Iron core, stator and rotating motor

Abstract

A core used in an axial gap type rotating electric machine, the core comprising: an annular yoke having a plurality of through holes arranged in a circumferential direction; and a plurality of columnar teeth arranged in the circumferential direction of the yoke, with one end of each tooth being inserted into the plurality of through holes, the yoke and the teeth being composed of independent pressed powder molded bodies, with one end of each tooth being arranged in a direction biased to one side in the through hole.

Description

Technical Field

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

[0002] This application claims priority based on Japanese Patent Application No. 2018-246317 filed on December 27, 2018, and cites all the contents described in the above-mentioned Japanese application. Background Art

[0003] Patent document 1 discloses an axial gap type electric motor in which a rotor and a stator are arranged opposite to each other in the axial direction of the rotor as one of the rotating electric machines. The stator used in this rotating electric machine has: an iron core having a yoke and a plurality of teeth; and a coil arranged on each tooth. As a representative case, the yoke is a circular ring plate-shaped component. Each tooth is a columnar component protruding in the axial direction of the yoke, and is separated and arranged in the circumferential direction of the yoke. Patent document 1 also discloses a case in which the yoke and the teeth are separably constructed.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2009-044829 Summary of the invention

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

[0006] The core has:

[0007] an annular yoke having a plurality of through holes arranged in a circumferential direction; and

[0008] a plurality of columnar teeth, which are arranged in the circumferential direction of the yoke, and one end of each of which is inserted into the plurality of through holes,

[0009] The yoke and the teeth are formed of independent powder compacts.

[0010] The one end of each tooth portion is disposed in a biased manner in the through hole.

[0011] The stator of the present invention has:

[0012] The iron core of the present invention: and

[0013] A coil is arranged on each of the teeth.

[0014] The rotating electrical machine of the present invention includes the stator of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic perspective view showing an example of the iron core according to the embodiment.

[0016] Figure 2It is a diagram for explaining the distance between the outer peripheral surface of one end portion of the tooth portion and the inner peripheral surface of the through hole of the yoke portion in the iron core according to the embodiment.

[0017] Figure 3 This is an example in which the teeth of the core according to the embodiment are provided to face the proximity region, and a schematic plan view of a portion of the core is shown.

[0018] Figure 4 This is an example in which the teeth of the core according to the embodiment have the proximity region on the same side in the circumferential direction of the yoke, and shows a schematic plan view of a part of the core.

[0019] Figure 5 is along Figure 1 A partial schematic cross-sectional view of the iron core of the (V)-(V) line.

[0020] Figure 6 It is a schematic perspective view showing an example of a stator according to the embodiment.

[0021] Figure 7 A schematic cross-sectional view showing an example of a rotating electrical machine according to an embodiment DETAILED DESCRIPTION

[0022] [Problems to be Solved by the Invention]

[0023] It is desired to construct an axial gap type rotating electrical machine that can easily assemble a stator and obtain a high torque.

[0024] Therefore, one of the objects of the present invention is to provide an iron core that can construct a rotating electrical machine having a high torque and has excellent manufacturability of a stator.

[0025] Another object of the present invention is to provide a stator that can construct a rotating electrical machine having a high torque and has excellent manufacturability.

[0026] Furthermore, another object of the present invention is to provide a rotating electrical machine having high torque and excellent manufacturability.

[0027] [Effects of the Invention]

[0028] The iron core of the present invention can construct a rotating electrical machine having a high torque, and the manufacturability of the stator is also excellent.

[0029] The stator of the present invention can construct a rotating electrical machine having a high torque, and is also excellent in manufacturability.

[0030] The rotating electrical machine of the present invention has high torque and is excellent in manufacturability.

[0031] [Description of Embodiments of the Invention]

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

[0033] (1) An iron core according to one embodiment of the present invention is used in an axial gap type rotating electrical machine.

[0034] The core has:

[0035] an annular yoke having a plurality of through holes arranged in a circumferential direction; and

[0036] a plurality of columnar teeth, which are arranged in the circumferential direction of the yoke, and one end of each of which is inserted into the plurality of through holes,

[0037] The yoke and the teeth are formed of independent powder compacts.

[0038] The one end of each tooth portion is disposed in a biased manner in the through hole.

[0039] The yoke and the tooth of the iron core of the present invention are composed of independent powder compacts. Therefore, the iron core of the present invention is excellent in the manufacturability of the stator. The tooth before being fixed to the yoke is a columnar body with a simple shape. On the other hand, the shape of the powder compact in which the yoke and the tooth are an integral part is complex. Therefore, it is easier to install the coil on the tooth before fixing the yoke than to install the coil on the tooth of the powder compact in which the yoke and the tooth are an integral part. In addition, it is easier to mold the powder compact in the case of molding the powder compacts of simple shapes of the yoke and the tooth than to mold the powder compact of complex shape.

[0040] In the core of the present invention, regarding the fixing of the tooth portion relative to the yoke portion, one end portion of the tooth portion is arranged to one side in a through hole formed in the yoke portion. Therefore, the core of the present invention can suppress the reduction of torque and can construct an axial gap type rotating electric machine with high torque. Arrangement to one side in the through hole refers to a region where the interval between the outer peripheral surface of one end portion of the tooth portion and the inner peripheral surface of the through hole is locally small. Arrangement to one side in the through hole refers to, quantitatively, having a region that satisfies less than or equal to 50% of the average value of the interval between the outer peripheral surface of one end portion of the tooth portion and the inner peripheral surface of the through hole. Arrangement to one side in the through hole refers to, qualitatively, when the outer shape of the tooth portion and the hole shape of the through hole are similar, the center of gravity of the tooth portion and the center of gravity of the through hole are inconsistent. By arranging the tooth portion to one side in the through hole, a region with a small gap between the tooth portion and the yoke portion, which becomes a magnetic gap, can be formed. As a result, the magnetic flux passes well between the tooth portion and the yoke portion through the region with a small gap.

[0041] (2) As an example of the iron core of the present invention,

[0042] In one embodiment, the tooth portion has a proximity region in which a distance between an outer peripheral surface of the one end and an inner peripheral surface of the through hole is less than or equal to 0.05 mm.

[0043] In the above-mentioned method, the interval between the proximity area of ​​the tooth portion and the inner peripheral surface of the through hole is very small. Therefore, in the above-mentioned method, the proximity area of ​​the tooth portion can be regarded as an area substantially connected to the inner peripheral surface of the through hole. Therefore, it can be said that the gap that can be generated between the proximity area of ​​the tooth portion and the yoke portion is not easy to become a magnetic gap. Therefore, in the above-mentioned method, the passage of the magnetic flux between the tooth portion and the yoke portion can be ensured to be better through the proximity area of ​​the tooth portion. Therefore, the above-mentioned method makes it easier to suppress the reduction of torque and can construct an axial gap type rotating motor with high torque.

[0044] (3) As an example of the iron core of (2) above,

[0045] In one embodiment, a ratio of a length of the proximity region along a circumferential direction of the through hole to a circumferential length of the through hole is greater than or equal to 20%.

[0046] The above method has a long tooth proximity region, so the magnetic flux between the tooth and the yoke can be better ensured through the tooth proximity region. Therefore, the above method can more easily suppress the reduction of torque and build an axial gap type rotating electric machine with higher torque.

[0047] (4) As an example of the core of (2) or (3) above,

[0048] In one embodiment, the difference between the maximum value and the minimum value of the interval between the outer peripheral surface of the one end and the inner peripheral surface of the through hole is less than 0.40 mm.

[0049] The above method can be said to have no region where the above interval is locally large, that is, a region that becomes a large magnetic gap. Therefore, the above method can easily ensure that the magnetic flux between the tooth portion and the yoke portion passes well. Therefore, the above method can easily suppress the reduction of torque and can construct an axial gap type rotating electric machine with high torque.

[0050] (5) As an example of the core of any one of (2) to (4) above,

[0051] In one embodiment, the tooth portion includes at least a part of the proximity region on an outer peripheral side of the yoke portion in the tooth portion.

