Iron core, stator and rotating motor

Abstract

A core used in an axial gap type rotating electric machine, the core being annular and having a plurality of core sheets dividing the core in the circumferential direction, the core sheets comprising: a yoke; and a tooth portion integrally formed with the yoke and protruding axially from the yoke, the yoke comprising: a plurality of protrusions arranged on a side surface connected to the yoke of an adjacent core sheet; and a plurality of recesses corresponding to the protrusions and arranged on another side surface connected to the yoke of another adjacent core sheet, the spacing between the protrusions being less than or equal to 80% of the length of the side surface of the yoke determined by the straight-line distance between the outer periphery and the inner periphery of the yoke.

Description

Technical Field

[0001] The invention relates to an iron core, a stator and a rotating electric machine.

[0002] This application claims priority based on Japanese Patent Application No. 2018-228584 filed on December 5, 2018, and all the contents described in the above Japanese application are cited. Background Art

[0003] Patent document 1 discloses an axial gap type rotating electric machine in which a rotor and a stator are arranged opposite to each other in the axial direction. The stator used in this rotating electric machine has: an annular yoke; an iron core having a plurality of teeth protruding from the yoke in the axial direction; and a coil arranged on each tooth. Patent document 1 describes that the iron core is divided in the circumferential direction to form a plurality of iron core sheets, and the iron core sheets are formed by a powder magnetic core in which the yoke and the teeth are integrally formed.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2017-229191 Summary of the invention

[0005] The iron core of the present invention is used in an axial gap type rotating electrical machine.

[0006] The core is annular and has a plurality of core pieces divided in the circumferential direction.

[0007] The core sheet has:

[0008] a yoke; and

[0009] a tooth portion, which is integrally formed with the yoke portion and protrudes from the yoke portion in the axial direction,

[0010] The yoke comprises:

[0011] a plurality of protrusions provided on a side surface connected to a yoke portion of an adjacent core sheet; and

[0012] A plurality of recessed portions, which correspond to the convex portions and are provided on the other side surface connected to the yoke portion of another adjacent core sheet,

[0013] The interval between the protrusions is less than or equal to 80% of the length of the side surface of the yoke determined by the straight-line distance between the outer periphery and the inner periphery of the yoke.

[0014] The stator of the present invention is a stator of an axial gap type rotating electric machine, and has:

[0015] The iron core of the present invention; and

[0016] The coil is arranged on each of the teeth of the core sheet constituting the core.

[0017] The rotary electric machine of the present invention comprises a rotor and a stator, and is an axial gap type rotary electric machine in which the rotor and the stator are arranged to face each other in the axial direction.

[0018] In the rotating electrical machine,

[0019] The stator is the stator of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic perspective view of the iron core involved in the embodiment.

[0021] Figure 2 It is a schematic plan view of the core according to the embodiment.

[0022] Figure 3 is along Figure 2 A schematic cross-sectional view of the iron core of the III-III line.

[0023] Figure 4 It is a schematic perspective view of an iron core sheet.

[0024] Figure 5 It is a schematic top view of the core piece.

[0025] Figure 6 It is a schematic cross-sectional view showing an example of a mold for molding an iron core sheet.

[0026] Figure 7 It is a schematic top view of the die.

[0027] Figure 8 It is an enlarged top view of the main part of the die.

[0028] Fig. 9 It is a schematic side view of an iron core having a plate-like member.

[0029] Fig.10 It is a schematic top view of an iron core having an annular member.

[0030] Fig.11 It is a schematic perspective view of a stator according to the embodiment.

[0031] Fig.12 It is a schematic cross-sectional view of a rotating electrical machine according to the embodiment. DETAILED DESCRIPTION

[0032] [Problems to be Solved by the Invention]

[0033] In order to improve the productivity of the axial gap type rotating electrical machine, it is desired to improve the assemblability of the core.

[0034] In the case where the core is formed by a plurality of core sheets, the plurality of core sheets need to be combined into a ring shape so that the side surfaces of the yokes of adjacent core sheets are butted against each other for connection. As in Patent Document 1, if the side surfaces of the yokes of each core sheet are formed into a straight line along the radial direction, it is difficult to position the yokes of adjacent core sheets relative to each other. For example, sometimes when a plurality of core sheets are combined into a ring shape, adjacent core sheets are offset in the radial direction.

[0035] One object of the present invention is to provide an iron core having excellent assemblability. Another object of the present invention is to provide a stator having the iron core. Another object of the present invention is to provide a rotating electric machine having the stator.

[0036] [Effects of the Invention]

[0037] The iron core of the present invention is excellent in assemblability. The stator of the present invention is excellent in assemblability of the iron core. The rotary electric machine of the present invention has high productivity.

[0038] [Description of Embodiments of the Invention]

[0039] The inventors of the present invention considered providing a convex portion on one side of the yoke of the core sheet and providing a concave portion corresponding to the convex portion on the other side, thereby positioning the yokes of adjacent core sheets relative to each other through the engagement of the convex portion and the concave portion. In the process, the inventors of the present invention conducted a concentrated study and found that when a convex portion is provided on the side of the yoke, when the core sheet composed of a pressed powder core is formed by a mold, in the die for forming the peripheral surface of the yoke, the stress acting on the portion forming the side of the yoke becomes larger. If excessive stress acts on the die, the die may be damaged. Therefore, it is important to design the convex portion provided on the side of the yoke so that the load on the die can be reduced as much as possible. As a result of the inventors' concentrated study, it was found that a plurality of convex portions are provided on the side of the yoke, and the intervals between the convex portions are set to be less than or equal to 80% of the length of the side of the yoke, thereby reducing the stress acting on the die as described later.

[0040] The present invention has been proposed based on the above findings. First, embodiments of the present invention will be described below.

[0041] (1) An iron core according to an embodiment of the present invention is used in an axial gap type rotating electrical machine.

[0042] The core is annular and has a plurality of core sheets which divide the core in the circumferential direction.

[0043] The core sheet has:

[0044] a yoke; and

[0045] a tooth portion, which is integrally formed with the yoke portion and protrudes from the yoke portion in the axial direction,

[0046] The yoke comprises:

[0047] a plurality of protrusions provided on a side surface connected to a yoke portion of an adjacent core sheet; and

[0048] A plurality of recessed portions, which correspond to the convex portions and are provided on the other side surface connected to the yoke portion of another adjacent core sheet,

[0049] The interval between the protrusions is less than or equal to 80% of the length of the side surface of the yoke determined by the straight-line distance between the outer periphery and the inner periphery of the yoke.

[0050] The iron core of the present invention is easy to align adjacent iron core sheets and has excellent assembly properties. The reason is that a yoke of an iron core sheet has a plurality of protrusions on one side and a plurality of recesses corresponding to the protrusions on the other side, thereby enabling the yokes of adjacent iron core sheets to be positioned relative to each other by fitting the protrusions and recesses. Therefore, according to the iron core of the present invention, when a plurality of iron core sheets are combined into a ring shape, radial displacement of adjacent iron core sheets can be suppressed.

