Iron core, stator, and rotating electric machine

Abstract

An iron core used in an axial gap type rotating electric machine, the iron core comprising: an annular plate-shaped yoke part; and a plurality of columnar tooth portions disposed at intervals in the circumferential direction of the yoke portion, the yoke portion having: an outer circumferential surface; an inner peripheral surface; a planar first surface connecting the outer peripheral surface and the inner peripheral surface; and a plurality of recessed portions connected to the first surface, each of the plurality of tooth portions having an outer peripheral surface protruding in the axial direction of the yoke portion with respect to the first surface, the plurality of recessed portions being connected to at least a portion of the outer peripheral surface of each of the plurality of tooth portions in the circumferential direction, and each of the plurality of tooth portions having an outer peripheral surface protruding in the axial direction of the yoke portion with respect to the first surface. The shortest distance between at least one of the outer peripheral edge of the first surface and the inner peripheral edge of the first surface and the outer peripheral surface of each of the plurality of tooth portions is all less than or equal to 4 mm, and the yoke portion and the plurality of tooth portions are configured from an integrally molded powder compact.

Description

[0001] This application is a divisional application of Chinese National Application No. 201980067581.1 (Core, Stator and Rotating Electrical Machine) filed on December 13, 2019, the contents of which are quoted below. Technical Field

[0002] This invention relates to iron cores, stators, and rotating electric machines.

[0003] This application claims priority based on Japanese Patent Application No. 2018-236767, filed on December 18, 2018, and incorporates all the contents set forth in the aforementioned Japanese application. Background Technology

[0004] As a core used in axially spaced rotary electric machines, the pressed powder core of Patent Document 1 is known. The pressed powder core of Patent Document 1 has a fan-shaped yoke and teeth protruding from the yoke. The yoke and teeth are integrally formed. The outer and inner peripheries of the yoke are spaced at the same intervals from the teeth.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-229191 Summary of the Invention

[0006] The iron core involved in this invention is used in axially spaced rotary motors. The iron core has the following characteristics: A ring-shaped yoke; and Multiple columnar teeth are arranged circumferentially spaced apart from each other on the yoke. The yoke has: outer peripheral surface; Inner circumference; A planar first surface that connects the outer peripheral surface and the inner peripheral surface; and Multiple recesses, which are connected to the first surface, Each of the plurality of teeth has an outer peripheral surface that protrudes axially from the first surface in the yoke. The plurality of recesses are respectively connected to at least a circumferential portion of the outer peripheral surface of each of the plurality of teeth. The shortest distance between at least one of the outer peripheral edge and the inner peripheral edge of the first surface and the respective outer peripheral surface of the plurality of teeth is all less than or equal to 4 mm. The yoke and the plurality of teeth are formed by an integrally molded powder body.

[0007] The stator involved in this invention, It is the stator of an axially backlash type rotary electric machine. The stator has the following characteristics: The iron core involved in this invention; and A coil, which is disposed in each of the plurality of teeth of the iron core.

[0008] The rotary electric motor of the present invention has a rotor and a stator, and is an axially spaced rotary electric motor in which the rotor and the stator are arranged axially opposite each other. In this rotary motor, The stator is the stator involved in this invention. Attached Figure Description

[0009] Figure 1 This is a schematic perspective view of the iron core involved in Embodiment 1.

[0010] Figure 2 This is a schematic top view showing a portion of the iron core involved in Embodiment 1.

[0011] Figure 3 It means in Figure 2 A rough composite sectional view of the iron core cut off at line A-B-C-D.

[0012] Figure 4 It is Figure 3 An enlarged view showing the area near the concave part inside the dashed circle.

[0013] Figure 5 It means in Figure 2 A rough cross-sectional view of the iron core cut at the (V)-(V) cut line.

[0014] Figure 6 This is a schematic cross-sectional view showing the mold for manufacturing the iron core according to Embodiment 1.

[0015] Figure 7 This is a schematic perspective view showing the iron core involved in Embodiment 2.

[0016] Figure 8 This is a schematic top view showing a portion of the iron core involved in Embodiment 2.

[0017] Figure 9 This is a schematic partial cross-sectional view showing the mold for manufacturing the iron core according to Embodiment 2 and the iron core of Sample No.1.

[0018] Figure 10 This is a schematic perspective view of the first punch of the mold for manufacturing the iron core according to Embodiment 2 and the iron core of Sample No.1.

[0019] Figure 11 This is a perspective view showing a schematic representation of the stator involved in Embodiment 3.

[0020] Figure 12This is a schematic cross-sectional view showing the rotary electric motor involved in Embodiment 4.

[0021] Figure 13 This is a schematic perspective view of the first punch of the mold used to form the iron core of sample No. 101. Detailed Implementation

[0022] [The problem to be solved by the present invention]

[0023] There is a desire for a high-density iron core with a large ratio of tooth size to yoke size. However, the optimal shape and manufacturing method for such a core have not yet been fully studied.

[0024] Therefore, one of the objectives of this invention is to provide a high-density iron core with a large ratio of tooth size to yoke size and excellent productivity.

[0025] In addition, one of the objectives of this invention is to provide a stator for a rotary electric machine that can be constructed with excellent magnetic properties and productivity.

[0026] Furthermore, one of the objectives of this invention is to provide a rotary motor with excellent magnetic properties and productivity.

[0027] [Effects of the Invention]

[0028] The iron core involved in this invention has high density and a large ratio of tooth size to yoke size, resulting in excellent productivity.

[0029] The stator of this invention can be used to construct a rotating electric motor with excellent magnetic properties and productivity.

[0030] The rotary electric motor involved in this invention has excellent magnetic properties and productivity.

[0031] Description of Embodiments of the Invention

[0032] First, embodiments of the present invention will be described.

[0033] (1) One aspect of the present invention relates to an iron core used in an axially gap type rotary electric motor. The iron core has the following characteristics: A ring-shaped yoke; and Multiple columnar teeth are arranged circumferentially spaced apart from each other on the yoke. The yoke has: outer peripheral surface; Inner circumference; A planar first surface that connects the outer peripheral surface and the inner peripheral surface; and Multiple recesses, which are connected to the first surface, Each of the plurality of teeth has an outer peripheral surface that protrudes axially from the first surface in the yoke. The plurality of recesses are respectively connected to at least a circumferential portion of the outer peripheral surface of each of the plurality of teeth. The shortest distance between at least one of the outer peripheral edge and the inner peripheral edge of the first surface and the respective outer peripheral surface of the plurality of teeth is all less than or equal to 4 mm. The yoke and the plurality of teeth are formed by an integrally molded powder body.

[0034] The size of the teeth in the aforementioned iron core is proportionally large to the size of the yoke. This is because the aforementioned shortest distance satisfies the aforementioned range.

[0035] Furthermore, the aforementioned iron core exhibits high density and excellent productivity. This is because, when manufacturing an iron core with an annular plate-shaped yoke and multiple columnar teeth integrated by compression molding using a mold, and where the aforementioned minimum distance meets the aforementioned range, the aforementioned recess is formed simultaneously, thus preventing mold damage even when the molding pressure is increased. As detailed later, this recess is formed by transferring the shape of the protrusion at the end face of the punch during compression molding. When the punch compresses the raw material powder for the iron core, the deformation of the punch is suppressed by the anchoring effect generated by the protrusion entering the raw material powder. Therefore, even when the molding pressure is increased to achieve high density in the iron core, the stress generated at the corners of the punch is reduced. Consequently, punch breakage is less likely. The aforementioned minimum distance is based on the length between the outer and inner periphery of the punch's end face and the inner periphery of the punch's hole, as detailed later. Therefore, when manufacturing an iron core with the aforementioned minimum distance meeting the aforementioned range, the aforementioned length of the punch is small. Therefore, if the aforementioned recess is not formed when manufacturing the iron core with the aforementioned minimum distance satisfying the aforementioned range, the punch is more prone to deformation. In contrast, by forming the aforementioned recess when manufacturing the iron core with the aforementioned minimum distance satisfying the aforementioned range, the deformation of the punch is suppressed as described above.

