Core piece, stator core, stator, and axial gap motor

Abstract

This core piece of a stator core for an axial gap motor is formed by pressing a soft magnetic powder covered with an insulating material and comprises: a tooth part that extends in a first direction and has a peripheral surface around which a winding is wound; a first brim part that is disposed on one side in the first direction of the tooth part; and a second brim part that is disposed on the side opposite from the first brim part in the first direction of the tooth part. The tooth part has a tooth part inner-side surface and a tooth part outer-side surface that are on opposite sides from each other in a second direction, and a tooth part first-side surface and a tooth part second-side surface that are connected to the tooth part inner-side surface and the tooth part outer-side surface and are on opposite sides from each other in a third direction. The tooth part first-side surface and the tooth part second-side surface are disposed parallel to each other and extend straight in the second direction.

Description

Core piece, stator core, stator, and axial gap motor

[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, and an axial gap motor.

[0002] Patent Document 1 describes core pieces that form a stator core of an axial gap motor. The core pieces are powder-pressed compacts and include 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 and the inner circumferential surface. The first side surface and the second side surface of each of the first, second, and third members are formed by a first straight portion, a second straight portion, and a tapered portion so that a plurality of core pieces are adjacent to each other to form an annular stator core. The first straight portion and the second straight portion are surfaces that are parallel to each other on the first side surface and the second side surface, respectively, and the tapered portion is a surface that becomes thinner from the outer peripheral surface side toward the inner peripheral surface side.

[0003] Patent No. 6987327

[0004] In the core piece described in Patent Document 1, a first straight portion, a second straight portion, and a tapered portion are formed on the first side surface and the second side surface, so that the first side surface and the second side surface have complex shapes. Therefore, in order to compact the core piece, a mold with a special shape must be made. Moreover, because the powder is compacted using a mold with a special shape, there is also the problem that the limit to which the density of the core piece can be increased is low.

[0005] Therefore, an object of the present disclosure is to provide a core piece, a stator core, a stator, and an axial gap motor that can be easily manufactured and that can be made highly dense.

[0006] Incidentally, the magnetic flux density of a motor increases as the cross-sectional area of ​​the stator core increases. For this reason, it has been common technical knowledge in the technical field to maximize the cross-sectional area of ​​the stator core by forming the teeth, first flange, and second flange into a shape with a sectorial or trapezoidal cross section in each core piece obtained by dividing the stator core, as described in Patent Document 1.

[0007] However, as a result of extensive research, the present inventors have found that even if the teeth are not formed in a shape having a sectoral or trapezoidal cross section, the motor characteristics of torque and loss may not be reduced to the same level or significantly. The present disclosure has been made in light of this finding.

[0008] [1] The core piece according to the present disclosure is a core piece for a stator core of an axial gap motor, which is formed by pressing soft magnetic powder coated with an insulating material, and includes: a teeth portion having a peripheral surface extending in a first direction and around which a winding is wound; a first flange portion arranged on one side of the teeth portion in the first direction; and a second flange portion arranged on the opposite side of the teeth portion from the first flange portion in the first direction, wherein the teeth portion has teeth portion inner and outer surfaces facing a second direction perpendicular to the first direction, and teeth portion first side and teeth portion second side surfaces connected to the teeth portion inner and outer surfaces and facing a third direction perpendicular to the first and second directions, and the teeth portion first side and teeth portion second side surfaces are arranged parallel to each other and extend linearly in the second direction.

[0009] In this core piece, the first side surface of the tooth portion and the second side surface of the tooth portion are arranged parallel to each other and extend linearly in the second direction. Therefore, the mold for powder-molding the core piece can be simpler in shape than when the teeth are formed with a shape having a sectorial or trapezoidal cross section. This reduces the manufacturing cost of the core piece. Furthermore, since a straight die and upper and lower punches aligned with the pressure direction can be used as the mold for powder-molding the teeth, stress concentration in the teeth can be reduced. This increases the limit for densification of the core piece. This allows for high density of the core piece.

[0010] [2] In the core piece described in [1], the inner surface of the tooth portion and the outer surface of the tooth portion may be arranged parallel to each other and extend linearly in the third direction. In this core piece, the inner surface of the tooth portion and the outer surface of the tooth portion are arranged parallel to each other and extend linearly in the third direction, so that the shape of the mold used to compact the core piece can be further simplified. In other words, upper and lower punches with flat pressing surfaces can be used as the mold used to compact the tooth portion. This further reduces the manufacturing cost of the core piece and enables the density of the core piece to be further increased.

[0011] [3] In the core piece according to [1] or [2], the teeth may be formed in a rectangular parallelepiped shape. In this core piece, the teeth are formed in a rectangular parallelepiped shape, so that the shape of the mold for powder compacting the core piece can be made even simpler. This can further reduce the manufacturing cost of the core piece and further increase the density of the core piece.

[0012] [4] In the core piece according to any one of [1] to [3], the first flange may have a first flange inner end surface and a first flange outer end surface facing in the second direction, and a first flange first end surface and a first flange second end surface connected to the first flange inner end surface and the first flange outer end surface facing in the third direction, the first flange first end surface and the first flange second end surface being parallel to each other and extending linearly in the second direction. In this core piece, the first flange first end surface and the first flange second end surface are parallel to each other and extend linearly in the second direction, which allows the die used to compact the core piece to have a simpler shape than when the first flange is formed with a sectorial or trapezoidal cross section. Moreover, the die used to compact the first flange can use a straight die and upper and lower punches aligned in the pressure direction, thereby reducing stress concentration in the first flange. This allows the manufacturing cost of the core pieces to be further reduced, and also allows the density of the core pieces to be further increased.

