Dust compact, core, stator, and rotary electric machine

Abstract

To provide a core piece excellent in productivity.SOLUTION: There is provided a core piece which is arranged annularly to structure a stator core of an axial gap type rotary electric machine. The core piece includes: a columnar first member which extends in an axial direction of the stator core; a plate-like second member which is provided to the first member on the side of a first end part in the axial direction; and a plate-like third member which is provided to the first member on the side of a second end part in the axial direction. The first member has a circumferential face connecting with the second member and the third member, the second member has a projection part projecting outward from the circumferential surface of the first member, and the third member has a projection part projecting outward from the circumferential surface of the first member, the first member, the second member and the third member being formed of an integrated dust compact.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a core piece, a stator core, a stator, and a rotating electric machine. This application claims priority based on Japanese Patent Application No. 2020-082831 filed on May 8, 2020, and incorporates by reference all of the contents of said Japanese application. [Background technology]

[0002] Patent Document 1 discloses a stator core for an axial gap motor, which includes a yoke portion, teeth, and a flange portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-44829 Summary of the Invention

[0004] The core pieces according to the present disclosure are core pieces arranged in a ring shape to construct a stator core of an axial gap type rotating electric machine, and comprise a columnar first member extending in the axial direction of the stator core, a plate-shaped second member provided on a first end side of the first member in the axial direction, and a plate-shaped third member provided on a second end side of the first member in the axial direction, wherein the first member has a peripheral surface connected to the second member and the third member, the second member has a protruding portion that protrudes outward beyond the peripheral surface of the first member, and the third member has a protruding portion that protrudes outward beyond the peripheral surface of the first member, and the first member, the second member, and the third member are constituted by an integrally molded pressed powder compact.

[0005] The stator core according to the present disclosure is a stator core for an axial gap type rotating electric machine, and has a plurality of core pieces arranged in an annular shape, each of which is a core piece according to the present disclosure.

[0006] A stator according to the present disclosure is a stator for an axial gap type rotating electric machine, and includes a stator core according to the present disclosure and a coil disposed on each of the first members of the stator core.

[0007] The rotating electric machine according to the present disclosure is an axial gap type rotating electric machine having a rotor and a stator, the rotor and the stator being arranged facing each other in the axial direction, and the stator is the stator according to the present disclosure. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an outline of a core piece according to the first embodiment. [Figure 2] FIG. 2 is a top view showing an outline of a core piece according to the first embodiment. [Figure 3] FIG. 3 is a view of the core piece according to the first embodiment as viewed from the inner peripheral surface side. [Figure 4] FIG. 4 is a cross-sectional view of the core piece shown in FIG. 3 taken along the line IV-IV. [Figure 5] 5 is a VV cross-sectional view of the core piece shown in FIG. [Figure 6] 6 is a cross-sectional view of the core piece shown in FIG. 3 taken along the line VI-VI. [Figure 7] FIG. 7 is a top view showing the opening edge of a die of a metal mold for manufacturing a core piece according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing an outline of a mold for manufacturing the first member of the core piece according to the first embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing an outline of a mold for manufacturing the second member of the core piece according to the first embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing an outline of a mold for manufacturing a third member in the core piece according to the first embodiment. [Figure 11] FIG. 11 is a perspective view showing an outline of a stator core according to the second embodiment. [Figure 12]FIG. 12 is a perspective view showing an outline of a stator according to the third embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing an outline of a rotating electric machine according to the fourth embodiment. [Figure 14] FIG. 14 is a cross-sectional view showing an outline of a rotating electric machine according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Problem to be solved by this disclosure] It is desirable to improve the productivity of stator cores. It is thought that the productivity of stator cores can be improved by integrally molding the yoke portion, teeth, and flange portion. However, the optimal manufacturing method for integrally molding the yoke portion, teeth, and flange portion has not been fully explored.

[0010] An object of the present disclosure is to provide a core piece that can be manufactured with high productivity. Another object of the present disclosure is to provide a stator core, a stator, and a rotating electric machine that can be manufactured with high productivity.

[0011] [Effects of this disclosure] The core pieces, stator cores, stators, and rotating electrical machines according to the present disclosure are highly productive.

[0012] <<Description of Embodiments of the Present Disclosure>> First, embodiments of the present disclosure will be listed and described.

[0013] (1) A core piece according to one embodiment of the present disclosure is a core piece arranged in a ring to construct a stator core of an axial gap type rotating electric machine, and comprises a columnar first member extending in the axial direction of the stator core, a plate-shaped second member provided on a first end side of the first member in the axial direction, and a plate-shaped third member provided on a second end side of the first member in the axial direction, wherein the first member has a peripheral surface connected to the second member and the third member, the second member has a protruding portion that protrudes outward beyond the peripheral surface of the first member, and the third member has a protruding portion that protrudes outward beyond the peripheral surface of the first member, and the first member, the second member, and the third member are composed of an integrally molded powder compact.

[0014] The core piece according to one aspect of the present disclosure has excellent productivity.

[0015] Conventional core pieces are constructed, for example, by combining a powder compact in which a first member and a second member are integrally molded with a third member configured separately from the powder compact. Alternatively, conventional core pieces are constructed, for example, by combining a powder compact in which a first member and a third member are integrally molded with a second member configured separately from the powder compact. In other words, conventional core pieces must be constructed by manufacturing and combining at least two members. Therefore, the number of steps required to manufacture conventional core pieces is large, and the manufacturing time is long. Furthermore, the manufacturing of conventional core pieces requires at least two molds.

[0016] On the other hand, the core piece according to one embodiment of the present disclosure is composed of a powder compact in which the first member, the second member, and the third member are integrally molded, eliminating the need to combine multiple members. Therefore, the core piece according to one embodiment of the present disclosure can be manufactured with fewer steps and in a shorter time than conventional core pieces. Furthermore, since the core piece according to one embodiment of the present disclosure is composed of a powder compact in which the first member, the second member, and the third member are integrally molded, it can be manufactured using a single mold. Therefore, costs required for mold manufacturing and maintenance can be reduced, and the core piece according to one embodiment of the present disclosure can be manufactured at low cost.

[0017] Conventional core piece powder compacts are manufactured by pressing raw material powder filled into a die cavity of a metal mold with an upper punch and a lower punch. The pressing direction is along the axial direction of the stator core in the core piece, i.e., the direction in which the first and second members are aligned. Of the powder compact, surfaces on the first and second axial end sides of the stator core are formed by the upper end face of the lower punch and the lower end face of the upper punch. Of the powder compact, surfaces on the first and second circumferential sides of the stator core are formed by the inner peripheral surface of the lower punch. Of the powder compact, surfaces on the outer and inner peripheral sides of the stator core are formed by the inner peripheral surface of the die cavity. That is, the first axial end face of the first member and the first axial end face of the second member are formed by the upper end face of the lower punch. The second axial end face of the second member is formed by the lower end face of the upper punch. The first axial end face and the second circumferential end face of the first member are formed by the inner peripheral surface of the lower punch. The outer and inner surfaces of the first and second members are formed by the inner peripheral surface of the die cavity. The direction in which the powder compact is released from the die is the same as the direction of pressure application, and is the direction along the axial direction of the stator core in the core pieces, i.e., the direction in which the first and second members are aligned.

[0018] The core piece according to one aspect of the present disclosure cannot be manufactured by a conventional manufacturing method that follows the same pressing and removal directions as the core piece because the second and third members each have protrusions that get caught on the inner circumferential surface of the die cavity, preventing the core piece from being removed from the mold.

[0019] A core piece according to one aspect of the present disclosure can be manufactured by setting the pressure direction and the removal direction along the radial direction of the stator core, as will be described in detail later. The outer and inner peripheral surfaces of the core piece are formed by the lower end surface of the upper punch and the upper end surface of the lower punch. The first and second circumferential surfaces of the core piece, and the first and second axial end surfaces of the stator core, are formed by the inner peripheral surface of the die cavity. In this case, even if the second and third members each have protrusions, the protrusions do not get caught on the inner peripheral surface of the die cavity. Therefore, the core piece can be removed from the mold.

[0020] (2) In one embodiment of the core pieces, each of the first member, the second member, and the third member has an outer peripheral surface disposed on the outer peripheral side of the stator core, an inner peripheral surface disposed on the inner peripheral side of the stator core, a first side surface disposed on a first direction side in the circumferential direction of the stator core and connected to the outer peripheral surface and the inner peripheral surface, and a second side surface disposed on a second direction side in the circumferential direction of the stator core and connected to the outer peripheral surface and the inner peripheral surface, and in each of the first member, the second member, and the third member, the length between the first side surface and the second side surface on the outer peripheral surface is and each of the first side surface and the second side surface in each of the first member, the second member, and the third member has a first parallel surface connected to the outer circumferential surface, a second parallel surface connected to the inner circumferential surface, and a first inclined surface connected to the first parallel surface and the second parallel surface, and in each of the first member, the second member, and the third member, the first parallel surface of the first side surface and the first parallel surface of the second side surface are parallel, the second parallel surface of the first side surface and the second parallel surface of the second side surface are parallel, and the first parallel surface of the first side surface and the second parallel surface of the first side surface are parallel.

[0021] The core pieces have a high relative density for the following reasons: the first parallel surface and the second parallel surface can be formed by straight portions along the pressure direction of the upper and lower punches in the die cavity of the metal mold, as will be described in detail later. Therefore, sufficient pressure can be applied to the raw material powder that constitutes the core pieces.

[0022] The core pieces described above have excellent productivity. The reason for this is as follows. As will be described in detail later, the first inclined surface can be formed by a tapered portion in the die cavity of the metal mold that intersects with the pressure direction of the upper punch and the lower punch. By having a straight portion in the die cavity, contact between the upper punch and the lower punch and the inner surface of the tapered portion is suppressed. This extends the life of the mold, and increases the number of core pieces that can be produced with one mold.

[0023] (3) As one embodiment of the core piece of (2) above, in each of the first member, the second member, and the third member, the angle between the extension of the first parallel surface of the first side surface and the first inclined surface is 5° or more and 20° or less, and the angle between the extension of the first parallel surface of the second side surface and the first inclined surface is 5° or more and 20° or less.

[0024] When the angle between the core pieces and the first member satisfies the above range, it is easy to wind the windings around the circumferential surface of the first member and to construct a stator. When the angle between the core pieces and the second member satisfies the above range, it is easy to arrange the core pieces in an annular shape and to construct a stator core. When the angle between the core pieces and the third member satisfies the above range, it is possible to suppress density variations within the core pieces.