[0036] Furthermore, the aforementioned iron core allows magnetic flux to flow smoothly from each tooth to the yoke. This is because the yoke and each tooth are integrally formed, thus preventing gaps that could become magnetic gaps between the yoke and the teeth.

[0037] (2) As one method of the aforementioned iron core, one can cite the following: The outer peripheral surface of each of the plurality of teeth has: A first region, which faces the outer peripheral surface of the tooth adjacent to one circumferential side of the yoke; and The second region faces the outer peripheral surface of the tooth adjacent to the yoke on the other side in the circumferential direction. Each of the plurality of recesses has a portion connected to the first region and a portion connected to the second region.

[0038] The aforementioned iron core facilitates high-density production and increased core productivity. This is because the aforementioned iron core exhibits a high degree of stress reduction at the corners of the punch.

[0039] (3) As one method of the aforementioned iron core, the following can be cited: The plurality of recesses are circumferentially connected to the outer peripheral surfaces of the plurality of teeth.

[0040] The aforementioned iron core facilitates further increases in core density and productivity. This is because the aforementioned iron core exhibits a greater reduction in stress at the corners of the punch.

[0041] (4) As one method of the aforementioned iron core, the following can be cited: Each of the plurality of recesses has an inclined surface that deepens as it approaches the outer peripheral surface of each of the plurality of teeth from the first surface.

[0042] The aforementioned core allows for further increases in core density and productivity. The concave portion with an inclined surface is formed using a punch with a protrusion having an inclined surface. The protrusion of the punch has an inclined surface, thus, as detailed later, resulting in a greater reduction in stress at the corners of the punch.

[0043] (5) As one method of the aforementioned iron core, the following can be cited: The yoke has a cutout portion, which, compared to the teeth, is located on at least one of the outer peripheral surface and the inner peripheral surface of the yoke. The cut portion opens on at least one of the outer peripheral surface and the inner peripheral surface of the yoke.

[0044] The aforementioned iron core facilitates the construction of the rotary motor described later. This is because the cutout portion of the iron core can be used for positioning the iron core within the housing of the rotary motor. Furthermore, the aforementioned iron core facilitates the attachment and extraction of the ends of the coil windings in the stator through the cutout portion.

[0045] (6) As one embodiment of the aforementioned iron core having the aforementioned cut portion, an example can be given, The cut portion opens at least on one of the outer peripheral surface and the inner peripheral surface of the yoke, corresponding to the portion between adjacent teeth.

[0046] The aforementioned iron core is easily positioned within the housing of the rotating electric motor. Furthermore, the iron core facilitates the clamping of the winding ends. Moreover, the design of the shape and size of the cutout in the iron core offers considerable flexibility. This is because the cutout is positioned at the point where it separates from the teeth where the coil is supplied.

[0047] (7) As one embodiment of the aforementioned iron core having the aforementioned cut portion, an example can be given, The circumferential length of the cut portion along the yoke portion is greater than or equal to 1.0 mm and less than or equal to 10 mm.

[0048] If the circumferential length of the cut portion is greater than or equal to 1.0 mm, it is easy to position the iron core within the housing of the rotary motor. If the circumferential length of the cut portion is less than or equal to 10 mm, the circumferential length of the cut portion will not be too large. Therefore, the reduction in the magnetic circuit area of ​​the yoke caused by the cut portion can be suppressed. Consequently, the decrease in magnetic properties caused by the reduction in the magnetic circuit area is easily suppressed.

[0049] (8) As one embodiment of the aforementioned iron core having the aforementioned cut portion, an example can be given, The radial length of the cut portion along the yoke portion is greater than or equal to 0.5 mm and less than or equal to 5 mm.

[0050] If the radial length of the cut portion is greater than or equal to 0.5 mm, it is easy to position the iron core within the housing of the rotary motor. If the radial length of the cut portion is less than or equal to 5 mm, the radial length of the cut portion will not be too large. Therefore, it is possible to suppress the reduction in the magnetic circuit area of ​​the yoke caused by the cut portion. Consequently, it is easy to suppress the decrease in magnetic properties caused by the reduction in the magnetic circuit area.

[0051] (9) As one method of the aforementioned iron core, the following can be cited: The relative density of the pressed powder molded body is greater than or equal to 90%.

[0052] The aforementioned iron core has a high density, thus exhibiting excellent magnetic properties such as saturation magnetic flux density and mechanical properties such as strength.

[0053] (10) As one method of the aforementioned iron core, one can cite the following: The pressed powder molded body is composed of soft magnetic powder. The soft magnetic powder has multiple iron particles, which are composed of at least one metal selected from the group consisting of pure iron, Fe-Si alloys, and Fe-Al alloys.

[0054] The aforementioned iron core is high-density and has excellent dimensional accuracy. This is because the material is relatively soft, making the soft magnetic particles prone to deformation during the molding and pressing of the powder into a molded body.

[0055] (11) One aspect of the present invention relates to a stator of an axially backlash type rotary electric motor, the stator having: The iron core of any one of (1) to (10) above; and A coil, which is disposed in each of the plurality of teeth of the iron core.

[0056] The aforementioned stator enables the construction of a rotating electric motor with excellent magnetic properties and productivity. This is because the stator core is a high-density, high-productivity core as described above.

[0057] (12) One aspect of the present invention relates to a rotary electric motor having a rotor and a stator, which is an axially spaced rotary electric motor in which the rotor and the stator are arranged axially opposite each other. In this rotary motor, The stator is the stator described in (11) above.

[0058] The aforementioned rotary electric motor exhibits excellent magnetic properties and productivity. This is because the stator core is a high-density core with excellent productivity.

[0059] Detailed Description of Embodiments of the Invention

[0060] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote the same names of objects.

[0061] Implementation Method 1

[0062] [Iron core]

[0063] Main reference Figures 1 to 5 The iron core 1 according to Embodiment 1 will be described. The iron core 1 according to Embodiment 1 is used in the axial clearance type rotary motor 9 described later. Figure 12 The iron core 1 has a ring-shaped yoke 3 and multiple columnar teeth 2. Figure 1 The yoke 3 has a planar first surface 31. The first surface 31 connects the outer peripheral surface 30o and the inner peripheral surface 30i of the yoke 3. A plurality of teeth 2 are spaced apart in the circumferential direction on the first surface 31 of the yoke 3. The plurality of teeth 2 have an outer peripheral surface 21 that protrudes axially from the first surface 31 of the yoke 3. The yoke 3 and the plurality of teeth 2 are integrally formed by a pressed powder molding body. One of the features of the iron core 1 according to Embodiment 1 is that it satisfies the following conditions (1) and (2).

[0064] (1) The yoke 3 has a plurality of recesses 34. The plurality of recesses 34 are respectively connected to at least a portion of the outer peripheral surface 21 of the plurality of teeth 2.

[0065] (2) The shortest distance L1 between the outer periphery 333 of the first surface 31 and the outer periphery 21 of each of the multiple teeth 2 Figure 2 The shortest distance L2 between the entire inner periphery 334 of the first surface 31 and the outer periphery 21 of each of the plurality of teeth 2, and the total distance L2 between the inner periphery 334 of the first surface 31 and the outer periphery 21 of each of the plurality of teeth 2. Figure 2 At least one of them is a specific length.

[0066] The following is a detailed description of each structure. In the following description, the yoke 3 side of the iron core 1 is referred to as the lower side, and the tooth 2 side is referred to as the upper side.

[0067] [yoke]

[0068] The yoke 3 has an outer peripheral surface 30o, an inner peripheral surface 30i, a planar first surface 31, and a planar second surface 32. Figure 1 The first surface 31 becomes the upper surface of the yoke 3. The second surface 32 becomes the lower surface of the yoke 3. Adjacent teeth 2 of the teeth 2 arranged circumferentially in the yoke 3 are magnetically coupled to each other. The yoke 3 has a shaft hole 39 in its central part that passes through the upper and lower surfaces.