[0013] [5] In the core piece described in [4], the first flange inner end surface and the first flange outer end surface may be arranged parallel to each other and extend linearly in the third direction. In this core piece, the first flange inner end surface and the first flange outer end surface are arranged parallel to each other and extend linearly in the third direction, which allows the mold used to compact the core pieces to have a simpler shape. In other words, upper and lower punches with flat pressing surfaces can be used as the mold used to compact the first flange. This further reduces the manufacturing cost of the core pieces and allows for a higher density of the core pieces.

[0014] [6] In the core piece according to any one of [1] to [5], the first flange may be formed in a rectangular plate shape. In this core piece, the first flange is formed in a rectangular plate shape, so that the mold for powder compacting the core piece can have a simpler shape. This can further reduce the manufacturing cost of the core piece and further increase the density of the core piece.

[0015] [7] In the core piece according to any one of [1] to [6], the second flange may have a second flange inner end surface and a second flange outer end surface facing in the second direction, and a second flange first end surface and a second flange second end surface connected to the second flange inner end surface and the second flange outer end surface facing in the third direction, the second flange first end surface and the second flange second end surface being parallel to each other and extending linearly in the second direction. In this core piece, the second flange first end surface and the second flange second end surface are parallel to each other and extend linearly in the second direction, which allows the die used to compact the core piece to have a simpler shape than when the second flange is formed with a sectorial or trapezoidal cross section. Moreover, the die used to compact the second flange can use a straight die and upper and lower punches aligned in the pressure direction, thereby reducing stress concentration in the second flange. This allows the manufacturing cost of the core pieces to be further reduced, and also allows the density of the core pieces to be further increased.

[0016] [8] In the core piece described in [7], the inner end surface of the second flange portion and the outer end surface of the second flange portion may be arranged parallel to each other and extend linearly in the third direction. In this core piece, the inner end surface of the second flange portion and the outer end surface of the second flange portion are arranged parallel to each other and extend linearly in the third direction, so that the shape of the mold used to compact the core piece can be further simplified. In other words, upper and lower punches with flat pressing surfaces can be used as the mold used to compact the second flange portion. This further reduces the manufacturing cost of the core piece and enables the density of the core piece to be further increased.

[0017] [9] In the core piece according to any one of [1] to [8], the second flange may be formed in a rectangular plate shape. In this core piece, the second flange is formed in a rectangular plate shape, so that the mold for powder compacting the core piece can have a simpler shape. This can further reduce the manufacturing cost of the core piece and further increase the density of the core piece.

[0018]

[10] In the core piece according to any one of [1] to [9], the first flange portion and the second flange portion may have the same shape. In this core piece, since the first flange portion and the second flange portion have the same shape, the mold for powder compacting the core piece can have a simpler shape. This can further reduce the manufacturing cost of the core piece.

[0019]

[11] 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

[10] . Because this stator core includes the core pieces described above, the core pieces can be easily manufactured and the density of the core pieces can be increased.

[0020]

[12] A stator according to the present disclosure is a stator for an axial gap motor, and includes the stator core according to

[11] and windings wound around the core pieces of the stator core. Because this stator includes the stator core described above, the core pieces that make up the stator core can be easily manufactured and the core pieces can be made denser.

[0021]

[13] An axial gap motor according to the present disclosure includes the stator described in

[12] and a rotor rotatably disposed relative to the stator. Because this axial gap motor includes the stator described above, the core pieces that make up the stator can be easily manufactured and the core pieces can be made highly dense.

[0022] It can be easily manufactured and can achieve high density.

[0023] 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 cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5. FIG. 9 is a cross-sectional view showing a core piece manufacturing apparatus. FIG. 10 is a cross-sectional view showing a core piece manufacturing apparatus. FIG. 11 is a cross-sectional view showing a core piece manufacturing apparatus. FIG. 12 is a cross-sectional view showing a core piece manufacturing apparatus. FIG. 13 is a plan view showing a die. FIG. 14 is a perspective view showing a core piece of Comparative Example 1. FIG. 15 is a cross-sectional view of the core piece shown in FIG. 14. FIG. 16 is a graph showing the analysis results of Example 1 and Comparative Example 1.

[0024] 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.

[0025] [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.

[0026] [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. In the drawings, as an example, the stator core 5 is shown as having 12 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.

[0027] [Core Lamination] Fig. 3 is a perspective view showing a core lamination according to the embodiment. Fig. 4 is a perspective view showing a core lamination according to the embodiment. Fig. 5 is a front view showing a core lamination according to the embodiment. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 5. Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 5. As shown in Figs. 3 to 8, the core lamination 7 according to this embodiment is a core lamination of the stator core 5 of the axial gap motor 1. In other words, the core lamination 7 constitutes a part of the stator core 5 of the axial gap motor 1.

[0028] 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.

[0029] Each core piece 7 includes a tooth portion 10 extending in a first direction D1, a first flange portion 20 arranged on one side of the tooth portion 10 in the first direction D1, and a second flange portion 30 arranged on the opposite side of the tooth portion 10 in the first direction D1 from the first flange portion 20. Here, the direction perpendicular to the first direction D1 is referred to as a second direction D2, and the direction perpendicular to the first direction D1 and the second direction D2 is referred to as a third direction D3.

