JP2017228722A - Iron core and manufacturing method and manufacturing apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an iron core capable of obtaining stable characteristics by suppressing an increases in iron loss and in exciting current, and a manufacturing method therefor and a manufacturing apparatus therefor.SOLUTION: An iron core 1 is formed into an annular shape having a corner portion and a straight portion by laminating thin plate-like magnetic materials 3. A length of an outer periphery in an annular state is longer than a value obtained by adding a value of 2π times as large as a laminated thickness of a magnetic material 3 in the straight portion to a length of an inner periphery.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an iron core formed by laminating thin plate-like magnetic materials, an iron core manufacturing method, and an iron core manufacturing apparatus.

  Conventionally, a wound core formed by laminating thin plate-like magnetic materials is known. Such a wound iron core is manufactured by cutting a circularly wound magnetic material, as disclosed in Patent Document 1, for example.

Japanese Patent Laying-Open No. 2015-8238

  However, when the iron core is excited, the temperature rises due to the iron loss that accompanies it, and the magnetic material expands. The iron loss increases when the magnetic flux density is high, and decreases when the magnetic flux density is low. In the case of a wound iron core, the magnetic flux density is higher at the outer periphery having a long magnetic path and a relatively large magnetic resistance, and lower at the inner periphery having a short magnetic path and a relatively small magnetic resistance. Therefore, in the wound iron core, the inner circumference is hotter than the outer circumference, and the thermal expansion is increased. That is, there is a difference in thermal expansion between the outer periphery and the inner periphery.

As a result, pressure in the direction of lamination of the magnetic material is generated at the corner portion, and when the magnetic materials 3 are pressed together, the interlayer resistance decreases, eddy current increases, and iron loss and excitation current increase. .
In the case of a so-called cut core, the pressure on the inner peripheral side is greater than that on the outer peripheral side on the horizontally polished facing surface. For this reason, an outer peripheral gap is expanded, and an event called fringing occurs in which the magnetic flux is detached from the iron core. As a result, iron loss and exciting current increase, making it difficult to obtain stable characteristics.
Thus, an iron core, a method for manufacturing an iron core, and an apparatus for manufacturing an iron core that can suppress the increase in iron loss and exciting current and obtain stable characteristics are provided.

  The iron core according to the embodiment is formed in a ring shape having a corner portion and a straight portion by laminating thin plate-like magnetic materials, and the length of the outer periphery in the annular state is set to the length of the inner periphery to the magnetic force in the straight portion. It is longer than the value obtained by adding 2π times the laminated thickness of the material.

The figure which shows the iron core of 1st Embodiment typically The figure which shows the manufacturing equipment of the iron core typically Diagram showing the flow of the iron core manufacturing process The figure which shows typically the magnetic material cut | disconnected in the cutting process. The figure which shows typically the laminated body which is a magnetic material laminated | stacked in the lamination process The figure which shows the aspect which shape | molds a laminated body in a formation process typically The figure which shows typically the aspect which adheres a laminated body in the adhering process. The figure which shows the manufactured iron core piece typically The figure which shows the iron core and molded object of 2nd Embodiment typically. The figure which shows the iron core and laminated body of 3rd Embodiment typically

Hereinafter, a plurality of embodiments will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated to the site | part substantially common in each embodiment.
(First embodiment)
Hereinafter, a first embodiment will be described with reference to FIGS. 1 to 8.

  As shown in FIG. 1, the iron core 1 is formed by combining two substantially U-shaped iron core pieces 2 at the opposing surface 2 a, and thereby a corner portion shown as an R portion in FIG. 1 and a straight line shown as an L portion in FIG. 1. And a generally annular shape having a portion. The iron core piece 2 is formed by laminating thin plate-like magnetic materials 3 and forming them in a substantially U shape. The opposing surfaces 2a are arranged so as to be parallel to each other, and a gap is formed at the same interval from the outer periphery to the inner periphery.

  The magnetic material 3 is formed by forming a ferrous amorphous material called a so-called amorphous core or a nanocrystalline material into a thin plate shape. The magnetic material 3 is generally formed by applying a molten raw material to a rotating cooling roll and rapidly cooling it, and has a ribbon shape with a thickness of about several tens of μm at the material stage. Such amorphous cores have been increasingly adopted in fields such as high-frequency transformers because they reduce iron loss and because the iron loss at high frequencies is smaller than the so-called silicon steel strip formed of silicon steel in a thin plate shape. Yes. In addition, the nanocrystal material is used particularly for high frequency applications.

