阅读说明：本技术 铁芯、定子及旋转电机 (Iron core, stator and rotating electrical machine ) 是由 斋藤达哉 中村悠一 上野友之 于 2019-09-05 设计创作，主要内容包括：一种铁芯,其在轴向间隙型旋转电机中使用,该铁芯具有主体部和多个框状的凸缘部,所述主体部具有环状的轭部和在所述轭部的周向排列的多个柱状的齿部,各所述凸缘部固定于各所述齿部的前端部,所述轭部和多个所述齿部由一体的压粉成型体构成,各所述凸缘部由具有贯通孔的压粉成型体构成,所述齿部的前端部插入贯穿于所述贯通孔,所述齿部的端面从所述贯通孔露出,在所述轭部的轴向的俯视观察时,所述齿部的端面的面积相对于所述凸缘部的外周缘内的面积的比率大于或等于7.5％。(A core used in an axial gap type rotating electrical machine, the core having a body portion and a plurality of frame-shaped flange portions, the body portion having an annular yoke portion and a plurality of columnar teeth portions arranged in a circumferential direction of the yoke portion, each of the flange portions being fixed to a tip portion of each of the teeth portions, the yoke portion and the plurality of teeth portions being formed of an integral compact, each of the flange portions being formed of a compact having a through hole, the tip portion of the tooth portion being inserted through the through hole, end faces of the tooth portion being exposed from the through hole, a ratio of an area of the end face of the tooth portion to an area inside an outer peripheral edge of the flange portion being greater than or equal to 7.5% when viewed in plan in an axial direction of the yoke portion.)

1. An iron core used in an axial gap type rotating electrical machine,

the core has a main body portion and a plurality of frame-shaped flange portions,

the body portion has an annular yoke portion and a plurality of columnar teeth portions arranged in a circumferential direction of the yoke portion,

each of the flange portions is fixed to a tip end portion of each of the tooth portions,

the yoke and the plurality of teeth are formed of an integral powder compact,

each of the flange portions is formed of a powder compact having a through hole,

the tip end of the tooth portion is inserted into the through hole, and the end face of the tooth portion is exposed from the through hole,

a ratio of an area of an end surface of the tooth portion to an area inside an outer peripheral edge of the flange portion is 7.5% or more in a plan view in an axial direction of the yoke portion.

2. The core of claim 1,

the flange portion has an approach region in which a distance between an outer peripheral surface of the tip portion and an inner peripheral surface of the through hole is 0.05mm or less.

3. The core of claim 2,

the ratio of the length of the approach region in the circumferential direction of the through hole to the circumferential length of the through hole exceeds 20%.

4. The iron core of claim 2 or 3,

the difference between the maximum value and the minimum value of the distance between the outer peripheral surface of the tip portion and the inner peripheral surface of the through hole is less than 0.40 mm.

5. The iron core of any of claims 2 to 4,

the flange portion has at least a part of the approach area on an outer peripheral side of the yoke portion in the flange portion.

6. The iron core of any of claims 2 to 5,

the flange portion that is fixed to the tooth portions adjacent to each other in the circumferential direction of the yoke portion has at least a part of the approach region on the side opposite to the two tooth portions.

7. The core of claim 6,

coils of the same phase are arranged in adjacent teeth.

8. The iron core of any of claims 2 to 5,

the same side in the circumferential direction of the yoke in the flange portion has at least a part of the access region.

9. The iron core of any of claims 1-8,

the tooth portion has a stepped portion on which the flange portion is placed.

10. The core of claim 9,

the height of the stepped portion is greater than or equal to the thickness of the flange portion.

11. The core of claim 10,

the difference between the height of the step portion and the thickness of the flange portion exceeds 0mm and is less than or equal to 3 mm.

12. The iron core of any of claims 9 to 11,

the intersection angle of the bottom surface of the step portion and the peripheral surface of the step portion is 90 degrees,

an intersection angle between an inner peripheral surface of the through hole and a surface of the flange portion placed on a bottom surface of the stepped portion is 90 °.

13. The core of claim 11,

the tip of the tooth portion includes an inclined surface intersecting with an end surface of the tooth portion,

the angle of the inclined surface with respect to the extension surface of the end surface is greater than or equal to 5 DEG and less than or equal to 60 deg.

14. The iron core of any of claims 1-13,

the constituent material of the iron core includes: pure iron, an iron-based alloy containing Si, or an iron-based alloy containing Al.

15. The iron core of any of claims 1-14,

the relative density of the iron core is greater than or equal to 90%.

16. A stator, having:

the iron core of any one of claims 1 to 15; and

and a coil disposed in each of the teeth.

17. A rotating electrical machine having the stator of claim 16.

Technical Field

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

The present application claims priority based on japanese application No. 2018-212322 of 11/12/2018, and the entire contents of the disclosure in the above japanese application are cited.

Background

Patent document 1 discloses an axial gap type electric motor in which a rotor and a stator are disposed to face each other in an axial direction of the rotor as one of rotating electric machines. The stator used in such a rotating electrical machine has: a core having a yoke portion and a plurality of tooth portions; and a coil disposed in each tooth. Typically, the yoke is a circular plate-shaped member. Each tooth is a columnar member protruding in the axial direction of the yoke, and is arranged at a distance in the circumferential direction of the yoke. Patent document 1 also discloses that a plate-shaped flange portion is provided at an end portion of the tooth portion opposite to the end connected to the yoke portion.

Patent document 1: japanese laid-open patent publication No. 2009-044829

Disclosure of Invention

The iron core of the present invention is used in an axial gap type rotating electrical machine,

the core has a main body portion and a plurality of frame-shaped flange portions,

the body portion has an annular yoke portion and a plurality of columnar teeth portions arranged in a circumferential direction of the yoke portion,

each of the flange portions is fixed to a tip end portion of each of the tooth portions,

the yoke and the plurality of teeth are formed of an integral powder compact,

each of the flange portions is formed of a powder compact having a through hole,

the tip end of the tooth portion is inserted into the through hole, and the end face of the tooth portion is exposed from the through hole,

a ratio of an area of an end surface of the tooth portion to an area inside an outer peripheral edge of the flange portion is 7.5% or more in a plan view in an axial direction of the yoke portion.

The stator of the present invention comprises:

the iron core of the invention; and

and a coil disposed in each of the teeth.

The rotating electric machine of the present invention has the stator of the present invention.

Drawings

Fig. 1 is a schematic plan view showing an example of an iron core according to the embodiment.

Fig. 2 is a schematic perspective view showing a part of the core according to the embodiment.

Fig. 3 is a diagram illustrating a gap between an outer circumferential surface of a tip portion of a tooth portion and an inner circumferential surface of a through hole of a flange portion in a core according to an embodiment.

Fig. 4 is an example in which adjacent flange portions of the core according to the embodiment are provided so as to face the proximity region, and shows a schematic plan view of a part of the core.

Fig. 5 is an example in which adjacent flange portions of the core according to the embodiment have an adjacent region on the same side in the circumferential direction of the yoke portion, and shows a schematic plan view of a part of the core.

Fig. 6A is a partial cross-sectional view showing a part of a tooth portion having a step portion of the core according to the embodiment.

Fig. 6B is a partial cross-sectional view showing a part of a tooth portion having an inclined surface of the core according to the embodiment.

Fig. 7 is a schematic plan view showing an example of the stator according to the embodiment.

Fig. 8 is a schematic cross-sectional view showing an example of a rotating electric machine according to the embodiment.

Detailed Description

[ problems to be solved by the invention ]

It is desirable to construct a rotating electric machine that can easily assemble a stator and obtain high torque as a core used for an axial gap rotating electric machine.

Accordingly, an object of the present invention is to provide a core that can construct a rotating electric machine having high torque and is excellent in stator manufacturability.

Another object of the present invention is to provide a stator that can construct a rotating electric machine having a high torque and is excellent in manufacturability.

Another object of the present invention is to provide a rotating electric machine having high torque and excellent manufacturability.

[ Effect of the invention ]

The core of the present invention can construct a rotating electric machine having a high torque, and is excellent in the manufacturability of the stator.

The stator of the present invention can construct a rotating electric machine having a high torque and is excellent in manufacturability.

The rotating electric machine of the present invention has high torque and excellent manufacturability.

[ description of embodiments of the invention ]

First, embodiments of the present invention will be described.

(1) The iron core according to one aspect of the present invention is used in an axial gap type rotating electrical machine,

the core has a main body portion and a plurality of frame-shaped flange portions,

the body portion has an annular yoke portion and a plurality of columnar teeth portions arranged in a circumferential direction of the yoke portion,

each of the flange portions is fixed to a tip end portion of each of the tooth portions,

the yoke and the plurality of teeth are formed of an integral powder compact,

each of the flange portions is formed of a powder compact having a through hole,

the tip end of the tooth portion is inserted into the through hole, and the end face of the tooth portion is exposed from the through hole,

a ratio of an area of an end surface of the tooth portion to an area inside an outer peripheral edge of the flange portion is 7.5% or more in a plan view in an axial direction of the yoke portion.

The iron core of the present invention has a flange portion. Therefore, the core according to the present invention has the effect that the flange portion facilitates the passage of magnetic flux through the tooth portion and the flange portion facilitates the prevention of the coil from falling off, and the stator assembly workability is excellent. One of the reasons for the excellent assembly workability of the stator is that the core of the present invention is a combination having a main body portion and a flange portion, and the coils can be arranged in the respective tooth portions without the flange portion. Therefore, the core of the present invention can easily manufacture a stator and an axial gap type rotating electric machine.

As described below, the core of the present invention can suppress a decrease in torque and can construct an axial gap type rotating electrical machine having high torque.

Although the iron core of the present invention is an assembly as described above, the yoke portion and the tooth portion are an integral body. Therefore, a gap serving as a magnetic gap is not generated between the yoke and the tooth. The iron core of the present invention as described above allows magnetic flux to pass from the tooth portions through the yoke portion better than the iron core of patent document 1 in which the yoke portion and the tooth portions are separate members. In particular, the ratio of the area of the end face of the tooth portion of the iron core of the present invention to the area inside the outer peripheral edge of the flange portion is high and equal to or greater than 7.5%. Hereinafter, the ratio of the above area is sometimes referred to as an exposed area ratio. Since the exposed area ratio is high, the tooth portions exposed from the through holes of the flange portion receive magnetic flux directly, and the magnetic flux is easily caused to pass through the tooth portions from the flange portion. As a result, the reduction in torque is easily suppressed.

Further, the core of the present invention has the flange portion, but the increase of the cogging torque can be reduced. In the case of having the flange portions, the gap between the adjacent flange portions is generally narrow, and thus the cogging torque is likely to increase. However, the core of the present invention can utilize the gap generated between the inner peripheral surface of the flange portion and the outer peripheral surface of the tooth portion as a magnetic gap. Since the magnetic resistance can be increased by the gap, the change in magnetic flux caused by the rotation of the magnet can be easily reduced. Therefore, the increase in cogging torque is easily reduced.

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

an embodiment is given in which the flange portion has an approach region in which the distance between the outer peripheral surface of the distal end portion and the inner peripheral surface of the through hole is 0.05mm or less.

