Core piece, stator core, stator, axial gap motor, core piece manufacturing device, and core piece manufacturing method

Abstract

This core piece is of a stator core of an axial gap motor, the core piece being obtained by pressing a soft magnetic powder which has been coated with an insulating material. The core piece comprises: a tooth part that has a peripheral surface around which a winding is wound; a first flange part that is connected to an end part on one side of the tooth part; and a second flange part that is connected to an end part on the reverse side of the tooth part from the first flange part. The peripheral surface of the tooth part has: an inner peripheral part; an outer peripheral part that is located on the reverse side from the inner peripheral part; and a first side peripheral part and a second side peripheral part that are connected to the inner peripheral part and the outer peripheral part so as to face each other. A first inner-peripheral-side side end, which is an end part on the side of the first side peripheral part that is toward the inner peripheral part, approaches a second inner-peripheral-side side end, which is an end part on the side of the second side peripheral part that is toward the inner peripheral part, the further toward the inner peripheral part.

Description

Core piece, stator core, stator, axial gap motor, core piece manufacturing device, and core piece manufacturing method

[0001] The present invention relates to a core piece of a stator core of an axial gap motor, a stator core of an axial gap motor, a stator of an axial gap motor, an axial gap motor, a core piece manufacturing device, and a core piece manufacturing method.

[0002] Patent Document 1 describes a core piece for constructing a stator core of an axial gap motor. The core piece is a powder-molded body and includes a columnar first member (teeth portion) extending in the axial direction of the stator core, a plate-shaped second member (first flange portion) provided at a first axial end of the first member, and a plate-shaped third member (second flange portion) provided at a second axial end of the first member. Each of the first, second, and third members has an outer circumferential surface disposed on the outer circumferential side of the stator core, an inner circumferential surface disposed on the inner circumferential side of the stator core, and a first side surface and a second side surface connected to the outer circumferential surface. To enable the first, second, and third members to be integrally powder-molded, the outer circumferential end of the first side surface and the outer circumferential end of the second side surface are parallel to each other.

[0003] Patent No. 6987327

[0004] In the core pieces described in Patent Document 1, parallel surfaces are formed at the inner peripheral end of the first side surface and the inner peripheral end of the second side surface. Therefore, when windings are wound around the teeth, the windings are significantly floating above the teeth near the connections between the first and second side surfaces and the inner peripheral surface. If the air gap between the windings and the teeth becomes large, the magnetic flux density decreases, resulting in reduced motor performance.

[0005] Therefore, an object of the present disclosure is to provide a core piece, a stator core, a stator, an axial gap motor, a core piece manufacturing device, and a core piece manufacturing method that can increase magnetic flux density.

[0006] [1] The core piece according to the present disclosure is a core piece for a stator core of an axial gap motor, formed by pressing soft magnetic powder coated with an insulating material, and comprising: teeth portions having a peripheral surface extending in a first direction and around which a winding is wound; first flange portions connected to one end of the teeth portions in the first direction and protruding from the teeth portions in a direction perpendicular to the first direction; and second flange portions connected to the end of the teeth portions opposite the first flange portions in the first direction and protruding from the teeth portions in a direction perpendicular to the first direction. The peripheral surface of the teeth portions has an inner peripheral portion located on one side in a second direction perpendicular to the first direction, an outer peripheral portion located opposite the inner peripheral portion in the second direction, and a first side peripheral portion and a second side peripheral portion connected to the inner peripheral portion and the outer peripheral portion, and the first inner peripheral portion, which is the end of the first side peripheral portion on the inner peripheral portion side, approaches the inner peripheral portion toward the second inner peripheral portion, which is the end of the second side peripheral portion on the inner peripheral portion side, as it approaches the inner peripheral portion.

[0007] In this core piece, the circumferential surface of the tooth around which the winding is wound has an inner circumferential portion, an outer circumferential portion, a first side circumferential portion, and a second side circumferential portion, and the first inner circumferential end portion, which is the inner circumferential end of the first side circumferential portion, approaches the inner circumferential portion toward the second inner circumferential end portion, which is the inner circumferential end of the second side circumferential portion, as it approaches the inner circumferential portion. Therefore, when the winding is wound around the circumferential surface of the tooth, the winding can be easily aligned along the first inner circumferential end portion and the inner circumferential portion. This makes it possible to suppress floating of the winding from the tooth near the connection between the first inner circumferential end portion and the inner circumferential portion, thereby increasing the magnetic flux density.

[0008] [2] In the core piece according to [1], the first inner peripheral end portion may have a curved surface that curves toward the second inner peripheral end portion. In this core piece, the first inner peripheral end portion has a curved surface that curves toward the second inner peripheral end portion, which makes it easier to align the winding along the first inner peripheral end portion and the inner peripheral portion.

[0009] [3] In the core piece according to [1], the first inner peripheral end portion may be an inclined surface inclined toward the second inner peripheral end portion. In this core piece, since the first inner peripheral end portion is an inclined surface inclined toward the second inner peripheral end portion, the first inner peripheral end portion can be easily formed.

[0010] [4] In the core lamination according to any one of [1] to [3], the second inner peripheral end portion may be inclined toward the first inner peripheral end portion as it approaches the inner peripheral portion. In this core lamination, the second inner peripheral end portion is inclined toward the first inner peripheral end portion as it approaches the inner peripheral portion, so that when the winding is wound around the circumferential surface of the tooth portion, the winding can be easily aligned along the second inner peripheral end portion and the inner peripheral portion. This makes it possible to suppress the winding from floating from the tooth portion near the connection portion between the second inner peripheral end portion and the inner peripheral portion, thereby further increasing the magnetic flux density.

[0011] [5] In the core piece according to [4], the second inner peripheral end portion may have a curved surface that curves toward the first inner peripheral end portion. In this core piece, the second inner peripheral end portion has a curved surface that curves toward the first inner peripheral end portion, which makes it easier to align the winding along the second inner peripheral end portion and the inner peripheral portion.

[0012] [6] In the core piece according to [4], the second inner peripheral end portion may be an inclined surface inclined toward the first inner peripheral end portion. In this core piece, since the second inner peripheral end portion is an inclined surface inclined toward the first inner peripheral end portion, the second inner peripheral end portion can be easily formed.

[0013] [7] A stator core according to the present disclosure is a stator core for an axial gap motor, and includes the core pieces according to any one of [1] to [6]. Because this stator core includes the core pieces described above, it is possible to increase the magnetic flux density.

[0014] [8] A stator according to the present disclosure is a stator for an axial gap motor, and includes the stator core according to [7] and a winding wound around the core pieces of the stator core. Because this stator has the stator core described above, it is possible to increase the magnetic flux density.

[0015] [9] An axial gap motor according to the present disclosure includes the stator described in [8] and a rotor rotatably disposed relative to the stator. Because this axial gap motor has the above-described stator, it is possible to increase the magnetic flux density.

[0016]

[10] A core piece manufacturing apparatus according to the present disclosure is a core piece manufacturing apparatus for manufacturing the core piece according to any one of [1] to [6], comprising: a die having a forming hole; an upper punch inserted into the forming hole from above; a first lower punch inserted into the forming hole from below; and a second lower punch inserted into the forming hole from below, wherein the upper punch has a teeth upper pressing surface that forms teeth portions of the core piece together with the first lower punch; and a first flange upper pressing surface and a second flange upper pressing surface that form first and second flange portions of the core piece together with the second lower punch, has a lower pressing surface for the teeth that forms the teeth between itself and the upper punch, and the second lower punch has a lower pressing surface for the first flange and a lower pressing surface for the second flange that form a first flange and a second flange between itself and the upper punch, the upper pressing surface for the teeth of the upper punch has a shape corresponding to the outer periphery of the teeth, and the lower pressing surface for the teeth of the first lower punch has a bottom surface shaped relative to the inner periphery of the teeth, a first bottom surface shaped corresponding to a first inner periphery end portion of the teeth, and a second bottom surface shaped corresponding to a second inner periphery end portion of the teeth.

[0017] In this core piece manufacturing apparatus, the upper punch has an upper pressing surface for the teeth that forms the teeth of the core piece together with the first lower punch, and an upper pressing surface for the first flange and an upper pressing surface for the second flange that form the first and second flanges of the core piece together with the second lower punch; the first lower punch has a lower pressing surface for the teeth that forms the teeth together with the upper punch; the second lower punch has a lower pressing surface for the first flange and a lower pressing surface for the second flange that form the first and second flanges together with the upper punch; the upper pressing surface for the teeth of the upper punch has a shape corresponding to the outer periphery of the teeth; and the lower pressing surface for the teeth of the first lower punch has a bottom surface shaped relative to the inner periphery of the teeth, a first bottom surface shaped corresponding to the first inner periphery end of the teeth, and a second bottom surface shaped corresponding to the second inner periphery end of the teeth. Therefore, the above-mentioned core pieces can be compacted by inserting a first lower punch and a second lower punch into the molding hole of the die, supplying soft magnetic powder coated with an insulating material into the molding hole from above, inserting an upper punch into the molding hole, and pressing the soft magnetic powder between the upper punch and the first lower punch and the second lower punch, thereby manufacturing core pieces with an increased magnetic flux density.