[0051] In the case where the core sheet is a powder core, the core sheet composed of the powder core is obtained by compression molding a collection of multiple soft magnetic particles, namely soft magnetic powder. When the core sheet is molded by a mold, the spacing between the protrusions on the side of the yoke is less than or equal to 80% of the length of the side of the yoke, thereby reducing the stress acting on the side of the die that molds the side of the yoke. As a result, it is also possible to expect the effect of reducing the load on the die and suppressing damage to the die. The significance of the spacing between the protrusions and the reason why the stress acting on the die can be reduced will be described later.

[0052] (2) As one form of the above-mentioned iron core,

[0053] For example: when the yoke is viewed from above from the protruding side of the tooth portion, a middle line between the opposite side surfaces of the tooth portion and the tooth portion of another adjacent iron core sheet is set as a reference line, and a distance from the recessed portion to the root of the tooth portion is greater than or equal to 20% of a distance from the reference line to the root of the tooth portion.

[0054] The above method is that the distance from the recess to the root of the tooth is greater than or equal to 20% of the distance from the reference line to the root of the tooth, so that in the core sheet, the interval between the recess in the surface on the protruding side of the tooth of the yoke and the root of the tooth can be ensured to a certain extent. Therefore, when the core sheet is a pressed powder magnetic core, the strength of the punch that is formed by the die when the core sheet is formed can be suppressed due to the reduction in the thickness of the punch that forms the surface on the protruding side of the tooth of the yoke.

[0055] (3) As one embodiment of the above-mentioned iron core,

[0056] For example, the size of the protrusion is greater than or equal to 1 mm and less than or equal to 10 mm.

[0057] In the above method, the size of the protrusion is greater than or equal to 1 mm, so that the yokes of adjacent core sheets can be easily positioned. In the case where the core sheet is a pressed powder magnetic core, the size of the protrusion is less than or equal to 10 mm, so that it is easy to form. The significance of the size of the protrusion will be described later.

[0058] (4) As one embodiment of the above-mentioned iron core,

[0059] For example, the minimum curvature radius of the convex portion and the concave portion when the yoke portion is viewed from above from the convex side of the tooth portion is greater than or equal to 1.0 mm.

[0060] The above method can suppress the damage of the die when the core sheet is a powder core. The reason is that the minimum radius of curvature of the convex part and the concave part is greater than or equal to 1.0 mm, thereby relieving the stress concentration of the die that forms the side of the yoke when the core sheet is formed by the die.

[0061] (5) As one embodiment of the above-mentioned iron core,

[0062] For example, the adjacent convex portions are symmetrical with respect to a center line between the convex portions.

[0063] The above method can more effectively suppress damage to the die when the core sheet is a powder core. The reason is that the adjacent protrusions are symmetrical, which can effectively reduce the stress acting on the die when the core sheet is molded by the die.

[0064] (6) As one embodiment of the above-mentioned iron core,

[0065] For example, the thickness of the yoke is greater than or equal to 1.0 mm and less than or equal to 10 mm.

[0066] In the above-mentioned iron core, sometimes when a plurality of iron core sheets are combined into an annular state, an annular component is fitted into the outer peripheral surface of the yoke to be fixed, thereby fastening the plurality of iron core sheets. If the thickness of the yoke is greater than or equal to 1.0 mm, it is easy to fix the annular component and to ensure the fastening force. If the yoke is too thick, the load on the die increases, so the thickness of the yoke is set to be less than or equal to 10 mm.

[0067] (7) As one embodiment of the above-mentioned iron core,

[0068] For example: the core piece is formed by a pressed powder magnetic core,

[0069] The powder magnetic core is composed of a plurality of coated soft magnetic particles having an insulating coating on the surface of the soft magnetic particles.

[0070] The soft magnetic particles are iron-based particles composed of at least one of pure iron and an iron-based alloy.

[0071] The iron-based alloy is at least one selected from the group consisting of Fe—Si-based alloys, Fe—Al-based alloys, Fe—Cr—Al-based alloys, and Fe—Cr—Si-based alloys.

[0072] Pure iron or the above-mentioned iron-based alloy is a relatively soft material. Therefore, the soft magnetic particles constituting the powdered magnetic core are iron-based particles composed of pure iron or the above-mentioned iron-based alloy, so that the soft magnetic particles are easily deformed when the powdered magnetic core is formed. Thus, the above-mentioned method obtains a powdered magnetic core with high density and high dimensional accuracy. By making the powdered magnetic core high-density, the mechanical strength and magnetic properties of the iron core sheet can be improved. In addition, there is an insulating coating on the surface of the soft magnetic particles, so that the electrical insulation between the soft magnetic particles can be improved. Therefore, the iron loss of the iron core sheet caused by eddy current loss can be reduced.

[0073] (8) As one embodiment of the iron core described in (7),

[0074] For example: the insulating coating comprises a phosphate coating.

[0075] The phosphate coating has high adhesion to the iron-based particles and excellent deformability. Therefore, the insulating coating includes the phosphate coating, which makes it easy to follow the deformation of the iron-based particles when the powder magnetic core is formed. Therefore, the insulating coating of the above method is not easy to be damaged, and the iron loss of the iron core 10 can be reduced.

[0076] (9) As one embodiment of the iron core described in (7) or (8),

[0077] For example, the relative density of the powder magnetic core is greater than or equal to 90%.

[0078] The relative density of the powder magnetic core is 90% or more, so the density of the powder magnetic core is high. The above-mentioned aspect can improve the mechanical strength and magnetic properties of the core piece by increasing the density of the powder magnetic core.

[0079] (10) As one embodiment of the above-mentioned iron core,

[0080] For example, a ring-shaped member is provided, and the ring-shaped member is fitted on the outer peripheral surface of the yoke portion of the plurality of core sheets.

[0081] The annular member fixes the plurality of core sheets by a contraction force in the inner diameter direction thereof.

[0082] In the iron core, there is an annular component embedded in the outer peripheral surface of the yoke, thereby integrating a plurality of iron core sheets combined into an annular shape. In addition, the outer periphery of the yoke can be tightened by the contraction force in the inner diameter direction of the annular component, and the plurality of iron core sheets can be firmly tightened.

[0083] (11) As one embodiment of the above-mentioned iron core,

[0084] For example, the side surfaces of the yokes of adjacent core sheets are bonded to each other, or

[0085] A plate-like member is provided. The plate-like member is arranged on the side of the yoke of the adjacent core sheet opposite to the side on which the teeth protrude. The surface of the yoke on the opposite side is bonded to the plate-like member.

[0086] The side surfaces of the yokes of adjacent core sheets are bonded to each other, or the surface of the yoke opposite to the protruding side of the teeth is bonded to the plate-like member, whereby the plurality of core sheets can be integrated in a state of being combined in a ring shape.

[0087] (12) As one embodiment of the above-mentioned iron core,

[0088] For example, a difference between a position of an end surface of a highest tooth portion and a position of an end surface of a lowest tooth portion among the teeth portions of the plurality of core sheets is less than or equal to 0.15 mm.