In the above aspect, the interval between the adjacent regions of the tooth portion and the flange portion is extremely narrow. Therefore, the region near the flange portion in the above-described aspect can be regarded as a region substantially in contact with the tooth portion. Further, it can be said that a gap which may be generated between the tooth portion and the approach region of the flange portion is less likely to become a magnetic gap. Therefore, the above-described aspect facilitates the magnetic flux to pass through the tooth portion from the vicinity region of the flange portion. Therefore, the above-described aspect makes it easier to suppress a decrease in torque, and enables construction of an axial gap type rotating electrical machine having high torque.

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

an embodiment is described in which the ratio of the length of the proximity region in the circumferential direction of the through hole to the circumferential length of the through hole exceeds 20%.

In the above aspect, the flange portion has a long proximity region, and therefore, it is easier to cause the magnetic flux to pass through the tooth portion from the proximity region of the flange portion. Therefore, the above-described aspect makes it easier to suppress a decrease in torque, and enables construction of an axial gap type rotating electrical machine having a higher torque.

(4) As an example of the iron core of the above (2) or (3),

an embodiment is described in which the difference between the maximum value and the minimum value of the distance between the outer peripheral surface of the tip portion and the inner peripheral surface of the through hole is less than 0.40 mm.

In the above-described embodiment, the magnetic gap may not have a portion where the gap is locally large, that is, a portion where the magnetic gap is large. Therefore, the above-described aspect facilitates the magnetic flux to pass through the tooth portions from the flange portion. Therefore, the above-described aspect makes it easy to suppress a decrease in torque, and enables construction of an axial gap type rotating electrical machine having high torque.

(5) As an example of any of the cores of the above-mentioned (2) to (4),

an embodiment is given in which the flange portion has at least a part of the proximity region on an outer peripheral edge side of the yoke portion in the flange portion.

The above-described method easily has a long proximity region as described below. The proximity region is long, and thus the magnetic flux can more easily pass through the tooth portion from the proximity region of the flange portion. Therefore, the above-described aspect makes it easier to suppress a decrease in torque, and enables construction of an axial gap type rotating electrical machine having a higher torque.

Typically, the outer shape of the flange portion is a trapezoidal shape. The length of the region of the flange portion having the above-described shape on the outer peripheral side of the yoke portion is longer than the length of the region on the inner peripheral side of the yoke portion. Hereinafter, a region of the flange portion located on the outer peripheral edge side of the yoke portion, that is, a region of the flange portion located on the outer peripheral side of the periphery of the end face of the tooth portion exposed from the through hole may be referred to as an outer peripheral region. In addition, a region of the flange portion located on the inner peripheral edge side of the yoke portion, that is, a region of the flange portion located on the inner peripheral side of the peripheral edge of the end face of the tooth portion exposed from the through hole may be referred to as an inner peripheral region. The core including the access region in the outer peripheral region of the flange portion easily secures the access region long.

(6) As an example of any of the cores of the above-mentioned (2) to (5),

the flange portion that is fixed to the tooth portions adjacent to each other in the circumferential direction of the yoke portion may have at least a part of the approach region on the side opposite to the two tooth portions.

In the above aspect, the adjacent flange portions are disposed so that their adjacent regions face each other. Therefore, the adjacent tooth portions easily pass the magnetic flux through the proximity region of each flange portion. Therefore, the above-described aspect makes it easy to suppress a decrease in torque, and enables construction of an axial gap type rotating electrical machine having high torque. In the case where the above-described aspect is applied to a multiphase ac rotating electrical machine, coils of the same phase or coils of different phases may be arranged in each tooth portion.

(7) As an example of the iron core of the above item (6),

an example is a mode in which coils of the same phase are arranged in the adjacent teeth.

In the above-described aspect, it is easier to suppress a decrease in torque than in the case where coils of different phases are arranged.

(8) As an example of any of the cores of the above-mentioned (2) to (5),

an embodiment is described in which at least a part of the proximity region is provided on the same side in the circumferential direction of the yoke in the flange portion.

In the above-described aspect, the magnetic flux easily passes through the tooth portions from the proximity region of each flange portion. Therefore, the above-described aspect makes it easy to suppress a decrease in torque, and enables construction of an axial gap type rotating electrical machine having high torque. In addition, in the above-described aspect, the fixed state of each flange portion can be made the same for each tooth portion, and therefore, the manufacturability of the core is also excellent.

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

an example is a mode in which the tooth portion has a stepped portion on which the flange portion is placed.

In the above aspect, the flange portion can be stably arranged with respect to the tooth portion, and the tooth portion and the flange portion can be easily fixed. Therefore, the above-described embodiment is also excellent in the manufacturability of the core.

(10) As an example of the iron core of the above item (9),

an embodiment is given in which the height of the stepped portion is greater than or equal to the thickness of the flange portion.

In the above aspect, if the height of the step portion and the thickness of the flange portion are equal to each other, the end surfaces of the tooth portion and the flange portion are typically coplanar with each other. Therefore, the gap between the stator and the rotor having the core of the above-described embodiment can be easily adjusted. In the above aspect, the larger the height of the step portion is compared to the thickness of the flange portion, the easier the cogging torque is to be reduced.

(11) As an example of the iron core of the above (10),

an embodiment is described in which the difference between the height of the stepped portion and the thickness of the flange portion exceeds 0mm and is less than or equal to 3 mm.

Since the difference in the above-described aspect satisfies the above-described specific range, cogging torque can be reduced and a decrease in torque can be suppressed.

(12) As an example of any of the cores of the above (9) to (11),

the cross angle between the bottom surface of the stepped portion and the peripheral surface of the stepped portion is 90 DEG,

and a mode in which an intersection angle between an inner peripheral surface of the through hole and a surface of the flange portion placed on a bottom surface of the stepped portion is 90 °.

The stepped portion and the flange portion in the above embodiment are simple in shape and easy to mold. Therefore, the above-described embodiment is also excellent in the manufacturability of the core.

(13) As an example of the iron core of the above (11),

the tip end of the tooth portion includes an inclined surface intersecting with an end surface of the tooth portion,

an angle of the inclined surface with respect to an extension surface of the end surface is greater than or equal to 5 ° and less than or equal to 60 °.

In the above aspect, when the inclined surfaces of the tooth portions project from the end surfaces of the flange portions, the cogging torque is easily reduced.

(14) As an example of the iron core of the present invention,

the constituent material of the iron core includes: pure iron, an iron-based alloy containing Si, or an iron-based alloy containing Al.

When pure iron is included in the above-described embodiment, the iron core easily has a high saturation magnetic flux density, the iron core easily becomes dense, the iron core is easily molded, and the manufacturability is excellent. When the iron-based alloy is included in the above embodiment, the iron core tends to have a low loss.

(15) As an example of the iron core of the present invention,

an embodiment in which the relative density of the iron core is 90% or more is given.

The above mode is highly dense with a relative density of 90% or more. As described above, an axial gap type rotating electrical machine having excellent magnetic characteristics, such as high saturation magnetic flux density, can be constructed.

(16) A stator according to an embodiment of the present invention includes:

any one of the iron cores of (1) to (15) above; and

and a coil disposed in each of the teeth.

Since the stator of the present invention includes the core of the present invention, coils can be easily arranged in the teeth. Therefore, the stator of the present invention is excellent in manufacturability. Further, since the stator of the present invention includes the core of the present invention, it is possible to suppress a decrease in torque and construct an axial gap type rotating electrical machine having high torque.

(17) A rotating electrical machine according to an embodiment of the present invention includes the stator of the present invention.

Since the rotating electric machine of the present invention includes the stator of the present invention, the stator can be easily assembled, and the manufacturing efficiency is excellent. Further, since the rotating electric machine according to the present invention includes the stator according to the present invention, it is possible to suppress a decrease in torque and to obtain high torque.

[ details of embodiments of the present invention ]

Embodiments of the present invention will be specifically described below with reference to the drawings. The same reference numerals in the drawings denote the same items.

[ iron core ]

The core 1 of the embodiment will be described with reference to fig. 1 to 6B.

Fig. 1, 4, 5, and 7 described later are plan views of the core 1 according to the embodiment as viewed from the axial direction of the yoke 3 in plan view. The above figures show the surface of the yoke 3 on the tooth 2 side, and the surface 30 is seen in plan view. Fig. 4 and 5 show only a part of the core 1.

Fig. 2 is a perspective view showing a part of the core 1 according to the embodiment, and shows a state before the teeth 2 and the flange 5 are disassembled and the flange 5 is fixed to the teeth 2 with respect to a set of the teeth 2 and the flange 5.

Fig. 3 is a plan view of a pair of the tooth portion 2 and the flange portion 5, as viewed from above from the side of the end face 20 of the tooth portion 2 and the end face 50 of the flange portion 5 in the axial direction of the tooth portion 2.

Fig. 6A and 6B are cross-sectional views of the core 1 according to the embodiment cut along a plane parallel to the axial direction of the tooth 2, and only the tip of the tooth 2 and its vicinity, and the flange 5 are shown. The sectional views of fig. 6A and 6B correspond to the sectional views obtained by cutting the core 1 along the VI-VI cutting line shown in fig. 2.

For convenience of explanation, the scale of fig. 1 to 6B and fig. 7 and 8 described later are appropriately changed.

Summary of the invention

Next, the outline of the core 1 will be described mainly with reference to fig. 1 and 2.

The core 1 of the embodiment includes an annular yoke portion 3, a plurality of columnar teeth portions 2, and a plurality of plate-like flange portions 5. Each flange 5 is provided at the tip of each tooth 2. The iron core 1 is used in an axial gap type rotating electrical machine. As a typical example, the core 1 can be used as a stator core. An example of the axial gap type rotating electrical machine is a rotating electrical machine 9 shown in fig. 8 described later. An example of the stator is a stator 8 shown in fig. 7 described later. The core 1 has coils 80 (fig. 7 and 8) disposed in the teeth 2 and is used as a component of a magnetic path through which magnetic flux generated by the coils 80 and magnetic flux of the magnets 95 (fig. 8) pass.

In the core 1 of the embodiment, the yoke portion 3 and the plurality of tooth portions 2 are integrated, and each flange portion 5 is a member independent of the integrated object. Each flange 5 is a frame-shaped member having a through hole 52. The end faces 20 of the tooth portions 2 are exposed from the through holes 52. In particular, in the core 1 of the embodiment, the ratio of the area of the end face 20 of the tooth 2 to the area inside the outer peripheral edge 51 of the flange 5, that is, the exposed area ratio is 7.5% or more in a plan view in the axial direction of the yoke 3.

The following describes the details.

Main body part

The core 1 of the embodiment has the body 4 as one of the constituent members. The body portion 4 has a yoke portion 3 and a plurality of tooth portions 2 arranged in the circumferential direction of the yoke portion 3. The body portion 4 is formed of a powder compact in which the yoke portion 3 and the plurality of tooth portions 2 are integrated. The core 1 is an assembly of 1 body portion 4 and a plurality of flange portions 5, but the yoke portion 3 and the tooth portion 2 are integrated. Therefore, a gap serving as a magnetic gap is not generated between the yoke 3 and the tooth 2. Therefore, the core 1 allows magnetic flux to pass from the tooth portion 2 to the yoke portion 3 more favorably than a core in which the yoke portion 3 and the tooth portion 2 are separate members.

Yoke portion

The yoke 3 is a plate member having an annular planar shape. One of the front and back surfaces of the yoke 3, here the surface 30, is a surface on which the teeth 2 are provided to protrude. The yoke 3 magnetically couples adjacent teeth 2 to each other among the teeth 2 arranged in the circumferential direction of the yoke 3. The yoke 3 has a shaft hole 39 in the center thereof. The shaft hole 39 penetrates the front and back surfaces of the yoke 3.

