Stator core and rotary electric machine provided with same

Abstract

This stator core is provided with a plurality of electromagnetic steel sheets stacked in the axial direction. The plurality of electromagnetic steel sheets include at least one first electromagnetic steel sheet stacked from one end in the axial direction, and at least one second electromagnetic steel sheet stacked on the at least one first electromagnetic steel sheet. The at least one second electromagnetic steel sheet has a non-overlapping region that does not overlap the at least one first electromagnetic steel sheet in the axial direction. The at least one second electromagnetic steel sheet includes an adjacent electromagnetic steel sheet adjacent to the at least one first electromagnetic steel sheet. The non-overlapping region of the adjacent electromagnetic steel sheet is configured such that a fixture for fixing the stator core contacts the non-overlapping region.

Description

Stator Core and Rotating Electric Machine Comprising the Same Cross-Reference to Related Applications

[0001] This application is a related application of Japanese Patent Application No. 2025-006701 filed on January 17, 2025, claims the priority based on this Japanese patent application, and incorporates all the contents described in this Japanese patent application as constituting this specification.

[0002] The technology disclosed in this specification relates to a stator core and a rotating electric machine comprising the same.

[0003] Japanese Unexamined Patent Application Publication No. 2007-221853 discloses a stator core used in a rotating electric machine. The stator core includes a plurality of electromagnetic steel sheets laminated in the axial direction.

[0004] The stator core is fixed to the case of the rotating electric machine by a fixture. Such a fixture is often a fastening tool such as a bolt. The bolt is inserted into a bolt hole penetrating the stator core in the axial direction to fasten the stator core to the case.

[0005] An axial compressive force acts on the plurality of electromagnetic steel sheets constituting the stator core by a fixture. This compressive force may cause deformation such as curling in one or more electromagnetic steel sheets arranged at one end in the axial direction among the plurality of electromagnetic steel sheets constituting the stator core. This specification provides a technology capable of suppressing the deformation of the plurality of electromagnetic steel sheets constituting the stator core.

[0006] One embodiment of a stator core disclosed herein may comprise a plurality of electromagnetic steel sheets laminated in the axial direction. The plurality of electromagnetic steel sheets may include at least one first electromagnetic steel sheet laminated from one end in the axial direction, and at least one second electromagnetic steel sheet laminated from at least one first electromagnetic steel sheet. At least one second electromagnetic steel sheet may have a non-overlapping region that does not overlap with at least one first electromagnetic steel sheet in the axial direction. At least one second electromagnetic steel sheet may have an adjacent electromagnetic steel sheet adjacent to at least one first electromagnetic steel sheet. The non-overlapping region of the adjacent electromagnetic steel sheet may be configured to be in contact with a fastener that fixes the stator core. In this stator core, the fastener applies a compressive force to at least one second electromagnetic steel sheet by contacting the non-overlapping region of the adjacent electromagnetic steel sheet, while not applying a compressive force to at least one first electromagnetic steel sheet, or not applying an excessive compressive force to it. This makes it possible to suppress deformation of the plurality of electromagnetic steel sheets constituting the stator core.

[0007] One embodiment of a stator core disclosed herein may comprise a plurality of electromagnetic steel sheets laminated in the axial direction. The plurality of electromagnetic steel sheets may include at least one first electromagnetic steel sheet laminated from one end in the axial direction, and at least one second electromagnetic steel sheet laminated from at least one first electromagnetic steel sheet. At least one first electromagnetic steel sheet may be configured such that no axial compressive force is acted upon it by a fastener that secures the stator core, or such that the axial compressive force from the fastener is less than the compressive force acting on at least one second electromagnetic steel sheet. In this stator core, deformation of the plurality of electromagnetic steel sheets constituting the stator core can be suppressed.

[0008] One embodiment of a rotating electric machine disclosed herein may include a stator core comprising a plurality of electromagnetic steel sheets stacked in the axial direction, and a fixture for fixing the stator core. The plurality of electromagnetic steel sheets may include at least one first electromagnetic steel sheet stacked from one end in the axial direction, and at least one second electromagnetic steel sheet stacked from at least one first electromagnetic steel sheet. At least one second electromagnetic steel sheet may have a non-overlapping region that does not overlap with at least one first electromagnetic steel sheet in the axial direction. At least one second electromagnetic steel sheet may have an adjacent electromagnetic steel sheet adjacent to at least one first electromagnetic steel sheet. The fixture may be in contact with the non-overlapping region of the adjacent electromagnetic steel sheet. In this rotating electric machine, the fixture applies a compressive force to at least one second electromagnetic steel sheet, while not applying a compressive force, or not applying an excessive compressive force, to at least one first electromagnetic steel sheet. This makes it possible to suppress deformation of the plurality of electromagnetic steel sheets constituting the stator core.