[0089] When the surface of the yoke opposite to the protruding side of the tooth is placed on a plane, the difference between the position of the end face of the highest tooth and the position of the end face of the lowest tooth is less than or equal to 0.15 mm, thereby reducing the fluctuation in the height of each end face of the tooth. In the case of using the above-mentioned iron core to form a rotating electric machine, each end face of the tooth is arranged to be opposite to the magnet of the rotor. The fluctuation in the height of each end face of the tooth is small, thereby reducing the fluctuation in the interval between each end face of the tooth and the rotor in the rotating electric machine. As a result, the cogging effect can be reduced, and the degradation of the characteristics of the rotating electric machine can be suppressed.

[0090] (13) As one embodiment of the above-mentioned iron core,

[0091] For example, when the plurality of core sheets are combined in a ring shape, the roundness of the outer peripheral surface of the yoke is less than or equal to 0.1 mm.

[0092] The roundness of the outer peripheral surface of the yoke is less than or equal to 0.1 mm, whereby the dimensional accuracy of the core is high.

[0093] (14) As one embodiment of the above-mentioned iron core,

[0094] For example: the flatness of the end face of the tooth portion is less than or equal to 0.2 mm.

[0095] The flatness of the end face of the tooth portion is equal to or less than 0.2 mm, so that the end face of the tooth portion and the rotor can be closely facing each other in the rotating electrical machine, thereby suppressing the degradation of the characteristics of the rotating electrical machine.

[0096] (15) A stator according to an embodiment of the present invention is a stator of an axial gap type rotating electrical machine, and the stator has:

[0097] The iron core according to any one of (1) to (14) above; and

[0098] The coil is arranged on each of the teeth of the core sheet constituting the core.

[0099] The stator of the present invention has excellent assemblability of the core. This is because the core can easily align adjacent core pieces and has excellent assemblability.

[0100] (16) A rotating electrical machine according to an embodiment of the present invention includes a rotor and a stator, and is an axial gap type rotating electrical machine in which the rotor and the stator are arranged to face each other in the axial direction.

[0101] In this rotating electrical machine, the stator is the stator described in (15) above.

[0102] The rotary electric machine of the present invention has high productivity because the stator has excellent assemblability of the core.

[0103] [Details of the embodiments of the present invention]

[0104] Hereinafter, specific examples of the core, stator and rotating electrical machine involved in the embodiments of the present invention will be described with reference to the accompanying drawings. The same reference numerals in the figures represent the same names. In addition, the present invention is not limited to these examples, but is shown by the claims, including all changes within the meaning and scope equivalent to the claims.

[0105] <Iron core>

[0106] Reference Figures 1 to 10 The iron core 1 and the iron core sheet 10 constituting the iron core 1 according to the embodiment will be described. The iron core 1 is used in an axial gap type rotating electric machine. More specifically, the iron core 1 can be used as an iron core of a stator. Figure 1 , Figure 2 As shown in FIG. 1 , the core 1 is annular and has a plurality of core sheets 10 that divide the core 1 in the circumferential direction. That is, the core 1 is formed by combining a plurality of core sheets 10 in an annular shape. In this example, the number of core sheets 10 is 6. The core sheet 10 has a yoke 11 and a tooth 12 that protrudes in the axial direction from the yoke 11 (see also FIG. 1 ). Figure 4 , Figure 5). In the following description, when the core 1 and the core sheet 10 are described, the protruding side of the teeth 12 is set as the top, and the opposite side thereof is set as the bottom.

[0107] In this example, if Figure 1 , Figure 2 As shown, the core 1 is in the shape of a ring. Specifically, in the core 1, the yoke 11 is in the shape of a ring plate, and a plurality of teeth 12 are arranged at equal intervals in the circumferential direction. In this example, the number of teeth 12 is 12. In this example, the core 1 is divided into 6 equal parts, and has 6 core sheets 10, specifically, core sheets 10a to 10f. The shapes of the core sheets 10a to 10f are the same. The core 1 is formed by combining the 6 core sheets 10a to 10f into a ring shape, so that the side surfaces 20 and 30 (refer to Figure 4 , Figure 5 ) are connected to each other by butting. The number of divisions of the core 1, in other words, the number of core pieces 10 can be appropriately selected. In addition, the number of teeth 12 in the core 1 can also be appropriately set.

[0108] (Iron chip)

[0109] Iron chip 10 Figure 4 , Figure 5 As shown, the core sheet 10 has a yoke 11 and a tooth 12. The core sheet 10 is formed by a powder core. The yoke 11 and the tooth 12 are integrally formed.

[0110] (yoke part)

[0111] The yoke 11 is a fan-shaped portion constituting the core sheet 10. The yoke 11 has a fan-shaped plane, and a tooth portion 12 protrudes from one plane. That is, one plane refers to the upper surface. The yoke 11 has an arc-shaped inner peripheral surface and an outer peripheral surface and side surfaces 20 and 30. The inner peripheral surface and the outer peripheral surface are formed in a concentric arc shape.

[0112] (Tooth)

[0113] The tooth portion 12 is formed integrally with the yoke portion 11, and is a portion protruding axially from a plane of the yoke portion 11, that is, the upper surface. The axial direction refers to a direction orthogonal to the circumferential and radial directions of the core 1, and specifically, refers to a vertical direction relative to the upper surface of the yoke portion 11. The tooth portion 12 is a columnar body, and as a columnar body, for example, a prism, a cylinder, an elliptical cylinder, etc. are cited. Among the prisms, a triangular prism, a trapezoidal cylinder, etc. are cited. In this example, the tooth portion 12 is a triangular prism, and the shape of the end face 41 of the tooth portion 12 is a triangle, more specifically, an isosceles triangle. The tooth portion 12 may also be a trapezoidal cylinder, and the shape of the end face 41 may also be a trapezoid, etc. In addition, the "triangular shape" and "trapezoidal shape" may not be a triangle or a trapezoid in the strict sense of geometry, and may also include shapes with chamfers at the corners, etc., including a range that can be essentially regarded as a triangle and a trapezoid.

[0114] The number of teeth 12 in the core sheet 10 may be one or more. In this example, there are two teeth 12 (12a, 12b). The teeth 12 located on the side 20 of the yoke 11 are 12a, and the teeth 12 located on the side 30 are 12b.

[0115] One of the characteristics of the core 1 is that Figure 4 , Figure 5 As shown, a plurality of protrusions 21, 22 are provided on one side 20 of the yoke 11 of the core piece 10, and a plurality of recesses 31, 32 corresponding to the protrusions 21, 22 are provided on the other side 30. Another characteristic point of the core 1 is that the interval between the protrusions 21, 22 is less than or equal to 80% of the length of the side 20 of the yoke 11.