Tooth section

Each tooth 2 is a columnar member, and protrudes so as to be orthogonal to the surface 30 of the yoke 3. The teeth 2 are arranged at predetermined intervals in the circumferential direction of the yoke 3. Typically, as illustrated in fig. 1, the teeth 2 are arranged at equal intervals in the circumferential direction of the yoke 3. The direction orthogonal to the surface 30 of the yoke 3 corresponds to the direction parallel to the axial direction of the shaft hole 39 of the yoke 3. The axial direction of each tooth 2 corresponds to a direction parallel to the axial direction of the yoke 3. In fig. 1, the axial direction of the yoke 3 corresponds to a direction perpendicular to the paper surface.

Typically, the teeth 2 have the same shape and size.

The outline of the tooth portion 2 is typically a prismatic shape having a cross-sectional shape cut by a plane orthogonal to the axial direction of the tooth portion 2 and having the same shape in the axial direction of the tooth portion 2. The tooth portion 2 of this example is a quadrangular prism having a trapezoidal cross-sectional shape. The tooth portion 2 of this example has the same cross-sectional shape in the axial direction of the tooth portion 2 except for the tip end portion that fixes the flange portion 5. The tooth 2 having a trapezoidal cross-sectional shape can easily secure a large cross-sectional area. In addition, the dead space of the core 1 is easily reduced. As a result, the stator 8 with a high space factor can be easily constructed. Examples of the other external shape include a prism having a triangular cross-sectional shape such as an isosceles triangle. In addition, other external shapes include a rectangular parallelepiped having a rectangular cross-sectional shape and a circular cylindrical cross-sectional shape.

The "trapezoidal shape" and the "triangular shape" herein include not only a geometrically trapezoidal shape and a geometrically triangular shape but also a shape having a chamfer at a corner portion as in this example, and include a range that can be substantially regarded as a trapezoidal shape and a triangular shape. For example, when the outline of the cross section includes a straight line, the intersection of the extension lines of the straight line included in the above range forms the shape of the vertex of the polygon. Alternatively, for example, when the outline of the cross section includes a curve and a straight line, the above range includes a shape in which the intersection of the tangent to the curve and the straight line or the extension line of the straight line forms the vertex of the polygon.

The number of the teeth 2 may be appropriately selected as long as it is 2 or more. The number may be, for example, greater than or equal to 3, or even greater than or equal to 6. Fig. 1 illustrates the main body 4 having the above-described number of 12.

Each flange portion 5 is fixed to a tip end portion of each tooth portion 2 located on the opposite side of the end connected to the yoke portion 3. That is, one end of each tooth 2 constitutes a connection portion with the yoke 3. The other end of each tooth 2 constitutes a fixing site of the flange 5. In a state where the flange portion 5 is fixed, the end faces 20 of the tooth portions 2 are exposed from the flange portion 5. Fig. 1 and fig. 7 described later are cross-hatched at the end face 20 for easy understanding.

The shape of the end surface 20 is similar to the shape of the circumferential surface 21 (fig. 2) of the tooth 2 except for the tip end portion, or is substantially similar to the shape in this example. Hereinafter, the portion of the tooth 2 other than the tip portion is referred to as an intermediate portion. If the rotating electrical machine 9 is constructed using the iron core 1 as described above, the magnetic flux of the magnet 95 easily passes through the end face 20 at any position in the circumferential direction of the tooth 2. As a representative example, the end face 20 is formed of a plane parallel to the surface 30 of the yoke 3 as in this example, and is arranged so as to be orthogonal to the magnetic flux. In addition, as a representative case, the circumferential surface 21 is provided so as to be orthogonal to the surface 30 of the yoke 3 as in this example.

In addition, the shape of the end surface 20 may be different from the shape of the peripheral surface 21 of the intermediate portion of the tooth 2. For example, if the shape of the circumferential surface 21 of the intermediate portion in the tooth portion 2 is a trapezoidal shape, the shape of the end surface 20 may be a circle, a triangle, or the like. However, from the viewpoint of passing magnetic flux, the shape of the end face 20 is preferably similar or substantially similar to the shape of the circumferential surface 21 as described above.

The tooth 2 may have a step 25 (fig. 2) at the tip end. The flange portion 5 is placed on the step portion 25. Details of the tip end of the tooth 2, including the size of the end face 20, the shape of the stepped portion 25, and the like, will be described in the section "relationship between the tooth and the flange portion".

"size

The size of the yoke 3 and the size of the tooth 2 can be appropriately selected according to the rotating electrical machine 9.

The size of the yoke 3 includes, for example, an outer diameter, an inner diameter, and a thickness. The outer diameter of the yoke 3 is, for example, 30mm or more and 300mm or less. The inner diameter of the yoke 3, in this case, the diameter of the shaft hole 39, is, for example, 5mm or more and 150mm or less. The thickness of the yoke 3 is, for example, 1.0mm or more and 10mm or less, and more specifically 1.5mm or more and 7.0mm or less.

The size of the tooth 2 includes, for example, a cross-sectional area and a height. The cross-sectional area of the tooth 2 here is the area of a cross-section cut by a plane orthogonal to the axial direction of the tooth 2. When the tooth 2 has the stepped portion 25, it is a cross-sectional area of an intermediate portion other than the tip end portion. The height of the tooth 2 is the distance from the surface 30 of the yoke 3 to the end face 20. The cross-sectional area of the tooth 2 is, for example, 5mm or more²And less than or equal to 800mm². The height of the tooth 2 is, for example, 3mm or more and 40mm or less.

Flange part

Each flange 5 is a frame-shaped plate member fixed to the tip end of each tooth 2. Each flange 5 is formed of a powder compact having a through hole 52. The tip end portion of each tooth 2 is inserted into each through hole 52. Typically, the flange portions 5 have the same shape and size.

Function and action

As described below, the flange portion 5 has a function of passing more magnetic flux than the tooth portion 2. In a state of being fixed to the tip end portion of the tooth portion 2, the flange portion 5 projects from the circumferential surface 21 of the tooth portion 2 in a direction orthogonal to the circumferential surface 21. Therefore, the planar area of the tip end of the tooth 2 to which the flange 5 is fixed is the total area of the end face 20 and the end face 50 of the flange 5. Therefore, the area of the flat surface of the tip of the tooth 2 to which the flange 5 is fixed is larger than the cross-sectional area of the middle portion of the tooth 2 by the flange 5. If the rotating electrical machine 9 is constructed using the core 1 as described above, the area of the core 1 facing the magnet 95 is larger than that without the flange portion. Therefore, the iron core 1 easily concentrates the magnetic flux of the magnet 95 on the tooth portions 2 through the flange portions 5, and more of the magnetic flux easily passes through.

The core 1 has the flange portion 5, but as described below, the stator 8 and the rotating electrical machine 9 are excellent in manufacturability. The core 1 is a separable assembly of a main body portion 4 having the tooth portions 2 and a flange portion 5. Therefore, in the manufacturing process of the stator 8 and the rotating electric machine 9, the coil 80 can be disposed in the tooth portion 2 in a state where the flange portion 5 is not disposed at the tip of the tooth portion 2. Therefore, the assembly work of the core 1 and the coil 80 is easy. The tooth portion 2 on which the coil 80 is arranged and the flange portion 5 are integrated. For example, the tip end portion of the tooth portion 2 is inserted into the through hole 52 penetrating the flange portion 5, and the tooth portion 2 and the flange portion 5 are joined by an adhesive or the like, or fixed by press fitting, shrink fitting, or the like. In the hot press fitting, for example, the flange portion 5 can be heated to an appropriate temperature. By fixing the tooth portion 2 and the flange portion 5 in the above manner, the body portion 4 and the flange portion 5 are integrated.

In addition, the flange portion 5 has a function of preventing the coil 80 from falling off from the tooth portion 2, and the like. Further, although the core 1 has the flange portion 5, the increase in cogging torque can be reduced as described below. Although there is a possibility that a gap may be generated between the outer peripheral surface of the tip end portion of the tooth portion 2 and the inner peripheral surface 520 (fig. 2) of the flange portion 5 forming the through hole 52, the core 1 can utilize the gap as a magnetic gap. Due to this magnetic gap, the magnetic resistance between the flange portion 5 and the tooth portion 2 increases. If the rotating electrical machine 9 is constructed using the iron core 1 as described above, it is easy to reduce the variation in magnetic flux accompanying the rotation of the magnet 95. In addition, the figures show the above gap as large for ease of understanding.

"shape

The outer peripheral shape of the flange portion 5, i.e., the shape described by the outer peripheral edge 51, is similar to the shape of the peripheral surface 21 of the middle portion of the tooth portion 2, or is substantially similar to the shape in this example. In this case, the flange portion 5 preferably allows the magnetic flux of the magnet 95 to easily pass through at any position in the circumferential direction of the tooth portion 2.

The inner peripheral shape of the flange portion 5, that is, the shape drawn by the inner peripheral surface 520 of the through hole 52 is similar to the outer peripheral shape of the flange portion 5 as shown in this example. In this case, the gap between the outer peripheral edge 51 and the inner peripheral surface 520 of the flange portion 5, i.e., the width, is easily uniform in the circumferential direction of the flange portion 5. Therefore, the effect of allowing the magnetic flux of the magnet 95 to easily pass through the flange portion 5 at any position in the circumferential direction of the tooth portion 2 can be easily and uniformly obtained. The inner peripheral shape of the flange portion 5 may be a shape that is not similar to the outer peripheral shape of the flange portion 5, but from the viewpoint of magnetic flux passage, a shape that is similar to the above or a shape that is substantially similar is preferable.

As an example of the inner peripheral shape of the flange portion 5, the shape is similar to the shape of the end surface 20 of the tooth portion 2. In this case, it is easy to prevent a gap generated between the inner peripheral surface 520 of the flange portion 5 and the outer peripheral surface of the tip end portion of the tooth portion 2 from being locally increased. A locally large gap becomes a large magnetic gap. If a large magnetic gap exists between the inner peripheral surface 520 of the flange portion 5 and the outer peripheral surface of the tip end portion of the tooth portion 2, a decrease in torque occurs. By reducing the large magnetic gap, a decrease in torque is suppressed.

The outer peripheral shape and the inner peripheral shape of the flange portion 5 of this example are trapezoidal shapes with rounded corners. In a state where the flange portion 5 is fixed to the tooth portion 2, a long side portion of a trapezoid in the contour of the flange portion 5 is disposed on the outer peripheral edge side of the yoke portion 3. The short side portion of the trapezoid is disposed on the inner peripheral side of the yoke 3. In addition, as a representative case, the end surface 50 and the surface opposite thereto are constituted by flat surfaces as in this example.

Relationship between tooth portion and flange portion

Next, the tip of the tooth 2 and the through hole 52 of the flange 5 will be described in detail mainly with reference to fig. 3 to 6B.