[0018]

[11] In the core piece manufacturing apparatus described in

[10] , the first lower punch may have a first main lower punch and a first auxiliary lower punch that is movable up and down relative to the first main lower punch, and the first main lower punch may have a portion of the lower tooth pressing surface, and the first auxiliary lower punch may have the remaining portion of the lower tooth pressing surface. In this core piece manufacturing apparatus, the first lower punch has a portion of the lower tooth pressing surface, and the first auxiliary lower punch has the remaining portion of the lower tooth pressing surface and is movable up and down relative to the first main lower punch. Therefore, after the core piece is powder-compressed, the first auxiliary lower punch can be moved upward relative to the first main lower punch to easily remove the core piece from the first lower punch.

[0019]

[12] In the core piece manufacturing apparatus described in

[11] , the first main lower punch may have a first-side bottom surface and a portion of the bottom surface of the lower tooth pressing surface, and the first auxiliary lower punch may have the remaining portion of the bottom surface of the lower tooth pressing surface. In this core piece manufacturing apparatus, the first main lower punch has the first-side bottom surface and a portion of the bottom surface of the lower tooth pressing surface, and the first auxiliary lower punch has the remaining portion of the bottom surface of the lower tooth pressing surface. Therefore, after the core piece has been compacted, the first auxiliary lower punch can be moved upward relative to the first main lower punch to easily remove the core piece from the first lower punch.

[0020]

[13] The core piece manufacturing method according to the present disclosure is a core piece manufacturing method for manufacturing core pieces for a stator core of an axial gap motor using the core piece manufacturing apparatus described in any one of

[10] to

[12] , and includes: a lower punch insertion process for inserting a first lower punch and a second lower punch into a forming hole of a die; a powder supply process for supplying soft magnetic powder coated with an insulating material from above into the forming hole after the lower punch insertion process; a pressing process for inserting an upper punch into the forming hole after the powder supply process, and pressing the soft magnetic powder supplied into the forming hole with the upper punch and the first lower punch and the second lower punch to form a core piece formed by pressing the soft magnetic powder; and an extraction process for extracting the core piece from the forming hole after the pressing process.

[0021] In this core piece manufacturing method, the first lower punch and the second lower punch are inserted into the molding hole, soft magnetic powder coated with an insulating material is supplied to the molding hole from above, the upper punch is inserted into the molding hole, and the soft magnetic powder supplied to the molding hole is pressed by the upper punch and the first lower punch and the second lower punch, thereby compacting the above-mentioned core pieces. After the core pieces are compacted, they are removed from the molding hole, thereby producing core pieces with an increased magnetic flux density.

[0022]

[14] In the core piece manufacturing method described in

[13] , the upper punch and the second lower punch may be moved upward in the ejection step. In this core piece manufacturing apparatus, after the core piece is powder-compressed, the upper punch and the second lower punch may be moved upward to easily eject the core piece from the molding hole.

[0023]

[15] In the core piece manufacturing method according to

[13] or

[14] , the first lower punch may have a first main lower punch having a portion of the lower tooth pressing surface and a first auxiliary lower punch having the remaining portion of the lower tooth pressing surface and movable up and down relative to the first main lower punch, and in the ejection step, the upper punch may be moved upward and the first auxiliary lower punch may be moved upward relative to the first main lower punch. In this core piece manufacturing method, after the core piece is powder-compressed, the upper punch may be moved upward and the first auxiliary lower punch may be moved upward relative to the first main lower punch, thereby ejecting the core piece from the first main lower punch and easily ejecting the core piece from the molding hole.

[0024] The magnetic flux density can be increased.

[0025] FIG. 1 is a schematic cross-sectional view showing an axial gap motor according to an embodiment. FIG. 2 is a schematic view showing a stator core according to an embodiment. FIG. 3 is a perspective view showing a core piece according to an embodiment. FIG. 4 is a perspective view showing a core piece according to an embodiment. FIG. 5 is a front view showing a core piece according to an embodiment. FIG. 6 is a bottom view showing a core piece according to an embodiment. FIG. 7 is a cross-sectional view taken along line VII-VII shown in FIG. 6. FIG. 8 is an exploded perspective view showing a core piece manufacturing apparatus according to a first embodiment. FIG. 9 is a front view showing a core piece manufacturing apparatus according to a first embodiment. FIG. 10 is a side view showing a core piece manufacturing apparatus according to a first embodiment. FIG. 11 is a plan view showing a portion of a die. FIG. 12 is a cross-sectional view taken along line XII-XII shown in FIG. 11. FIG. 13 is a cross-sectional view taken along line XIII-XIII shown in FIG. 11. FIG. 14 is a perspective view showing an upper punch. FIG. 15 is a perspective view showing a first lower punch. FIG. 16 is a perspective view showing a first lower punch. FIG. 17 is a front view showing a first lower punch. FIG. 18 is a cross-sectional view showing a lower punch insertion step. FIG. 19 is a cross-sectional view showing the lower punch insertion step. FIG. 20 is a cross-sectional view showing the powder supplying step. FIG. 21 is a cross-sectional view showing the powder supplying step. FIG. 22 is a cross-sectional view showing the pressing step. FIG. 23 is a cross-sectional view showing the pressing step. FIG. 24 is a cross-sectional view showing the ejection step. FIG. 25 is a cross-sectional view showing the ejection step. FIG. 26 is an exploded perspective view showing a core piece manufacturing apparatus according to a second embodiment. FIG. 27 is a front view showing a core piece manufacturing apparatus according to a second embodiment. FIG. 28 is a side view showing a core piece manufacturing apparatus according to the second embodiment. FIG. 29 is a cross-sectional view showing the lower punch insertion step. FIG. 30 is a cross-sectional view showing the lower punch insertion step. FIG. 31 is a cross-sectional view showing the powder supplying step. FIG. 32 is a cross-sectional view showing the powder supplying step. FIG. 33 is a cross-sectional view showing the pressing step. FIG. 34 is a cross-sectional view showing the pressing step. FIG. 35 is a cross-sectional view showing the ejection step. FIG. 36 is a cross-sectional view showing the ejection step.

[0026] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. Also, in the drawings, dimensional proportions and the like have been appropriately changed to make the explanation easier to understand.

[0027] [Axial Gap Motor] Fig. 1 is a schematic cross-sectional view showing an axial gap motor according to an embodiment. As shown in Fig. 1, the axial gap motor 1 according to this embodiment includes a stator 2, a rotor 3 arranged rotatably relative to the stator 2, and a shaft 4 fixed to the rotor 3. The stator 2 and the rotor 3 are arranged to be spaced apart in the axial direction of the shaft 4.

[0028] [Stator, Stator Core] Fig. 2 is a schematic diagram showing a stator according to an embodiment. As shown in Figs. 1 and 2, the stator 2 according to this embodiment is a stator for an axial gap motor 1. The stator 2 includes a stator core 5 having a plurality of core pieces 7, and windings 6 wound around each of the plurality of core pieces 7. The stator core 5 is the portion of the stator 2 excluding the windings 6. A shaft hole 8 through which the shaft 4 is inserted is formed in the center of the stator core 5.

[0029] [Core Piece] Fig. 3 is a perspective view showing a core piece according to the embodiment. Fig. 4 is a perspective view showing a core piece according to the embodiment. Fig. 5 is a front view showing a core piece according to the embodiment. Fig. 6 is a bottom view showing a core piece according to the embodiment. Fig. 7 is a cross-sectional view taken along line VII-VII shown in Fig. 6. As shown in Figs. 3 to 7, the core piece 7 according to this embodiment is a core piece of the stator core 5 of the axial gap motor 1. In other words, the core piece 7 is a part that constitutes a part of the stator core 5 of the axial gap motor 1.

[0030] The core pieces 7 are compacts formed by pressing soft magnetic powder coated with an insulating material. Examples of the soft magnetic powder material include pure iron, iron-silicon, and iron-cobalt. The average particle size of the soft magnetic powder is, for example, 3 μm to 300 μm, 30 μm to 200 μm, or 50 μm to 150 μm. Examples of the insulating material include an insulating coating containing phosphoric acid, silicone, or the like. The average particle size of the soft magnetic powder is measured using a robot shifter (model number: RPS-205) manufactured by Seishin Enterprise Co., Ltd.

[0031] The core piece 7 includes a tooth portion 10 , a first flange portion 20 , and a second flange portion 30 .