[0052] As a representative case, the outer shape of the tooth portion is a trapezoid. In the tooth portion of the above shape, the length of the area located on the outer peripheral side of the yoke portion (hereinafter, sometimes referred to as the outer peripheral area) is longer than the length of the area located on the inner peripheral side (hereinafter, sometimes referred to as the inner peripheral area). Therefore, if the outer peripheral area of ​​the tooth portion includes an approach area, it is easy to ensure that the approach area is long. The approach area is long, so that the above method can easily ensure good passage of magnetic flux between the tooth portion and the yoke portion via the approach area of ​​the tooth portion. Therefore, the above method makes it easier to suppress the reduction of torque and can construct an axial gap type rotating motor with higher torque.

[0053] (6) As an example of any one of the cores in (2) to (5) above,

[0054] In one embodiment, the tooth portions adjacent to each other in the circumferential direction of the yoke have at least a part of the proximity region on the opposite side of the adjacent tooth portions.

[0055] In the above method, the adjacent tooth portions are arranged in close proximity to each other. Therefore, it is easy to ensure that the magnetic flux passes well between the adjacent tooth portions through the close proximity of each tooth portion. Therefore, the above method can easily suppress the reduction of torque and can construct an axial gap type rotating motor with high torque. When the above method is used in a multi-phase AC rotating motor, any of the same-phase coils and out-of-phase coils can be arranged on each tooth portion.

[0056] (7) As an example of the iron core of (6) above,

[0057] An example is a mode in which coils of the same phase are arranged on the adjacent teeth.

[0058] The above-described method can more easily suppress a decrease in torque than when the coils are arranged in different phases.

[0059] (8) As an example of the core of any one of (2) to (5) above,

[0060] In one embodiment, the tooth portion includes at least a part of the approach region on the same side of the yoke portion in the circumferential direction of the tooth portion.

[0061] The above method can easily ensure good passage of magnetic flux through the proximity area of ​​each tooth portion. Therefore, the above method can easily suppress the reduction of torque and can construct an axial gap type rotating electric machine with high torque. In addition, the above method can set the fixing state of each tooth portion relative to the yoke portion to be the same, so it is also excellent in the manufacturability of the iron core.

[0062] (9) As an example of the iron core of the present invention,

[0063] In one embodiment, the tooth portion has one end surface located inside the through hole and another end surface located outside the through hole.

[0064] The yoke has a first surface located on the protruding side of the tooth portion and a second surface opposite to the first surface.

[0065] When a surface obtained by extending the second surface is defined as a reference surface and a length from the reference surface to the other end surface is defined as a height of the tooth portion,

[0066] A fluctuation in height of the plurality of teeth is less than or equal to 0.1 mm.

[0067] In the above-mentioned manner, the fluctuation of the height of the plurality of teeth is very small. Therefore, in the above-mentioned manner, the height of the plurality of teeth is substantially uniform, and the other end faces of the plurality of teeth can be regarded as being substantially on the same plane. If a rotating electrical machine is constructed using an iron core as described above, the other end face of the tooth portion is substantially opposite to any part of the magnet at a uniform interval, so the magnetic flux of the tooth portion receiving the magnet also becomes substantially uniform at any part, and the tooth slot torque is easily reduced. The iron core of the present invention inserts one end of the tooth portion into the through hole of the yoke portion. Therefore, by adjusting the insertion amount of one end of the tooth portion relative to the through hole, the height of each tooth portion can be easily adjusted.

[0068] (10) As an example of the iron core of (9) above,

[0069] In one embodiment, the length from the reference surface to the one end surface is less than or equal to 10% of the thickness of the yoke.

[0070] As a representative case, the thickness of the yoke is substantially uniform throughout the entire range, and the axial length of the tooth portion is substantially uniform in all the tooth portions. Therefore, the above method can uniquely determine the height of each tooth portion. The above method can fully ensure the relative area of ​​the outer peripheral surface of one end of the tooth portion and the inner peripheral surface of the through hole, so that the area of ​​the magnetic flux passing between the tooth portion and the yoke portion can be fully ensured. In addition, the above method can fully ensure the relative area of ​​the outer peripheral surface of one end of the tooth portion and the inner peripheral surface of the through hole, so it is easy to firmly fix the yoke portion and the tooth portion.

[0071] (11) As an example of the iron core of the present invention,

[0072] In one embodiment, the core is made of a material including pure iron, an iron-based alloy containing Si, or an iron-based alloy containing Al.

[0073] In the above embodiment, when the core includes pure iron, the following effects are achieved: the core is easy to be set to have a high saturation magnetic flux density, the core is easy to be set to be dense, the core is easy to be molded, and the manufacturability of the core is excellent. In the above embodiment, when the core includes an iron-based alloy, the core can be set to have a low loss.

[0074] (12) As an example of the iron core of the present invention,

[0075] In one embodiment, the relative density of the core is greater than or equal to 90%.

[0076] In the above aspect, the relative density is 90% or more, which is high and dense. The above aspect can construct an axial gap type rotating electric machine having excellent magnetic characteristics such as high saturation magnetic flux density.

[0077] (13) A stator according to one embodiment of the present invention includes:

[0078] The core of any one of (1) to (12) above; and

[0079] The coil is arranged on each of the teeth.

[0080] The stator of the present invention has the core of the present invention, so the coil can be easily mounted and the manufacturability is excellent. In addition, the stator of the present invention has the core of the present invention, so the reduction of torque can be suppressed, and an axial gap type rotating electric machine with high torque can be constructed.

[0081] (14) A rotating electrical machine according to one embodiment of the present invention includes:

[0082] The stator of the present invention; and

[0083] The rotor is arranged opposite to the stator.

[0084] The rotating electric machine of the present invention has the stator of the present invention, so the stator can be easily assembled and has excellent manufacturability. In addition, the rotating electric machine of the present invention has the stator of the present invention, so the reduction of torque can be suppressed and has high torque.

[0085] [Details of the embodiments of the present invention]

[0086] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. The same reference numerals in the drawings represent the same names. In addition, the present invention is not limited to these examples, but is shown by the claims, and is intended to include the contents equivalent to the claims and all changes within the scope thereof.

[0087] 〔Iron core〕

[0088] Appropriate reference Figure 1 to Figure 5 and Figure 6 , Figure 7, an iron core 1 of the embodiment is described. The iron core 1 has an annular yoke 3 and a plurality of columnar teeth 2. The iron core 1 is used in an axial gap type rotating electric machine (as an example, in the later described Figure 7 As a representative case, the core 1 can be used as a stator (as an example, in the rotating electrical machine 9 described later). Figure 6 The stator 8 shown in the figure is an iron core. The iron core 1 is provided with a coil 80 ( Figure 6 , Figure 7 ), is used as a source of magnetic flux generated by the coil 80, the magnet 95 ( Figure 7 ) is a component of the magnetic circuit through which the magnetic flux passes.

[0089] The iron core 1 of the embodiment is composed of a yoke 3 and each tooth 2, which are independent powder compacts. One of the characteristics of the iron core 1 of the embodiment is that the yoke 3 has a through hole 30 for inserting one end of each tooth 2, and one end of each tooth 2 is arranged in a biased manner in the through hole 30. The following is a detailed description.

[0090] 〈Yoke〉

[0091] The yoke 3 is a plate member having a circular ring shape in a plan view. The yoke 3 magnetically couples the adjacent teeth 2 arranged in the circumferential direction of the yoke 3. The yoke 3 has an axial hole 39 passing through the front and back surfaces (the first surface 31 and the second surface 32) of the yoke 3 in its central portion. The first surface 31 is a surface located on the side where the teeth 2 are convexly arranged, and the second surface 32 is the opposite surface of the first surface 31.