[0116] 〈Protruding part and concave part〉

[0117] The yoke 11 includes a plurality of convex portions 21, 22 provided on one side surface 20 and a plurality of concave portions 31, 32 provided on the other side surface 30. The convex portions 21, 22 of the side surface 20 and the concave portions 31, 32 of the side surface 30 are formed into shapes corresponding to each other. There is a concave portion 23 between the convex portions 21, 22, and there is a convex portion 33 between the concave portions 31, 32. In this example, the convex portions 21, 22 and the concave portions 31, 32 are respectively in the same arc shape and have the same size. Here, as shown in FIG. Figure 5As shown, one side surface 20 of the yoke 11 in the core sheet 10a is connected to the other side surface 30 of the yoke 11 in the adjacent core sheet 10b. The other side surface 30 of the yoke 11 in the core sheet 10a is connected to one side surface 20 of the yoke 11 in the adjacent core sheet 10f. Therefore, the protrusions 21, 22 provided on the side surface 20 of the yoke 11 in the core sheet 10a and the recesses 31, 32 provided on the side surface 30 of the yoke 11 in the adjacent core sheet 10b fit together. The recesses 31, 32 provided on the side surface 30 of the yoke 11 in the core sheet 10a and the protrusions 21, 22 provided on the side surface 20 of the yoke 11 in the adjacent core sheet 10f fit together. By fitting the protrusions 21, 22 and the recesses 31, 32, the yokes 11 of the core sheet 10a and the adjacent core sheets 10b, 10f can be positioned relative to each other. Therefore, when the plurality of core sheets 10 are combined in a ring shape, it is possible to suppress radial displacement of the adjacent core sheets 10 .

[0118] In this example, the number of the convex parts 21, 22 and the number of the concave parts 31, 32 are 2. The number of the convex parts 21, 22 and the concave parts 31, 32 can be changed appropriately, and can also be greater than or equal to 3. In addition, the shape of the convex parts 21, 22 and the concave parts 31, 32 can be changed appropriately, for example, it can also be a rectangular shape, a triangular shape, etc. In the case of this example, the shape of each convex part 21, 22 is the same shape, but the shape of each convex part 21, 22 can also be different.

[0119] 〈Interval between convex parts〉

[0120] The interval between the protrusions 21 and 22 is less than or equal to 80% of the length of the side surface 20 of the yoke 11. The interval between the protrusions 21 and 22 is defined as follows. Figure 5 As shown, a middle line L passing through the middle point between the tooth portion 12a of the core piece 10a and the tooth portion 12b of an adjacent core piece 10b is taken. A Specifically, a line passing through the middle point between the mutually opposing side surfaces of the tooth portion 12a of the core sheet 10a and the tooth portion 12b of the core sheet 10b is defined as the middle line L. A . Middle line L A is a straight line along the radial direction of the annular core 1. Next, draw A A straight line L1 is drawn parallel to the middle line L and passes through the vertices of the convex portions 21 and 22. A A straight line L2 is parallel to the concave portion 23 located between the adjacent convex portions 21 and 22 and passes through the vertex of the concave portion 23. Two points on the sides of the adjacent convex portions 21 and 22 that intersect the center line La between the straight line L1 and the straight line L2 are respectively defined as points a and b. The distance between the two points ab is defined as the interval between the convex portions 21 and 22. In this example, the center line LA The length of the side surface 20 of the yoke 11 is defined as the linear distance between the outer periphery and the inner periphery of the yoke 11. In other words, the length of the side surface 20 of the yoke 11 refers to the length in the radial direction between the outer periphery and the inner periphery of the yoke 11. In the following, the length of the side surface 20 of the yoke 11 is sometimes referred to as the "yoke side surface length".

[0121] exist Figure 5 In the case where the interval between the protrusions 21 and 22 represented by the distance between a and b is less than or equal to 80% of the length of the side surface of the yoke, as described later, the protrusions 21 and 22 are formed by the die 5 (refer to Figure 6 ) When the core piece 10 is formed, the side surface 52 of the die 50 that forms the side surface 20 of the yoke 11 can be reduced (see Figure 7 , Figure 8 ) stress. For the reason, refer to Figure 8 Described later.

[0122] The ratio of the interval between the protrusions 21 and 22 to the side length of the yoke is further exemplified as less than or equal to 70%, or less than or equal to 50%. The interval between the protrusions 21 and 22 is, for example, less than or equal to 40 mm, or further exemplified as less than or equal to 30 mm. If the interval between the protrusions 21 and 22 is too small, molding becomes difficult, so the lower limit of the interval between the protrusions 21 and 22 is, for example, about 1.0 mm.

[0123] <Adjacent convex parts are symmetrical>

[0124] In this example, the adjacent convex portions 21 and 22 are symmetrical with respect to the center line between the convex portions 21 and 22. Here, the center line between the convex portions 21 and 22 is as shown in FIG. Figure 5 As shown in FIG. 1 , a straight line Lc is set to be perpendicular to the center line La and passes through the midpoint of the line segment ab. When the convex portions 21 and 22 are symmetrical in shape, the side surface 52 (see FIG. 1 ) acting on the die 50 can be effectively reduced. Figure 7 , Figure 8 ) stress.

[0125] <Distance from the concave portion to the root of the tooth>

[0126] In this example, the distance from the recesses 31, 32 to the root of the tooth 12 (12b) is Figure 5 Greater than or equal to from L B The reference line is set to be the middle line between the teeth 12 of adjacent core sheets 10 when the yoke 11 is viewed from the protruding side of the teeth 12, i.e., the upper side. Figure 5As shown in FIG. 1 , a middle line L passing through the middle point between the tooth portion 12b of the core sheet 10a and the tooth portion 12a of another adjacent core sheet 10f is drawn. B Specifically, a line passing through the middle point between the side surfaces of the teeth 12b of the core sheet 10a and the side surfaces of the teeth 12a of the core sheet 10f facing each other is set as the middle line L. B . Middle line L B is a straight line along the radial direction of the annular core 1. Next, draw B A straight line L3 is orthogonal to each other and passes through each vertex of the concave parts 31 and 32. The vertex of the concave parts 31 and 32 on each straight line L3 is set as l, and the intersection point of each straight line L3 and the periphery of the tooth part 12b is set as m. The distance between the two points 1m is set as the distance from the concave parts 31 and 32 to the root of the tooth part 12b. In addition, each straight line L3 and the middle line L B The intersection of the two points nm is set as n. The distance between the two points nm is set as the distance from the reference line to the root of the tooth portion 12b. Here, when drawing the straight line L3, the apex of the recesses 31 and 32 is set as the point farthest from the middle line L in the recesses 31 and 32. B In other words, the apex of the recesses 31 and 32 is set to be the point in the recesses 31 and 32 that is closest to the root of the tooth portion 12b.

[0127] The middle line L B The ratio of the distance from the recesses 31 and 32 to the root of the tooth 12 (12b) relative to the distance from the reference line to the root of the tooth 12 (12b) is greater than or equal to 20%. Figure 5 In the figure, the distance from the reference line to the root of the tooth 12b is represented by the distance between nm. In addition, the distance from the recesses 31, 32 to the root of the tooth 12b is represented by the distance between lm. The ratio (%) of the above distances can be calculated by setting it to [(distance between lm / distance between nm) × 100]. The ratio of the above distances is greater than or equal to 20%, whereby in the core piece 10, the surface on the convex side of the tooth 12 of the yoke 11, that is, the upper surface, can ensure that the spacing between the recesses 31, 32 and the root of the tooth 12 (12b) is within a certain range. In this case, the occurrence of the tooth 12 protruding from the yoke 11 through the mold 5 (refer to Figure 6 ) When the core piece 10 is formed, the strength of the first lower punch 71 is reduced due to the reduction in thickness of the first lower punch 71 that forms the upper surface of the yoke 11.