[0032] The teeth 10 extend in the first direction D1 and have peripheral surfaces 11 around which the windings 6 (see FIG. 1 ) are wound. The teeth 10 extend in the first direction D1 in a columnar shape, and their side surfaces form the peripheral surfaces 11.

[0033] The first flange portion 20 is connected to one end of the tooth portion 10 in the first direction D1, and protrudes from the tooth portion 10 in a direction perpendicular to the first direction D1. Here, the direction perpendicular to the first direction D1 is referred to as the second direction D2, and the direction perpendicular to the first direction D1 and the second direction D2 is referred to as the third direction D3. The first flange portion 20 protrudes from the tooth portion 10 when viewed from the first direction D1. Furthermore, the first flange portion 20 protrudes from one end of the tooth portion 10 in the first direction D1 in directions along the second direction D2 and the third direction D3. The first flange 20 has a first outer surface 21, which is the surface opposite the second flange 30 in the first direction D1, a first inner surface 22, which is the surface on the second flange 30 side in the first direction D1, a first lower end face 23, which is an end face on one side in the second direction D2, a first upper end face 24, which is an end face opposite the first lower end face 23 in the second direction D2, a first front end face 25, which is an end face on one side in the third direction D3, and a first rear end face 26, which is an end face opposite the first front end face 25 in the third direction D3. The first flange 20 is formed, for example, in the shape of a rectangular plate. That is, the first flange 20 is formed, for example, in a rectangular shape when viewed from the front, which is the viewing direction as seen from the first direction D1.

[0034] The second flange 30 is connected to an end of the tooth 10 opposite the first flange 20 in the first direction D1, and protrudes from the tooth 10 in a direction perpendicular to the first direction D1. The second flange 30 protrudes from the tooth 10 when viewed from the first direction D1. The second flange 30 also protrudes in directions along the second direction D2 and the third direction D3 from an end of the tooth 10 opposite the first flange 20 in the first direction D1. The second flange 30 has a second outer surface 31 that is the surface opposite to the first flange 20 in the first direction D1, a second inner surface 32 that is the surface on the first flange 20 side in the first direction D1, a second lower end surface 33 that is an end surface on one side in the second direction D2, a second upper end surface 34 that is an end surface opposite to the second lower end surface 33 in the second direction D2, a second front end surface 35 that is an end surface on one side in the third direction D3, and a second rear end surface 36 that is an end surface opposite to the second front end surface 35 in the third direction D3. The orientation of the second lower end surface 33 relative to the second upper end surface 34 in the second direction D2 is the same as the orientation of the first lower end surface 23 relative to the first upper end surface 24 in the second direction D2. The orientation of the second front end surface 35 relative to the second rear end surface 36 in the third direction D3 is the same as the orientation of the first front end surface 25 relative to the first rear end surface 26 in the third direction D3. The second flange portion 30 is formed, for example, in the shape of a rectangular plate. That is, the second flange portion 30 is formed, for example, in the shape of a rectangle when viewed from the front, which is the viewing direction when viewed from the first direction D1.

[0035] The circumferential surface 11 of the tooth portion 10 has an inner circumferential portion 12, an outer circumferential portion 13, a first side circumferential portion 14, and a second side circumferential portion 15. The inner circumferential portion 12, the outer circumferential portion 13, the first side circumferential portion 14, and the second side circumferential portion 15 form the entire circumference of the circumferential surface 11.

[0036] The inner circumferential portion 12 is located on one side in the second direction D2. The side in the second direction D2 where the inner circumferential portion 12 is located refers to the side of the center of the stator core 5, that is, the side of the shaft hole 8 of the stator core 5. The inner circumferential portion 12 is formed, for example, in a planar shape and extends in directions along the first direction D1 and the third direction D3.

[0037] The outer peripheral portion 13 is located on the opposite side of the inner peripheral portion 12 in the second direction D2. The opposite side of the inner peripheral portion 12 in the second direction D2 where the outer peripheral portion 13 is located refers to the opposite side of the center of the stator core 5, i.e., the opposite side of the shaft hole 8 of the stator core 5. The outer peripheral portion 13 is formed, for example, in a planar shape and extends in directions along the first direction D1 and the third direction D3. The length of the outer peripheral portion 13 in the third direction D3 is longer than the length of the inner peripheral portion 12 in the third direction D3. The orientation of the outer peripheral portion 13 relative to the inner peripheral portion 12 in the second direction D2 is the same as the orientation of the second lower end surface 33 relative to the second upper end surface 34 in the second direction D2 and the orientation of the first lower end surface 23 relative to the first upper end surface 24 in the second direction D2.

[0038] The first side circumferential portion 14 and the second side circumferential portion 15 are connected to the inner circumferential portion 12 and the outer circumferential portion 13 so as to face each other. That is, the first side circumferential portion 14 is connected to one edge of the inner circumferential portion 12 in the third direction D3 and one edge of the outer circumferential portion 13 in the third direction D3. The second side circumferential portion 15 is connected to an edge of the inner circumferential portion 12 opposite to the first side circumferential portion 14 in the third direction D3 and an edge of the outer circumferential portion 13 opposite to the first side circumferential portion 14 in the third direction D3.

[0039] The first side circumferential portion 14 has a first inner peripheral end portion 14a, a first outer peripheral end portion 14b, and a first central peripheral portion 14c. The first inner peripheral end portion 14a is the end portion of the first side circumferential portion 14 on the inner peripheral portion 12 side. The first outer peripheral end portion 14b is the end portion of the first side circumferential portion 14 on the outer peripheral portion 13 side. The first central peripheral portion 14c is disposed between the first inner peripheral end portion 14a and the first outer peripheral end portion 14b, and is a portion connected to the first inner peripheral end portion 14a and the first outer peripheral end portion 14b.

[0040] The second side circumferential portion 15 has a second inner peripheral end portion 15a, a second outer peripheral end portion 15b, and a second central peripheral portion 15c. The second inner peripheral end portion 15a is the end portion of the second side circumferential portion 15 on the inner peripheral portion 12 side. The second outer peripheral end portion 15b is the end portion of the second side circumferential portion 15 on the outer peripheral portion 13 side. The second central peripheral portion 15c is disposed between the second inner peripheral end portion 15a and the second outer peripheral end portion 15b, and is a portion connected to the second inner peripheral end portion 15a and the second outer peripheral end portion 15b.

[0041] The first inner peripheral side end portion 14 a and the second inner peripheral side end portion 15 a are not formed parallel to each other, but are formed so as to approach each other as they approach the inner peripheral portion 12 .

[0042] The first inner peripheral end 14a extends toward the second inner peripheral end 15a as it approaches the inner peripheral portion 12. The first inner peripheral end 14a may be a curved surface that curves toward the second inner peripheral end 15a, or may be an inclined surface that slopes toward the second inner peripheral portion 15a. That is, the first inner peripheral end 14a may be formed as a curved surface that curves toward the second inner peripheral end 15a, so that it extends toward the second inner peripheral end 15a as it approaches the inner peripheral portion 12. Alternatively, the first inner peripheral end 14a may be formed as an inclined surface that slopes toward the second inner peripheral end 15a with respect to the second direction D2, so that it extends toward the second inner peripheral end 15a as it approaches the inner peripheral portion 12. When the first inner peripheral end 14a is a curved surface, the first inner peripheral end 14a may be formed, for example, in an arc shape. The drawings show an example in which the first inner peripheral end 14a is formed in an arc shape.

[0043] The second inner peripheral end 15a extends toward the first inner peripheral end 14a as it approaches the inner peripheral portion 12. The second inner peripheral end 15a may be a curved surface that curves toward the first inner peripheral end 14a, or may be an inclined surface that slopes toward the first inner peripheral end 14a. That is, the second inner peripheral end 15a may be formed as a curved surface that curves toward the first inner peripheral end 14a, so that it extends toward the first inner peripheral end 14a as it approaches the inner peripheral portion 12. Alternatively, the second inner peripheral end 15a may be formed as an inclined surface that slopes toward the first inner peripheral end 14a with respect to the second direction D2, so that it extends toward the first inner peripheral end 14a as it approaches the inner peripheral portion 12. When the second inner peripheral end 15a is a curved surface, the second inner peripheral end 15a may be formed, for example, in an arc shape. In the drawings, as an example, the second inner peripheral end portion 15a is shown to be formed in an arc shape.

[0044] The first outer peripheral end portion 14b and the second outer peripheral end portion 15b extend in the first direction D1 and the second direction D2, respectively, and are formed parallel to each other, i.e., the first outer peripheral end portion 14b and the second outer peripheral end portion 15b are parallel surfaces.

[0045] The first central side peripheral portion 14 c and the second central side peripheral portion 15 c are not formed parallel to each other, but are formed so as to approach each other as they approach the inner peripheral portion 12 .

