Laminated iron core manufacturing method and laminated iron core

Abstract

This method for manufacturing a laminated iron core has: a punching step in which a steel plate is punched to form a rear yoke-forming section extending in one direction and a plurality of teeth extending from the rear yoke-forming section in a direction intersecting the one direction when the steel plate is viewed in the thickness direction; and a bending step in which the rear yoke forming portion formed in the punching step is bent so as to have an arc shape when viewed in the thickness direction, thereby forming the rear yoke portion. In the punching step, a pair of protrusions protruding in one direction and in the other direction of the width of the teeth are formed at the tips of the plurality of teeth, and when the steel plate is viewed in the thickness direction, the number of protrusions in the plurality of teeth is larger than the number of protrusions in the width direction of the teeth, and the number of protrusions in the width direction of the teeth is smaller than the number of protrusions in the thickness direction. A recessed portion is formed in a portion where the size of a gap with the teeth located next to each of the teeth is smaller than the size of the pair of protrusions in the teeth in the width direction, and the recessed portion is recessed in the width direction and has a recessed region larger than the protrusions.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a laminated iron core and the laminated iron core. Background Art

[0002] There is known a method of punching out an electromagnetic steel sheet as a material of a laminated core to form a back yoke forming portion extending in a straight line and a plurality of teeth extending from the back yoke forming portion in a direction intersecting the direction in which the back yoke forming portion extends. For example, Patent Document 1 discloses a method for manufacturing a laminated core, which includes a step of cutting out a core assembly from a steel sheet, the core assembly including a plurality of core sheets each having a back yoke portion and teeth protruding from the back yoke portion arranged in a straight line, and a plurality of linking portions for linking the plurality of core sheets are provided between the core sheets.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-44885 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the manufacturing method disclosed in Patent Document 1, the two core sheet assemblies are punched out from a steel plate in an arrangement where the teeth of the two core sheet assemblies mesh with each other. This can reduce material loss of the steel plate piece.

[0008] However, the front end portion of the teeth of the core sheet has a pair of protrusions protruding to one side and the other side in the width direction of the teeth. Therefore, in the manufacturing method of Patent Document 1, it is necessary to increase the gap size of the multiple teeth of each core sheet assembly of the steel plate sheet in accordance with the width size of the pair of protrusions. Therefore, in the manufacturing method of Patent Document 1, the waste portion of the material generated between the teeth of the two core sheet assemblies increases, and there is a problem of reduced material yield when manufacturing a laminated core. Therefore, a manufacturing method is required to further improve the yield of electromagnetic steel sheets when manufacturing laminated cores.

[0009] An object of the present invention is to provide a method for manufacturing a laminated iron core that can improve the yield of electromagnetic steel sheets when manufacturing the laminated iron core.

[0010] Means for solving problems

[0011] A method for manufacturing a laminated core according to an embodiment of the present invention is a method for manufacturing a laminated core in which a plate-shaped back yoke portion and a plurality of plate-shaped teeth are stacked in a thickness direction. The method for manufacturing a laminated core comprises: a punching step in which a steel plate is punched to form a back yoke forming portion extending in one direction and the plurality of teeth, wherein when the steel plate is viewed in the thickness direction, the plurality of teeth extend from the back yoke forming portion in a direction intersecting the one direction; and a bending step in which the back yoke forming portion formed in the punching step is bent into an arc shape when viewed in the thickness direction to form the back yoke portion. In the punching step, a pair of protrusions are formed at the front end portions of the plurality of teeth, protruding in one direction and the other direction in the width direction of the teeth, respectively, and when the steel plate is viewed in the thickness direction, a recess is formed in a portion in which the size of the gap between the plurality of teeth and the teeth located next to each other is smaller than the size of the pair of protrusions in the width direction of the teeth, and the recess is recessed in the width direction and has a recessed area larger than the protrusion.

[0012] A laminated core according to one embodiment of the present invention is a cylindrical laminated core, wherein the laminated core is respectively laminated in the thickness direction: a plurality of plate-shaped teeth extending in the radial direction of a central axis and arranged in the circumferential direction with the central axis as the center; and a plate-shaped back yoke portion, which connects the plurality of teeth in the circumferential direction at the end of the radial direction. The plurality of teeth have a pair of protrusions protruding in one direction and the other direction of the width direction of the teeth at the front end. When the teeth are observed in the thickness direction, when the circumferential interval between the tooth center lines extending in the radial direction through the center of the width direction of the plurality of teeth is set as the circumferential interval on the outer peripheral side of the back yoke portion as the tooth-to-tooth distance, when the teeth are observed from the thickness direction, the plurality of teeth have a recessed portion in a portion where the size obtained by subtracting the size of the width direction of the teeth from the tooth-to-tooth distance is smaller than the size of the width direction of the pair of protrusions of the teeth, and the recessed portion is recessed in the width direction and has a recessed area larger than the protrusion.

[0013] Effects of the Invention

[0014] According to the method for manufacturing a laminated core according to one embodiment of the present invention, for example, it is possible to improve the yield rate of steel sheets when manufacturing the laminated core. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view showing a schematic structure of a laminated core.

[0016] Figure 2 It is a plan view showing a schematic structure of a laminated core.

[0017] Figure 3 yes Figure 2A partial enlarged view of .

[0018] Figure 4 This is an enlarged view of the concave portion.

[0019] Figure 5 1 is a flowchart showing a method for manufacturing a laminated core.

[0020] Fig. 6A It is a plan view of the steel plate showing the arrangement of the back yoke forming portion and the teeth of the steel plate.

[0021] Figure 6B yes Fig. 6A A partial enlarged view of .

[0022] Figure 7 This is a top view of the back yoke forming portion and multiple teeth punched out from a steel plate.

[0023] Figure 8 This is a diagram for explaining a state in which a back yoke forming portion punched out from a steel plate is laminated while being bent. DETAILED DESCRIPTION

[0024] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same or corresponding parts in the drawings are marked with the same reference numerals, and their descriptions will not be repeated. In addition, the dimensions of the components in each figure do not faithfully show the dimensions of the actual components and the dimensional ratios of the components.

[0025] In the following description, the direction parallel to the center axis P of the laminated core is referred to as the "axial direction", the direction orthogonal to the center axis P is referred to as the "radial direction", and the direction along the arc centered on the center axis P is referred to as the "circumferential direction".