Area ratio of exposure

In the core 1 of the embodiment, a part of the tooth portion 2, specifically, the end face 20 of the tip portion is exposed from the through hole 52 of the flange portion 5. Therefore, the magnetic gap arranged in the direction orthogonal to the magnetic flux between the flange portion 5 and the tooth portion 2 is easily reduced. Hereinafter, this magnetic gap is referred to as an orthogonal gap. In the core 1, the size of the orthogonal gap is smaller than the cross-sectional area of the middle portion of the tooth 2. In some cases, the core 1 does not substantially have the orthogonal gap. Since the orthogonal gap of the core 1 is small, the magnetic flux of the magnet 95 (fig. 8) easily passes through the tooth 2 from the flange 5. Therefore, although the tooth portion 2 and the flange portion 5 of the core 1 are independent members, a decrease in torque due to a magnetic gap generated therebetween can be suppressed. For example, sample Nos. 101 and 1 of test example 1 described later may be compared with each other.

Quantitatively, the area S of the end face 20 of the tooth 2 exposed from the through hole 52₂Relative to the area S in the outer peripheral edge 51 of the flange portion 5₅The ratio of (3), i.e., the exposed area ratio, is 7.5% or more. The exposed area ratio (%) is calculated by (S)₂/S₅) X 100. Further, the area S in the flange portion 5 described above₅But also the area of the through-hole 52.

If the above-mentioned exposed area ratio is 7.5% or more, the end faces 20 of the teeth 2 directly receive the magnetic flux of the magnet 95. In addition, if the exposed area ratio is 7.5% or more, the orthogonal gap is easily reduced. Therefore, the magnetic flux of the magnet 95 easily passes through the tooth 2 from the flange 5. Therefore, the iron core 1 easily suppresses a decrease in torque, and the rotating electrical machine 9 having high torque can be constructed.

As the exposed area ratio is higher, the decrease in torque is more easily suppressed. When it is desired to further suppress the decrease in torque, the exposed area ratio is preferably 8.0% or more, more preferably 10% or more. This is achieved by referring to test example 2 described later.

If the above-mentioned exposed area ratio is, for example, 90% or less, the width of the flange portion 5 can be secured to a certain extent to be large. Therefore, the effect of increasing the magnetic flux passing through the flange portion 5, the anti-separation effect of the coil 80, and the like can be easily obtained. Further, if the width of the flange portion 5 is large to some extent, the flange portion 5 can be easily molded, the flange portion 5 is excellent in manufacturability, the flange portion 5 can be easily handled, and the tooth portion 2 and the flange portion 5 can be easily assembled. In the case where the above effects are desired, the exposed area ratio may be 80% or less, or more specifically 70% or less, 60% or less, or less than 60%.

Gap between approach region and tooth portion

The size of the through hole 52 of the flange portion 5 is typically designed to be larger than the size of the tip end portion of the tooth portion 2 so as to facilitate the insertion and penetration operation of the tooth portion 2. As a result, a gap is formed between the outer peripheral surface of the tip end of the tooth 2 and the inner peripheral surface 520 of the through hole 52. This gap becomes a magnetic gap, which causes a reduction in torque. On the other hand, the present inventors have found that if the above-described portion having a very small gap is present in at least a part of the circumferential direction of the through hole 52, a decrease in torque can be suppressed. The reason for this is considered to be that the magnetic flux of the magnet 95 easily passes through the tooth portions 2 from the region of the flange portion 5 where the gap is narrow. Therefore, the flange portion 5 preferably has a region in which the distance between the outer peripheral surface of the tip end portion of the tooth portion 2 and the inner peripheral surface 520 of the through hole 52 of the flange portion 5 is less than or equal to 0.05 mm. The distance between the outer peripheral surface of the tip end portion of the tooth portion 2 and the inner peripheral surface 520 of the through hole 52 of the flange portion 5 is the shortest distance among the distances of straight lines connecting a point on the outer peripheral surface of the tip end portion of the tooth portion 2 and a point on the inner peripheral surface 520 of the through hole 52 of the flange portion 5. Hereinafter, a region of the flange portion 5 satisfying the above-described interval of 0.05mm or less is referred to as an approach region 55. Fig. 3 to 5 are cross-hatching lines in which two-dot chain lines are drawn on a part of the region near the inner peripheral surface 520 of the through-hole 52, and virtually show the approach region 55.

The distance between the tip of the tooth 2 and the proximal region 55 of the flange 5 is extremely narrow, not more than 0.05 mm. The proximity region 55 of the flange portion 5 as described above can be said to substantially contact the tip end of the tooth portion 2. Further, if the distance between the tip of the tooth 2 and the proximity region 55 of the flange 5 is less than or equal to 0.05mm, it can be said that the gap between the tip of the tooth 2 and the proximity region 55 of the flange 5 is less likely to become a magnetic gap. If the rotating electrical machine 9 is constructed using the iron core 1 as described above, the proximity region 55 of the flange portion 5 easily passes the magnetic flux of the magnet 95 through the tooth portion 2. Therefore, the rotating electrical machine 9 can more easily suppress a decrease in torque and can easily have a high torque.

The smaller the distance between the tip of the tooth 2 and the proximity region 55 of the flange 5, the more easily the proximity region 55 allows the magnetic flux of the magnet 95 to pass through the tooth 2, and the more easily the torque is suppressed from decreasing. When it is desired to further suppress the decrease in torque, the interval is preferably 0.04mm or less, more preferably 0.03mm or less and 0.02mm or less. The core 1 may have the portion where the interval is substantially 0 mm. For example, if press fitting or the like is used to fix the teeth 2 and the flange 5, the flange 5 can easily secure the portion having the interval of 0mm long.

Bonding ratio

The proximity region 55 of the flange portion 5 is preferably as long as possible. Quantitatively, the length L of the proximity region 55 in the circumferential direction of the through-hole 52 is mentioned₅₅The circumferential length L of the through hole 52 with respect to the flange portion 5₅The ratio of (A) exceeds 20%. Next, the length L is set₅₅Relative to the above-mentioned perimeter L₅The ratio of (b) is referred to as a bonding ratio. The above joining ratio (%) is obtained by (L)₅₅/L₅) X 100.

If the above-mentioned joining ratio exceeds 20%, the proximity region 55 of the flange portion 5 can be said to be long. Therefore, the magnetic flux of the magnet 95 easily passes through the tooth 2 by the proximity region 55. As a result, the decrease in torque is more easily suppressed. In the case where it is desired to further suppress the decrease in torque, the engagement ratio is preferably 25% or more, more preferably 30% or more, and 35% or more.

The larger the above-mentioned bonding ratio is in the range of 100% or less, the better. On the other hand, if the joining ratio is, for example, 70% or less, the margin in the insertion penetration work can be secured large. As a result, the assembling work of the tooth portion 2 and the flange portion 5 is facilitated. When it is desired to improve the assembling workability, the joining ratio may be 65% or less, or may be 60%.

Maximum difference in Interval

Since the flange portion 5 has the proximity region 55, a portion may be formed where the distance between the outer peripheral surface of the tip end portion of the tooth portion 2 and the inner peripheral surface 520 of the through hole 52 of the flange portion 5 is relatively large. In this case, too, the difference between the maximum value and the minimum value of the interval is preferably less than 0.40 mm. Hereinafter, this difference is referred to as a maximum difference of the intervals. Fig. 3 illustrates a case where the minimum value g of the interval is the minimum value_minThe maximum value g of the interval is located at a position in the inner peripheral surface 520 of the flange 5 which is located close to the region 55_maxThe inner peripheral surface 520 of the flange 5 is positioned on the inner peripheral edge side of the yoke 3 and is positioned at a lower corner in fig. 3. Fig. 3 illustrates a case where a part of the proximity region 55 is located on the outer peripheral edge side of the yoke portion 3 in the inner peripheral surface 520 of the flange portion 5, and is located on the upper side in fig. 3.

If the maximum difference in the above-described intervals is less than 0.40mm, the core 1 may not have a portion where the interval between the outer peripheral surface of the tip portion of the tooth portion 2 and the inner peripheral surface 520 of the through hole 52 of the flange portion 5 is locally large. The portion where the gap is locally large becomes a large magnetic gap. Therefore, if the maximum difference in the above-described intervals is less than 0.40mm, the core 1 does not have a large magnetic gap, and the magnetic flux of the magnet 95 easily passes through the tooth portion 2 from the flange portion 5. Therefore, the decrease in torque is easily suppressed. As the maximum difference in the above-described intervals is smaller, the core 1 does not have a large magnetic gap more clearly, and the magnetic flux is easily caused to pass through the teeth 2, so that the decrease in torque is more easily suppressed. In the case where it is desired to further suppress the decrease in torque, the maximum difference in the above-described intervals is preferably 0.35mm or less, more preferably 0.30mm or less.

The maximum difference in the above intervals may be 0 mm. In this case, it can be said that the interval between the outer peripheral surface of the tip end portion of the tooth portion 2 and the inner peripheral surface 520 of the through hole 52 of the flange portion 5 is uniform in the circumferential direction of the through hole 52. In the case where the interval is uniform, if the interval is 0.20mm or less, further 0.15mm or less, or 0.10mm or less, the magnetic flux of the magnet 95 can easily pass through the tooth portions 2 from the flange portions 5 even if the flange portions 5 do not have the proximity regions 55 in the core 1. Therefore, the decrease in torque is easily suppressed. This point can be obtained by referring to test example 1 described later.

Preferably, the flange portion 5 has an access area 55 and the maximum difference in the above-mentioned spacing is less than 0.40 mm. The reason for this is that the magnetic flux of the magnet 95 is easily caused to pass through the tooth portion 2 by the proximity region 55, and the flange portion 5 is present in proximity to the outer peripheral surface of the tip end portion of the tooth portion 2 in a region other than the proximity region 55. Therefore, magnetic flux can be more easily caused to pass through the tooth portions 2 from the flange portion 5, and a decrease in torque can be more easily suppressed. This is achieved by referring to test example 3 described later.

Location of approach area

The flange portion 5 has an approach region 55 at an arbitrary position in the circumferential direction of the through hole 52. As illustrated in fig. 3, the flange portion 5 includes at least a part of the proximity region 55 on the outer peripheral edge side of the yoke portion 3 in the flange portion 5. In this case, the proximity region 55 is easily set long. For example, if the inner peripheral shape of the flange portion 5 is a trapezoidal shape or the like, and if the longer side portion of the trapezoid is located on the outer peripheral side of the yoke portion 3, the length of the outer peripheral region 56 of the flange portion 5 located on the outer peripheral side of the yoke portion 3 is longer than the length of the inner peripheral region 57 of the flange portion 5 located on the inner peripheral side of the yoke portion 3. Therefore, if at least a part of the access region 55 is provided in the outer peripheral region 56 of the flange portion 5, the access region 55 is easily secured long. The longer the proximity region 55 is, the larger the above-mentioned joining ratio is. As a result, the core 1 can more easily pass the magnetic flux from the proximity region 55 through the tooth 2, and can more easily suppress a decrease in torque.

Fig. 3 illustrates a case where the proximity region 55 is formed in an L shape over the outer peripheral region 56 of the flange portion 5 and the region on one side of the flange portion 5 in the circumferential direction of the yoke portion 3. Alternatively, the core 1 may have the proximity region 55 only in the outer peripheral region 56 of the flange portion 5. Alternatively, the core 1 may have the proximity region 55 only in the inner peripheral region 57 of the flange portion 5 or in a region on one side of the flange portion 5 in the circumferential direction of the yoke portion 3.

