Method for manufacturing stator core

Abstract

One embodiment of the present invention is a method for manufacturing a stator core, the method comprising: a punching step for punching a metal plate to form a strip-shaped core piece extending in a first direction; and a lamination step for forming a laminated body by bending and spirally laminating the band-shaped iron core pieces, with a direction perpendicular to the first direction being a second direction and one side of the band-shaped iron core pieces in the second direction being an inner diameter side. The band-shaped iron core sheet comprises: an iron core back sheet which extends in a first direction and is provided with a plurality of slits arranged in the first direction at one end of the iron core back sheet in a second direction; and a plurality of tooth pieces extending in the second direction between the slits from one end or the other end of the core back piece in the second direction. In each section between adjacent slits of the core back sheet, a first arc portion is provided at an end edge on the other side in the second direction, and a second arc portion is provided at an end edge on one side in the second direction. The first arcuate portion and the second arcuate portion extend in a concentric arcuate shape centered on an arcuate center located on one side in the second direction with respect to the core back sheet.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a stator core.

[0002] This application claims priority based on Japanese Patent Application No. 2022-105874 filed in Japan on June 30, 2022, the contents of which are cited here. Background Art

[0003] With the recent popularization of electric vehicles, the development of cheaper rotating electrical machines is underway. As one of such measures, a stator core has been proposed in which the material yield is increased by helically stacking strip-shaped plates (Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-359246 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Rotating electric machines require high output, and magnetic designs that take this into consideration are required. Therefore, for stator cores, it is not only required to improve the material yield, but also to form a shape that satisfies magnetic properties that can achieve high output. However, when strip-shaped plates are stacked in a spiral shape, the shape of the manufactured stator core is difficult to stabilize, and there is a problem that it is difficult to achieve high output.

[0009] In view of the above circumstances, one object of the present invention is to provide a method for manufacturing a stator core that can achieve high output while improving material yield.

[0010] Means for solving problems

[0011] One embodiment of the present invention is a method for manufacturing a stator core, the method comprising the following steps: a punching step of punching a metal plate to form a strip-shaped core sheet extending in a first direction; and a stacking step of setting a direction perpendicular to the first direction as a second direction, setting one side of the strip-shaped core sheet in the second direction as an inner diameter side, bending the strip-shaped core sheet and stacking the strip-shaped core sheet in a spiral shape to form a stacked body. The strip-shaped core sheet comprises: a core back sheet extending in the first direction, and having a plurality of slits arranged in the first direction at an end on one side of the second direction; and a plurality of tooth sheets extending in the second direction from an end on one side or the other side of the core back sheet between the slits. In each section between adjacent slits of the core back sheet, a first arc portion is provided at the end edge on the other side of the second direction, and a second arc portion is provided at the end edge on one side of the second direction. The first arc portion and the second arc portion extend in a concentric arc shape with an arc center located on one side of the core back piece in the second direction as the center.

[0012] Effects of the Invention

[0013] According to one aspect of the present invention, it is possible to provide a method for manufacturing a stator core that can improve material yield and achieve high output. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional schematic diagram of a rotating electric machine according to an embodiment.

[0015] Figure 2 This is a plan view showing a part of a stator core according to one embodiment.

[0016] Figure 3 This is a schematic diagram showing a laminated body according to one embodiment.

[0017] Figure 4 This is a flow chart of a method for manufacturing a stator according to an embodiment.

[0018] Figure 5 It is a schematic diagram which shows the punching process of one embodiment.

[0019] Figure 6 yes Figure 5 A partial enlarged view of . DETAILED DESCRIPTION

[0020] Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the drawings.

[0021] The center axis J is appropriately shown in each figure. The center axis J is an imaginary line passing through the center of the rotating electrical machine in the following embodiments. The Z axis appropriately shown in each figure indicates the direction in which the center axis J extends. In the following description, the axial direction of the center axis J, that is, the direction parallel to the Z axis, is referred to as the "axial direction", the radial direction centered on the center axis J is referred to as the "radial direction", and the circumferential direction centered on the center axis J is referred to as the "circumferential direction".

[0022] (Rotating Electric Machine)

[0023] Figure 1 1 is a schematic cross-sectional view of the rotary electric machine 10 along the central axis J.

[0024] The rotating electric machine 10 of the present embodiment is an inner rotor type rotating electric machine. In the present embodiment, the rotating electric machine 10 is a three-phase AC motor. The rotating electric machine 10 has both the function of a drive device and the function of a generator. The rotating electric machine 10 is driven by the supplied AC current to rotate the shaft 31, for example, to drive a vehicle. In addition, the rotating electric machine 10 regenerates the rotation of the shaft 31 to generate AC current.

[0025] The rotary electric machine 10 includes a rotor 30, a stator 40, and a housing 9. The housing 9 accommodates the rotor 30 and the stator 40 therein. The housing 9 rotatably supports a shaft 31 of the rotor 30 via a bearing.

[0026] (Rotor)

[0027] The rotor 30 is rotatable about a central axis J extending in the axial direction. The rotor 30 includes a shaft 31 , a rotor core 32 , and a plurality of magnets 36 .

[0028] The shaft 31 is cylindrical and extends axially with the central axis J as the center. The shaft 31 can rotate with the central axis J as the center. The rotor core 32 is fixed to the outer peripheral surface of the shaft 31. The rotor core 32 is provided with a plurality of magnet holding holes 38 extending along the axial direction. The plurality of magnet holding holes 38 are arranged along the circumferential direction. The magnets 36 are inserted into the magnet holding holes 38 and fixed to the rotor core 32. The plurality of magnets 36 are arranged along the circumferential direction. The magnetic poles of the magnets 36 adjacent to each other in the circumferential direction facing the radial outside are reversed with each other.

[0029] (stator)

[0030] The stator core 7 is located radially outside the rotor 30. The stator core 7 surrounds the rotor 30. The stator 40 is arranged radially outside the rotor 30. The stator 40 has the stator core 7 and a plurality of coils 42. The plurality of coils 42 are mounted on the stator core 7 via insulating paper (not shown). The coil 42 is, for example, a segment coil formed by connecting flat wires.