[0026] In the following description, in a plate-like component, the direction of the plate thickness is referred to as the "thickness direction" of the component. "Observing the component in the thickness direction" means that the thickness direction is consistent with the direction of sight. For example, "observing the steel plate 100 in the thickness direction" means observing the surface of the steel plate 100 from a position away from the steel plate 100 in the thickness direction.

[0027] In the following description, the direction perpendicular to the extending direction of the tooth 4 extending from the back yoke portion 3 and the back yoke forming portion 103 is referred to as the "width direction" of the tooth 4. The "dimension in the width direction of the tooth" refers to the distance between a pair of tooth side surfaces 4c extending linearly on both sides in the width direction of the tooth 4. The dimension in the width direction of the tooth at the position where the recess 6 is formed on the tooth 4 refers to the dimension between a pair of extension lines of the tooth side surface 4c relative to the recess 6.

[0028] In addition, in the following description, expressions such as "fixed", "connected" and "mounted" (hereinafter referred to as fixed, etc.) include not only cases where components are directly fixed to each other, but also cases where components are fixed via other components. That is, in the following description, expressions such as fixed include the meaning of direct and indirect fixing of components to each other.

[0029] (Implementation Method)

[0030] (Structure of laminated core)

[0031] The laminated core 1 of the exemplary embodiment of the present invention is manufactured by the manufacturing method of the exemplary laminated core 1 described later. By manufacturing the laminated core 1 by the manufacturing method described later, the yield rate of the electromagnetic steel sheet which is the material of the laminated core 1 can be improved. That is, the laminated core 1 is manufactured by the manufacturing method which can improve the yield rate of the material.

[0032] First, refer to Figures 1 to 4 , the structure of the laminated core 1 is described. Figure 1 As shown, the laminated core 1 is cylindrical. In the present embodiment, the laminated core 1 is formed by a spiral process in which a strip-shaped core sheet 2 punched into a predetermined shape is spirally wound while being bent into an arc shape when viewed in the thickness direction.

[0033] like Figure 1 and Figure 2 As shown, in this embodiment, the core sheet 2 includes: a back yoke 3 extending in the circumferential direction of the laminated core 1 ; and a plurality of teeth 4 extending from the back yoke 3 toward the central axis P of the laminated core 1 .

[0034] like Figure 2 As shown, when the laminated core 1 is observed in the axial direction, the back yoke portion 3 is annular. The back yoke portion 3 has an outer peripheral surface 3a constituting the outer peripheral surface of the laminated core 1, and an inter-tooth inner peripheral surface 3b extending in the circumferential direction between the base end sides of adjacent teeth 4. The back yoke portion 3 has a slit 3c extending from the inter-tooth inner peripheral surface 3b to the outer peripheral surface 3a.

[0035] Figure 3 yes Figure 2 An enlarged view of the portion enclosed by the dashed line. Figure 3 As shown, in this embodiment, the plurality of teeth 4 are trapezoidal in shape with the width L1 decreasing from the radially outer side to the radially inner side. The size of the gap between the circumferentially adjacent teeth 4 is equal in the radially outer side and the radially inner side.

[0036] In addition, the details will be described later. Figure 7As shown, the plurality of teeth 4 extend in the same direction in a state of being punched out from an electromagnetic steel sheet. In a state of being punched out from an electromagnetic steel sheet, the size of the gap between the tip ends 4a of the plurality of teeth 4 is larger than the size of the gap between the tip ends 4a of the teeth in the laminated core 1. In a state of being punched out from an electromagnetic steel sheet, the gap between the plurality of teeth 4 and the adjacent teeth 4 is a trapezoidal shape in which the size of the gap decreases as it moves from the tip end 4a side toward the base end 4b side.

[0037] When the teeth 4 are viewed in the thickness direction, the tooth center lines P1 extending radially through the width center of the plurality of teeth 4 have a circumferential spacing L2 as the circumferential spacing on the outer circumference of the back yoke 3. Figure 7 As shown, the tooth-to-tooth distance L2 is the interval between center lines P2 passing through the centers in the width direction of the plurality of teeth 4 extending in the same direction in a state of being punched out from an electromagnetic steel sheet.

[0038] like Figure 3 As shown, the plurality of teeth 4 have a pair of protrusions 5 at the radially inner end, that is, the front end 4a, which protrude in one direction and the other direction in the width direction of the teeth 4. The width direction dimension of the pair of protrusions 5 is L3.

[0039] The plurality of teeth 4 have recessed portions 6 recessed in the width direction of the teeth 4 at the base end portion 4b as the boundary portion with the back yoke 3. In the present embodiment, each tooth 4 has recessed portions 6 on both sides in the width direction of the base end portion 4b.

[0040] The teeth 4 have radially extending tooth side surfaces 4c between the protrusion 5 and the recess 6 at one end and between the protrusion 5 and the recess 6 at the other end. The corners between the tooth side surfaces 4c and the recess 6 are curved when viewed in the thickness direction.

[0041] In the present embodiment, the recessed portion 6 is located at the base end portion 4b of the tooth 4. The recessed portion 6 has a size to accommodate the protruding portion 5. That is, the recessed portion 6 has a larger recessed area than the protruding portion 5.

[0042] Figure 4 Yes Figure 3 The portion surrounded by the dotted line is enlarged in the figure. In the present embodiment, when the tooth 4 is observed in the thickness direction, the recess 6 has a protrusion 61 protruding toward the inside of the recess 6. The inner surface of the recess 6, except for the front end 61a of the protrusion 61, is generally in a curved shape that is recessed in the width direction of the tooth 4. In the present embodiment, the front end 61a of the protrusion 61 is located at a position closer to the front end side of the tooth 4 than the center position of the recess 6 in the radial direction of the laminated core 1.

[0043] Specifically, when viewed in the thickness direction, the first curved portion 62, the bottom surface 6a of the recess 6, and the fourth curved portion 65 are formed on the side of the back yoke 3 from the front end 61a of the protrusion 61. The first curved portion 62 is located between the front end 61a of the protrusion 61 and the bottom surface 6a, and is in a curved shape that is recessed toward the tooth 4. The fourth curved portion 65 is located between the bottom surface 6a and the inner peripheral surface 3b between the teeth, and is in a curved shape that is recessed toward the tooth 4.