[0009] This is a schematic top view of the stator core of this embodiment.

[0010] This is an enlarged schematic top view of the vicinity of the protruding portion of the stator core of this embodiment.

[0011] This is a schematic cross-sectional view of the main part of the rotating electric machine of this embodiment, and it corresponds to the schematic cross-sectional view of the main part along line III-III in Figure 1.

[0012] This is a schematic top view of one modified example of the stator core of this embodiment.

[0013] This is a schematic cross-sectional view of the main part of the rotating electric machine of this embodiment, and is a schematic cross-sectional view of the main part corresponding to the VV line in Figure 4.

[0014] This is a schematic cross-sectional view of a key part of a modified example of the rotating electric machine of this embodiment.

[0015] This is a schematic cross-sectional view of a key part of a modified example of the rotating electric machine of this embodiment.

[0016] The stator core 10 and the rotating electric machine 100 on which the stator core 10 is mounted will be described below with reference to the drawings. Here, a cylindrical coordinate system consisting of axial, radial, and circumferential directions is defined with reference to the cylindrical stator core 10. The z-axis shown in the figure is an axis parallel to the central axis CA of the stator core 10 and indicates the axial direction of the stator core 10. In this specification, the positive direction of the z-axis is referred to as one side of the axial direction, and the negative direction of the z-axis is referred to as the other side of the axial direction. The r-axis shown in the figure is perpendicular to the z-axis and indicates the radial direction of the stator core 10. In this specification, the direction away from the central axis CA along the r-axis is referred to as the radially outward direction, and the direction approaching the central axis CA along the r-axis is referred to as the radially inward direction. The θ-axis shown in the figure is perpendicular to the z-axis and r-axis and indicates the circumferential direction of the stator core 10.

[0017] As shown in Figures 1 and 2, the stator core 10 comprises a yoke portion 20, a plurality of teeth portions 22 projecting radially inward from the inner circumferential surface of the yoke portion 20, and a plurality of protrusions 24 projecting radially outward from the outer circumferential surface of the yoke portion 20. The yoke portion 20 is a cylindrical member with a central axis CA. Each of the plurality of teeth portions 22 extends from one end to the other end of the yoke portion 20 along the axial direction and is spaced apart from each other along the circumferential direction. Slots SL are formed between adjacent teeth portions 22 in the circumferential direction. Each of the plurality of protrusions 24 extends from one end to the other end of the yoke portion 20 along the axial direction. Each of the plurality of protrusions 24 is not particularly limited, but for example, they are spaced equally apart in the circumferential direction. In this example, a stator core 10 provided with four protrusions 24 is illustrated. Alternatively, the stator core 10 may have fewer than four protrusions 24, or more than four protrusions 24. Furthermore, the stator core 10 may have an even number of protrusions 24, or an odd number of protrusions 24.

[0018] As shown in Figure 3, coils 30 are attached to a plurality of slots SL of the stator core 10. The coils 30 have a pair of coil ends 32 that protrude from both ends of the stator core 10 in the axial direction. The coils 30 are not particularly limited, but may be composed of a plurality of segment coils, for example. Each of the plurality of segment coils is a flat rectangular wire formed by coating the surface of a conductor with an insulator, and is a substantially U-shaped member. The coils 30 are formed by inserting each of the plurality of segment coils into the slots SL of the stator core 10 along the axial direction, and then bending both ends of the substantially U-shape.