[0092] The yoke 3 has a through hole 30 for inserting one end of the tooth portion 2. The through hole 30 penetrates the front and back surfaces (the first surface 31 and the second surface 32) of the yoke 3. The through holes 30 are appropriately set corresponding to the number of the tooth portions 2. Since a plurality of tooth portions 2 are provided, a plurality of through holes 30 are also provided. The through holes 30 are arranged at predetermined intervals in the circumferential direction of the yoke 3. As a representative case, the hole shape and size of each through hole 30 are the same. Regarding the hole shape of the through hole 30, as a representative case, the cross-sectional shape cut by a plane parallel to the first surface 31 is similar to the outer shape of the tooth portion 2 described later. The size of the through hole 30 can be appropriately selected to be a size that can be inserted into one end of the tooth portion 2.

[0093] The yoke 3 is composed of a component independent of the tooth 2. The yoke 3 and the tooth 2 are fixed by inserting one end of the tooth 2 into the through hole 30. For example, the yoke 3 and the tooth 2 are bonded by an adhesive or the like in a state where one end of the tooth 2 is inserted into the through hole 30. In this case, the adhesive is interposed between the inner circumferential surface of the through hole 30 and the outer circumferential surface of one end of the tooth 2. The relationship between the through hole 30 of the yoke 3 and the one end of the tooth 2 will be described in detail later.

[0094] The size (outer diameter, inner diameter, thickness, etc.) of the yoke 3 can be appropriately selected in accordance with the specifications of the rotating electrical machine 9. For example, the inner diameter of the yoke 3 (the diameter of the shaft hole 39) is greater than or equal to 5 mm and less than or equal to 150 mm, the outer diameter of the yoke 3 is greater than or equal to 30 mm and less than or equal to 300 mm, and the thickness of the yoke 3 is greater than or equal to 1.0 mm and less than or equal to 10 mm, and further, it can be greater than or equal to 1.5 mm and less than or equal to 7.0 mm.

[0095] 〈Tooth〉

[0096] Each tooth portion 2 is a columnar member, and protrudes in a manner perpendicular to the first surface 31 of the yoke portion 3. In addition, each tooth portion 2 is arranged at a predetermined interval in the circumferential direction of the yoke portion 3. As a representative case, Figure 1 As shown in the example, the teeth 2 are arranged at equal intervals in the circumferential direction of the yoke 3. In addition, the direction orthogonal to the first surface 31 of the yoke 3 is equivalent to the direction parallel to the axial direction of the shaft hole 39 of the yoke 3. In addition, the axial direction of each tooth 2 is equivalent to the direction parallel to the axial direction of the yoke 3.

[0097] As a representative case, each tooth portion 2 has the same shape and size. Regarding the outer shape of the tooth portion 2, as a representative case, a prism having the same shape in the axial direction of the tooth portion 2 after being cut by a plane orthogonal to the axial direction of the tooth portion 2 is cited. The tooth portion 2 of this example is a quadrangular prism whose cross-sectional shape is a trapezoidal shape. In addition, the tooth portion 2 of this example has the same cross-sectional shape throughout the entire axial length of the tooth portion 2. The tooth portion 2 having a trapezoidal cross-sectional shape 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 easily construct a stator 8 with a high space factor. As examples of other outer shapes, a prism whose cross-sectional shape is a triangular shape such as an isosceles triangle is cited. In addition, as examples of other outer shapes, a cuboid whose cross-sectional shape is a rectangle, a cylinder whose cross-sectional shape is a circle, etc. are cited.

[0098] Here, the "trapezoidal shape" and "triangular shape" are not only geometric trapezoids and triangles, but also include shapes with chamfered corners as in this example, and include the range that can be regarded as a trapezoid or triangle in essence. For example, when the outline of the cross section includes a straight line, the shape includes the intersection points of the extended line of the straight line forming the vertices of the polygon. Or, for example, when the outline of the cross section includes a curve and a straight line, the shape includes the intersection points of the tangent line of the curve and the straight line or the extended line of the straight line forming the vertices of the polygon.

[0099] The number of teeth 2 can be selected appropriately as long as it is greater than or equal to 2. For example, the number can be greater than or equal to 3, or even greater than or equal to 6. When the core 1 is used in a three-phase AC rotating device, the number of teeth 2 is preferably a multiple of 3. Figure 1The above-mentioned number is 12 as an example.

[0100] The size (cross-sectional area, axial length, etc.) of the tooth portion 2 can be appropriately selected in accordance with the specifications of the rotary electric machine 9. For example, the cross-sectional area of ​​each tooth portion 2 is greater than or equal to 5 mm 2 Less than or equal to 800mm 2 The axial length of the tooth portion 2 is greater than or equal to 3 mm and less than or equal to 40 mm. The cross-sectional area of ​​the tooth portion 2 here refers to the area of ​​the cross section cut through a plane perpendicular to the axial direction of the tooth portion 2.

[0101] 〈Relationship between yoke and gear〉

[0102] Below, the main reference Figure 2 to Figure 5 The relationship between the through hole 30 of the yoke 3 and one end of the tooth portion 2 is described in detail.

[0103] As for the size of the through hole 30 of the yoke 3, as a representative case, in order to facilitate the insertion of the tooth 2, a margin is added and the size is designed to be larger than the size of one end of the tooth 2. As a result, a gap is generated between the outer peripheral surface 20 of one end of the tooth 2 and the inner peripheral surface 300 of the through hole 30. This gap becomes a magnetic gap, which is a cause of the reduction in torque. On the other hand, the following insight is obtained, that is, if there is a region in which the above-mentioned gap is very small in at least a part of the circumference of the through hole 30, the reduction in torque can be suppressed. It can be thought that this is because the magnetic flux passes smoothly between the tooth 2 and the yoke 3 through the region in which the above-mentioned gap is very small.

[0104] Therefore, one end of the tooth portion 2 is arranged to be biased in one direction in the through hole 30. The arrangement to be biased in one direction in the through hole 30 means that there is a region where the interval between the outer peripheral surface 20 of one end of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30 is locally small. Regarding the arrangement to be biased in one direction in the through hole 30, quantitatively speaking, it means that there is a region that satisfies less than or equal to 50% of the average value of the interval between the outer peripheral surface 20 of one end of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30. The average value of the interval between the outer peripheral surface 20 of one end of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30 is obtained, for example, by averaging the values ​​obtained by measuring 10 points or more at equal intervals in the circumferential direction of the through hole 30. In addition, when the outer shape of the tooth portion 2 and the hole shape of the through hole 30 are similar, the arrangement to be biased in one direction in the through hole 30 means that the center of gravity of the tooth portion 2 and the center of gravity of the through hole 30 do not coincide. Figure 2 The example shows a mode in which the outer shape of the tooth portion 2 and the hole shape of the through hole 30 are similar, and the center of gravity of the tooth portion 2 and the center of gravity of the through hole 30 do not coincide with each other.

[0105] The tooth portion 2 has a proximity region 25 in which the interval between the outer peripheral surface 20 of one end portion and the inner peripheral surface 300 of the through hole 30 is less than or equal to 0.05 mm. Figure 2 to Figure 5 In FIG. 1 , a portion of the region near the outer peripheral surface 20 at one end of the tooth portion 2 is cross-hatched with two-dot chain lines to virtually represent a proximity region 25. In addition, in each figure, the above-mentioned interval is shown large for easy understanding.

[0106] 《The distance between the approach area and the yoke》

[0107] The distance between the proximity region 25 of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30 of the yoke portion 3 is less than or equal to 0.05 mm, which is very small. It can be said that the proximity region 25 of the tooth portion 2 as described above is a region substantially in contact with the inner peripheral surface 300 of the through hole 30. Therefore, it can be said that the gap that may be formed between the proximity region 25 of the tooth portion 2 and the yoke portion 3 is unlikely to become a magnetic gap. If the rotating electric machine 9 ( Figure 7 ), it is possible to ensure that the magnetic flux between the tooth portion 2 and the yoke portion 3 passes better through the proximity region 25 of the tooth portion 2. Therefore, the rotary electric machine 9 is more likely to suppress the reduction of torque and is likely to have a high torque.