[0069] (concave)

[0070] Each recess 34 is configured to connect with at least a portion of the outer peripheral surface 21 of each tooth 2 in the circumferential direction. That is, each recess 34 connects the first surface 31 and the outer peripheral surface 21 of each tooth 2. Each recess 34 is connected by the mold 5 described later. Figure 6 The protrusion 554 of each first lower punch 55 is formed. The protrusion 554 in each first lower punch 55 is configured to connect with at least a portion of the circumferential surface of the inner peripheral surface of the second hole 552. The protrusion 554 in each first lower punch 55 suppresses breakage of the first lower punch 55. The reason is as follows: When each first lower punch 55 compresses the raw material powder of the iron core 1, the deformation of the first lower punch 55 is suppressed by the anchoring effect generated by the protrusion 554 entering the raw material powder. Therefore, the stress generated at the inner peripheral corner of the second hole 552 can be reduced. That is, the yoke 3 has a recess 34, which reduces breakage of the die 5, thus resulting in excellent productivity of the iron core 1.

[0071] Each recess 34 preferably has a portion that connects to a first region 211 of the outer peripheral surface 21 of each tooth 2 and a portion that connects to a second region 212 of the outer peripheral surface 21 of each tooth 2. Figure 2 , Figure 3The first region 211 is the region on the outer peripheral surface 21 of the tooth 2 that faces the outer peripheral surface 21 of the tooth 2 adjacent to the circumferential side of the yoke 3. The second region 212 is the region on the outer peripheral surface 21 of the tooth 2 that faces the outer peripheral surface 21 of the tooth 2 adjacent to the other circumferential side of the yoke 3. The facing regions refer to the regions opposite each other in the region between the incircle tangent to the inner peripheral sides of the plurality of teeth 2 and the circumferential circle tangent to the outer peripheral sides of the plurality of teeth 2 in a concentric circle centered on the centroid of the yoke 3.

[0072] Each recess 34 has a portion connected to the first region 211 of each tooth 2 and a portion connected to the second region 212, thereby effectively suppressing the first lower punch 55 ( Figure 6 Damage to the first lower punch 55 is prevented. In this case, the protrusion 554 of the first lower punch 55, described later, is configured to connect with the first region and the second region in the inner peripheral surface of the second hole 552. Therefore, deformation of the first lower punch 55 caused by the side pressure during compression molding is effectively suppressed. Consequently, the stress reduction effect at the inner peripheral corner of the second hole 552 is high. Each recess 34 preferably also has a portion connected along the entire length of the first region 211 of each tooth 2 and a portion connected along the entire length of the second region 212. The portion connected to the first region 211 and the portion connected to the second region 212 may be separate from each other or connected to each other. For example, it can be exemplified that when the portion connected to the first region 211 and the portion connected to the second region 212 are not connected to each other, the recess 34 has a first recess connected to the first region 211 and a second recess connected to the second region 212. In particular, each recess 34 is preferably configured to be circumferentially connected to the outer peripheral surface 21 of each tooth 2. The reason for this is that the stress reduction effect generated at the inner peripheral corner of the second hole 552 is further improved, which can further suppress the breakage of the mold 5, specifically the first lower punch 55.

[0073] In this example, each recess 34 is configured to be circumferentially connected to the outer peripheral surface 21 of each tooth 2. The planar shape of the recess 34 is an annular shape along the circumferential direction of the outer peripheral surface 21 of the tooth 2, which is a trapezoidal annular shape.

[0074] The cross-sectional shape of each recess 34 can be appropriately selected. The cross-sectional shape of each recess 34 refers to the shape of the cross section obtained by cutting each recess 34 through a surface orthogonal to the length direction, that is, the axis containing each tooth 2 and the surface orthogonal to the outer peripheral surface 21.

[0075] In this example, the cross-sectional shape of each recess 34 has an inclined surface 341 and a curved surface 342. Figures 3 to 5The inclined surface 341 is inclined in such a way that the depth D of the recess 34 increases as it approaches the outer peripheral surface 21 of each tooth 2 from the first surface 31. The depth D of the recess 34 refers to its length along the axial direction of the yoke 3. The curved surface 342 is configured as an arc connecting the inclined surface 341 to the outer peripheral surface 21 of the tooth 2. The cross-sectional shape of each recess 34 is asymmetrical with respect to the perpendicular line passing through the apex of each recess 34. The length of the inclined surface 341 is longer than the length of the curved surface 342.

[0076] Each recess 34 has an inclined surface 341 in its cross-sectional shape, which makes it easy to suppress each first lower punch 55 even when the forming pressure is increased. Figure 6 Damage to the core 1 is prevented. Therefore, high density and increased productivity are achieved. The protrusion 554 of each first lower punch 55 (described later) has an inclined surface corresponding to the inclined surface 341 of each recess 34. When the raw material powder is compressed using the first lower punch 55, pressure is applied to the inclined surface of the protrusion 554. The pressure on the inclined surface of the protrusion 554 acts towards the second hole 552 side of the first lower punch 55. That is, the pressure on the inclined surface of the protrusion 554 acts in the direction that cancels the side pressure acting on the inner circumferential surface of the second hole 552 during compression molding. Therefore, by utilizing the pressure on the inclined surface of the protrusion 554 during compression molding, at least a portion of the side pressure acting on the first lower punch 55 can be canceled. Therefore, deformation of the first lower punch 55 caused by side pressure can be suppressed. Therefore, the stress generated at the inner circumferential corner of the second hole 552 can be further reduced.

[0077] Furthermore, although the illustrations are omitted, the cross-sectional shape of each recess 34 can also be composed of inclined surfaces, vertical surfaces, and corners. The inclined surfaces are inclined in such a way that the depth D of the recess 34 increases as it approaches the outer peripheral surface 21 of each tooth 2 from the first surface 31. The vertical surfaces extend from the outer peripheral surface 21 of the tooth 2 to the bottom of the yoke 3. The corners are the intersection of the inclined surfaces and the vertical surfaces. Furthermore, the cross-sectional shape of the recess 34 can also be, for example, a semi-circular shape, a triangular shape, a rectangular shape, etc. "Semi-circular shape," "triangular shape," and "rectangular shape" do not only refer to geometric semicircles, triangles, and rectangles, but also include the range that can be substantially considered as semicircles, triangles, and rectangles. For example, "triangular shape" and "rectangular shape" include shapes with chamfered corners. Additionally, "triangular shape" includes V-shapes, and "rectangular shape" includes U-shapes.

[0078] The depth D of each recess 34 is preferably greater than or equal to 0.2 mm and less than or equal to 2.5 mm. Figure 4The width Wd of each recess 34 is preferably greater than or equal to 0.5 mm and less than or equal to 3.0 mm. The depth D of the recess 34 is as described above. The width Wd of the recess 34 refers to its length along the first surface 31 in the cross-section of the recess 34. The cross-section of the recess 34 refers to the cross-section obtained by cutting each recess 34 through a surface orthogonal to the length direction, i.e., a surface containing the axis of each tooth 2 and orthogonal to the outer peripheral surface 21. If the depth D of each recess 34 is greater than or equal to 0.2 mm or the width Wd of the recess 34 is greater than or equal to 0.5 mm, it is easy to suppress each first lower punch 55 ( Figure 6 Damage to the yoke 3 can be prevented. If the depth D of each recess 34 is less than or equal to 2.5 mm or the width Wd of each recess 34 is less than or equal to 3.0 mm, the reduction in the magnetic circuit area of ​​the yoke 3 caused by each recess 34 can be suppressed. Therefore, the decrease in magnetic properties caused by the reduction in the magnetic circuit area can be easily suppressed. The depth D of each recess 34 is further preferably greater than or equal to 0.5 mm and less than or equal to 2 mm. The width Wd of each recess 34 is further preferably greater than or equal to 1.0 mm and less than or equal to 2.0 mm. In this example, the radius of curvature R of the surface 342 is 0.5 mm, the depth D of each recess 34 is 0.5 mm, and the width Wd of each recess 34 is 1.6 mm.