[0031] Figure 2It is a plan view showing a part of the stator core 7 .

[0032] The stator core 7 has an annular shape surrounding the central axis J of the rotary electric machine 10. The stator core 7 includes an annular core back member 7c and a plurality of teeth 7t extending radially from the core back member 7c and arranged in the circumferential direction.

[0033] Figure 3 Schematic diagram showing a laminated body 7A constituting the stator core 7 of the present embodiment.

[0034] like Figure 3 As shown, the stator core 7 of this embodiment is composed of a strip-shaped iron core sheet 60 stacked in a spiral shape. In this embodiment, the strip-shaped iron core sheet 60 is an electromagnetic steel sheet. The strip-shaped iron core sheet 60 has a core back sheet 61 extending in the circumferential direction and a plurality of tooth sheets 65 extending radially from the core back sheet 61 in a spirally stacked state.

[0035] Hereinafter, the features of the method for manufacturing the stator core 7 will be described together with the features of the stator core 7 .

[0036] Figure 4 This is a flowchart of the method for manufacturing the stator 40 according to the present embodiment.

[0037] The manufacturing method of the stator 40 of the present embodiment includes a stator core manufacturing step S10 for manufacturing the stator core 7 and a winding step S20 for mounting the coil 42 on the stator core 7. When the coil 42 is a segment coil, the winding step S20 is a step of inserting a plurality of coil wires 42a into the slots S of the stator core 7 from one axial side and connecting them on the other side.

[0038] The stator core manufacturing process S10 includes a punching process S11, a stacking process S12, and a fixing process S13. The punching process S11 is a process of punching the metal plate 6 to form the strip-shaped core sheet 60. The stacking process S12 is a process of stacking the strip-shaped core sheet 60 in a spiral shape to form a stacked body 7A. The fixing process S13 is a process of fixing the strip-shaped core sheet 60 of the stacked body 7A along the stacking direction.

[0039] Figure 5 It is a schematic diagram which shows the punching process S11.

[0040] The strip-shaped core piece 60 formed in the punching step S11 extends in one direction. Here, the direction in which the strip-shaped core piece 60 formed in the punching step S11 extends is referred to as a first direction D1. Also, a direction perpendicular to the first direction D1 is referred to as a second direction D2.

[0041] The metal plate 6 is, for example, a rolled plate. The metal plate 6 has an easy magnetization direction that is easily magnetized. The easy magnetization direction of the metal plate 6 is consistent with the rolling direction. The easy magnetization direction of the metal plate 6 is consistent with the second direction D2, for example. In this case, the direction in which the tooth piece 65 described later extends can be made consistent with the easy magnetization direction, and the magnetic properties of the stator core 7 can be improved.

[0042] As the metal plate 6, a known non-oriented electromagnetic steel sheet can be used. In addition, as the metal plate 6, a directional electromagnetic steel sheet can be used instead of a non-oriented electromagnetic steel sheet. The directionality of the magnetization ease of the directional electromagnetic steel sheet is large, and the directionality of the magnetization ease of the non-oriented steel sheet is below the threshold. In addition, the metal plate 6 can also be an amorphous metal or the like instead of an electromagnetic steel sheet.

[0043] The strip-shaped iron core pieces 60 of the present embodiment are punched out from the metal plate 6 in groups of two. That is, the punching step S11 is a step of punching out a pair of strip-shaped iron core pieces 60 extending in the same direction (first direction D1) and arranged in the second direction D2 from one metal plate 6. Here, in the punching step S11, one of the two strip-shaped iron core pieces 60 in a group is referred to as the first strip-shaped iron core piece 60A, and the other is referred to as the second strip-shaped iron core piece 60B. In the following description, when the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B are not distinguished from each other, they are simply referred to as the strip-shaped iron core piece 60.

[0044] The strip-shaped core sheet 60 includes a core back sheet 61 extending in a first direction D1 and a plurality of tooth sheets 65 extending in a second direction D2 from the core back sheet 61. The core back sheet 61 is stacked in a stacking direction in a stacking step S12 to form a core back member 7c. In addition, the tooth sheets 65 are stacked in a stacking step S12 to form a tooth portion 7t.

[0045] The tooth pieces 65 of the first strip-shaped core piece 60A and the second strip-shaped core piece 60B extend in opposite directions relative to the metal plate 6. That is, in the punching step S11, the tooth pieces 65 of the pair of strip-shaped core pieces 60A and 60B punched out from the metal plate 6 are on opposite sides relative to the directions in which the core back pieces 61 extend. In addition, the tooth pieces 65 of the first strip-shaped core piece 60A and the tooth pieces 65 of the second strip-shaped core piece 60B protrude in opposite directions relative to the strip-shaped core piece 60.

[0046] The tooth pieces 65 of the first strip-shaped iron core piece 60A are arranged between the tooth pieces 65 of the second strip-shaped iron core piece 60B arranged along the first direction D1. Similarly, the tooth pieces 65 of the second strip-shaped iron core piece 60B are arranged between the tooth pieces 65 of the first strip-shaped iron core piece 60A arranged along the first direction D1. That is, a pair of strip-shaped iron core pieces 60A and 60B are punched out in a manner that the tooth pieces 65 are alternately arranged in the first direction D1. According to this embodiment, in the metal plate 6, the gaps between the tooth pieces 65 can be effectively utilized, and the material yield rate when punching out the strip-shaped iron core pieces 60 from the metal plate 6 can be improved.

[0047] In the punching process S11, a gap G is provided throughout the entire area between the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B. In the punching process S11, the portion of the metal plate 6 corresponding to the gap G becomes an end material. The end material is discarded or recycled. According to the present embodiment, in the punching process, the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B do not share a fracture surface. According to the present embodiment, as a mold for performing the punching process, in order to form the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B, an optimal structure can be adopted respectively. As a result, according to the punching process of the present embodiment, the outer shapes of the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B can be punched out with high precision, respectively.