[0108] The smaller the interval between the approach region 25 of the tooth portion 2 and the inner circumferential surface 300 of the through hole 30 of the yoke portion 3, the easier it is to ensure that the magnetic flux between the tooth portion 2 and the yoke portion 3 passes through the approach region 25. In the case where it is desired to further suppress the reduction in torque, the above interval is preferably less than or equal to 0.04 mm, more preferably less than or equal to 0.03 mm, less than or equal to 0.02 mm. The core 1 may also have an area where the above interval is substantially 0 mm.

[0109] 《Joint ratio》

[0110] The approach region 25 of the tooth portion 2 is preferably as long as possible. Quantitatively speaking, it is preferred that the ratio of the length L25 of the approach region 25 along the circumferential direction of the through hole 30 to the circumferential length L30 of the through hole 30 (hereinafter referred to as the engagement ratio) is greater than or equal to 20%. The engagement ratio (%) is obtained by (L25 / L30)×100.

[0111] If the above-mentioned engagement ratio is greater than or equal to 20%, it can be said that the proximity region 25 of the tooth portion 2 is long. Therefore, it is easy to ensure that the magnetic flux between the tooth portion 2 and the yoke portion 3 passes better through the proximity region 25. In the case of further suppressing the reduction of torque, the above-mentioned engagement ratio is preferably greater than or equal to 25%, more preferably greater than or equal to 30%, or greater than or equal to 35%.

[0112] The above-mentioned joining ratio is preferably as large as possible within a range of less than 100%. On the other hand, if the above-mentioned joining ratio is, for example, less than or equal to 70%, it is easy to ensure a large margin for the insertion operation of the tooth portion 2 into the through hole 30, and the assembly workability of the tooth portion 2 and the flange portion 5 is excellent. In the case of improving the assembly workability, the above-mentioned joining ratio can be set to less than or equal to 65%, and can also be set to 60%.

[0113] The maximum difference between intervals

[0114] By arranging one end of the tooth portion 2 in a biased manner in the through hole 30, a region where the interval between the outer peripheral surface 20 of the one end of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30 is relatively large is sometimes generated. In this case, it is also preferable that the difference between the maximum value and the minimum value of the above-mentioned interval (hereinafter, this difference is referred to as the maximum difference of the interval) is less than 0.40 mm. If the maximum difference of the above-mentioned interval is less than 0.40 mm, it can be said that the core 1 does not have a region where the interval between the outer peripheral surface 20 of the one end of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30 is locally large. The region where the above-mentioned interval is locally large becomes a large magnetic gap. Therefore, if the maximum difference of the above-mentioned interval is less than 0.40 mm, the core 1 does not have a large magnetic gap, and it is easy to ensure that the magnetic flux between the tooth portion 2 and the yoke portion 3 passes well. Therefore, it is easy to suppress the reduction of torque. The smaller the maximum difference of the above-mentioned interval is, the more clearly the core 1 does not have a large magnetic gap, and it is easy to ensure that the magnetic flux between the tooth portion 2 and the yoke portion 3 passes well. When it is desired to further suppress the reduction in torque, the maximum difference in the above-mentioned intervals is preferably equal to or less than 0.35 mm, and more preferably equal to or less than 0.30 mm.

[0115] 《Location of the proximity area》

[0116] The tooth portion 2 has an approach region 25 at any position in the circumferential direction of the through hole 30 of the yoke portion 3. Figure 2 As shown in the example, the tooth portion 2 may also have at least a portion of the proximity region 25 on the outer peripheral side of the yoke portion 3 in the tooth portion 2. In this case, it is easy to set the proximity region 25 to be long. For example, the outer shape of the tooth portion 2 is a trapezoid. If the long side of the trapezoid is located on the outer peripheral side of the yoke portion 3, the length of the outer peripheral region 26 of the tooth portion 2 located on the outer peripheral side of the yoke portion 3 is longer than the length of the inner peripheral region 27 of the tooth portion 2 located on the inner peripheral side of the yoke portion 3. Therefore, if at least a portion of the proximity region 25 is provided in the outer peripheral region 26 of the tooth portion 2, it is easy to ensure that the proximity region 25 is long. The longer the proximity region 25 is, the greater the above-mentioned joining ratio is. As a result, the core 1 can easily ensure that the magnetic flux between the tooth portion 2 and the yoke portion 3 passes well via the proximity region 25, and it is easier to suppress the reduction of torque.

[0117] exist Figure 22 shows an example of a case where the proximity region 25 is provided in an L-shape over the outer peripheral region 26 of the tooth portion 2 and the region on one side of the yoke portion 3 in the tooth portion 2. In addition, the core 1 may have the proximity region 25 only in the outer peripheral region 26 of the tooth portion 2. Alternatively, the core 1 may have the proximity region 25 only in the inner peripheral region 27 of the tooth portion 2 or only in the region on one side of the yoke portion 3 in the tooth portion 2.

[0118] It is preferred that the tooth portion 2 has at least a portion of the proximity region 25 in the outer peripheral region 26 of the tooth portion 2, and the above-mentioned engagement ratio is greater than or equal to 20%.

[0119] In addition, as in Figure 3 As shown in the example, the following case is given, that is, in the teeth 2 adjacent to each other in the circumferential direction of the yoke 3, at least a part of the proximity region 25 is provided on the opposite sides of the two teeth 2. In this case, the proximity regions 25 of the adjacent teeth 2 are opposite to each other. Therefore, the adjacent teeth 2 can easily ensure good passage of magnetic flux through the proximity regions 25 of each tooth 2.

[0120] When the core 1 having the adjacent teeth 2 with the proximity region 25 as described above is used in a multi-phase AC rotating electric machine, the coils 80 ( Figure 6 , Figure 7 ), the coils 80 of different phases may also be arranged. In particular, if the coils 80 of the same phase are arranged on adjacent teeth 2, it is easier to suppress the reduction of torque than when the coils 80 of different phases are arranged. For example, when the core 1 is used in a three-phase AC rotating motor, Figure 3 From the left side of the , U-phase coils (not shown) are arranged at the first tooth 2 and the second tooth 2, V-phase coils (not shown) are arranged at the third tooth 2 and the fourth tooth 2, and W-phase coils (not shown) are arranged at the fifth tooth 2 and the sixth tooth 2 (not shown). In this case, the tooth 2 with coils 80 of different phases arranged for adjacent tooth 2, for example, Figure 3 The second tooth portion 2 and the third tooth portion 2 from the left side of the tooth portion 2 are arranged with the proximity region 25 being arranged on the sides where the two tooth portions 2 are away from each other.

[0121] In addition, if Figure 4 As shown in the example, the tooth portion 2 may have at least a portion of the proximity region 25 on the same side of the yoke portion 3 in the circumferential direction of the tooth portion 2. In this case, it is easy to ensure that the magnetic flux passes through the proximity region 25 of each tooth portion 2. In addition, in this case, it is expected that the magnetic flux passing through the proximity region 25 of each tooth portion 2 will easily become the same, the magnetic flux will not be easily disturbed, and the torque pulsation will also be easily reduced. Moreover, in this case, the fixing state of each tooth portion 2 to each through hole 30 of the yoke portion 3 can be made the same. This structure is also excellent in the manufacturability of the core 1 due to this point. In addition, in Figure 4 2 shows an example in which a part of the proximity region 25 is provided on the right side of each tooth portion 2 .

[0122] When the rotating electrical machine 9 is constructed using the core 1 having the proximity regions 25 of the teeth 2 on the same side in the circumferential direction of the yoke 3, the teeth 2 can be located on the same side as the rotor 90 ( Figure 7 ) and any side opposite to the rotation direction has a proximity region 25. In particular, if each tooth portion 2 has a proximity region 25 on the same side as the rotation direction, it is easier to suppress the reduction of torque than if it has a proximity region 25 on the opposite side.