[0046] The first central circumferential portion 14c approaches the second central circumferential portion 15c as it approaches the inner circumferential portion 12. The first central circumferential portion 14c is, for example, an inclined surface that inclines toward the second central circumferential portion 15c with respect to the second direction D2 as it approaches the inner circumferential portion 12. Note that the first inner circumferential end portion 14a and the first central circumferential portion 14c may be inclined surfaces that incline at the same angle with respect to the second direction D2.

[0047] The second central circumferential portion 15c is inclined toward the first central circumferential portion 14c as it approaches the inner circumferential portion 12. The second central circumferential portion 15c is, for example, an inclined surface that is inclined toward the first central circumferential portion 14c with respect to the second direction D2 as it approaches the inner circumferential portion 12. Note that the second inner circumferential end portion 15a and the second central circumferential portion 15c may be inclined surfaces that are inclined at the same angle with respect to the second direction D2.

[0048] The end of tooth portion 10 on the first flange 20 side gradually widens as it reaches first flange 20. That is, the connection portion between tooth portion 10 and first flange 20 is formed in a curved shape. The end of tooth portion 10 on the second flange 30 side gradually widens as it reaches second flange 30. That is, the connection portion between tooth portion 10 and second flange 30 is formed in a curved shape.

[0049] As described above, in the core laminations 7 according to this embodiment, the circumferential surfaces 11 of the teeth 10 around which the windings 6 are wound have an inner circumferential portion 12, an outer circumferential portion 13, a first side circumferential portion 14, and a second side circumferential portion 15, and the first inner circumferential end portion 14a, which is the end of the first side circumferential portion 14 facing the inner circumferential portion 12, approaches the inner circumferential portion 12 toward the second inner circumferential end portion 15a, which is the end of the second side circumferential portion 15 facing the inner circumferential portion 12. Therefore, when the windings 6 are wound around the circumferential surfaces 11 of the teeth 10, the windings 6 can be easily aligned along the first inner circumferential end portion 14a and the inner circumferential portion 12. This makes it possible to suppress floating of the windings 6 from the teeth 10 near the connection between the first inner circumferential end portion 14a and the inner circumferential portion 12, thereby increasing the magnetic flux density.

[0050] Furthermore, in this core piece 7, the first inner peripheral side end portion 14a is a curved surface that curves toward the second inner peripheral side end portion 15a, making it easier to align the winding 6 with the first inner peripheral side end portion 14a and the inner peripheral portion 12.

[0051] Furthermore, in this core piece 7, the first inner peripheral side end portion 14a is an inclined surface that slopes toward the second inner peripheral side end portion 15a, making it possible to easily form the first inner peripheral side end portion 14a.

[0052] Furthermore, in this core piece 7, the second inner peripheral end portion 15a is directed toward the first inner peripheral end portion 14a as it approaches the inner peripheral portion 12, so that when the winding 6 is wound around the peripheral surface 11 of the tooth portion 10, the winding 6 can be easily aligned along the second inner peripheral end portion 15a and the inner peripheral portion 12. This makes it possible to suppress floating of the winding 6 from the tooth portion 10 near the connection portion between the second inner peripheral end portion 15a and the inner peripheral portion 12, thereby further increasing the magnetic flux density.

[0053] Furthermore, in this core piece 7, the second inner peripheral side end portion 15a is a curved surface that curves toward the first inner peripheral side end portion 14a, making it easier to align the winding 6 with the second inner peripheral side end portion 15a and the inner peripheral portion 12.

[0054] Furthermore, in this core piece 7, the second inner peripheral side end portion 15a is an inclined surface inclined toward the first inner peripheral side end portion 14a, so that the second inner peripheral side end portion 15a can be easily formed.

[0055] The stator core 5 according to this embodiment includes the above-described core pieces 7, and therefore can increase the magnetic flux density.

[0056] The stator 2 according to this embodiment has the above-described stator core 5, and therefore can increase the magnetic flux density.

[0057] The axial gap motor 1 according to this embodiment has the stator 2 described above, and therefore can increase the magnetic flux density.

[0058] [Core Piece Manufacturing Apparatus of First Embodiment] Next, a core piece manufacturing apparatus according to First Embodiment will be described. The core piece manufacturing apparatus is a powder compaction apparatus for manufacturing the core pieces 7.

[0059] Figure 8 is an exploded perspective view showing a core piece manufacturing apparatus according to the first embodiment. Figure 9 is a front view showing a core piece manufacturing apparatus according to the first embodiment. Figure 10 is a side view showing a core piece manufacturing apparatus according to the first embodiment. As shown in Figures 8 to 10, the core piece manufacturing apparatus 100 according to this embodiment includes a die 110 having a forming hole 111, an upper punch 120 inserted into the forming hole 111 from above U, a first lower punch 130 inserted into the forming hole 111 from below D, and a second lower punch 140 inserted into the forming hole 111 from below D.

[0060] Fig. 11 is a plan view showing a portion of the die. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11. Fig. 13 is a cross-sectional view taken along line XIII-XIII in Fig. 11. As shown in Figs. 8 to 11, the die 110 is a mold for powder compacting the core pieces 7. The die 110 is formed with a molding hole 111 for forming the core pieces 7. The molding hole 111 penetrates the die 110 in the up-down direction UD. In this embodiment, the molding hole 111 has the same cross section throughout the entire area in the up-down direction UD.

[0061] The forming hole 111 is composed of a tooth space 112 for forming the tooth portion 10 of the core piece 7, a first flange space 113 for forming the first flange portion 20 of the core piece 7, a second flange space 114 for forming the second flange portion 30 of the core piece 7, and a first punch space 115 and a second punch space 116 adjacent to the tooth space 112, the first flange space 113, and the second flange space 114. Each of the tooth space 112, the first flange space 113, the second flange space 114, the first punch space 115, and the second punch space 116 penetrates the die 110 in the up-down direction UD and has the same cross section throughout the up-down direction UD.

[0062] Here, directions perpendicular to each other in the horizontal direction are defined as a first horizontal direction D11 and a second horizontal direction D12. The first flange space 113 and the second flange space 114 are arranged to face each other in the first horizontal direction D11. The tooth space 112 is arranged in the center in the second horizontal direction D12, between the first flange space 113 and the second flange space 114 in the first horizontal direction D11. The first punch space 115 is arranged on one side of the tooth space 112 in the second horizontal direction D12, between the first flange space 113 and the second flange space 114 in the first horizontal direction D11. The second punch space 116 is arranged on the opposite side of the tooth space 112 from the first punch space 115 in the second horizontal direction D12, between the first flange space 113 and the second flange space 114 in the first horizontal direction D11.

[0063] Figure 14 is a perspective view showing an upper punch. As shown in Figures 8 to 14, the upper punch 120 is a punch that is inserted into the forming hole 111 from above U. The upper punch 120 is disposed above U of the forming hole 111 and is movable in the up-down direction UD. The upper punch 120 can be inserted into and removed from the forming hole 111 from above U of the die 110.

[0064] The upper punch 120 has an upper pressing portion for teeth 121 arranged above the tooth space 112 of the forming hole 111 in the U-shaped portion, a first upper pressing portion for first flange 122 arranged above the U-shaped portion space 113 of the forming hole 111, and a second upper pressing portion for second flange 123 arranged above the U-shaped portion space 114 of the forming hole 111. The portion between the first upper pressing portion for first flange 122 and the second upper pressing portion 123 other than the upper pressing portion for teeth 121 is cut out so that the upper punch 120 cannot be inserted into the first punch space 115 and the second punch space 116.

[0065] A tooth upper pressing surface 124 is formed on the lower surface of the tooth upper pressing portion 121, which forms the tooth portion 10 of the core piece 7 between it and the first lower punch 130. A first flange upper pressing surface 125 is formed on the lower surface of the first flange upper pressing surface 125, which forms the first flange portion 20 of the core piece 7 between it and the second lower punch 140. A second flange upper pressing surface 126 is formed on the lower surface of the second flange upper pressing portion 123, which forms the second flange portion 30 of the core piece 7 between it and the second lower punch 140.

[0066] The upper pressing surface 124 for teeth is formed by a part of the lower surface of the upper punch 120, and is inserted into the space 112 for teeth of the forming hole 111. The upper pressing surface 124 for teeth has a shape corresponding to the outer circumferential portion 13 of the tooth portion 10.

[0067] The first flange upper pressing surface 125 is formed by a part of the lower surface of the upper punch 120, and is inserted into the first flange space 113 of the forming hole 111. The first flange upper pressing surface 125 has a shape corresponding to the first upper end surface 24 of the first flange 20. The first flange upper pressing surface 125 is located above the tooth upper pressing surface 124 in the up-down direction UD.

[0068] The second flange upper pressing surface 126 is formed by a part of the lower surface of the upper punch 120, and is inserted into the second flange space 114 of the forming hole 111. The second flange upper pressing surface 126 has a shape corresponding to the second upper end surface 34 of the second flange 30. The second flange upper pressing surface 126 is located above the tooth upper pressing surface 124 in the up-down direction UD.