[0030] The teeth 10 have peripheral surfaces 11 around which the windings 6 (see FIG. 1 ) are wound. The peripheral surfaces 11 of the teeth 10 have teeth inner surfaces 13 and teeth outer surfaces 14 facing the second direction D2, and teeth first side surfaces 15 and teeth second side surfaces 16 connected to the teeth inner surfaces 13 and teeth outer surfaces 14 and facing the third direction D3. The teeth inner surfaces 13 are surfaces facing the shaft holes 8 in the stator core 5 (the radially inner side of the stator core 5). The teeth outer surfaces 14 are surfaces facing the opposite side of the shaft holes 8 in the stator core 5 (the radially outer side of the stator core 5).

[0031] The tooth inner surface 13 and the tooth outer surface 14 are formed in a planar shape. The tooth inner surface 13 and the tooth outer surface 14 are arranged parallel to each other and extend linearly in the third direction D3. In other words, the tooth inner surface 13 and the tooth outer surface 14 are formed in a planar shape extending along the first direction D1 and the third direction D3.

[0032] The first side surface 15 and the second side surface 16 of the teeth are formed in a planar shape. The first side surface 15 and the second side surface 16 of the teeth are arranged parallel to each other and extend linearly in the second direction D2. In other words, the first side surface 15 and the second side surface 16 of the teeth are formed in a planar shape extending along the first direction D1 and the second direction D2.

[0033] The first side surface 15 of the teeth is connected to one edge of the inner side surface 13 and the outer side surface 14 of the teeth in the third direction D3. The second side surface 16 of the teeth is connected to the edge of the inner side surface 13 and the outer side surface 14 of the teeth opposite to the first side surface 15 of the teeth in the second direction D2.

[0034] The teeth 10 are formed, for example, in a rectangular parallelepiped shape. Furthermore, a cross section of the teeth 10 perpendicular to the first direction D1 (the cross section shown in FIG. 6 ) is formed, for example, in a rectangular shape. The term "the teeth 10 are formed in a rectangular parallelepiped shape" refers not only to the case where the teeth 10 are formed in a perfect rectangular parallelepiped shape, but also to a shape that can be regarded as substantially the same as a rectangular parallelepiped, such as a shape in which the ends of the teeth 10 on the first flange 20 side and the second flange 30 side gradually bulge toward the first flange 20 and the second flange 30. For example, both ends of the teeth inner surface 13, the teeth outer surface 14, the teeth first side surface 15, and the teeth second side surface 16 in the first direction D1 may gradually bulge toward the first flange 20 and the second flange 30.

[0035] The first flange 20 protrudes from the tooth 10 in a direction perpendicular to the first direction D1. The first flange 20 protrudes from the tooth 10 when viewed from the first direction D1. The first flange 20 also protrudes from one end of the tooth 10 in the first direction D1 in directions along the second direction D2 and the third direction D3.

[0036] The first flange portion 20 has a first flange portion outer surface 21 and a first flange portion inner surface 22 that face in the first direction D1. The first flange portion outer surface 21 is a surface that faces the opposite side from the second flange portion 30 in the first direction D1. The first flange portion inner surface 22 is a surface that faces the second flange portion 30 side in the first direction D1 and to which the teeth portion 10 is connected. The first flange portion outer surface 21 and the first flange portion inner surface 22 are arranged parallel to each other and formed into planar shapes that extend in the second direction D2 and the third direction D3.

[0037] The first flange 20 is composed of a first flange inner end face 23 and a first flange outer end face 24 that face the second direction D2, and a first flange first end face 25 and a first flange second end face 26 that are connected to the first flange inner end face 23 and the first flange outer end face 24 and face the third direction D3. The first flange inner end face 23 is a surface that faces the shaft hole 8 side of the stator core 5 (the radially inner side of the stator core 5). The first flange outer end face 24 is a surface that faces the opposite side of the stator core 5 from the shaft hole 8 (the radially outer side of the stator core 5).

[0038] The first flange inner end face 23 and the first flange outer end face 24 are formed in a planar shape. The first flange inner end face 23 and the first flange outer end face 24 are arranged parallel to each other and extend linearly in the third direction D3. In other words, the first flange inner end face 23 and the first flange outer end face 24 are formed in a planar shape extending along the first direction D1 and the third direction D3. Therefore, the first flange inner end face 23 and the first flange outer end face 24 are arranged parallel to the tooth inner side surface 13 and the tooth outer side surface 14 of the tooth portion 10.

[0039] The first flange first end face 25 and the first flange second end face 26 are formed in a planar shape. The first flange first end face 25 and the first flange second end face 26 are arranged parallel to each other and extend linearly in the second direction D2. In other words, the first flange first end face 25 and the first flange second end face 26 are formed in a planar shape extending along the first direction D1 and the second direction D2. Therefore, the first flange first end face 25 and the first flange second end face 26 are arranged parallel to the teeth first side face 15 and the teeth second side face 16 of the teeth portion 10.

[0040] The first flange first end face 25 is connected to one edge in the second direction D2 of the first flange inner end face 23 and the first flange outer end face 24. The first flange second end face 26 is connected to the edge in the second direction D2 of the first flange inner end face 23 and the first flange outer end face 24 on the opposite side from the first flange first end face 25.