[0123] "High Fluctuation"

[0124] The yoke 3 and the teeth 2 are formed of independent parts, so that the height of the plurality of teeth 2 relative to the yoke 3 may fluctuate. Even in this case, it is preferred that the fluctuation of the height of the plurality of teeth 2 relative to the yoke 3 is less than or equal to 0.1 mm. Figure 5 As shown, the second surface 32 of the extended yoke 3 is set as the reference plane, and the length H1 from the reference plane to the other end surface 22 of the tooth 2. If the fluctuation of the height is less than or equal to 0.1 mm, it can be regarded that the other end surfaces 22 of the plurality of teeth 2 are substantially in the same plane. If the rotating electric machine 9 is constructed using the core 1 as described above, the other end surface 22 of the tooth 2 and the magnet 95 ( Figure 7 ) are substantially opposed at uniform intervals at any position. Therefore, the magnetic flux of the receiving magnet 95 of the tooth portion 2 becomes substantially uniform at any position, which makes it easy to reduce the cogging torque.

[0125] By adjusting the insertion amount of one end of the tooth 2 relative to each through hole 30, the height of each tooth 2 can be easily adjusted. For example, one end of the tooth 2 can be inserted into the through hole 30 in such a manner that the length H3 from the reference plane to the one end face 21 of the tooth 2 is less than or equal to 10% of the thickness H2 of the yoke 3. In other words, the insertion amount (H2-H3) of the one end of the tooth 2 relative to the through hole 30 can be set to be greater than or equal to 90% of the thickness H2 of the yoke 3. As a representative case, the thickness H2 of the yoke 3 is substantially uniform over the entire range, and the axial length of the tooth 2 is substantially uniform in all teeth 2. Thus, by specifying the insertion amount of one end of the tooth 2 relative to the through hole 30, the height of each tooth 2 can be uniquely determined. The above method can fully ensure the relative area of ​​the outer peripheral surface 20 of one end of the tooth 2 and the inner peripheral surface 300 of the through hole 30, and thus can fully ensure the area of ​​the magnetic flux passing between the tooth 2 and the yoke 3. In addition, the above-described embodiment can sufficiently ensure the facing area between the outer peripheral surface 20 of one end portion of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30 , and thus the yoke portion 3 and the tooth portion 2 can be easily firmly fixed.

[0126] 〈Constitutional Materials〉

[0127] The constituent material of the core 1 includes a soft magnetic material. Typically, the core 1 is mainly composed of a soft magnetic material. Examples of the soft magnetic material include pure iron and an iron-based alloy.

[0128] Here, pure iron refers to a purity greater than or equal to 99%, that is, the content of Fe (iron) is greater than or equal to 99% by mass. Pure iron has the effects of high saturation flux density, excellent formability, and easy densification by compression molding. Therefore, if pure iron is included, it is possible to realize an iron core 1 with high saturation flux density, a dense iron core 1 with high relative density, and an iron core 1 with excellent manufacturability that is easy to form during the manufacturing process. In addition, due to the density, it is easy to further increase the saturation flux density, and it is possible to realize an iron core 1 with excellent mechanical properties such as strength.

[0129] The iron-based alloy here contains additive elements, and the remainder is composed of Fe and inevitable impurities. The iron-based alloy contains one or more than or equal to two additive elements. Examples of additive elements include Si (silicon), Al (aluminum), Cr (chromium), etc. Specific examples of iron-based alloys include iron-based alloys containing Si (Fe-Si alloys), iron-based alloys containing Al (Fe-Al alloys), and iron-based alloys containing Cr on the basis of Si or Al. The electrical resistance of iron-based alloys is greater than that of pure iron. Therefore, if an iron-based alloy is included, the following iron core 1 can be realized, which can reduce iron losses such as eddy current losses and has low losses. It can also be set as an iron core 1 containing both pure iron and an iron-based alloy.

[0130] The powder compact constituting the yoke 3 and the powder compact constituting the tooth portion 2 are both aggregates of powder particles consisting of a soft magnetic material. The powder compact is mainly formed by meshing the powder particles with each other through plastic deformation to maintain a predetermined shape. As a representative case, the powder compact can be manufactured by compression molding a raw material powder containing powder consisting of a soft magnetic material using a mold (not shown).

[0131] The soft magnetic powder may include coated particles having an insulating coating on the surface of powder particles composed of a soft magnetic material. If the coated particles are included, the following iron core 1 can be realized, which can reduce iron losses such as eddy current loss and has low loss. It can also be set as an iron core 1 containing both pure iron and iron-based alloy. In particular, if the coated particles having powder particles composed of pure iron and insulating coating are included, the following iron core 1 can be realized, which has a high saturation flux density, excellent magnetic properties, and low loss. The constituent materials of the insulating coating include, for example, oxides such as phosphates and silicon dioxide. Phosphates have excellent adhesion to powder particles composed of iron or iron-based alloys, and are also excellent in deformability. Therefore, the insulating coating composed of phosphates is easy to deform following the deformation of the above-mentioned iron powder particles during molding and is not easily damaged. Therefore, a compressed powder molded body with a sound insulating coating can be manufactured. By having a compressed powder molded body as described above, a low-loss iron core 1 can be realized.

[0132] 〈Relative density〉

[0133] If the relative density of the core 1 is high and dense, the magnetic properties such as saturation magnetic flux density and mechanical properties such as strength are excellent, which is preferred. Quantitatively speaking, the relative density of the yoke 3 and the relative density of the tooth 2 are preferably greater than or equal to 90%. If the above relative density is greater than or equal to 90%, it is possible to achieve an iron core 1 with a high saturation magnetic flux density and excellent strength. For example, by fixing one end of the tooth 2 in the through hole 30 of the yoke 3, defects of the yoke 3 and the tooth 2 can be prevented. In the case of wishing to improve the magnetic properties, improve the mechanical properties, etc., it is preferred that the above relative density is greater than or equal to 93%, and more preferably greater than or equal to 95%.

[0134] The relative density here refers to the ratio (%) of the actually measured density of the powder molded body to the theoretical density of the powder molded body constituting the core 1. The theoretical density can be equivalent to the true density of the soft magnetic material constituting the powder molded body.

[0135] <other>

[0136] The core 1 can be cited as having the other end surface 22 ( Figure 5) has a flange (not shown). The flange is formed to protrude from the periphery of the other end face 22 of the tooth portion 2 to the outer peripheral side and has a larger area than the other end face 22. If the iron core 1 having the flange on the tooth portion 2 is used to form a rotating electric machine 9 ( Figure 7 ), the area facing the magnet 95 increases, and the interlinked magnetic flux increases. This can reduce the cogging effect and improve the characteristics of the rotating electrical machine 9. In addition, the flange can prevent the coil 80 ( Figure 6 ) falls off from tooth portion 2.

[0137] The flange portion may be formed of a powder compact integrally formed with the tooth portion 2, or may be formed of a powder compact independent of the tooth portion 2. When the tooth portion 2 and the flange portion are formed of independent powder compacts, the connection between the tooth portion 2 and the flange portion may be, for example, by connecting the other end surface 22 ( Figure 5 ) and the lower surface of the flange portion are bonded by an adhesive. In addition, a convex portion or a concave portion may be provided on the other end surface 22 of the tooth portion 2, and a concave portion or a convex portion corresponding to the convex portion or the concave portion may be provided on the lower surface of the flange portion, thereby connecting the tooth portion 2 and the flange portion by fitting the convex portion and the concave portion on the basis of the adhesive. The concave portion includes a through hole.

[0138] <Manufacturing method>

[0139] The powder compact constituting the yoke 3 and the powder compact constituting the tooth portion 2 can be manufactured by compressing the raw material powder into a predetermined shape as described above. In the case of a flange portion that is independent of the yoke 3 and the tooth portion 2, the powder compact constituting the flange portion can also be manufactured in the same manner. A stamping machine or the like can be used for compression molding. The raw material powder can further include a binder and a lubricant on the basis of the powder of the soft magnetic material. A lubricant can be applied to the mold.

