Stator for rotating electric machine

Abstract

A stator of a rotating electrical machine includes a stator core having a plurality of slots, and a stator coil formed of segmented coils configured using flat wires having a rectangular cross-section and inserted into different slots separated in a circumferential direction of the stator core. The segment coil has a pair of insertion parts which are inserted into different slots, and a connection part which connects the pair of insertion parts to each other. When a slot pitch, which is the pitch between slots into which a pair of insertion portions of a segment coil are inserted, is Ns and the total number of slots in the stator core is S, the following relational expression (1) is satisfied: Ns < S / 4 (1).

Description

Technical Field

[0001] This disclosure relates to a stator of a rotating electric machine. Background Technology

[0002] In recent years, in the pursuit of increasingly smaller and higher-powered rotary motors for vehicle drives, stator windings are constructed using stator coils made of flat wires with rectangular cross-sections. Patent Document 1 describes a stator for a rotary motor in which six or more slot conductors are inserted into a single slot. The slot pitch of the jumper wires connecting the radially positioned windings spans the slots at at least two different pitches. When N is defined as the number of slots per pole, the different slot pitches of the jumper wires are N+1 and (N+1)±1. The stator has multiple groups of slot conductors, each consisting of multiple winding conductors of the same phase. These multiple winding conductors are inserted into slots arranged continuously in the circumferential direction of the stator core in a slot-and-layer-adjacent manner. When the number of slots per phase per pole is defined as NSPP, and the number of each phase of the (N+1)±1 slot pitch jumper wires is defined as 2×NJ, the specified number Ns satisfies the formula "Ns=NSPP+NJ". Summary of the Invention

[0003] The problem the invention aims to solve In rotary electrical machines as described in Japanese Patent No. 6513831, rotary electrical machines with various output ranges have been studied. In particular, for the purpose of rotary electrical machines with low output, the miniaturization of the stator core has been studied. In this case, if the number of slots in the stator core is reduced, the center angle of the coil end of the segmented coil becomes relatively larger when inserting the segmented coil into the slot, and the rigidity of the bent portion of the coil end decreases (i.e., it is easy to plastically deform). Therefore, there is a problem that it is difficult to insert the segmented coil through the coil end.

[0004] The technology disclosed herein provides a stator that can improve the productivity of stator coils even when the number of slots in a stator core using segmented coils is reduced.

[0005] means for solving problems The first aspect of the technology disclosed herein is a stator of a rotary electric machine, comprising: a stator core having a plurality of slots, and a stator coil formed of segmented coils, the segmented coils being constructed using flat wires with rectangular cross-sections and inserted into different slots separated in the circumferential direction of the stator core, the segmented coils having a pair of insertion portions inserted into different slots respectively and a connecting portion connecting the pair of insertion portions to each other; when the spacing between the slots into which the pair of insertion portions of the segmented coils are inserted is set to Ns, and the total number of slots in the stator core is set to S, the following relationship (1) is satisfied: Ns<S / 4(1).

[0006] In a second aspect of the technology disclosed herein, the stator of the rotary motor according to the first aspect has a slot pitch that is the slot pitch in the intermediate layer between the outermost and innermost circumferential layers of the stator core.

[0007] In a third aspect of the technology disclosed herein, the stator of the rotating electric motor according to the first aspect has P ≤ 4 when the number of magnetic poles of the rotor rotating relative to the stator is set to P.

[0008] In the fourth aspect of the technology disclosed herein, the stator of the rotating electric machine according to the first aspect has a total number of slots S=24 in the stator core.

[0009] Invention Effects According to the technology disclosed herein, a stator is provided that can improve the productivity of stator coils even when the number of slots in a stator core using segmented coils is reduced. Attached Figure Description

[0010] Figure 1A A perspective view of the stator of a rotary electric motor according to an embodiment.

[0011] Figure 1B A perspective view of the stator of a rotary electric motor according to an embodiment.

[0012] Figure 2 A perspective view showing a portion of the stator coils and stator core of the stator of the rotary electric machine according to an embodiment.

[0013] Figure 3 To show in magnified form Figure 2 A three-dimensional view of a portion of the structure shown.

[0014] Figure 4 This is a diagram illustrating an example of stator coil wiring.

[0015] Figure 5 This is a conceptual diagram illustrating an example of stator coil wiring in an embodiment.

