent in the same direction in the circumferential direction and overlap when viewed in the axial direction. In the example shown in Figure 3, the pair of connecting portions 322A and 322B are bent toward C2 and overlap when viewed in the axial direction. Note that the pair of connecting portions 322A and 322B shown in Figure 2 overlap when viewed in the axial direction in a circumferential range from the C1 side end of connecting portion 322B to the C2 side end of connecting portion 322A, as shown in Figure 3. Hereafter, the circumferential range in which such a pair of connecting portions 322A and 322B overlap when viewed in the axial direction will also be simply referred to as the "circumferential range that overlaps in the axial direction".

[0030] The pair of connecting portions 322A and 322B are in contact with or close to each other in the axial direction within a circumferential range where they overlap in the axial direction. In the example shown in Figure 3, the respective oblique portions 32b of the pair of connecting portions 322A and 322B are in contact with or close to each other in the axial direction. In this case, the portions of the oblique portions 32b of the pair of connecting portions 322A and 322B that overlap in the axial direction are in contact with or close to each other in the axial direction. Hereinafter, the portions of the oblique portions 32b of the pair of connecting portions 322A and 322B that overlap in the axial direction will also be referred to as the "overlapping oblique portions 320b in the axial direction".

[0031] In this embodiment, the pair of connecting portions 322A and 322B do not have a constant cross-sectional area at each point along their respective longitudinal directions, but rather have the cross-sectional area profile described below. In the following description, the cross-sectional area refers to the cross-sectional area of ​​the section cut by a plane normal to the longitudinal direction of the coil wire, and is the cross-sectional area of ​​the conductor portion (excluding the insulating coating).

[0032] Here, the cross-sectional areas from point A to point F in Figure 3 are denoted as SA to SF. Cross-sectional area SA is the cross-sectional area at the stator core side curved portion 32c, and corresponds to the cross-sectional area related to the section passing through the center of curvature of the bend shape of the stator core side curved portion 32c. Cross-sectional area SB corresponds to the cross-sectional area of ​​the division portion closer to the stator core side curved portion 32c (hereinafter also referred to as "end portion 321c") when the slanted portion 32b is divided into three parts in the longitudinal direction. Cross-sectional area SC corresponds to the cross-sectional area of ​​the central division portion (hereinafter also referred to as "central portion 321b") when the slanted portion 32b is divided into three parts in the longitudinal direction. Cross-sectional area SD corresponds to the cross-sectional area of ​​the division portion closer to the tip side curved portion 32d (hereinafter also referred to as "end portion 321d") when the slanted portion 32b is divided into three parts in the longitudinal direction. The cross-sectional area SE is the cross-sectional area at the tip-side curved portion 32d, and corresponds to the cross-sectional area related to the section passing through the center of curvature of the bend shape of the tip-side curved portion 32d. The cross-sectional area SF is the cross-sectional area at the tip portion 32a.

[0033] In this case, if the cross-sectional area at the slot insertion portion 31 is S0, then the following relationship holds in this embodiment.

[0034] S0 > max (SA to SE) Here, max(SA to SE) is the maximum value between SA and SE. In other words, the cross-sectional area of ​​the connecting portion 32 is basically smaller than the cross-sectional area of ​​the slot insertion portion 31. This makes it possible to reduce the axial size of the coil end. For example, the cross-sectional areas SB, SC, and SD of the oblique portion 32b are 2.5% or more smaller than the cross-sectional area S0 of the slot insertion portion 31, and preferably 12% or more smaller. For example, the cross-sectional area SC of the central portion 321b is preferably 12% or more smaller than the cross-sectional area S0. The cross-sectional area SF may be approximately the same as the cross-sectional area S0.

[0035] Furthermore, in this embodiment, the following relationships exist. SA > SC, and SE > SC In other words, the cross-sectional area SC at the central part 321b of the slanted portion 32b is smaller than the cross-sectional areas SA and SE of the stator core side curved portion 32c and the tip side curved portion 32d, respectively.