[0044] The front end side of the tooth 4 closer to the front end 61a of the protrusion 61 is composed of the second curved portion 63 and the third curved portion 64. The second curved portion 63 is a portion from the front end 61a of the protrusion 61 toward the opening direction of the recess 6, and is a curved shape that is recessed toward the tooth 4 side. The third curved portion 64 is located between the second curved portion 63 and the tooth side surface 4c, and is a curved shape that is convex to the outside of the tooth 4. The second curved portion 63 and the third curved portion 64 are continuous. Therefore, when the tooth 4 is viewed in the thickness direction, the inner surface of the front end side of the tooth 4 closer to the front end 61a of the protrusion 61 is S-shaped.

[0045] In the present embodiment, the plurality of teeth 4 have the recessed portion 6 at the base end portion 4b. However, at least one of the plurality of teeth 4 may have the recessed portion 6 at the front end side of the tooth relative to the base end portion 4b. Specifically, the plurality of teeth 4 may have the recessed portion 6 recessed in the width direction at a portion whose dimension obtained by subtracting the dimension L1 of the width direction of the tooth from the inter-tooth distance L2 is smaller than the dimension L3 of the width direction of the pair of protrusions 5 of the tooth 4. The details of the position of the recessed portion 6 will be described later.

[0046] (Method for manufacturing laminated core)

[0047] Next, use Figures 5 to 8 An exemplary method of manufacturing the laminated core 1 having the above-described structure will be described in detail.

[0048] Figure 5 1 is a flowchart showing an example of a method for manufacturing the laminated iron core 1. Figure 5 As shown, the method for manufacturing the laminated core 1 includes a preparation step S1 , a punching step S2 , a bending step S3 , and a lamination step S4 .

[0049] First, in the preparation step S1, an electromagnetic steel sheet as a magnetic material is prepared. In the present embodiment, the electromagnetic steel sheet is in the form of a strip that is long in one direction. In addition, hereinafter, the electromagnetic steel sheet is referred to as a steel sheet 100. In addition, in the following description, the one direction is referred to as a first direction of the steel sheet 100, and a direction intersecting the first direction when the steel sheet 100 is observed in the thickness direction is referred to as a second direction of the steel sheet 100.

[0050] Next, in the punching step S2 , the steel plate 100 is punched out to form two band-shaped core sheet forming portions 102 . Fig. 6A1 is a diagram showing the arrangement of two core sheet forming portions 102 of a steel plate 100 . Figure 6B It is enlarged to show Fig. 6A The part of the diagram surrounded by the dotted line. Fig. 6A and Figure 6B In the figure, for the sake of convenience, the blanking area of ​​the steel plate 100 is marked with oblique lines. The blanking step S2 is performed by punching. That is, in the blanking step S2, a punch is used to punch. Fig. 6A The area with diagonal lines in the middle. Detailed description of the punching process is omitted.

[0051] In the punching step S2, a linear first region R1 having a predetermined width, which constitutes a boundary between two core sheet forming portions 102, is punched out on the steel plate 100. Thus, two strip-shaped core sheet forming portions 102 each having a back yoke forming portion 103 extending in a first direction and a plurality of teeth 4 extending from the back yoke forming portion 103 in a second direction are formed.

[0052] Specifically, if Fig. 6A As shown, in the punching step S2, a pair of back yoke forming parts 131 and 132 are formed which are arranged in the second direction and extend in the first direction. In addition, in the punching step S2, a plurality of first teeth 41 extending from the back yoke forming part 131 in the second direction and a plurality of second teeth 42 extending from the back yoke forming part 132 in the second direction are alternately formed side by side along the first direction between the pair of back yoke forming parts 131 and 132. Thus, two strip-shaped core sheet forming parts 121 and 122 are formed.

[0053] In addition, in the punching step S2, the first region R1 of the steel plate 100 is punched, and a pair of protrusions 5 are formed on each tooth 4, and a pair of recesses 6 are formed. Specifically, a pair of protrusions 5 protruding in one direction and the other direction of the width direction of the teeth are formed at the front end portion 4a of the plurality of teeth 4. In addition, a recess 6 is formed at the base end portion 4b of each tooth 4, and the recess 6 is recessed in the width direction and has a larger recessed area than the protrusion 5.

[0054] Specifically, if Fig. 6A As shown, in the punching step S2, the recessed portion 6 is formed in each of the first tooth 41 and the second tooth 42. In addition, in the punching step S2, in the steel plate 100, one of the pair of protrusions 5 of the second tooth 42 is formed inside the recessed portion 6 of the first tooth 41, and one of the pair of protrusions 5 of the first tooth 41 is formed inside the recessed portion 6 of the second tooth 42.

[0055] Through the punching step S2 described above, a plurality of second teeth 42 extending from the back yoke forming portion 132 can be formed in the region between the plurality of first teeth 41 extending from the back yoke forming portion 131 in the steel plate 100. In addition, the protrusion 5 of the second teeth 42 can be formed in the region inside the recess 6 formed in the first teeth 41. Therefore, a combination of a pair of back yoke forming portions 103 and a plurality of teeth 4 can be punched out efficiently from the steel plate 100. Therefore, the material yield can be improved.

[0056] In addition, in the punching step S2, a second region R2 extending in the second direction is punched out in the steel plate 100 in the region where the back yoke forming portion 103 is formed, thereby forming a plurality of slit forming portions 103a. Specifically, by punching out the second region R2, a plurality of pairs of opposing slit forming portions 103a are formed in the back yoke forming portion 103. By the bending step S3 described later, the pair of slit forming portions 103a are brought into contact with each other, thereby forming the slits 3c of the core sheet 2 in the laminated core 1.

[0057] In addition, in the punching step S2, the third region R3 of the steel plate 100 is punched to form a portion that becomes the outer peripheral surface 3a of the back yoke portion 3 in the laminated core 1. The second region R2 may be punched before the first region R1 is punched, or after the first region R1 is punched. The third region R3 may be punched before the first region R1 is punched, or after the first region R1 is punched. The second region R2 and the third region R3 may be punched together with the first region R1. Figure 7 Two core sheet forming portions 102 formed in the punching step S2 are shown.

[0058] Next, in the bending process S3, the back yoke forming part 103 of one of the two iron core forming parts 102 formed in the punching process S2 is bent into a circular arc shape when viewed in the thickness direction. Specifically, a pair of slit forming parts 103a of the back yoke forming part 103 formed by punching the second region R2 are brought into contact with each other. Therefore, the length dimension of one side of the two ends of the back yoke forming part 103 extending in the length direction on which the plurality of teeth 4 are formed can be made smaller than the length dimension of the outer peripheral side. Therefore, a back yoke forming part 103 that is bent into a circular arc shape when viewed in the thickness direction is formed.