[0048] The core-back sheet 61 is provided with a plurality of slits 61s. The plurality of slits 61s are arranged in the first direction D1. The slits 61s are provided at an end portion of the core-back sheet 61 on one side in the second direction D2, and extend along the second direction D2.

[0049] Here, the end portion of the core back sheet 61 on one side in the second direction D2 refers to the direction that becomes the inner diameter side when the core back sheet 61 is deformed into a spiral shape in the stacking step S12. Figure 3 ), the strip iron core sheet 60 is bent with one side in the second direction D2 as the inner diameter side. Since the slit 61s is provided on the inner diameter side of the core back sheet 61, the core back sheet 61 is easily plastically deformed in the direction of closing the slit 61s, and the deformation amount and deformation position of the strip iron core sheet 60 in the lamination step S12 can be stably controlled.

[0050] In addition, in the present embodiment, the first strip-shaped core sheet 60A and the second strip-shaped core sheet 60B extend in the direction in which the tooth sheet 65 and the core back sheet 61 are opposed to each other. Figure 5 In the embodiment, the inner diameter side (one side in the second direction D2) of the first strip-shaped core sheet 60A and the inner diameter side (one side in the second direction D2) of the core back sheet 61 of the second strip-shaped core sheet 60B are in opposite directions.

[0051] The rotating electric machine 10 of the present embodiment is an inner rotor type, and the tooth portion 7t extends radially inward relative to the core back member 7c. Therefore, in the strip-shaped core sheet 60 of the present embodiment, the tooth piece 65 is arranged on the inner diameter side (one side of the second direction D2) of the core back sheet 61. In addition, in the strip-shaped core sheet 60 of the present embodiment, the tooth piece 65 and the slit 61s are arranged at the end of the same side of the core back sheet 61.

[0052] However, when the rotating electrical machine 10 is an outer rotor type, the tooth piece 65 is arranged on the outer shape side (the other side in the second direction D2) of the core back piece 61. In this case, the tooth piece 65 and the slit 61s are arranged on the opposite end of the core back piece 61.

[0053] In this way, regardless of whether it is an inner rotor type or an outer rotor type, the slit 61s is always arranged on one side in the second direction (i.e., the inner diameter side). On the other hand, the tooth piece 65 is arranged in which direction in the second direction (outer diameter side or inner diameter side) according to whether it is an inner rotor type or an outer rotor type. That is, the slit 61s is provided at the end of one side in the second direction D2 of the core back sheet 61, and the tooth piece 65 extends along the second direction D2 from the end of one side or the other side in the second direction D2 of the core back sheet 61.

[0054] The slit 61s extends from one side of the second direction D2 of the entire width of the core back sheet 61 along the second direction D2 to the approximate center of the second direction D2. The slit 61s of this embodiment is widest at the opening end, and the width gradually narrows as it moves from the opening end toward the inner side. In addition, in the following description, the front end of the slit 61s is referred to as the slit end 61p. The slit end 61p is the end of the slit 61s in the second direction D2 that is farthest from the opening end.

[0055] The plurality of slits 61 s are arranged in the first direction D1 . The strip-shaped core sheet 60 is provided with a plurality of partitions A partitioned by the slits 61 s . That is, the partitions A are provided between adjacent slits 61 s of the core back sheet 61 .

[0056] The plurality of sections A are arranged along the first direction D1. The sections A adjacent to each other in the first direction D1 are divided by the slit 61s and a boundary line B extending from a slit end 61p of the slit 61s to the other side of the core back sheet 61 in the second direction D2.

[0057] In the present embodiment, the first arc portion 61a and the boundary recess 61c are provided at the end edge on the other side of the second direction D2 of the core back sheet 61. In the stator core 7 formed by spirally stacking the strip-shaped core sheets 60, the end edge on one side of the second direction D2 of the core back sheet 61 constitutes the outer peripheral surface. Therefore, the first arc portion 61a and the boundary recess 61c are arranged on the outer diameter side of the core back sheet 61.

[0058] The first arc portion 61a is provided in each section A. That is, the first arc portion 61a is provided at the end edge on the other side in the second direction D2 in each section A of the core back piece 61. The first arc portion 61a extends in an arc shape with the arc center C as the center.

[0059] In this specification, the "arc center" refers to the center of the curvature radius of the arc. Therefore, the arc center is at a constant distance from each part of the arc shape centered on the arc center.

[0060] In the present embodiment, one arc center C is provided in each partition A. Therefore, in the partitions A adjacent to each other in the first direction D1, the first arc portion 61a extends in an arc shape with different arc centers C as the center. The arc center C is located on one side (inner diameter side) in the second direction relative to the core back sheet 61. Therefore, the first arc portion 61a protrudes outward in the width direction of the core back sheet 61.

[0061] In this specification, a direction perpendicular to the direction in which the core-back piece 61 extends may be referred to as a width direction of the core-back piece 61. The width direction of the core-back piece 61 is a direction parallel to the second direction D2.

[0062] In the present embodiment, one first arc portion 61a is provided in each subarea A. However, a plurality of first arc portions 61a may be provided in one subarea A. In this case, the plurality of first arc portions 61a arranged in the same subarea A share one arc center C. In addition, the curvature radii of the plurality of first arc portions 61a arranged in the same subarea A are equal to each other. That is, all the first arc portions 61a in each subarea A are arranged on the same arc.

[0063] The boundary recess 61c is recessed toward the inner side in the width direction of the core back sheet 61. The boundary recess 61c is arranged on the boundary line B between the adjacent partitions A. The boundary recess 61c is arranged on the extension line of the slit 61s. In the stacking step S12, the core back sheet 61 is formed into a spiral shape as a whole by plastic deformation in the area between the slit end 61p and the boundary recess 61c.

[0064] In the present embodiment, the second arc portion 61b is provided at the end edge on one side in the second direction D2 in each section A of the core back sheet 61. In the stator core 7 formed by spirally stacking the strip-shaped core sheets 60, the end edge on the other side in the second direction D2 of the core back sheet 61 constitutes the inner peripheral surface. Therefore, the second arc portion 61b is arranged on the inner diameter side of the core back sheet 61.