  Now, as a comparison, a conventional so-called wound core will be described. A conventional wound iron core is formed by winding a magnetic material. In such a wound iron core, the magnetic material is cut at least at one place, and the one-turn cut core in which the cut places are shifted in stages, and the magnetic material is wound and fixed, and then cut into two parts. There is a cut core.

  However, in any of the wound cores, the laminated thickness of the magnetic material is constant in the state of being formed in an annular shape, and the corner portion and the straight portion have the same thickness. For this reason, when magnetic materials are laminated without gaps between layers as in a conventional wound iron core, the length of the outer circumference is a value obtained by adding 2π times the laminated thickness of the magnetic material in the straight portion to the length of the inner circumference. Will match. In other words, in the case of a conventional wound core, since there is no idea of creating a gap between the layers of the magnetic material, the magnetic material is wound or laminated so that there is no gap between the layers. Are formed in a similar shape.

On the other hand, in the iron core 1 of the present embodiment, the length of the outer periphery when formed in an annular shape is a value obtained by adding 2π times the lamination thickness (Ts) of the magnetic material 3 in the linear portion to the length of the inner periphery. Longer than. At this time, the laminated thickness of the iron core 1 in the straight portion is constant at Ts, whereas in the corner portion, the laminated thickness is larger than the laminated thickness (Ts) of the straight portion. More specifically, in the iron core 1, when the radius of the curved surface of the inner periphery in the corner portion is Ri and the distance from the center point to the outer periphery is Ro, the lamination thickness (Ro-Ri) of the corner portion is as follows: It is formed in a shape that satisfies the formula (1).
Ro-Ri> Ts (1)

  If the laminated thickness of the straight part is the same as that of a conventional wound core, the corner 1 has a shape in which the thickness of the corner part is slightly swollen as compared with the conventional wound core, that is, the magnetic material 3 in the corner part. A slight gap is formed between these layers. In other words, the iron core 1 is formed in a shape in which the inner periphery and the outer periphery of the corner portion are not similar. For this reason, in the case of the iron core 1, the dimensional change when the magnetic material 3 thermally expands can be absorbed to some extent in the corner portion by the gap in the corner portion. In FIG. 1, the magnetic material 3 and the gap formed between the layers are exaggerated from the actual one so that the above-described configuration becomes clear.

  The iron core 1 is manufactured by a manufacturing apparatus 10 as shown in FIG. The manufacturing apparatus 10 includes a cutting unit 11, a stacking unit 12, a forming unit 13, a fixing unit 14, a polishing unit 15, and a control unit 16 for controlling them. In addition, the arrow shown in FIG. 2 has shown the flow of the member.

  As will be described in detail later, the cutting unit 11 cuts the magnetic material 3 into a plurality of lengths. The cutting unit 11 is controlled by the control unit 16 and cuts the magnetic material 3 into a predetermined length and a plurality of different lengths. The cutting unit 11 may be configured to continuously change the length at the time of cutting, or may be configured to change the length to be cut after cutting a certain number of sheets. Moreover, the structure which cut | disconnects the magnetic material 3 to several length by providing the some cutting part 11 may be sufficient.

  The laminated portion 12 will be described in detail later, but when the magnetic material 3 having a plurality of cut lengths is formed into an annular shape, the length of the magnetic material 3 serving as the outer periphery is the inner periphery when formed into an annular shape. The magnetic material 3 is laminated so as to be longer than the length obtained by adding 2π times the laminated thickness (Ts) of the magnetic material 3 in the linear portion to the length of the magnetic material 3 to be formed.

As will be described in detail later, the forming unit 13 forms the laminated magnetic material 3 into a predetermined shape, in the case of this embodiment, a substantially U shape. In the following, the laminated magnetic material 3 is also referred to as a laminated body 20 (see FIG. 5) for convenience.
As will be described in detail later, the fixing portion 14 fixes the molded magnetic material 3 with an adhesive 30 (see FIG. 7A) and a resin 31 (see FIG. 7B).