[0036] Furthermore, in this embodiment, the following relationships exist. SB > SC, and SD > SC In other words, the cross-sectional area SC at the central part 321b of the slanted portion 32b is smaller than the respective cross-sectional areas SB and SD at both ends 321c and 321d of the slanted portion 32b. For example, the cross-sectional area SC is 5% or more smaller than the respective cross-sectional areas SB and SD, preferably 7% or more smaller. This makes it possible to reduce the axial size of the coil end.

[0037] With such a cross-sectional area profile, the cross-sectional area can be reduced at the central part 321b of the slanted portion 32b. The central part 321b of the slanted portion 32b forms the slanted portion 320b that overlaps in the axial direction as described above. Therefore, according to this embodiment, the axial size of the coil end can be reduced. Furthermore, if the cross-sectional area SC is smaller than the respective cross-sectional areas SB and SD, the dimension that contributes to the axial size of the coil end (axial dimension) will also be smaller at the central part 321b of the slanted portion 32b than at both ends 321c and 321d.

[0038] Next, the characteristic configuration of this embodiment will be further explained, mainly with reference to Figure 3A and subsequent figures.

[0039] Figure 3A is an explanatory diagram of the characteristic configuration of this embodiment. Figure 3A is the same as Figure 3 above (the picture itself is the same), but the reference numerals and other elements have been changed to explain the characteristic configuration of this embodiment. Figure 4 is an enlarged view showing the characteristic shapes of the slot insertion portion 31 and the connecting portion 322 at the axial end of the slot 13. Figures 5 and 6 are cross-sectional views of a single segment coil 30, with Figure 5 being a cross-sectional view along line GG in Figure 3A, and Figure 6 being a cross-sectional view along line HH in Figure 3A.

[0040] In this embodiment, as shown in Figure 4, the slot insertion portion 31 has a bent radius portion 312 at the end that connects to the connecting portion 322. The bent radius portion 312 of one slot insertion portion 31 starts from within the corresponding slot 13. This reduces the axial size of the coil end. The bent radius portion 312 is formed by edgewise bending. The bent radius portion 312 forms the end of the slot insertion portion 31 while also forming the end of the connecting portion 322 on the slot insertion portion 31 side. That is, the bent radius portion 312 forms the respective ends between the slot insertion portion 31 and the connecting portion 322.

[0041] In this embodiment, the circumferential width Ls of the slot 13 is greater than the width Lc of the segment coil 30 (width on the edgewise bending side), as shown in Figure 4. This facilitates the formation of the bend radius 312 (edgewise bending) starting from within the corresponding slot 13. Furthermore, the bend radius can be made relatively small. This reduces the axial size of the coil end.

[0042] When edgewise bending is performed, as shown in Figure 5, the side 510 on the bending center side becomes longer than the opposing side 502. That is, the bent radius portion 312 has a trapezoidal cross-sectional shape in which the side 510 on the bending center side is longer than the opposing side 502. On the other hand, near the center of the connecting portion 322, as shown in Figure 6, it has a rectangular cross-sectional shape that corresponds to the cross-sectional shape of the original segment coil 30.

[0043] Here, with reference to Figures 7 to 11, further effects of this embodiment will be explained.

[0044] Figures 7 and 8 are cross-sectional views showing the relationship between four connecting portions 322 from one slot 13. Figure 7 is a cross-sectional view along line II in Figure 3A, and Figure 8 is a cross-sectional view along line JJ in Figure 3A. Figures 9 to 11 are explanatory diagrams of comparative examples. Figure 9 is a diagram for comparison with Figure 3A and is an explanatory diagram showing the slot insertion portion 31', the bent R portion 312', and the connecting portion 322' from two specific slots 13. Figures 10 and 11 are cross-sectional views of one segment coil 30'. Figure 10 is a cross-sectional view along line I'-I' in Figure 9, and Figure 11 is a cross-sectional view along line J'-J' in Figure 9.