[0065] The second arc portion 61 b ​​extends in an arc shape around the same arc center C as the first arc portion 61 a of the section A. The second arc portion 61 b ​​is recessed inward in the width direction of the core back piece 61 .

[0066] Two second arc portions 61b are provided in each partition A. The two second arc portions 61b provided in each partition A are arranged on both sides of the tooth piece 65 in the first direction. The two second arc portions 61b extend from the base end portion 65g of the tooth piece 65 to both sides in the first direction in each partition A. The two second arc portions 61b of each partition A share the arc center C, and the curvature radii are equal to each other. That is, the two second arc portions 61b of each partition A are arranged on the same arc.

[0067] The first arc portion 61a and the second arc portion 61b of the present embodiment extend in a concentric arc shape with the arc center C as the center. That is, the first arc portion 61a and the second arc portion 61b share the arc center C. In addition, the arc center C is located on one side (inner diameter side) of the second direction D2 relative to the core back sheet 61, and the first arc portion 61a is larger than the second arc portion 61b in terms of the distance from the arc center C. Therefore, the curvature radius of the first arc portion 61a is larger than the curvature radius of the second arc portion 61b.

[0068] In the punching step S11, the arc center C is set for each partition A. In the stacking step S12, the strip core piece 60 is deformed into a spiral shape so that the arc center C set for each partition A coincides with the center axis J. In the strip core piece 60 of the present embodiment, a slit 61s is provided on the core back sheet 61. The strip core piece 60 plastically deforms the open end of the slit 61s in the closing direction. A plurality of notches 7k (see FIG. 1 ) arranged in the circumferential direction as traces of the slit 61s are provided on the inner circumferential surface 7cb of the core back member 7c stacked in a spiral shape. Figure 2 ). Each notch 7k is arranged between the teeth 7t adjacent to each other in the circumferential direction.

[0069] According to the strip-shaped core sheet 60 of the present embodiment, the area that is plastically deformed in the lamination step S12 can be limited to the area radially outside the seam end 61p. In other words, according to the strip-shaped core sheet 60 of the present embodiment, the area that is plastically deformed in the lamination step S12 can be prevented from spreading to areas other than the area radially outside the seam end 61p. That is, in the lamination step S12, the deformation in the partition A divided by the seam 61s can be prevented from spreading to the inner and outer edges of the core back sheet 61, and by making the inner and outer edges arc-shaped in advance, the core back component 7c that maintains its shape can be formed.

[0070] The first arc portion 61a and the second arc portion 61b are provided at the end edges on one side and the other side in the second direction D2 of the core back sheet 61 of the present embodiment, respectively. Figure 2As shown, the shapes of the first arc portion 61a and the second arc portion 61b are also maintained in the core back member 7c formed through the lamination step S12. According to the present embodiment, in the outer peripheral surface 7ca of the core back member 7c, a plurality of first arc portions 61a arranged along the circumferential direction can be arranged on a circle centered on the central axis J. Similarly, in the inner peripheral surface 7cb of the core back member 7c, a plurality of second arc portions 61b arranged along the circumferential direction can be arranged on a circle centered on the central axis J. That is, the outer peripheral surface 7ca of the core back member 7c and the inner peripheral surface 7cb of the core back member 7c are arranged on concentric circles sharing the same center (arc center C).

[0071] According to the present embodiment, the stator core 7 can be manufactured with the inner diameter and the outer diameter being stable in the circumferential direction. Therefore, the radial width of the core back member 7c can be made constant in the circumferential direction, and the magnetic properties of the core back member 7c can be improved. That is, according to the present embodiment, by stacking the strip-shaped core pieces 60 in a spiral shape, the material yield can be improved, and the stator core 7 capable of achieving high output can be manufactured.

[0072] In addition, according to the present embodiment, the outer peripheral surface of the stator core 7 can be made close to a perfect circle, and the stator core 7 can be fixed to the housing 9 (see FIG. Figure 1 ), the fixing strength of the stator core 7 relative to the housing 9 can be improved.

[0073] like Figure 5 As shown in FIG. 1 , the tooth piece 65 extends from the core back piece 61 in the second direction D2 between the slits 61s. One tooth piece 65 of the present embodiment is provided in each section A, respectively.

[0074] In each section A, a third arc portion 65c is provided at the front end edge of the tooth piece 65. Here, the front end edge of the tooth piece 65 refers to the edge of the front end portion of the tooth piece 65 in the direction in which the tooth piece 65 extends from the core back piece 61 (ie, the second direction D2).

[0075] The third arc portion 65c extends in an arc shape with the same arc center C as the first arc portion 61a of the partition A as the center. Therefore, the third arc portion 65c shares the arc center C with the first arc portion 61a and the second arc portion 61b. The second arc portion 61b of the present embodiment extends in a concave shape. The curvature radius of the third arc portion 65c is smaller than the curvature radius of the first arc portion 61a and the second arc portion 61b.

[0076] like Figure 2As shown, in the tooth portion 7t of the stator core 7 of the present embodiment, the third arc portion 65c faces the central axis J side. The front end edge of the tooth portion 7t of the present embodiment is arranged on a concentric circle that shares the same center (arc center C) as the outer peripheral surface 7ca of the core back member 7c and the inner peripheral surface 7cb of the core back member 7c. That is, according to the present embodiment, the front end of the tooth portion 7t can be formed into an arc shape centered on the central axis J. As a result, the distance between the front end of the tooth portion 7t and the rotor 30 can be made constant in the circumferential direction, and the magnetic flux can flow smoothly between the tooth portion 7t and the rotor 30.

[0077] like Figure 5 As shown in FIG. 1 , the third arc portion 65c of the present embodiment is in an arc shape concentric with the first arc portion 61a and the second arc portion 61b, so that in the punching step S11, it is easy to improve the accuracy of the outer shapes of the first arc portion 61a, the second arc portion 61b, and the third arc portion 65c. Thus, the performance of the stator core 7 can be improved, and the high output of the rotating electrical machine 10 can be achieved.