Next, the operation of the above configuration will be described together with its manufacturing method.
FIG. 3 shows the main flow of the manufacturing process of the iron core 1. In this manufacturing process, first, a cutting process for cutting the magnetic material 3 is performed (S1). The magnetic material 3 is supplied to the cutting part 11 as a thin strip-shaped magnetic material strip 3a as shown in FIG. The magnetic material band 3 a is pulled out from the hoop 3 b in a wound state and supplied to the cutting part 11.

  Then, by cutting a plurality of magnetic material bands 3a at the cutting portion 11, magnetic materials 3 having different lengths L1 to Ln are formed as shown in FIG. The width W of the magnetic material 3 is common. Moreover, what is necessary is just to set the length of a magnetic material, and its kind (n) suitably.

  Subsequently, in the stacking step, the cut magnetic materials 3 having a plurality of lengths are stacked (S2). At this time, as shown in FIG. 5, when the magnetic material 3 is formed in an annular shape, the length of the magnetic material 3 serving as the inner periphery is Li, and the length of the magnetic material 3 serving as the outer periphery is Lo. Lamination is performed in a state where the length (Lo) of the magnetic material 3 serving as the outer periphery is longer than a value obtained by adding π times the stacking thickness (Ts) to the length (Li) of the magnetic material 3 serving as the inner periphery. A body 20 is formed.

  This shows an example in which the U-shaped iron core piece 2 is combined to form the annular iron core 1 in this embodiment, but the outer peripheral length is laminated to the inner peripheral length in the state where the annular iron core 1 is formed. In order to make it longer than the value obtained by adding 2π times the thickness (Ts), in the state of the U-shaped iron core piece 2, the length (Lo) of the magnetic material 3 that is the outer periphery is the magnetic material that is the inner periphery. This is because it should be longer than a value obtained by adding π times the stacking thickness (Ts) to the length (Li) of 3.

  Therefore, the laminated body 20 is formed in a trapezoidal shape that is inclined from the magnetic material 3 side that is the inner periphery toward the magnetic material 3 side that is the outer periphery. Although the length of each magnetic material 3 may be different as in the present embodiment, since the magnetic material 3 is very thin as described above, the same length as described in the third embodiment to be described later. The laminated body 20 may be formed by laminating laminated blocks 20a (see FIG. 10A) in which the magnetic material 3 is laminated with a predetermined thickness.

  Subsequently, in the molding step, the laminate 20 is molded into a predetermined shape, in this embodiment, a U-shape (S3). Specifically, as shown in FIG. 6 (a), in the state where the center of the laminate 20 is held down and held by the jig 21, the both ends of the laminate 20 are lifted as shown in FIG. 6 (b). Molded into a U-shape. In FIG. 6B and each drawing described later, the fact that a gap is provided between the layers of the magnetic material 3 in the corner portion is schematically illustrated by changing the line spacing between the inner peripheral side and the outer peripheral side. Show.

  At this time, it is assumed that the end of the laminated body 20 is slightly shifted. However, as shown in FIG. By hitting, the end of the laminate 20 can be easily leveled. As described above, since the length of the magnetic material 3 serving as the outer periphery is different from the length of the magnetic material 3 serving as the inner periphery as described above, the magnetic material 3 is formed at the corner portion by leveling the end portions of the stacked body 20. A gap is formed between the layers.

  In addition, although not shown, by fastening the straight portion with, for example, a band or the like with the end portion leveled, more specifically, the end portion side, the boundary between the straight portion and the corner portion, and the like are fastened. As a result, the laminated body 20 can be prevented from being scattered, and workability can be improved in the subsequent steps.

  Subsequently, in the fixing step, the molded laminated body 20, that is, the magnetic material 3 is fixed (S4). In this fixing step, for example, as shown in FIG. 7A, the laminated body 20 is fixed by applying an adhesive 30 to the laminated end faces of the magnetic material 3, that is, the front and back surfaces of the iron core 1. Alternatively, as shown in FIG. 7B, the laminate 20 is fixed by impregnating the laminate 31 with the resin 31. The adhesive 30 and the resin 31 may be used for fixing.

  At this time, in this embodiment, the resin 31 is impregnated between the layers of the laminated body 20 only and fixed. Here, “only at the straight portion” means a state where the resin 31 is not impregnated into the corner as much as possible, and the resin 31 is slightly impregnated on the corner portion side from the boundary between the straight portion and the corner. Is acceptable. In other words, “only in the straight portion” means that the resin 31 is not impregnated in the entire corner portion.