[0019] As shown in Figure 3, the stator core 10 comprises a plurality of electromagnetic steel sheets 12 stacked in the axial direction. Adjacent electromagnetic steel sheets 12 may be joined by, for example, adhesive, riveting, welding, or a combination thereof, although this is not particularly limited. The plurality of electromagnetic steel sheets 12 comprises a plurality of first electromagnetic steel sheets 12A stacked from one end in the axial direction, and a plurality of second electromagnetic steel sheets 12B stacked from the plurality of first electromagnetic steel sheets 12A. Among the plurality of second electromagnetic steel sheets 12B, the second electromagnetic steel sheets 12B adjacent to the first electromagnetic steel sheets 12A are specifically referred to as adjacent electromagnetic steel sheets 14. Thus, the stator core 10 in this example is composed of two types of electromagnetic steel sheets. The first electromagnetic steel sheets 12A comprising the stator core 10 may be a plurality or a single sheet. Hereinafter, when simply referred to as "electromagnetic steel sheet 12", the electromagnetic steel sheet 12 is intended to include both the first electromagnetic steel sheet 12A and the second electromagnetic steel sheet 12B.

[0020] A through-hole 26 is formed in the portion of the stator core 10's protruding portion 24 that is composed of multiple first electromagnetic steel sheets 12A, extending axially. The through-hole 26 is circular when viewed from the axial direction. Alternatively, the through-hole 26 may have any shape when viewed from the axial direction, such as a polygon like a hexagon or octagon. The multiple second electromagnetic steel sheets 12B have non-overlapping regions 16 that do not overlap with the multiple first electromagnetic steel sheets 12A in the axial direction. In other words, the non-overlapping regions 16 of the multiple second electromagnetic steel sheets 12B can also be said to be regions that overlap with the through-hole 26 in the axial direction. Bolt holes 28 are formed in the non-overlapping regions 16 of the multiple second electromagnetic steel sheets 12B, extending axially. The bolt holes 28 are circular when viewed from the axial direction. The diameter of the through-hole 26 is larger than the diameter of the bolt holes 28. Thus, the first electrical steel sheet 12A and the second electrical steel sheet 12B are distinguished by the presence of large-diameter through holes 26 and small-diameter bolt holes 28.

[0021] The stator core 10 is fixed to the case 50 of the rotating electric machine 100 by fasteners. In this example, the fasteners are bolts 40. The bolts 40 are inserted through holes 26 in multiple first electromagnetic steel sheets 12A and into bolt holes 28 in multiple second electromagnetic steel sheets 12B. The case 50 has threaded holes 52 that extend in the axial direction. The threaded portion of the bolt 40 inserted into the bolt hole 28 is screwed into the threaded hole 52. In this way, the bolts 40 fasten the stator core 10 to the case 50.

[0022] The through holes 26 in the multiple first electrical steel sheets 12A are sized to allow the heads 42 of the bolts 40 to pass through. That is, the diameter of the through holes 26 in the multiple first electrical steel sheets 12A is larger than the maximum diameter of the heads 42 of the bolts 40. Therefore, the heads 42 of the bolts 40 are located inside the through holes 26 and do not come into contact with the multiple first electrical steel sheets 12A. As a result, the axial compressive force from the bolts 40 does not act on the multiple first electrical steel sheets 12A. On the other hand, the bolt holes 28 in the multiple second electrical steel sheets 12B are sized so that the heads 42 of the bolts 40 cannot pass through. That is, the diameter of the bolt holes 28 in the multiple second electrical steel sheets 12B is smaller than the maximum diameter of the heads 42 of the bolts 40. Therefore, the seating surface of the heads 42 of the bolts 40 is in contact with the adjacent electrical steel sheets 14 of the multiple second electrical steel sheets 12B. As a result, the axial compressive force from the bolts 40 acts on the multiple second electrical steel sheets 12B. The head 42 of the bolt 40 refers to the portion including the washer 44 if one is used, and is a structure that includes the portion that contacts the fastened member (in this example, multiple second electromagnetic steel sheets 12B) in the axial direction.

[0023] Here, we consider a comparative example in which bolt holes 28 are formed in multiple first electrical steel sheets 12A instead of through holes 26. In the comparative example, the seating surface of the head 42 of the bolt 40 is in contact with the electrical steel sheet 12 located on one end face in the axial direction. In this case, the teeth portion 22 of one or more electrical steel sheets 12 constituting the end on one end in the axial direction may be subject to deformation, such as curling, due to axial compressive force.

[0024] On the other hand, in the stator core 10 of this embodiment, no axial compressive force from the bolts 40 acts on the plurality of first electromagnetic steel sheets 12A that constitute one end in the axial direction. Therefore, deformation is suppressed in the plurality of first electromagnetic steel sheets 12A. However, axial compressive force from the bolts 40 acts on the plurality of second electromagnetic steel sheets 12B. However, since at least one first electromagnetic steel sheet 12A is laminated on the plurality of second electromagnetic steel sheets 12B, deformation of the plurality of second electromagnetic steel sheets 12B is restricted. Therefore, deformation is suppressed in both the plurality of first electromagnetic steel sheets 12A and the plurality of second electromagnetic steel sheets 12B. As a result, deterioration of magnetic properties due to deformation is suppressed in the rotating electric machine 100 of this embodiment.