Preferably, the flange portion 5 has at least a part of the approach area 55 in the outer peripheral area 56 of the flange portion 5, and the above-mentioned joining ratio is 35% or more. The reason for this is that the magnetic flux of the magnet 95 is more likely to pass through the tooth portion 2 by the approach region 55, and the decrease in torque is more likely to be suppressed. The bonding ratio can be determined by referring to test example 4 described later.

Alternatively, as illustrated in fig. 4, a flange portion 5 that is fixed to tooth portions 2 adjacent to each other in the circumferential direction of the yoke portion 3 may have at least a part of the approach region 55 on the side opposite to the two tooth portions 2. In this case, the adjacent flange portions 5 face the adjacent regions 55. Therefore, magnetic flux easily passes through the adjacent tooth portions 2 from the proximity region 55 of each flange portion 5, and a decrease in torque is easily suppressed.

When the iron core 1 having the adjacent flange portions 5 facing each other and the proximity region 55 is used in the multiphase ac rotating electrical machine, the coils 80 of the same phase or the coils 80 of different phases are arranged in the adjacent tooth portions 2. In particular, if coils 80 of the same phase are arranged in adjacent teeth 2, it is easier to suppress a decrease in torque than in the case where coils 80 of different phases are arranged. This point can be obtained by referring to test example 5 described later.

For example, when the core 1 is used in a three-phase ac rotating electrical machine, the following arrangement is given. Coils 80 of the U-phase are arranged in the 1 st tooth 2 and the 2 nd tooth 2 from the left side in fig. 4. In the 3 rd tooth 2 and the 4 th tooth 2, not shown, V-phase coils are arranged from the left side in fig. 4. In the 5 th tooth 2 and the 6 th tooth 2 not shown, W-phase coils not shown are arranged from the left side of fig. 4. In this case, the approaching region 55 is disposed on the side where the two teeth 2 are distant from each other in the teeth 2 in which the coils 80 of different phases are disposed in the adjacent teeth 2, for example, the 2 nd tooth 2 and the 3 rd tooth 2 from the left side in fig. 4. Fig. 4 virtually shows a state where the coil 80 is disposed in the 2 tooth portions 2 on the left side of the paper surface by a two-dot chain line. This point is also the same as in fig. 5 described later.

Alternatively, as illustrated in fig. 5, the flange portion 5 may have at least a part of the proximity region 55 on the same side in the circumferential direction of the yoke portion 3 in the flange portion 5. In this case, magnetic flux easily passes through each tooth 2 from the proximity region 55 of each flange 5, and a decrease in torque is easily suppressed. In this case, the state of the magnetic flux passing from each flange 5 to each tooth 2 is easily uniform, the magnetic flux is not easily disturbed, and the pulsation of the torque is easily reduced. In this case, the fixed state of each flange 5 is easily the same for each tooth 2. The iron core 1 is also excellent in manufacturability in this point. Fig. 5 illustrates a case where a part of the proximity region 55 is provided on the right side of the through hole 52 of each flange 5.

In the case where the rotating electrical machine 9 is constructed using the core 1 having the proximity region 55 of each flange portion 5 on the same side in the circumferential direction of the yoke portion 3, each flange portion 5 may have the proximity region 55 on any one of the same side as the rotation direction of the rotor 90 (fig. 9) and the opposite side to the rotation direction. In particular, if each flange portion 5 has the proximity region 55 on the same side as the above-described rotation direction, it is easier to suppress a decrease in torque than in the case of having it on the opposite side. This point can be obtained by referring to test example 5 described later.

Step section

Next, the step portion 25 will be described mainly with reference to fig. 6A.

If the tooth portion 2 has the step portion 25 at the tip end portion, the flange portion 5 is stably arranged with respect to the tooth portion 2 in the manufacturing process of the core 1. Therefore, in the core 1 having the step portion 25, the tooth portion 2 and the flange portion 5 are easily fixed by an adhesive or the like, or the flange portion 5 is easily arranged at a predetermined position of the tooth portion 2 at the time of press-fitting or hot press-fitting, compared with the case without the step portion 25, and the manufacturability is excellent.

The step portion 25 has a bottom surface 250 and a peripheral surface 251. Typically, the bottom surface 250 is a flat surface parallel to the end surface 20 (see also fig. 2), and a surface of the flange portion 5 opposite to the end surface 50 is placed thereon. The circumferential surface 251 is typically formed of a surface parallel to the circumferential surface 21 of the tooth 2. In the step portion 25 described above, the intersection angle between the bottom surface 250 and the peripheral surface 251 is 90 °. In addition, in correspondence with the stepped portion 25, the intersection angle between the inner peripheral surface 520 of the through hole 52 of the flange portion 5 and the surface of the flange portion 5 placed on the bottom surface 250 of the stepped portion 25 of the tooth portion 2 is 90 °. In this case, the shape of the step portion 25 and the shape of the flange portion 5 are simple, and the tooth portion 2 and the flange portion 5 can be easily formed with high accuracy. Therefore, the iron core 1 is excellent in manufacturability.

The height h of the step portion 25 is set to be the distance between the end surface 20 of the tooth portion 2 and the bottom surface 250. The thickness t of the flange portion 5 is defined as the distance between the end surface 50 of the flange portion 5 and the surface opposite thereto. For example, the height h of the stepped portion 25 is equal to the thickness t of the flange portion 5. In this case, the angle of intersection between the end surface 20 of the tooth 2 and the peripheral surface 251 of the step portion 25 is typically 90 °. In this case, as illustrated in fig. 2, in a state where the tooth portions 2 and the flange portions 5 are fixed, the end surfaces 20 of the tooth portions 2 and the end surfaces 50 of the flange portions 5 are flush with each other. When the stator 8 and the rotating electric machine 9 are constructed using the core 1, the gap between the stator 8 and the rotor 90 can be easily adjusted.

Alternatively, for example, the height h of the step portion 25 is larger than the thickness t of the flange portion 5. In this case, as illustrated in fig. 6A, in a state where the tooth portions 2 and the flange portion 5 are fixed, the end surfaces 20 of the tooth portions 2 and the vicinity thereof protrude from the end surface 50 of the flange portion 5. When a part of the tooth portion 2 protrudes from the flange portion 5 as described above, the tooth portion 2 is more likely to reduce the cogging torque as the protrusion height of the tooth portion 2 is larger, that is, the height h is larger and the difference Δ (h-t) between the height h and the thickness t is larger. However, if the difference Δ (h-t) is too large, a decrease in torque is likely to occur.

Quantitatively, a difference Δ (h-t) between the height h of the step portion 25 of the tooth portion 2 and the thickness t of the flange portion 5 is more than 0mm and less than or equal to 3 mm. If the difference Δ (h-t) exceeds 0mm, the cogging torque is easily reduced. In the case where it is desired to further reduce the cogging torque, the above-described difference Δ (h-t) may be greater than or equal to 0.5mm, and further may be greater than or equal to 1.0 mm. If the above difference Δ (h-t) is less than or equal to 3mm, the cogging torque decreases and the decrease in torque is suppressed. In the case where it is desired to further suppress the decrease in torque, Δ (h-t) may be 2.5mm or less, and may be 2.0mm or less. This point can be obtained by referring to test example 6 described later.

When a part of the tip end of the tooth 2 protrudes from the flange 5 as described above, the corner of the end face 20 of the tooth 2 may be chamfered. Specifically, the tip of the tooth 2 includes an inclined surface 22 intersecting the end surface 20 of the tooth 2. When the inclined surface 22 is included, the cogging torque can be reduced more easily than when the corner of the end surface 20 is perpendicular. This is because the teeth 2 easily receive the magnetic flux of the magnet 95, and the rapid change in magnetic flux is easily alleviated. Further, if the inclined surface 22 is included, chipping and the like are less likely to occur at the corner portion of the end surface 20 of the tooth 2, and the strength of the tooth 2 is also excellent. Fig. 6A virtually shows the inclined surface 22 by a two-dot chain line.

The angle θ of the inclined surface 22 of the tooth 2 with respect to the extension surface of the end surface 20 is 5 ° or more and 60 ° or less. If the angle θ is 5 ° or more, the cogging torque is easily reduced. In the case where it is desired to further reduce the cogging torque, the above-described angle θ may be greater than or equal to 10 °, further may be greater than or equal to 20 °, and greater than or equal to 30 °. On the other hand, if the angle θ is 60 ° or less, the projecting height of the tooth portion 2 from the flange portion 5 is easily reduced, and a decrease in torque is easily suppressed. In the case where it is desired to further suppress the decrease in torque, the above-described angle θ may be 55 ° or less, and further may be 50 ° or less.

If the corner portion of the flange portion 5 is also chamfered, that is, if the inclined surface 54 is shown by a two-dot chain line in fig. 6B, the cogging torque is easily reduced for the same reason as described above. Further, the corner portions of the flange portion 5 are less likely to be chipped, and the strength of the flange portion 5 is also excellent. An angle α of the inclined surface 54 of the flange portion 5 with respect to an extension surface of the end surface 50 is 5 ° or more and 60 ° or less. If the above angle α is in this range, the cogging torque decreases as described above, and the decrease in torque is suppressed.

The tooth 2 may not have the step 25. In this case, for example, the outer peripheral surface of the tip end portion of the tooth portion 2 and the inner peripheral surface 520 of the through hole 52 of the flange portion 5 may be fixed by an adhesive or the like, or may be fixed by press fitting or the like. In the core 1 having no stepped portion 25, the perpendicular gap described above can be minimized between the tooth portion 2 and the flange portion 5, and therefore, a decrease in torque can be more easily suppressed. However, since the tooth portion 2 does not have the step portion 25, it is difficult to fix the tooth portion 2 and the flange portion 5 as compared with the case of having the step portion 25. Therefore, for example, as shown in fig. 6B, the inner peripheral surface 520 of the through hole 52 of the flange portion 5 includes the inclined surface 53 corresponding to the inclined surface 22 of the tooth portion 2. In this case, the inclined surface 53 of the flange portion 5 is supported by the inclined surface 22 of the tooth portion 2. Even if the core 1 described above does not have the step portion 25, the tip end portions of the tooth portions 2 can stably support the flange portion 5, and thus the manufacturability is excellent.

In fig. 6B, the end surfaces 20 of the tooth portions 2 and the end surfaces 50 of the flange portions 5 are illustrated as being coplanar, but the end surfaces 20 of the tooth portions 2 and their vicinities may protrude from the end surfaces 50 of the flange portions 5. In this case, the projecting amount of the tooth portion 2 from the end surface 50 of the flange portion 5 is preferably more than 0mm and less than or equal to 3 mm.

Constituent Material

The constituent material of the core 1 includes a soft magnetic material. Typically, the core 1 is mainly made of a soft magnetic material. Examples of soft magnetic materials include pure iron and iron-based alloys.

Pure iron herein means a purity of 99% or more, that is, a content of Fe (iron) of 99% or more by mass. Pure iron has the effect of having a high saturation magnetic flux density, excellent formability, and being easily densified by compression forming. Therefore, if pure iron is included, an iron core 1 having a high saturation magnetic flux density, a dense iron core 1 having a high relative density, and an iron core 1 having excellent manufacturability which is easy to mold in the manufacturing process are obtained. Further, if the core 1 is dense, the saturation magnetic flux density is easily further increased, and mechanical properties such as strength are also excellent.