[0059] Then, in the lamination step S4 , the arc-bent back yoke forming portion 103 is spirally wound and laminated to obtain the laminated core 1 in which the plate-like back yoke portion 3 and the plurality of plate-like teeth 4 are laminated in the thickness direction.

[0060] (Method for forming concave portion)

[0061] Next, refer to Figure 4 , Fig. 6A and Figure 6B, the method for forming the recessed portion 6 is described in detail. The method for forming the pair of recessed portions 6 of the first tooth 41 is the same as the method for forming the pair of recessed portions 6 of the second tooth 42. Therefore, the method for forming only one of the pair of recessed portions 6 of the first tooth 41 is described below.

[0062] As described above, in the punching step S2, the first region R1 of the steel sheet 100 is punched. The first region R1 is a linear region that separates one core sheet forming portion 121 and the other core sheet forming portion 122 of the two core sheet forming portions 102. Figure 6B As shown, the first region R1 is a region having a plurality of curved portions between the recessed portion 6 of the first tooth 41 and the protruding portion 5 of the second tooth 42 .

[0063] The recess 6 of the laminated core 1 has corners located on both sides of the bottom surface 6a of the recess 6 and a corner on the front end side of the first tooth 41 in the recess 6. Therefore, in order to form the recess 6, a region having three curved portions needs to be punched out.

[0064] In the present embodiment, the punching step S2 includes at least two steps of a first punching step and a second punching step. That is, in the present embodiment, the recessed portion 6 is formed by two punching steps.

[0065] In the present embodiment, in the first punching step, at least the portion on the front end side of the first tooth 41 in the inner surface of the recess 6 is formed. Specifically, in the first punching step, the front end side region R11 as a part of the first region R1 is punched to form the portion on the front end side of the first tooth 41 of the recess 6 of the first tooth 41.

[0066] like Figure 6B As shown, the front end side region R11 includes a portion extending in the second direction of the steel plate 100 and a portion extending toward the bottom surface 6a of the recess 6. The front end side region R11 has a curved front end side bent portion R64 between the portion extending in the second direction and the portion extending toward the bottom surface 6a. The front end side bent portion R64 forms a corner portion of the front end side of the first tooth 41 in the recess 6. Figure 4 As shown, the third curved portion 64 of the recess 6 in the core sheet 2 of the laminated core 1 is formed by the front end side bent portion R64.

[0067] In addition, the front end region R11 has a curved front end curved portion R63 at the front end of the portion extending toward the bottom surface 6a. Figure 4 As shown, the second curved portion 63 of the recessed portion 6 in the core sheet 2 of the laminated core 1 is formed by the front end side curved portion R63.

[0068] In the second punching step, at least the base end side portion of the first tooth 41 is formed in the inner surface of the recess 6. Specifically, in the second punching step, the base end side region R12 as a part of the first region R1 is punched to form the base end side portion of the recess 6 of the first tooth 41.

[0069] like Figure 6B As shown in FIG. 1 , the base end region R12 includes a portion extending toward the bottom surface 6a of the recess 6 and a portion extending along the bottom surface 6a of the recess 6. The base end region R12 has a curved base end curved portion R65 between the portion extending toward the bottom surface 6a and the portion extending along the bottom surface 6a of the recess 6. The base end curved portion R65 forms a corner portion on the side of the back yoke forming portion 131 of the corner portions located on both sides of the bottom surface 6a of the recess 6. That is, as shown in FIG. Figure 4 As shown, the fourth curved portion 65 of the recessed portion 6 in the core sheet 2 of the laminated core 1 is formed by the base end side bent portion R65 .

[0070] In addition, the base end region R12 has a base end curved surface R62 at the tip of the portion extending along the bottom surface 6a. Figure 4 As shown, the first curved portion 62 of the recessed portion 6 in the core sheet 2 of the laminated core 1 is formed by the base end side curved surface portion R62 .

[0071] like Figure 6B As shown, the end of the front end region R11 and the end of the base end region R12 overlap when viewed in the thickness direction at the position of the corner of the front end side of the first tooth 41 in the corners located on both sides of the bottom surface 6a of the recessed portion 6. That is, the corner of the front end side is formed by the end of the front end region R11 and the end of the base end region R12.

[0072] As described above, by forming the recessed portion 6 in the first punching step and the second punching step, three curved portions can be easily formed between the recessed portion 6 of the first tooth 41 and the protruding portion 5 of the second tooth 42 .

[0073] Furthermore, by forming the recessed portion 6 in two steps, the first punching step and the second punching step, the area of ​​the steel plate 100 punched at one time can be reduced when forming the recessed portion 6. This can disperse the force when punching the steel plate 100. Therefore, the recessed portion 6 can be easily formed.

[0074] In the case where the corner of the recess 6 is formed by the overlapping portion of the front end region R11 punched in the first punching process and the base end region R12 punched in the second punching process, the overlapping portion of the front end region R11 and the base end region R12 is small. In the case where the overlapping portion of the front end region R11 and the base end region R12 is small, the protrusion 61 is formed at the boundary portion between the front end region R11 and the base end region R12. That is, the steel plate 100 is punched by the punching process that can easily form the recess 6, so that the protrusion 61 protruding toward the inside of the recess 6 is formed in the recess 6. Therefore, by punching the steel plate 100 by the punching process that forms the protrusion 61 protruding toward the inside of the recess 6 in the recess 6, the recess 6 can be easily formed.

[0075] In addition, the protrusion 61 in the recess 6 is formed at the portion where the front end side region R11 overlaps with the base end side region R12. As described above, the front end side region R11 and the base end side region R12 overlap at the corner portion on the front end side of the first tooth 41 of the recess 6. Therefore, the protrusion 61 is formed at a position closer to the front end side of the first tooth 41 than the center position of the recess 6 in the second direction. That is, the recess 6 can be easily formed by punching the steel plate 100 in the punching process, in which the protrusion 61 protruding toward the inside of the recess 6 is formed in the recess 6 at a position closer to the front end side of the first tooth 41 than the center position of the recess 6 in the second direction.