[0079] (size)

[0080] The thickness Ty of the yoke 3 can be, for example, greater than or equal to 1.0 mm and less than or equal to 10 mm, and further examples are greater than or equal to 1.5 mm and less than or equal to 7.0 mm. Figure 5 The thickness Ty of the yoke 3 refers to the axial length of the yoke 3 between the first surface 31 and the second surface 32. The inner diameter of the yoke 3 is, for example, greater than or equal to 5 mm and less than or equal to 150 mm. The outer diameter of the yoke 3 is, for example, greater than or equal to 30 mm and less than or equal to 300 mm. In this example, the thickness Ty of the yoke 3 is 3.5 mm. The radial length Wy of the yoke 3, i.e., the difference between the inner and outer diameters, is 20 mm.

[0081] [Teeth]

[0082] Each tooth 2 protrudes axially from the first surface 31 of the yoke 3 relative to the yoke 3. Figures 1 to 3 , Figure 5 That is, each tooth 2 is the portion of the iron core 1 that is above the same plane of the first surface 31. The stator 8 (described later) is constructed by the iron core 1 and the coil 80. Figure 11 When ), coil 80 is set in each tooth 2.

[0083] The number of teeth 2 is multiple ( Figure 1The specific number of teeth 2 can be appropriately selected. In this example, there are 12 teeth 2. Multiple teeth 2 are integrally formed with the yoke 3. Therefore, no gaps forming magnetic gaps are created between the yoke 3 and each tooth 2. Consequently, magnetic flux flows smoothly from each tooth 2 to the yoke 3. Each tooth 2 is arranged at a predetermined interval circumferentially around the yoke 3. In this example, the intervals between adjacent teeth 2 are equidistant from each other circumferentially around the yoke 3.

[0084] Examples of the shapes of each tooth 2 include prisms and cylinders. Examples of prisms include triangular prisms (triangular or quadrangular prisms) obtained by cutting the tooth 2 through a plane orthogonal to its axis, resulting in a triangular cross-section. The axis of the tooth 2 refers to the direction of its protrusion, which is the same as the axis of the yoke 3. Examples of triangular prisms include those with an isosceles triangle cross-section. Examples of quadrangular prisms include trapezoidal prisms (trapezoidal or rectangular) cross-sections. Examples of cross-sections that are identical along the axis of the tooth 2 include cases where the cross-sections are identical. The terms "trapezoidal" and "triangular," similar to the recess 34, do not only refer to geometric trapezoids and triangles, but also include shapes with chamfered corners, as in this example, encompassing a range that can be substantially considered trapezoidal or triangular.

[0085] In this example, the shape of each tooth 2 is a trapezoidal column with a trapezoidal cross-sectional shape as described above. Figure 1 , Figure 2 Each tooth 2 has an outer peripheral surface 21 comprising a first region 211, a second region 212, an outer peripheral region 213, and an inner peripheral region 214. The first region 211 and the second region 212 are as described above. In this configuration, the first region 211 and the second region 212 intersect the circumferential direction of the yoke 3. The outer peripheral region 213 is located on the outer peripheral surface 30o side of the yoke 3, connecting the outer peripheral surface 30o side of the yoke 3 in the first region 211 and the outer peripheral surface 30o side of the yoke 3 in the second region 212. The outer peripheral region 213 is configured as an arc along the circumferential direction of the outer peripheral surface 30o of the yoke 3. The inner peripheral region 214 is located on the inner peripheral surface 30i side of the yoke 3, connecting the inner peripheral surface 30i side of the yoke 3 in the first region 211 and the inner peripheral surface 30i side of the yoke 3 in the second region 212. The inner peripheral region 214 is configured as a straight line. Regarding each tooth 2, the outer peripheral region 213 is longer, and the inner peripheral region 214 is shorter. Figure 2 The cross-sectional shape of each tooth 2 is the same along the axial direction of the tooth 2. If the shape of the tooth 2 is trapezoidal columnar, it is easy to ensure a large cross-sectional area. In addition, it is easy to reduce the dead space of the core 1 and to construct a stator 8 with a high duty cycle.

[0086] Each tooth 2 is the same size. The length of each tooth 2 is less than the length of the yoke 3. The lengths of the tooth 2 and the yoke 3 refer to the radial lengths along the yoke 3. In this example, the length of the tooth 2 is the length to which a predetermined interval can be provided between the outer periphery 333 of the first surface 31 of the yoke 3 and the outer periphery 21 of the tooth 2, and between the inner periphery 334 of the first surface 31 of the yoke 3 and the tooth 2. The cross-sectional area of ​​each tooth 2 is, for example, greater than or equal to 5 mm² and less than or equal to 800 mm². The cross-sectional area of ​​each tooth 2 refers to the area of ​​the cross section obtained by cutting the tooth 2 through a plane orthogonal to the axial direction of the tooth 2. The height Ht of each tooth 2 is, for example, greater than or equal to 3 mm and less than or equal to 40 mm. Figure 5 The height Ht of tooth 2 is the protrusion length of tooth 2 relative to the first face 31 in the axial direction of yoke 3. In this example, the height Ht of tooth 2 is 8.8 mm.

[0087] [The distance between the yoke and the teeth]

[0088] The length of at least one of the following: the shortest distance L1 between the outer periphery 333 of the first surface 31 of the yoke 3 and the outer periphery 21 of each tooth 2, and the shortest distance L2 between the inner periphery 334 of the first surface 31 of the yoke 3 and the outer periphery 21 of each tooth 2, can be set to less than or equal to 4 mm. Figure 2The shortest distance L1 between the outer periphery 333 of the first surface 31 of the yoke 3 and the outer periphery 21 of each tooth 2 sometimes simply refers to the shortest distance L1 on the outer periphery side. The shortest distance L2 between the inner periphery 334 of the first surface 31 of the yoke 3 and the outer periphery 21 of each tooth 2 sometimes simply refers to the shortest distance L2 on the inner periphery side. The aforementioned shortest distance L1 on the outer periphery side and the aforementioned shortest distance L2 on the inner periphery side refer to the distance when the yoke 3 is viewed from an axial top view. Of course, it is also possible that all of the aforementioned shortest distance L1 on the outer periphery side and all of the aforementioned shortest distance L2 on the inner periphery side satisfy the above range. When the length of at least one of the aforementioned shortest distance L1 on the outer periphery side and the aforementioned shortest distance L2 on the inner periphery side is less than or equal to 4 mm, the first lower punch 55 of the mold 5 can be effectively suppressed by having the recess 34. The length of at least one of the aforementioned shortest distance L1 on the outer periphery and the aforementioned shortest distance L2 on the inner periphery is preferably greater than or equal to 1 mm, more preferably greater than or equal to 1.5 mm and less than or equal to 3.5 mm. In this example, the total lengths of the aforementioned shortest distance L1 on the outer periphery and the aforementioned shortest distance L2 on the inner periphery are the same. Alternatively, the total lengths of the aforementioned shortest distance L1 on the outer periphery and the aforementioned shortest distance L2 on the inner periphery may also be different. In this example, the location of the aforementioned shortest distance L1 on the outer periphery is the region where the outer periphery edge 333 of the first surface 31 of the yoke 3 and the outer periphery region 213 of the outer periphery surface 21 of the tooth 2 are circumferentially opposite each other. The location of the aforementioned shortest distance L2 on the inner periphery is the portion where the circumference of each tooth 2 is bisected by a radial line segment. In this example, the total lengths of the aforementioned shortest distance L1 on the outer periphery and the aforementioned shortest distance L2 on the inner periphery are 3 mm.

[0089] [Material]

[0090] The pressed powder molded body is obtained by compressing soft magnetic powder. The pressed powder molded body is mainly composed of soft magnetic powder. The soft magnetic powder has multiple iron particles composed of pure iron or iron-based alloys. The purity of the pure iron is greater than or equal to 99% by mass. Examples of iron-based alloys include at least one selected from the group consisting of Fe-Si (silicon) alloys, Fe-Al (aluminum) alloys, Fe-Si-Al alloys, and Fe-Ni (nickel) alloys. Examples of Fe-Si alloys include silicon steel. Examples of Fe-Si-Al alloys include iron-silicon-aluminum alloys. Examples of Fe-Ni alloys include permalloy. These materials are relatively soft, therefore the soft magnetic particles are easily deformed during the pressing powder molded body formation. Therefore, the core 1 has high density and excellent dimensional accuracy. Preferably, the soft magnetic powder has an insulating coating on the surface of the iron particles. If an insulating coating is provided on the surface of the iron particles, electrical insulation between the particles is easily ensured through the insulating coating. Therefore, iron loss in the pressed powder molded body caused by eddy current losses can be reduced. Examples of insulating coatings include phosphate coatings and silica coatings.