[0128] The ratio of the distance from the recesses 31 and 32 to the root of the tooth 12 (12b) to the distance from the reference line to the root of the tooth 12 (12b) is further exemplified as being greater than or equal to 30%. The upper limit of the ratio of the distance from the recesses 31 and 32 to the root of the tooth 12 (12b) is not particularly set, and is, for example, 90%. In addition, the distance from the recesses 31 and 32 to the root of the tooth 12 (12b) is, for example, greater than or equal to 1 mm and less than or equal to 9 mm, and further exemplified as being greater than or equal to 2 mm and less than or equal to 8 mm.

[0129] 〈Size of convex part〉

[0130] In this example, the size of the protrusions 21 and 22 is greater than or equal to 1 mm and less than or equal to 10 mm. The size of the protrusions 21 and 22 is defined as follows. In this example, Figure 5 As shown, the distance between a straight line L1 passing through the vertices of the convex portions 21 , 22 and a straight line L2 passing through the vertices of the concave portion 23 located between the adjacent convex portions 21 , 22 is defined as the size of the convex portions 21 , 22 .

[0131] When the size of the protrusions 21 and 22 is greater than or equal to 1 mm, the yokes 11 of adjacent core sheets 10 are easily positioned. The size of the protrusions 21 and 22 is less than or equal to 10 mm, which facilitates molding. The size of the protrusions 21 and 22 is further greater than or equal to 2 mm and less than or equal to 8 mm.

[0132] 〈Minimum radius of curvature of convex and concave parts〉

[0133] In this example, the minimum curvature radius of the convex parts 21, 22 and the concave parts 31, 32 when the yoke part 11 is viewed from the convex side of the tooth part 12, that is, the upper side, is greater than or equal to 1.0 mm. When the shapes of the convex parts 21, 22 and the concave parts 31, 32 are set to have corners with a small curvature radius, the side surfaces 52, 53 (see Figure 7 ) forms a corner. Stress tends to concentrate on the corner with a small curvature radius. When the minimum curvature radius of the convex parts 21, 22 and the concave parts 31, 32 is greater than or equal to 1.0 mm, it is possible to pass through the mold 5 (refer to Figure 6 ) When the iron core sheet 10 is formed, stress concentration on the die 50 is alleviated.

[0134] The minimum radius of curvature of the convex portions 21, 22 and the concave portions 31, 32 is further exemplified as being greater than or equal to 2.0 mm. The upper limit of the minimum radius of curvature of the convex portions 21, 22 and the concave portions 31, 32 is not particularly limited, and is, for example, 20 mm.

[0135] 〈Yoke thickness〉

[0136] The thickness of the yoke 11 is, for example, greater than or equal to 1.0 mm and less than or equal to 10 mm, and further greater than or equal to 2 mm and less than or equal to 8 mm. The thickness of the yoke 11 refers to the dimension of the yoke 11 along the axial direction of the core 1. Figure 3 In the embodiment, the thickness of the yoke 11 is represented by Ty. As described later, when a plurality of core sheets 10 are combined into an annular core 1, an annular member 90 (see FIG. 1 ) is sometimes fitted on the outer peripheral surface of the yoke 11. Fig.10 ) to fix. If the thickness of the yoke 11 is greater than or equal to 1.0 mm, it is easy to fix the annular member 90. If the yoke 11 is too thick, Figure 6 ) The load on the die 50 increases when the core piece 10 is formed. Therefore, the thickness of the yoke 11 is set to be less than or equal to 10 mm.

[0137] 〈Roundness of yoke〉

[0138] In the state where the plurality of core sheets 10 are combined into the annular core 1, it is preferred that the roundness of the outer peripheral surface of the yoke 11 is less than or equal to 0.1 mm. The roundness of the outer peripheral surface of the yoke 11 is less than or equal to 0.1 mm, thereby achieving high dimensional accuracy of the core 1. Fig.10 ) is engaged with the outer peripheral surface of the yoke 11 and fixed, it is easy to fix the annular component relative to the outer peripheral surface of the yoke 11. In addition, in the iron core 1, if the roundness of the outer peripheral surface of the yoke 11 is less than or equal to 0.1 mm, the outer peripheral surfaces of the yoke 11 of each iron core 10 constituting the iron core 1 are aligned in the circumferential direction. That is, the radial position deviation of each iron core 10 is small, and the position of the tooth portion 12 of each iron core 10 is aligned in the circumferential direction. As described later, when the rotating electric machine 300 (refer to Fig.12 ), each end face 41 of the tooth portion 12 is arranged to be opposite to the magnet 220 of the rotor 200. The radial position deviation of each iron core piece 10 is small, so that in the rotating electric machine 300, the relative area of ​​the end face 41 of each tooth portion 12 and the magnet 220 of the rotor 200 becomes uniform. As a result, the cogging effect and the like can be reduced, and the degradation of the characteristics of the rotating electric machine 300 can be suppressed. When measuring the roundness of the outer peripheral surface of the yoke 11, an evaluation is performed by point measurement so that the side surfaces 20, 30 of the yoke 11 of the adjacent iron core pieces 10 are not included (refer to Figure 4 , Figure 5 ) are formed at the connection points between them.

[0139] 〈Height of each end surface of the tooth〉

[0140] In the core 1, it is preferred that the difference between the position of the end face 41 of the highest tooth 12 and the position of the end face 41 of the lowest tooth 12 among the teeth 12 of the plurality of core sheets 10 is less than or equal to 0.15 mm. Figure 3 The figure shows the axial height position from the surface of the yoke 11 opposite to the protruding side of the teeth 12, that is, the lower surface, to the end surface 41 when the lower surface is placed on a flat surface. Figure 3 In the figure, the height position of the end face 41 of the tooth portion 12 is represented by Ht. The difference between the position of the end face 41 of the highest tooth portion 12 and the position of the end face 41 of the lowest tooth portion 12 is less than or equal to 0.15 mm, so that the fluctuation of the height of each end face 41 of the tooth portion 12 is small. As described later, when the rotating electric machine 300 (see Fig.12 ), each end face 41 of the tooth portion 12 is arranged to face the magnet 220 of the rotor 200. The fluctuation of the height of each end face 41 of the tooth portion 12 is small, thereby in the rotating electric machine 300, the fluctuation of the interval between each end face 41 of the tooth portion 12 and the rotor 200 can be reduced. As a result, the cogging effect and the like can be reduced, and the degradation of the characteristics of the rotating electric machine 300 can be suppressed.

[0141] 〈Flatness of the end surface of the tooth〉

[0142] The flatness of the end face 41 of the tooth portion 12 is preferably less than or equal to 0.2 mm. Fig.12 ), the end surface 41 of the tooth portion 12 can be brought close to the rotor 200 so that they face each other. This can suppress degradation of the characteristics of the rotating electrical machine 300.

[0143] In this example, the side surfaces of the yokes 11 of the adjacent core sheets 10 are bonded to each other, thereby integrating the plurality of core sheets 10 combined into a ring shape. Fig. 9 As shown in the example, in the case of a plate-like member 80 disposed on the lower side, opposite to the protruding side of the tooth portion 12, of the yoke 11 of the adjacent core sheet 10, the lower surface, opposite to the yoke 11, may also be bonded to the plate-like member 80. In this case, the plurality of core sheets 10 are fixed to the plate-like member 80 in a state of being combined in a ring shape and integrated.