[0025] As shown in Figure 3, in the above embodiment, the thickness 12T measured along the axial direction of the plurality of first electrical steel sheets 12A is greater than the thickness measured along the axial direction of the head 42 of the bolt 40. In other words, the top surface of the head 42 of the bolt 40 is located below the first electrical steel sheet 12A located on one end face in the axial direction, and the head 42 of the bolt 40 is contained within the through-hole 26 of the plurality of first electrical steel sheets 12A. For example, a wiring module, such as a busbar module, for electrically connecting to the coil 30 may be installed on the yoke portion 20 of the stator core 10. For example, if the head 42 of the bolt 40 protrudes axially from the through-hole 26, it is necessary to install the wiring module so as to avoid the head 42 of the bolt 40. This reduces the degree of freedom regarding the placement of the wiring module. On the other hand, in the above embodiment, the head 42 of the bolt 40 is contained within the through-hole 26 and does not interfere with the wiring module. Therefore, in the above embodiment, there is a high degree of freedom regarding the placement of the wiring module.

[0026] In the above embodiment, both the entire through-hole 26 and the entire bolt hole 28 were located on the protruding portion 24. Alternatively, a portion of the through-hole 26 and a portion of the bolt hole 28 may be located on the yoke portion 20. This example also has the effect of suppressing deformation occurring in the multiple electrical steel sheets 12.

[0027] In the above embodiment, the multiple first electromagnetic steel sheets 12A each had a protrusion 24, and through holes 26 were provided in the protrusion 24. Alternatively, as shown in Figures 4 and 5, the multiple first electromagnetic steel sheets 12A may not have protrusions 24. This example also has the effect of suppressing deformation occurring in the multiple electromagnetic steel sheets 12.

[0028] As shown in Figure 6, the rotating electric machine 100 may further include a refrigerant passage 60 extending in the axial direction. Lubricating oil is supplied as a refrigerant to the refrigerant passage 60. The refrigerant passage 60 is not particularly limited, but may be provided, for example, along the inner circumferential surface of the case 50, or it may be provided inside the case 50. The refrigerant passage 60 has a discharge port 62 for discharging refrigerant toward the coil end 32. The discharge port 62 is positioned radially outward from the coil end 32.

[0029] In this example, the rotating electric machine 100 is installed and used so that its axial direction is parallel to the horizontal direction, that is, its radial direction is parallel to the vertical direction. Therefore, the refrigerant discharged from the discharge port 62 of the refrigerant flow path 60 is supplied to the coil end 32 by free fall. In this example, the heads 42 of the bolts 40 are not arranged in a straight line connecting the discharge port 62 of the refrigerant flow path 60 and the coil end 32. In particular, in this example, the heads 42 of the bolts 40 are completely contained within the through holes 26 of the multiple first electromagnetic steel sheets 12A, and do not obstruct the fall path of the refrigerant supplied from the discharge port 62 toward the coil end 32. Therefore, the refrigerant discharged from the discharge port 62 is efficiently supplied to the coil end 32. As a result, the rotating electric machine 100 can have high cooling efficiency. Note that the heads 42 of the bolts 40 are not completely contained within the through holes 26 of the multiple first electromagnetic steel sheets 12A, and a part of the heads 42 of the bolts 40 may protrude from the through holes 26 of the multiple first electromagnetic steel sheets 12A. Even in this case, the rotating electric machine 100 can have high cooling efficiency as long as the head 42 of the bolt 40 is not positioned in a straight line connecting the discharge port 62 of the refrigerant flow path 60 and the coil end 32.

[0030] In the above embodiment, adjacent electrical steel sheets 12 are joined by, for example, adhesive, riveting, welding, or a combination thereof. As a result, although no axial compressive force is applied by the bolts 40, the laminated state of the multiple first electrical steel sheets 12A is maintained. To better maintain the laminated state of the multiple first electrical steel sheets 12A, the stator core 10 may be configured such that a compressive force weaker than the compressive force acting on the multiple second electrical steel sheets 12B is applied to the multiple first electrical steel sheets 12A.