[0016] Figure 6 A diagram illustrating an example of stator coil wiring in an embodiment.

[0017] Figure 7 A diagram illustrating an example of stator coil wiring in an embodiment. Detailed Implementation

[0018] The following is for reference Figures 1A to 5 The stator 10 of the rotary electric machine according to the first embodiment (hereinafter simply referred to as "stator 10") is explained. Furthermore, in each figure, there are instances where some reference numerals are omitted for ease of observation. For example... Figure 1A as well as Figure 1BAs shown, the stator 10 of this embodiment includes a stator core 12 and stator coils 19. This stator 10, together with a rotor (not shown, for example), constitutes a three-phase AC rotating motor. Furthermore, in Figure 1A as well as Figure 1B In the diagram, arrows Z, A, and D represent the circumferential, axial, and radial directions of the stator core 12, respectively. Hereinafter, the circumferential direction of the stator core 12 will sometimes be referred to as "circumferential," the axial direction of the stator core 12 as "axial," and the radial direction of the stator core 12 as "radial."

[0019] in, Figure 1A The stator coil 19 of the stator 10 shown is as described later. Figure 6 The coil wiring shown is used for routing. Additionally, Figure 1B The stator coil 19 of the stator 10 shown is as described later. Figure 7 The coil wiring shown is used for wiring.

[0020] The stator core 12 is formed by stacking multiple electromagnetic steel plates into a cylindrical shape. The stator core 12 has a yoke 14, multiple teeth 16, and multiple slots 18. The multiple teeth 16 and multiple slots 18 are arranged alternately in the circumferential direction on the inner circumferential side of the stator core 12. The multiple slots 18 are open on both sides in the axial direction and on the inner side in the radial direction.

[0021] like Figure 2 As shown, the stator coil 19 is configured to include a plurality of segmented coils 20. Each segmented coil 20 is formed in a generally U-shape from a flat wire with a rectangular cross-section, made of copper or the like. Each segmented coil 20 has a pair of parallel slot insertion portions 22, coil ends 24 connecting one end of each pair of slot insertion portions 22 to each other, and a pair of leads 26 extending from the other ends of the pair of slot insertion portions 22. The portion of the segmented coil 20 other than the front ends of the pair of leads 26 is covered with an insulating film. The coil ends 24 are an example of a "connecting portion" in the present disclosure. The pair of slot insertion portions 22 are an example of a "pair of insertion portions" in the present disclosure.

[0022] A pair of slot inserts 22 are inserted from one axial side into different slots 18 that are circumferentially separated in the stator core 12. Coil ends 24 are disposed outside the slots 18 on one axial side of the stator core 12, connecting one end of the pair of slot inserts 22 to each other circumferentially. Figure 1A as well as Figure 1B As shown, multiple segmented coils 20 are overlapped in multiple layers and arranged in a circular ring in the radial direction of the stator core 12. A pair of leads 26 of each segmented coil 20 protrude from the end face on the opposite side of the axial direction of the stator core 12. These leads 26 are twisted to engage with the leads 26 of other segmented coils 20.

[0023] In the following description, in the stator core 12, the side where the coil end 24 of the segmented coil 20 is located is referred to as the turn side, and the side where the lead-out portion 26 of the segmented coil 20 is located is referred to as the welding side. Furthermore, the joining method of the lead-out portions 26 is not limited to welding, but may also be other joining methods (e.g., ultrasonic joining, friction welding, mechanical fastening).

[0024] The segmented coils 20 are formed as a continuous winding, called a wave winding, around the entire circumference of the stator core 12. In other words, the segmented coils 20 are wired along the circumference of the stator core 12 through the wave winding, and the segmented coils 20 are electrically connected to each other, thereby forming the stator coils 19.

[0025] like Figure 3 As shown, from a radial perspective, the coil ends 24 of the segmented coil 20 are formed in a generally V-shape or a generally U-shape. Figure 4 From the axial perspective shown, the coil end 24 is bent into an arc shape along the circumferential direction. The coil end 24 has two curved portions 24A extending circumferentially in the axial perspective, and a crank portion 24B disposed between the two curved portions 24A and connecting them. The crank portion 24B is bent into a crank shape such that the two curved portions 24A are radially offset. The two curved portions 24A are configured to be approximately the thickness of a flat wire that is radially offset from each other.