[0025] (4) As one embodiment of the core piece of (2) or (3), each of the protruding portion of the second member and the protruding portion of the third member has a first protruding portion that protrudes toward a first direction in the circumferential direction and a second protruding portion that protrudes toward a second direction in the circumferential direction, a protruding amount of the first protruding portion of the second member is larger than a protruding amount of the first protruding portion of the third member, a protruding amount of the second protruding portion of the second member is larger than a protruding amount of the second protruding portion of the third member, and the first inclined surface of the first protruding portion of the second member is located outside a first imaginary plane. the first inclined surface of the second protruding portion of the second member has a portion that protrudes outward beyond the second imaginary plane, the first imaginary plane is a plane that connects, on the first side surface of the first protruding portion of the second member, a connection point between the first parallel surface and the first inclined surface and a connection point between the second parallel surface and the inner circumferential surface, and the second imaginary plane is a plane that connects, on the second side surface of the second protruding portion of the second member, a connection point between the first parallel surface and the first inclined surface and a connection point between the second parallel surface and the inner circumferential surface.

[0026] The above core pieces make it easy to construct a stator core with a large magnetic path area for the following reasons.

[0027] The stator core is formed by arranging a plurality of core pieces in an annular shape. Some stator cores are formed by assembling first core pieces and second core pieces that are adjacent in the circumferential direction so as to be in contact with each other.

[0028] For example, in the case of a core piece in which the first side surface of the first protruding portion and the second side surface of the second protruding portion each have a first parallel surface, a second parallel surface, and a first inclined surface, and the first inclined surface does not have the protruding portion, the following occurs. When the core pieces are arranged in an annular shape, if an attempt is made to bring the first side surface of the first protruding portion of the second member of the first core piece into contact with the second side surface of the second protruding portion of the second member of the second core piece, a first corner of the first core piece comes into contact with a second corner of the second core piece. The first corner is a corner between the first side surface of the first protruding portion of the second member and the inner circumferential surface. The second corner is a corner between the second side surface of the second protruding portion of the second member and the inner circumferential surface. Therefore, the first side surface of the first protruding portion of the second member of the first core piece and the second side surface of the second protruding portion of the second member of the second core piece cannot be brought into sufficient contact.

[0029] In contrast, in the core pieces, the first side surface of the first protruding portion and the second side surface of the second protruding portion each have a first parallel surface, a second parallel surface, and a first inclined surface, and the first inclined surface has a portion that protrudes beyond the first imaginary plane and the second imaginary line. When the core pieces are arranged in an annular shape, even if the first side surface of the first protruding portion of the second member of the first core piece is brought into contact with the second side surface of the second protruding portion of the second member of the second core piece, contact between the first corner of the first core piece and the second corner of the second core piece can be prevented. Therefore, the first side surface of the first protruding portion of the second member of the first core piece and the second side surface of the second protruding portion of the second member of the second core piece can be brought into sufficient contact.

[0030] (5) As one embodiment of the core piece of (4) above, the first side surface of the first protrusion in the second member has one selected from the group consisting of at least one of a recess and a protrusion, a step, and a second inclined surface, and the second side surface of the second protrusion in the second member has one selected from the group consisting of at least one of a protrusion corresponding to the recess of the first side surface and a recess corresponding to the protrusion of the first side surface, a step corresponding to the step of the first side surface, and a second inclined surface corresponding to the second inclined surface of the first side surface.

[0031] The above core pieces make it easy to construct a stator core with a large magnetic path area. The reason is as follows: First core pieces and second core pieces adjacent to each other in the circumferential direction of the stator core can be fitted together at the steps or the concaves and convexes, or can be brought into contact with each other at the second inclined surfaces. Therefore, the first core pieces and the second core pieces can be brought into sufficient contact with each other, thereby increasing the contact area between the first core pieces and the second core pieces.

[0032] (6) In one embodiment of the core piece of (4) or (5) above, the third member has a first end face that is arranged on the opposite side to the side facing the second member, and the first end face is convex toward the opposite side.

[0033] The above core pieces can be used to construct a rotating electric machine with low noise and vibration. The reasons are as follows: In a rotating electric machine, a stator and a rotor are arranged facing each other. The stator is configured by arranging a coil in each first member of a stator core. The stator core is configured by arranging a plurality of core pieces in an annular shape. Because the first end faces of the core pieces are convex, sudden changes in the magnetic flux of the rotor magnet that is received by the core pieces are easily suppressed. Because sudden changes in magnetic flux are easily suppressed, cogging torque is easily reduced. Because the cogging torque is small, noise and vibration are less likely to increase.

[0034] (7) As one form of the core piece of any one of (2) to (6) above, the outer peripheral surface of each of the first member, the second member, and the third member has a curved surface that is convex toward the outer peripheral side, and the inner peripheral surface of each of the first member, the second member, and the third member has a curved surface that is convex toward the inner peripheral side.

[0035] The core piece can suppress variations in density within the core piece.

[0036] (8) As one form of the core piece of any one of (2) to (7) above, a first joint between the protruding portion of the second member and the peripheral surface of the first member, and a second joint between the protruding portion of the third member and the peripheral surface of the first member are rounded.

[0037] The core pieces are less likely to be damaged starting from the respective joints because the first joint and the second joint are rounded.

[0038] (9) In one embodiment of the core piece of (8) above, the bending radius of the first joint and the bending radius of the second joint are 0.2 mm or more and 4.0 mm or less.

[0039] The core pieces have a bending radius of 0.2 mm or more at the first joint and the second joint, which reduces the load on the mold during manufacturing the core pieces.The core pieces have a bending radius of 4.0 mm or less at the first joint and the second joint, which makes it easy to wind the coil when constructing the stator, making it easy to increase the number of coil turns.

[0040] (10) As one form of the core piece of any one of (2) to (9) above, the second member and the third member each have a first end face arranged on the opposite side from the sides facing each other, and in each of the second member and the third member, the corners between the outer peripheral surface and the first end face and the corners between the inner peripheral surface and the first end face are chamfered.

[0041] The corners of the core pieces are chamfered, so that the corners are less likely to be damaged.

[0042] (11) As one embodiment of the core piece of any one of (2) to (10) above, the total area of ​​the outer peripheral surface of each of the first member, the second member, and the third member is more than 1 time and not more than 4 times the total area of ​​the inner peripheral surface of each of the first member, the second member, and the third member.

[0043] The core pieces are easy to arrange in an annular shape and to construct a stator core because the total area of ​​the outer peripheral surfaces is more than one time the total area of ​​the inner peripheral surfaces. The core pieces are easy to manufacture because the total area of ​​the outer peripheral surfaces is four times or less the total area of ​​the inner peripheral surfaces. The relatively high ratio of the total area of ​​the inner peripheral surfaces provides a large area for the lower punch to push out the core pieces when removing them from the mold. This makes it easy to prevent damage to the core pieces when removing them from the mold.

[0044] (12) As one embodiment of the core piece of any one of (2) to (11) above, among the regions obtained by dividing the core piece into three parts by an imaginary plane along the second parallel plane of the first side surface and an imaginary plane along the second parallel plane of the second side surface, the difference in relative density between a first region on the first direction side of the circumferential direction and a second region on the second direction side of the circumferential direction and a third region between the first region and the second region is 5.0% or less.

[0045] The core pieces have small differences in relative density, so that the physical properties, such as magnetic properties, are substantially uniform within the core pieces.

[0046] (13) One embodiment of the core piece is that the difference in relative density between the first member, the second member, and the third member having the highest relative density and the member having the lowest relative density is 5% or less.

[0047] The core pieces have small differences in relative density, so that the physical properties, such as magnetic properties, are substantially uniform within the core pieces.

[0048] (14) In one embodiment of the core piece, the powder compact has a relative density of 85% or more.

[0049] The core pieces have a relative density of 85% or more, which is high density, and therefore an axial gap type rotating electric machine having excellent magnetic properties such as saturation magnetic flux density can be constructed. Furthermore, the core pieces have excellent mechanical properties such as strength.

[0050] (15) In one embodiment of the core piece, the powder compact is composed of an aggregate of a plurality of coated soft magnetic particles having an insulating coating on the surface of the soft magnetic particles, and the soft magnetic particles are iron-based particles made of at least one metal selected from the group consisting of pure iron, Fe-Si-based alloys, Fe-Al-based alloys, and Fe-Si-Al-based alloys.

[0051] The core pieces have high density and excellent dimensional accuracy because the material is relatively soft and the soft magnetic particles are easily deformed during compaction into a powder compact.

[0052] (16) A stator core according to one embodiment of the present disclosure is a stator core for an axial gap type rotating electric machine, and has a plurality of core pieces arranged in a ring shape, each of which is any one of the core pieces described above in (1) to (15).

[0053] The stator core has excellent productivity because each of the plurality of core pieces arranged in an annular shape is the core piece having excellent productivity.

[0054] (17) In one embodiment of the stator core, the variation in length between the surface on the first end side and the surface on the second end side in the axial direction of each of the plurality of core pieces is 0.1 mm or less.

[0055] The stator core has very little variation in length. Therefore, the stator core can be used to build a rotating electric machine with little noise and vibration. The reason for this is as follows: As described above, a rotating electric machine has a stator configured by arranging a coil on the first member of each core piece of the stator core, and a rotor arranged opposite each other. Since the variation in length of the stator core is small, the variation in the gap between the stator and the rotor is also small. The small variation in the gap reduces torque ripple. The small torque ripple makes it less likely for noise and vibration to increase.

[0056] (18) A stator according to one aspect of the present disclosure is a stator for an axial gap type rotating electric machine, and includes a stator core according to (16) or (17) above, and a coil arranged on each of the first members in the stator core.

[0057] The stator has a stator core that is easy to produce, and therefore is easy to produce.

[0058] (19) A rotating electric machine according to one embodiment of the present disclosure is an axial gap type rotating electric machine comprising a rotor and a stator, the rotor and the stator being arranged facing each other in the axial direction, and the stator being the stator described above in (18).

[0059] The rotating electrical machine described above has excellent productivity because it includes a stator that is excellent in productivity.

[0060] Details of the embodiments of the present disclosure DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the embodiments of the present disclosure will be described below with reference to the drawings, in which the same reference numerals indicate the same objects.