[0140] The average particle size of the powder of the soft magnetic material used as the raw material powder can be, for example, greater than or equal to 20 μm and less than or equal to 350 μm. If the average particle size of the above-mentioned powder is within the above-mentioned range, it is easy to handle the above-mentioned powder and easy to compress and mold. The average particle size of the above-mentioned powder can be greater than or equal to 40 μm and less than or equal to 300 μm, and can further be less than or equal to 250 μm. The average particle size of the above-mentioned powder here is set to be a particle size at which the cumulative mass becomes 50% of the mass of all particles when measured using a laser diffraction / scattering particle size distribution measuring device.

[0141] The higher the pressure during compression molding, the easier it is to densify, and the higher the relative density of the core 1 can be produced. The pressure is, for example, 700 MPa or more, and further 980 MPa or more.

[0142] After compression molding, heat treatment may be performed as needed. For example, strain may be removed by heat treatment, thereby manufacturing a low-loss iron core 1. Alternatively, for example, a binder or lubricant may be removed by heat treatment. When the raw material powder includes the above-mentioned coated particles, the heat treatment temperature is preferably less than or equal to the decomposition temperature of the insulating coating.

[0143] <Main functions and effects of implementation methods>

[0144] The yoke 3 and teeth 2 of the core 1 of the embodiment are formed of independent powder compacts. Therefore, the core 1 can arrange the coil 80 on the teeth 2 before being fixed to the yoke 3. The stator and axial gap type rotating electric machine having the core 1 as described above are excellent in manufacturability.

[0145] In particular, in the iron core 1 of the embodiment, regarding the fixing of the tooth portion 2 to the yoke portion 3, one end portion of the tooth portion 2 is arranged to one side in the through hole 30 formed in the yoke portion 3. That is, the iron core 1 has a region where the interval between the outer peripheral surface 20 of one end portion of the tooth portion 2 and the inner peripheral surface 300 of the through hole 30 is locally small. Thus, the iron core 1 can form a region with a small gap that becomes a magnetic gap between the tooth portion 2 and the yoke portion 3, and the magnetic flux between the tooth portion 2 and the yoke portion 3 can be ensured to pass well through the region with a small gap. Therefore, the iron core 1 can suppress the reduction of torque, and can construct an axial gap type rotating electric machine with high torque.

[0146] 〔stator〕

[0147] Reference Figure 6 The stator 8 of the embodiment is described. The stator 8 includes: an iron core 1; and a coil 80 disposed on each tooth portion 2 of the iron core 1. The stator 8 is used in an axial gap type rotating electric machine (for example, a rotating electric machine 9 ( Figure 7 )) is used in Figure 6 For example, Figure 1 The situation of the core 1 shown.

[0148] Each coil 80 has a cylindrical portion formed by winding the winding wire in a spiral shape. The coil 80 of this example is an edgewise wound coil in which the winding wire is made into a square cylindrical shape with a flat wire wrapped around it. Figure 6 Only the cylindrical portion is shown, and both end portions of the winding wire are omitted from the illustration.

[0149] The stator 8 of the embodiment has the iron core 1 of the embodiment in which the yoke 3 and the tooth 2 are independent of each other. Therefore, by separately manufacturing the coil 80 and embedding the coil 80 on the outer side of the tooth 2 before fixing the yoke 3, the coil 80 can be easily arranged on each tooth 2. After the coil 80 is inserted through the tooth 2, one end of each tooth 2 is fixed to the yoke 3, thereby making the stator 8. In the manufacturing process of the stator 8 using the iron core 1 as a component, the winding process of the winding and the configuration process of the coil 80 on the tooth 2 can be set as independent processes. Therefore, it is not necessary to directly wind the winding on each tooth 2. Therefore, it is easy to wind the winding, and the manufacturability of the coil 80 is also excellent. In addition, if the flange portion is not integrally formed on the tooth 2, the tooth 2 can also be fixed to the yoke 3, and the coil 80 can be embedded on the outer side of the tooth 2 fixed to the yoke 3.

[0150] Since the stator 8 of the embodiment includes the iron core 1 of the embodiment, it is possible to suppress a decrease in torque and to construct an axial gap type rotating electrical machine having a high torque.

[0151] 〔Rotating electric machine〕

[0152] Reference Figure 7 , the rotating electrical machine 9 according to the embodiment will be described. Figure 7 This is a cross-sectional view taken along a plane parallel to the rotating shaft 91 of the rotary electric machine 9 .

[0153] The rotating electric machine 9 of the embodiment has the stator 8 of the embodiment. Specifically, the rotating electric machine 9 has a rotor 90 and a stator 8, and is an axial gap type rotating electric machine in which the rotor 90 and the stator 8 are arranged to face each other in the axial direction. The rotating electric machine 9 as described above can be used as a motor or a generator. Figure 7 The single rotor and double stator structures are illustrated in which one rotor 90 is assembled by sandwiching two stators 8. In addition, a form having one rotor 90 and one stator 8, a form in which one stator 8 is assembled by sandwiching two rotors 90, etc. are given as examples.

[0154] The stator 8 and the rotor 90 are housed in a housing 92 having a cylindrical internal space. The housing 92 has a cylindrical portion and two plate portions. The cylindrical portion surrounds the outer circumference of the stator 8 and the rotor 90. Plate portions are respectively arranged on both sides of the cylindrical portion. The stator 8 and the rotor 90 are housed in the housing 92 in a manner sandwiched by the two plate portions. The stator 8 is fixed to the housing 92 by embedding the outer circumferential surface of the yoke 3 of the core 1 into the plate portion of the housing 92. The two plate portions have a through hole in their center portion. A bearing 93 is provided in the through hole, and the rotating shaft 91 is inserted through the bearing 93. In addition, a bearing (not shown) is also provided in the shaft hole 39 of the yoke 3, and the rotating shaft 91 is inserted through the bearing. The rotating shaft 91 passes through the housing 92.

[0155] The rotor 90 is a flat plate-shaped member having a plurality of magnets 95 and a rotor body supporting the magnets 95. Each magnet 95 has, for example, a portion of the rotor body having a contact with the other end surface ( Figure 5 ) in a planar shape corresponding to the planar shape of the rotor body. The rotor body is an annular member, which is rotatably supported by the rotating shaft 91. The magnets 95 are arranged at equal intervals in the circumferential direction of the rotor body. In addition, the magnets 95 are magnetized in the axial direction of the rotating shaft 91. The magnetization directions of the magnets 95 adjacent to each other in the circumferential direction of the rotor body are opposite to each other. If the rotor body rotates, the magnets 95 also rotate together with the rotor body.

[0156] The stator 8 is configured as the other end surface 22 ( Figure 5 ) is opposite to the magnet 95 of the rotor 90. The coil 80 of the stator 2 is excited to generate a rotating magnetic field, and the rotor 90 rotates relative to the stator 8 by the attraction or rebound force caused by the rotating magnetic field. When the rotor 90 rotates, the other end surface 22 ( Figure 5 ) receives magnetic flux from the rotating magnet 95.

[0157] The rotating electric machine 9 of the embodiment has the stator 8 of the embodiment. As described above, the stator 8 is easy to assemble, so the manufacturability of the rotating electric machine 9 is excellent. In addition, the rotating electric machine 9 of the embodiment has the stator 8 of the embodiment, so it can suppress the reduction of torque and has high torque.

[0158] [Test example]

[0159] The torque when an iron core including an annular yoke and a plurality of teeth is applied to a stator of a three-phase AC axial gap motor was investigated by simulation.

[0160] In the following experiments, analysis was performed using electromagnetic field analysis software ("JMAG" manufactured by JSOL). The models of the iron cores used in the simulation all have a constituent material of pure iron and a pressed powder molded body with a relative density greater than or equal to 90%. The outer shape of the tooth portion and the hole shape of the through hole formed in the yoke portion are both similar trapezoidal shapes. In the tooth portion, the long side of the trapezoid is arranged on the outer peripheral side of the yoke portion. The size of each iron core is set to be substantially the same size. In addition, in each of the following tests, except for the different points in which the relationship between one end of the tooth portion and the through hole is different, the energization conditions of the coil arranged on the tooth portion and the rotation conditions of the magnet arranged on the other end face of the tooth portion are set to be the same and the torque is investigated.