[0091] [Relative density]

[0092] The relative density of the pressed powder molded body is preferably greater than or equal to 90%. This is because it exhibits excellent magnetic properties such as saturation magnetic flux density and mechanical properties such as strength. A relative density greater than or equal to 93% is more preferable. "Relative density of the pressed powder molded body" refers to the ratio (%) of the actual density of the pressed powder molded body to its true density. That is, the relative density of the pressed powder molded body is calculated by [(actual density of the pressed powder molded body / true density of the pressed powder molded body) × 100]. The actual density of the pressed powder molded body can be calculated by immersing it in oil, allowing the oil to permeate the pressed powder molded body, and then calculating [oil-containing density × (mass of the pressed powder molded body before oiling / mass of the pressed powder molded body after oiling)]. The oil-containing density is (mass of the pressed powder molded body after oiling / volume of the pressed powder molded body after oiling). That is, the actual density of the pressed powder molded body can be calculated by (mass of the pressed powder molded body before oiling / volume of the pressed powder molded body after oiling). The volume of the pressed powder molded body after oiling can be representatively determined by the liquid displacement method. The true density of a pressed powder molded body refers to its theoretical density when it contains no voids. The true density of a pressed powder molded body can also be determined based on the true density of the soft magnetic powder used.

[0093] [Method for manufacturing iron core (I)]

[0094] The iron core 1 according to Embodiment 1 can be manufactured by a manufacturing method (I) for an iron core having a filling process and a forming process. The filling process involves filling raw material powder into the cavity of the mold 5. Figure 6 The molding process involves compressing and molding the raw material powder within the cavity. First, refer to... Figure 6 The mold 5 will be explained, followed by an explanation of each process.

[0095] [Mold]

[0096] The mold 5 has a punch 51, an iron core rod 52, an upper punch 53, and a lower punch 54. The chamber for filling the raw material powder is composed of the punch 51, the iron core rod 52, and the lower punch 54.

[0097] (die)

[0098] The die 51 has a die hole 511. The die hole 511 has an inner peripheral surface that forms the outer peripheral surface 30° of the yoke 3. The inner peripheral shape of the die hole 511 is a shape corresponding to the shape of the outer peripheral surface 30° of the yoke 3, which is a circle in this example.

[0099] (Iron core rod)

[0100] The core rod 52 has an outer peripheral surface 521 that forms the inner peripheral surface 30i of the yoke 3. The shape of the core rod 52 corresponds to the shape of the inner peripheral surface 30i of the yoke 3, and in this example it is cylindrical. The core rod 52 is disposed inside the die hole 511 of the punch 51.

[0101] (Upward punch)

[0102] The upper punch 53 has a lower end face 531 that forms the second surface 32 of the yoke 3. The upper punch 53 is cylindrical in shape. A through hole 532 for inserting the core rod 52 is provided in the center of the upper punch 53. The inner circumference of the through hole 532 is a shape corresponding to the shape of the core rod 52, and in this example, it is circular. The lower end face 531 of the upper punch 53 is flat. The shape of the lower end face 531 of the upper punch 53 can be appropriately selected according to the shape of the second surface 32 of the yoke 3, and in this example, it is annular. The upper punch 53 is fitted between the die hole 511 of the die 51 and the core rod 52.

[0103] (Downward punch)

[0104] The lower punch 54 has a first lower punch 55 and a second lower punch 56. The lower punch 54 is fitted between the die hole 511 of the die 51 and the iron core rod 52. The first lower punch 55 and the second lower punch 56 can be driven independently in the vertical direction relative to the die 51 and the iron core rod 52, respectively.

[0105] <First Strike>

[0106] The first lower punch 55 forms the first surface 31 of the yoke 3, the concave portion 34, and the circumferential surface of the tooth portion 2. The first lower punch 55 is cylindrical in shape. The first lower punch 55 has a first hole 551, a plurality of second holes 552, and an upper end face 553.

[0107] First hole

[0108] The first hole 551 has an inner circumferential surface through which the core rod 52 is inserted. The first hole 551 is configured to pass through the center of the first lower punch 55 in the vertical direction. The inner circumferential shape of the first hole 551 corresponds to the outer circumferential shape of the core rod 52, and is circular in this example.

[0109] Second hole

[0110] The second hole 552 has an inner circumferential surface that forms the outer circumferential surface 21 of the tooth portion 2. The second hole 552 is configured to penetrate the first lower punch 55 in the vertical direction on the outer circumference of the first hole 551 of the first lower punch 55. The number of second holes 552 corresponds to the number of teeth 2, which is 12 in this example. Multiple second holes 552 are equally spaced in the circumferential direction of the first lower punch 55. The second lower punch 56 is inserted through the second hole 552.

[0111] The inner circumferential shape of the second hole 552 can be appropriately selected according to the shape of the tooth 2, and in this example, it is trapezoidal. That is, the inner circumferential surface of the second hole 552 is set into a trapezoidal ring shape through a first region, a second region, an outer circumferential region, and an inner circumferential region. The first region is the region on the inner circumferential surface of the second hole 552 that is opposite to the inner circumferential surface of the second hole 552 adjacent to the circumferential side of the first lower punch 55. The second region is the region on the inner circumferential surface of the second hole 552 that is opposite to the inner circumferential surface of the second hole 552 adjacent to the other circumferential side of the first lower punch 55. The opposite region refers to the region between the incircle tangent to the inner circumferential sides of the plurality of second holes 552 and the circumferential circle tangent to the outer circumferential sides of the plurality of second holes 552 in a concentric circle with the centroid of the first lower punch 55 as the center. The first region and the second region intersect the upper end face 553 circumferentially. The outer peripheral region is located on the outer peripheral surface of the first lower punch 55, connecting the ends of the first lower punch 55 in the first region and the second region to each other. The outer peripheral region is configured as an arc along the circumferential direction of the outer peripheral surface of the first lower punch 55. The inner peripheral region is located on the inner peripheral surface of the first lower punch 55, connecting the ends of the first lower punch 55 in the first region and the second region to each other. The inner peripheral region is configured as a straight line.

[0112] Top surface

[0113] The upper end face 553 forms the first surface 31 of the yoke 3 and the recess 34. The upper end face 553 is annular in shape. The shortest distance between the outer periphery of the upper end face 553 and the inner periphery of the second hole 552 corresponds to the aforementioned shortest distance L1 on the outer periphery side, and the shortest distance between the inner periphery of the upper end face 553 and the inner periphery of the second hole 552 corresponds to the aforementioned shortest distance L2 on the inner periphery side. The shortest distance between the outer periphery of the upper end face 553 and the inner periphery of the second hole 552, and the shortest distance between the inner periphery of the upper end face 553 and the inner periphery of the second hole 552 are greater than or equal to 1 mm and less than or equal to 4 mm. The above two shortest distances are... Figure 6 The length of the paper in the left-right direction. In this example, the two shortest distances mentioned above are 3mm.

[0114] The upper end face 553 has a protrusion 554 that connects to the inner peripheral surface of the second hole 552. The protrusion 554 forms the recess 34 of the yoke 3. That is, by appropriately adjusting the forming area, cross-sectional shape, and size of the protrusion 554, the forming area, cross-sectional shape, and size of the recess 34 of the yoke 3 are adjusted. In this example, the protrusion 554 is configured to connect around the entire circumference of the inner peripheral surface of the second hole 552.