[0076] In addition, in the present embodiment, the portion on the front end side of the teeth 4 in the inner surface of the recessed portion 6 is formed by the first punching step, and the portion on the base end side of the teeth 4 in the inner surface of the recessed portion 6 is formed by the second punching step. However, the portion on the base end side of the teeth 4 in the inner surface of the recessed portion 6 may be formed by the first punching step, and the portion on the front end side of the teeth 4 in the inner surface of the recessed portion 6 may be formed by the second punching step.

[0077] By the above-mentioned method for manufacturing the laminated iron core 1, it is possible to obtain Figures 1 to 4 The laminated core 1 shown in FIG. 1 has a recessed portion 6 in the base end portion 4b of the plurality of teeth 4. In addition, by the manufacturing method of the laminated core 1 of the present embodiment, it is possible to obtain a laminated core 1 having a protrusion 61, a first curved portion 62, a second curved portion 63, a third curved portion 64, and a fourth curved portion 65 in the recessed portion 6. In the manufacturing method of the laminated core 1 of the present embodiment, it is possible to improve the yield rate of the steel plate 100 when manufacturing the laminated core 1. That is, the laminated core 1 of the present embodiment is manufactured by a manufacturing method that improves the yield rate of the material.

[0078] Next, refer to Figure 3 and Fig. 6A, the positions of the recessed portions 6 of the plurality of teeth 4 will be described. In the present embodiment, in the punching step S2, the recessed portions 6 are formed in the base end portions 4b of the respective teeth 4. However, in the punching step S102, the recessed portions may be formed in the plurality of teeth in the portions where the dimension L11 of the gap between the teeth located next to each other is smaller than the dimension L12 of the pair of protrusions in the teeth in the width direction.

[0079] Thus, the second teeth having the protruding portion can be formed in the remaining area after the plurality of first teeth are punched out on the steel plate 100 without interfering with the first teeth. That is, the protruding portion of the second teeth can be formed in the remaining area after the recessed portion is formed in the steel plate 100, and the second teeth can be formed in the area between the plurality of first teeth when the plurality of first teeth are punched out in the steel plate 100. Therefore, the yield rate of the steel plate can be improved when manufacturing the laminated core.

[0080] The dimension L11 of the gap in the core sheet forming portion 102 can be obtained by subtracting the dimension L1 of the width direction of the teeth 4 from the interval L13 in the first direction between center lines P2 passing through the centers of the teeth 4 in the core sheet forming portion 102 in the width direction.

[0081] Therefore, in the core sheet 2 where the back yoke 3 is bent, as shown in FIG. Figure 3 As shown, by subtracting the dimension L1 of the width direction of the tooth 4 from the inter-tooth distance L2, the dimension L11 of the gap between adjacent teeth 4 during manufacturing can be obtained. That is, by forming a recessed portion at the above position in the tooth, a laminated core can be obtained in which the recessed portion is located at a portion where the dimension obtained by subtracting the dimension L1 of the width direction of the tooth from the inter-tooth distance L2 is smaller than the dimension of the width direction of a pair of protrusions 5 in the tooth 4. Therefore, a laminated core manufactured by a manufacturing method with an improved yield of the steel plate 100 can be provided.

[0082] In addition, as in the present embodiment, in the punching step S2, it is preferred that the recessed portion 6 is formed in the base end portion 4b of the plurality of teeth 4. By forming the recessed portion 6 in the base end portion 4b of each tooth 4, the protrusion 5 located at the front end of the plurality of teeth 4 extending from the other back yoke forming portion 103 can be formed in the area remaining after the recessed portion 6 is punched out in the base end portion 4b of the plurality of teeth 4 in the steel plate 100. Therefore, the two core sheet forming portions 102 can be formed at positions close to the steel plate 100 in the second direction, and thus the material yield can be further improved.

[0083] As described above, the method for manufacturing the laminated core 1 according to the embodiment can have the following features.

[0084] (1) A method for manufacturing a laminated iron core 1, wherein the laminated iron core 1 has a plate-shaped back yoke portion 3 and a plurality of plate-shaped teeth 4 stacked in a thickness direction, the method comprising: a punching step S2, in which a steel plate 100 is punched to form a back yoke forming portion 103 extending in one direction, and a plurality of teeth 4, wherein when the steel plate 100 is observed in the thickness direction, the plurality of teeth 4 extend from the back yoke forming portion 103 in a direction intersecting the one direction; and a bending step S3, in which the back yoke formed in the punching step S2 is bent The portion 103 is bent into an arc shape when viewed in the thickness direction to form the back yoke portion 3, and in the punching process S2, a pair of protrusions 5 are formed at the front end portions 4a of the plurality of teeth 4, respectively protruding to one side and the other side of the width direction of the teeth 4, and when the steel plate 100 is observed in the thickness direction, in the plurality of teeth 4, a recess 6 is formed in a portion where a dimension L11 of a gap with each of the teeth located next to each other is smaller than a dimension L12 of the pair of protrusions 5 in the width direction of the tooth 4, and the recess 6 is recessed in the width direction and has a recessed area larger than the protrusion 5.

[0085] In the manufacturing method, the back yoke forming portion 103 extending in one direction and the plurality of teeth 4 extending in a direction intersecting the one direction are formed by the punching step S2. In addition, in the punching step S2, the protrusions 5 protruding in one direction and the other direction in the width direction are formed at the front end portions 4a of the plurality of teeth 4. In addition, in the punching step S2, the recessed portion 6 having a larger recessed area than the protrusion 5 is formed in the plurality of teeth 4 at the portion where the dimension L11 of the gap with the teeth 4 located next to each other is smaller than the dimension L12 of the pair of protrusions 5 in the width direction.

[0086] Thus, other teeth 4 having protrusions 5 can be formed in the remaining area after the plurality of teeth 4 are punched out of the steel plate 100. That is, the protrusions 5 of other teeth 4 can be formed in the remaining portion after the recesses 6 are formed in the steel plate 100, and other teeth 4 can be formed in the area between the plurality of teeth 4 when the plurality of teeth 4 are punched out of the steel plate 100. Therefore, the yield rate of the steel plate 100 when manufacturing the laminated core 1 can be improved.