[0069] Figure 15 is a perspective view of the first lower punch. Figure 16 is a perspective view of the first lower punch. Figure 17 is a front view of the first lower punch. As shown in Figures 8 to 13 and 15 to 17, the first lower punch 130 is a punch that is inserted into the forming hole 111 from below D. The first lower punch 130 is disposed below D of the forming hole 111 and is movable in the up-down direction UD. The first lower punch 130 is insertable into and removable from the forming hole 111 from below D of the die 110.

[0070] The first lower punch 130 has a first mold portion 131 arranged below D of the first punch space 115 of the forming hole 111, a second mold portion 132 arranged below D of the second punch space 116 of the forming hole 111, and a lower tooth pressing portion 133 arranged below D of the tooth space 112 of the forming hole 111.

[0071] The first lower punch 130 is formed in a U-shape that is open upward toward the U. The first mold portion 131 and the second mold portion 132 face each other in the second horizontal direction D12 and are arranged to be spaced apart in the second horizontal direction D12. The lower tooth pressing portion 133 is arranged between a lower portion of the first mold portion 131 and a lower portion of the second mold portion 132. In other words, the first mold portion 131 and the second mold portion 132 extend further upward toward the U than the lower tooth pressing portion 133. A space that is open upward toward the U and in the first horizontal direction D11 is formed between the first mold portion 131, the second mold portion 132, and the lower tooth pressing portion 133.

[0072] A tooth lower pressing surface 134 is formed on the upper surface of the tooth lower pressing portion 133 , which forms the tooth portion 10 of the core piece 7 between itself and the upper punch 120 .

[0073] The lower tooth pressing surface 134 is formed by a portion of the upper surface of the first lower punch 130 and is inserted into the tooth space 112 of the forming hole 111. The lower tooth pressing surface 134 has a bottom surface 135 shaped to correspond to the inner periphery 12 of the tooth portion 10, a first side surface 136 shaped to correspond to the first side periphery 14 of the tooth portion 10, and a second side surface 137 shaped to correspond to the second side periphery 15 of the tooth portion 10. The end of the first side surface 136 on the bottom surface 135 side forms a first bottom surface 136a shaped to correspond to the first inner periphery end 14a of the first side periphery 14. The end of the second side surface 137 on the bottom surface 135 side forms a second bottom surface 137a shaped to correspond to the second inner periphery end 15a of the second side periphery 15.

[0074] Specifically, the bottom surface 135 is formed, for example, in a planar shape and extends in a direction along the first horizontal direction D11 and the second horizontal direction D12.

[0075] The first side bottom surfaces 136 a and 136 a are not formed parallel to each other, but are formed so as to approach each other as they approach the bottom surface 135 .

[0076] The first-side bottom surface 136a extends toward the second-side bottom surface 137a as it approaches the bottom surface 135. The first-side bottom surface 136a may be a curved surface that curves toward the second-side bottom surface 137a, or may be an inclined surface that slopes toward the second-side bottom surface 137a. That is, the first-side bottom surface 136a may be formed as a curved surface that curves toward the second-side bottom surface 137a, so that it slopes toward the bottom surface 135. Alternatively, the first-side bottom surface 136a may be formed as an inclined surface that slopes toward the second-side bottom surface 137a with respect to the up-down direction UD, so that it slopes toward the second-side bottom surface 137a as it approaches the bottom surface 135. When the first-side bottom surface 136a is a curved surface, the first-side bottom surface 136a may be formed, for example, in an arc shape. The drawings show, as an example, a case where the first-side bottom surface 136a is formed in an arc shape.

[0077] The second-side bottom surface 137a extends toward the first-side bottom surface 136a as it approaches the bottom surface 135. The second-side bottom surface 137a may be a curved surface that curves toward the first-side bottom surface 136a, or may be an inclined surface that slopes toward the first-side bottom surface 136a. That is, the second-side bottom surface 137a may be formed as a curved surface that curves toward the first-side bottom surface 136a, so that it slopes toward the bottom surface 135. Alternatively, the second-side bottom surface 137a may be formed as an inclined surface that slopes toward the first-side bottom surface 136a with respect to the up-down direction UD, so that it slopes toward the first-side bottom surface 136a as it approaches the bottom surface 135. When the second-side bottom surface 137a is a curved surface, the second-side bottom surface 137a may be formed, for example, in an arc shape. The drawings show, as an example, a case where the second-side bottom surface 137a is formed in an arc shape.

[0078] A portion 136b of the first side surface 136 other than the first bottom surface 136a forms a first central circumferential portion 14c of the tooth portion 10. A portion 137b of the second side surface 137 other than the second bottom surface 137a forms a second central circumferential portion 15c of the tooth portion 10. The portion 136b of the first side surface 136 and the portion 137b of the second side surface 137 are not formed parallel to each other, but are formed so as to approach each other toward the bottom surface 135.

[0079] The inner surface 131a of the first mold portion 131 facing the second mold portion 132 forms the first outer peripheral end portion 14b of the tooth portion 10. The inner surface 132a of the second mold portion 132 facing the first mold portion 131 forms the second outer peripheral end portion 15b of the tooth portion 10. The inner surface 131a of the first mold portion 131 and the inner surface 132a of the second mold portion 132 are formed parallel to each other and face each other in the second horizontal direction D12. In other words, the inner surface 131a of the first mold portion 131 and the inner surface 132a of the second mold portion 132 are parallel to each other.

[0080] One surface of the first lower punch 130 in the first horizontal direction D11 serves as a first flange inner pressing surface 138 that forms the first inner surface 22 of the first flange 20 of the core piece 7. The surface of the first lower punch 130 opposite to the first flange inner pressing surface 138 in the first horizontal direction D11 serves as a second flange inner pressing surface 139 that forms the second inner surface 32 of the second flange 30 of the core piece 7.

[0081] The first flange inner pressing surface 138 is formed by a part of the surface on one side in the first horizontal direction D11 of the first mold portion 131, the second mold portion 132, and the tooth lower pressing portion 133, and is inserted into the boundary between the tooth space 112, the first punch space 115, and the second punch space 116 of the forming hole 111 and the first flange space 113. The first flange inner pressing surface 138 has a shape corresponding to the first inner surface 22 of the first flange 20.

[0082] The second flange inner pressing surface 139 is formed by a part of the surface of the first mold portion 131, the second mold portion 132, and the tooth lower pressing portion 133 opposite to the first flange inner pressing surface 138 in the first horizontal direction D11, and is inserted into the boundary between the tooth space 112, the first punch space 115, and the second punch space 116 of the forming hole 111 and the second flange space 114. The second flange inner pressing surface 139 has a shape corresponding to the second inner surface 32 of the second flange 30.

[0083] 8 to 13, the second lower punch 140 is a punch that is inserted into the forming hole 111 from below D. The second lower punch 140 is disposed below D of the forming hole 111 and is movable in the up-down direction UD. The second lower punch 140 is insertable into and removable from the forming hole 111 from below D of the die 110.

[0084] The second lower punch 140 has a lower pressing portion 141 for the first flange portion arranged below D of the space 113 for the first flange portion of the forming hole 111, and a lower pressing portion 142 for the second flange portion arranged below D of the space 114 for the second flange portion of the forming hole 111.

[0085] The second lower punch 140 is formed in a U-shape that is open upward toward the U. The first flange lower pressing portion 141 and the second flange lower pressing portion 142 face each other in the first horizontal direction D11 and are arranged to be spaced apart in the first horizontal direction D11. The second lower punch 140 has a portion between the first flange lower pressing portion 141 and the second flange lower pressing portion 142 cut out so that the second lower punch 140 cannot be inserted into the tooth space 112, the first punch space 115, or the second punch space 116. In other words, a space that is open upward toward the U and in the second horizontal direction D12 is formed between the first flange lower pressing portion 141 and the second flange lower pressing portion 142.

[0086] A first flange lower pressing surface 143 is formed on the upper surface of the first flange lower pressing portion 141, which forms the first flange 20 of the core piece 7 between itself and the upper punch 120. A second flange lower pressing surface 144 is formed on the upper surface of the second flange lower pressing portion 142, which forms the second flange 30 of the core piece 7 between itself and the upper punch 120.

[0087] The first flange lower pressing surface 143 is formed by the upper surface of the first flange lower pressing portion 141, and is inserted into the first flange space 113 of the molding hole 111. The first flange lower pressing surface 143 has a shape corresponding to the first lower end surface 23 of the first flange 20.

[0088] The second flange lower pressing surface 144 is formed by the upper surface of the second flange lower pressing portion 142, and is inserted into the second flange space 114 of the molding hole 111. The second flange lower pressing surface 144 has a shape corresponding to the second lower end surface 33 of the second flange 30.