[0026] like Figure 1A as well as Figure 1B As shown, the slot insertion portions 22 of multiple segmented coils 20 are sequentially inserted into each slot 18, offset circumferentially by one slot 18 of the stator core 12, and inserted in one revolution, thereby forming one layer. In this embodiment, three layers of segmented coils 20 are formed. Moreover, the circumferential length of each layer of segmented coils 20 is slightly different depending on the radial position of each layer.

[0027] Furthermore, rotary motors require various output ranges. In particular, in the development of low-output rotary motors for applications such as small automobiles, miniaturization of the stator core 12 is being studied. In this case, there is a reduction in the number of slots in the stator core 12 (for example, a 4-pole, 24-slot configuration). In the case of a small rotary motor, if the segmented coil 20 is to be inserted into the slot, the center angle of the coil end 24 of the segmented coil 20 becomes relatively larger, and the rigidity of the bent portion 24A of the coil end 24 decreases (i.e., it is prone to plastic deformation), making it difficult to insert the segmented coil 20 through the coil end 24.

[0028] Figure 4 This is a conceptual diagram illustrating the bending shape of the coil end 24. For clarity, it shows a segmented coil 20 inserted into two circumferentially separated slots 18 of the stator core 12; in reality, multiple segmented coils are inserted into their respective slots 18. Figure 4 As shown on the left, in the stator core 12, the segmented coil 20 becomes relatively longer. If the slot 18 into which the segmented coil 20 is inserted is configured to be separated by more than 90 degrees, the rigidity of the bent portion 24A at the coil end 24 decreases, making it difficult to insert the segmented coil 20. On the other hand, through in-depth research by the inventors of this invention, it was discovered that... Figure 4 As shown on the right, if the slots 18 into which the segmented coil 20 is inserted are at an angle smaller than 90 degrees (e.g., 75 degrees), they are easy to insert.

[0029] Therefore, in the stator coil 19 of this embodiment, on the turning side, the slot pitch Ns and the total number of slots S have the following relationship (1).

[0030] Ns<S / 4(1) The slots 18 are evenly arranged along the circumference of the stator core 12. Therefore, the number of slots arranged per 90 degrees is obtained by dividing the total number of slots S by 4. In addition, the slot pitch Ns is the number of slots 18 that the segmented coil 20 spans. That is, the number of slots 18 from the next slot 18 inserted in one of the slot insertion portions 22 of the segmented coil 20 to the slot 18 inserted in the other slot insertion portion 22. Therefore, as described in the above relationship (1), by setting the slot pitch Ns to a value smaller than the total number of slots S divided by 4, the decrease in rigidity of the bent portion 24A of the coil end 24 of the segmented coil 20 can be suppressed.

[0031] like Figure 5 As shown, in the stator coil 19 of this embodiment, the number of rotor poles P=4, and the total number of slots S=24 (i.e., 4 poles and 24 slots). Figure 5 The diagram shows only the wiring of the segmented coil 20 corresponding to one phase (e.g., phase U) of the three-phase AC current flowing through the stator coil 19.

[0032] Furthermore, the slot pitch Ns = 5. As an example, the slot number 1 of layer No. 2 in the middle layer ML on the turning side and the slot number 6 of the outermost layer OL are inserted into the same segmented coil 20. That is, there are five slots 18 from the next slot number 2 after the slot number 1 into which the segmented coil 20 is inserted to the slot number 6 into which the same segmented coil 20 is inserted.

[0033] In the stator coil 19 of this embodiment, regarding the slot pitch Ns, in any layer of the outermost peripheral layer OL on the turning side, the innermost peripheral layer IL on the turning side, and the intermediate layer between the outermost peripheral layer OL and the innermost peripheral layer IL on the turning side, the slot pitch Ns is Ns=5. Moreover, the slot pitch satisfies Ns=5<S / 4 (=24 / 4=6).

[0034] The outermost layer OL is a collection (i.e., a segmented coil group) of segmented coils 20 arranged radially on the outermost periphery of the stator core 12 in the plurality of slots 18. The innermost layer IL is a collection of segmented coils 20 arranged radially on the innermost periphery of the stator core 12 in the plurality of slots 18. The intermediate layer ML is a collection of segmented coils 20 arranged between the outermost layer OL and the innermost layer IL.