The iron-based alloy herein contains additive elements, and the remainder is composed of Fe and unavoidable impurities. The iron-based alloy contains one or more than or equal to two additive elements. Examples of the additive element include Si (silicon), Al (aluminum), Cr (chromium), and the like. Specific examples of the iron-based alloy include an Fe — Si-based alloy that is an iron-based alloy containing Si, an Fe — Al-based alloy that is an iron-based alloy containing Al, and an iron-based alloy containing Cr in addition to Si or Al. The resistance of the iron-based alloy is greater than that of pure iron. Therefore, if the iron core 1 includes an iron-based alloy, the iron loss such as eddy current loss can be reduced, and the loss can be easily reduced. The iron core 1 may also contain both pure iron and iron-based alloys.

The powder compact constituting the main body portion 4 and the powder compact constituting the flange portion 5 are each an aggregate of powder particles made of a soft magnetic material. The powder compact is mainly formed by engaging the powder particles with each other by plastic deformation to maintain a predetermined shape. Typically, the powder compact can be produced by compression molding a raw material powder containing a powder made of a soft magnetic material using a mold, not shown.

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 core 1 includes the coated particles, the core loss such as eddy current loss can be reduced, and the loss can be easily reduced. In particular, if the iron core 1 includes powder particles made of pure iron and insulating-coated coating particles, the saturation magnetic flux density is high, the magnetic characteristics are excellent, and low loss is likely to occur. Examples of the constituent material of the insulating coating include oxides such as phosphate and silicon dioxide. The phosphate is excellent in adhesion to powder particles made of iron or an iron-based alloy, and also excellent in deformability. Therefore, the insulating coating composed of phosphate is easily deformed following the deformation of the iron-based powder particles, and is not easily damaged when molded. Therefore, a compact having a sound insulation coating can be produced. The iron core 1 has the above-described powder compact, and thus is likely to have low loss.

Relative density

It is preferable that the relative density of the core 1 is high and dense, since the magnetic properties such as saturation magnetic flux density and the like and the mechanical properties such as strength and the like of the core 1 are excellent. Quantitatively, the relative density of the body portion 4 and the relative density of the flange portion 5 are preferably 90% or more. If the above relative density is 90% or more, the core 1 has a high saturation magnetic flux density and is also excellent in strength. For example, when the flange 5 is disposed on the tooth portion 2, the tooth portion 2 and the flange 5 are prevented from being broken. When improvement of magnetic properties, improvement of mechanical properties, or the like is desired, the relative density is preferably 93% or more, more preferably 95% or more.

The relative density here means a ratio (%) of an actually measured density of the powder compact to a theoretical density of the powder compact constituting the core 1. The theoretical density can be used as an equivalent value to the true density of the soft magnetic material constituting the powder compact.

Other

The core 1 includes a resin portion, not shown, that fixes the tooth portion 2 and the flange portion 5. In the core 1 having the resin portion, the main body portion 4 and the flange portion 5 are not separated, and can be easily handled as a single body.

The resin portion is made of, for example, an adhesive filled in a gap between the tooth portion 2 and the flange portion 5. Alternatively, the resin part may be a molded part that integrally covers the body part 4 and the flange part 5. A part of the molding portion fills in the gap between the tooth portion 2 and the flange portion 5. The molded portion covering the core 1 also functions as a member for improving electrical insulation between the core 1 and the coil 80 (fig. 7), and further as a member for mechanical protection and protection from the external environment. The molding portion may integrally cover the core 1 and the coil 80 (fig. 7).

Manufacturing method

The powder compact constituting the body portion 4 and the powder compact constituting the flange portion 5 can be produced by compression-molding the raw material powder into a predetermined shape as described above. A press molding machine or the like can be used for compression molding. The raw material powder may further contain a binder and a lubricant in addition to the soft magnetic material powder. A lubricant may be applied to the die.

The average particle diameter of the soft magnetic material powder used as the raw material powder is, for example, 20 μm or more and 350 μm or less. If the average particle diameter of the powder is in the above range, the powder can be easily handled and can be easily compression molded. The average particle diameter of the powder may be 40 μm or more and 300 μm or less, and further may be 250 μm or less. The average particle diameter of the powder herein is a particle diameter measured by a laser diffraction/scattering particle diameter/particle size distribution measuring apparatus, and the cumulative mass of the particles is 50% of the mass of all the particles.

As the pressure during compression molding is higher, densification becomes easier, and the iron core 1 having a higher relative density can be manufactured. The pressure is, for example, 700MPa or more, and more preferably 980MPa or more.

The molded article is subjected to heat treatment as needed after compression molding. The strain is removed by, for example, heat treatment, thereby manufacturing the low-loss iron core 1. Alternatively, for example, the binder and the lubricant are removed by heat treatment. In the case where the raw material powder contains the above-described coated particles, the heat treatment temperature is preferably less than or equal to the decomposition temperature of the insulating coating.

(main action and Effect of the embodiment)

The core 1 of the embodiment has the flange portion 5, but the body portion 4 having the tooth portions 2 and the flange portion 5 are separate members. Therefore, in the core 1, the coil 80 can be disposed in each tooth portion 2 in a state where the flange portion 5 is not disposed in each tooth portion 2. The stator and the axial gap type rotating electrical machine having the core 1 as described above are excellent in manufacturability.

In particular, the core 1 of the embodiment has the frame-shaped flange portion 5 to expose the end faces 20 of the tooth portions 2, and the exposed area ratio is set to a specific range. Therefore, the axial gap type rotating electrical machine having the core 1 can suppress a decrease in torque and has high torque. The effect of suppressing the torque reduction will be specifically described by the following test examples.

[ stator ]

The stator 8 of the embodiment will be described with reference to fig. 7.

The stator 8 of the embodiment has: an iron core 1; and a coil 80 disposed in each tooth 2 of the core 1. The stator 8 is used in an axial gap type rotating electrical machine such as a rotating electrical machine 9. Fig. 7 illustrates a case where the core 1 shown in fig. 1 is provided.

Each coil 80 has a cylindrical portion formed by winding a wire in a spiral shape. The coil 80 of this example is a rectangular edgewise wound coil in which a winding is formed in a rectangular tube shape so as to cover a flat wire. Fig. 7 shows only the cylindrical portion, and both ends of the winding are not shown.

The stator 8 of the embodiment has the core 1 of the embodiment in which the tooth portion 2 and the flange portion 5 can be separated. Therefore, by separately manufacturing the coil 80 and fitting the coil 80 outside the tooth portions 2 before the flange portion 5 is arranged, the coil 80 can be easily arranged in each tooth portion 2. Further, if the flange portion 5 is fixed to the tip end portion of each tooth portion 2 after the coil 80 is inserted and penetrated through the tooth portion 2, the stator 8 can be manufactured in which the coil 80 is interposed between the yoke portion 3 and the flange portion 5 and the coil 80 is inserted and penetrated through the tooth portion 2. In the stator 8 having the core 1 as a component, the winding step of the winding and the arrangement step of the coil 80 to the tooth 2 can be performed as separate steps in the manufacturing process. Therefore, it is not necessary to directly wind the wire around each tooth 2. Therefore, the winding is easily wound, and the coil 80 is easily manufactured.

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

[ rotating Electrical machine ]

The rotating electric machine 9 according to the embodiment will be described with reference to fig. 8.

Fig. 8 is a sectional view taken along a plane parallel to the rotation shaft 91 of the rotating electrical machine 9.

The rotating electrical machine 9 of the embodiment has the stator 8 of the embodiment. Specifically, the rotating electrical machine 9 is an axial gap type rotating electrical machine including a rotor 90 and a stator 8, and the rotor 90 and the stator 8 are arranged to face each other in the axial direction. The rotating electrical machine 9 described above can be used as a motor or a generator. Fig. 8 illustrates a single-rotor and double-stator type structure in which 1 rotor 90 is sandwiched between 2 stators 8. In addition, a configuration having 1 rotor 90 and 1 stator 8, a configuration assembled so that 1 stator 8 is sandwiched by 2 rotors 90, and the like are given.

The stator 8 and the rotor 90 are housed in a case 92 having a cylindrical inner space. The case 92 has a cylindrical portion and 2 plate portions. The cylindrical portion surrounds the outer peripheries of the stator 8 and the rotor 90. Plate portions are disposed on both sides of the cylindrical portion. The stator 8 and the rotor 90 are housed in a case 92 so as to be sandwiched between 2 plate portions. The stator 8 is fixed to the housing 92 by fitting the outer peripheral surface of the yoke portion 3 of the core 1 into the plate portion of the housing 92. The two plate portions have through holes in the central portions thereof. A bearing 93 is provided in the through hole, and the rotary shaft 91 is inserted through the bearing 93. Further, a bearing, not shown, is provided in the shaft hole 39 of the yoke 3, and the rotary shaft 91 is inserted through the bearing. The rotation shaft 91 penetrates the housing 92.

The rotor 90 is a flat plate-like member having a plurality of magnets 95 and a rotor body supporting the magnets 95. Each magnet 95 is, for example, a flat plate having a planar shape corresponding to the planar shape of the flange 5. The rotor body is an annular member and is rotatably supported by the rotary shaft 91. The magnets 95 are arranged at equal intervals in the circumferential direction of the rotor body. Each magnet 95 is magnetized in the axial direction of the rotary shaft 91. The magnetization directions of the magnets 95 adjacent in the circumferential direction of the rotor main body are opposite to each other. If the rotor body rotates, the magnet 95 also rotates together with the rotor body.

The stator 8 is disposed such that the end face 20 of the tooth portion 2 and the end face 50 of the flange portion 5 face the magnet 95 of the rotor 90. When the rotor 90 rotates, the end surfaces 20 of the tooth portions 2 and the end surfaces 50 of the flange portions 5 receive magnetic fluxes from the rotating magnets 95.

The rotating electrical machine 9 of the embodiment has the stator 8 of the embodiment. Since the stator 8 is easily assembled as described above, the rotating electrical machine 9 is excellent in manufacturability. Further, since the rotating electrical machine 9 according to the embodiment includes the stator 8 according to the embodiment, it is possible to suppress a decrease in torque and to obtain high torque.

[ test examples ]

A torque when a core having an annular yoke portion, a plurality of tooth portions, and flange portions provided at end portions of the respective tooth portions was used in a stator of a three-phase ac axial gap motor was investigated by simulation.

In the following experiments, the analysis was performed using electromagnetic field analysis software, here "JMAG" manufactured by JSOL corporation. The iron core used in the simulation was molded into a compact having a relative density of 90% or more, using pure iron as a constituent material. The inner and outer peripheral shapes of the flange portion and the end faces of the tooth portions are similar trapezoidal shapes, and are substantially similar to the peripheral surfaces of the tooth portions. The flange portion and the tooth portion have trapezoidal long side portions disposed on the outer peripheral edge side of the yoke portion in the flange portion. The sizes of the cores are substantially the same. In the following experiments, except for the shape of the core and the points where the intervals between the teeth and the flange are different, the torque was examined by setting the energization condition of the coil disposed in the teeth and the rotation condition of the magnet disposed on the tip side of the teeth to be the same.

[ test example 1]

In this test, the influence on the torque due to the difference in the division position was examined with respect to the model of the core having the yoke portion, the tooth portion, and the flange portion.

(Explanation of sample)

The core of sample No.100 is an ideal shape in the case where the yoke portion, the tooth portion, and the flange portion are assumed to be integrally molded. The core of sample No.100 was not an assembly of a plurality of segments, but was an integrally molded product, and there was no gap that could become a magnetic gap between the yoke portion and the tooth portion and between the tooth portion and the flange portion.