[0041] The first flange 20 is formed, for example, in a rectangular plate shape. That is, the first flange 20 is formed, for example, in a rectangular shape when viewed in a plan view, which is the viewing direction from the first direction D1. Furthermore, the cross section of the first flange 20 perpendicular to the first direction D1 (the cross section shown in FIG. 7 ) is formed, for example, in a rectangular shape. The first flange 20 being formed in a rectangular plate shape not only means that the first flange 20 is formed in a completely rectangular plate shape, but also includes a shape that can be considered substantially the same as a rectangular plate shape, such as a shape in which the corners of the first flange outer surface 21, the first flange inner end face 23, the first flange outer end face 24, the first flange first end face 25, and the first flange second end face 26 are rounded.

[0042] The second flange 30 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 from one end of the tooth 10 in the first direction D1 in directions along the second direction D2 and the third direction D3.

[0043] The second flange portion 30 has a second flange portion outer surface 31 and a second flange portion inner surface 32 that face the first direction D1. The second flange portion outer surface 31 is a surface that faces the opposite side from the first flange portion 20 in the first direction D1. The second flange portion inner surface 32 is a surface that faces the first flange portion 20 side in the first direction D1 and to which the teeth portion 10 is connected. The second flange portion outer surface 31 and the second flange portion inner surface 32 are arranged parallel to each other and formed into planar shapes that extend in the second direction D2 and the third direction D3.

[0044] The second flange 30 is composed of a second flange inner end face 33 and a second flange outer end face 34 facing the second direction D2, and a second flange first end face 35 and a second flange second end face 36 connected to the second flange inner end face 33 and the second flange outer end face 34 and facing the third direction D3. The second flange inner end face 33 is a surface facing the shaft hole 8 side of the stator core 5 (the radially inner side of the stator core 5). The second flange outer end face 34 is a surface facing the opposite side of the stator core 5 from the shaft hole 8 (the radially outer side of the stator core 5).

[0045] The second flange inner end face 33 and the second flange outer end face 34 are formed in a planar shape. The second flange inner end face 33 and the second flange outer end face 34 are arranged parallel to each other and extend linearly in the third direction D3. In other words, the second flange inner end face 33 and the second flange outer end face 34 are formed in a planar shape extending along the first direction D1 and the third direction D3. Therefore, the second flange inner end face 33 and the second flange outer end face 34 are arranged parallel to the tooth inner side surface 13 and the tooth outer side surface 14 of the tooth portion 10.

[0046] The second flange first end face 35 and the second flange second end face 36 are formed in a planar shape. The second flange first end face 35 and the second flange second end face 36 are arranged parallel to each other and extend linearly in the second direction D2. In other words, the second flange first end face 35 and the second flange second end face 36 are formed in a planar shape extending along the first direction D1 and the second direction D2. Therefore, the second flange first end face 35 and the second flange second end face 36 are arranged parallel to the teeth first side face 15 and the teeth second side face 16 of the teeth portion 10.

[0047] The second flange first end face 35 is connected to one edge in the second direction D2 of the second flange inner end face 33 and the second flange outer end face 34. The second flange second end face 36 is connected to the edge in the second direction D2 of the second flange inner end face 33 and the second flange outer end face 34 on the opposite side from the second flange first end face 35.

[0048] The second flange 30 is formed, for example, in a rectangular plate shape. That is, the second flange 30 is formed, for example, in a rectangular shape when viewed in a plan view, which is the viewing direction from the first direction D1. Furthermore, the cross section of the second flange 30 perpendicular to the first direction D1 (the cross section shown in FIG. 8 ) is formed, for example, in a rectangular shape. The second flange 30 being formed in a rectangular plate shape not only means that the second flange 30 is formed in a completely rectangular plate shape, but also includes a shape that can be considered substantially the same as a rectangular plate shape, such as a shape in which the corners of the second flange outer surface 31, the second flange inner end face 33, the second flange outer end face 34, the second flange first end face 35, and the second flange second end face 36 are rounded.

[0049] The first flange portion 20 and the second flange portion 30 have the same shape. The first flange portion 20 and the second flange portion 30 are disposed at the same position in the second direction D2 and the third direction D3. That is, the first flange inner end face 23 of the first flange portion 20 and the second flange inner end face 33 of the second flange portion 30 are disposed at the same position in the second direction D2. The first flange outer end face 24 of the first flange portion 20 and the second flange outer end face 34 of the second flange portion 30 are disposed at the same position in the second direction D2. The first flange first end face 25 of the first flange portion 20 and the second flange first end face 35 of the second flange portion 30 are disposed at the same position in the third direction D3. Furthermore, the first flange second end surface 26 of the first flange 20 and the second flange second end surface 36 of the second flange 30 are disposed at the same position in the third direction D3.

[0050] Next, an example of a method for manufacturing the core piece 7 will be described.

[0051] In one example of a method for manufacturing a core piece 7, a powder supplying process, a pressing process, and a removal process are performed in this order using a core piece manufacturing apparatus 100 shown in Figures 9 to 12. Figures 9 to 12 are cross-sectional views showing the core piece manufacturing apparatus. As shown in Figures 9 to 12, the core piece manufacturing apparatus 100 includes a die 110 having a molding hole 111 formed therein, a first lower punch 120, a second lower punch 130, a third lower punch 140, a first spacer 150, and a second spacer 160 which are inserted into the molding hole 111 from below D, and a first upper punch 170, a second upper punch 180, and a third upper punch 190 which are inserted into the molding hole 111 from above U.