  On the other hand, when a material having higher flexibility than the resin 31 is used as the adhesive 30, more strictly, a material having flexibility that can accept the dimensional change when the magnetic material 3 is thermally expanded, It is good also as a state which covers the lamination | stacking end surface of the material 3 with the adhesive agent 30 including a corner part.

  Subsequently, in the polishing step, the surface of the end portion of the laminated body 20, which is fixed, that is, the portion that becomes the facing surface 2a of the core piece 2 is polished horizontally (S5). As a result, as shown in FIG. 8, an iron core piece 2 is formed which is formed in a substantially U shape as a whole and whose opposing surface 2 a is horizontally polished.

  And the iron core 1 shown in FIG. 1 is manufactured by combining the two iron core pieces 2 with each other. In addition, although illustration is abbreviate | omitted in FIG. 1, when the iron core 1 is actually used, it will be fastened from the outer peripheral side by fastening members, such as a band, and the iron core piece 2 will not come apart. Yes.

According to the embodiment described above, the following effects can be obtained.
The iron core 1 is formed in a ring shape having a corner portion and a straight portion by laminating thin plate-like magnetic materials 3, and the length of the outer periphery in the annular state is equal to the length of the inner periphery of the magnetic material 3 in the straight portion. It is characterized by being longer than a value obtained by adding 2π times the stacking thickness (Ts).

  With such a configuration, in the iron core 1, a gap is formed between the layers of the magnetic material 3 at the corner portion due to a difference in length between the magnetic material 3 on the outer peripheral side and the magnetic material 3 on the inner peripheral side. . And even if the inner circumference is higher than the outer circumference and the thermal expansion is larger than the outer circumference due to the gap, as described above, the thermal expansion is caused by the magnetic material 3 on the outer circumference side and the magnetic material 3 on the inner circumference side. Even if the degree of dimensional change due to is different, the dimensional change of the magnetic material 3 can be absorbed by the gap formed in the corner portion, and the pressure generated in the stacking direction at the corner portion can be reduced. Therefore, an increase in iron loss and excitation current at the corner can be suppressed, and stable characteristics can be obtained.

  The iron core 1 is formed in an annular shape by combining two U-shaped iron core pieces 2 with each other. In this case, since the gap is formed in the corner portion as described above, even if a force pushing the U-shaped end surface, that is, the opposing surface 2a is generated, the corner portion is appropriately deformed, so that the corner portion Generation of force in the stacking direction is reduced.

Further, when the corner portion is appropriately deformed, the force applied to the facing surface 2a becomes uniform on the inner peripheral side and the outer peripheral side, and the expansion of the outer peripheral side gap and the accompanying fringing of the magnetic flux can be reduced. An increase in excitation current can be further suppressed.
The magnetic material 3 is formed by forming an amorphous material or a nanocrystal material into a thin plate shape. Thereby, the characteristic in a high frequency can be improved.

  The magnetic material 3 is fixed by applying an adhesive 30 to an end face of the magnetic material 3. Thereby, it is possible to prevent the magnetic material 3 from being scattered and to ensure the dimensional accuracy of the iron core 1. At this time, by using a flexible material as in the embodiment, the deformation of the magnetic material 3 in the corner portion is allowed, and the pressure in the corner portion can be reduced as described above. Can be suppressed.

The magnetic material 3 is fixed by being impregnated with a resin 31 between the layers. Thereby, the magnetic material 3 can be firmly fixed and the outer shape can be prevented from being unnecessarily deformed.
The resin 31 is impregnated between the layers of the magnetic material 3 in the linear portion. That is, the resin 31 is not impregnated in the corner portion. Thereby, the deformation of the magnetic material 3 in the corner portion is allowed, and the pressure in the corner portion can be reduced as described above, and an increase in iron loss and excitation current can be suppressed.

  In addition, the step of cutting the magnetic material 3 with a plurality of lengths, and the length of the outer periphery in the state in which the plurality of cut magnetic materials 3 are formed in an annular shape are the length of the inner periphery, and the magnetic material in the linear portion Including a step of laminating in a state longer than a value obtained by adding 2π times the lamination thickness (Ts) of 3, a step of forming the laminated magnetic material, and a step of fixing the formed magnetic material 3 Also by the manufacturing method of the iron core 1, an increase in iron loss and exciting current at the corner can be suppressed, and stable characteristics can be obtained.