[0031] For example, as shown in Figure 7, a stepped bolt 140 may be used. The head 142 of the stepped bolt 140 is in contact not only with the adjacent electrical steel sheet 14 but also with the first electrical steel sheet 12A located on one end face in the axial direction. The head 142 of the stepped bolt 140 has a bearing surface including the first washer 144 that is in contact with the adjacent electrical steel sheet 14, and a bearing surface including the second washer 146 that is in contact with the first electrical steel sheet 12A. For example, by adjusting the material and thickness of the first washer 144 and the second washer 146, a compressive force weaker than the compressive force acting on the multiple second electrical steel sheets 12B can be applied to the multiple first electrical steel sheets 12A. By reducing the compressive force acting on the multiple first electrical steel sheets 12A, the laminated state of the multiple first electrical steel sheets 12A can be maintained more favorably while suppressing the occurrence of deformation.

[0032] In the above embodiment, an example in which bolts are used as fasteners was described. Various fastening mechanisms can be used as fasteners that can press the stator core 10 in the axial direction and fix the stator core 10 to the case 50 of the rotating electric machine 100. For example, in an example in which bolt holes 28 are not formed in the second electromagnetic steel sheet 12B, a pressing device that presses multiple second electromagnetic steel sheets 12B in the axial direction in contact with adjacent electromagnetic steel sheets 14 may be used as a fastener. Regardless of which fastening mechanism is used as a fastener, the stator core 10 is pressed in the axial direction by the fastener, and the stator core 10, which is positioned between the fastener and the case 50 of the rotating electric machine 100, is fixed to the case 50 of the rotating electric machine 100. When the stator core 10 is pressed in the axial direction by the fastener, a compressive force acts on the stator core 10 in the axial direction. The technology disclosed herein makes it possible to suppress deformation of the multiple first electrical steel sheets 12A by not applying compressive force to the multiple first electrical steel sheets 12A, or not applying excessive compressive force to the multiple first electrical steel sheets 12A, regardless of which fixing mechanism is employed in the fixing device.

[0033] In the above embodiment, an example was described in which the deformation of one or more electromagnetic steel sheets 12 located at one end of the plurality of electromagnetic steel sheets 12 in the axial direction is suppressed. Instead of this example, or in addition to this example, the stator core 10 may be configured to suppress the deformation of one or more electromagnetic steel sheets 12 located at the other end of the plurality of electromagnetic steel sheets 12 in the axial direction. For example, one or more electromagnetic steel sheets 12 stacked from the other end in the axial direction do not have protrusions 24. As a result, one or more electromagnetic steel sheets 12 located at the other end in the axial direction do not come into contact with the case 50. As a result, the deformation of one or more electromagnetic steel sheets 12 located at the other end in the axial direction is suppressed.

[0034] The embodiments disclosed herein are summarized below. Note that the technical elements described below are independent technical elements that exhibit technical usefulness individually or in various combinations.

[0035] (Aspect 1) A stator core comprising a plurality of electromagnetic steel sheets stacked in the axial direction, wherein the plurality of electromagnetic steel sheets include at least one first electromagnetic steel sheet stacked from one end in the axial direction and at least one second electromagnetic steel sheet stacked from the at least one first electromagnetic steel sheet, wherein the at least one second electromagnetic steel sheet has a non-overlapping region that does not overlap with the at least one first electromagnetic steel sheet in the axial direction, and the at least one second electromagnetic steel sheet has an adjacent electromagnetic steel sheet adjacent to the at least one first electromagnetic steel sheet, wherein the non-overlapping region of the adjacent electromagnetic steel sheet is configured to be in contact with a fastener for fixing the stator core.

[0036] (Aspect 2) The stator core according to aspect 1, wherein at least one of the first electrical steel sheets is configured so that the fastener does not come into contact with it.

[0037] (Aspect 3) The stator core according to aspect 1 or 2, wherein a bolt hole penetrating in the axial direction is provided in the non-overlapping region of at least one second electrical steel sheet, the bolt hole is configured to allow a bolt of the fastener to be inserted through it, and the non-overlapping region of the adjacent electrical steel sheet is configured to be in contact with the seating surface of the head of the bolt inserted into the bolt hole.