The core of sample No.101 is a core in which the tooth portions and the flange portions are divided from the ideal core of sample No. 100. That is, the core is a member in which the yoke portion and the tooth portion are integrally molded, and the flange portion is independent of the integrally molded member. The flange portion is a flat plate member having no through-hole and is joined to an end face of the tooth portion. Therefore, the core of sample No.101 has a gap between the tooth portion and the flange portion, which can be a magnetic gap. The planar area of the gap is equal to the sectional area of the tooth. The gap interval was set to 0.1 mm. In the iron core of sample No.101, the magnetic gap is an orthogonal gap disposed in a direction orthogonal to the magnetic flux.

The cores of sample nos. 102 and 103 are divided into yoke portions and tooth portions, as compared with the ideal core of sample No. 100. That is, each core is a member in which the tooth portion and the flange portion are integrally molded, and the yoke portion is independent of the integrally molded member.

In the core of sample No.102, the yoke is a flat plate material having an annular shape, and the end face of the tooth is joined to the surface of the yoke. Here, the surface of the yoke and the end surfaces of the teeth are flat surfaces. Therefore, the core of sample No.102 has a gap between the yoke and the tooth, which can be a magnetic gap. The planar area of the gap is equal to the sectional area of the tooth. The gap interval was set to 0.1 mm. In the iron core of sample No.102, the magnetic gap is an orthogonal gap disposed in a direction orthogonal to the magnetic flux.

In the core of sample No.103, the yoke is an annular flat plate member having a through hole into which one end portion of the tooth portion is inserted. Therefore, in the core of sample No.103, an annular gap which can be a magnetic gap exists between the inner peripheral surface of the through hole of the yoke portion and the outer peripheral surface of the one end portion of the tooth portion. The annular gaps are provided at uniform intervals in the circumferential direction of the through-hole, and the intervals are set to 0.1 mm.

The core of sample No.104 is a core in which teeth are divided in a direction orthogonal to the axial direction of the ideal core of sample No. 100. Namely, the iron core has the following divided pieces: a part of the tooth part and the yoke part are formed into a cutting piece of an integrated molding; and a division piece in which the remaining portion of the tooth portion and the flange portion are integrally molded. Therefore, the core of sample No.104 has a gap that can be a magnetic gap at the middle position in the axial direction of the tooth. The planar area of the gap is equal to the sectional area of the tooth. The gap interval was set to 0.1 mm. In the iron core of sample No.104, the magnetic gap is an orthogonal gap disposed in a direction orthogonal to the magnetic flux.

The core of sample No.1 is a core in which the tooth portions and the flange portions are divided from the ideal core of sample No. 100. That is, the core is a member in which the yoke portion and the tooth portion are integrally molded, and the flange portion is independent of the integrally molded member. The flange portion is a frame-shaped member having a through hole into which the tip end portion of the tooth portion is inserted, and the end face of the tooth portion is exposed from the through hole. In the core of sample No.1, an annular gap which can be a magnetic gap is formed between the outer peripheral surface of the tip end portion of the tooth portion and the inner peripheral surface of the through hole of the flange portion. The annular gaps are provided at uniform intervals in the circumferential direction of the through-hole, and the intervals are set to 0.1 mm. The tooth portion has a stepped portion at a tip end portion. The height h of the step portion is equal to the thickness t of the flange portion. The exposed area ratio of the core of sample No.1 was 37.7%. The method of obtaining the exposed area ratio is described in test example 2.

(test conditions)

In this test, a motor having the following stator core was assumed, and the torque of the motor was examined.

(Condition of stator core)

The number of coil turns is 30 turns.

The iron core is a 14-pole 12-slot iron core.

The cross-sectional area of the tooth portion was 102mm²。

The yoke has an outer diameter of 100 mm.

The yoke has an inner diameter of 70 mm.

The torque (N · m) of each sample is shown in table 1. Further, the reduction rate (%) of the torque of each sample was determined based on the torque of sample No. 100. The reduction rate of the torque was determined by { (torque of each sample-torque of sample No. 100)/torque of sample No.100 }. times.100. The reduction rate (%) of the torque is also shown in table 1.

[ TABLE 1]

As shown in Table 1, it is understood that the reduction rate of the torque of sample No.1 with respect to sample No.100 is smaller and has a high torque as compared with samples No.101 to No. 104. Quantitatively, the reduction rate of the torque of sample No.1 was less than 7%, and further less than or equal to 5%. One reason for this is that sample No.1 has the yoke portion and the tooth portion integrated with each other, and the magnetic flux is likely to pass through the yoke portion from the tooth portion. This is confirmed by the fact that the torque of sample No.101 is higher than that of sample No. 102. As another reason, it is considered that the gap generated between the divided pieces in the core of sample No.1 is small, and the gap is not easily formed into a magnetic gap, particularly an orthogonal gap. This is confirmed by the fact that the torques of sample No.101, No.102, No.104, which had a large orthogonal gap, were very small, and the torque of sample No.1 was large as compared with the torque of sample No. 101.

From this test, it is shown that, when a core having a yoke portion, tooth portions, and flange portions is divided, the following configuration is preferable. The yoke portion and the tooth portion are integrated, and the flange portion is an independent component. The flange portion is provided with a through hole. The teeth are inserted into the through-holes, and end faces of the teeth are exposed from the through-holes.

[ test example 2]

In this test, the size of the through hole in the flange portion was changed and the area of the end face of the tooth portion exposed from the through hole was changed with respect to the core of sample No.1 used in test example 1. The influence on the torque due to the difference in the area of the tooth portion exposed from the through hole of the flange portion was examined.

The basic structure of the iron core of each sample used in this test was the same as that of sample No. 1. That is, the distance between the outer peripheral surface of the tip end of the tooth portion and the inner peripheral surface of the through hole of the flange portion is 0.1mm, the tooth portion has a step portion, and the height h is equal to the thickness t. The interval is uniform in size over the entire circumference of the through-hole.

For each sample, the area S in the outer peripheral edge of the flange portion was determined₅And the area S of the end face of the tooth part exposed from the through hole of the flange part₂. Convex partArea S of the edge₅The area of the through hole including the flange portion. By (S)₂/S₅) X 100 to determine the area S of the teeth₂Area S relative to the flange part₅The ratio of (a) to (b), i.e., the exposed area ratio (%), is shown in table 2. The torque (N · m) of each sample is shown in table 2. Further, the torque reduction rate (%) of each sample was determined based on the torque of sample No.100 as in test example 1, and the results are shown in table 2.

[ TABLE 2]

As shown in Table 2, it is understood that the reduction rate of the torque of samples No.1 to No.3 with respect to sample No.100 is smaller and has a high torque as compared with sample No. 105. Quantitatively, the reduction rate of the torque of samples No.1 to No.3 was less than 7%. In particular, the reduction rate of the torque of samples No.1, No.2 was less than or equal to 5%. One reason for this is that the cores of samples nos. 1 to 3 have a higher exposed area ratio than the core of sample No.105, and therefore the teeth exposed from the through-holes of the flange portion directly receive magnetic flux, and the magnetic flux easily passes through the teeth from the flange portion.

From this test, it is shown that if the exposed area ratio is greater than or equal to 5.5%, particularly greater than or equal to 7.5%, a decrease in torque can be effectively suppressed, and high torque is easily obtained. Further, it is found from this test that, if the exposed area ratio is higher, here, 30% or more, and further 35% or more, the decrease in torque is more easily suppressed. The upper limit of the exposed area ratio is not particularly limited, and may be, for example, 90% as long as the flange portion can be provided in the tooth portion.

[ test example 3]

In this test, the core of sample No.2 used in test example 2 was changed in such a manner that the end faces of the tooth portions were arranged to be offset to one side in the through-holes of the flange portions, and the interval between the outer peripheral surfaces of the tip end portions of the tooth portions and the inner peripheral surfaces of the through-holes of the flange portions was not uniform in the circumferential direction of the through-holes. The influence on the torque due to the difference in the size of the gap was examined.

The iron core of each sample used in this test was such that the area of the end face of the tooth portion and the area inside the outer peripheral edge of the flange portion were constant, and the exposed area ratio was 10.2% which is the value of sample No. 2. The inner and outer peripheral shapes of the flange portion and the end faces of the tooth portions are similar trapezoidal shapes, and are substantially similar to the peripheral surfaces of the tooth portions. The tooth has a step, and the height h is the thickness t. The size of the through-hole in the flange portion was changed for each core as described above so that the above-described interval satisfied the maximum difference (mm) in the interval shown in table 3. The end faces of the tooth portions are disposed to be offset to one side with respect to the through holes of the flange portion. The maximum difference of the intervals in table 3 means the difference between the maximum value of the intervals and the minimum value of the intervals.

Here, a region where the outer peripheral surface of the tip end portion of the tooth portion and the inner peripheral surface of the through hole of the flange portion are in contact, that is, a close region where the interval is 0.05mm or less is mainly provided on the same side in the circumferential direction of the yoke portion. The large-interval portion is provided on the opposite side of the yoke portion in the circumferential direction. The minimum value of the above-mentioned intervals is 0mm, and the maximum value of the above-mentioned intervals is equal to the maximum difference of the intervals shown in table 3 (mm). In addition, the ratio of the length of the flange portion in the circumferential direction to the circumferential length of the through hole of the flange portion, i.e., the bonding ratio, in the approach region was 45% and exceeded 20%.

The torque (N · m) of each sample is shown in table 3. Further, the torque reduction rate (%) of each sample was determined based on the torque of sample No.100 as in test example 1, and the results are shown in table 3.

[ TABLE 3]

As shown in Table 3, it is understood that samples Nos. 4, 5, and 15 have a small reduction rate of the torque with respect to sample No.100 and a high torque. Quantitatively, the reduction rate of the torque in samples No.4, No.5, and No.15 was less than 7%. In particular, the reduction rate of the torque of samples No.4, No.5 is less than or equal to 5%, which is less than the reduction rate of the torque in sample No. 15. One reason for this is that the maximum difference between the intervals of the cores of samples No.4 and No.5 is small and less than 0.40mm, and the gap between the tooth portion and the through hole of the flange portion is less likely to become a magnetic gap. In particular, the reduction rate of the torque in sample No.5 is less than or equal to 3%, and the reduction in torque is small as compared with sample No. 4. From this fact, in the core of sample No.5, the maximum difference in the gap is smaller and equal to or smaller than 0.30mm, and therefore the gap between the tooth portion and the through hole of the flange portion is less likely to become a magnetic gap. In this test, the core of sample No.5 had a gap of 0.30mm between the tooth portion and the through hole of the flange portion, but had a high torque of the same level as that of sample No. 2.

From this test, it is shown that if the maximum difference of the intervals is less than 0.40mm, preferably less than or equal to 0.30mm, the decrease of the torque can be effectively suppressed, and the high torque is easily obtained. Further, the lower limit of the maximum difference of the intervals is not particularly limited. The maximum difference in the interval may be, for example, 0mm as long as the flange portion and the tooth portion can be manufactured with high accuracy and can be assembled without damaging both.