[0061] First Embodiment 〔core〕 A core lamination 1 according to a first embodiment will be described with reference to FIGS. 1 to 6. The core laminations 1 of this embodiment are arranged in an annular shape to form a stator core 7, as will be described later with reference to FIG. 11. The stator core 7 is used in an axial gap rotating electric machine 9, as will be described later with reference to FIGS. 13 and 14. As shown in FIG. 1, the core laminations 1 of this embodiment include a columnar first member 10, a plate-shaped second member 20, and a plate-shaped third member 30. The first member 10 extends in the axial direction of the stator core 7. The second member 20 is provided on a first end side of the first member 10 in the axial direction. The third member 30 is provided on a second end side of the first member 10 in the axial direction. One of the features of the core laminations 1 of this embodiment is that the second member 20 and the third member 30 each have specific protrusions 21, 31, and the first member 10, the second member 20, and the third member 30 are integrally molded to form a powder compact. Being integrally molded means that the first member 10, the second member 20, and the third member 30 are formed as a single unit by molding, without being mechanically connected using screws or the like, or bonded with adhesives or the like. This will be explained in detail below.

[0062] The direction along the radial direction of the stator core 7 in the core lamination 1 is defined as the X-axis direction. The direction along the axial direction of the stator core 7 in the core lamination 1 is defined as the Z-axis direction. The direction perpendicular to both the X-axis direction and the Z-axis direction of the core lamination 1 is defined as the Y-axis direction. In the X-axis direction, the inner circumferential side of the stator core 7 in the core lamination 1 is defined as an X1 direction, and the outer circumferential side of the stator core 7 is defined as an X2 direction. In the Z-axis direction, the second member 20 side relative to the first member 10 in the core piece 1 is the Z1 direction, and the third member 30 side relative to the first member 10 is the Z2 direction. The Z1 direction is the first end side of the first member 10. The Z2 direction is the second end side of the first member 10. In the Y-axis direction, a first direction side of the stator core 7 in the core lamination 1 is defined as a Y1 direction, and a second direction side of the stator core 7 is defined as a Y2 direction.

[0063] [First member] The first member 10 is a columnar member extending in the Z-axis direction. The first member 10 forms teeth whether the core pieces 1 are used to construct a stator core 7 of a double stator / single rotor configuration for an axial gap type rotating electric machine 9 or a stator core 7 of a single stator / double rotor configuration for an axial gap type rotating electric machine 9. An axial gap type rotating electric machine 9 of a double stator / single rotor configuration is assembled so that one rotor 90 is sandwiched between two stators 8, as shown in FIG. 13. An axial gap type rotating electric machine 9 of a single stator / double rotor configuration is assembled so that one stator 8 is sandwiched between two rotors 90, as shown in FIG. 14. Hereinafter, for convenience of explanation, a double stator / single rotor may be referred to as DS / SR, and a single stator / double rotor may be referred to as SS / DR.

[0064] The shape of the first member 10 may be, for example, a rectangular prism or a cylindrical shape. Examples of rectangular prisms include a quadrangular prism, which has a rectangular cross section cut along a plane perpendicular to the Z-axis direction. Examples of quadrangular prisms include a trapezoidal prism, which has a trapezoidal cross section. The cross section may be uniform in the Z-axis direction. The term "trapezoid" refers not only to a geometric trapezoid but also to shapes with rounded corners, such as in this example, that are essentially considered trapezoids. The term "trapezoid" includes trapezoids with both legs of the same length, such as an isosceles trapezoid, as well as trapezoids with both legs of different lengths, such as a right-angled trapezoid. This also applies to the second member 20 and the third member 30, which will be described later.

[0065] As shown in FIGS. 1 and 4, the shape of the first member 10 in this embodiment is a trapezoidal column, with the cross-sectional shape being trapezoidal. The cross-sectional shape has a longer side on the X2 direction side and a shorter side on the X1 direction side. The cross-sectional shape of the first member 10 is uniform in the Z-axis direction. If the shape of the first member 10 is a trapezoidal column, it is easy to ensure a large cross-sectional area. Furthermore, it is easy to reduce the dead space of the core laminations 1, and it is easy to construct a stator 8 with a high space factor.

[0066] As shown in FIGS. 1 and 3 , the first member 10 has a circumferential surface 11 that is connected to the second member 20 and the third member 30. The circumferential surface 11 of the first member 10 shown in FIGS. 1 and 3 has an outer circumferential surface 12, an inner circumferential surface 13, a first side surface 14a, and a second side surface 14b as shown in FIG. 4 . The outer circumferential surface 12 is located on the X2 direction side. The inner circumferential surface 13 is located on the X1 direction side. The first side surface 14a and the second side surface 14b are located on opposite sides of the core lamination 1 in the circumferential direction of the stator core 7. That is, the first side surface 14a is located on the first direction side of the circumferential direction of the stator core 7. The second side surface 14b is located on the second direction side of the circumferential direction of the stator core 7. The positional relationships between the outer circumferential surface 12, the inner circumferential surface 13, the first side surface 14a, and the second side surface 14b are the same for the second member 20 and the third member 30, which will be described later.

[0067] The outer peripheral surface 12 is connected to the outer peripheral edge of the first side surface 14a and the outer peripheral edge of the second side surface 14b. The inner peripheral surface 13 is connected to the inner peripheral edge of the first side surface 14a and the inner peripheral edge of the second side surface 14b. That is, the first side surface 14a and the second side surface 14b are connected to the outer peripheral surface 12 and the inner peripheral surface 13.

[0068] The length between the first side surface 14a and the second side surface 14b on the outer peripheral surface 12 is longer than the length between the first side surface 14a and the second side surface 14b on the inner peripheral surface 13. In this embodiment, the outer peripheral surface 12 has a curved surface that is convex toward the X2 direction. The outer peripheral surface 12 may be configured as a flat surface. In this embodiment, the inner peripheral surface 13 has a curved surface that is convex toward the X1 direction. The inner peripheral surface 13 may have a curved surface that is convex toward the X2 direction, or may be configured as a flat surface. The bending radii of the outer peripheral surface 12 and the inner peripheral surface 13 may be the same or different from each other.

[0069] Each of the first side surface 14a and the second side surface 14b has a first parallel surface 141, a second parallel surface 142, and a first inclined surface 143. The first parallel surfaces 141 of the first side surface 14a and the second side surface 14b are parallel to each other. The second parallel surfaces 142 of the first side surface 14a and the second side surface 14b are parallel to each other. The first parallel surface 141 of the first side surface 14a and the second parallel surface 142 of the first side surface 14a are parallel to each other. The first parallel surface 141 and the second parallel surface 142 are parallel to the X-axis direction of the core lamination 1. The X-axis direction refers to the direction along a straight line that passes through the center of the stator core 7 and bisects the core lamination 1 in the circumferential direction of the stator core 7. The first parallel surface 141 is contiguous with the outer peripheral surface 12. The second parallel surface 142 is contiguous with the inner peripheral surface 13. The first inclined surface 143 is contiguous with the first parallel surface 141 and the second parallel surface 142.

[0070] The length of the first parallel surface 141 and the second parallel surface 142 along the X-axis direction depends on the size of the core piece 1, and is preferably, for example, 0.3 mm or more and 25 mm or less. If it is equal to or greater than the above-mentioned lower limit, damage to the mold 5 due to contact between the lower punch 55 and the die 50, which will be described later with reference to FIG. 7, can be suppressed. Although a manufacturing method of the core piece 1 will be described later, if it is equal to or greater than the above-mentioned lower limit, sufficient pressure can be applied to the raw material powder constituting the core piece 1. If it is equal to or less than the above-mentioned upper limit, the cross-sectional area of ​​the first member 10 can be increased, thereby improving torque and suppressing iron loss in the axial gap type rotating electric machine 9. The length of the first parallel surface 141 and the second parallel surface 142 along the X-axis direction is further preferably equal to or greater than 0.4 mm and 20 mm or less, and particularly preferably equal to or greater than 0.5 mm and 15 mm or less. The above-mentioned preferred ranges of the lengths along the X-axis direction of the first parallel surfaces 141 and the second parallel surfaces 142 on each of the first side surface 14a and the second side surface 14b of the first member 10 are also the same for the first parallel surfaces 241 and the second parallel surfaces 242 on each of the first side surface 24a and the second side surface 24b of the second member 20, which will be described later, and the first parallel surfaces 341 and the second parallel surfaces 342 on each of the first side surface 34a and the second side surface 34b of the third member 30.

[0071] As shown in FIG. 4 , the first inclination angle θ11 and the second inclination angle θ12 of the first inclined surface 143 are preferably, for example, 5° to 20°. When the first inclination angle θ11 and the second inclination angle θ12 are 5° to 20°, it is easy to wind a winding (described later) around the circumferential surface 11 of the first member 10, making it easy to construct the stator core 7 shown in FIG. 11 . The first inclination angle θ11 and the second inclination angle θ12 are preferably 5.5° to 18°, and particularly preferably 6° to 16°. The first inclination angle θ11 and the second inclination angle θ12 are preferably the same angle, but may be different. The first inclination angle θ1 refers to the angle between the first inclined surface 143 and an extension E11 of the first parallel surface 141 on the first side surface 14a. The second inclination angle θ12 refers to the angle between the first inclined surface 143 and an extension E12 of the first parallel surface 141 on the second side surface 14b.

[0072] [Second member] 1 and 3, the second member 20 is a plate-shaped member provided on the first end side in the Z-axis direction of the first member 10. When the core pieces 1 are used to construct a stator core 7 provided in an axial gap type rotating electric machine 9 of DS / SR configuration, the second member 20 forms a yoke. When the core pieces 1 are used to construct a stator core 7 provided in an axial gap type rotating electric machine 9 of SS / DR configuration, the second member 20 forms a flange.

[0073] In this embodiment, the second member 20 has a trapezoidal plate shape. The trapezoidal plate shape is a trapezoidal cross section obtained by cutting the second member 20 along a plane perpendicular to the Z-axis direction. The cross section is uniform in the Z-axis direction. Note that the shape of the second member 20 may be a rectangular plate when the core pieces 1 are used to construct a stator core 7 provided in an axial gap type rotating electric machine 9 of SS / DR configuration.