[0052] Fig. 13 is a plan view showing the die. Figs. 9 and 11 are cross-sectional views corresponding to line IX-IX in Fig. 13, and Figs. 10 and 12 are cross-sectional views corresponding to line X-X in Fig. 13. As shown in Figs. 9 to 13, the molding hole 111 is a hole with a rectangular cross section that penetrates the die 110 in the up-down direction UD. The molding hole 111 is composed of a tooth space 112 for molding 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 space 115 and a second 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 space 115, and the second space 116 penetrates the die 110 in the up-down direction UD and has the same cross section throughout the entire area in the up-down direction UD.

[0053] 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 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 space 116 is arranged on the opposite side of the tooth space 112 from the first 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.

[0054] The first lower punch 120 is a punch that is inserted into the tooth space 112 of the forming hole 111 from below D. The first lower punch 120 has a straight shape that follows the pressure application direction (movement direction) of the first lower punch 120, and the portion of the first lower punch 120 that is inserted into the tooth space 112 has the same cross section as the tooth space 112. The upper end surface of the first lower punch 120 is a pressure application surface for forming the tooth portion inner surface 13 of the tooth portion 10, and is formed in a flat shape that extends horizontally.

[0055] The second lower punch 130 is a punch that is inserted from below D into the first flange space 113 of the forming hole 111. The second lower punch 130 has a straight shape that follows the pressure application direction (movement direction) of the second lower punch 130, and the portion of the second lower punch 130 that is inserted into the first flange space 113 has the same cross section as the first flange space 113. The upper end surface of the second lower punch 130 is a pressure application surface for forming the first flange inner end surface 23 of the first flange 20, and is formed in a flat shape that extends horizontally.

[0056] The third lower punch 140 is a punch that is inserted from below D into the second flange space 114 of the forming hole 111. The third lower punch 140 has a straight shape that follows the pressure application direction (movement direction) of the third lower punch 140, and the portion of the third lower punch 140 that is inserted into the second flange space 114 has the same cross section as the second flange space 114. The upper end surface of the third lower punch 140 is a pressure application surface for forming the second flange inner end surface 33 of the second flange 30, and is formed in a flat shape that extends horizontally.

[0057] The first spacer 150 is a spacer that is inserted into the first space 115 of the molding hole 111 from below D. The portion of the first spacer 150 that is inserted into the first space 115 has the same cross section as the first space 115. The side surface of the portion of the first spacer 150 that is inserted into the first space 115 is a surface that forms the teeth first side surface 15, a portion of the first flange inner surface 22, and a portion of the second flange inner surface 32, and extends linearly in the up-down direction UD.

[0058] The second spacer 160 is a spacer that is inserted into the second space 116 of the molding hole 111 from below D. The portion of the second spacer 160 that is inserted into the second space 116 has the same cross section as the second space 116. The side surface of the portion of the second spacer 160 that is inserted into the second space 116 is a surface that forms the teeth second side surface 16, a portion of the first flange inner surface 22, and a portion of the second flange inner surface 32, and extends linearly in the up-down direction UD.

[0059] The first lower punch 120, the second lower punch 130, the third lower punch 140, the first spacer 150, and the second spacer 160 may be configured to be able to move independently of each other in the up and down direction UD, or at least a portion of them may be configured as a single unit.

[0060] The first upper punch 170 is a punch that is inserted into the tooth space 112 of the forming hole 111 from above U. The first upper punch 170 has a straight shape that follows the pressure application direction (movement direction) of the first upper punch 170, and the portion of the first upper punch 170 that is inserted into the tooth space 112 has the same cross section as the tooth space 112. The lower end surface of the first upper punch 170 is a pressure application surface for forming the tooth portion outer surface 14 of the tooth portion 10, and is formed in a flat shape that extends horizontally.

[0061] The second upper punch 180 is a punch that is inserted into the first flange space 113 of the forming hole 111 from above U. The second upper punch 180 has a straight shape that follows the pressure application direction (movement direction) of the second upper punch 180, and the portion of the second upper punch 180 that is inserted into the first flange space 113 has the same cross section as the first flange space 113. The lower end surface of the second upper punch 180 is a pressure application surface for forming the first flange outer end surface 24 of the first flange 20, and is formed in a flat shape that extends horizontally.

[0062] The third upper punch 190 is a punch that is inserted into the second flange space 114 of the forming hole 111 from above U. The third upper punch 190 has a straight shape that follows the pressure application direction (movement direction) of the third upper punch 190, and the portion of the third upper punch 190 that is inserted into the second flange space 114 has the same cross section as the second flange space 114. The lower end surface of the third upper punch 190 is a pressure application surface for forming the second flange outer end surface 34 of the second flange 30, and is formed in a flat shape that extends horizontally.

[0063] The first upper punch 170, the second upper punch 180, and the third upper punch 190 may be configured to be able to move independently of one another in the up-down direction UD, or may be configured at least partially as an integrated unit.