[0078] Figure 6 yes Figure 5 A partial enlarged view of .

[0079] like Figure 6 As shown in FIG. 1 , in the punching step S11, the second arc portion 61b of the first strip-shaped iron core piece 60A and the third arc portion 65c of the second strip-shaped iron core piece 60B are opposed in the second direction D2. In addition, as described above, a gap G is provided over the entire region between the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B. Therefore, a gap is provided between the second arc portion 61b and the third arc portion 65c of the pair of strip-shaped iron core pieces 60A and 60B that are opposed to each other.

[0080] Here, the portion between the second arc portion 61b and the third arc portion 65c in the gap G between the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B is referred to as the first gap G1. That is, in the punching step S11, the second arc portion 61b of one of the pair of strip-shaped iron core pieces 60 and the third arc portion 65c of the other of the pair of strip-shaped iron core pieces 60 are punched out from the metal plate 6 in a state of being opposed to each other with the first gap G1 therebetween.

[0081] According to the present embodiment, a first gap G1 is provided between the end edge of the core back sheet 61 of one of the pair of strip-shaped core sheets 60 (e.g., the first strip-shaped core sheet 60A) and the front end of the tooth sheet 65 of the other of the pair of strip-shaped core sheets 60 (e.g., the second strip-shaped core sheet 60B). Therefore, the punching accuracy of the outer shapes of the core back sheet 61 and the tooth sheet 65 can be improved, and the performance of the stator core 7 can be further improved.

[0082] In the present embodiment, the second arc portion 61b and the third arc portion 65c facing each other in the metal plate 6 are curved in an arc shape. Therefore, the first gap G1 between the second arc portion 61b and the third arc portion 65c becomes wider toward the outer side in the width direction of the tooth piece 65. Therefore, when the umbrella-shaped portion 65d is provided on both sides in the width direction of the tooth piece 65, it is easy to improve the outer shape accuracy of the umbrella-shaped portion 65d.

[0083] In addition, in this specification, the direction perpendicular to the direction in which the tooth piece 65 extends may be referred to as the width direction of the tooth piece 65. The width direction of the tooth piece 65 is a direction parallel to the first direction D1.

[0084] like Figure 5 As shown, in the tooth piece 65, the end portion connected to the core back piece 61 is set as the base end portion 65g, and the end portion farthest from the core back piece 61 is set as the front end portion 65h. The base end portion 65g is the end portion on the outer diameter side (the other side of the second direction D2) of the tooth piece 65, and the front end portion 65h is the end portion on the inner diameter side (the one side of the second direction D2) of the tooth piece 65.

[0085] The tooth piece 65 is provided with a pair of umbrella-shaped portions 65d located at the front end portion 65h, a pair of recessed portions 65b located at the base end portion 65g, and a pair of side ends 65e connecting the front end portion 65h and the base end portion 65g. The pair of umbrella-shaped portions 65d protrude outward in the width direction of the tooth piece 65. The pair of recessed portions 65b are recessed inward in the width direction of the tooth piece 65.

[0086] The side end portions 65e are located on both sides of the tooth piece 65 in the width direction. The side end portions 65e connect the umbrella-shaped portion 65d and the recessed portion 65b in a straight line. The pair of side end portions 65e of one tooth piece 65 approaches each other as it moves from the base end portion 65g of the tooth piece 65 toward the front end portion 65h. That is, the tooth piece 65 becomes thinner between the recessed portion 65b and the umbrella-shaped portion 65d toward the front end portion 65h. In one strip-shaped core sheet 60, the opposite side end portions 65e of two adjacent tooth pieces 65 in the first direction D1 separate from each other as they move away from the core back sheet 61 along the second direction D2.

[0087] In this embodiment, the angle α formed by the pair of side ends 65e of the tooth piece 65 is consistent with the angle obtained by dividing 360° by the number of slots of the stator core 7. That is, when the number of slots of the stator core 7 is N, the angle α formed by the pair of side ends 65e can be expressed by 360° / N.

[0088] The strip-shaped core piece 60 is deformed into a spiral shape in the lamination step S12 described later. In the lamination step S12, the strip-shaped core piece 60 is plastically deformed by 360° / N on the boundary line B between the partitions A. As a result, the tooth pieces 65 adjacent to each other in the first direction D1 in the strip-shaped core piece 60 make the front end portions 65h approach each other. Figure 2 In the stator core 7 shown, the opposing side ends 65e of the teeth 7t adjacent in the circumferential direction are parallel to each other. That is, the teeth 7t of the stator core 7 has a pair of side ends 65e facing one side and the other side in the circumferential direction, and the side ends 65e adjacent in the circumferential direction extend parallel to each other.

[0089] According to the present embodiment, the slots S between the teeth 7t extend in the radial direction with a certain width. Therefore, the coil wires 42a can be densely arranged in the slots S, and the space factor of the coil wires 42a in the slots can be increased, thereby increasing the output of the rotating electrical machine 10. Such an effect is particularly significant when the coil 42 is a segmented coil and a flat wire is used as the coil wire 42a.

[0090] Here, the so-called "parallel" does not need to be strictly parallel in mathematical sense, but it can be parallel to the extent that the above-mentioned effect can be fully obtained. More specifically, the angle between the side ends 65e can be within the range of 0°±10°. Similarly, in the tooth piece 65, the angle α formed by the pair of side ends 65e can be within the range of ±10° relative to 360° / N.

[0091] like Figure 6 As shown, in the punching process S11, the umbrella-shaped portion 65d of the first strip-shaped iron core piece 60A is arranged inside the recessed portion 65b of the second strip-shaped iron core piece 60B. Similarly, the umbrella-shaped portion 65d of the second strip-shaped iron core piece 60B is arranged inside the recessed portion 65b of the first strip-shaped iron core piece 60A. In addition, as described above, a gap G is provided over the entire area between the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B. Therefore, a gap is provided between the umbrella-shaped portion 65d and the recessed portion 65b of a pair of strip-shaped iron core pieces 60A and 60B.