[0074] As shown in FIGS. 1 to 3 , the second member 20 has a protruding portion 21. The protruding portion 21 protrudes outward from the circumferential surface 11 of the first member 10. The protruding portion 21 may protrude outward from the circumferential surface 11 of the first member 10 in a portion of the circumferential surface 11 of the first member 10, or may protrude outward from the circumferential surface 11 of the first member 10 over the entire circumferential circumference of the first member 10. In this embodiment, the protruding portion 21 has a first protruding portion 211 and a second protruding portion 212. The first protruding portion 211 protrudes toward the second direction in the circumferential direction of the stator core 7. The second protruding portion 212 protrudes toward the second direction in the circumferential direction of the stator core 7. Note that the protruding portion 21 may not have the first protruding portion 211 and the second protruding portion 212, and may have a portion protruding toward the X1 direction and a portion protruding toward the X2 direction. The protruding portion 21 may have a portion that protrudes in the X1 direction and a portion that protrudes in the X2 direction, in addition to the first protruding portion 211 and the second protruding portion 212. In this case, the protruding portion 21 is provided in an annular shape.

[0075] When the core pieces 1 are used to construct a stator core 7 included in an axial gap type rotating electric machine 9 of a DS / SR configuration, the protruding lengths of the first protruding portions 211 and the second protruding portions 212 of the second member 20 are longer than the protruding lengths of the first protruding portions 211 and the second protruding portions 212 of the third member 30, which will be described later. When the core pieces 1 are used to construct a stator core 7 included in an axial gap type rotating electric machine 9 of a SS / DR configuration, the protruding lengths of the first protruding portions 211 and the second protruding portions 212 of the second member 20 may be set to the same as the protruding lengths of the first protruding portions 211 and the second protruding portions 212 of the third member 30. The protruding length refers to the length along a direction perpendicular to the circumferential surface 11 of the first member 10. When the circumferential surface 11 has a curved surface, the protruding length refers to the length along a normal direction to the curved surface.

[0076] As shown in FIGS. 3 and 5 , the second member 20 has an outer peripheral surface 22, an inner peripheral surface 23, a first side surface 24a, a second side surface 24b, a first end surface 26, and a second end surface 27. As described above, the positional relationship between the outer peripheral surface 22, the inner peripheral surface 23, the first side surface 24a, and the second side surface 24b is the same as the positional relationship between the respective surfaces in the first member 10. The first end surface 26 and the second end surface 27 are disposed facing each other. The first end surface 26 is located on the Z1 direction side. The first end surface 26 is located on the Z1 direction side of the second member 20. The second end surface 27 is located on the Z2 direction side. The second end surface 27 is located on the first member 10 side of the second member 20. The positional relationship between the first end surface 26 and the second end surface 27 is the same in the third member 30 described below.

[0077] The outer peripheral surface 22 is continuous with the outer peripheral edge of the first side surface 24a, the outer peripheral edge of the second side surface 24b, the outer peripheral edge of the first end surface 26, and the outer peripheral edge of the second end surface 27. The outer peripheral surface 22 of the second member 20 is continuous with the outer peripheral surface 12 of the first member 10. The inner peripheral surface 23 is continuous with the inner peripheral edge of the first side surface 24a, the inner peripheral edge of the second side surface 24b, the inner peripheral edge of the first end surface 26, and the inner peripheral edge of the second end surface 27. The inner peripheral surface 23 of the second member 20 is continuous with the inner peripheral surface 13 of the first member 10. The first side surface 24a and the second side surface 24b are continuous with the outer peripheral surface 22 and the inner peripheral surface 23. The first end surface 26 is continuous with the outer peripheral surface 22, the first side surface 24a, the second side surface 24b, and the inner peripheral surface 23. The second end surface 27 is connected to the outer peripheral surface 22 , the first side surface 24 a , the second side surface 24 b , the inner peripheral surface 23 , and the peripheral surface 11 of the first member 10 .

[0078] The length between the first side surface 24a and the second side surface 24b at the outer peripheral surface 22 is longer than the length between the first side surface 24a and the second side surface 24b at the inner peripheral surface 23. The length between the first side surface 24a and the second side surface 24b at the outer peripheral surface 22 of the second member 20 is longer than the length between the first side surface 14a and the second side surface 14b at the outer peripheral surface 11 of the first member 10. The length between the first side surface 24a and the second side surface 24b at the inner peripheral surface 23 of the second member 20 is the same as the length between the first side surface 14a and the second side surface 14b at the inner peripheral surface 13 of the first member 10.

[0079] In this embodiment, the outer peripheral surface 22 has a curved surface that is convex toward the X2 direction. The outer peripheral surface 22 may be configured as a flat surface. In this embodiment, the inner peripheral surface 23 has a curved surface that is convex toward the X1 direction. The inner peripheral surface 23 may have a curved surface that is convex toward the X2 direction, or may be configured as a flat surface. The bending radii of the outer peripheral surface 22 and the inner peripheral surface 23 may be the same or different from each other.

[0080] Each of the first side surface 24a and the second side surface 24b has a first parallel surface 241, a second parallel surface 242, and a first inclined surface 243. The first parallel surfaces 241 of the first side surface 24a and the second side surface 24b are parallel to each other. The second parallel surfaces 242 of the first side surface 24a and the second side surface 24b are parallel to each other. The first parallel surface 241 of the first side surface 24a and the second parallel surface 242 of the first side surface 24a are parallel to each other. The first parallel surface 241 and the second parallel surface 242 are surfaces parallel to the X-axis direction of the core piece 1. The first parallel surface 241 is contiguous with the outer peripheral surface 22. The second parallel surface 242 is contiguous with the inner peripheral surface 23. The first inclined surface 243 is contiguous with the first parallel surface 241 and the second parallel surface 242.

[0081] As shown in FIG. 5 , the first inclination angle θ21 and the second inclination angle θ22 of the first inclined surface 243 are preferably, for example, 5° or more and 20° or less. When the first inclination angle θ21 and the second inclination angle θ22 are 5° or more and 20° or less, it is easy to arrange the core pieces 1 in an annular shape, and it is easy to construct the stator core 7. The first inclination angle θ21 and the second inclination angle θ22 are preferably 5.5° or more and 18° or less, and particularly preferably 6° or more and 16° or less. The first inclination angle θ21 and the second inclination angle θ22 are preferably the same angle, but may be different. The first inclination angle θ21 refers to the angle between the first inclined surface 243 and an extension E21 of the first parallel surface 241 on the first side surface 24a. The second inclination angle θ22 refers to the angle between the first inclined surface 243 and an extension E22 of the first parallel surface 241 on the second side surface 24b.

[0082] When constructing a stator core 7 in an axial gap type rotating electric machine 9 in which the core laminations 1 are of DS / SR configuration, a first core lamination 1 and a second core lamination 1 adjacent to each other in the circumferential direction of the stator core 7 are in contact with each other at the first side surface 24a of the second member 20 of the first core lamination 1 and the second side surface 24b of the second member 20 of the second core lamination 1. In this case, the first inclined surface 243 of the first side surface 24a preferably has a portion 244 that protrudes outward from the first imaginary plane V21. The first inclined surface 243 of the second side surface 24b preferably has a portion 244 that protrudes outward from the second imaginary plane V22.

[0083] The first imaginary plane V21 is a plane that connects the first connection point and the second connection point on the first side surface 24a of the first protruding portion 211. The first connection point on the first side surface 24a is a connection point between the first parallel surface 241 and the first inclined surface 243 of the first side surface 24a. The second connection point on the first side surface 24a is a connection point between the second parallel surface 242 of the first side surface 24a and the inner circumferential surface 23. The second imaginary plane V22 is a plane that connects the first connection point and the second connection point on the second side surface 24b of the second protruding portion 212. The first connection point on the second side surface 24b is a connection point between the first parallel surface 241 and the first inclined surface 243 of the second side surface 24b. The second connection point on the second side surface 24b is a connection point between the second parallel surface 242 of the second side surface 24b and the inner circumferential surface 23. The first imaginary plane V21 and the second imaginary plane V22 are indicated in FIG. 5 by two-dot chain lines extending diagonally relative to the paper surface.

[0084] The magnetic path area of ​​the stator core 7 is likely to be increased by the first inclined surface 243 on each of the first side surface 24a and the second side surface 24b having the protruding portion 244. The reason for this is as follows. For example, in the case of core pieces in which the first side surface 24a and the second side surface 24b each have the first parallel surface 241, the second parallel surface 242, and the first inclined surface 243, and the first inclined surface 243 does not have the protruding portion 244, the following occurs. When the core pieces are arranged in an annular shape, if the first side surface 24a of the first core piece and the second side surface 24b of the second core piece that are adjacent in the circumferential direction of the stator core 7 are brought into contact with each other, the first corner of the first core piece and the second corner of the second core piece come into contact with each other. The first corner is the corner between the first side surface 24a and the inner circumferential surface 23. The second corner is the corner between the second side surface 24b and the inner circumferential surface 23. Therefore, the first side surface 24a of the first core piece 1 and the second side surface 24b of the second core piece cannot be in sufficient contact with each other. That is, the contact area between the first side surface 24a of the first core piece 1 and the second side surface 24b of the second core piece is reduced.

[0085] In contrast, the first side surface 24a of the core piece 1 has a first parallel surface 241, a second parallel surface 242, and a first inclined surface 243, and the first inclined surface 243 has a portion 244 that protrudes beyond the first imaginary plane V21. The second side surface 24b of the core piece 1 has a first parallel surface 241, a second parallel surface 242, and a first inclined surface 243, and the first inclined surface 243 has a portion 244 that protrudes beyond the second imaginary plane V22. When the core pieces 1 are arranged in an annular shape, even if the first side surface 24a of the first core piece 1 and the second side surface 24b of the second core piece 1 are brought into contact with each other, the first corner of the first core piece 1 and the second corner of the second core piece 1 can be prevented from coming into contact with each other. Therefore, the first side surface 24a of the first core piece 1 and the second side surface 24b of the second core piece 1 can be brought into sufficient contact with each other. That is, the contact area between the first side surface 24a of the first core piece 1 and the second side surface 24b of the second core piece 1 increases.