[0064] 9 and 10 , in the powder supplying step, the first lower punch 120, the second lower punch 130, the third lower punch 140, the first spacer 150, and the second spacer 160 are inserted from below D into the tooth space 112, the first flange space 113, the second flange space 114, the first space 115, and the second space 116 of the forming hole 111. At this time, the first lower punch 120, the second lower punch 130, the third lower punch 140, the first spacer 150, and the second spacer 160 are moved so that the upper end surfaces of the second upper punch 180 and the third upper punch 190 are positioned above the upper end surfaces of the first upper punch 170 in a direction U, and the upper end surfaces of the first spacer 150 and the second spacer 160 are positioned above the upper end surfaces of the second upper punch 180 and the third upper punch 190 in a direction U. Then, the soft magnetic powder 9 coated with an insulating material is supplied into the molding hole 111 from above U. At this time, the soft magnetic powder 9 is made not to exceed the upper end surfaces of the first spacer 150 and the second spacer 160.

[0065] 12 and 13 , in the pressing process, a first upper punch 170, a second upper punch 180, and a third upper punch 190 are inserted from the upward direction U into the tooth space 112, the first flange space 113, and the second flange space 114 of the forming hole 111. Then, the soft magnetic powder 9 supplied to the forming hole 111 is pressed by at least one of moving the first lower punch 120, the second lower punch 130, and the third lower punch 140 upward toward the upward direction U and moving the first upper punch 170, the second upper punch 180, and the third upper punch 190 downward toward the downward direction D. The soft magnetic powder 9 supplied to the forming hole 111 is pressed between the first lower punch 120 and the first upper punch 170, to form the tooth portion 10 of the core piece 7. Furthermore, the soft magnetic powder 9 is pressed between the second lower punch 130 and the second upper punch 180 to form the first flange 20 of the core piece 7. Furthermore, the soft magnetic powder 9 is pressed between the third lower punch 140 and the third upper punch 190 to form the second flange 30 of the core piece 7. In this way, the core piece 7 is formed as a green compact by pressing the soft magnetic powder 9.

[0066] In the ejection step, the first upper punch 170, the second upper punch 180, and the third upper punch 190 are ejected upward U from the forming hole 111, and the first lower punch 120, the second lower punch 130, and the third lower punch 140 are moved upward U, thereby ejecting the core piece 7 from the forming hole 111. In this way, the core piece 7 is obtained.

[0067] As described above, in this core piece 7, the tooth first side surface 15 and the tooth second side surface 16 are arranged parallel to each other and extend linearly in the second direction D2. This allows the mold used to compact the core piece 7 to be simpler in shape than when the teeth are formed with a shape having a sectorial or trapezoidal cross section. This reduces the manufacturing cost of the core piece 7. Furthermore, since a straight die and upper and lower punches aligned in the pressure direction can be used as the mold used to compact the tooth pieces 10, it is possible to reduce stress concentration in the tooth pieces 10. This increases the limit for densification of the core piece 7. This allows for a high density of the core piece 7.

[0068] Furthermore, in this core piece 7, the tooth inner surface 13 and the tooth outer surface 14 are arranged parallel to each other and extend linearly in the third direction D3, which allows for an even simpler shape of the mold used to compact the core piece 7. In other words, upper and lower punches with flat pressure surfaces can be used as the mold used to compact the tooth piece 10. This allows for a further reduction in the manufacturing cost of the core piece 7 and for the density of the core piece 7 to be further increased.

[0069] Furthermore, in this core piece 7, the teeth 10 are formed in a rectangular parallelepiped shape, which allows for a simpler shape of the mold used for powder compacting the core piece 7. This allows for a further reduction in the manufacturing cost of the core piece 7 and allows for a further increase in the density of the core piece 7.

[0070] Furthermore, in this core piece 7, the first flange first end face 25 and the first flange second end face 26 are arranged parallel to each other and extend linearly in the second direction D2, so the mold used to compact the core piece 7 can be simpler in shape than when the first flange is formed in a shape having a sectorial or trapezoidal cross section. Moreover, since a straight die and upper and lower punches aligned in the pressure direction can be used as the mold for compacting the first flange 20, it is possible to reduce stress concentration in the first flange 20. This further reduces the manufacturing cost of the core piece 7 and enables the density of the core piece 7 to be further increased.

[0071] Furthermore, in this core piece 7, the first flange inner end surface 23 and the first flange outer end surface 24 are arranged parallel to each other and extend linearly in the third direction D3, which allows for an even simpler shape of the mold used to compact the core piece 7. In other words, upper and lower punches with flat pressure surfaces can be used as the mold used to compact the first flange 20. This allows for further reduction in the manufacturing cost of the core piece 7 and further increase in density.

[0072] Furthermore, in this core piece 7, the first flange 20 is formed in a rectangular plate shape, which allows for a simpler shape of the mold for powder compacting the core piece 7. This allows for a further reduction in the manufacturing cost of the core piece 7 and allows for a further increase in the density of the core piece 7.

[0073] Furthermore, in this core piece 7, the second flange first end face 35 and the second flange second end face 36 are arranged parallel to each other and extend linearly in the second direction D2, so the mold used to compact the core piece 7 can be simpler in shape than when the second flange is formed with a shape having a sectorial or trapezoidal cross section. Moreover, since a straight die and upper and lower punches along the pressure direction can be used as the mold for compacting the second flange 30, it is possible to reduce stress concentration in the second flange 30. This further reduces the manufacturing cost of the core piece 7 and enables the density of the core piece 7 to be further increased.