[0038] (Aspect 4) The stator core according to aspect 3, wherein at least one second electrical steel sheet has a second electrical steel sheet projection that protrudes radially outward, and at least a portion of the bolt holes is located on the second electrical steel sheet projection.

[0039] (Aspect 5) The stator core according to aspect 4, wherein the entire bolt hole is located on the second electromagnetic steel sheet projection.

[0040] (Aspect 6) The stator core according to aspect 4 or 5, wherein the at least one first electromagnetic steel sheet also has a first electromagnetic steel sheet projection that protrudes radially outward, the at least one first electromagnetic steel sheet has a through hole that penetrates in the axial direction and has a larger diameter than the bolt hole, at least a portion of the through hole is arranged in the first electromagnetic steel sheet projection, and the bolt hole is arranged in the through hole in the axial direction.

[0041] (Aspect 7) The at least one first electromagnetic steel sheet has a through hole that penetrates in the axial direction and has a larger diameter than the bolt hole, and the bolt hole is disposed within the through hole in the axial direction. The stator core according to Aspect 3.

[0042] (Aspect 8) The thickness of the at least one first electromagnetic steel sheet is larger than the thickness of the head of the bolt inserted through the bolt hole. The stator core according to any one of Aspects 3 to 7.

[0043] (Aspect 9) A stator core including a plurality of electromagnetic steel sheets laminated in the axial direction, the plurality of electromagnetic steel sheets including at least one first electromagnetic steel sheet laminated from one end in the axial direction and at least one second electromagnetic steel sheet laminated from the at least one first electromagnetic steel sheet, the at least one first electromagnetic steel sheet being configured such that the axial compressive force by a fixture for fixing the stator core does not act thereon, or such that the axial compressive force by the fixture is smaller than the compressive force acting on the at least one second electromagnetic steel sheet. The stator core.

[0044] (Aspect 10) The at least one second electromagnetic steel sheet has a non-overlapping region that does not overlap with the at least one first electromagnetic steel sheet in the axial direction, the at least one second electromagnetic steel sheet has an adjacent electromagnetic steel sheet adjacent to the at least one first electromagnetic steel sheet, and the non-overlapping region of the adjacent electromagnetic steel sheet is configured to contact the fixture. The stator core according to Aspect 9.

[0045] (Aspect 11) A rotating electrical machine comprising a stator core having a plurality of electromagnetic steel sheets laminated in the axial direction, and a fixture for fixing the stator core, wherein the plurality of electromagnetic steel sheets include at least one first electromagnetic steel sheet laminated from one end in the axial direction, and at least one second electromagnetic steel sheet laminated from the at least one first electromagnetic steel sheet, the at least one second electromagnetic steel sheet has a non-overlapping region that does not overlap the at least one first electromagnetic steel sheet in the axial direction, the at least one second electromagnetic steel sheet has an adjacent electromagnetic steel sheet adjacent to the at least one first electromagnetic steel sheet, and the fixture is in contact with the non-overlapping region of the adjacent electromagnetic steel sheet.

[0046] (Aspect 12) In the non-overlapping region of the at least one second electromagnetic steel sheet, a bolt hole penetrating in the axial direction is arranged, a bolt of the fixture is inserted into the bolt hole, and a seating surface of the head of the bolt inserted into the bolt hole is in contact with the non-overlapping region of the adjacent electromagnetic steel sheet. The rotating electrical machine according to Aspect 11.

[0047] (Aspect 13) Further comprising a coil having a coil end arranged in the stator core and protruding from one end in the axial direction of the stator core, and a refrigerant flow path having a discharge port for discharging refrigerant toward the coil end, wherein the head of the bolt is not arranged on a straight line connecting the discharge port of the refrigerant flow path and the coil end. The rotating electrical machine according to Aspect 12.

[0048] (Aspect 14) The thickness of the at least one first electromagnetic steel sheet is larger than the thickness of the head of the bolt inserted into the bolt hole. The rotating electrical machine according to Aspect 13.

[0049] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness.

Claims

1. A stator core comprising a plurality of electromagnetic steel sheets stacked in the axial direction, wherein the plurality of electromagnetic steel sheets include at least one first electromagnetic steel sheet stacked from one end in the axial direction, and at least one second electromagnetic steel sheet stacked from the at least one first electromagnetic steel sheet, wherein the at least one second electromagnetic steel sheet has a non-overlapping region that does not overlap with the at least one first electromagnetic steel sheet in the axial direction, and the at least one second electromagnetic steel sheet has an adjacent electromagnetic steel sheet adjacent to the at least one first electromagnetic steel sheet, wherein the non-overlapping region of the adjacent electromagnetic steel sheet is configured to be in contact with a fastener for fixing the stator core.