[0089] As described above, in the core piece manufacturing apparatus 100 according to this embodiment, the upper punch 120 has the upper pressing surface 124 for teeth that forms the tooth portion 10 of the core piece 7 between itself and the first lower punch 130, and the upper pressing surface 125 for first flange portion and the upper pressing surface 126 for second flange portion that form the first flange portion 20 and the second flange portion 30 of the core piece 7 between itself and the second lower punch 140, the first lower punch 130 has the lower pressing surface 134 for teeth that forms the tooth portion 10 between itself and the upper punch 120, and the second lower punch 140 has the lower pressing surface 134 for teeth that forms the first flange portion 20 between itself and the upper punch 120, 20 and second flange portion 30, and upper punch 120 has first flange portion lower pressing surface 143 and second flange portion lower pressing surface 144, and upper punch 120 has teeth upper pressing surface 124 shaped to correspond to outer periphery 13 of teeth portion 10, and first lower punch 130 has teeth lower pressing surface 134 which has bottom surface 135 shaped to correspond to inner periphery 12 of teeth portion 10, first bottom surface 136a shaped to correspond to first inner periphery end 14a of teeth portion 10, and second bottom surface 137a shaped to correspond to second inner periphery end 15a of teeth portion 10. Therefore, the above-described core pieces 7 can be compacted by inserting the first lower punch 130 and the second lower punch 140 into the molding hole 111 of the die 110, supplying the soft magnetic powder 9 coated with an insulating material into the molding hole 111 from above, inserting the upper punch 120 into the molding hole 111, and pressing the soft magnetic powder 9 between the upper punch 120 and the first lower punch 130 and the second lower punch 140. This makes it possible to manufacture core pieces 7 that can have an increased magnetic flux density.

[0090] [Core Piece Manufacturing Method of First Embodiment] Next, a core piece manufacturing method according to the first embodiment will be described. The core piece manufacturing method according to the first embodiment is a method for manufacturing the core piece 7 described above using the core piece manufacturing apparatus 100 described above.

[0091] The core piece manufacturing method includes a preparation process, a lower punch insertion process performed after the preparation process, a powder supply process performed after the lower punch insertion process, a pressing process performed after the powder supply process, and an extraction process performed after the pressing process.

[0092] In the preparation step, the above-described core piece manufacturing device 100 and soft magnetic powder coated with an insulating material are prepared.

[0093] 18 and 19 are cross-sectional views showing the lower punch inserting step. As shown in Fig. 18 and 19, in the lower punch inserting step, the first lower punch 130 and the second lower punch 140 are inserted into the forming hole 111 of the die 110.

[0094] Specifically, in the lower punch insertion step, the first mold portion 131 of the first lower punch 130 is inserted into the first punch space 115 of the forming hole 111, the second mold portion 132 of the first lower punch 130 is inserted into the second punch space 116 of the forming hole 111, and the lower tooth pressing portion 133 of the first lower punch 130 is inserted into the tooth space 112 of the forming hole 111. Then, the first mold portion 131 is placed in the first punch space 115, the second mold portion 132 is placed in the second punch space 116, and the lower tooth pressing surface 134 of the lower tooth pressing portion 133 is placed in the tooth space 112. As a result, the bottom of the tooth space 112 is formed by the tooth lower pressing surface 134, the area near the tooth lower pressing surface 134 in the first punch space 115 is blocked by the first mold portion 131, and the area near the tooth lower pressing surface 134 in the second punch space 116 is blocked by the second mold portion 132.

[0095] Furthermore, in the lower punch insertion step, the first flange lower pressing portion 141 of the second lower punch 140 is inserted into the first flange space 113 of the forming hole 111, and the second flange lower pressing portion 142 of the second lower punch 140 is inserted into the second flange space 114 of the forming hole 111. Then, the first flange lower pressing surface 143 of the second lower punch 140 is placed in the first flange space 113 of the forming hole 111, and the second flange lower pressing surface 144 of the second lower punch 140 is placed in the second flange space 114 of the forming hole 111. As a result, the first flange lower pressing surface 143 forms the bottom of the first flange space 113, and the second flange lower pressing surface 144 forms the bottom of the second flange space 114.

[0096] At this time, the positions of the first lower punch 130 and the second lower punch 140 in the up-down direction UD are set so that the first flange portion lower pressing surface 143 and the second flange portion lower pressing surface 144 are located at a position D below the tooth portion lower pressing surface 134. As a result, in the forming hole 111, a space that is open upward U is formed by the die 110, the first flange portion lower pressing surface 143 and the second flange portion lower pressing surface 144 of the second lower punch 140, and the inner surface 131 a, inner surface 132 a, tooth portion lower pressing surface 134, first flange portion inner pressing surface 138, and second flange portion inner pressing surface 139 of the first lower punch 130.

[0097] 20 and 21 are cross-sectional views showing the powder supplying step. As shown in FIGS. 18 to 21 , in the powder supplying step, soft magnetic powder 9 coated with an insulating material is supplied from above U into a molding hole 111. The soft magnetic powder 9 supplied into the molding hole 111 is supplied into a space open to the above U, which is formed by the die 110, the first flange portion lower pressing surface 143 and the second flange portion lower pressing surface 144 of the second lower punch 140, and the inner surface 131 a, the inner surface 132 a, the tooth portion lower pressing surface 134, the first flange portion inner pressing surface 138, and the second flange portion inner pressing surface 139 of the first lower punch 130.

[0098] 22 and 23 are cross-sectional views showing the pressing process. As shown in Fig. 20 to Fig. 23, in the pressing process, an upper punch 120 is inserted into a molding hole 111 of a die 110, and the soft magnetic powder 9 supplied to the molding hole 111 is pressed by the upper punch 120, the first lower punch 130, and the second lower punch 140 to form a core piece 7 formed by pressing the soft magnetic powder 9.

[0099] Specifically, in the pressing process, the upper punch 120 is moved (lowered) downward D, and the upper pressing portion 121 for the teeth of the upper punch 120 is pressed into the space 112 for the teeth of the forming hole 111, the upper pressing portion 122 for the first flange portion of the upper punch 120 is pressed into the space 113 for the first flange portion of the forming hole 111, and the upper pressing portion 123 for the second flange portion of the upper punch 120 is pressed into the space 114 for the second flange portion of the forming hole 111. Furthermore, the first lower punch 130 is moved (raised) upward U, the first mold portion 131 of the first lower punch 130 is further inserted into the first punch space 115 of the forming hole 111, the second mold portion 132 of the first lower punch 130 is further inserted into the second punch space 116 of the forming hole 111, and the lower tooth pressing portion 133 of the first lower punch 130 is pressed into the tooth space 112 of the forming hole 111. Note that the amount of movement of the second lower punch 140 upward U is set to be greater than the amount of movement of the first lower punch 130 upward U.

[0100] As a result, the soft magnetic powder 9 supplied to the forming hole 111 is pressed by the upper punch 120, the first lower punch 130, and the second lower punch 140, thereby being molded into the core piece 7. That is, the soft magnetic powder 9 is pressed by the upper tooth pressing surface 124 of the upper punch 120 and the lower tooth pressing surface 134 of the first lower punch 130, thereby being molded into the tooth portion 10 of the core piece 7. Furthermore, the soft magnetic powder 9 is pressed by the first flange upper pressing surface 125 of the upper punch 120 and the first flange lower pressing surface 143 of the second lower punch 140, thereby being molded into the first flange portion 20 of the core piece 7. Furthermore, the soft magnetic powder 9 is pressed by the second flange upper pressing surface 126 of the upper punch 120 and the second flange lower pressing surface 144 of the second lower punch 140, thereby being molded into the second flange 30 of the core piece 7. The core piece 7 is formed by pressing the soft magnetic powder 9, that is, a compact of the soft magnetic powder 9.

[0101] 24 and 25 are cross-sectional views showing the ejection step. As shown in FIGS. 22 to 25, in the ejection step, the core piece 7 is ejected from the molding hole 111.

[0102] Specifically, in the ejection process, the upper punch 120 is moved (raised) upward U so that the upper punch 120 is ejected from the forming hole 111 and positioned above the die 110. The second lower punch 140 is also moved (raised) upward U so that the first flange lower pressing surface 143 and the second flange lower pressing surface 144 are flush with the upper surface of the die 110 or positioned higher than the die 110. As a result, the first flange 20 and the second flange 30 of the core piece 7 are pushed up by the first flange lower pressing portion 141 and the second flange lower pressing portion 142, and the core piece 7 is ejected from the first lower punch 130 and the forming hole 111. The core piece 7 is then removed from the core piece manufacturing apparatus 100, completing the manufacturing of the core piece 7.