[0074] Furthermore, in this core piece 7, the second flange inner end surface 33 and the second flange outer end surface 34 are arranged parallel to each other and extend linearly in the third direction D3, which allows the mold used to compact the core piece 7 to have an even simpler shape. In other words, upper and lower punches with flat pressure surfaces can be used as the mold used to compact the second flange 30. This allows the manufacturing cost of the core piece 7 to be further reduced, and the density of the core piece 7 to be further increased.

[0075] Furthermore, in this core piece 7, the second flange 30 is formed in a rectangular plate shape, which allows the mold for powder compacting of the core piece 7 to have a simpler shape. This allows the manufacturing cost of the core piece 7 to be further reduced, and the density of the core piece 7 to be further increased.

[0076] Furthermore, in this core piece 7, the first flange portion 20 and the second flange portion 30 have the same shape, so that the mold for powder compacting the core piece 7 can have a simpler shape, which further reduces the manufacturing cost of the core piece 7.

[0077] The stator core 5 according to this embodiment includes the above-described core pieces 7, so that the core pieces 7 can be easily manufactured and the density of the core pieces 7 can be increased.

[0078] The stator 2 according to this embodiment includes the stator core 5 described above, so that the core pieces 7 that make up the stator core 5 can be easily manufactured and the core pieces 7 can be made highly dense.

[0079] The axial gap motor 1 according to this embodiment includes the stator 2 described above, so that the core pieces 7 that make up the stator 2 can be easily manufactured and the core pieces 7 can be arranged at a high density.

[0080] 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.

[0081] For example, in the above embodiment, not only the first side surface and the second side surface of the teeth portion but also the inner side surface and the outer side surface of the teeth portion are described as being parallel to each other and extending linearly in the third direction. However, these surfaces do not necessarily have to be parallel, and may extend in an arc shape to fit the shape of the stator.

[0082] In the above embodiment, the first flange first end face and the first flange second end face of the first flange portion, and the second flange first end face and the second flange second end face of the second flange portion, like the first tooth portion side face and the second tooth portion side face of the teeth portion, are also described as being arranged parallel to each other and extending linearly in the second direction. However, these end faces do not necessarily need to be parallel, and may be formed, for example, in a fan shape or a trapezoid shape so as to minimize the gap between adjacent core pieces.

[0083] Next, examples of the present disclosure will be described, but the present disclosure is not limited to the following examples.

[0084] Example 1 In Example 1, the torque [Nm], loss [W], and ripple rate [%] output from an axial gap motor were analyzed by a simulation using an axial gap motor modeled with the core pieces shown in Figures 3 to 8. The core pieces in Example 1 were formed by pressing magnetic iron powder (ML28D, manufactured by Kobe Steel, Ltd.) at a pressure of 980 MPa, and the teeth portion 10 was a rectangular parallelepiped with a cross section of 16 cm x 8 cm x 2.4 cm (first direction D1 x second direction D2 x third direction D3), the first flange portion 20 was a rectangular plate with a cross section of 24 cm x 30 cm x 13.2 cm (first direction D1 x second direction D2 x third direction D3), and the second flange portion 30 was a rectangular plate with a cross section of 24 cm x 30 cm x 13.2 cm (first direction D1 x second direction D2 x third direction D3). That is, in the core pieces 7 of Example 1, the first tooth side surface 15 and the second tooth side surface 16 of the tooth portion 10 are arranged parallel to each other and extend linearly in the second direction D2. The stator has 12 core pieces 7 arranged in a circular ring shape, and the outer diameter of the stator is φ160 cm and the inner diameter of the stator is φ112 cm. The air gap between the rotors arranged on both sides of the stator is 1 mm. The outer diameter of the rotor is φ168 cm and the inner diameter of the rotor is φ110 cm, and a 2.5 mm thick Nd-Fe-B sintered magnet is used as the magnet. The axial gap motor is air-cooled and has a current of 10 A / mm ２ The analysis results are shown in FIG. 16 and Table 1.

[0085] Comparative Example 1 In Comparative Example 1, the torque [Nm], loss [W], and ripple rate [%] output from an axial gap motor were analyzed by simulation using an axial gap motor including the core pieces 307 shown in FIGS. 14 and 15 as a model. FIG. 14 is a perspective view showing the core piece of Comparative Example 1. FIG. 15 is a cross-sectional view of the core piece shown in FIG. 14 , showing the cross-section corresponding to FIG. 7 . Like the core piece 7 of Example 1, the core piece 307 of Comparative Example 1 includes teeth portions 310 extending in the first direction D1, first flange portions 320 arranged on one side of the teeth portions 310 in the first direction D1, and second flange portions 330 arranged on the opposite side of the teeth portions 310 from the first flange portions 320 in the first direction D1. Core piece 307 of Comparative Example 1 had a trapezoidal cross-section with a length of tooth inner surface 313 in third direction D3 of 5.9 cm, a length of tooth outer surface 314 in third direction D3 of 10.1 cm, and a length from tooth inner surface 313 to tooth outer surface 314 in second direction D2 of 13.2 cm, so that the cross-sectional area and volume were the same as those of core piece 7 of Example 1. The rest of the configuration was the same as that of core piece 7 of Example 1. The axial gap motor of Comparative Example 1 was also under the same conditions as Example 1, except that core piece 307 of Comparative Example 1 was used instead of core piece 7 of Example 1. The analysis results are shown in FIG. 16 and Table 1.