[0087] (2) In the manufacturing method of the laminated iron core 1 described in (1), in the punching step S2, a pair of the back yoke forming portions 131 and 132 are formed so as to be arranged in a direction intersecting the one direction, and between the pair of the back yoke forming portions 131 and 132, a plurality of first teeth 41 extending from one back yoke forming portion 131 and a plurality of second teeth 42 extending from the other back yoke forming portion 132 are formed alternately in the one direction, the recesses 6 are formed in the first teeth 41 and the second teeth 42, respectively, and, in the steel plate 100, one of the pair of protrusions 5 of the second tooth 42 is formed inside the recess 6 of the first tooth 41, and one of the pair of protrusions 5 of the first tooth 41 is formed inside the recess 6 of the second tooth 42.

[0088] Therefore, in the steel plate 100, the plurality of second teeth 42 extending from the back yoke forming portion 132 can be formed in the region between the plurality of first teeth 41 extending from the back yoke forming portion 131. In addition, the protrusion 5 of the second teeth 42 can be formed in the region inside the recess 6 formed in the first teeth 41. Therefore, the combination of a pair of back yoke forming portions 103 and the plurality of teeth 4 can be efficiently punched out from the steel plate 100. Therefore, the material yield can be improved.

[0089] (3) In the method for manufacturing the laminated core 1 described in (1) or (2), in the punching step S2 , the recessed portions 6 are formed in the base end portions 4 b of the plurality of teeth 4 .

[0090] Thus, the protrusion 5 located at the front end of the plurality of teeth 4 extending from the other back yoke forming portion 103 can be formed in the steel plate 100 in the remaining area after the recess 6 is punched out at the base end portion 4b of the plurality of teeth 4. Therefore, the two core sheet forming portions 102 can be formed at positions close to the steel plate 100 in the second direction, so that the material yield can be further improved.

[0091] (4) In the manufacturing method of the laminated iron core described in any one of (1) to (3), the punching process S2 includes: a first punching process, in which at least a portion of the front end side of the tooth 4 and at least a portion of the base end side of the tooth 4 in the inner surface of the recess 6 are formed; and a second punching process, in which the remaining portion of the inner surface of the recess 6 is formed, and a protrusion protruding toward the inside of the recess is formed at a boundary portion of the inner surface of the recess with the portion formed in the first punching process.

[0092] By forming the recessed portion 6 in two steps, the first punching step and the second punching step, the area of ​​the steel plate 100 punched out at one time can be reduced when forming the recessed portion 6. This can disperse the force when punching the steel plate 100, so that the recessed portion 6 can be easily formed.

[0093] From the overlapping portion of the region Ra punched in the first punching process and the region Rb punched in the second punching process, when the direction in which the region Ra extends is different from the direction in which the region Rb extends, the corner can be easily formed using the overlapping portion. Therefore, the corner of the recess 6 can be formed by the overlapping portion of the region Ra and the region Rb. In this case, the overlapping portion of the region Ra and the region Rb is small. When the overlapping portion of the region Ra and the region Rb is small, a protrusion 61 is formed at the boundary portion between the region Ra and the region Rb. That is, the steel plate 100 is punched by a punching process that can easily form the corner of the recess 6, so that the protrusion 61 protruding toward the inside of the recess 6 is formed in the recess 6. Therefore, by punching the steel plate 100 using a punching process that forms the protrusion 61 protruding toward the inside of the recess 6 in the recess 6, the recess 6 can be easily formed.

[0094] In addition, the laminated core 1 according to the embodiment can have the following features.

[0095] (5) A laminated iron core 1, which is a cylindrical laminated iron core 1, wherein the laminated iron core 1 is respectively laminated with a plurality of plate-shaped teeth 4 and a plate-shaped back yoke 3 in the thickness direction, wherein the plurality of teeth 4 extend in the radial direction of a central axis P and are arranged in the circumferential direction with the central axis P as the center, wherein the back yoke 3 connects the plurality of teeth 4 in the circumferential direction at the end portion in the radial direction, wherein the plurality of teeth 4 have a pair of protrusions 5 protruding in one direction and the other direction in the width direction of the teeth 4 at the front end portion 4a, and when the teeth 4 are observed in the thickness direction, when the plurality of teeth 4 are passed through the back yoke 3, the plurality of teeth 4 are respectively protruded in one direction and the other direction in the width direction of the teeth 4. In a case where the circumferential interval between the centers of the width direction of the teeth 4 and the tooth center lines P1 extending radially, which are circumferentially spaced from each other and on the outer peripheral side of the back yoke 3, is set as the tooth distance L2, when the teeth 4 are observed along the thickness direction, the multiple teeth 4 have a recess 6 in a portion where the size obtained by subtracting the dimension L1 of the width direction of the teeth 4 from the tooth distance L2 is smaller than the dimension L3 of the width direction of the pair of protrusions 5 of the tooth 4, and the recess 6 is recessed in the width direction and has a recessed area larger than the protrusion 5.

[0096] The laminated iron core 1 having the above-mentioned structure is a laminated iron core 1 obtained by forming other teeth 4 having protrusions 5 in the remaining area after punching out a plurality of teeth 4 on a steel plate 100. Therefore, the laminated iron core 1 is manufactured by a manufacturing method that improves the yield of the steel plate 100. Therefore, the laminated iron core 1 manufactured by a manufacturing method that improves the yield of the steel plate 100 can be provided.

[0097] (6) In the laminated core 1 described in (5), the recessed portion 6 is located at the base end portion 4 b of each of the plurality of teeth 4 .

[0098] Therefore, the laminated iron core 1 is a laminated iron core 1 obtained by forming the protrusion 5 in the area remaining after punching out the recess 6 in the base end portion 4b of the plurality of teeth 4 in the steel plate 100, and the protrusion 5 is located at the front end of the plurality of teeth 4 extending from the other back yoke forming portion 103. That is, the laminated iron core 1 is manufactured by a manufacturing method in which the material yield is further improved by forming the two core sheet forming portions 102 at positions close to the second direction of the steel plate 100. Therefore, the laminated iron core 1 manufactured by the manufacturing method in which the yield of the steel plate 100 is further improved can be provided.

[0099] (7) In the laminated core 1 described in (5) or (6), the recessed portion 6 has a protrusion 61 that protrudes toward the inside of the recessed portion 6 when the tooth 4 is viewed in the thickness direction.

[0100] The protrusion 61 of the laminated core 1 is formed by punching the steel plate 100 through two processes, namely, the first punching process and the second punching process. By forming the recess 6 through a plurality of punching processes, the recess 6 can be easily formed. Therefore, the laminated core 1 manufactured by the manufacturing method that can easily form the recess 6 can be provided.