[0144] Core 1 Fig.10As shown in the example, there can be an annular component 90 that is engaged with the outer peripheral surface of the yoke 11 of the multiple iron core sheets 10 combined into an annular shape. The annular component 90 is fixed relative to the multiple iron core sheets 10 constituting the iron core 1 by the contraction force in the inner diameter direction. In this example, the annular component 90 is heat-fitted on the outer peripheral surface of the yoke 11. The annular component 90 is formed of the following material and size, that is, the inner diameter at room temperature before heat-fitting is smaller than the outer diameter of the yoke 11 of the iron core 1, and the inner diameter is made larger than the outer diameter of the yoke 11 of the iron core 1 by heating during heat-fitting. Figure 2 In FIG. 1 , the outer diameter of the yoke 11 is represented by Do. Figure 2 In the figure, Di represents the inner diameter of the yoke 11. The order of heat-fitting the annular component 90 and the plurality of iron core sheets 10 combined into an annular shape is as follows. The annular component 90 is heated to a predetermined temperature to expand, thereby making its inner diameter larger than the outer diameter of the yoke 11 of the iron core 1. The annular component 90, after being heated to expand the inner diameter, is fitted into the outer peripheral surface of the yoke 11 of the iron core 1. The annular component 90 is cooled to shrink, thereby tightening the outer periphery of the iron core 1 through the annular component 90.

[0145] In the case of the annular member 90, the plurality of core sheets 10 can be integrated. In addition, the outer periphery of the yoke 11 can be tightened by the contraction force in the inner diameter direction of the annular member 90, and the plurality of core sheets 10 can be firmly tightened. Either the plate-like member 80 or the annular member 90 described above can be used, or both can be used.

[0146] 〈Powder Core〉

[0147] The core piece 10 is formed by a powdered magnetic core. The powdered magnetic core is obtained by compression molding soft magnetic powder. The soft magnetic powder is a collection of multiple coated soft magnetic particles having an insulating coating on the surface of the soft magnetic particles. That is, the powdered magnetic core is composed of a collection of multiple coated soft magnetic particles. The soft magnetic particles are preferably iron-based particles composed of at least one of pure iron and an iron-based alloy. Pure iron refers to iron with a purity greater than or equal to 99% by mass. The iron-based alloy includes at least one selected from the group consisting of Fe (iron) -Si (silicon) alloys, Fe (iron) -Al (aluminum) alloys, Fe (iron) -Cr (chromium) -Al (aluminum) alloys and Fe (iron) -Cr (chromium) -Si (silicon) alloys. The soft magnetic particles constituting the powdered magnetic core may be particles consisting only of pure iron, particles consisting only of an iron-based alloy, or mixed particles consisting of particles consisting of pure iron and particles consisting of an iron-based alloy. Examples of the insulating coating include phosphate coating and silica coating.

[0148] Pure iron or the above-mentioned iron-based alloy is a relatively soft material. Therefore, the soft magnetic particles are iron-based particles composed of pure iron or the above-mentioned iron-based alloy, and thus the soft magnetic particles are easily deformed when the powdered magnetic core is formed. Thus, a powdered magnetic core with high density and high dimensional accuracy is obtained. By making the powdered magnetic core high-density, the mechanical strength and magnetic properties of the core piece 10 can be improved. In addition, there is an insulating coating on the surface of the soft magnetic particles, which can improve the electrical insulation between the soft magnetic particles. Therefore, the iron loss of the core piece 10 caused by eddy current loss can be reduced.

[0149] In addition, the insulating coating preferably includes a phosphate coating. The phosphate coating has high adhesion to the iron-based particles and excellent deformability. Therefore, the insulating coating includes a phosphate coating, which makes it easy to follow the deformation of the iron-based particles when the powder magnetic core is formed. As a result, the insulating coating is not easily damaged, and the iron loss of the iron core 10 can be reduced.

[0150] The relative density of the powder core is preferably greater than or equal to 90%. By increasing the density of the powder core, the mechanical strength and magnetic properties of the core piece 10 can be improved. The relative density is more preferably greater than or equal to 93%. The relative density refers to the ratio (%) of the actual density of the powder core to the true density of the powder core. The true density refers to the theoretical density when no voids are included inside. The true density of the powder core can also be calculated based on the true density of the soft magnetic powder used. Regarding the relative density of the powder core, for example, it can be calculated as [(molding density of the powder core / true density of the powder core)×100]. Regarding the molding density of the powder core, the powder core can be immersed in oil so that the oil is impregnated in the powder core, and it can be calculated based on [oil-containing density×(mass of the powder core before oiling / mass of the powder core after oiling)]. The oil-containing density is the value obtained by dividing the mass of the powder core after oiling by the volume. The volume of the powder magnetic core can be measured typically by a liquid replacement method.

[0151] The core piece 10 composed of a powder magnetic core can be formed by, for example, Figure 6 The die 5 as illustrated in the figure is used for molding. The die 5 comprises: a die 50 having a die hole 51; and an upper punch 60 and a lower punch 70, which are engaged with the die hole 51 of the die 50. The die 50 molds the peripheral surface of the yoke 11. The upper punch 60 molds the lower surface of the yoke 11, i.e., the surface on the opposite side of the protruding side of the tooth portion 12. The lower punch 70 comprises a first lower punch 71 and a second lower punch 72. The first lower punch 71 molds the upper surface of the yoke 11, i.e., the surface on the protruding side of the tooth portion 12, and molds the peripheral surface of the tooth portion 12. A through hole for inserting and passing the second lower punch 72 is formed in the axial direction in the first lower punch 71. The second lower punch 72 is inserted through the first lower punch 71 to mold the end surface 41 of the tooth portion 12.

[0152] When the core sheet 10 is formed using the die 5, the lower punch 70 is fitted into the die hole 51 of the die 50, and the soft magnetic powder is filled in the die hole 51. Then, the upper punch 60 and the lower punch 70 compress the soft magnetic powder, and the core sheet 10 is formed.

[0153] The average particle size of the soft magnetic powder is, for example, set to be greater than or equal to 20 μm and less than or equal to 300 μm, and further set to be greater than or equal to 40 μm and less than or equal to 250 μm. By setting the average particle size of the soft magnetic powder within the above range, it is easy to handle and easy to compress and mold. The average particle size of the soft magnetic powder refers to the particle size measured using a laser diffraction / scattering particle size / particle size distribution measuring device, and the cumulative mass is 50% of the mass of all particles.

[0154] By increasing the molding pressure when compressing the soft magnetic powder, it is possible to increase the density of the core piece 10. The molding pressure is, for example, 700 MPa or more, and further, 2000 MPa or more.

[0155] The die hole 51 of the punch die 50 is as shown in FIG. Figure 7 As shown, it is formed with the yoke 11 (refer to Figure 5 ) is formed in a shape corresponding to the peripheral surface of the die hole 51. One side surface 52 of the die hole 51 is a portion for molding the side surface 20 of the yoke 11. Concave portions 521, 522 and a convex portion 523 for molding the convex portions 21, 22 and the concave portion 23 are formed on the side surface 52 in correspondence with the shape of the side surface 20 of the yoke 11 (see also Figure 8 The other side surface 53 of the die hole 51 is a portion for molding the side surface 30 of the yoke 11. The side surface 53 is formed with convex portions 531, 532 and a concave portion 533 corresponding to the shape of the side surface 30 of the yoke 11 to mold the concave portions 31, 32 and the convex portion 33.

