Stator for rotating electrical machine

Abstract

Disclosed is a stator for a rotating electrical machine, said stator comprising a stator coil formed by a segment coil having a rectangular cross section and a stator core which has a plurality of slots and around which the stator coil is wound, wherein the stator coil has slot insertion parts to be inserted respectively into corresponding slots among the plurality of slots and a crossover part which is exposed from an axial end face of the stator core and which extends in a circumferential direction in such a way as to connect a pair of slot insertion parts, and a cross-sectional area of the crossover part is smaller than a cross-sectional area of the slot insertion part.

Description

Stator for rotating electrical machine

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

[0002] In a configuration in which a stator coil of a stator for a rotating electrical machine is formed by a segment conductor having a rectangular cross section, a technique is known in which a bridging portion (open end portion) forming a coil end is formed in a pair of stepped shapes that go up and down. In this case, the bridging portions continuous from each of the two slot insertion portions inserted at the same radial position in two adjacent slots in the circumferential direction are bent in the same direction in the circumferential direction and are arranged so as to overlap when viewed in the axial direction.

[0003] Japanese Patent Application Laid-Open No. 2009-95167

[0004] However, in the conventional technology as described above, the cross-sectional area of the rectangular cross section of the segment conductor is constant, and it is difficult to reduce the physical size of the coil end in the axial direction.

[0005] Therefore, on one side, the present disclosure aims to reduce the physical size of the coil end in the axial direction in a configuration in which a stator coil is formed by a segment conductor having a rectangular cross section.

[0006] On one side, there is provided a stator for a rotating electrical machine, comprising: a stator coil formed by a segment coil 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 inserted into corresponding slots among the plurality of slots; and a bridging portion that extends in the circumferential direction in a manner of connecting between the pair of slot insertion portions and is exposed from an axial end face of the stator core, and the cross-sectional area of the bridging portion is smaller than the cross-sectional area of the slot insertion portion.

[0007] On one side, according to the present disclosure, in a configuration in which a stator coil is formed by a segment conductor having a rectangular cross section, it is possible to reduce the physical size of the coil end in the axial direction.

[0008] This is a plan view of the stator of this embodiment, viewed in the axial direction. This is an explanatory diagram showing the configuration of the stator coil of this embodiment. This is an enlarged view of a part of Figure 2, and is an explanatory diagram showing the relationship between two connecting forming portions that are continuous from the slot insertion portions in two adjacent slots in the circumferential direction. This is an explanatory diagram of an example of a manufacturing method for realizing the cross-sectional area profile according to this embodiment.

[0009] The following describes each embodiment in detail with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not exhaustive. Furthermore, shapes and other details in the drawings may be partially exaggerated for illustrative purposes. Also, for clarity, in some cases, only a portion of parts with the same attribute are assigned reference numerals in the drawings.

[0010] The configuration of the stator 100 according to this embodiment will be described with reference to Figures 1 and 2.

[0011] Figure 1 is a plan view of the stator 100 of this embodiment, viewed in the axial direction. Figure 2 is an explanatory diagram showing the configuration of the stator coil 20 of this embodiment. Figure 2 is a schematic diagram showing a portion of the stator coil 20 (and stator core 10) in the circumferential direction unfolded in a planar manner.

[0012] In the following description, the axial, radial, and circumferential directions of the stator core 10 (see Figure 1) of the stator 100 will be referred to as the Z direction, R direction, and C direction, respectively. Furthermore, one side and the other side in the axial direction (Z direction) will be referred to as the Z1 side and the Z2 side, respectively. Also, the inner and outer sides in the radial direction (R direction) will be referred to as the R1 side and the R2 side, respectively. Furthermore, one side and the other side in the circumferential direction (C direction) will be referred to as the C1 side and the C2 side, respectively.

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

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

[0015] The stator core 10 has a cylindrical shape with a central axis A along the Z direction. The stator core 10 may be formed by laminating a plurality of electromagnetic steel sheets (for example, silicon steel sheets) in the Z direction. Alternatively, the stator core 10 may 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 protrude from the back yoke 11 toward the R1 side and are arranged in the C direction. A slot 13 is formed between each adjacent tooth 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 Z1 side end face 10a (see Figure 2) to the Z2 side end face 10a of the stator core 10.