[0045] In the comparative examples shown in Figures 9 to 11, the bent radius portion 312' does not start from inside the slot 13, but from the axial outside of the slot 13. In this case, as shown in Figures 10 and 11, the bent radius portion 312' has a rectangular cross-sectional shape inside the slot 13 and at the exit (axial end) from the slot 13. Therefore, in this case, the gap Δ' (radial gap) between each radially adjacent connecting portion 322' inside the slot 13 and at the exit (axial end) from the slot 13 remains relatively small and unchanged. As a result, it is difficult for oil (cooling oil) to pass between the connecting portions 322', making it difficult to efficiently cool each connecting portion 322'.

[0046] In contrast, in this embodiment, as described above, the bent R portion 312 has a trapezoidal cross-sectional shape, so as shown in Figure 7, within the slot 13, each slot insertion portion 31 (bent R portion 312) is arranged radially in such a manner that the long side and short side alternate in the radial direction. As a result, even at the exit from the slot 13 (axial end), no inconvenience such as interference between each slot insertion portion 31 due to the bent R portion 312 occurs. Furthermore, as shown in Figure 8, the bent R portion 312 in the connecting portion 322 is located on the side that moves away in the circumferential direction with each turn, so the gap Δ (radial gap) between each radially adjacent connecting portion 322 becomes larger. As a result, oil (cooling oil) can easily pass between these connecting portions 322, making it possible to efficiently cool each connecting portion 322 (and thus the connecting portion 33).

[0047] Next, we will outline an example of a manufacturing method for achieving the preferred cross-sectional area profile according to the above-described embodiment.

[0048] Figure 12 is an explanatory diagram of an example of a manufacturing method for realizing the cross-sectional area profile according to this embodiment.

[0049] Referring to Figures 3 to 8, the cross-sectional area profile according to this embodiment described above may be realized by any method, for example, by joining together conductive pieces (with insulating coatings) having the corresponding cross-sectional area, but preferably by the method conceptually shown in Figure 12. In the example shown in Figure 12, a substantially U-shaped segment coil 30A, which is the material for forming the segment coil 30, is shown. In this case, the segment coil 30A can be formed by bending it circumferentially starting from P1 near the axial end of the slot insertion portion 31 (see arrow R41), then pulling it outward in the axial direction (see arrow R42), and bending it inward in the circumferential direction starting from P2 near the outer circumferential end of the oblique portion 32b (see arrow R43). In this case, the stator core side curved portion 32c is formed by bending near P1 near the axial end, and the tip side curved portion 32d is formed by bending near P2 near the outer circumferential end.

[0050] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above. [Explanation of Symbols]

[0051] 102 Rotating electric machine, 100 Stator, 10 Stator core, 10a End face (axial end face), 13 Slot, 30 Segment coil, 31 Slot insertion part, 32 Connecting part, 312 Bending radius part, 322 Connecting forming part

Claims

1. A stator coil formed by segment coils having a rectangular cross-section, It comprises a stator core having multiple slots around which the stator coil is wound, The stator coil is, A slot insertion portion inserted into each corresponding slot among the plurality of slots, The stator core has a connecting portion that is exposed from the axial end face and extends circumferentially in a manner that connects the pair of slot insertion portions, The slot insertion portion has a bent radius portion that starts from within the slot at the end that connects to the connecting portion, in the stator for a rotating electric machine.

2. The stator for a rotating electric machine according to claim 1, wherein the crossover portion has a smaller cross-sectional area than the slot insertion portion.

3. Each of the connecting portions on one side in the axial direction is formed by joining two connecting portions from a pair of slot insertion portions. The stator for a rotating electric machine according to claim 1, wherein a plurality of connecting forming portions extending from a single slot are bent radially adjacent to each other on different sides in the circumferential direction.

4. The stator for a rotating electric machine according to any one of claims 1 to 3, wherein the bent R portion has a trapezoidal cross-sectional shape in which the first side on the bending center side is longer than the second side opposite the first side.

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