[ test example 4]

In this test, similarly to test example 3, the core of sample No.2 used in test example 2 was changed to a state in which the interval between the outer peripheral surface of the tip portion of the tooth portion and the inner peripheral surface of the through hole of the flange portion was not uniform in the circumferential direction of the through hole. The flange portion is provided with an approach region having the above-described interval of 0.05mm or less, and the length of the approach region in the circumferential direction of the through hole of the flange portion and the arrangement position of the approach region are changed. The influence on the torque due to the difference in the length and arrangement position of the proximity region was examined.

The basic matters of the iron core of each sample used in the test are the same as those in test example 3. That is, the area of the end face of the tooth portion and the area inside the outer peripheral edge of the flange portion are constant. The exposed area ratio was 10.2%, the teeth had stepped portions, and the height h was equal to the thickness t. The maximum difference in spacing is 0.20mm, less than 0.40 mm.

The core of sample No.7 has an approach area on the outer peripheral side of the yoke in the flange portion. The core of sample No.6 has an approach region on the inner peripheral edge side of the yoke portion in the flange portion, and the above-described length of the approach region is shorter than that of sample No. 7.

For each sample core, the perimeter L of the through hole of the flange portion was determined₅And a length L in the circumferential direction of the flange portion in the approach region₅₅. And, by (L)₅₅/L₅) X 100 to find the length L of the proximity region₅₅Relative to the circumference L₅The ratio of (a) to (b), i.e., the joining ratio, is shown in table 4. The torque (N · m) of each sample is shown in table 4. Further, the torque reduction rate (%) of each sample was determined based on the torque of sample No.100 as in test example 1, and the results are shown in table 4.

[ TABLE 4]

As shown in table 4, it is understood that the iron cores of sample nos. 6, 7 and 16 have a small reduction rate of the torque with respect to sample No.100 and a high torque. Quantitatively, the reduction rate of the torque in samples No.6, No.7, and No.16 was less than 7%. In particular, the reduction rate of the torque of samples No.6, No.7 was less than or equal to 5%, which was less than the reduction rate of the torque in sample No. 16. One reason for this is that the joining ratio of the core-approaching regions of samples No.6 and No.7 exceeds 20%, and the magnetic flux is likely to pass through the tooth portions from the approaching regions. In particular, the reduction rate of the torque in sample No.7 is less than or equal to 3%, and the reduction in torque is small as compared with sample No. 6. It is considered that, in the core of sample No.7, the joining ratio of the proximity region is larger and 35% or more, and therefore it is easier to pass the magnetic flux from the proximity region through the tooth portion. In this test, the maximum difference in the gap in the core of sample No.7 was larger than that in sample No.2, but the core of sample No.7 had a high torque equal to or higher than that of sample No. 2.

From this test, it is shown that if the joining ratio of the approach region exceeds 20%, preferably 30% or more, and more preferably 35% or more in the case where the flange portion has the approach region, the reduction of the torque can be effectively suppressed, and the high torque is easily obtained. In addition, in order to increase the joining ratio of the proximity region, for example, the proximity region is shown to be provided in the outer peripheral region of the yoke in the flange portion. Further, the upper limit value of the joining ratio of the approach region is not particularly limited. For example, the flange portion may have an approach region over the entire circumference of the through hole. That is, the joining ratio of the proximity region may be 100%.

[ test example 5]

In this test, similarly to test example 4, the core of sample No.2 used in test example 2 was changed to a state in which the interval between the outer peripheral surface of the tip portion of the tooth portion and the inner peripheral surface of the through hole of the flange portion was not uniform in the circumferential direction of the through hole. In addition, the flange portion was provided with the proximity region having the interval of 0.05mm or less, and the arrangement position of the proximity region was changed. The influence on the torque due to the difference in the arrangement position of the proximity region and the difference in the rotation direction of the rotor was examined.

The basic matters of the iron core of each sample used in the test are the same as those in test example 4. That is, the area of the end face of the tooth portion and the area inside the outer peripheral edge of the flange portion are constant. The exposed area ratio was 10.2%, the teeth had stepped portions, and the height h was equal to the thickness t. The maximum difference in spacing is 0.2mm, less than 0.40 mm. The joining ratio of the approach region was 22% and exceeded 20%.

The cores of samples No.8, No.9 have access regions on opposite sides of the teeth in the flange portions where adjacent teeth are fixed. That is, the adjacent flange portions are disposed so that their adjacent regions face each other. In the iron core of sample No.8, coils of different phases were arranged in the adjacent teeth. In the core of sample No.9, coils of the same phase are arranged in the adjacent teeth.

The cores of samples No.10 and No.11 had the proximity region of each flange portion on the same side in the circumferential direction of the yoke portion. The core of sample No.10 has the vicinity of each flange portion on the same side as the rotation direction of the rotor. The core of sample No.11 has the vicinity of each flange portion on the opposite side to the rotation direction of the rotor.

The torque (N · m) of each sample is shown in table 5. Further, the torque reduction rate (%) of each sample was determined based on the torque of sample No.100 as in test example 1, and the results are shown in table 5.

[ TABLE 5]

As shown in table 5, it is understood that samples nos. 8 to 11 have a small reduction rate of torque with respect to sample No.100 and have high torque. Quantitatively, the reduction rate of the torque in samples No.8 to No.11 was 5% or less. One reason for this is that the cores of samples nos. 8 to 11 have the proximity region, and thus the magnetic flux can easily pass through the tooth portion from the proximity region. In this test, the cores of samples No.8 to No.11 had a gap between the tooth portion and the through hole of the flange portion, but had high torque of the same level as that of sample No. 2.

In this test, it can be said that, in the case where the flange portion where the adjacent teeth are fixed has an approach region on the side opposite to the teeth, if coils of the same phase are arranged in the respective teeth, the decrease in torque is more easily suppressed (see sample No. 9). In this test, it can be said that, when the proximity regions of the respective flange portions are provided on the same side in the circumferential direction of the yoke portion, if the arrangement positions of the proximity regions are on the same side as the rotation direction of the rotor, the decrease in torque is more easily suppressed (see sample No. 10).

[ test example 6]

In this test, the heights h (mm) of the step portions of the tooth portions and the projecting heights of the tooth portions exposed from the through holes of the flange portions were changed for the cores of sample No.1 used in test examples 1 and 2. The influence on the torque and the influence on the cogging torque due to the difference in the tooth projecting height were examined.

In this test, the same as sample No.1 was applied except that the height h (mm) of the step portion of the tooth portion was changed with respect to the core of sample No.1 used in test examples 1 and 2. That is, the area of the end face of the tooth portion and the area inside the outer peripheral edge of the flange portion are constant. The exposed area ratio was 37.7%. The distance between the outer peripheral surface of the tip portion of the tooth portion and the inner peripheral surface of the through hole of the flange portion was 0.1 mm. The interval is uniform in size over the entire circumference of the through-hole. The height h (mm) of the step portion of the tooth portion and the thickness t (mm) of the flange portion of each sample are shown in table 6.

In the core of sample No.1, the angle of intersection between the bottom surface of the stepped portion and the peripheral surface of the stepped portion is 90 ° at the corner of the tip end portion of the tooth portion. The intersection angle between the inner peripheral surface of the flange portion and the surface of the flange portion placed on the bottom surface of the stepped portion is 90 °. The end surfaces of the tooth portions and the flange portion are coplanar. The points relating to the intersection angles were the same in the samples having the stepped portions of the respective samples of test examples 1 to 5.

The samples nos. 12 to 14 were formed in such a shape that the corner portions of the portions projecting from the end faces of the flange portions were chamfered at the tip end portions of the tooth portions. The tip of the tooth includes an inclined surface intersecting with an end surface of the tooth. The angle of the inclined surface of the tooth with respect to the extension surface of the end surface of the tooth is selected from the range of 5 DEG to 60 deg. The inclined surfaces of the tooth portions are exposed from the through holes of the flange portion. In addition, the area of the end face of the tooth portion in samples nos. 12 to 14 is slightly smaller than sample No.1 strictly by the chamfered shape. Therefore, the exposure area ratio here is the maximum cross-sectional area of the portion of the tooth portion located on the end face of the flange portion.

The torque (N · m) and cogging torque (cN · m ) of each sample are shown in table 6. Further, the torque reduction rate (%) of each sample was determined based on the torque of sample No.100 as in test example 1, and the results are shown in table 6.

[ TABLE 6]

As shown in Table 6, it is understood that samples Nos. 1 and 12 to 14 have a small reduction rate of the torque with respect to sample No.100 and a high torque. Quantitatively, the reduction rate of the torque in samples No.12 to No.14 was 5% or less. One reason for this is that, since the cores of samples nos. 12 to 14 have a high exposed area ratio as in sample No.1, the teeth exposed from the through-holes of the flange portion receive magnetic flux directly, and the magnetic flux is made to easily pass through the teeth from the flange portion.

However, in samples nos. 1 and 12 to 14, the magnitude of the cogging torque was different. The larger the difference Δ (h-t) (mm) between the height h (mm) of the step portion of the tooth portion and the thickness t (mm) of the flange portion, the smaller the cogging torque. Quantitatively, the difference Δ (h-t) exceeds 0mm, here further equal to or more than 1mm, as compared with sample No.1 in which the difference Δ (h-t) is 0mm, and if larger, the cogging torque can be reduced more effectively. However, the larger the difference Δ (h-t), the lower the torque can be seen. This is confirmed, for example, by comparative reference of samples No.12 and No. 14.

This test shows that when the tip end of the tooth portion has a stepped portion, the cogging torque can be reduced by adjusting the height h of the stepped portion of the tooth portion and the thickness t of the flange portion so that the region on the end surface side of the tooth portion protrudes from the through hole of the flange portion. In particular, it can be said that if the difference Δ (h-t) exceeds 0mm and is less than or equal to 3mm, the cogging torque is reduced and the decrease in torque is suppressed.

As shown in test examples 1 to 6, in the cores having the flange portions at the tip end portions of the tooth portions, the following conditions (1) to (3) are satisfied, and thereby a decrease in torque can be suppressed as compared with the case of an integral body of the tooth portions, the yoke portion, and the flange portions. Further, by satisfying the following condition (1), it can be said that the axial gap type rotating electric machine and the stator used in the rotating electric machine are easier to assemble and excellent in manufacturability compared to the above-described integrated body.

(1) The yoke portion and the tooth portion are integrated, and the flange portion is a member divided with respect to the tooth portion.

(2) The flange portion has a through hole, and an end face of the tooth portion is exposed from the through hole.

(3) The ratio of the end surfaces of the tooth portions exposed from the through holes of the flange portion, i.e., the exposed area ratio, is 7.5% or more.

The present invention is not limited to these examples, but is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims. For example, in the above-described test examples 1 to 6, the material and relative density of the core, the shapes of the tooth portions and the flange portions, and the like can be changed.

Description of the reference numerals

1 iron core

2 tooth part, 20 end face, 21 peripheral surface, 22 inclined surface, 25 step part, 250 bottom surface, 251 peripheral surface

3 yoke, 30 surface, 39 axle hole

4 main body part

5 flange portion, 50 end face, 51 outer peripheral edge, 52 through hole, 520 inner peripheral surface 53, 54 inclined surface, 55 approaching region, 56 outer peripheral region, 57 inner peripheral region

8 stator, 80 coil

9 rotating electric machine, 90 rotor, 91 rotating shaft, 92 casing, 93 bearing 95 magnet

g_minMinimum value of interval, g_maxMaximum value of interval

h height, t thickness, delta (h-t) height and thickness difference, theta, alpha angle