[0092] Generally, it is known that various effects such as torque fluctuations when the rotating electric machine 10 is driven can be obtained by providing the umbrella-shaped portion 65d on the teeth 7t of the stator core 7. However, when the tooth pieces 65 are alternately arranged to punch out the first strip-shaped core piece 60A and the second strip-shaped core piece 60B as shown in the present embodiment, if the umbrella-shaped portion 65d is provided on the tooth piece 65, the first strip-shaped core piece 60A and the second strip-shaped core piece 60B cannot be sufficiently close to each other. Therefore, the end material formed between the first strip-shaped core piece 60A and the second strip-shaped core piece 60B becomes larger, and as a result, there is a problem of deterioration in material yield.

[0093] According to the present embodiment, a recess 65b is provided at the base end 65g of the tooth piece 65, and an umbrella-shaped portion 65d is arranged inside the recess 65b. Therefore, the umbrella-shaped portion 65d can be provided on the tooth piece 65, and the tooth piece 65 of the first strip-shaped iron core piece 60A and the tooth piece 65 of the second strip-shaped iron core piece 60B can be arranged close to each other. Thus, the material yield rate in the punching process S11 of the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B can be improved.

[0094] Here, the portion between the umbrella-shaped portion 65d and the recessed portion 65b in the gap G between the first strip-shaped iron core piece 60A and the second strip-shaped iron core piece 60B is referred to as the second gap G2. That is, in the punching step S11, the outer edge of the umbrella-shaped portion 65d of one of the pair of strip-shaped iron core pieces 60 and the inner edge of the recessed portion 65b of the other of the pair of strip-shaped iron core pieces 60 are punched out from the metal plate 6 in a state where they are opposed to each other with the second gap G2 interposed therebetween.

[0095] According to the present embodiment, a second gap G2 is provided between the outer edge of the umbrella-shaped portion 65d of one of the pair of strip-shaped iron core sheets 60 (e.g., the first strip-shaped iron core sheet 60A) and the inner edge of the recessed portion 65b of the other of the pair of strip-shaped iron core sheets 60 (e.g., the second strip-shaped iron core sheet 60B). Therefore, the punching accuracy of the outer shape of the umbrella-shaped portion 65d can be improved, and the performance of the umbrella-shaped portion 65d can be further improved.

[0096] like Figure 2 As shown, the stacked body 7A formed in the stacking step S12 is composed of a strip-shaped iron core sheet 60 connected together. The strip-shaped iron core sheet 60 constituting the stacked body 7A has two ends in the length direction (i.e., the first direction D1). Here, in the strip-shaped iron core sheet 60, the end located on the side closest to the first direction D1 is set as the starting end 60p, and the end located on the other side closest to the first direction D1 is set as the terminal end 60q. In addition, in the strip-shaped iron core sheet 60, the tooth piece 65 located on the side closest to the first direction D1 is set as the starting tooth piece 65p, and the tooth piece 65 located on the other side closest to the first direction D1 is set as the terminal tooth piece 65q.

[0097] The strip-shaped core sheet 60 is spirally wound multiple times in the spiral winding direction T from the starting end portion 60p to the terminal portion 60q in the laminate 7A. The edge of the starting end portion 60p on the other side of the spiral winding direction T and the edge of the terminal portion 60q on one side of the spiral winding direction T are located on the core back sheet 61. One section A of the starting end portion 60p and one section A of the terminal portion 60q of the strip-shaped core sheet 60 overlap each other. One section A of the starting end portion 60p and one section A of the terminal portion 60q that overlap each other in the stacking direction are defined as an overlapping portion P. The starting end tooth piece 65p and the terminal tooth piece 65q are located in the overlapping portion P.

[0098] In the stacking step S12 of the present embodiment, the starting tooth piece 65p and the terminal tooth piece 65q overlap each other when viewed from the stacking direction. That is, in the stator core 7, the starting tooth piece 65p and the terminal tooth piece 65q of the spirally stacked strip core pieces 60 overlap each other when viewed from the stacking direction. In addition, the stacking direction here refers to the direction parallel to the central axis J of the stator core 7, which is Figure 2 The front direction of the paper.

[0099] According to the present embodiment, the start tooth piece 65p and the end tooth piece 65q constitute one tooth portion 7t. The start tooth piece 65p and the end tooth piece 65q are respectively located at one end and the other end of the stacking direction of one tooth portion 7t of the stator core 7.

[0100] According to the present embodiment, the dimensions of the plurality of teeth 7t of the stator core 7 in the stacking direction can be made uniform except for the teeth 7t in the overlapped portion P. As a result, the magnetic characteristics of the stator core 7 can be stabilized along the circumferential direction, and the high output of the rotating electric machine 10 can be achieved. In addition, the dimension of the stator core 7 in the stacking direction is larger at the overlapped portion P than at other portions by the thickness of one strip-shaped core sheet 60.

[0101] In the fixing process S13, a fixing portion 7a is formed to connect a plurality of strip-shaped core sheets 60 arranged in the stacking direction. In the present embodiment, a plurality of fixing portions 7a are provided on the outer peripheral surface 7ca of the stator core 7. The plurality of fixing portions 7a are arranged at equal intervals along the circumferential direction of the central axis J. In the present embodiment, the plurality of fixing portions 7a are arranged at intervals of 60° around the central axis J. In the present embodiment, one fixing portion 7a is arranged radially outside the portion where the starting tooth piece 65p and the terminal tooth piece 65q overlap. According to the present embodiment, the two ends of the strip-shaped core sheet 60 in the first direction D1 can be fixed to each other, and the shape of the stack 7A can be stabilized. In addition, the starting end portion 60p and the terminal end portion 60q of the strip-shaped core sheet 60 can be suppressed from floating at the end surface of the stacking direction of the stack 7A with a small number of fixing portions 7a.

[0102] The fixing portion 7a of this embodiment is a welded portion extending along the lamination direction on the outer peripheral surface 7ca of the stator core 7. The welded portion is formed by, for example, laser welding. Alternatively, the fixing portion 7a may be a caulking portion provided on the core back member 7c or the teeth 7t.