[0017] The coil wire forming the stator coil 20 may consist of a conductor mainly composed of copper, copper alloy, aluminum, and aluminum alloy, and an insulating coating covering the conductor. The cross-sectional shape of the conductor may be rectangular. The stator coil 20 may be configured to generate magnetic flux when, for example, three-phase alternating current power is supplied. Note that in Figure 1, the parts of the stator coil 20 other than the slot insertion portion 31 (see Figure 2) are not shown.

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

[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] In addition, there are typically multiple types of segment coils 30 that form a single stator coil 20, but each type may only differ in details of shape and length. For example, one type of segment coil 30 may only have a difference in size corresponding to the difference in the radial position (which turn) in which the slot insertion portion 31 is inserted compared to other types of segment coils 30. 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. The tip 32a of each of the pair of connecting portions 322 is joined (connected) by welding to the tip 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 in which 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, assuming 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 also 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 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 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 portions 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 a pair of connecting parts 322A and 322B from the slot insertion parts 31 in two specific slots 13, but the same applies to a pair of connecting parts 322 from the slot insertion parts 31 in any other adjacent slots 13 in the circumferential direction. Furthermore, the following describes a pair of connecting parts 322A and 322B that are continuous from the slot insertion part 31 of the first turn, but the same applies to a pair of connecting parts 322 that are continuous from the slot insertion part 31 of the second turn, a pair of connecting parts 322 that are continuous from the slot insertion part 31 of the third turn, and so on. Also, the following describes a pair of connecting parts 322A and 322B that tilt towards C2, referring to Figure 3, but the same applies to a pair 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 of ​​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 relating 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 we let S0 be the cross-sectional area at the slot insertion portion 31, the following relationship holds true in this embodiment.

[0034] S0 > max(SA to SE) Here, max(SA to SE) is the maximum value from SA to 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, 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. That is, the cross-sectional area SC at the central part 321b of the oblique 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. That is, 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. When 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) is also smaller at the central part 321b of the slanted portion 32b than at both ends 321c and 321d. Of the two orthogonal sides forming the rectangular cross-section, the dimension that contributes to the axial size of the coil end (axial dimension) is the side that extends axially in the connecting portion 32 (an example of the "first side"), and the other side is the side that extends radially (an example of the "second side"). In this specification, a reduction in cross-sectional area means that both sides become smaller, but it may also mean that only the sides extending axially in the connecting portion 32 become smaller.

[0038] Next, we will outline an example of a manufacturing method for achieving the preferred cross-sectional area profile according to the above-described embodiment.

[0039] Figure 4 is an explanatory diagram of an example of a manufacturing method for realizing the cross-sectional area profile according to this embodiment.

[0040] The cross-sectional area profile according to the present embodiment described above with reference to FIG. 3 may be realized by any method. For example, it may be realized by joining conductor pieces (with insulating coatings) having corresponding cross-sectional areas. Preferably, it may also be realized by the method conceptually shown in FIG. 4. In the example shown in FIG. 4, a substantially U-shaped segment coil 30A which is a material for forming the segment coil 30 is shown. In this case, the segment coil 30A can be formed by bending in the circumferential direction starting from the vicinity P1 of the axial end of the slot insertion portion 31 (see arrow R41), then pulling outward in the axial direction (see arrow R42), and bending inward in the circumferential direction starting from the vicinity P2 of the outer circumferential end of the inclined portion 32b (see arrow R43). In this case, the stator core side curved portion 32c is formed by bending at the vicinity P1 of the axial end, and the tip side curved portion 32d is formed by bending at the vicinity P2 of the outer circumferential end in the circumferential direction.

[0041] As described above in detail for each embodiment, the present invention is not limited to a specific embodiment, and various modifications and changes are possible within the scope described in the claims. Also, it is possible to combine all or a plurality of the components of the above-described embodiments.