[0103] As described above, in the core piece manufacturing method according to this embodiment, the first lower punch 130 and the second lower punch 140 are inserted into the forming hole 111, soft magnetic powder 9 coated with an insulating material is supplied to the forming hole 111 from above, the upper punch 120 is inserted into the forming hole 111, and the soft magnetic powder 9 supplied to the forming hole 111 is pressed by the upper punch 120, the first lower punch 130, and the second lower punch 140, thereby compacting the above-mentioned core pieces 7. After the core pieces 7 have been compacted, they are removed from the forming hole 111, thereby producing core pieces 7 with increased magnetic flux density.

[0104] In addition, in this core piece manufacturing apparatus, after the core piece 7 has been powder-molded, the upper punch 120 and the second lower punch 140 can be moved upward to easily remove the core piece 7 from the molding hole 111.

[0105] [Core Piece Manufacturing Apparatus of Second Embodiment] Next, a core piece manufacturing apparatus according to a second embodiment will be described. The core piece manufacturing apparatus according to the second embodiment is basically the same as the core piece manufacturing apparatus according to the first embodiment, and differs from the core piece manufacturing apparatus according to the first embodiment only in that the first lower punch is divided into a first main lower punch and a first auxiliary lower punch. Therefore, only the differences from the core piece manufacturing apparatus according to the first embodiment will be described below, and descriptions of the same aspects as those of the core piece manufacturing apparatus according to the first embodiment will be omitted.

[0106] Figure 26 is an exploded perspective view showing a core piece manufacturing apparatus according to a second embodiment. Figure 27 is a front view showing a core piece manufacturing apparatus according to the second embodiment. Figure 28 is a side view showing a core piece manufacturing apparatus according to the second embodiment. As shown in Figures 26 to 28, a core piece manufacturing apparatus 200 according to this embodiment includes a die 110 having a forming hole 111, an upper punch 120 inserted into the forming hole 111 from above U, a first lower punch 230 inserted into the forming hole 111 from below D, and a second lower punch 140 inserted into the forming hole 111 from below D.

[0107] Similar to the first lower punch 130 of the first embodiment (see FIGS. 15 to 17), the first lower punch 230 has a first mold portion 131, a second mold portion 132, and a lower tooth pressing portion 133. A lower tooth pressing surface 134 is formed on the upper surface of the lower tooth pressing portion 133. The lower tooth pressing surface 134 has a bottom surface 135, a first side surface 136 (first side bottom surface 136a and portion 136b), and a second side surface 137 (second side bottom surface 137a and portion 137b).

[0108] The first lower punch 230 has a first main lower punch 230A and a first sub-lower punch 230B that is movable in the up-down direction UD relative to the first main lower punch 230A.

[0109] The first main lower punch 230A has a first mold portion 131, a second mold portion 132, and a portion of the lower tooth pressing portion 133. The first main lower punch 230A has a slit extending in the up-down direction UD, into which the first sub-lower punch 230B is inserted so as to be movable in the up-down direction UD. The slit of the first main lower punch 230A is formed in the lower tooth pressing portion 133. The first main lower punch 230A has a portion 134A of the lower tooth pressing surface 134. The portion 134A of the lower tooth pressing surface 134 is composed of, for example, a portion of the bottom surface 135, a first side surface 136 (first side bottom surface 136a and portion 136b), and a second side surface 137 (second side bottom surface 137a and portion 137b).

[0110] The first auxiliary lower punch 230B has a remaining portion of the lower tooth pressing portion 133. The first auxiliary lower punch 230B is inserted into a slit formed in the first main lower punch 230A so as to be movable in the up-down direction UD relative to the first main lower punch 230A. The first auxiliary lower punch 230B has a remaining portion 134B of the lower tooth pressing surface 134. The remaining portion 134B of the lower tooth pressing surface 134 is formed by, for example, a remaining portion of the bottom surface 135.

[0111] As described above, in the core piece manufacturing apparatus 200 according to this embodiment, the first lower punch 230 includes a first main lower punch 230A having a portion 134A of the lower tooth pressing surface 134, and a first auxiliary lower punch 230B having the remaining portion 134B of the lower tooth pressing surface 134 and movable in the up-down direction UD relative to the first main lower punch 230A. Therefore, after the core piece 7 has been powder-compressed, the first auxiliary lower punch 230B can be moved upward in the U direction relative to the first main lower punch 230A, thereby easily extracting the core piece 7 from the first main lower punch 230A.

[0112] Furthermore, in this core piece manufacturing apparatus 200, the first main lower punch 230A has the first side surface 136 (first side bottom surface 136a and portion 136b) and second side surface 137 (second side bottom surface 137a and portion 137b) of the tooth lower pressing surface 134, and a portion of the bottom surface 135, and the first auxiliary lower punch 230B has the remaining portion of the bottom surface 135 of the tooth lower pressing surface 134. Therefore, after the core piece 7 has been powder-compressed, the first auxiliary lower punch 230B can be moved upward U relative to the first main lower punch 230A, thereby making it possible to easily extract the core piece 7 from the first main lower punch 230A.

[0113] [Core Piece Manufacturing Method of Second Embodiment] Next, a core piece manufacturing method of a second embodiment will be described. The core piece manufacturing method of the second embodiment is basically the same as the core piece manufacturing method of the first embodiment, but differs from the core piece manufacturing method of the first embodiment only in that the core piece 7 is manufactured using the core piece manufacturing apparatus 200 described above. For this reason, only the differences from the core piece manufacturing method of the first embodiment will be described below, and descriptions of the same aspects as the core piece manufacturing method of the first embodiment will be omitted.

[0114] The core piece manufacturing method includes a preparation process, a lower punch insertion process performed after the preparation process, a powder supply process performed after the lower punch insertion process, a pressing process performed after the powder supply process, and an extraction process performed after the pressing process.

[0115] In the preparation step, the above-described core piece manufacturing device 200 and soft magnetic powder coated with an insulating material are prepared.

[0116] 29 and 30 are cross-sectional views showing the lower punch inserting step. As shown in Fig. 29 and 30, in the lower punch inserting step, the first lower punch 230 and the second lower punch 140 are inserted into the forming hole 111 of the die 110.

[0117] Specifically, in the lower punch insertion step, a portion 134A of the lower tooth pressing surface 134 of the first main lower punch 230A and the remaining portion 134B of the lower tooth pressing surface 134 of the first auxiliary lower punch 230B are aligned, and the lower tooth pressing surface 134 of the first lower punch 230 is formed by the first main lower punch 230A and the first auxiliary lower punch 230B. Then, the first lower punch 230 (the first main lower punch 230A and the first auxiliary lower punch 230B) and the second lower punch 140 are inserted into the forming hole 111 of the die 110. Note that the formation of the lower tooth pressing surface 134 by the first main lower punch 230A and the first auxiliary lower punch 230B may be performed after the first main lower punch 230A and the first auxiliary lower punch 230B are inserted into the forming hole 111.

[0118] 31 and 32 are cross-sectional views showing the powder supplying step. As shown in Fig. 29 to Fig. 32, in the powder supplying step, soft magnetic powder 9 coated with an insulating material is supplied from above U into the molding hole 111.

[0119] 31 to 34 are cross-sectional views showing the pressing process. As shown in Fig. 31 to 34, in the pressing process, the upper punch 120 is inserted into the forming hole 111 of the die 110, and the soft magnetic powder supplied to the forming hole 111 is pressed by the upper punch 120, the first lower punch 230, and the second lower punch 140 to form the core piece 7 made of the pressed soft magnetic powder.

[0120] 35 and 36 are cross-sectional views showing the ejection step. As shown in FIGS. 33 to 36, in the ejection step, the core piece 7 is ejected from the molding hole 111.

[0121] Specifically, in the ejection step, the upper punch 120 is moved (raised) upward in the U direction so that the upper punch 120 is ejected from the forming hole 111 and positioned above the die 110. Also, the first sub-lower punch 230B is moved (raised) upward in the U direction relative to the first main lower punch 230A so that the remaining portion 134B of the lower teeth pressing surface 134 of the first sub-lower punch 230B is flush with the upper surface of the die 110 or positioned higher than the die 110. At this time, the first main lower punch 230A is not moved (raised) upward in the U direction, but the first main lower punch 230A may be moved (raised) upward in the U direction within a range that allows the first sub-lower punch 230B to be moved (raised) upward in the U direction relative to the first main lower punch 230A. As a result, the teeth 10 of the core piece 7 are pushed up by the first auxiliary lower punch 230B, and the core piece 7 is extracted from the first main lower punch 230A and the forming hole 111. In the extraction process, the second lower punch 140 may be moved (raised) upward U so that the first flange lower pressing surface 143 and the second flange lower pressing surface 144 are flush with the upper surface of the die 110 or positioned higher than the die 110. Thereafter, the core piece 7 is removed from the core piece manufacturing apparatus 200, thereby completing the manufacturing of the core piece 7.