[0115] <Second Strike>

[0116] The second lower punch 56 has an upper end face 561 forming the upper surface of the tooth 2. The shape of the second lower punch 56 corresponds to the inner circumferential shape of the second hole 552, and in this example, it is a trapezoidal column. The upper end face 561 of the second lower punch 56 is composed of a plane. The shape of the upper end face 561 can be appropriately selected according to the end face shape of the tooth 2, and in this example, it is a trapezoidal shape. The number of second lower punches 56 is the same as the number of second holes 552, and in this example, it is 12.

[0117] [Filling process]

[0118] In this process, raw material powder is filled into the cavity formed by the die 51, the core rod 52, and the lower punch 54. The aforementioned soft magnetic powder can be used as the raw material powder. The raw material powder may also contain a binder and a lubricant in addition to the soft magnetic powder. A lubricant may also be applied to the die 5. For example, the average particle size of the soft magnetic material powder used as the raw material powder is greater than or equal to 20 μm and less than or equal to 350 μm. If the average particle size of the powder is within the above range, the powder is easy to process and easy to compress and mold. The average particle size of the powder may be greater than or equal to 40 μm and less than or equal to 300 μm, and further less than or equal to 250 μm. The average particle size of the powder is set using laser diffraction. Scattering particle size The particle size distribution is measured using a particle size distribution measuring device, and the cumulative mass of the particle size reaches 50% of the total mass of all particles.

[0119] [Molding process]

[0120] In this process, the raw material powder in the chamber is compressed and formed by the upper punch 53 and the lower punch 54. The higher the pressure during compression forming, the easier it is to densify, and the higher the relative density of the iron core 1 can be manufactured. Examples of such pressures include 700 MPa or greater, and more specifically, 980 MPa or greater.

[0121] [Other processes]

[0122] After the molding process, heat treatment can be performed as needed. For example, heat treatment can remove strain, thereby producing a low-loss core 1. Alternatively, heat treatment can also remove binders and lubricants. When the raw material powder contains the aforementioned coated particles, the heat treatment temperature is preferably less than or equal to the decomposition temperature of the insulating coating.

[0123] [Effects]

[0124] Regarding the core 1 according to Embodiment 1, the size of the tooth portion 2 is proportionally larger than the size of the yoke portion 3. Based on this, even if the forming pressure is increased, damage to the first lower punch 55 can be suppressed, thus the core 1 has high density and excellent productivity.

[0125] Implementation Method 2

[0126] [Iron core]

[0127] Reference Figure 7 , Figure 8 The iron core 1 according to Embodiment 2 will be described. The iron core 1 according to Embodiment 2 differs from the iron core 1 according to Embodiment 1 in that it has a cutout 35 in the yoke 3. The following description focuses on the differences from Embodiment 1. Descriptions of structures identical to those in Embodiment 1 are omitted.

[0128] [yoke]

[0129] (Incision area)

[0130] The cutout 35 is a recess, which is used relative to the rotary motor 9 described later. Figure 12 The housing 92 positions the core 1 or engages the end of the winding of the coil 80 constituting the stator 8 (described later). A cutout 35 is provided on at least one of the outer peripheral surface 30o side and the inner peripheral surface 30i side of the yoke 3, compared to each tooth 2. The cutout 35 opens on at least one of the outer peripheral surface 30o and the inner peripheral surface of the yoke 3. The cutout 35 is formed by cutting away the entire area of ​​the yoke 3 in the thickness direction.

[0131] The cut portion 35 is preferably formed at least one of the outer peripheral surface 30o and the inner peripheral surface 30i of the yoke portion 3, corresponding to the portion between adjacent teeth 2. In this example, the cut portion 35 is provided at each portion corresponding to the portion between adjacent teeth 2. Figure 8 That is, the number of incisions 35 in this example is 12 (). Figure 7 In the case of having multiple cutouts 35 as in this example, at least one cutout 35 can be used for positioning the core 1, and the other cutouts 35 can be used for attaching the ends of the winding.

[0132] The planar shape of the cut portion 35, viewed from the tooth portion 2 side, is trapezoidal in this example. Figure 8 Furthermore, the planar shape of the cutout portion 35 can also be triangular, rectangular, semi-circular, etc. The terms "trapezoidal," "triangular," "rectangular," and "semi-circular" here, like the recess 34, are not limited to geometric trapezoids, triangles, rectangles, and semi-circles, but also include shapes with chamfered corners as in this example, encompassing a range that can be substantially considered trapezoidal, triangular, rectangular, and semi-circular.

[0133] The circumferential length of the cut portion 35 along the yoke 3 and the radial length of the cut portion 35 along the yoke 3 can be appropriately selected according to the forming location and shape of the cut portion 35. The circumferential length along the yoke 3 is sometimes simply referred to as the circumferential length, and the radial length along the yoke 3 is sometimes simply referred to as the radial length. The aforementioned circumferential length of the cut portion 35 refers to the circumferential length of the open end of the cut portion 35. That is, the aforementioned circumferential length of the cut portion 35 refers to the length of the cut portion 35 along the extension line of the outer periphery 333 of the first surface 31. The aforementioned radial length of the cut portion 35 refers to the maximum depth of the cut portion 35. That is, the aforementioned radial length of the cut portion 35 refers to the maximum length of the cut portion 35 radially from the extension line of the outer periphery 333 of the first surface 31 towards the yoke 3. The aforementioned circumferential length of the cut portion 35 is preferably less than the minimum interval between the first region 211 and the second region 212 of the adjacent tooth portion 2.

[0134] In this example, the circumferential length of the cut portion 35 is, for example, greater than or equal to 1.0 mm and less than or equal to 10 mm. The radial length of the cut portion 35 is, for example, greater than or equal to 0.5 mm and less than or equal to 5 mm. If the circumferential length of the cut portion 35 is greater than or equal to 1.0 mm, or the radial length of the cut portion 35 is greater than or equal to 0.5 mm, it is easy to position the core 1, etc. If the circumferential length of the cut portion 35 is less than or equal to 10 mm, or the radial length of the cut portion 35 is less than or equal to 5 mm, the cut portion 35 will not be too large. Therefore, the reduction in the magnetic circuit area of ​​the yoke portion 3 caused by the cut portion 35 can be suppressed. Thus, it is easy to suppress the decrease in magnetic properties caused by the reduction in the magnetic circuit area. The circumferential length of the cut portion 35 is further preferably greater than or equal to 1.5 mm and less than or equal to 8 mm. The radial length of the cut portion 35 is further preferably greater than or equal to 1.0 mm and less than or equal to 4 mm. In this example, the circumferential length of the cut portion 35 is approximately 6 mm. The radial length of the cut portion 35 is 2.5 mm.

[0135] [The distance between the yoke and the teeth]

[0136] The shortest distance L1 between the outer periphery 333 of the first surface 31 of the yoke 3 and the outer periphery 21 of each tooth 2, that is, the shortest distance L1 on the outer periphery side, is located between the corner of the cut 35 and the corner of the outer periphery 21 of each tooth 2. Figure 8 The corners of the outer peripheral surfaces 21 of each tooth 2 are the connection points between the outer peripheral region 213 and the first region 211, and between the outer peripheral region 213 and the second region 212. The length of the shortest distance L1 on the outer peripheral side is approximately 2.7 mm. Furthermore, the length between the outer peripheral edge 333 of the first surface 31 of the yoke 3, which bisects the circumference of the tooth 2 with a radially bisecting line segment, and the outer peripheral surface 21 of each tooth 2 is the same as that of the core 1 in Embodiment 1, which is 3 mm. The position and length of the shortest distance L2 on the inner peripheral side between the inner peripheral edge 334 of the first surface 31 of the yoke 3 and the outer peripheral surface 21 of each tooth 2, i.e., the shortest distance L2 on the inner peripheral side, are the same as those on the inner peripheral side of the core 1 in Embodiment 1. That is, the position of the shortest distance L2 on the inner peripheral side is the point where the circumference of the tooth 2 is bisected with a radially bisecting line segment. The length of the shortest distance L2 on the inner peripheral side is 3 mm.