[0086] When constructing a stator core 7 provided in an axial gap type rotating electric machine 9 in which the core laminations 1 are of the DS / SR configuration, as described above, the first core laminations 1 and the second core laminations 1 adjacent in the circumferential direction of the stator core 7 are in contact with each other at the first side surface 24a of the second member 20 of the first core laminations 1 and the second side surface 24b of the second member 20 of the second core laminations 1. In this case, it is preferable that the first side surface 24a and the second side surface 24b of the core laminations 1 each have a step 240 that allows them to fit together, as shown in FIG. 3 . This makes it easier to increase the magnetic path area of ​​the stator core 7. The first core laminations 1 and the second core laminations 1 adjacent in the circumferential direction of the stator core 7 are fitted together at the step 240 of the first side surface 24a of the first protruding portion 211 of the second member 20 of the first core laminations 1 and the step 240 of the second side surface 24b of the second protruding portion 212 of the second member 20 of the second core laminations 1. Therefore, the first core laminations 1 and the second core laminations 1 can be brought into sufficient contact with each other, thereby increasing the contact area between adjacent core laminations 1 in the circumferential direction of the stator core 7. The step 240 of the first side surface 24a is provided on the first end face 26 side. The step 240 of the first side surface 24a is configured to become farther away from the first side surface 14a of the first member 10 as it moves from the first end face 26 to the second end face 27. On the other hand, the step 240 of the second side surface 24b is provided on the second end face 27 side. The step 240 of the second side surface 24b is configured to become farther away from the second side surface 14b of the first member 10 as it moves from the second end face 27 to the first end face 26.

[0087] Although not shown, the first side surface 24a of the core piece 1 may have at least one of a recess and a protrusion, rather than a step. The second side surface 24b may have at least one of a protrusion corresponding to the recess of the first side surface 24a and a recess corresponding to the protrusion of the first side surface 24a. In other words, both the first side surface 24a and the second side surface 24b may have unevenness. Furthermore, either the first side surface 24a or the second side surface 24b may have only a recess, and the other side surface may have only a protrusion. The number and shape of the recesses and protrusions are not particularly limited.

[0088] Although not shown, each of the first side surface 24a and the second side surface 24b of the core piece 1 may have a second inclined surface in contact with each other, rather than a step or unevenness. For example, the second inclined surface of the first side surface 24a may be inclined outward from the first end surface 26 toward the second end surface 27. And the second inclined surface of the second side surface 24b may be inclined outward from the second end surface 27 toward the first end surface 26.

[0089] When constructing a stator core 7 in an axial gap type rotating electric machine 9 having the core pieces 1 of SS / DR configuration, the core pieces 1 are arranged in an annular shape without contacting each other. In this case, the first side surface 24a and the second side surface 24b may not have any of the step 240, recessed portion, protruding portion, or second inclined surface that can fit together with each other.

[0090] The corners between the first side surface 24a and the first end surface 26 and the corners between the first side surface 24a and the second end surface 27 are rounded. The corners between the second side surface 24b and the first end surface 26 and the corners between the second side surface 24b and the second end surface 27 are rounded.

[0091] When the core pieces 1 are used to construct a stator core 7 for an axial gap rotating electric machine 9 having a DS / SR configuration, the first end surface 26 may be flat. When the core pieces 1 are used to construct a stator core 7 for an axial gap rotating electric machine 9 having a SS / DR configuration, the first end surface 26 may be flat or may be convex toward the Z1 direction. Such core pieces 1 can construct an axial gap rotating electric machine 9 with low noise and vibration. The reason for this is as follows. In an axial gap rotating electric machine 9 having an SS / DR configuration, a stator 8 and a rotor 90 are arranged facing each other, as shown in FIG. 14. As shown in FIG. 12, the stator 8 includes a stator core 7 and a coil 80. As shown in FIGS. 11 and 12, the stator core 7 is formed by arranging multiple core pieces 1 in an annular shape. The coil 80 is arranged in the first member 10 of each core piece 1, as shown in FIG. 12. If the first end faces 26 of the second members 20 of the core laminations 1 are formed in a convex shape, sudden changes in the magnetic flux of the magnets 95 of the rotor 90 that are received by the core laminations 1 in the axial gap type rotating electric machine 9 shown in Fig. 14 are easily suppressed. This makes it easy to reduce cogging torque. The small cogging torque makes it difficult for noise and vibration to increase.

[0092] It is preferable that the corners 28 between the first end face 26 and the inner peripheral surface 23 and the corners between the first end face 26 and the outer peripheral surface 22 are chamfered. These corners are less likely to be damaged when they are chamfered. These chamfers may be C-chamfered or R-chamfered.

[0093] [Third member] 1 and 3, the third member 30 is a plate-shaped member provided on the second end side in the Z-axis direction of the first member 10. The third member 30 forms a flange portion in either case where the core pieces 1 are used to construct a stator core 7 provided in an axial gap type rotating electric machine 9 of a DS / SR configuration or where the core pieces 1 are used to construct a stator core 7 provided in an axial gap type rotating electric machine 9 of a SS / DR configuration.

[0094] In this embodiment, the third member 30 has a trapezoidal plate shape. The trapezoidal plate shape is a trapezoidal cross section obtained by cutting the third member 30 along a plane perpendicular to the Z-axis direction. The cross section is uniform in the Z-axis direction. The third member 30 may also have a rectangular plate shape. For example, the core piece 1 may have a first member 10 in the shape of a trapezoidal column, and at least one of the second member 20 and the third member 30 in the shape of a rectangular plate.

[0095] As shown in FIGS. 1 to 3 , the third member 30 has a protruding portion 31. The protruding portion 31 protrudes outward from the circumferential surface 11 of the first member 10. The protruding portion 31 may protrude outward from the circumferential surface 11 of the first member 10 in a portion of the circumferential surface 11 of the first member 10, or may protrude outward from the circumferential surface 11 of the first member 10 over the entire circumferential circumference of the first member 10. In this embodiment, the protruding portion 31 has a first protruding portion 311 and a second protruding portion 312. The first protruding portion 311 protrudes toward a first direction side in the circumferential direction of the stator core 7. The second protruding portion 312 protrudes toward a second direction side in the circumferential direction of the stator core 7. Note that the protruding portion 31 may not have the first protruding portion 311 or the second protruding portion 312, and may have at least one of a portion protruding toward the X1 direction and a portion protruding toward the X2 direction. The protruding portion 31 may have a portion that protrudes in the X1 direction and a portion that protrudes in the X2 direction, in addition to the first protruding portion 311 and the second protruding portion 312. In this case, the protruding portion 31 is provided in an annular shape.

[0096] As described above, when the core pieces 1 are used to construct a stator core 7 to be provided in an axial gap type rotating electric machine 9 of DS / SR configuration, the protruding length of the first protruding portion 311 and the second protruding portion 312 of the third member 30 is shorter than the protruding length of the first protruding portion 311 and the second protruding portion 312 of the second member 20. As described above, when the core pieces 1 are used to construct a stator core 7 to be provided in an axial gap type rotating electric machine 9 of SS / DR configuration, the protruding length of the first protruding portion 311 and the second protruding portion 312 of the third member 30 may be set to the same as the protruding length of the first protruding portion 211 and the second protruding portion 212 of the second member 20.

[0097] 6, the third member 30 has an outer peripheral surface 32, an inner peripheral surface 33, a first side surface 34a, a second side surface 34b, a first end surface 36, and a second end surface 37. As described above, the positional relationship between the outer peripheral surface 32, the inner peripheral surface 33, the first side surface 34a, and the second side surface 34b is the same as the positional relationship between the respective surfaces in the first member 10. As described above, the positional relationship between the first end surface 36 and the second end surface 37 is the same as the positional relationship between the respective surfaces in the second member 20.

[0098] The outer peripheral surface 32 is continuous with the outer peripheral edge of the first side surface 34a, the outer peripheral edge of the second side surface 34b, the outer peripheral edge of the first end surface 36, and the outer peripheral edge of the second end surface 37. The outer peripheral surface 32 of the third member 30 is continuous with the outer peripheral surface 12 of the first member 10. The inner peripheral surface 33 is continuous with the inner peripheral edge of the first side surface 34a, the inner peripheral edge of the second side surface 34b, the inner peripheral edge of the first end surface 36, and the inner peripheral edge of the second end surface 37. The inner peripheral surface 33 of the third member 30 is continuous with the inner peripheral surface 13 of the first member 10. The first side surface 34a and the second side surface 34b are continuous with the outer peripheral surface 32 and the inner peripheral surface 33. The first end surface 36 is continuous with the outer peripheral surface 32, the first side surface 34a, the second side surface 34b, and the inner peripheral surface 33. The second end surface 37 is connected to the outer peripheral surface 32 , the first side surface 34 a , the second side surface 34 b , the inner peripheral surface 33 , and the peripheral surface 11 of the first member 10 .

[0099] The length between the first side surface 34a and the second side surface 34b at the outer peripheral surface 32 is longer than the length between the first side surface 34a and the second side surface 34b at the inner peripheral surface 33. The length between the first side surface 34a and the second side surface 34b at the outer peripheral surface 32 of the third member 30 is longer than the length between the first side surface 14a and the second side surface 14b at the outer peripheral surface 12 of the first member 10. The length between the first side surface 34a and the second side surface 34b at the outer peripheral surface 32 of the third member 30 is shorter than the length between the first side surface 24a and the second side surface 24b at the outer peripheral surface 22 of the second member 20. The length between the first side surface 34a and the second side surface 34b at the inner peripheral surface 33 of the third member 30 is the same as the length between the first side surface 14a and the second side surface 14b at the inner peripheral surface 13 of the first member 10. That is, the length between the first side surface 14a and the second side surface 14b on the inner surface 13 of the first member 10, the length between the first side surface 24a and the second side surface 24b on the inner surface 23 of the second member 20, and the length between the first side surface 34a and the second side surface 34b on the inner surface 33 of the third member 30 are all identical to each other.

[0100] In this embodiment, the outer peripheral surface 32 has a curved surface that is convex toward the X2 direction. The outer peripheral surface 32 may be configured as a flat surface. In this embodiment, the inner peripheral surface 33 has a curved surface that is convex toward the X1 direction. The inner peripheral surface 33 may have a curved surface that is convex toward the X2 direction, or may be configured as a flat surface. The bending radii of the outer peripheral surface 32 and the inner peripheral surface 33 may be the same or different from each other.

[0101] The bend radii of at least two of the outer peripheral surfaces 12, 22, and 32 may be the same. Of course, the bend radii of the outer peripheral surfaces 12, 22, and 32 may all be the same. The bend radii of the outer peripheral surfaces 12, 22, and 32 may all be different. The bend radii of the inner peripheral surfaces 13, 23, and 33 may at least be the same. Of course, the bend radii of the inner peripheral surfaces 13, 23, and 33 may all be the same. The bend radii of the inner peripheral surfaces 13, 23, and 33 may all be different.