  Further, the cutting portion 11 for cutting the magnetic material 3 into a plurality of lengths, and the length of the outer periphery in a state where the plurality of cut magnetic materials 3 are formed in an annular shape are the length of the inner periphery at the straight portion. The laminated part 12 is laminated so as to be longer than the value obtained by adding 2π times the laminated thickness (Ts) of the magnetic material 3, the molded part 13 for molding the laminated magnetic material 3, and the molded magnetic material 3. Also by the manufacturing apparatus 10 of the iron core 1 provided with the adhering fixing part 14, it is possible to suppress an increase in iron loss and exciting current in the corner part, and to obtain stable characteristics.

(Second Embodiment)
Hereinafter, a second embodiment will be described with reference to FIG. In the second embodiment, the shape of the gap is different from that of the first embodiment.

  As shown in FIG. 9A, the iron core 40 of the present embodiment is configured by combining two iron core pieces 2, while the gap length on the inner peripheral side (between the opposing surfaces 2 a of each iron core piece 2 ( A gap in which Gi) is larger than the outer peripheral gap length (Go) is formed. That is, the iron core 40 is provided with a gap that expands from the outer periphery toward the inner periphery on the opposing surface 2 a of the two iron core pieces 2.

At this time, the gap length (Gi) on the inner circumferential side and the gap length (Go) on the outer circumferential side are appropriately set in consideration of the state during actual operation, that is, considering deformation due to thermal expansion. Has been.
Thereby, even if the dimensional change of the magnetic material 3 on the inner peripheral side increases as the thermal expansion on the inner peripheral side increases as described above, the gap length is substantially uniform during actual operation. Deterioration of characteristics can be reduced.

  Further, as shown in FIG. 9B, such a gap is relatively formed while forming a gap between the layers of the magnetic material 3 in the corner portion by using an inclined leveling jig 23 in the molding process. It can be formed easily. Steps other than the molding step are common to the first embodiment.

(Third embodiment)
The third embodiment will be described below with reference to FIG. In the third embodiment, the structure of the iron core is different from that of the first embodiment.

  As shown to Fig.10 (a), the iron core 50 of this embodiment has a structure where the stepped cutting part 50a was provided in one cyclic | annular place. That is, unlike the iron core 1, the iron core 50 is not a combination of the iron core pieces 2, but is formed in an annular shape using a single laminate 20 as shown in FIG.

  The stacked body 20 is formed by stacking a plurality of stacked blocks 20a. This laminated block 20a is obtained by laminating magnetic materials 3 having the same length to a predetermined thickness. At this time, in the laminated block 20a, the length (Lo) of the laminated block 20a serving as the outer periphery is greater than the value obtained by adding 2π times the laminated thickness (Ts) to the length (Li) of the laminated block 20a serving as the inner periphery. They are stacked in a long state.

  Subsequently, in the laminated body 20, first, the molding region R2 is formed while forming a gap in the corner portion in the molding step, and then the molding region R2 is fixed in the fixing step. Thereby, the laminated body 20 becomes a vertically long substantially U shape in a state where a gap is formed between the layers of the magnetic material 3 at the corner portion.

  Then, after passing a coil (not shown) through, for example, a longitudinal straight portion of the vertically long substantially U-shaped laminate 20, a portion that is not fixed is folded, whereby the iron core 50 having the shape shown in FIG. 10A is obtained. . At this time, the folded end portion of the folded portion is fixed by, for example, the adhesive 30. In addition, it is good also as a structure using the fastening member which fastens the iron core 50 from the outer peripheral side.

  The iron core 50 formed in this way is formed into an annular shape in which the thin plate-like magnetic material 3 is laminated and has a corner portion and a straight portion, and the outer peripheral length in the annular state is linear to the inner peripheral length. Is longer than the value obtained by adding 2π times the laminated thickness of the magnetic material 3 at the portion, so that the difference in length between the magnetic material 3 on the outer peripheral side and the magnetic material 3 on the inner peripheral side causes A gap is formed between the layers.