[0035] Thus, in the stator coil 19 of this embodiment, the slot pitch Ns is set to satisfy the above relationship (1), and the segmented coil 20 is wired.

[0036] (Function and effect) As described above, in the stator core 12 of this embodiment, by setting the slot pitch Ns to satisfy the above-described relationship (1), deformation of the coil ends 24 of the segmented coils 20 can be suppressed, making it easier to insert the segmented coils 20 into the stator core 12. As a result, the productivity of the stator core 12 is improved.

[0037] For example, in low-output applications such as light-duty and small cars, the requirements for combinations of slot and pole number suitable for small rotating motors with 4 poles and 24 slots are increasing. However, if the number of slots decreases, the coil end 24 of the segmented coil 20 becomes relatively longer relative to the slot pitch Ns. For example, compared to the combinations of pole and slot number seen in conventional high-power applications with 8 poles and 48 slots or 12 poles and 72 slots, reducing the number of slots results in a relatively longer coil end 24. Therefore, when the segmented coil 20 is inserted into the slot 18, the coil end 24 becomes arched circumferentially, deforming significantly, making it difficult to insert the segmented coil 20 into the slot 18. As a result, the productivity of the stator core 12 decreases. In this structure, as described above, because the slot pitch Ns is formed in a predetermined relationship with the total number of slots, the deformation of the coil end 24 is suppressed, making the insertion of the segmented coil 20 easier. For example, even with a reduction in the number of slots in the stator core using segmented coils, the operation of inserting segmented coils 20 becomes easier, thus increasing the productivity of the stator core 12.

[0038] Furthermore, in the stator core 12 of this embodiment, the number of magnetic poles is 4. Generally, in the case of a rotor with a magnetic pole displacement of 4 or less, the aforementioned technical problems are particularly prone to occur in the corresponding stator core 12. In this structure, as described above, because the slot pitch Ns is formed in a predetermined relationship with respect to the total number of slots, deformation of the coil ends 24 is also suppressed in the stator core 12 corresponding to a rotor with a magnetic pole number of 4, making the insertion of the segmented coils 20 easier.

[0039] Furthermore, in the stator core 12 of this embodiment, the total number of slots is 24. Generally, the aforementioned technical problems are particularly prone to occur when the stator core 12 has a total of 24 slots. In this structure, as described above, because the slot pitch Ns is formed in a predetermined relationship with respect to the total number of slots, deformation of the coil ends 24 is also suppressed in the stator core 12 corresponding to a rotor with 4 magnetic poles, making the insertion of the segmented coils 20 easier.

[0040] Furthermore, in the above embodiments, an example of a rotor with 4 magnetic poles is given and described, but the technology disclosed herein is not limited to this. The number of magnetic poles P can be ≤ 4, for example, the number of magnetic poles P can also be 2.

[0041] (Variation Example 1) In addition, such as Figure 6 As shown, in other wiring examples of the stator core 12 in this embodiment, the slot pitch Ns = 5 in the 4 poles and 24 slots. As an example, the same segmented coil 20 is inserted into the slot number 1 of layer No. 3 and the slot number 6 of layer No. 2 of the intermediate layer ML on the turning side. Moreover, the slot pitch Ns = 5 < S / 4 (= 24 / 4 = 6) is satisfied.

[0042] Additionally, as an example, slots numbered 2 and 7 of the outermost circumferential layer OL on the turning side are inserted into the same segmented coil 20. Moreover, the slot pitch Ns = 5 < S / 4 (= 24 / 4 = 6).

[0043] Additionally, as an example, slots numbered 1 and 6 of the innermost circumferential layer IL on the turning side are inserted into the same segmented coil 20. Moreover, the slot pitch Ns = 5 < S / 4 (= 24 / 4 = 6).

[0044] Thus, in the stator coil 19 of this modified example, regarding the slot pitch Ns, in any layer of the outermost peripheral layer OL on the turning side, the innermost peripheral layer IL on the turning side, and the intermediate layer between the outermost peripheral layer OL and the innermost peripheral layer IL on the turning side, the slot pitch Ns is Ns=5. Moreover, it satisfies that the slot pitch Ns=5<S / 4 (=24 / 4=6). Therefore, in the stator core 12 of this modified example, the same effect as in the above embodiment can also be obtained.