[0086]

[0087] 16 is a graph showing the analysis results of Example 1 and Comparative Example 1. As shown in FIG. 16 and Table 1, the torque average and loss of Example 1 were substantially the same as those of Comparative Example 1. Moreover, the ripple rate of Example 1 was reduced compared to that of Comparative Example 1.

[0088] Example 2 In Example 2, core pieces shown in Figures 3 to 8 were produced. The shape and production conditions of the core pieces in Example 2 were the same as those in the simulation of Example 1. The overall density and density variation of the produced core pieces were measured using the Archimedes method. The overall density was taken as the density of the entire produced core piece. The density variation was determined by splitting the powder-molded core piece in half in the direction of removal from the die, and measuring the difference in density between the part on the punch side and the part on the opposite side of the punch. The measurement results are shown in Table 2.

[0089] (Comparative Example 2) In Comparative Example 2, the core pieces shown in Figures 14 and 15 were produced. The shape and production conditions of the core pieces in Comparative Example 2 were the same as those in the simulation of Comparative Example 1. Then, similar to Example 1, the overall density and density variation of the produced core pieces were measured. The measurement results are shown in Table 2.

[0090]

[0091] As shown in Table 2, the overall density of the core piece of Comparative Example 2 was 7.20 g / cm ３ whereas the overall density of the core pieces of Example 2 was 7.35 g / cm ３ That is, the core pieces of Example 2 were denser than the core pieces of Comparative Example 2. The density variation of the core pieces of Comparative Example 2 was 0.10 g / cm ３ whereas the density variation of the core pieces of Example 2 was 0.20 g / cm ３ That is, the core pieces of Example 2 had a smaller variation in density than the core pieces of Comparative Example 2.

[0092] The present disclosure can be used as a core piece, a stator core, a stator, and an axial gap motor.

[0093] 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, 13...Teeth portion inner surface, 14...Teeth portion outer surface, 15...Teeth portion first side surface, 16...Teeth portion second side surface, 20...First flange portion, 21...first flange portion outer surface, 22...first flange portion inner surface, 23...first flange portion inner end surface, 24...first flange portion outer end surface, 25...first flange portion first end surface, 26...first flange portion second end surface, 30...second flange portion, 31...second flange portion outer surface, 32...second flange portion inner surface, 33...second flange portion inner end surface, 34...second flange portion outer end surface, 35...second flange portion first end surface, 36...second flange portion second 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...first space, 116...second space, 120...first lower punch, 130...second lower punch, 140...third lower punch, 150...first spacer, 160...second spacer, 170...first upper punch, 180...second upper punch, 190...third upper punch, 307...core piece, 310...teeth portion, 313...inner surface of teeth portion, 314...outer surface of teeth portion, 320...first flange portion, 330...second flange portion, D1...first direction, D2...second direction, D3...third direction, D11...first horizontal direction, D12...second horizontal direction, UD...upper / lower direction, U...upper, D...lower.

Claims

1. A core piece for the stator core of an axial gap motor, formed by pressing soft magnetic powder coated with an insulating material, A teeth portion having a circumferential surface extending in a first direction around which the winding is wound, A first flange portion is positioned on one side of the teeth portion in the first direction, The teeth portion comprises a second flange portion located on the opposite side of the first flange portion in the first direction, The teeth portion has an inner surface and an outer surface of the teeth portion facing a second direction perpendicular to the first direction, and a first surface and a second surface of the teeth portion connected to the inner surface and the outer surface of the teeth portion and facing a third direction perpendicular to the first and second directions, The first side surface of the teeth portion and the second side surface of the teeth portion are arranged parallel to each other and extend linearly in the second direction. Core piece.

2. The inner surface and outer surface of the teeth are arranged parallel to each other and extend linearly in the third direction. The core piece according to claim 1.

3. The teeth portion is formed in the shape of a rectangular parallelepiped. The core piece according to claim 1.

4. The first flange portion has an inner end face and an outer end face of the first flange portion facing the second direction, and a first end face and a second end face of the first flange portion connected to the inner end face and the outer end face of the first flange portion and facing the third direction, The first end face of the first flange and the second end face of the first flange are arranged parallel to each other and extend linearly in the second direction. The core piece according to claim 1.

5. The inner end surface and the outer end surface of the first flange are arranged parallel to each other and extend linearly in the third direction. The core piece according to claim 4.

6. The first flange portion is formed in the shape of a rectangular plate. The core piece according to claim 1.

7. The second flange portion has an inner end face and an outer end face of the second flange portion facing the second direction, and a first end face and a second end face of the second flange portion connected to the inner end face and the outer end face of the second flange portion and facing the third direction, The first end face of the second flange and the second end face of the second flange are arranged parallel to each other and extend linearly in the second direction. The core piece according to claim 1.

8. The inner end surface and the outer end surface of the second flange are arranged parallel to each other and extend linearly in the third direction. The core piece according to claim 7.

9. The second flange portion is formed in the shape of a rectangular plate. The core piece according to claim 1.

10. The first flange portion and the second flange portion have the same shape as each other. The core piece according to claim 1.

11. This is the stator core of an axial gap motor, A core piece comprising the one described in any one of claims 1 to 10, Stator core.

12. The stator of an axial gap motor, The stator core according to claim 11, The stator core comprises a winding wound around the core piece of the stator core, stata.

13. The stator described in claim 12, The system comprises a rotor rotatably arranged relative to the stator, Axial gap motor.