[0161] [Test Example 1]

[0162] In this test, the influence of the yoke and the teeth on the torque due to the presence or absence of division of the yoke and the teeth was investigated for a model of an iron core having a yoke and teeth.

[0163] (Description of sample)

[0164] The core of sample No. 100 is an ideal shape in which the yoke and the teeth are integrally formed. The core of sample No. 100 is not an assembly of multiple split pieces, but an integrally formed product, and there is no gap between the yoke and the teeth that could become a magnetic gap.

[0165] The core of sample No. 101 is a core in which the yoke and the tooth are separated, compared to the ideal core of sample No. 100. A through hole is formed in the yoke, and one end of the tooth is arranged in the through hole. The core of sample No. 101 has a gap that can become a magnetic gap between the outer circumference of one end of the tooth and the inner circumference of the through hole of the yoke. The gap is set to the same interval in the circumferential direction of the through hole, and the above interval is set to 0.1 mm.

[0166] The core of sample No. 1 is a core in which the yoke and the tooth are separated, relative to the ideal core of sample No. 100. A through hole is formed in the yoke, and one end of the tooth is arranged in one direction in the through hole. The core of sample No. 1 has a gap that can become a magnetic gap between the outer circumferential surface of one end of the tooth and the inner circumferential surface of the through hole of the yoke. The above-mentioned gap has a locally small interval in the circumferential direction of the above-mentioned through hole. Regarding the interval between the outer circumferential surface of one end of the tooth and the inner circumferential surface of the through hole, the average value of the values ​​obtained by measuring 10 points at equal intervals in the circumferential direction of the through hole is 0.1mm. In addition, the above-mentioned locally small interval is 0mm. The area with this locally small interval (close area) is L-shaped in the range of the outer circumferential side of the yoke in the tooth and the opposite side of the adjacent tooth. Coils of the same phase are arranged in adjacent teeth. The ratio of the length of the close area along the circumferential direction of the through hole to the circumferential length of the through hole (joining ratio) is 22%. Regarding the core of sample No. 1, when observing each tooth portion, the length from the extended surface of the surface of the yoke portion on the side opposite to the protruding side of the tooth portion to the end surface of each tooth portion located in the through hole is 0% of the thickness of the yoke portion. In other words, the surface of the yoke portion on the side opposite to the protruding side of the tooth portion and the end surface of each tooth portion located in the through hole are coplanar. In addition, in the core of sample No. 1, the fluctuation of the height of multiple teeth is 0 mm.

[0167] (Test conditions)

[0168] In this test, a motor having the following stator core was assumed, and the torque of the motor was studied.

[0169] (Conditions of stator core)

[0170] The number of coil turns is 30, and the cross-sectional area of ​​the teeth is 102mm 2 , 14 poles and 12 slots

[0171] The outer diameter of the yoke is 100mm and the inner diameter of the yoke is 70mm

[0172] The torque (N·m) of each sample is shown in Table 1. In addition, the torque reduction rate (%) of each sample was calculated based on the torque of sample No. 100. The torque reduction rate was calculated by {(torque of each sample - torque of sample No. 100) / torque of sample No. 100}×100. The torque reduction rate (%) is also shown in Table 1.

[0173] [Table 1]

[0174]

[0175] As shown in Table 1, it can be seen that the reduction rate of the torque of the core of sample No. 1 relative to sample No. 100 is smaller than that of sample No. 101, and it has a high torque. One of the reasons for this is that the core of sample No. 1 is configured with the teeth biased to one side in the through hole, so that a small gap area between the teeth and the yoke can be formed, which becomes a magnetic gap. It can be imagined that although the torque of the core of sample No. 1 is slightly worse than that of the core of sample No. 100, the torque reduction rate is suppressed to less than or equal to 5%, so a rotating motor with high torque can be constructed. The core of sample No. 1 is constructed in that the yoke and the teeth are independently constructed, so the coil can be arranged on the teeth before being fixed to the yoke. Therefore, it is expected that the stator and axial gap type rotating motor having the core of sample No. 1 are excellent in manufacturability.

[0176] [Test Example 2]

[0177] In this test, the difference between the maximum and minimum values ​​of the interval between the outer peripheral surface of one end of the tooth portion and the inner peripheral surface of the through hole of the yoke portion (hereinafter referred to as the maximum difference in the interval) was changed with respect to the core of sample No. 1 used in Test Example 1. The influence of the difference in the maximum difference in the interval on the torque was investigated.

[0178] One end of the tooth portion is arranged in a biased manner in the through hole in such a manner as to satisfy the maximum difference of the intervals shown in Table 2. The minimum value of the above interval is 0 mm, and the maximum value of the above interval is equal to the maximum difference of the intervals shown in Table 2. The maximum value of the above interval is increased by enlarging the size of the through hole of the yoke. In addition, the ratio of the length of the proximity area along the circumferential direction of the through hole to the circumference of the through hole (joining ratio) is 25%.

[0179] The torque (N·m) of each sample is shown in Table 2. In addition, similarly to Test Example 1, the torque reduction rate (%) of each sample was determined using the torque of Sample No. 100 as a reference. The results are shown in Table 2.

[0180] [Table 2]

[0181]

[0182] As shown in Table 3, it can be seen that any core of sample No. 2 and sample No. 3 also has a small torque reduction rate relative to the core of sample No. 100, and has a high torque. In particular, it can be seen that the torque reduction rate of the core of sample No. 3, whose maximum difference in spacing is 0.30 mm, is less than or equal to 4%, and has a higher torque. As one of the reasons, it can be thought that in the core of sample No. 3, the gap between the outer peripheral surface of one end of the tooth portion and the inner peripheral surface of the through hole of the yoke portion is not easy to become a magnetic gap. According to the test, the following situation is shown, that is, if the maximum difference in spacing is less than 0.40 mm, preferably less than or equal to 0.30 mm, the reduction in torque can be effectively suppressed, and it is easy to have a high torque.

[0183] [Test Example 3]

[0184] In this test, the ratio of the length of the proximity region along the circumferential direction of the through hole to the circumferential length of the through hole (joint ratio) was changed compared to the core of Sample No. 3 used in Test Example 2. The influence of the difference in the joint ratio on the torque was investigated.

[0185] The maximum difference in the interval of the core of sample No. 4 used in this test was 0.30 mm. In addition, the core of sample No. 4 had a close region on the outer peripheral side of the yoke portion in the tooth portion, and the above-mentioned joining ratio of the close region was 20%.

[0186] The torque (N·m) of sample No. 4 is shown in Table 3. In addition, similarly to Test Example 1, the torque reduction rate (%) of sample No. 4 was determined with reference to the torque of sample No. 100. The results are shown in Table 3.

[0187] [Table 3]

[0188]

[0189] As shown in Table 3, it can be seen that the core of sample No. 4 has a small reduction rate of torque relative to the core of sample No. 100, and has a high torque. If compared with the core of sample No. 3 having the same maximum difference in interval, it can be seen that the one with a larger engagement ratio has a higher torque. One of the reasons for this is that since the approach area of ​​the tooth portion is long, the passage of the magnetic flux between the tooth portion and the yoke portion can be ensured to be better through the approach area of ​​the tooth portion. According to the test, the following situation is shown, that is, if the engagement ratio of the approach area is greater than or equal to 20%, preferably greater than or equal to 25%, in the case of having an approach area, the reduction of torque can be effectively suppressed, and it is easy to have a high torque.

[0190] [Test Example 4]

[0191] In this test, the proximity regions were provided with a spacing of 0.05 mm or less and the positions of the proximity regions were changed as in Test Example 2. The influence of the position of the proximity regions and the rotation direction of the rotor on the torque was investigated.

[0192] The maximum difference in the distance between the cores of each sample used in this test was 0.30 mm. In addition, the bonding ratio of the proximal region of the cores of each sample was 53%.

[0193] The cores of samples No. 5 and No. 6 have close regions on the opposite sides of the teeth in the adjacent teeth. That is, the close regions of the adjacent teeth are arranged relative to each other. In the core of sample No. 5, coils of different phases are arranged in the adjacent teeth. In the core of sample No. 6, coils of the same phase are arranged in the adjacent teeth.