[0042] For example, in the above-described embodiment, the tip side curved portion 32d is provided, but the tip side curved portion 32d may be omitted. That is, it may be configured to extend linearly from the inclined portion 32b to the tip portion 32a.

[0043] Regarding each of the above-described embodiments, the following additional remarks are further disclosed.

[0044] On one side, the present disclosure aims to reduce the axial size of the coil end in a configuration where the coil end is formed by an overlapping portion that overlaps in the axial direction.

[0045] [Note 1] A stator for a rotating electric machine comprising a stator coil formed by a segment coil having a rectangular cross-section, and a stator core having a plurality of slots on which the stator coil is wound, wherein the stator coil has a slot insertion portion inserted into each corresponding slot among the plurality of slots, and a connecting portion exposed from the axial end face of the stator core and extending circumferentially in a manner that connects a pair of the slot insertion portions, wherein the connecting portions, which are continuous from each of the two slot insertion portions inserted at the same radial position of two adjacent slots in the circumferential direction, are bent in the same circumferential direction and overlap when viewed in the axial direction, and the cross-sectional area of ​​the connecting portion is smaller in the portion between the circumferential ends than at the circumferential ends of the oblique portion that extends obliquely in the axial outward and circumferential direction from the axial end face of the stator core. [Note 2] Each of the connecting portions on one side in the axial direction is formed by joining two connecting forming portions from a pair of slot insertion portions, and each of the two connecting forming portions has one of the oblique portions, as described in Note 1, for a stator for a rotating electric machine. [Note 3] The portion between the two ends in the circumferential direction includes the circumferential central portion of the oblique portion, as described in Note 2, for a stator for a rotating electric machine. [Note 4] Each of the portions between the two ends in the circumferential direction of a pair of connecting portions that overlap in the axial direction is located within the circumferential range of the pair of connecting portions that overlap in the axial direction, as described in any of Notes 1 to 3, for a stator for a rotating electric machine.

[0046] 100 Stator, 10 Stator core, 13 Slot, 30 Segment coil, 31 Slot insertion section, 32 Connecting section, 322 Connecting forming section, 32b Slanted section

Claims

1. A stator for a rotating electric machine comprising a stator coil formed by segment coils having a rectangular cross-section, and a stator core having a plurality of slots on 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 the slot insertion portions, and the cross-sectional area of ​​the connecting portions is smaller than the cross-sectional area of ​​the slot insertion portions.

2. The stator for a rotating electric machine according to claim 1, wherein each of the connecting portions on one side in the axial direction is formed by joining two connecting forming portions from a pair of slot insertion portions, and the connecting forming portions that are continuous from each of the two slot insertion portions inserted into the same radial position of two adjacent slots in the circumferential direction are bent in the same direction in the circumferential direction and partially overlap when viewed in the axial direction.

3. The stator for a rotating electric machine according to claim 1, wherein the connecting portion includes an oblique portion extending obliquely from the axial end face of the stator core outward in the axial direction and in the circumferential direction, and the cross-sectional area of ​​the oblique portion in the connecting portion is smaller than the cross-sectional area of ​​the slot insertion portion.

4. The stator for a rotating electric machine according to claim 3, wherein the cross-sectional area of ​​both circumferential ends of the slanted portion is smaller than the cross-sectional area of ​​the portion between the circumferential ends of the slanted portion.

5. The stator for a rotating electric machine according to claim 4, wherein 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, and each of the two connecting portions has one of the oblique portions.

6. The stator for a rotating electric machine according to claim 5, wherein the portion between both ends in the circumferential direction includes the central portion in the circumferential direction of the oblique portion.

7. The stator for a rotating electric machine according to claim 4, wherein each of the portions between the circumferential ends of a pair of overlapping connecting portions viewed in the axial direction is located within the circumferential range of the pair of overlapping connecting portions viewed in the axial direction.

8. The stator for a rotating electric machine according to any one of claims 1 to 7, wherein the two orthogonal sides forming the rectangular cross section consist of a first side extending axially in the connecting portion and a second side extending radially, and the length of the first side in the connecting portion is smaller than the length of the first side in the slot insertion portion.

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