[0137] [Method for manufacturing iron core (II)]

[0138] The iron core 1 according to Embodiment 2 can be manufactured by an iron core manufacturing method (II) having the same process as the iron core manufacturing method (I) described above. In the iron core manufacturing method (II), the mold 5 used is the same as the mold 5 used in the iron core manufacturing method (I). Figure 6The die 51, upper punch 53, and first lower punch 55 of the mold 5 in method (II) of manufacturing the iron core are different from those in method (I). (See reference...) Figure 9 , Figure 10 The mold 5 used in the iron core manufacturing method (II) will be described below. The following description focuses on the differences between the mold 5 used in the iron core manufacturing method (I). Figure 9 This shows the state of the chamber before it is filled with raw material powder, as viewed from the upper punch side. Figure 9 For ease of explanation, the punching die 51 and the iron core rod 52 are marked with shaded lines.

[0139] [Mold]

[0140] (die)

[0141] The inner peripheral surface of the die 51 has a protrusion 512 that protrudes radially toward the inner peripheral side of the die 51. Figure 9 The protrusions 512 form the cutouts 35 of the yoke 3. The number, shape, size, and location of each protrusion 512 can be appropriately selected based on the number, shape, size, and location of the cutouts 35. In this example, there are 12 protrusions 512. In this example, the shape of the protrusions 512 is trapezoidal. The locations of the protrusions 512 on the outer peripheral surface of the first lower punch 55 correspond to the locations between adjacent second holes 552.

[0142] (Upward punch)

[0143] The outer peripheral surface of the upper punch 53 is omitted from the illustration, but it has recesses for the protrusions 512 of the die 51 to engage with. The number, shape, size, and location of the recesses correspond to the protrusions 512.

[0144] (Downward punch)

[0145] <First Strike>

[0146] The outer peripheral surface of the first lower punch 55, like the upper punch 53, has a recess 555 for the protrusion 512 of the die 51 to engage with. Figure 9 , Figure 10 The number, shape, size, and location of the recesses 555 correspond to those of the protrusions 512.

[0147] [Effects]

[0148] Similar to the core 1 of Embodiment 1, the core 1 of Embodiment 2 is high-density and has a large ratio of tooth 2 size to yoke 3 size, resulting in excellent productivity. Furthermore, the yoke 3 has a cutout 35, which allows for the positioning of the core 1 within the housing 92 of the rotary motor 9 (described later), thus facilitating the construction of the rotary motor 9.

[0149] Implementation Method 3

[0150] 〔stator〕

[0151] Reference Figure 11 The stator 8 according to Embodiment 3 will be described below. The stator 8 according to Embodiment 3 has an iron core 1 and a coil 80. The iron core 1 can be the iron core 1 according to Embodiment 1 or the iron core 1 according to Embodiment 2. The coil 80 is disposed on each of the plurality of teeth 2 of the iron core 1. This stator 8 is used in an axially backlash type rotary motor 9. Figure 11 In the example, stator 8 has Figure 7 , Figure 8 The illustrated embodiment 2 pertains to the case of the iron core 1. Of course, the stator 8 can also have... Figures 1 to 5 The iron core 1 shown.

[0152] Each coil 80 has a cylindrical portion obtained by winding the wire into a spiral shape. In this example, the coil 80 is a flat, upright wound coil with the wire configured as a trapezoidal cylindrical shape covering a flat wire. Furthermore, in Figure 11 In the diagram, only the cylindrical portion is shown in a simplified manner; the two ends of the winding are omitted from the illustration. The two ends of the winding can be hooked onto the cutout 35 of the yoke 3 of the iron core 1 and led out. The stator 8 can be manufactured by separately fabricating a coil 80 and inserting the coil 80 into the outside of the tooth 2.

[0153] [Effects]

[0154] The stator 8 of Embodiment 3 has a high-density and highly productive core 1 as in Embodiment 2, thus enabling the construction of an axially gap type rotary motor 9 with excellent magnetic properties and productivity.

[0155] Implementation Method 4

[0156] [Rotating Electric Machine]

[0157] Reference Figure 12 The rotary motor 9 according to Embodiment 4 will be described. Figure 12 This is a cross-sectional view obtained by cutting through a plane parallel to the plane of the rotating shaft 91 of the rotary motor 9 and passing through the cutout 35 of the iron core 1. The rotary motor 9 has a rotor 90 and a stator 8. The stator 8 described in Embodiment 3 can be used as the stator 8. This rotary motor 9 is an axially spaced type rotary motor in which the rotor 90 and stator 8 are axially opposed. The rotary motor 9 can be used as an electric motor or a generator. Figure 12 Examples of single-rotor and double-stator structures are shown, where one rotor 90 is assembled with two stators 8 sandwiched between them. Other examples include structures with one rotor and one stator, and structures where one stator is assembled with two rotors sandwiched between them. The rotary electric machine 9 has a housing 92.

[0158] The housing 92 has a cylindrical internal space for accommodating the stator 8 and the rotor 90. The housing 92 has a cylindrical portion 921 and two plates 923.

[0159] A cylindrical portion 921 surrounds the outer periphery of the stator 8 and the rotor 90. Plates 923 are respectively disposed on both sides of the cylindrical portion 921. Preferably, the cylindrical portion 921 has a positioning portion for positioning the stator 8. This positioning portion is composed of a protrusion 922 protruding from the inner surface of the cylindrical portion 921, which engages with the cutout 35 of the yoke 3 of the core 1. This engagement positions the stator 8 relative to the housing 92.

[0160] Two plates 923 are fixed to the end faces of the cylindrical portion 921 by clamping the stator 8 and rotor 90 from both axial sides. Each plate 923 has a through hole at its center. A bearing 93 is installed in the through hole, through which the rotating shaft 91 is inserted. Additionally, a bearing is also installed in the shaft hole 39 of the yoke 3, through which the rotating shaft 91 is inserted. The bearing in the shaft hole 39 is not shown in the diagram. The rotating shaft 91 passes through the housing 92.

[0161] The rotor 90 has a rotor body and a plurality of magnets 95. The rotor 90 is a flat plate. Each magnet 95 is, for example, a flat plate with a planar shape corresponding to the planar shape of the end face of the tooth 2. The rotor body supports the plurality of magnets 95. The rotor body is an annular component and is rotatable by means of a rotation shaft 91. The magnets 95 are arranged at equal intervals in the circumference of the rotor body. The magnets 95 are magnetized in the axial direction of the rotation shaft 91. The magnetization directions of adjacent magnets 95 in the circumference of the rotor body are opposite to each other. If the rotor body rotates, the magnets 95 also rotate with the rotor body.

[0162] The stator 8 is configured such that the end face of the tooth section 2 is opposite to the magnet 95 of the rotor 90. When the rotor 90 rotates, the end face of the tooth section 2 receives magnetic flux from the rotating magnet 95.

[0163] [Effects]

[0164] The rotary motor 9 of Embodiment 4 has the stator 8 of Embodiment 3, thus exhibiting excellent magnetic properties and productivity.

[0165] Experimental Example 1

[0166] according to Figure 9 , Figure 10 (For reference only) Figure 6 The presence or absence of the protrusion 554 of the first lower punch 55 shown in the figure evaluated the difference in the maximum stress value (MPa) generated in the first lower punch 55 during compression molding.

[0167] [Sample No. 1]

[0168] In sample No.1, a reference was used. Figure 9 , Figure 10 The mold 5 described herein was manufactured as a reference. Figure 7 , Figure 8 The iron core 1 involved in the described embodiment 2. That is, the first lower punch 55 has a protrusion 554 and a recess 555 ( Figure 9 , Figure 10 The protrusion 554 is configured to be connected around the entire circumference of the inner peripheral surface of the second hole 552. The protrusion 554 is trapezoidal annular in shape. The recess 555 is provided on the outer peripheral surface of the first lower punch 55. The recess 555 is trapezoidal in shape.