[0122] As described above, in the core piece manufacturing method of this embodiment, after the core piece 7 is powder-compressed, the upper punch 120 is moved upward and the first auxiliary lower punch 230B is moved upward U relative to the first main lower punch 230A, thereby making it possible to easily extract the core piece 7 from the first main lower punch 230A and also to easily extract the core piece 7 from the molding hole 111.

[0123] The present disclosure is not limited to the above-described embodiments, and modifications can be made as appropriate without departing from the spirit of the present disclosure.

[0124] For example, in the above embodiment, the specific shape of the core piece was described, but the shape of the core piece may be changed as long as the first inner peripheral side end portion of the first side peripheral portion moves toward the second inner peripheral side end portion as it moves toward the inner peripheral portion.

[0125] For example, the second inner peripheral end of the tooth may extend in the first direction and the second direction similarly to the second outer peripheral end, rather than moving toward the first inner peripheral end as it approaches the inner peripheral portion. Also, the inner peripheral portion and the outer peripheral portion of the tooth may not extend in the first direction and the third direction.

[0126] For example, the first flange and the second flange do not have to be rectangular plate-shaped, and may be formed such that, in the first flange, the length of the first upper end face in the third direction is longer than the length of the first lower end face in the third direction, and the first front end face and the first rear end face approach each other toward the first lower end. Also, in the second flange, the length of the second upper end face in the third direction is longer than the length of the second lower end face in the third direction, and the second front end face and the second rear end face approach each other toward the second lower end. Furthermore, the first flange and the second flange may have the same shape or different shapes.

[0127] The present disclosure can be used as a core piece, a stator core, a stator, an axial gap motor, a core piece manufacturing device, and a core piece manufacturing method.

[0128] DESCRIPTION OF SYMBOLS 1...Axial gap motor, 2...Stator, 3...Rotor, 4...Shaft, 5...Stator core, 6...Winding, 7...Core piece, 8...Shaft hole, 9...Soft magnetic powder, 10...Teeth portion, 11...Circumferential surface, 12...Inner peripheral portion, 13...Outer peripheral portion, 14...First side peripheral portion, 14a...First inner peripheral end portion, 14b...First outer peripheral end portion, 14c...First central peripheral portion, 15...Second side peripheral portion, 15a...Second inner peripheral end portion, 15b...Second outer peripheral end portion, 15c...Second central peripheral portion, 20...First flange portion, 21...First outer surface, 22 ...first inner surface, 23...first lower end surface, 24...first upper end surface, 25...first front end surface, 26...first rear end surface, 30...second flange portion, 31...second outer surface, 32...second inner surface, 33...second lower end surface, 34...second upper end surface, 35...second front end surface, 36...second rear end surface, 100...core piece manufacturing apparatus, 110...die, 111...forming hole, 112...space for teeth, 113...space for first flange portion, 114...space for second flange portion, 115...space for first punch, 116...space for second punch, 120...upper punch, 121...upper push-in for teeth Pressing portion, 122...first flange portion upper pressing portion, 123...second flange portion upper pressing portion, 124...teeth upper pressing surface, 125...first flange portion upper pressing surface, 126...second flange portion upper pressing surface, 130...first lower punch, 131...first mold portion, 131a...inner surface, 132...second mold portion, 132a...inner surface, 133...teeth lower pressing portion, 134...teeth lower pressing surface, 135...bottom surface, 136...first side surface, 136a...first side bottom surface, 136b...portion, 137...second side surface, 137a...second side bottom surface, 137b...portion minutes, 138...inner pressing surface for first flange portion, 139...inner pressing surface for second flange portion, 140...second lower punch, 141...lower pressing portion for first flange portion, 142...lower pressing portion for second flange portion, 143...lower pressing surface for first flange portion, 144...lower pressing surface for second flange portion, 200...core piece manufacturing device, 230...first lower punch, 230A...first main lower punch, 230B...first auxiliary lower punch, D1...first direction, D2...second direction, D3...third direction, D11...first horizontal direction, D12...second horizontal direction, UD...upward direction, U...upward, D...downward.

Claims

1. A core piece of a stator core of an axial gap motor, which is made by pressing soft magnetic powder coated with an insulating material, a teeth portion extending in a first direction and having a circumferential surface around which a winding is wound; a first flange portion connected to one end of the tooth portion in the first direction and protruding from the tooth portion in a direction perpendicular to the first direction; a second flange portion connected to an end of the tooth portion opposite to the first flange portion in the first direction and protruding from the tooth portion in a direction perpendicular to the first direction, The peripheral surface of the tooth portion is an inner circumferential portion located on one side in a second direction perpendicular to the first direction; an outer circumferential portion located on the opposite side of the inner circumferential portion in the second direction; a first side circumferential portion and a second side circumferential portion connected to the inner circumferential portion and the outer circumferential portion, a first inner peripheral end portion, which is an end portion of the first side peripheral portion on the inner peripheral portion side, is directed toward a second inner peripheral end portion, which is an end portion of the second side peripheral portion on the inner peripheral portion side, as it approaches the inner peripheral portion; Core piece.

2. The first inner peripheral side end portion is a curved surface that curves toward the second inner peripheral side end portion. The core piece according to claim 1 .

3. The first inner peripheral side end portion is an inclined surface inclined toward the second inner peripheral side end portion, The core piece according to claim 1 .

4. The second inner peripheral side end portion is directed toward the first inner peripheral side end portion as it approaches the inner peripheral portion. The core piece according to claim 1 .

5. The second inner peripheral side end portion is a curved surface that curves toward the first inner peripheral side end portion. The core piece according to claim 4.

6. The second inner peripheral side end portion is an inclined surface inclined toward the first inner peripheral side end portion, The core piece according to claim 4.

7. A stator core of an axial gap motor, The core piece according to any one of claims 1 to 6 is provided. Stator core.

8. A stator of an axial gap motor, The stator core according to claim 7; a winding wound around the core pieces of the stator core, Stator.

9. A stator according to claim 8; a rotor rotatably disposed relative to the stator, Axial gap motor.

10. A core piece manufacturing apparatus for manufacturing the core piece according to any one of claims 1 to 6, a die having a forming hole; an upper punch inserted into the forming hole from above; a first lower punch inserted into the forming hole from below; a second lower punch inserted into the forming hole from below, the upper punch has a tooth upper pressing surface which forms the tooth portion of the core piece between itself and the first lower punch, and a first flange upper pressing surface and a second flange upper pressing surface which form the first flange portion and the second flange portion of the core piece between itself and the second lower punch, the first lower punch has a teeth lower pressing surface that forms the teeth portion between itself and the upper punch, the second lower punch has a first flange portion lower pressing surface and a second flange portion lower pressing surface which form the first flange portion and the second flange portion between itself and the upper punch, the upper pressing surface for teeth of the upper punch has a shape corresponding to the outer periphery of the tooth portion, The lower pressing surface for teeth of the first lower punch has a bottom surface shaped to correspond to the inner peripheral portion of the tooth portion, a first bottom surface shaped to correspond to the first inner peripheral side end portion of the tooth portion, and a second bottom surface shaped to correspond to the second inner peripheral side end portion of the tooth portion. Core piece manufacturing equipment.

11. the first lower punch includes a first main lower punch and a first sub-lower punch that is movable in a vertical direction relative to the first main lower punch, the first main lower punch has a part of the teeth lower pressing surface, The first sub-lower punch has a remaining portion of the lower pressing surface for teeth. The core piece manufacturing apparatus according to claim 10.

12. the first main lower punch has the first bottom surface of the teeth lower pressing surface and a part of the bottom surface, The first sub-lower punch has a remaining portion of the bottom surface of the teeth lower pressing surface. The core piece manufacturing apparatus according to claim 11.

13. A core piece manufacturing method for manufacturing a core piece of a stator core of an axial gap motor using the core piece manufacturing apparatus according to claim 10, a lower punch inserting step of inserting the first lower punch and the second lower punch into the forming hole of the die; a powder supplying step of supplying soft magnetic powder coated with an insulating material from above into the molding hole after the lower punch inserting step; a pressing step of inserting the upper punch into the molding hole after the powder supplying step, and pressing the soft magnetic powder supplied to the molding hole with the upper punch, the first lower punch, and the second lower punch to form a core piece obtained by pressing the soft magnetic powder; and a removal step of removing the core piece from the molding hole after the pressing step. Core piece manufacturing method.

14. In the ejection step, the upper punch and the second lower punch are moved upward. The method for manufacturing a core piece according to claim 13.

15. the first lower punch includes a first main lower punch having a portion of the lower pressing surface for teeth, and a first sub-lower punch having a remaining portion of the lower pressing surface for teeth and movable in a vertical direction relative to the first main lower punch, In the removing step, the upper punch is moved upward, and the first sub-lower punch is moved upward relative to the first main lower punch. The method for manufacturing a core piece according to claim 13.