[0102] Each of the first side surface 34a and the second side surface 34b has a first parallel surface 341, a second parallel surface 342, and a first inclined surface 343. The first parallel surfaces 341 of the first side surface 34a and the second side surface 34b are parallel to each other. The second parallel surfaces 342 of the first side surface 34a and the second side surface 34b are parallel to each other. The first parallel surface 341 of the first side surface 34a and the second parallel surface 342 of the first side surface 34a are parallel to each other. The first parallel surface 341 and the second parallel surface 342 are surfaces parallel to the X-axis direction of the core piece 1. The first parallel surface 341 is contiguous with the outer peripheral surface 32. The second parallel surface 342 is contiguous with the inner peripheral surface 33. The first inclined surface 343 is contiguous with the first parallel surface 341 and the second parallel surface 342.

[0103] As shown in FIG. 6 , the first inclination angle θ31 and the second inclination angle θ32 of the first inclined surface 343 are preferably, for example, 5° or more and 20° or less. When the first inclination angle θ31 and the second inclination angle θ32 are 5° or more and 20° or less, density variations in the core pieces 1 can be suppressed. The first inclination angle θ31 and the second inclination angle θ32 are preferably 5.5° or more and 18° or less, and particularly preferably 6° or more and 16° or less. The first inclination angle θ31 and the second inclination angle θ32 are preferably the same angle, but may be different. The first inclination angle θ31 refers to the angle between the first inclined surface 343 and an extension E31 of the first parallel surface 341 on the first side surface 34a. The second inclination angle θ32 refers to the angle between the first inclined surface 343 and an extension E32 of the first parallel surface 341 on the second side surface 34b.

[0104] At least two of the first inclination angles θ11, θ21, and θ31 may be the same. At least two of the second inclination angles θ12, θ22, and θ32 may be the same. Of course, the first inclination angles θ11, θ21, and θ31 may all be the same. The second inclination angles θ12, θ22, and θ32 may all be the same. Note that the first inclination angles θ11, θ21, and θ31 may all be different. The second inclination angles θ12, θ22, and θ32 may all be different.

[0105] The corners between the first side surface 34a and the first end surface 36 and the corners between the first side surface 34a and the second end surface 37 are rounded. The corners between the second side surface 34b and the first end surface 36 and the corners between the second side surface 34b and the second end surface 37 are rounded.

[0106] The first end surface 36 may be flat as shown by the solid line in FIG. 3 or may be convex toward the Z2 direction as shown by the two-dot chain line in FIG. 3 , regardless of whether the core laminations 1 are used to construct a stator core 7 for an axial gap rotating electric machine 9 of a DS / SR configuration or an axial gap rotating electric machine 9 of a SS / DR configuration. If the first end surface 36 is convex, an axial gap rotating electric machine 9 with low noise and vibration can be constructed. The reason for this is as follows. In an axial gap rotating electric machine 9, a stator 8 and a rotor 90 are arranged facing each other as shown in FIG. 13 or 14 . The stator 8 includes a stator core 7 and a coil 80 as shown in FIG. 12 . The stator core 7 is formed by arranging a plurality of core laminations 1 in an annular shape as shown in FIGS. 11 and 12 . The coil 80 is arranged in the first member 10 of each core lamination 1 as shown in FIG. 12 . As shown by the two-dot chain line in Fig. 3, the first end face 36 of the third member 30 of the core lamination 1 is provided in a convex shape, which tends to suppress sudden changes in the magnetic flux of the magnet 95 of the rotor 90 that is received by the core lamination 1 in the axial gap type rotating electric machine 9 shown in Figs. 13 and 14. This tends to reduce cogging torque. The small cogging torque also tends to prevent increases in noise and vibration.

[0107] It is preferable that the corner 38 between the first end face 36 and the inner peripheral surface 33 and the corner between the first end face 36 and the outer peripheral surface 32 are chamfered. These corners are less likely to be damaged when they are chamfered. These chamfers may be C-chamfered or R-chamfered.

[0108] [Seam] As shown in FIG. 3 , the first seam between the protruding portion 21 of the second member 20 and the circumferential surface 11 of the first member 10 and the second seam between the protruding portion 31 of the third member 30 and the circumferential surface 11 of the first member 10 are rounded. In this embodiment, the first seam includes the seam between the first protruding portion 211 of the second member 20 and the circumferential surface 11 of the first member 10, and the seam between the second protruding portion 212 of the second member 20 and the circumferential surface 11 of the first member 10. These seams are rounded. The second seam includes the seam between the first protruding portion 311 of the third member 30 and the circumferential surface 11 of the first member 10, and the seam between the second protruding portion 312 of the third member 30 and the circumferential surface 11 of the first member 10. These seams are rounded. By having each seam rounded, the core piece 1 is less likely to be damaged starting from the seam.

[0109] The bending radius of the first joint and the second joint is preferably 0.2 mm or more and 4.0 mm or less. When the bending radius of the first joint and the second joint is 0.2 mm or more, the load on the mold during manufacturing of the core laminations 1 is reduced. When the bending radius of the first joint and the second joint is 4.0 mm or less, it is easy to wind the coil 80 when constructing the stator 8 described below with reference to FIG. 12, and therefore it is easy to increase the number of turns of the coil 80. The bending radius of the first joint and the second joint is further preferably 0.3 mm or more and 3.0 mm or less, and particularly preferably 0.5 mm or more and 2.0 mm or less. The bending radius of the first joint and the second joint may be the same or different from each other.

[0110] [Area ratio] The total area of ​​the outer peripheral surfaces 12, 22, and 32 of each of the first member 10, the second member 20, and the third member 30 is preferably more than 1 time and not more than 4 times the total area of ​​the inner peripheral surfaces 13, 23, and 33 of each of the first member 10, the second member 20, and the third member 30. Core pieces 1 whose total area of ​​the outer peripheral surfaces 12, 22, and 32 is more than 1 time the total area of ​​the inner peripheral surfaces 13, 23, and 33 are easy to arrange in an annular shape and to construct the stator core 7. Core pieces 1 whose total area of ​​the outer peripheral surfaces 12, 22, and 32 is not more than 4 times the total area of ​​the inner peripheral surfaces 13, 23, and 33 are easy to manufacture. Since the ratio of the total area of ​​the inner peripheral surfaces 13, 23, and 33 is relatively high, the area extruded by the lower punch 55 is large when the core pieces 1 are extracted from the mold 5. Therefore, damage to the core pieces 1 when they are extracted from the mold 5 is easily suppressed. The total area of ​​the outer peripheral surfaces 12, 22, 32 is preferably 1.2 to 3.8 times the total area of ​​the inner peripheral surfaces 13, 23, 33, and more preferably 1.5 to 3.5 times.

[0111] [Material] The powder compact contains a plurality of soft magnetic particles. The powder compact is composed of an aggregate of the soft magnetic particles. The powder compact is obtained by compression molding soft magnetic powder containing a plurality of soft magnetic particles. The soft magnetic particles contain a plurality of iron-based particles made of pure iron or an iron-based alloy. Pure iron refers to iron with a purity of 99% by mass or more. The iron-based alloy contains at least one element of Si (silicon) and Al (aluminum), with the remainder consisting of Fe and inevitable impurities. The iron-based alloy may be at least one selected from the group consisting of an Fe-Si alloy, an Fe-Al alloy, and an Fe-Si-Al alloy. An example of an Fe-Si alloy is silicon steel. An example of an Fe-Si-Al alloy is sendust. Since the above materials are relatively soft, the soft magnetic particles are easily deformed during molding of the powder compact. Therefore, the core piece 1 has high density and excellent dimensional accuracy. The powder compact is preferably composed of an aggregate of a plurality of coated soft magnetic particles having insulating coatings on the surfaces of the soft magnetic particles. That is, the powder compact is preferably one obtained by compression molding of a coated soft magnetic powder having a plurality of coated soft magnetic particles. If an insulating coating is formed, the insulating coating can easily ensure electrical insulation between particles. Therefore, iron loss of the powder compact caused by eddy current loss can be reduced. The soft magnetic particles are as described above. Examples of insulating coatings include phosphate coatings and silica coatings.

[0112] Relative Density The relative density of the powder compact is preferably 85% or more. A powder compact with a relative density of 85% or more has excellent magnetic properties such as saturation magnetic flux density, and mechanical properties such as strength. The relative density of the powder compact is more preferably 90% or more, and particularly preferably 93% or more. The relative density of the powder compact may be less than 100%. "Relative density" refers to the ratio (%) of the actual density of the powder compact to the true density of the soft magnetic particles that make up the powder compact.

[0113] [Relative Density Difference] Of the first, second, and third portions of the core piece 1, the difference in relative density between the first and second portions and the third portion is preferably 5.0% or less. Because the difference in relative density is small, the core piece 1 has substantially uniform physical properties, such as magnetic properties, within the core piece 1. The smaller the difference in relative density between the first and second portions and the third portion, the more preferable. The difference in relative density between the first and second portions and the third portion is more preferably 4.0% or less, and particularly preferably 3.0% or less. Here, as shown in FIG. 2 , of the portions obtained by dividing the core piece 1 into three by an imaginary plane Va along the second parallel plane of the first side surface and an imaginary plane Vb along the second parallel plane of the second side surface, the portion on the first circumferential direction side is referred to as the first portion, the portion on the second circumferential direction side is referred to as the second portion, and the portion between the first and second portions is referred to as the third portion.

[0114] Of the first member 10, the second member 20, and the third member 30, it is preferable that the difference in relative density between the member with the highest relative density and the member with the lowest relative density be 5.0% or less. Because the difference in relative density is small in this core piece 1, physical properties such as magnetic properties are substantially uniform within the core piece 1. The smaller the difference in relative density between the member with the highest relative density and the member with the lowest relative density, the more preferable. The difference in relative density between the member with the highest relative density and the member with the lowest relative density is more preferably 4.0% or less, and particularly preferably 3.0% or less.

[0115] It is preferable that the difference in relative density between the first and second regions and the third region is 5.0% or less, and that the difference in relative density between the member with the highest relative density and the member with the lowest relative density is 5.0% or less.

[0116] [Manufacturing method] The core piece 1 according to the first embodiment can be manufactured by a core piece manufacturing method including a filling step and a molding step. In the filling step, raw material powder is filled into the cavity of a die 5. In the molding step, the raw material powder in the cavity is compression molded. First, the die 5 will be described with reference to Figs. 7 to 10, and then each step will be described.

[0117] [Mold] The mold 5 includes a die 50, an upper punch 54, and a lower punch 55. The die 50 and the lower punch 55 form a cavity into which the raw material powder is filled.