[0156] When forming the core sheet 10, the raw material powder is compressed, so that stress acts on the die 50 in the direction in which the die hole 51 is pressed and expanded. Figure 8 As shown, stress acts from both sides on the protrusion 523 of the die 50 sandwiched between the protrusions 21 and 22 of the yoke 11. Figure 8 In FIG. 5 , the stress acting on the convex portion 523 is indicated by a hollow arrow. Figure 3As described above, the interval between the adjacent convex parts 21 and 22 is less than or equal to 80% of the length of the side surface of the yoke, for example, approximately less than or equal to 40 mm, so the stresses acting on the convex parts 523 are offset and reduced. Therefore, the stress acting on the side surface 52 of the die 50 can be reduced, and damage to the die 50 can be suppressed. In addition, in this example, the adjacent convex parts 21 and 22 are symmetrical in shape, so the magnitude of the stress acting from both sides of the convex part 523 is substantially equal. As a result, the stress acting on the convex part 523 is offset, thereby more effectively suppressing damage to the die 50.

[0157] On the other hand, in the side surface 53 of the die 50, the concave portion 533 is pressed from the raw material powder in a manner of being expanded by pressing during molding. The concave portion 533 is sandwiched on both sides by the convex portions 531 and 532 having a large distance to the outer peripheral edge of the die 50, so it is not easily damaged by the die due to stress.

[0158] <Stator>

[0159] Reference Fig.11 , the stator 100 involved in the embodiment is described. The stator 100 is used in an axial gap type rotating electric machine. The stator 100 has an iron core 1 and a coil 110 arranged on each tooth portion 12 of an iron core sheet 10 constituting the iron core 1. The coil 110 is a cylindrical coil in which a winding is wound in a spiral shape. In this example, the coil 110 is a triangular cylindrical flat-standing winding coil in which an enameled flat wire is used for the winding.

[0160] <Rotary electric machines>

[0161] Reference Fig.12 The rotating electrical machine 300 according to the embodiment will be described. The rotating electrical machine 300 may be a motor or a generator. The rotating electrical machine 300 includes a rotor 200 and a stator 100. The rotating electrical machine 300 is an axial gap type rotating electrical machine in which the rotor 200 and the stator 100 are arranged to face each other in the direction of the rotating axis.

[0162] The stator 100 and the rotor 200 are accommodated in a cylindrical housing 310. Disc-shaped plates 320 are attached to both ends of the housing 310. Through holes are formed in the centers of the two plates 320, and the rotating shaft 330 passes through the housing 310.

[0163] (Rotor)

[0164] The rotor 200 has a plurality of flat-plate-shaped magnets 220 and an annular retaining plate 210 for supporting the magnets 220. The planar shape of the magnet 220 is a shape roughly corresponding to the end face 41 of the tooth portion 12. When the shape of the end face 41 of the tooth portion 12 is a triangle, the planar shape of the magnet 220 includes, for example, a triangle or a trapezoid. The retaining plate 210 is fixed to the rotating shaft 330 and rotates together with the rotating shaft 330. Each magnet 220 is embedded in the retaining plate 210. The magnets 220 are arranged at equal intervals in the circumferential direction of the rotating shaft 330. In addition, the magnets 220 are magnetized in the axial direction of the rotating shaft 330. The magnetization directions of the magnets 220 adjacent to each other in the circumferential direction are opposite to each other.

[0165] (stator)

[0166] The stator 100 is configured such that the end surface 41 of the tooth portion 12 faces the magnet 220 of the rotor 200. The stator 100 is fixed to the housing 310 by fitting the outer peripheral surface of the yoke portion 11 of the core 1 with the inner peripheral surface of the housing 310. In addition, an annular bearing 340 is mounted on the inner peripheral surface of the yoke portion 11 to rotatably support the rotating shaft 330.

[0167] {Effects of Implementation Methods}

[0168] The core 1 , the stator 100 , and the rotating electrical machine 300 according to the above-described embodiment have the following effects.

[0169] In the core piece 10 constituting the core 1, a plurality of protrusions 21 and 22 are provided on one side surface 20 of the yoke 11, and a plurality of recesses 31 and 32 corresponding to the protrusions 21 and 22 are provided on the other side surface 30. Therefore, when the plurality of core pieces 10 are combined into a ring shape, the yokes 11 of the adjacent core pieces 10 can be positioned relative to each other by fitting the protrusions 21 and 22 and the recesses 31 and 32. Thus, the radial displacement of the adjacent core pieces 10 can be suppressed. Therefore, the core 1 is easy to align the adjacent core pieces 10, and has excellent assembly properties.

[0170] The stator 100 has excellent assemblability because it includes the core 1. The rotating electrical machine 300 has the stator 100 having excellent assemblability because it has high productivity.

[0171] [Trial Calculation Example 1]

[0172] The stress distribution acting on the die 50 when the core piece 10 described in the embodiment is molded by the die 5 is analyzed by CAE (Computer Aided Engineering).

[0173] "NX Nastran" manufactured by Siemens was used for the stress analysis. The analysis conditions were set as follows: The molding pressure was set to 980 MPa. The physical property values ​​of the die 50 were set to Young's modulus: 206000 MPa, and Poisson's ratio: 0.3.

[0174] The dimensions of the designed core sheet 10 are set as follows.

[0175] The thickness of the yoke 11 ( Figure 3 Middle Ty): 5mm

[0176] Length of side surface 20 of yoke 11: 40 mm

[0177] Size of protrusions 21, 22: 3 mm

[0178] Ratio of distance from the recesses 31 and 32 to the root of the tooth 12: 70%

[0179] Minimum curvature radius of convex parts 21, 22 and concave parts 31, 32: 3.0 mm

[0180] Based on the results of stress analysis obtained by CAE, the maximum stress generated by the protrusion 523 on the side 52 of the die 50 was obtained. In Test Example 1, the interval between the protrusions 21 and 22 was changed, and the ratio of the interval between the protrusions to the length of the yoke side surface was changed, and the maximum stress in each case was obtained. The results are shown in Table 1.

[0181] [Table 1]

[0182]

[0183] As can be seen from Table 1, the smaller the interval between the protrusions, the smaller the maximum stress at the protrusions of the die during forming. In particular, it can be seen that when the interval between the protrusions is less than or equal to 80% of the side length of the yoke, the maximum stress generated at the protrusions can be reduced to less than or equal to 1500 MPa.

[0184] [Trial Example 1]

[0185] A core sheet having the same structure as the core sheet 10 described in the embodiment was produced and evaluated.

[0186] The dimensions of the core piece 10 are set as follows.