[0103] In the present embodiment, a groove 7g extending in the stacking direction is provided on the outer peripheral surface 7ca of the core back member 7c. The groove 7g can be formed by pre-arranging recesses arranged at equal intervals at the end of the outer diameter side of the strip-shaped core sheet 60 and overlapping the recesses in the stacking direction in the stacking process. In addition, the groove 7g can also be formed on the outer peripheral surface of the stack 7A by machining after the stacking process. The fixing portion 7a of the present embodiment is a welding portion arranged in the groove 7g. Therefore, it is possible to suppress the convex portion protruding radially outward relative to the outer peripheral surface 7ca of the core back member 7c from protruding radially outward in the welding process.

[0104] The embodiments of the present invention are described above, but each structure in each embodiment and their combination are examples, and addition, omission, replacement and other changes of the structure can be made without departing from the scope of the present invention. In addition, the present invention is not limited to the embodiments.

[0105] In the above embodiment, a case where one tooth piece 65 is provided in one section A is described. This makes it easy to improve the material yield when punching the metal plate 6 to form the band-shaped core piece 60. However, two or more tooth pieces 65 may be provided in one section A.

[0106] In the above-mentioned embodiment, the case where the stator core 7 is constituted by one laminated body 7A is described. However, the stator core 7 may be constituted by stacking a plurality of laminated bodies 7A in the stacking direction.

[0107] In the above-mentioned embodiment, the inner rotor type rotating electrical machine 10 is described, but the same structure can be adopted also in the outer rotor type rotating electrical machine 10 .

[0108] The shape of the slit 61s in the above embodiment is an example. The slit 61s only needs to be provided at the end of the core back sheet 61 on one side in the second direction D2, and may not extend in a direction parallel to the second direction D2 or may not extend linearly.

[0109] The rotating electric machine 10 is not limited to a motor, but may be a generator. The use of the rotating electric machine 10 is not particularly limited. The rotating electric machine 10 may be mounted on a vehicle for a purpose other than rotating an axle, for example, or may be mounted on a device other than a vehicle. The posture when using the rotating electric machine is not particularly limited.

[0110] In addition, the present technology can adopt the following structures.

[0111] (1) A method for manufacturing a stator core, the manufacturing method comprising the following steps: a punching step, in which a metal plate is punched to form a strip-shaped iron core sheet extending in a first direction; and a stacking step, in which a direction perpendicular to the first direction is set as a second direction, one side of the strip-shaped iron core sheet in the second direction is set as an inner diameter side, and the strip-shaped iron core sheet is bent and stacked in a spiral shape to form a stacked body, wherein the strip-shaped iron core sheet comprises: an iron core back sheet extending in the first direction, and having a plurality of strips arranged in the first direction at an end portion on one side of the second direction. a plurality of slits; and a plurality of tooth plates extending along the second direction from the end of the core back sheet on one side or the other side of the second direction between the slits, wherein in each partition between adjacent slits of the core back sheet, a first arc portion is provided at the end edge on the other side of the second direction, and a second arc portion is provided at the end edge on one side of the second direction, and the first arc portion and the second arc portion extend in a concentric arc shape with the center of the arc on the side of the core back sheet in the second direction as the center.

[0112] (2) A method for manufacturing a stator core according to (1), wherein, in each partition between adjacent slits of the core back sheet, a third arc portion extending in an arc shape centered on the arc center is provided at the front end edge of the tooth sheet.

[0113] (3) A method for manufacturing a stator core according to (2), wherein the punching process is a process as follows: a pair of the strip-shaped iron core sheets arranged along the second direction are punched out from one sheet of the metal plate, and the pair of the strip-shaped iron core sheets are punched out in the following manner: the tooth sheets are alternately arranged in the first direction in such a manner that the tooth sheets are on opposite sides of each other with respect to the directions in which the tooth sheets extend relative to the respective core back sheets, and in the punching process, the second arc portion of one of the pair of the strip-shaped iron core sheets and the third arc portion of the other of the pair of the strip-shaped iron core sheets are punched out from the metal plate in a state of being opposed to each other with a first gap therebetween, and the first gap widens toward the outside in the width direction of the tooth sheets.

[0114] (4) A method for manufacturing a stator core according to any one of (1) to (3), wherein the punching step is a step of punching out a pair of the strip-shaped iron core sheets arranged along the second direction from one sheet of the metal plate, the pair of the strip-shaped iron core sheets being punched out in the following manner: the tooth sheets are alternately arranged in the first direction in such a manner that the directions in which the tooth sheets extend relative to the respective core back sheets are on opposite sides of each other, the tooth sheets being provided with: a pair of umbrella-shaped portions, the pair of umbrella-shaped portions being located at the front end portions and protruding outward in the width direction of the tooth sheets; and a pair of recessed portions being located at the base end portions and recessed inward in the width direction of the tooth sheets, wherein in the punching step, an outer edge of the umbrella-shaped portion of one of the pair of the strip-shaped iron core sheets and an inner edge of the recessed portion of the other of the pair of the strip-shaped iron core sheets are punched out from the metal plate in a state where they are opposed to each other with a second gap therebetween.

[0115] (5) A method for manufacturing a stator core according to any one of (1) to (4), wherein, in the strip-shaped iron core sheet, the tooth piece located on one side closest to the first direction is set as the starting tooth piece, and the tooth piece located on the other side closest to the first direction is set as the terminal tooth piece, and in the stacking step, when viewed from the stacking direction, the starting tooth piece and the terminal tooth piece overlap with each other.

[0116] (6) A method for manufacturing a stator core according to (5), wherein the method for manufacturing a stator core further comprises a fixing step for fixing the strip-shaped iron core pieces of the stacked body along a stacking direction, wherein a fixing portion is formed to interconnect a plurality of strip-shaped iron core pieces arranged along the stacking direction, and the fixing portion is arranged radially outside a portion where the starting tooth piece and the terminal tooth piece overlap.