[0118] (Thailand) The die 50 has a mold hole 50h. An upper punch 54 and a lower punch 55 are arranged in the mold hole 50h so as to face each other. The inner peripheral shape of the mold hole 50h corresponds to the shape of the core piece 1. The upper punch 54 can be driven independently in the vertical direction relative to the die 50. The lower punch 55 can be driven independently in the vertical direction relative to the die 50.

[0119] The mold cavity 50h has a first hole portion 51 shown in Figures 7 and 8, a second hole portion 52 shown in Figures 7 and 9, and a third hole portion 53 shown in Figures 7 and 10. Figure 7 shows the opening edge of the mold cavity 50h of the die 50 on the upper punch 54 side. For ease of explanation, Figure 7 hatches the die 50. Figures 8 to 10 are cross-sectional views showing the state in which the raw material powder filled in the cavity is pressure-molded by the upper punch 54 and the lower punch 55. The cross-sectional view of Figure 8 is cut at a position indicated by the VIII-VIII cutting line in Figure 7. The cross-sectional view of Figure 9 is cut at a position indicated by the IX-IX cutting line in Figure 7. The cross-sectional view of Figure 10 is cut at a position indicated by the XX cutting line in Figure 7.

[0120] The first hole portion 51 has an inner peripheral surface that forms the first side surface 14a and the second side surface 14b of the first member 10. The second hole portion 52 has an inner peripheral surface that forms the first side surface 24a, the second side surface 24b, the first end surface 26, and the second end surface 27 of the second member 20. The third hole portion 53 has an inner peripheral surface that forms the first side surface 34a, the second side surface 34b, the first end surface 36, and the second end surface 37 of the third member 30. The first hole portion 51, the second hole portion 52, and the third hole portion 53 are formed continuously in a direction perpendicular to the direction in which the upper punch 54 and the lower punch 55 face each other. Specifically, the second hole portion 52 is connected to a first end of the first hole portion 51 in the perpendicular direction. The third hole portion 53 is connected to a second end of the first hole portion 51 in the perpendicular direction.

[0121] The first hole portion 51 includes a first straight portion 511, a second straight portion 512, and a tapered portion 513. The first straight portion 511, the tapered portion 513, and the second straight portion 512 are formed in a continuous sequence from the upper punch 54 side toward the lower punch 55 side. Similarly, the second hole portion 52 includes a first straight portion 521, a second straight portion 522, and a tapered portion 523. The first straight portion 521, the tapered portion 523, and the second straight portion 522 are formed in a continuous sequence from the upper punch 54 side toward the lower punch 55 side. Similarly, the third hole portion 53 includes a first straight portion 531, a second straight portion 532, and a tapered portion 533. The first straight portion 531, the tapered portion 533, and the second straight portion 532 are formed in a continuous sequence from the upper punch 54 side toward the lower punch 55 side. The first straight portions 511, 521, 531 form the outer peripheral surface side portion of the core piece 1. The second straight portions 512, 522, 532 form the inner peripheral surface side portion of the core piece 1. The tapered portions 513, 523, 533 form the portion between the outer peripheral surface side and the inner peripheral surface side of the core piece 1.

[0122] (upper punch) The upper punch 54 has a first upper punch portion 541 shown in FIG. 8, a second upper punch portion 542 shown in FIG. 9, and a third upper punch portion 543 shown in FIG. 10. The first upper punch portion 541 has a first lower end surface 541e. The first lower end surface 541e forms the outer peripheral surface 12 of the first member 10. The second upper punch portion 542 has a second lower end surface 542e. The second lower end surface 542e forms the outer peripheral surface 22 of the second member 20. The third upper punch portion 543 has a third lower end surface 543e. The third lower end surface 543e forms the outer peripheral surface 32 of the third member 30. The first upper punch portion 541, the second upper punch portion 542, and the third upper punch portion 543 may be formed in a continuous manner, or may be formed independently of each other so as to be able to move up and down independently. When the first upper punch portion 541, the second upper punch portion 542, and the third upper punch portion 543 are formed continuously, the first lower end surface 541e, the second lower end surface 542e, and the third lower end surface 543e are formed continuously. The shape of the first lower end surface 541e corresponds to the shape of the outer peripheral surface 12 of the first member 10. The shape of the second lower end surface 542e corresponds to the shape of the outer peripheral surface 22 of the second member 20. The shape of the third lower end surface 543e corresponds to the shape of the outer peripheral surface 32 of the third member 30.

[0123] (lower punch) The lower punch 55 has a first lower punch portion 551 shown in FIG. 8, a second lower punch portion 552 shown in FIG. 9, and a third lower punch portion 553 shown in FIG. 10. The first lower punch portion 551 has a first upper end surface 551e. The first upper end surface 551e forms the inner circumferential surface 13 of the first member 10. The second lower punch portion 552 has a second upper end surface 552e. The second upper end surface 552e forms the inner circumferential surface 23 of the second member 20. The third lower punch portion 553 has a third upper end surface 553e. The third upper end surface 553e forms the inner circumferential surface 33 of the third member 30. The first lower punch portion 551, the second lower punch portion 552, and the third lower punch portion 553 may be formed in a continuous manner, or may be formed independently of each other so as to be able to move up and down independently. When the first lower punch portion 551, the second lower punch portion 552, and the third lower punch portion 553 are formed continuously, the first upper end surface 551e, the second upper end surface 552e, and the third upper end surface 553e are formed continuously. The shape of the first upper end surface 551e corresponds to the shape of the inner circumferential surface 13 of the first member 10. The shape of the second upper end surface 552e corresponds to the shape of the inner circumferential surface 23 of the second member 20. The shape of the third upper end surface 553e corresponds to the shape of the inner circumferential surface 33 of the third member 30.

[0124] [Filling process] The cavity formed by the die 50 and the lower punch 55 is filled with raw material powder. The aforementioned soft magnetic powder or coated soft magnetic powder can be used as the raw material powder. In addition to the soft magnetic powder or coated soft magnetic powder, the raw material powder may contain a binder and a lubricant. A lubricant may be applied to the inner peripheral surface of the die hole 50h of the die 50.

[0125] [Molding process] The raw material powder in the cavity is compression-molded by an upper punch 54 and a lower punch 55. The direction in which the raw material powder is compressed is along the radial direction of the stator core 7. The higher the pressure during compression molding, the higher the relative density of the core pieces 1 produced. The pressure may be, for example, 700 MPa or more, and may further be 980 MPa or more.

[0126] [Other processes] After the compacting step, a heat treatment may be performed as necessary. For example, the heat treatment can remove distortion, thereby producing a low-loss core piece 1. Alternatively, the heat treatment can remove binders and lubricants. When the raw material powder contains the coated soft magnetic particles described above, the heat treatment temperature is preferably equal to or lower than the decomposition temperature of the insulating coating.

[0127] [Action and effect] The core piece 1 of this embodiment is made up of a powder compact in which the first member 10, the second member 20, and the third member 30 are integrally molded, and therefore has excellent productivity.

[0128] Second Embodiment [Stator core] A stator core 7 according to a second embodiment will be described with reference to FIG. 11 . The stator core 7 of this embodiment has a plurality of core laminations 1 arranged in an annular shape. Each of the plurality of core laminations 1 is the core lamination 1 according to the first embodiment. The plurality of core laminations 1 are combined in an annular shape such that, among the core laminations 1 adjacent in the circumferential direction, the step 240 on the first side surface 24a of the second member 20 of the first core lamination 1 and the step 240 on the second side surface 24b of the second member 20 of the second core lamination 1 fit together. This stator core 7 is used in an axial gap type rotating electric machine 9 of DS / SR configuration shown in FIG. 13 .

[0129] It is preferable that the variation in the length between the face on the first end side and the face on the second end side in the Z-axis direction of each of the multiple core pieces 1 is 0.1 mm or less. The length between the face on the first end side and the face on the second end side in the Z-axis direction is the maximum length between the first end face 26 of the second member 20 and the first end face 36 of the third member 30.

[0130] If the variation in length between the first end face 26 of the second member 20 and the first end face 36 of the third member 30 in each of the multiple core laminations 1 is 0.1 mm or less, the variation in length is very small. Therefore, the stator core 7 can be used to construct an axial gap type rotating electric machine 9 with low noise and vibration. The reason for this is as follows. In the axial gap type rotating electric machine 9, the stator 8 and the rotor 90 are arranged facing each other, as shown in FIG. 13 . The small variation in the length of the stator core 7 reduces the variation in the gap between the stator 8 and the rotor 90. The small variation in the gap reduces torque ripple. The small torque ripple reduces noise and vibration. The variation in length is determined as follows. For each core lamination 1, the length from the first end face 26 of the second member 20 to the first end face 36 of the third member 30 is measured. This length is the maximum length of the core lamination 1 along the Z-axis direction. The difference between the maximum and minimum values ​​of the length for each of the multiple core pieces 1 is calculated. This difference is defined as the variation in the length. The variation in the length between the first end face 26 of the second member 20 and the first end face 36 of the third member 30 for each of the multiple core pieces 1 is further preferably 0.05 mm or less, and particularly preferably 0.01 mm or less.

[0131] [Action and effect] The stator core 7 of this embodiment has excellent productivity because the plurality of core pieces 1 that constitute the stator core 7 are made up of the core pieces 1 of the first embodiment, which has excellent productivity.

[0132] Third Embodiment [Stator] A stator 8 according to a third embodiment will be described with reference to Fig. 12. The stator 8 of this embodiment includes a stator core 7 and a coil 80. The stator core 7 according to the second embodiment can be used as the stator core 7. The coil 80 is wound around the first member 10 in each core piece 1 of the stator core 7. This stator 8 is used in an axial gap type rotating electric machine 9 of DS / SR configuration shown in Fig. 13.

[0133] Each coil 80 has a cylindrical portion formed by winding a wire. The winding is made of a coated round wire. The coated round wire has a round wire conductor and an edge coating provided around the conductor. Note that FIG. 12 shows only the cylindrical portion of each coil 80 in a simplified manner, and both ends of the winding are not shown. The stator core 7 can be produced by winding a wire around the outside of the first member 10 of each core piece 1.

[0134] [Action and effect] The stator 8 according to the third embodiment is excellent in productivity because it includes the stator core 7 of the second embodiment, which is excellent in productivity.