[0187] The thickness of the yoke 11 ( Figure 3 Medium Ty): 5mm

[0188] The outer diameter of the yoke 11 ( Figure 2 Middle Do): 120mm

[0189] The inner diameter of the yoke 11 ( Figure 2 Middle bottom): 40mm

[0190] The height of the end face 41 of the tooth portion 12 ( Figure 3 Middle Ht): 18mm

[0191] Length of side surface 20 of yoke 11: 40 mm

[0192] Ratio of the interval between the convex parts 21 and 22: 57%

[0193] Size of protrusions 21, 22: 3 mm

[0194] Ratio of distance from the recesses 31 and 32 to the root of the tooth 12: 70%

[0195] Minimum curvature radius of convex parts 21, 22 and concave parts 31, 32: 3.0 mm

[0196] The raw material soft magnetic powder used was a powder of coated soft magnetic particles having phosphate coating on the surface of pure iron powder. The average particle size of the soft magnetic powder was 50 μm. The molding pressure was set to 980 MPa. The relative density of the core piece 10 formed of the obtained powder magnetic core was 92%.

[0197] Six core sheets 10 were manufactured under the same conditions, and the core sheets 10 were combined in a ring shape to manufacture the core 1. One core sheet 10 had two teeth 12. The total number of teeth 12 was 12. The obtained core 1 was evaluated as follows.

[0198] 〈Roundness of yoke〉

[0199] The roundness of the outer peripheral surface of the yoke was measured using a commercially available 3D shape measuring machine. Specifically, the roundness was measured by point measurement using a "VR-3200" manufactured by KEYENCE. As a result, the roundness of the outer peripheral surface of the yoke was less than or equal to 0.1 mm.

[0200] 〈Flatness of the end surface of the tooth〉

[0201] The flatness of the end faces of the teeth was measured using a commercially available 3D shape measuring machine, specifically, "VR-3200" manufactured by KEYENCE Corp. As a result, the flatness of each end face of the 12 teeth was less than or equal to 0.1 mm.

[0202] 〈Height of the end face of the tooth〉

[0203] With the lower surface of the yoke placed on a flat surface, the height position of each end face of a total of 12 teeth was measured using a commercially available 3D shape measuring machine, specifically, a "VR-3200" manufactured by KEYENCE. Then, the difference between the position of the end face of the highest tooth and the position of the end face of the lowest tooth was found, and the difference was 0.15 mm.

[0204] Description of the label

[0205] 1 Core

[0206] 10, 10a, 10b, 10c, 10d, 10e, 10f Iron core

[0207] 11 Yoke

[0208] 12, 12a, 12b teeth

[0209] 20, 30 side

[0210] 21, 22 convex part

[0211] 23 recess

[0212] 31, 32 concave part

[0213] 33 convex part

[0214] 41 End face

[0215] 5. Mould

[0216] 50 Die

[0217] 51 Die Hole

[0218] 52, 53 side

[0219] 521, 522 concave part

[0220] 523 convex part

[0221] 531, 532 convex part

[0222] 533 recess

[0223] 60 Upper punch

[0224] 70 Lower punch

[0225] 71 1st lower punch 72 2nd lower punch

[0226] 80 Plate-like parts

[0227] 90 Ring parts

[0228] 100 Stator

[0229] 110 Coil

[0230] 200 rotor

[0231] 210 holding plate 220 magnet

[0232] 300 Rotating motor

[0233] 310 Shell 320 Plate

[0234] 330 Rotating shaft 340 Bearing

[0235] L A , L B Middle Line

[0236] L1, L2, Lc Straight line La Center line

[0237] a, b points l vertices m, n intersection points

[0238] Ty Thickness Ht Height Position

[0239] Do Outer diameter Di Inner diameter

Claims

1. An iron core used in an axial gap type rotating electrical machine, The core is annular and has a plurality of core sheets which divide the core in the circumferential direction. The core sheet is formed of a powder magnetic core and has: a yoke; and a tooth portion, which is integrally formed with the yoke portion and protrudes from the yoke portion in the axial direction, The yoke comprises: a plurality of protrusions provided on a side surface connected to a yoke portion of an adjacent core sheet; and A plurality of recessed portions, which correspond to the convex portions and are provided on the other side surface connected to the yoke portion of another adjacent core sheet, The interval between the protrusions is less than or equal to 80% of the length of the side surface of the yoke determined by the straight-line distance between the outer periphery and the inner periphery of the yoke.

2. The core according to claim 1, wherein: When the yoke is viewed from above from the protruding side of the tooth portion, a middle line between the opposite side surfaces of the tooth portion and the tooth portion of another adjacent iron core sheet is set as a reference line, and a distance from the recessed portion to the root of the tooth portion is greater than or equal to 20% of a distance from the reference line to the root of the tooth portion.

3. The core according to claim 1 or 2, wherein: The size of the protrusion is greater than or equal to 1 mm and less than or equal to 10 mm.

4. The core according to claim 1 or 2, wherein: The minimum curvature radius of the convex portion and the concave portion when the yoke portion is viewed from above from the convex side of the tooth portion is greater than or equal to 1.0 mm.

5. The core according to claim 1 or 2, wherein: The adjacent convex portions are symmetrical with respect to a center line between the convex portions.

6. The core according to claim 1 or 2, wherein: The thickness of the yoke is greater than or equal to 1.0 mm and less than or equal to 10 mm.

7. The core according to claim 1 or 2, wherein: The powder magnetic core is composed of a plurality of coated soft magnetic particles having an insulating coating on the surface of the soft magnetic particles. The soft magnetic particles are iron-based particles composed of at least one of pure iron and an iron-based alloy. The iron-based alloy is at least one selected from the group consisting of Fe—Si-based alloys, Fe—Al-based alloys, Fe—Cr—Al-based alloys, and Fe—Cr—Si-based alloys.

8. The core according to claim 7, wherein: The insulating coating comprises a phosphate coating.

9. The core according to claim 7, wherein: The relative density of the powder magnetic core is greater than or equal to 90%.

10. The core according to claim 1 or 2, wherein: A ring-shaped member is provided, and the ring-shaped member is fitted into the outer peripheral surface of the yoke portion of the plurality of core sheets, The annular member is fixed to the plurality of core sheets by a contraction force in the inner diameter direction thereof.

11. The core according to claim 1 or 2, wherein: The side surfaces of the yokes of adjacent core sheets are bonded to each other, or, A plate-like member is provided. The plate-like member is arranged on the side of the yoke of the adjacent core sheet opposite to the side on which the teeth protrude. The surface of the yoke on the opposite side is bonded to the plate-like member.

12. The core according to claim 1 or 2, wherein: A difference between a position of an end surface of a highest tooth portion and a position of an end surface of a lowest tooth portion among the teeth portions of the plurality of core sheets is less than or equal to 0.15 mm.

13. The core according to claim 1 or 2, wherein: When the plurality of core sheets are combined in a ring shape, the roundness of the outer peripheral surface of the yoke is less than or equal to 0.1 mm.

14. The core according to claim 1 or 2, wherein: The flatness of the end surface of the tooth portion is less than or equal to 0.2 mm.

15. A stator, which is a stator of an axial gap type rotating electrical machine, The stator has: The iron core according to any one of claims 1 to 14; and The coil is arranged on each of the teeth of the core sheet constituting the core.

16. A rotating electrical machine comprising a rotor and a stator, wherein the rotor and the stator are arranged to face each other in the axial direction and are of an axial gap type. In the rotating electrical machine, The stator is the stator according to claim 15.

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