[0117] (7) A stator core, which is formed by spirally stacking strip-shaped iron core sheets, wherein the stator core has: a core back component which is annular; and a plurality of teeth, which extend radially from the core back component and are arranged circumferentially, and the outer circumferential surface of the core back component and the inner circumferential surface of the core back component are arranged on concentric circles sharing the same center.

[0118] (8) The stator core according to (7), wherein the front end edge of the tooth portion is arranged on a concentric circle that shares the same center with the outer peripheral surface of the core back member and the inner peripheral surface of the core back member.

[0119] (9) The stator core according to (7) or (8), wherein a plurality of notches arranged in a circumferential direction are provided on the inner peripheral surface of the core back member.

[0120] (10) A stator core according to any one of (7) to (9), wherein the strip iron core sheet has a core back sheet extending in the circumferential direction and a plurality of tooth sheets extending in the radial direction from the core back sheet, and in the strip iron core sheet, a tooth sheet located on one side in the length direction of the strip iron core sheet is set as a starting tooth sheet, and a tooth sheet located on the other side of the strip iron core sheet closest to the length direction is set as a terminal tooth sheet, and when viewed from the stacking direction, the starting tooth sheet and the terminal tooth sheet overlap with each other.

[0121] (11) The stator core according to (10), wherein the stator core has a fixing portion for connecting the strip-shaped core sheets arranged along the stacking direction to each other, and the fixing portion is arranged radially outside the portion where the starting tooth piece and the terminal tooth piece overlap.

[0122] (12) The stator core according to (11), wherein a groove extending in a lamination direction is provided on an outer peripheral surface of the core back member, and the fixing portion is a welded portion arranged in the groove.

[0123] (13) The stator core according to any one of (7) to (12), wherein the tooth portion has a pair of side ends facing one side and the other side in the circumferential direction, and the side ends adjacent to each other in the circumferential direction extend parallel to each other.

[0124] Description of symbols

[0125] 6: metal plate; 7: stator core; 7a: fixing portion; 7A: laminated body; 40: stator; 60: strip core piece; 61: core back piece; 61a: 1st arc portion; 61b: 2nd arc portion; 61s: seam; 65: tooth piece; 65b: recessed portion; 65c: 3rd arc portion; 65d: umbrella-shaped portion; 65g: base end portion; 65h: front end portion; 65p: starting tooth piece; 65q: terminal tooth piece; A: partition; C: arc center; D1: 1st direction; D2: 2nd direction; G: gap; G1: 1st gap; G2: 2nd gap; S11: punching process; S12: stacking process; S13: fixing process.

Claims

1. A method for manufacturing a stator core, the method comprising the following steps: a punching step of punching the metal plate to form a strip-shaped core sheet extending in a first direction; and a lamination step, wherein a direction perpendicular to the first direction is set as a second direction, one side of the strip-shaped iron core sheet in the second direction is set as an inner diameter side, and the strip-shaped iron core sheet is bent and spirally laminated to form a laminated body, The strip-shaped iron core sheet has: a core back sheet extending in the first direction and having a plurality of slits arranged in the first direction at an end portion on one side in the second direction; and a plurality of tooth pieces extending from an end portion of the core back piece on one side or the other side in the second direction between the slits along the second direction, In each section between the adjacent slits of the core back sheet, a first arc portion is provided at the end edge on the other side in the second direction, and a second arc portion is provided at the end edge on one side in the second direction. The first arc portion and the second arc portion extend in a concentric arc shape with an arc center located on one side of the core back piece in the second direction as the center.

2. The method for manufacturing a stator core according to claim 1, wherein: In each section between the adjacent slits of the core back piece, a third arc portion extending in an arc shape with the arc center as the center is provided at the front end edge of the tooth piece.

3. The method for manufacturing a stator core according to claim 2, wherein: The punching step is a step of punching out a pair of the strip-shaped core sheets arranged in the second direction from one sheet of the metal plate, The pair of strip-shaped core sheets are punched out in such a manner that the tooth pieces are alternately arranged in the first direction so that the directions in which the tooth pieces extend relative to the core back sheets are opposite to each other. In the punching step, the second arc portion of one of the pair of strip-shaped iron core sheets and the third arc portion of the other of the pair of strip-shaped iron core sheets are punched out from the metal plate in a state where they are opposed to each other with a first gap therebetween. The first gap widens toward the outer side in the width direction of the tooth piece.

4. The method for manufacturing a stator core according to claim 1, wherein: The punching step is a step of punching out a pair of the strip-shaped core sheets arranged in the second direction from one sheet of the metal plate, The pair of strip-shaped core sheets are punched out in such a manner that the tooth pieces are alternately arranged in the first direction so that the directions in which the tooth pieces extend relative to the core back sheets are opposite to each other. The tooth piece is provided with: a pair of umbrella-shaped portions, the pair of umbrella-shaped portions being located at the front end portion and protruding outward in the width direction of the tooth piece; and A pair of recessed portions, the pair of recessed portions being located at the base end portion and recessed inwardly in the width direction of the tooth piece, In the punching step, the outer edge of the umbrella-shaped portion of one of the pair of strip-shaped core sheets and the inner edge of the recessed portion of the other of the pair of strip-shaped core sheets are punched out from the metal plate in a state where they face each other with a second gap therebetween.

5. The method for manufacturing a stator core according to claim 1, wherein: In the strip-shaped core sheet, the tooth piece located closest to one side in the first direction is set as the starting tooth piece, and the tooth piece located closest to the other side in the first direction is set as the ending tooth piece. In the stacking step, the start-end tooth piece and the end-end tooth piece overlap each other when viewed from a stacking direction.

6. The method for manufacturing a stator core according to claim 5, wherein: The method for manufacturing the stator core further comprises a fixing step of fixing the strip-shaped core sheets of the stacked body along a stacking direction. In the fixing step, a fixing portion is formed to connect a plurality of strip-shaped core sheets arranged along a stacking direction to each other. The fixing portion is arranged radially outside a portion where the starting tooth piece and the terminal tooth piece overlap.

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