[0045] (Variation Example 2) Furthermore, in the above embodiments, regarding the slot pitch Ns, examples of ways that satisfy the above relation (1) are given and described in any one of the outermost peripheral layer OL on the turning side, the innermost peripheral layer IL on the turning side, and the intermediate layer ML between the outermost peripheral layer OL and the innermost peripheral layer IL on the part side, but the technology disclosed herein is not limited thereto.

[0046] As an example, such as Figure 7As shown, in this modified example, within the intermediate layer ML on the turning side, the above relationship (1) is satisfied. Figure 6 In the example shown, the slot pitch Ns of the intermediate layer ML is 5. As an example, on the turning side, slot 1 of layer No. 3 and slot 6 of layer No. 2 of the intermediate layer ML are inserted into the same segmented coil 20.

[0047] On the other hand, setting the slot pitch Ns of the outermost layer OL and the innermost layer IL to 6 does not satisfy the above relationship (1). In other words, only the slot pitch Ns in the middle layer ML satisfies the above relationship (1).

[0048] As described above, in this modified example, by setting the slot pitch Ns of the intermediate layer ML to satisfy the above relationship (1), the deformation of the coil end 24 of the segmented coil 20 is suppressed, making it easier to insert the segmented coil 20 into the stator core 12. As a result, the productivity of the stator core 12 is improved.

[0049] Generally, the aforementioned technical problems are particularly prone to occur when inserting segmented coils 20 into slots 18 of the intermediate layer ML of the stator core 12. In this structure, as described above, by setting the slot pitch Ns of the intermediate layer ML to satisfy the above relationship (1), the operation of inserting segmented coils becomes easier.

[0050] Furthermore, in this embodiment, the segmented coil 20 is made of flat wire, which is a metal wire with a rectangular cross-section. However, it is not limited to this; the stator coil 19 may also be made of flat wire with a rectangular cross-section, which may be composed of multiple single conductors. In addition, in this embodiment, the stator core 12 is made of laminated steel plates. However, it is not limited to this; the stator core 12 may also be at least partially made of pressed powder magnetic core.

[0051] In addition, in this embodiment, the stator coil 19 can be a so-called waveform winding that is continuously wound around the entire circumference of the stator core 12.

[0052] The foregoing description and accompanying drawings provide a detailed explanation of the technical aspects of this disclosure and are merely one example. For instance, the above description of structure, function, effect, and impact is just one example of the structure, function, effect, and impact of the technical aspects of this disclosure. Therefore, it is self-evident that, without departing from the spirit of this disclosure, unnecessary parts of the foregoing description and accompanying drawings can be deleted, or new elements can be added or replaced. Furthermore, to avoid confusion and facilitate understanding of the technical aspects of this disclosure, information regarding technical common sense that does not require special explanation in implementing the technology of this disclosure has been omitted from the foregoing description and accompanying drawings.

[0053] All documents, patent applications and technical specifications described herein, and to the same extent that each document, patent application and technical specification is specifically and separately referenced herein, are incorporated herein by reference.

[0054] Furthermore, the disclosure of Japanese Patent Application No. 2023-124989, filed on July 31, 2023, is incorporated herein by reference in its entirety.

Claims

1. A stator of a rotary electric machine, wherein, has: a stator core having a plurality of slots, and a stator coil formed of segment coils constituted using flat wire having a rectangular cross section and inserted into different slots separated in a circumferential direction of the stator core, the segment coils having a pair of insertion portions respectively inserted into different slots and a linking portion linking the pair of insertion portions to each other; where a slot pitch, which is a distance between the slots into which the pair of insertion portions of the segment coil is inserted, is set to Ns, and a total number of slots of the stator core is set to S, the following relation (1) is satisfied: Ns < S / 4 (1).

2. The stator of a rotary electric machine according to claim 1, wherein the slot pitch is the slot pitch of an intermediate layer between an outermost circumferential layer and an innermost circumferential layer of the stator core.

3. The stator of a rotary electric machine according to claim 1, wherein where a number of magnetic poles of a rotor rotating relative to the stator is set to P, P < 4.

4. The stator of a rotary electric machine according to claim 1, wherein the total number of slots S of the stator core = 24.

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