[0194] The cores of samples No. 7 and No. 8 have the proximity regions of the teeth on the same side of the yoke in the circumferential direction. The core of sample No. 7 has the proximity regions of the teeth on the same side as the rotation direction of the rotor. The core of sample No. 8 has the proximity regions of the teeth on the side opposite to the rotation direction of the rotor.

[0195] The torque (N·m) of each sample is shown in Table 4. In addition, similarly to Test Example 1, the torque reduction rate (%) of each sample was determined using the torque of Sample No. 100 as a reference. The results are shown in Table 4.

[0196] [Table 4]

[0197]

[0198] As shown in Table 4, it can be seen that any of the cores of Samples No. 5 to No. 8 also have a relatively small reduction rate of torque relative to Sample No. 100, and have high torque. One of the reasons for this is that any of the cores of Samples No. 5 to No. 8 also have a proximity area, so that the passage of magnetic flux can be ensured to be good through the proximity area. According to this test, it can be said that in the case where adjacent teeth have proximity areas on opposite sides of the teeth, if coils of the same phase are arranged on each tooth, it is easy to further suppress the reduction of torque (refer to Sample No. 6). In addition, according to this test, it can be said that in the case where there are proximity areas of each tooth on the same side of the circumference of the yoke, if the configuration position of the proximity area is on the same side as the rotation direction of the rotor, it is easy to further suppress the reduction of torque (refer to Sample No. 7).

[0199] As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment, Various deformation|transformation is possible within the range described in a claim.

[0200] Description of the label

[0201] 1 Core

[0202] 2 Teeth

[0203] 20 Outer Surface

[0204] 21 One end face

[0205] 22 The other end

[0206] 25 Approach Area

[0207] 26 Peripheral area

[0208] 27 Inner perimeter area

[0209] 3 yoke

[0210] 30 Through hole

[0211] 300 Inner Surface

[0212] 31 Page 1

[0213] 32 Side 2

[0214] 39 Axis hole

[0215] 8 Stator

[0216] 80 Coil

[0217] 9 Rotating motor

[0218] 90 rotor

[0219] 91 Rotation axis

[0220] 92 Shell

[0221] 93 Bearings

[0222] 95 Magnet

Claims

1. An iron core used in an axial gap type rotating electrical machine, The core has: an annular yoke having a plurality of through holes arranged in a circumferential direction; and a plurality of columnar teeth, which are arranged in the circumferential direction of the yoke, and one end of each of which is inserted into the plurality of through holes, The yoke and the teeth are formed of independent powder compacts. The one end portion of each tooth portion is arranged in a biased manner in the through hole, Each tooth portion has: A proximity region in which the interval between the outer circumferential surface of the one end portion and the inner circumferential surface of the through hole is less than or equal to 0.05 mm; and A non-approaching area in which the interval between the outer circumferential surface of the one end portion and the inner circumferential surface of the through hole is greater than 0.05 mm and less than 0.45 mm, At least a part of the proximity region is provided on the outer peripheral side of the yoke portion in each of the tooth portions.

2. The core according to claim 1, wherein: A ratio of a length of the proximity region along a circumferential direction of the through hole to a circumferential length of the through hole is greater than or equal to 20% and less than or equal to 70%.

3. The core according to claim 1, wherein: Each of the teeth has one end surface located inside the through hole and another end surface located outside the through hole. The yoke has a first surface located on the protruding side of each tooth portion, and a second surface opposite to the first surface. When a surface obtained by extending the second surface is defined as a reference surface and a length from the reference surface to the other end surface is defined as a height of each tooth portion, A fluctuation in height of the plurality of teeth is less than or equal to 0.1 mm.

4. The core according to claim 3, wherein: A length from the reference plane to the one end surface is less than or equal to 10% of a thickness of the yoke.

5. The core according to claim 1, wherein: The iron core is made of materials including pure iron, an iron-based alloy containing Si, or an iron-based alloy containing Al.

6. The core according to claim 1, wherein: The relative density of the iron core is greater than or equal to 90%.

7. An iron core used in an axial gap type rotating electrical machine, The core has: an annular yoke having a plurality of through holes arranged in a circumferential direction; and a plurality of columnar teeth, which are arranged in the circumferential direction of the yoke, and one end of each of which is inserted into the plurality of through holes, The yoke and the teeth are formed of independent powder compacts. The one end portion of each tooth portion is arranged in a biased manner in the through hole, Each tooth portion has: A proximity region in which the interval between the outer circumferential surface of the one end portion and the inner circumferential surface of the through hole is less than or equal to 0.05 mm; and A non-approaching area in which the interval between the outer circumferential surface of the one end portion and the inner circumferential surface of the through hole is greater than 0.05 mm and less than 0.45 mm, The respective tooth portions have at least a part of the approach region on the same side in the circumferential direction of the yoke portion.

8. The core according to claim 7, wherein: A ratio of a length of the proximity region along a circumferential direction of the through hole to a circumferential length of the through hole is greater than or equal to 20% and less than or equal to 70%.

9. The core according to claim 7, wherein: Each of the teeth has one end surface located inside the through hole and another end surface located outside the through hole. The yoke has a first surface located on the protruding side of each tooth portion, and a second surface opposite to the first surface. When a surface obtained by extending the second surface is defined as a reference surface and a length from the reference surface to the other end surface is defined as a height of each tooth portion, A fluctuation in height of the plurality of teeth is less than or equal to 0.1 mm.

10. The core according to claim 9, wherein: A length from the reference plane to the one end surface is less than or equal to 10% of a thickness of the yoke.

11. The core according to claim 7, wherein: The iron core is made of materials including pure iron, an iron-based alloy containing Si, or an iron-based alloy containing Al.

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

13. An iron core used in an axial gap type rotating electrical machine, The core has: an annular yoke having a plurality of through holes arranged in a circumferential direction; and a plurality of columnar teeth, which are arranged in the circumferential direction of the yoke, and one end of each of which is inserted into the plurality of through holes, The yoke and the teeth are formed of independent powder compacts. The one end portion of each tooth portion is arranged in a biased manner in the through hole, Each tooth portion has: A proximity region in which the interval between the outer circumferential surface of the one end portion and the inner circumferential surface of the through hole is less than or equal to 0.05 mm; and A non-approaching area in which the interval between the outer circumferential surface of the one end portion and the inner circumferential surface of the through hole is greater than 0.05 mm and less than 0.45 mm, There are a plurality of groups of two of the tooth portions adjacent to each other in the circumferential direction of the yoke portion, The two tooth portions in each group have at least a portion of the approach region on opposite sides of the two tooth portions.

14. The core according to claim 13, wherein: Coils of the same phase are arranged on the two teeth in each group.

15. The core according to claim 13, wherein: A ratio of a length of the proximity region along a circumferential direction of the through hole to a circumferential length of the through hole is greater than or equal to 20% and less than or equal to 70%.

16. The core according to claim 13, wherein: Each of the teeth has one end surface located inside the through hole and another end surface located outside the through hole. The yoke has a first surface located on the protruding side of each tooth portion, and a second surface opposite to the first surface. When a surface obtained by extending the second surface is defined as a reference surface and a length from the reference surface to the other end surface is defined as a height of each tooth portion, A fluctuation in height of the plurality of teeth is less than or equal to 0.1 mm.

17. The core according to claim 16, wherein: A length from the reference plane to the one end surface is less than or equal to 10% of a thickness of the yoke.

18. The core according to claim 13, wherein: The iron core is made of materials including pure iron, an iron-based alloy containing Si, or an iron-based alloy containing Al.

19. The core according to claim 13, wherein: The relative density of the iron core is greater than or equal to 90%.

20. A stator, comprising: The iron core according to any one of claims 1 to 19; and The coil is arranged on each of the teeth.

21. A rotating electrical machine, comprising: The stator of claim 20; and The rotor is arranged opposite to the stator.

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