[0135] Fourth Embodiment [Rotating Electric Machines] A rotating electric machine 9 according to a fourth embodiment will be described with reference to FIG. 13. FIG. 13 is a cross-sectional view taken along a plane parallel to the rotating shaft 91 of the rotating electric machine 9 and passing through the circumferential center of the core laminations 1. This also applies to FIG. 14, which will be referred to in a fifth embodiment described later. The rotating electric machine 9 according to this embodiment is an axial gap type rotating electric machine. The rotating electric machine 9 according to this embodiment is a DS / SR type including one rotor 90 and two stators 8. That is, in the rotating electric machine 9, the rotor 90 and the stators 8 are arranged axially opposite each other. One rotor 90 is assembled so as to be sandwiched between the two stators 8. The stator 8 according to the third embodiment described above can be used for each stator 8. The rotating electric machine 9 can be used as a motor or a generator. The rotating electric machine 9 includes a case 92.

[0136] The case 92 has a cylindrical internal space that houses the stator 8 and the rotor 90. The case 92 includes a cylindrical portion 921 and two plates 922. The cylindrical portion 921 surrounds the outer peripheries of the stator 8 and the rotor 90. A plate 922 is disposed on each end of the cylindrical portion 921. The two plates 922 are fixed to both end surfaces of the cylindrical portion 921 so as to sandwich the stator 8 and the rotor 90 from both sides in the axial direction. Both plates 922 have a through hole in their center. A bearing 93 is provided in the through hole. The rotating shaft 91 is inserted into the through hole via this bearing 93. The rotating shaft 91 passes through the case 92.

[0137] The rotor 90 includes a magnet 95 and a rotor body. In this embodiment, the rotor 90 is a flat-plate-shaped member. The number of magnets 95 may be multiple, as in this embodiment, or may be one, unlike this embodiment. When the number of magnets 95 is multiple, the specific number of magnets 95 may be the same as the number of core pieces 1. The multiple magnets 95 are arranged at equal intervals in the circumferential direction of the rotor body. In this embodiment, each magnet 95 is flat and has a planar shape corresponding to the planar shape of the first end surface 36 of the third member 30 in each core piece 1. Note that each magnet 95 may be in the shape of a convex lens having a convex surface facing the stator 8. When there is only one magnet 95, the magnet 95 is annular. Each magnet 95 has south and north poles arranged alternately in the circumferential direction. The rotor body supports the multiple magnets 95. The rotor body is an annular-shaped member. The rotor body is rotatably supported by a rotating shaft 91. The magnets 95 are arranged at equal intervals around the circumferential direction of the rotor body. Each magnet 95 is magnetized in the axial direction of the rotating shaft 91. The magnetization directions of adjacent magnets 95 around the circumferential direction of the rotor body are opposite to each other. The rotating magnetic field generated by the stator 8 causes the magnets 95 to repeatedly attract and repel each core piece 1, causing the rotor 90 to rotate.

[0138] The stator 8 is disposed so that the first end face 36 of the third member 30 in each core lamination 1 faces the magnet 95 of the rotor 90. When the rotor 90 rotates, the first end face 36 of the third member 30 in each core lamination 1 receives magnetic flux from the rotating magnet 95. If the first end face 36 of the third member 30 in each core lamination 1 is configured in a convex shape as described above, as shown in FIG. 3 , the noise and vibration of the rotating electric machine 9 can be reduced. The reason for this is as follows. By providing the first end face 36 of the third member 30 in each core lamination 1 in a convex shape, sudden changes in the magnetic flux of the magnet 95 of the rotor 90 received by each core lamination 1 are easily suppressed. Therefore, cogging torque is easily reduced. Since the cogging torque is small, noise and vibration are less likely to increase.

[0139] [Action and effect] The rotary electric machine 9 according to the fourth embodiment is excellent in productivity since it includes the stator 8 according to the third embodiment, which is excellent in productivity.

[0140] Fifth Embodiment [Rotating Electric Machines] A rotating electric machine 9 according to the fifth embodiment will be described with reference to FIG. 14. The rotating electric machine 9 of this embodiment is an axial gap type rotating electric machine. The rotating electric machine 9 of this embodiment differs from the rotating electric machine 9 of the fourth embodiment mainly in that it is an SS / DR type having two rotors 90 and one stator 8. That is, in the rotating electric machine 9, the rotor 90 and the stator 8 are arranged facing each other in the axial direction. One stator 8 is assembled so as to be sandwiched between the two rotors 90. The following description will focus on the differences from the fourth embodiment. Description of the same configuration as the fourth embodiment will be omitted.

[0141] Each rotor 90 includes a rotor body, a plurality of magnets 95, and a back yoke 98. The rotor body and the plurality of magnets 95 are the same as those in the fourth embodiment. The back yoke 98 is provided between the rotor 90 and the plate 922. The back yoke 98 is a flat plate-shaped member. The back yoke 98 is made of a powder compact similar to the core lamination 1 described above, or a laminated steel plate.

[0142] The stator 8 includes a plurality of core laminations 1 arranged in an annular shape, a coil 80 wound around the first member 10 of each core lamination 1, and a support member that holds the plurality of core laminations 1. The support member is not shown. Each core lamination 1 has the same configuration as the second member 20 and the third member 30. That is, in each core lamination 1, the protrusion amounts of the first protrusion 211 and the second protrusion 212 on the second member 20 are the same as the protrusion amounts of the first protrusion 311 and the second protrusion 312 on the third member 30. Furthermore, the first side surface 24a of the first protrusion 211 and the second side surface 24b of the second protrusion 212 on the second member 20 do not have the steps described above. The coil 80 is the same as that of the third embodiment. The holder holds the plurality of core laminations 1 so that the core laminations 1 are spaced equally apart. This holder prevents circumferentially adjacent core laminations 1 from contacting each other.

[0143] [Action and effect] Like the rotating electric machine 9 of the fourth embodiment, the rotating electric machine 9 of the fifth embodiment is provided with the stator 8 which is highly productive, and therefore is highly productive.

[0144] The present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. For example, a rotating electric machine may include one rotor and one stator. [Explanation of symbols]

[0145] 1 core piece 10 First member 11 peripheral surface, 12 outer peripheral surface, 13 inner peripheral surface 14a first side, 14b second side 141 first parallel plane, 142 second parallel plane, 143 first inclined plane 20 Second member 21 protrusion, 211 first protrusion, 212 second protrusion 22 outer circumferential surface, 23 inner circumferential surface, 24a first side, 24b second side 240 steps 241 first parallel plane, 242 second parallel plane, 243 first inclined plane, 244 protruding part 26 First end face, 27 Second end face, 28 Corner part 30 Third member 31 protrusion, 311 first protrusion, 312 second protrusion 32 outer circumferential surface, 33 inner circumferential surface 34a first side, 34b second side 341 first parallel plane, 342 second parallel plane, 343 first inclined plane 36 first end face, 37 second end face, 38 corner 5. Mold 50 die, 50h hole 51 First hole 511 First straight section, 512 Second straight section, 513 Tapered section 52 Second hole 521 First straight section, 522 Second straight section, 523 Tapered section 53 Third hole 531 first straight section, 532 second straight section, 533 tapered section 54 Upper Punch 541 first upper punch portion, 541e first lower end surface 542 second upper punch portion, 542e second lower end surface 543 third upper punch portion, 543e third lower end surface 55 Lower Punch 551 first lower punch portion, 551e first upper end surface 552 second lower punch portion, 552e second upper end surface 553 third lower punch portion, 553e third upper end surface 7 stator core, 8 stator, 80 coil 9 Rotating Electric Machines 90 rotor, 91 rotating shaft, 92 case 921 Cylindrical part, 922 Plate 93 bearing, 95 magnet, 98 back yoke E11, E12, E21, E22, E31, E32 extension surface Va, Vb virtual surface, V21 first virtual surface, V22 second virtual surface θ11, θ21, θ31 First tilt angle θ12, θ22, θ32 Second inclination angle

Claims

1. A powder compact used in an axial gap type rotating electric machine, an outer peripheral surface disposed on the outer peripheral side of the powder compact; an inner peripheral surface disposed on the inner peripheral side of the powder compact; a first side surface disposed on a first direction side in the circumferential direction of the powder compact and connected to the outer circumferential surface and the inner circumferential surface; a second side surface disposed on a second direction side in the circumferential direction of the powder compact and connected to the outer circumferential surface and the inner circumferential surface, a length between the first side surface and the second side surface on the outer peripheral surface is longer than a length between the first side surface and the second side surface on the inner peripheral surface, Each of the first side surface and the second side surface is a first parallel surface connected to the outer circumferential surface; a second parallel surface continuous with the inner circumferential surface; a first inclined surface connected to the first parallel surface and the second parallel surface, the first parallel surface of the first side surface and the first parallel surface of the second side surface are parallel to each other, the second parallel surface of the first side surface and the second parallel surface of the second side surface are parallel to each other, the first parallel surface of the first side surface and the second parallel surface of the first side surface are parallel to each other; Powder compact.

2. an angle between an extension of the first parallel surface of the first side surface and the first inclined surface is greater than or equal to 5° and less than or equal to 20°; The powder molded body according to claim 1 , wherein an angle formed between an extension of the first parallel surface of the second side surface and the first inclined surface is equal to or greater than 5° and equal to or less than 20°.

3. The outer circumferential surface has a curved surface that is convex toward the outer circumferential side, 3. The powder molded body according to claim 1, wherein the inner peripheral surface has a curved surface that is convex toward the inner peripheral side.

4. 3. The powder molded body according to claim 1, wherein, among the three regions obtained by dividing the powder molded body into three parts by an imaginary plane along the second parallel plane of the first side surface and an imaginary plane along the second parallel plane of the second side surface, a difference in relative density between a first region on a first direction side in the circumferential direction and a second region on a second direction side in the circumferential direction, and a third region between the first region and the second region is 5.0% or less.

5. 3. The powder compact according to claim 1, wherein the powder compact has a relative density of 85% or more.

6. the powder compact is composed of an aggregate of a plurality of coated soft magnetic particles having insulating coatings on the surfaces of the soft magnetic particles, 3. The powder compact according to claim 1, wherein the soft magnetic particles are iron-based particles made of at least one metal selected from the group consisting of pure iron, an Fe—Si-based alloy, an Fe—Al-based alloy, and an Fe—Si—Al-based alloy.

7. A core of an axial gap type rotating electrical machine, a plurality of powder compacts arranged in an annular shape; A member constituting each of the plurality of powder molded bodies is the powder molded body according to claim 1 or 2. core.

8. A stator of an axial gap type rotating electric machine, A core according to claim 7; a coil disposed on the core, Stator.

9. An axial gap type rotating electric machine including a rotor and a stator, the rotor and the stator being arranged to face each other in an axial direction, The stator is a stator according to claim 8. Rotating electric motor.

Images