[0169] The shortest distance between the outer periphery of the upper end face 553 of the first lower punch 55 and the inner periphery of the second hole 552 is located between the corner of the recess 555 and the corner of the inner periphery of the second hole 552. The corner of the inner periphery of the second hole 552 is the connection point between the first region and the outer periphery region of the second hole 552, and also the connection point between the second region and the outer periphery region. The shortest distance between the inner periphery of the upper end face 553 of the first lower punch 55 and the inner periphery of the second hole 552 is located at the point where the circumference of the second hole 552 is bisected by a radial line segment. The length of the shortest distance between the outer periphery of the upper end face 553 of the first lower punch 55 and the inner periphery of the second hole 552 is set to approximately 2.7 mm. The length of the shortest distance between the inner periphery of the upper end face 553 of the first lower punch 55 and the inner periphery of the second hole 552 is set to 3 mm.

[0170] The core 1 of the manufactured sample No.1 is integrally formed from a circular ring-shaped yoke 3 and multiple teeth 2. Figure 7 , Figure 8 The yoke 3 has multiple recesses 34 and multiple cutouts 35. Each recess 34 is configured to connect circumferentially to the outer peripheral surface 21 of each tooth 2. Each cutout 35 is provided in the outer peripheral surface 30° of the yoke 3 at a location corresponding to adjacent teeth 2. The shortest distance L1 between the outer peripheral edge 333 of the first surface 31 of the yoke 3 and the outer peripheral surface 21 of the tooth 2 is located between the corner of the cutout 35 and the corner of the outer peripheral surface 21 of the tooth 2. The corner of the outer peripheral surface 21 of the tooth 2 is the connection point between the outer peripheral region 213 and the first region 211, and the connection point between the outer peripheral region 213 and the second region 212. The shortest distance L2 between the inner peripheral edge 334 of the first surface 31 of the yoke 3 and the outer peripheral surface 21 of the tooth 2 is located at the point where the circumference of each tooth 2 is bisected by a radial line segment. The length of the shortest distance L1 on the outer peripheral side is approximately 2.7 mm. The shortest distance L2 on the inner circumference side is 3 mm.

[0171] [Sample No. 101]

[0172] In sample No. 101, a core identical to that of sample No. 1 was manufactured, except that the yoke lacks a recess connecting to the outer circumferential surface of each tooth. The first lower punch 55 of the die 5 used in manufacturing the core of sample No. 101 is as follows... Figure 13 As shown, there is no protrusion connecting to the inner circumferential surface of the second hole 552, and the upper end surface 553 is flat.

[0173] The core of sample No. 101 is identical to the core of sample No. 1, except that it does not have a recess in the yoke that connects to the outer peripheral surface of each tooth. That is, the position and length of the shortest distance L1 on the outer peripheral side and the position and length of the shortest distance L2 on the inner peripheral side of the core of sample No. 101 are the same as those of the core of sample No. 1.

[0174] [Stress Analysis]

[0175] During the manufacturing of core 1 of sample No.1 and core 101, the stress distribution acting on the first lower punch 55 was analyzed using CAE (Computer Aided Engineering). Based on the CAE analysis results, the maximum stress value (MPa) generated by the first lower punch 55 was calculated.

[0176] For sample No.1, the first lower punch 55, as Figure 10 As shown by the double-dotted circle, the maximum stress acts on a small area near the corner of the outer peripheral surface of the first lower punch 55 on the inner circumferential surface of the second hole 552. This maximum stress value is approximately 936 MPa.

[0177] On the other hand, for the first lower punch 55 of sample No.101, such as Figure 13 As shown by the double-dotted circle, the maximum stress in the inner circumferential surface of the second hole 552 occurs in a large region near the corner of the outer circumferential surface of the first lower punch 55. This maximum stress value is approximately 1205 MPa.

[0178] It can be seen that the maximum stress of the first lower punch 55 of sample No. 1 is reduced by more than 20% compared with that of the first lower punch 55 of sample No. 101. That is, even if the forming pressure is increased, the first lower punch 55 of sample No. 1 is less prone to deformation and breakage compared with sample No. 101. Therefore, the first lower punch 55 of sample No. 1 can manufacture a high-density iron core 1 with a large ratio of tooth 2 to yoke 3 with high productivity.

[0179] This invention is not limited to the above examples, but is shown in the claims and includes all modifications within the scope of the claims.

[0180] Explanation of the label

[0181] 1 Iron core

[0182] 2. Teeth

[0183] 21 Outer Peripheral Surface

[0184] 211 First District

[0185] 212 Second Area

[0186] 213 Peripheral area

[0187] 214 Inner peripheral area

[0188] 3 yoke

[0189] 30° outer perimeter

[0190] 30i inner circumferential surface

[0191] 31 First page

[0192] 32 Second page

[0193] 333 peripheral edge

[0194] 334 inner periphery

[0195] 34 recess

[0196] 341 Inclined Surface

[0197] 342 Surface

[0198] 35. Incision site

[0199] 39 Shaft Hole

[0200] 5. Mold

[0201] 51 Stamping Die

[0202] 511 Die Hole

[0203] 512 convex part

[0204] 52 Iron core rod

[0205] 521 Outer Peripheral Surface

[0206] 53 Upper punch

[0207] 531 Lower end face

[0208] 532 Through Hole

[0209] 54 Downward punch

[0210] 55 First punch

[0211] 551 First Hole

[0212] 552 Second Hole

[0213] 553 Top surface

[0214] 554 convex part

[0215] 555 recess

[0216] 56 Second punch

[0217] 561 Top surface

[0218] 8 Stator

[0219] 80 coil

[0220] 9 Rotary motors

[0221] 90 rotor

[0222] 91 Rotation axis

[0223] 92. Shell

[0224] 921 Cylindrical section

[0225] 922 convex part

[0226] 923 board

[0227] 93 bearing

[0228] 95 magnets

[0229] L1, L2 shortest distance

[0230] D Depth

[0231] Wd width

[0232] R (radius of curvature)

[0233] Ty thickness

[0234] Wy length

[0235] Ht height

Claims

1. A core for use in an axially spaced rotary electric motor. The iron core has the following characteristics: A ring-shaped yoke; and Multiple columnar teeth are arranged circumferentially spaced apart from each other on the yoke. The yoke has: outer peripheral surface; Inner circumference; A planar first surface that connects the outer peripheral surface and the inner peripheral surface; Multiple recesses, which are connected to the first surface; and The slit portion, which is located on at least one of the outer and inner circumferential surfaces of the yoke portion, beyond the teeth, opens at a location corresponding to the interval between adjacent teeth. Each of the plurality of teeth has an outer peripheral surface that protrudes axially from the first surface in the yoke. The plurality of recessed portions are respectively circumferentially connected to the outer peripheral surface of the plurality of teeth. The shortest distance between at least one of the outer peripheral edge and the inner peripheral edge of the first surface and the respective outer peripheral surface of the plurality of teeth is all less than or equal to 4 mm. The yoke and the plurality of teeth are formed by an integrally molded powder body.

2. The iron core according to claim 1, wherein, Each of the plurality of recesses has an inclined surface that deepens as it approaches the outer peripheral surface of each of the plurality of teeth from the first surface.

3. The iron core according to claim 1 or 2, wherein, The circumferential length of the cut portion along the yoke portion is greater than or equal to 1.0 mm and less than or equal to 10 mm.

4. The iron core according to claim 1 or 2, wherein, The radial length of the cut portion along the yoke portion is greater than or equal to 0.5 mm and less than or equal to 5 mm.

5. The iron core according to claim 1 or 2, wherein, The relative density of the pressed powder molded body is greater than or equal to 90%.

6. The iron core according to claim 1 or 2, wherein, The pressed powder molded body is composed of soft magnetic powder. The soft magnetic powder has multiple iron particles, which are composed of at least one metal selected from the group consisting of pure iron, Fe-Si alloys, and Fe-Al alloys.

7. A stator, which is an axial clearance type stator for a rotary electric machine. The stator has the following characteristics: The iron core according to any one of claims 1 to 6; and A coil, which is disposed in each of the plurality of teeth of the iron core.

8. A rotary electric motor having a rotor and a stator, wherein the rotor and the stator are arranged axially opposite each other in an axially spaced manner, is an axially spaced rotary electric motor. In this rotary motor, The stator is the stator according to claim 7.

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