[0101] (8) In the laminated iron core described in (7), when observing the tooth 4 along the thickness direction, the recess 6 has a first curved portion 62 that is recessed along the width direction on the side of the back yoke portion 3 closer to the protrusion 61, and has a second curved portion 63 that is recessed along the width direction on the front end side of the tooth 4.

[0102] The second curved portion 63 is formed by punching out a region having a curved surface portion in a curved surface shape at the end. That is, the second curved portion 63 is formed by a first punching process of punching out the front end side region R11 of the steel plate 100. The first curved portion 62 is formed by punching out a region having a curved surface portion in a curved surface shape at the end. That is, the first curved portion 62 is formed by a second punching process of punching out the base end side region R12 of the steel plate 100.

[0103] In addition, the protrusion 61 is formed at the boundary portion between the front end side region R11 punched out in the first punching step and the base end side region R12 punched out in the second punching step. That is, the steel plate 100 is punched out through the first punching step and the second punching step, thereby forming the recess 6 having the first curved portion 62, the second curved portion 63 and the protrusion 61. As described above, by punching out the steel plate 100 through the two punching steps, the recess 6 can be easily formed. Therefore, the laminated core 1 manufactured by the manufacturing method that can easily form the recess 6 can be provided.

[0104] (9) In the laminated core 1 described in (8), the plurality of teeth 4 have a third curved portion 64 on the front end side of the teeth 4 in the recess 6 when the teeth 4 are viewed in the thickness direction.

[0105] The third curved portion 64 is formed by punching out a region having a curved portion when the steel plate 100 is viewed in the thickness direction. That is, the third curved portion 64 is formed by punching out a region of the steel plate 100 having the curved portion. Therefore, by punching out a region of the steel plate 100 having the curved portion and the end portion, the third curved portion 64 can be formed while forming the second curved portion 63. In this way, the second curved portion 63 and the third curved portion 64 can be easily formed. Therefore, it is possible to provide a laminated core 1 manufactured by a manufacturing method that can easily form the second curved portion 63 and the third curved portion 64.

[0106] (10) In the laminated core 1 described in (9), the front end 61a of the protrusion 61 is located closer to the front end of the tooth 4 than the center position of the recess 6 in the radial direction, and the second curved portion 63 and the third curved portion 64 are continuous.

[0107] In the laminated core 1 described above, the front end 61a of the protrusion 61 is located near the corner of the front end side of the tooth 4 among the corners on both sides of the bottom surface 6a of the recess 6. In addition, as described above, the protrusion 61 is formed at the boundary portion of the area punched out in the first punching step and the area punched out in the second punching step. That is, the protrusion 61 is formed by punching out the front end side region R11 with the end facing the bottom surface 6a side of the recess 6 in the first punching step and the base end side region R12 with the end facing the front end side of the tooth 4 in the second punching step. As described above, the corner can be easily formed by the portion where the front end side region R11 and the base end side region R12 overlap. That is, by forming the recess 6 with the front end 61a of the protrusion 61 located near the corner, the corner of the recess 6 can be easily formed. Therefore, it is possible to provide a laminated core 1 manufactured by a manufacturing method that can easily form the recess 6.

[0108] (Other embodiments)

[0109] The embodiments of the present invention are described above, but the above embodiments are merely examples for implementing the present invention. Therefore, the present invention is not limited to the above embodiments, and the above embodiments can be appropriately modified and implemented within the scope of the present invention.

[0110] In the above embodiment, the laminated core 1 is formed by a spiral process in which the strip-shaped core sheets 2 are bent into an arc shape when viewed in the thickness direction and then spirally wound. However, the laminated core may be formed by stacking annular core sheets in the thickness direction.

[0111] In the above embodiment, the core sheet 2 has: a back yoke portion 3 extending in the circumferential direction of the laminated core 1; and a plurality of teeth 4 extending from the back yoke portion 3 toward the central axis P of the laminated core 1. However, the core sheet may also have a structure having a back yoke portion extending in the circumferential direction of the laminated core and a plurality of teeth extending from the back yoke portion toward the radially outer side of the laminated core 1.

[0112] In the above embodiment, the plurality of teeth 4 are in a trapezoidal shape in which the dimension L1 in the width direction decreases from the radial outer side toward the radial inner side. However, the plurality of teeth may also be in a rectangular shape in which the dimension in the width direction of the radial outer side is substantially the same as the dimension in the width direction of the radial inner side. In this case, the dimension of the gap between the teeth adjacent to each other in the circumferential direction is in a trapezoidal shape in which the dimension becomes smaller from the radial outer side toward the radial inner side.

[0113] In the embodiment, the first tooth 41 has the recessed portion 6 on both sides of the base end portion 4b in the width direction. However, the first tooth may have a recessed portion on one side of the base end portion in the width direction. In this case, one of the pair of protrusions of the second tooth can also be formed inside the recessed portion of the first tooth, so that a laminated core manufactured by a manufacturing method with improved yield of the steel plate 100 can be provided.

[0114] In the embodiment, the front end 61a of the protrusion 61 is located on the front end side of the tooth 4 relative to the center position of the recess 6 in the radial direction of the laminated iron core 1. However, the front end of the protrusion may be located on the rear yoke side relative to the center position of the recess in the radial direction of the laminated iron core. The front end of the protrusion may be located at the center position of the recess in the radial direction of the laminated iron core. The protrusion is formed when the recess is formed by a plurality of punching steps. By forming the recess by a plurality of punching steps, the recess can be easily formed. Therefore, the laminated iron core having the protrusion in the recess is manufactured by a manufacturing method that can easily form the recess.

[0115] In the punching step S2 of the embodiment, two core sheet forming parts 121 and 122 of the same shape are formed. That is, in the punching step S2, the recessed portion 6 is formed on each of the first tooth 41 and the second tooth 42. However, in the punching step, two core sheet forming parts having shapes different from each other may be formed. For example, a recessed portion may be formed on the teeth of one of the two core sheet forming parts, and no recessed portion may be formed on the teeth of the other core sheet forming part.