  Thereby, since the iron core 50 can absorb the dimensional change of the magnetic material 3 by the gap formed in the corner portion, the pressure generated in the stacking direction in the corner portion can be reduced. Similarly to the iron core 1 of the first embodiment, An increase in iron loss and excitation current can be suppressed, and stable characteristics can be obtained.

Moreover, since the laminated block 20a is laminated, the cutting part 50a side can be easily folded.
In addition, the lamination | stacking aspect shown in FIG.10 (b) is an example, and it is not provided with the stepped cutting part 50a, but even if it provides the cutting part 50a of the positional relationship which is mutually alternate between the lamination | stacking blocks 20a. Good.

(Other embodiments)
The present invention is not limited to those shown in the above-described embodiments, and various modifications or combinations are possible without departing from the scope of the present invention.
In the embodiment, an iron-based amorphous material or a nanocrystal material is exemplified as the magnetic material 3, but a silicon steel strip may be used.

The laminated portion 12, the forming portion 13, the fixing portion 14, or the polishing portion 15 exemplified in the embodiment may be a device that automatically performs a process, or an operator manually implements using a jig. It may be a thing or both may cooperate.
In FIG. 5 of the first embodiment, the length (Lo) of the magnetic material 3 on the outermost side is the length (Li) of the magnetic material 3 on the inner periphery plus π times the stacking thickness (Ts). However, this does not specify only the magnetic material 3 on the outermost periphery side, and the length of the magnetic body 3 located on the inner periphery side is longer than Li + π · Ts. It may be longer. Also, FIG. 10 of the third embodiment does not specify only the length (Lo) of the magnetic material 3 on the outermost side, but the length of the magnetic body 3 located on the inner side is Li + 2π · It may be longer than Ts.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 1, 40 and 50 are iron cores, 2 are iron core pieces, 2a is a facing surface, 3 is a magnetic material, 10 is a manufacturing apparatus (iron core manufacturing apparatus), 11 is a cutting part, 12 is a laminated part, and 13 is a molding. Part, 14 is a fixing part, 20 is a laminated body, 20a is a laminated block, 30 is an adhesive, and 31 is a resin.

Claims (9)

  A thin plate-like magnetic material is laminated and formed into an annular shape having a corner portion and a straight portion, and the length of the outer circumference in the annular state is 2π of the laminated thickness of the magnetic material in the straight portion in the length of the inner circumference. An iron core characterized by being longer than the doubled value.   The iron core according to claim 1, wherein the iron core is formed in an annular shape by combining two U-shaped core pieces.   The iron core according to claim 2, wherein a gap that expands from the outer periphery toward the inner periphery is provided on opposing surfaces of the two iron core pieces.   The iron core according to any one of claims 1 to 3, wherein the magnetic material is an amorphous material or a nanocrystal material formed into a thin plate shape.   The iron core according to any one of claims 1 to 4, wherein the magnetic material is fixed by applying an adhesive to an end face of the laminated magnetic material.   6. The iron core according to claim 1, wherein the magnetic material is fixed by impregnating a resin between the layers.   The iron core according to claim 6, wherein the resin is impregnated between layers of the magnetic material in the linear portion. A method for manufacturing an iron core, in which a thin plate-like magnetic material is laminated and an annular iron core having a corner portion and a straight portion is manufactured,
Cutting the magnetic material into a plurality of lengths;
The length of the outer periphery in the state in which the plurality of cut lengths of the magnetic material are formed in an annular shape is greater than the value obtained by adding 2π times the lamination thickness of the magnetic material in the linear portion to the length of the inner periphery. A step of laminating in a long state;
Forming the laminated magnetic material;
Fixing the molded magnetic material; and
The manufacturing method of the iron core characterized by including. An apparatus for manufacturing an iron core that laminates thin plate-like magnetic materials and produces an annular iron core having a corner portion and a straight portion,
A cutting part for cutting the magnetic material into a plurality of lengths;
The length of the outer periphery in the state in which the plurality of cut lengths of the magnetic material are formed in an annular shape is greater than the value obtained by adding 2π times the lamination thickness of the magnetic material in the linear portion to the length of the inner periphery. A laminating portion for laminating in a long state;
A molding part for molding the laminated magnetic material;
An adhering portion for adhering the molded magnetic material;
An iron core manufacturing apparatus comprising:

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