2. The stator core according to claim 1, wherein at least one of the first electrical steel sheets is configured so that the fastener does not come into contact with it.

3. The stator core according to claim 1, wherein a bolt hole penetrating in the axial direction is provided in the non-overlapping region of at least one second electrical steel sheet, the bolt hole is configured to allow a bolt of the fastener to be inserted through it, and the non-overlapping region of the adjacent electrical steel sheet is configured to be in contact with the seating surface of the head of the bolt inserted into the bolt hole.

4. The stator core according to claim 3, wherein at least one second electrical steel sheet has a second electrical steel sheet projection that protrudes radially outward, and at least a portion of the bolt holes is located on the second electrical steel sheet projection.

5. The stator core according to claim 4, wherein the entire bolt hole is located on the second electromagnetic steel sheet projection.

6. The stator core according to claim 4 or 5, wherein the at least one first electromagnetic steel sheet also has a first electromagnetic steel sheet projection that protrudes radially outward, the at least one first electromagnetic steel sheet has a through hole that penetrates in the axial direction and has a larger diameter than the bolt hole, at least a portion of the through hole is arranged in the first electromagnetic steel sheet projection, and the bolt hole is arranged in the through hole in the axial direction.

7. The stator core according to claim 3, wherein at least one first electrical steel sheet has a through hole that penetrates in the axial direction and is larger in diameter than the bolt hole, and the bolt hole is located within the through hole in the axial direction.

8. The stator core according to claim 3, wherein the thickness of at least one first electrical steel sheet is greater than the thickness of the head of the bolt inserted through the bolt hole.

9. A stator core comprising a plurality of electromagnetic steel sheets stacked in the axial direction, wherein the plurality of electromagnetic steel sheets include at least one first electromagnetic steel sheet stacked from one end in the axial direction, and at least one second electromagnetic steel sheet stacked from the at least one first electromagnetic steel sheet, wherein the at least one first electromagnetic steel sheet is configured such that no axial compressive force is acted on it by a fastener that fixes the stator core, or such that the axial compressive force by the fastener is less than the compressive force acting on the at least one second electromagnetic steel sheet.

10. The stator core according to claim 9, wherein the at least one second electrical steel sheet has a non-overlapping region that does not overlap with the at least one first electrical steel sheet in the axial direction, the at least one second electrical steel sheet has an adjacent electrical steel sheet adjacent to the at least one first electrical steel sheet, and the non-overlapping region of the adjacent electrical steel sheet is configured to be in contact with the fastener.

11. A rotating electric machine comprising: a stator core having a plurality of electromagnetic steel sheets stacked in the axial direction; and a fixing device for fixing the stator core, wherein the plurality of electromagnetic steel sheets include: at least one first electromagnetic steel sheet stacked from one end in the axial direction; and at least one second electromagnetic steel sheet stacked from the at least one first electromagnetic steel sheet, wherein the at least one second electromagnetic steel sheet has a non-overlapping region that does not overlap with the at least one first electromagnetic steel sheet in the axial direction; the at least one second electromagnetic steel sheet has an adjacent electromagnetic steel sheet adjacent to the at least one first electromagnetic steel sheet; and the fixing device is in contact with the non-overlapping region of the adjacent electromagnetic steel sheet.

12. The rotating electric machine according to claim 11, wherein a bolt hole penetrating in the axial direction is provided in the non-overlapping region of at least one second electrical steel sheet, a bolt of the fixing device is inserted through the bolt hole, and the seating surface of the head of the bolt inserted through the bolt hole is in contact with the non-overlapping region of the adjacent electrical steel sheet.

13. The rotating electric machine according to claim 12, further comprising: a coil disposed on the stator core and having a coil end protruding from one end of the stator core in the axial direction; and a refrigerant flow path having a discharge port for discharging refrigerant toward the coil end, wherein the head of the bolt is not positioned on a straight line connecting the discharge port of the refrigerant flow path and the coil end.

14. The rotating electric machine according to claim 13, wherein the thickness of at least one first electromagnetic steel sheet is greater than the thickness of the head of the bolt inserted through the bolt hole.

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