[0116] In the punching step S2 of the embodiment, the recessed portion 6 is formed on both sides of the base end portion 4b of each tooth 4 in the width direction. However, in the punching step, the recessed portion may be formed on one side of the base end portion of each tooth in the width direction. In this case, one of the pair of protrusions of the other core sheet forming portion may be formed inside the recessed portion of one of the two core sheet forming portions formed by the punching step. Therefore, the yield rate of the steel sheet when manufacturing the laminated core can be improved.

[0117] In the embodiment, the punching process S2 includes a first punching process and a second punching process. In the first punching process, the front end side region R11 of the first region R1 is punched to form at least a portion of the front end side of the first tooth 41 in the inner surface of the recess 6. In the second punching process, the base end side region R12 in the first region R1 is punched to form at least a portion of the base end side of the first tooth 41 in the inner surface of the recess 6. However, the first region R1 may be punched once in the punching process. In this case, the protrusion may not be formed on the inner surface of the recess. The first curved portion and the second curved portion may not be formed on the inner surface of the recess.

[0118] The present invention can be applied to a method for manufacturing a laminated core in which a back yoke extending linearly in the longitudinal direction of the electromagnetic steel sheet and a plurality of teeth extending in the width direction of the electromagnetic steel sheet are formed by punching a strip-shaped electromagnetic steel sheet.

[0119] Explanation of symbols

[0120] 1 laminated core; 2 core sheet; 3 back yoke; 3a outer peripheral surface; 3b inner peripheral surface between teeth; 3c slit; 4 tooth; 4a front end portion; 4b base end portion; 4c tooth side surface; 5 protrusion; 6 recess; 6a bottom surface; 41 first tooth; 42 second tooth; 61 protrusion; 61a front end; 62 first curved portion; 63 second curved portion; 64 third curved portion; 65 fourth curved portion; 100 steel plate; 102, 121, 122 core sheet forming portion; 103, 131, 132 back yoke forming portion; 10 3a slit forming portion; L1 dimension of the tooth in the width direction; L2 distance between teeth; L3, L12 dimension of the teeth of a pair of protruding portions in the width direction; L11 dimension of the gap between adjacent teeth; L13 interval between adjacent teeth in the steel plate; P1 tooth center line; P2 center line; R1 first region; R11 front end side region; R12 base end side region; R2 second region; R3 third region; R62 base end side curved portion; R63 front end side curved portion; R64 front end side curved portion; R65 base end side curved portion.

Claims

1. A method for manufacturing a laminated iron core, wherein a plate-shaped back yoke and a plurality of plate-shaped teeth are laminated in a thickness direction, characterized in that: have: a punching step in which a steel plate is punched to form a back yoke forming portion extending in one direction and the plurality of teeth, wherein the plurality of teeth extend from the back yoke forming portion in a direction intersecting the one direction when the steel plate is viewed in a thickness direction; as well as a bending step in which the back yoke forming portion formed in the punching step is bent into an arc shape when viewed from the thickness direction to form the back yoke portion, In the punching process, A pair of protrusions are formed at the front ends of the plurality of teeth, each protruding in one direction and the other direction in the width direction of the teeth, and When observing the steel plate in the thickness direction, among the multiple teeth, a recessed portion is formed in a portion where the size of the gap with the teeth located next to each other is smaller than the size of the pair of protrusions in the width direction of the tooth, and the recessed portion is recessed in the width direction and has a recessed area larger than the protrusion.

2. The method for manufacturing a laminated core according to claim 1, wherein: In the punching process, A pair of the back yoke forming parts are formed to be arranged in a direction intersecting the one direction, and a plurality of first teeth extending from one back yoke forming part and a plurality of second teeth extending from the other back yoke forming part are alternately arranged in the one direction between the pair of back yoke forming parts. The recessed portions are formed on the first tooth and the second tooth, respectively, and in the steel plate, one of the pair of protrusions of the second tooth is formed inside the recessed portion of the first tooth, and one of the pair of protrusions of the first tooth is formed inside the recessed portion of the second tooth.

3. The method for manufacturing a laminated core according to claim 1, wherein: In the punching process, The recessed portion is formed at base end portions of the plurality of teeth.

4. The method for manufacturing a laminated core according to any one of claims 1 to 3, characterized in that: The blanking process comprises: a first punching step in which at least one of a portion of the inner surface of the recessed portion on the tip end side of the tooth and a portion of the inner surface of the recessed portion on the base end side of the tooth is formed; and A second punching step is performed to form a remaining portion of the inner surface of the recess, and to form a protrusion protruding into the interior of the recess at a boundary portion between the inner surface of the recess and the portion formed in the first punching step.

5. A laminated iron core, which is a cylindrical laminated iron core, wherein the laminated iron core is respectively laminated in the thickness direction: a plurality of plate-shaped teeth extending in the radial direction of a central axis and arranged in the circumferential direction with the central axis as the center; and a plate-shaped back yoke portion, which connects the plurality of teeth in the circumferential direction at the end in the radial direction, The laminated core is characterized in that The plurality of teeth have a pair of protrusions at the front end portions, each protruding in one direction and the other direction in the width direction of the teeth. When the teeth are viewed in the thickness direction, the circumferential spacing of the tooth center lines extending in the radial direction through the centers of the plurality of teeth in the width direction is defined as the circumferential spacing on the outer peripheral side of the back yoke portion as the tooth spacing. When observing the teeth from the thickness direction, the multiple teeth have a recessed portion in a portion where the dimension obtained by subtracting the dimension of the teeth in the width direction from the distance between teeth is smaller than the dimension of the teeth in the width direction of the pair of protrusions of the teeth, and the recessed portion is recessed in the width direction and has a recessed area larger than the protrusion.

6. The laminated core according to claim 5, characterized in that The recessed portion is located at a base end portion of each of the plurality of teeth.

7. The laminated core according to claim 5 or 6, characterized in that: The recess has a protrusion that protrudes toward the inside of the recess when the tooth is viewed in the thickness direction.

8. The laminated core according to claim 7, characterized in that: When the tooth is viewed in the thickness direction, the recess has a first curved portion recessed in the width direction on the back yoke side relative to the protrusion, and has a second curved portion recessed in the width direction on the front end side of the tooth.

9. The laminated core according to claim 8, characterized in that The plurality of teeth have a third curved portion on a front end side of the teeth of the recessed portion when the teeth are viewed in the thickness direction.

10. The laminated core according to claim 9, characterized in that The front end of the protrusion is located closer to the front end of the tooth than the center position of the recess in the radial direction. The second curved portion and the third curved portion are continuous.

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